Rock Engineering Research Foundation

Annual Review 2013

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W hen I look back on what 2013 meant for BeFo, the Rock Engineering Research Foundation, it is primarily our research projects, the meeting places, and the training courses we arrange for the rock

engineering sector that stand out. These form the backbone of BeFo activities, and characterise the work of the board, the Programme Board and our everyday administrative work.

Many of the research projects involve close collaboration with industry, and I am pleased to see many rock projects are under way – in planning, construction and operational stages – where researchers have access to real-life situations.

I am also pleased to welcome six new principals – TeliaSonera, Sika, Norconsult, Swerea KIMAB, GMA and EDZ-consulting; these are companies that see the importance of research resulting from funding activities.

The Swedish Research Council Formas and the Swedish Transport Administration, supported by industry, invited applications for funding – GeoInfra – and this resulted in many applications to BeFo and other organisations. No fewer than 19 project applications relating to the GeoInfra call and other initiatives were processed by the BeFo Programme Board at the year’s first meeting in January 2013. We had seen a drop in the number of new research projects in 2012, but this was expected because of the impending GeoInfra call; instead, many researchers invested both time and energy in applying for the new five-year funding. In 2013, 15 new research projects were started and 12 were completed, which is a relatively large turnover. As of 31 December 2013, BeFo was running 27 projects in the various research areas; the projects are described later in this annual review.

An unusual project setup is TRUST (TRansparent Underground STructure), which comprises a number of national projects, many based on the GeoInfra call, that are coordinated to provide mutual support, common test objects, etc. Read more about this interesting setup later in this annual review. Maybe TRUST will be the future model for research management? We look forward to evaluating this when the projects start producing results.

The Nordic Grouting Symposium was launched in Gothenburg in 1992 and has become a tradition, with the event rotating between the Nordic countries. In 2010, the first Nordic Rock Mechanics meeting was held in Kongsberg in Norway. Sweden took over the baton for both events in 2013, and arranged a two-day event in Gothenburg on 13-14 November – the 7th Nordic Grouting Symposium and the 2nd Nordic Rock Mechanics Symposium. The event included a Professional Discussion where we discussed issues in the technical field between, but also within, rock mechanics and grouting. There was also a joint dinner, and we hope to have helped establish greater contact between the two disciplines.

The annual Rock Mechanics Day was held on 11 March 2013. The guest speaker was Professor Frederic L. Pellet, INSA University of Lyon, France, whose speech was on ‘Thermal and Mechanical Damage of Rocks under Different Loading Conditions and Consequences for Underground Opening Behaviour’. The other 14 lectures ranged from mining-related subjects, Eurocode, inflow, maintenance issues and pre-investigation studies, to challenges in major infrastructure projects. The lecture ‘Maintenance of Road and Rail Tunnels – an Expensive Business’, presented by Anna Engström, Bergab, was awarded Best Lecture Prize by the jury. The Swedish Rock Mechanics Group wants to recognise engineers who have submitted fine degree projects, and now awards a prize at the Rock Mechanics Day. In 2013 the prizewinner was Erik Storvall from Luleå University of Technology, for his degree project ‘Rill Mining in Dammsjön - Numerical Analysis of Future Mining’.

One person who has been very active and popular in our sector for a long time is Gunnar Nord, who is now winding down; he was thanked at the Rock Mechanics Day for long and faithful service. As a popular moderator and discussion leader, he led many meetings and seminars.

BeFo arranged three popular seminars in 2013. These were ‘Eurocode’, led by Håkan Stille, ‘The Rock Engineer’s Tools for Managing Uncertainties’, led by Lars Olsson, and ‘Tunnel Lining for Road and Rail Tunnels’, arranged together with the Swedish Transport Administration and hosted by Thomas Dalmalm. We regard seminars as an important part of our work, and we encourage anyone who wishes to propose an interesting subject to contact us.

Grouting is a key activity in rock construction, particularly in traffic tunnels. It is often very time consuming and therefore costly for tunnel projects. Grouting expertise is vital if it is to be carried out well and efficiently, yet there is no training course for professionals and other practitioners. Swedish research into grouting of hard rock began at the end of the 1980s and is pioneering; the knowledge is there but needs to be implemented in practice among project planners and constructors. One of BeFo’s strategic areas of activity is training and, last autumn, we arranged the first BeFo training course in grouting. This was a first step in disseminating grouting knowledge to industry. The 22 participants at the two-day course at Chalmers University of Technology in Gothenburg were a mixture of professionals, clients, manufacturers and project planners. The course was successful, and we hope to continue this training to improve understanding of grouting, in the hope that the knowledge will be built into our tunnels from now on.

In conclusion, returning to the large number of research projects that were concluded in 2013, we encourage researchers and the sector in general to ensure that findings benefit the sector. And here we must all help throughout the chain to ensure that good results are applied in practice.

Stockholm February 2014Per Tengborg

Research Director, CEO, BeFo

BeFo in 2013

Lena Malm, Chair of Gothenburg City Council, Gothenburg, and Ulf Lindblom, Chairman of BeFo.

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Principals 2014:• Clients: Elforsk; SKB, Swedish Nuclear Fuel and Waste Management Co (SKB); Stockholm County Council Traffic Board (SLL); TeliaSonera; Swedish Transport Administration.• Contractors: Besab; Byggs Sprutbetong; NCC; Skanska; Veidekke.,• Consultants: Bergab; EDZ-consulting; Geosigma; Gecon; Golder Associates; JLM Tunnelkonsult; Nitro Consult; Norconsult; Petro Team Engineering; Pöyry SwedPower; Ramböll; Sweco; Saanio & Riekola; Tunnel Engineering, Tyréns; WSP Sverige; ÅF-Infrastructure; Swerea KIMAB. • Manufacturers: Atlas Copco; Cementa; GMA Ground Machinery Applications; Sandvik Mining and Construction Sverige; Sika Sverige.• Universities: Chalmers University of Technology (Chalmers); KTH Royal Institute of Technology (KTH); Luleå University of Technology (LTU); Lund University (LTH).

Rock Engineering Research FoundationBoard 2014: Ulf Lindblom/Gecon, Chairman; Anna Andrén/Swedish Transport Administration; Lars-Olof Dahlström/NCC Teknik; Ulf Håkansson/Skanska; Bo-Göran Johansson/Atlas Copco CMT Sweden; Dick Karlsson/Sweco; Mats Ohlsson/SKB; Maira Slokenbergs/ÅF Infrastructure.

Programme Board 2014: Per Tengborg/BeFo, Chairman; Martin Brantberger, Bengt Niklasson/Geosigma; Tomas Cederhammar/Sika Sverige; Rolf Christiansson, Isabelle Olofsson/SKB; Torleif Dahlin/LTH; Catrin Edelbro/LTU; Tommy Ellison/Besab; Ann Emmelin/Golder Associates; Anna Engström/Bergab; Åsa Fransson/Chalmers; Magnus Eriksson/Swedish Geotechnical Institute (SGI); Johannes Hansson/Atlas Copco Rock Drills; Thomas Janson, Pia Söderlund /Tyréns; Fredrik Johansson/KTH;

Henrik Jonsson/Vattenfall Research & Development; Tomas Karlberg, Hans-Åke Mattsson/ÅF-Infrastructure; Kent Lundin/TeliaSonera; Carl Johan Gårdinger/NCC Construction Sverige; Andrius Rimsa/Pöyry SwedPower; Mattias Rosslin, Erik Stål/Swedish Transport Administration; Thomas Sträng/SLL; Robert Sturk/Skanska; Carl-Olof Söder/Sweco; Peder Thorsager/Ramböll Sverige; Marie von Matérn/WSP Sverige; Antti Öhberg/Saanio & Riekkola, Finland.

Administration 2014: Per Tengborg: Research Director, CEO; Eva Friedman: office & administration

Programme Board at the Ulvin Tunnel at Morskogen, Joint Project, Norway 2013. Photo: J Hansson & BeFo.

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Eurocode and rock THE WORKSHOP prepared information relating to the revision of the current Euronorm for Geotechnical Designs (EN7) with regard to rock mechanics. The aim was to ensure that rock mechanical issues were included in the EU standard, and to encourage further work to influence the content in Eurocode for hard rock.

Tools for managing uncertaintiesTOOLS WERE presented that simplify and streamline management of uncertainties in underground construction. Practical examples showed how the tools could be used in

various phases and activities, and for managing risks in planning and construction phases of underground projects. The use of the tools in special situations, such as tenders and resource planning, was shown.

Tunnel lining for road and rail tunnels.BEFO AND the Swedish Transport Administration arranged a seminar on the need for tunnel lining, its importance and requirements. Updating of the regulatory framework was discussed, and inspection, damage, maintenance and sealing systems presented. ◆

BeFo seminars 2013

Svenska BergmekanikgruppenTHE SWEDISH National Group of ISRM is the national body within ISRM. The main secretariat is in Lisbon, and BeFo is responsible for the Swedish secretariat. The Swedish National Group of ISRM and BeFo jointly arrange the annual Rock Mechanics Day. For information and membership, see www.befoonline.org

ISRM (the International Society for Rock Mechanics) FORMED IN 1962, works internationally to promote the science of rock mechanics and its applications, with the aim of promoting high standards of professional practice. The society develops, for example, suggested methods for field and laboratory testing. The society’s activities are organised in commissions in various fields, such as the Testing Methods Commission, Applied Geophysics Commission, Design Commission and Education Commission. On Swedish initiative, a new commission has been set up – Grouting of Fractured Rock – with Håkan Stille, KTH, as chair.See www.isrm.net

BK and ITA (International Tunnelling Association) SWEDISH ROCK Construction Committee (BK) and International Tunnelling Association (ITA). BeFo is a member of BK, and is represented on its Council of Trustees. Together with BeFo, BK is the Swedish representative in ITA, which works for better use of underground space. Planning, construction, maintenance and safety of tunnels and underground

facilities are promoted by disseminating information and holding discussions. The work is mainly carried out in the form of working groups (13 in 2013), and Swedes participate in 12 of these. At the AGM in 2013, a new chairman was elected for 2013-2016, Søren Degn Eskesen from Denmark. The ITA publishes reports in various subject areas, and articles are published in Tunnelling and Underground Space Technology (TUST) which is issued 3-4 times a year. ITA was formed in 1974, and its secretariat is in Lausanne, Switzerland. See www.ita-aites.org

ITACUS (ITA Committee on Underground Space)ITACUS WORKS to promote underground construction and raise awareness of use of underground space. In conjunction with the Nordic symposia in Gothenburg in November 2013, the board of ITACUS arranged a workshop together with the City of Gothenburg and BeFo, with the Western Link and planning of underground facilities as main themes. The board also held a meeting and visited the symposia. BeFo collaborates with the organisation by disseminating knowledge about the opportunities afforded by long-term planning of underground construction. See www.ita-aites.org

BergsamBERGSAM IS an informal forum for the Swedish rock industry. Sector issues are discussed and influence exerted through written submissions, lobbying, or other initiatives to promote common interests. The network also works to improve expertise in the sectors. The following participate in the work: BeFo, SveMin, Swedish Aggregates Producers Association (SBMI), BK, Swedish Rock Blasting Contractors Association (BEF), and the Swedish Mineral Processing Research Association (MinFo).

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THE BASIC processes in grouting need to be more widely understood. BeFo arranged a course in grouting in a two-day training package in October 2013. The course was designed by BeFo and Johan Funehag (Chalmers), with the help of experts in the sector and industry. The course was fully-booked, and 22 participants –practitioners, contractors, clients, material manufacturers and project planners – attended the course at Chalmers in Gothenburg.

An evaluation at the end of the course showed that the participants felt that the course gave them greater understanding of grouting and the processes involved, and that the course met their expectations. The course will be followed up and improved by, for example, adapting the content to various practitioners.

The course reviewed the current state of knowledge in grouting: how the rock can be described, grouting technology, material properties and equipment. These four components must interact if grouting is to be effective. The results of grouting research over several decades need to

be disseminated and applied in practice, both by project planners and contractors.

The course corresponds to one of the goals of the BeFo research

programme 2012-2022, skills enhancement, where information and training are important. The next BeFo course is being planned. ◆

BEFO ARRANGED BeFo arranged the joint event on 13-14 November at Hotel 11 in Gothenburg, thereby gathering participants from the sectors for two days instead of arranging two separate symposia.

The 26 lectures and the 12 poster presentations in the programme are described in the Proceedings.

The event attracted 153 participants, from Norway, Finland, Sweden and Switzerland. A Professional Discussion workshop with the title ‘Grouting and Rock Mechanics’ served as a link between the two symposia. The workshop was led by Dr. Lars Hässler/Golder Associates with an introductory presentation by Johan Thörn/Chalmers. Approximately 60 participants joined the group discussions, and the results were presented on the morning of Day 2.

Eleven sector companies – consultants, manufacturers and suppliers – were represented at the exhibition.

Participants attended a gala dinner at Gothenburg City Hall. The Guest of

Honour was Lena Malm, Chair of the City Council, who emphasised the need for good town planning with modern infrastructure, including roads and tunnels.

The organisational baton was handed over to Siri Engen/Tekna/NFF/NBG and Ola Woldmo/Normet Scandinavia, as Norway will be arranging the next Nordic Grouting Symposium. The next Nordic Rock Mechanics Symposium will be held in Finland, and responsibility passed on to Erik Johansson, chairman of the Finnish Rock Mechanics Association/Saanio & Riekkola.

BeFo thanks everyone involved in the planning and implementation of the symposia: the Scientific and Organising Committee, Advisory Committee, group leaders in the Professional Discussion, etc.

BeFo also thanks the sponsors: Bekaert, GMA Ground Machinery Applications, Norconsult and Pretec. The Swedish Research Council (Formas) helped fund the event. ◆

Skills development: grouting in hard rock

7th Nordic Grouting Symposium and 2nd Nordic Rock Mechanics Symposium

Training course in grouting

Grouting exercise in fracture model. Participants examine the spread of grouting agent under varying conditions (water-cement ratio, water gradient).

Refreshments and discussions at the poster exhibition.

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TRUST is an R&D project in underground construction that promotes cooperation between researchers, R&D functions in the Swedish Transport Administration, and specialists in the sector.

It is important to build cost-effective underground facilities that are safe, environmentally sound, energy-efficient and easy to maintain. In recent years, Swedish and European energy and environmental goals and regulatory systems have been tightened, so it is important to develop and implement new methods and technologies for planning and construction of underground facilities.

The overall vision of TRUST is to promote research on sustainable development of urban underground infrastructure. This will help to improve methods and tools for planning, design and construction of underground facilities.

Participant organisations in TRUST are Chalmers, KTH, Faculty of Engineering at Lund University (LTH), LTU, NCC, Geological Survey of Sweden (SGU), Swedish Transport Administration, Tyréns, Uppsala University (UU) and Århus University (ÅU). TRUST currently comprises 8 projects, with a total project budget of just over SEK 70 million for the period 2012-2016. BeFo helps fund several of the TRUST projects. ◆

THIS IS a GeoInfra project, involving management of the coordinated initiative, TRUST. In this project, a multi- and inter-disciplinary approach is ensured by bringing together

researchers from the Swedish Universities of the Built Environment (SBU), i.e. Chalmers, KTH, LTU, LTH, UU, SGU, and a number of private companies.

The TRUST management project comprises two parts: coordination/communication and innovation/implementation.

Coordination, dissemination of information and communication between the various projects are fundamental parts of TRUST. This is attained through the following activities:(1) Information is disseminated internally via the TRUST Projectplace and externally via www.trust-geoinfra.se; (2) Regular telephone meetings; (3) Workshops arranged twice a year and conferences when necessary; (4) Research school for doctoral students; and (5) Setting up a database.

Models for collaboration on sustainable innovation between

universities and industry/society will be developed, particularly for underground construction. The research projects in the TRUST collaboration will use the Stockholm Bypass project as a testing ground for studying such issues as:

• Which are the most important players, and how is communication organised between research and practice?

• What aspects affect the innovation

processes, positively and negatively? • How does the TRUST

collaboration affect innovation processes in the individual projects and the innovative ability of the organisations involved?

• How should the university/industry collaboration be organised to improve the ability to innovate in underground construction?

The project is scheduled to run until 2016. ◆

TRUST – TRansparent Underground STructure

TRransparent Underground STructure (TRUST) – ManagementMaria Ask, LTU

TRUST comprises a number of projects that are coordinated via a management project (projects 2.3 and 3.1 have not yet started)

Research projects started in 2013

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THE PROJECT aim is to develop and adapt the method for combined measurement of DC resistivity and induced polarisation (DCIP), used for surveying ground properties in

urban environments. Another aim is to investigate how mapping of variations in properties in soil and rock can be improved. A third aim is to locate and map buried waste and contaminated soil in three dimensions (3D).

Unstable rock, groundwater inflow and other unpredictable ground conditions are risk factors that often cause delays and significantly increase costs during construction of underground infrastructure. Detailed knowledge is required about the rock base and soil layers, geological structures, geotechnical conditions, groundwater, etc. However, in practice it is impossible to build 3D models with sufficient spatial coverage solely on the basis of data from test drilling.

Old industrial land often lies in areas that are attractive for exploitation, but often little is known

about these facilities. Chemicals and waste may have been managed poorly, leaving contaminated soils. Problems may occur when underground infrastructure is built close to such areas, because groundwater levels change, transporting contaminants and creating environmental problems in or around the facility. This is why better methods are needed for mapping the extent of former industrial land and its properties. The same applies to former landfills. Old covered waste tips are now in the built-up zone, so these areas need to be reclaimed to make better use of the land for building or infrastructure.

Using modern measurement technology and interpretation software, the ground properties can be mapped in 3D in a relatively time- and cost-effective way. DCIP has shown great potential in mapping soil and rock quality and for investigating landfills and contaminated ground. By adapting and further developing the data collection technology, the method could be used in urban environments, which is often difficult today. By further developing the interpretation technology, it may be possible to obtain better characterisation of the properties in soil and rock. It may also be possible

distinguish between different types of waste and obtain information about the chemical state of contaminants. The following are participating in the project: Sara Johansson, Per-Ivar Olsson, Charlotte Sparrenbom, Håkan Rosqvist, Lund University; Gianluca Fiandaca, Esben Auken, ÅU; David Hagerberg, Mats Svensson, Tyréns AB; Mehrdad Bastani, SGU; Per Hedblom, Jonas Moberg, ABEM Instrument AB. The project is part of TRUST 2.1, with funding from GeoInfra, Formas, Swedish Transport Administration, BeFo, SBUF/Skanska, Tyréns, SGU and ABEM Instrument, and the project will continue until 2016. ◆

UNFORESEEN ground conditions are a risk factor that often leads to big delays and extra costs when underground facilities are being built. The aim of this project is to develop, test and demonstrate integrated use of and data from various geophysical measurement methods and in-situ methods like drilling to produce a prediction model for investigating soil and rock properties. The work will use selected tunnel constructions as application examples. The prediction model will provide information about rock mass and quality, and uncertainty in these parameters.

The work involves application, adaptation and development of software to interpret measurement data, by building models of the underground structure. The aim is to

build objective and reproducible models of the ground properties, by weighting information from various types of investigation method as optimally as possible. Drilling and other penetrative investigations only give spot information; geophysics can give two-dimensional and three-dimensional models, but these include uncertainties. By combining data from various geophysical and non-geophysical methods, the uncertainties may be reduced, allowing more reliable models to be developed. Methods for predicting technical parameters of rock construction using the geophysical models is also part of the work. Methods and algorithms developed will be calibrated and evaluated in relation to synthetic model data and

measurement data from actual tunnels. The work on interpretation software is based on existing algorithms in collaboration with leading groups in our international research network.

The work also includes field measurement to collect data from relevant geological environments in connection with planned construction of tunnels or rock caverns. Collected data will be used to test and calibrate the methods developed. The project team also includes Marcus Wennermark, Nils Rydén, LTH; Esben Auken, ÅU; Thomas Günther, LIAG and Robert Sturk, Skanska. The project is part of TRUST 4.2, with funding from BeFo, SBUF/Skanska, LTH, LIAG, and ÅU. ◆

Integrated use and interpretation of data from geophysical and non-geophysical methods for planning and construction in rock Marcus Wennermark, Torleif Dahlin, Lund University

Field measurements for collection of seismic data ahead of the ESS project in Lund.

Torleif Dahlin

Geoelectric monitoring in pre-investigation studies for underground infrastructure in urban environments Sara Johansson, Per-Ivar Olsson, Torleif Dahlin, Lund University

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THE AIM of the project is to develop two unique systems intended for use particularly in urban environments, where noise levels in both seismic and

electromagnetic data are normally high. These systems could provide a much clearer picture of geological structures and mechanical properties under the ground surface than existing systems. The two systems are: (1) a seismic multicomponent landstreamer system, and (2) a radio-magnetotelluric (RMT) system adapted for urban environments and for measurements in lakes. The two systems are optimised to collect

data faster than usual, but with a high resolution for structures under the surface. The systems can be used, for example, to map fracture zones, faults, fracture orientation (anisotropy), dykes, rock types, depth to the rock base, rock base quality, and sediments above the rock base. Analysis methods and application of the systems will be developed to maximise information from collected data.

A landstreamer system has been manufactured, comprising 80 3C (three-component) digital sensors. The landstreamer has been tested at two sites in Sweden: at Laisvall in the north, and at the first access ramp to the Stockholm Bypass, at Johannelund. Two doctoral students were on site and participated in the seismic fieldwork, and are now processing the data collected from the two sites. Preliminary results

were presented at the TRUST Workshop 3, which was arranged by KTH and BeFo in Stockholm on 3 February 2014. In addition to the analysis of collected data, a seismic source is being developed that will supplement the landstreamer.

This project is part of the TRUST project, and is financed through BeFo and Formas in the GeoInfra call. ◆

Multicomponent seismics and electromagnetics Bojan Brodic, Suman Mehta, Alireza Malehmir, Uppsala University

THE REAL Time Grouting Control Method (RTGCM) was developed at KTH and Chalmers. The method is a tool for controlling the spread of grouting agent in rock and controlling rock uplift. It reduces both the time taken and consumption of grouting agent, compared with current methods. The method is new, and it must be verified in the field, which is another aim of the project.

The first part of the project is aimed at verifying RTGCM in the field; it started in January 2014, and is expected to be completed in 2015. The second part is focusing on penetration

UNDERGROUND FACILITIES affect surrounding environments, mainly hydrogeological conditions, but the geochemical state is also affected in the interaction between facilities and surrounding host rock. During and after blasting, other factors should be considered, such as construction materials. The functionality of material, interaction between material and groundwater, and durability of material are all strongly influenced by the underground environment, with groundwater as the transport

medium between the surroundings and the materials. Construction materials are often cement based, such as shotcrete, or steel for components such as rock bolts.

Using coordinated studies based on hydrochemistry, the effect on primarily cement-based material and corrosion of steel bolts is being studied. The overall objective is to further develop standards to meet functional requirements at underground facilities with respect to the chemical environment in terms of groundwater chemistry and atmosphere composition. Another aim is to provide a basis for constructing safer tunnels with cost-effective maintenance.

Funding for the project is through Formas and the GeoInfra call, and is part of TRUST, in which BeFo is involved and funds part of the project. Other funding bodies are Elforsk, SKB, SBUF and Cementa, and other support is provided by Swerea KIMAB, CBI/SP, NCC, Besab, NOVA, the Swedish Transport Administration, Thomas Concrete Group and SGU. The project will continue until 2018. ◆

Real Time Grouting Control Method for rational tunnel construction, with emphasis on penetrability and spread of grouting agent Ali Nejad ghafar, Almir Draganovic KTH

Development of standards for functional requirements at underground facilities with respect to the chemical environmentFredrik Mossmark, Lars O Ericsson, Chalmers

The landstreamer has been tested at two sites in Sweden; here, at Johannelund, Stockholm.

Research projects started in 2013

Almir Draganovic

Fredrik Mossmark

Ali Nejad ghafar

Alireza Malehmir

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A COMMON perception is that increased confinement of a blast increases the level of vibrations. Is there a physical explanation for this, or is the perception unfounded? A common measure to counteract high levels of vibration is to change the drilling plane in the hope of reducing the level of confinement. Is this correct? Production

shutdown because of excessive vibrations increases costs and causes delays. The aim of the project is to investigate whether confined charges affect vibration levels in blasting. The project is in two stages: a pre-investigation study (described

here), which may be followed by field experiments. The project started with an extensive literature study by Swebrec at LTU. The study produced no clear conclusions, and there is clear disagreement on whether confinement is important for the vibration level.The project has also studied a number of cases of misfired blasting in Sweden, both tunnel blasting and bench blasting. The blasts have been analysed in terms of charge quantities, distance and vibration levels. In these blasts, no clear evidence has been found to prove that vibration levels increase with the degree of confinement. Evaluation of these blasts continues, and a final report of this pre-investigation study is expected at the start of April 2014. The pre-investigation study was funded by BeFo. ◆

Importance of confinement on vibration levelBengt Niklasson, Geosigma. Mats Olsson, EDZ-consulting

Assessment of inflowing water quantity ahead of tunnel construction – Seismoelectrics Stage 3 Peter Ulriksen, Lund University

THE AIM IS to investigate whether the seismoelectric effect can be used to predict inflowing water quantity ahead of tunnel construction. When a seismic wave is transmitted downwards and meets a water-conducting

zone, fracture or crush zone, the water is forced into motion. Because water is an electrically polar molecule that orientates itself beside the solid material, an electric current will develop in this movement. This current can be detected from the ground surface, and this gives information about the existence and depth of the zone, assuming that the speed of the seismic movement is known. The main problem is that this current is very weak, and must be measured against a background of electrical disturbances.

Stage 1 of the project was a literature study, and Stage 2 comprised background measurements along the Hallandsås Tunnel and along the planned route of the Stockholm Bypass. Stage 2 also included developing a simulator.

Stage 3 of the project, the current stage, is co-funded under GeoInfra by BeFo and Formas. The work is concentrating on

studying the central project ideas. A simulator will be used in a borehole to confirm the existence of an electrical signal in the ground. Detection algorithms can then be developed, which would be difficult if it was uncertain whether there was a signal to detect. Finally, the developed detection algorithms will be used in measurements of a real seismic source.

A discussion has been held with a Danish consulting firm, Ramböll, about using their seismic vibrator for experiments, and the company is positive. An EU application is currently being coordinated for a seismoelectric project, SELTHEX.

Seismoelectric measurements from tunnels is attracting a lot of interest. The seismic energy must be generated differently in a tunnel with an exposed rock surface than against a ground surface covered with soil. Experiments from tunnels will probably be carried out during 2014. ◆

Research projects started in 2013

properties of grouting agent in a long column of varying widths. Previous research shows that this method is more suitable than current methods. The project began in June 2013 and will run for four years. Two important stages, currently taking place, are finding suitable sites for the field experiments and manufacture of test equipment.

The project is under the TRUST umbrella, and is co-funded through BeFo and the Swedish Transport Administration within GeoInfra and the SBUF. The final report is planned for 2017. ◆

Seismoelectric simulator developed in Stage 2 of the project.

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RODS ARE used as structural elements in a number of applications, such as in engines, reactor tanks, and turbines. Within infrastructure, rods are used, for example, as

railings and bridge components, and in the rock engineering sector, as reinforcing rock bolts.

The aim is to develop a technology and a prototype by which loading on fitted rods, such as rock bolts, could be determined using two-way ultrasound. If the loading could be measured, the quality of the bolt could be determined, not only during fitting but also for older bolts that are already in place. In this way, degradation of bolts could be determined, which could ensure safety in older rock caverns. Such a method would give a direct indication of which and how many rock bolts would be needed for reinforcement, and determine how long a rock cavern is safe without requiring further measures.

There are currently no known products that use the two-way technology. A project like this, involving successful field experiments, would be unique and would attract great international attention because of the potentially broad area of application.

The aim is to develop a method for measuring tension in loaded rods, primarily in very critical rods, as part of periodic maintenance. The method will also be used to verify production methods. The method is based on two-wave technology (Bi-wave). This consists of two types of ultrasound waves, transversal and longitudinal, where the time of each echo is measured. The advantage of using two different waves is that they are affected differently by tensions in the material. The relationship between these times allows the tension in the studied material to be determined. Another positive aspect of this method is that it requires no knowledge about the length of the object being measured.

A prototype instrument, consisting

of both hardware and software, will be developed in close collaboration with instrument manufacturers and end-users. The results will be evaluated, both in the laboratory and in the field. The goal is that the rock bolts could be dimensioned and used optimally, and that older structural elements can be assessed to ensure that existing underground structures are safe.

Instrument manufacturers, sellers, and end-users are expected to benefit greatly from the results. Participating organisations are the research institute Swerea KIMAB, LTU, the Swedish Transport Administration, Atlas Copco and ÅF. The project is funded by BeFo and Formas under the GeoInfra call, and is expected to run until 2016. ◆

Evaluation of loaded structural components Peter Lundin, Swerea KIMAB

Research projects started in 2013

IN INFRA-STRUCTURE projects, groundwater drawdown is common in both construction and operational phases, as a result of construction below groundwater level.

In areas with subsidence-sensitive soils, the risk of subsidence as a result of groundwater drawdown must be carefully considered. The potential cost of extensive subsidence is very high, and the problem may also be

exacerbated by climate change.The overall objective of the project is

to develop a method for value-of-information analysis (VOIA), regarding the extent to which geotechnical and hydrogeological investigations and other measures are necessary. VOIA is a comparison of the reduced economic risk of inappropriate decisions with the cost of performing investigations and measures that reduce the risks. Consequently, methods must be developed for probabilistic groundwater and subsidence modelling, together with economic assessment of consequences.

This trans-disciplinary project will

provide novel knowledge on how to integrate existing theory on VOIA with probabilistic modelling and risk management of groundwater drawdown in rock and subsidence. The research is expected to give new insights into how to predict the risk of subsidence caused by groundwater drawdown. More accurate risk analyses will improve the efficiency of decision-making, reduce the cost of risk reduction measures, and improve communication of the risks to stakeholders, agencies and contractors.The project is co-funded by BeFo and Formas within the GeoInfra call, and SBUF, COWI, SGU and Chalmers. ◆

Risk management of groundwater drawdown in subsidence-sensitive areas.Cost-benefit analysis of safety measures in infrastructure projects.Jonas Sundell, Lars Rosén, Chalmers

Ultrasound signal from piezo-probe (1 MHz) on a 1-m bolt. Left: response from the S-wave. Right: response from the P-wave. Two clear echoes can be seen; the second echo has passed through the bolt four times (4*1m=4m). The signals are the result of 20 mean values.

Lars Rosén

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LIFE-CYCLE costs (LCC) are used in investment assessments, and aim to incorporate all costs arising through the service life of a product.

In this project, LCC of water evacuation and rock reinforcement systems is studied. The aim is to include all costs, i.e. even indirect societal costs, and see how various cost items affect the result. The study has been

carried out at a general level, showing

which factors are important to include in an LCC analysis.

The LCC of five different systems for water evacuation and rock reinforcement were calculated in four different tunnel environments in terms of investment cost, maintenance, and effect on traffic in high- and low-density situations. Future costs have been discounted using an interest rate according to recommendations given by ASEK (the working group for socio-economic calculation and analysis methods in the transport area).

The results of the study show that costs arising in conjunction with maintenance – direct costs and indirect costs arising from the effect on traffic – may be as large as or larger than the investment cost.

The study also shows that, in the tunnel environments considered, rock properties are not significant. Systems for water evacuation and

reinforcement can therefore be analysed early in the process, even if the systems are not fully designed.

The final report of the project, which is funded by BeFo, will be completed in 2014. ◆

LCC analysis of water evacuation systems and rock reinforcement Magnus Eriksson, SGI. Martin Edelman, Ramböll Sverige

Magnus Eriksson

Martin Edelman

THE SUBJECT is the ability of concrete to withstand vibrations and shock waves from, for example, blasting. The doctoral project focuses on young concrete, both

cast and sprayed, and is a continuation of an earlier licentiate project (presented in May 2012) focusing on shotcrete and vibrations from blasting in hard rock. The current project was started at the beginning of 2013; the study is now broadening to also include cast concrete, to allow comparison with shotcrete.

The focus is on conditions and applications relating to construction of facilities, such as tunnels, in hard rock. The work involves testing, and analytical and numerical modelling through comparisons between field

measurements, laboratory experiments and calculations using the finite element method. A small series of laboratory experiments in model scale is being carried out at the Concrete Structures laboratory at KTH. The objective is to increase practical knowledge about concrete and vibrations, and provide

information for better guidelines on the use of both cast and sprayed concrete in environments exposed to vibrations. The project is supervised by Professor Anders Ansell and will continue throughout 2014. The project is financed by BeFo and SBUF. ◆

Damage to concrete exposed to vibrationsLamis Ahmed, Anders Ansell, KTH

One of the five systems studied, a drained concrete lining.

Calculation results with the finite element method. Tensions around the front of a tunnel sprayed with concrete (shotcrete) in conjunction with blasting.

Lamis Ahmed

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THE AIM IS to investigate and understand why boreholes can leak despite grouting. One way is to describe how the hydraulic gradient affects the grouting agent and the size

of groundwater gradients that can be managed.

A long-term field test has now been completed. The leaking borehole in the Telia Tunnel in Gothenburg (where previous BeFo projects have been carried out) has now been sealed after four grouting attempts. During post-grouting of part of the tunnel in 2009,

it was discovered that one particular borehole was the cause of the problem. After unsuccessful regrouting and plugging, the borehole was redrilled in 2012 to investigate the problem in detail. Using two different methods – hydraulic measurements and unsuccessful but controlled grouting – the hydraulic gradient could be observed from two directions. The hydraulic measurements showed the gradient to be 60 m/m, and the controlled grountings showed 60-80 m/m. Converted to shear forces from the water, this gives 20-40 Pa. In the final grouting, the silica sol could be kept at a lower temperature, and grouting continued until gel time, which corresponds to approximately 60 Pa in

shear strength at the end of the grouting.

Future work involves analysis to find out why this succeeded, and how the information can be used at an early stage of project planning. Initial contacts have been made with SKB to observe and review the current status of the leaking TASS tunnel (a tunnel in the Äspö laboratory). Continued observations will be made in the Telia Tunnel in Gothenburg, in approximately 70 newly-drilled bolt holes.

The project has been co-financed by BeFo, Formas through the GeoInfra call, SBUF, Sven Tyréns Stiftelse (STS), and TeliaSonera. The project will continue until 2015. ◆

Research projects started in 2013

GROUTING IS used to seal tunnels and rock cavities against inflowing water, and to reduce or prevent groundwater drawdown. The work is expensive and often

comprises a significant part of the time involved in underground projects. Grouting usually involves injection of cement-based suspensions, which are pumped through drilled holes in the rock, and forced into the cracks using specially designed equipment. Research in Sweden in this field is pioneering, but the results have not yet been fully implemented in practical application.

The flow properties of the grouting agent provide fundamental input data for the models that have recently been developed for planning and steering a grouting process. However, no measurement methods can continually provide information about the properties and their changes over time. Furthermore, many traditional measurement methods are too sensitive to be used in a challenging tunnel environment, and they cannot be used

directly ‘in-line’ on the grouting rig.

Flow properties of the grouting agent have been measured with a new method based on ultrasound. The method is called UVP+PD (Ultrasound Velocity Profiling + Pressure Difference), and is based on measuring both the velocity profile and pressure drop. A major advantage is that the velocity profile in hoses and pipes can be directly measured and visualised, continually ‘in-line’. Viscosity and the flow boundary are then determined using rheological models, such as Bingham and Herschel-Bulkley, and without models in the gradient method.

Results have shown that the ultrasound method can be used for continual measurement of flow properties and how they change over time, on commonly used grouting agent and water-cement ratios. The method also works very well for determining flows, even very small flows.

The ultrasound measurement method has been developed by the food industry, and the experiments have been carried out at SIK, the Swedish Institute for Food and Biotechnology in Gothenburg. The supervisors are Ulf Håkansson at KTH and Skanska and Johan Wiklund at SIK.

The measurement equipment is now available as a commercial product (www.flow-viz.com), ready for implementation. The project is financed by BeFo and SBUF and is planned to continue throughout 2014. ◆

Monitoring properties of grouting agent with ultrasound in real timeMashuqur Rahman, Ulf Håkansson, KTH

Leaking of boreholes after grouting. Consequences and how to avoid the problems. Johan Funehag, Chalmers

Velocity profiles measured at different flow velocities, using the UVP method.

Mashuqur Rahman

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THIS PROJECT is part of the Swedish Transport Administration project on efficiency, PIA, Productivity and Innovation Development in the Construction Industry. PIA projects are aimed at facilitating the decision-making process in the proposal and investigation phase, and clarifying and improving efficiency in the implementation process.

The overall objective is to shorten the time for pre-grouting in the rock construction cycle by using more grouting pumps, with more hoses per pump, simultaneously, multiple-hole grouting.

The ultimate goal is to develop a completed model for multiple-hole grouting. System requirements for the equipment needed could be produced

at the end of the project, together with a description of the advantages and disadvantages of multiple-hole grouting.

Field experiments have been carried out at the City Line underground station, Odenplan, in Stockholm, and will be evaluated and reported in 2014. The project is financed through BeFo. ◆

THE FIELD exposures were started in September 1997, and the experiments were evaluated after 1, 2.5, 5 and 10 years. The assessments investigated the status of the test samples with fibres that cross cracks after long-term exposure. Another parameter to study is the effect on bearing capacity and chloride penetration (if applicable) in the exposed shotcrete samples.

The field exposures were carried out at three sites parallel with the laboratory test environment (20°C and 65% RH): Road no. 40: Borås – outdoors, along the motorway, DAL: Dalälven, Älvkarleby – outdoors, test samples partly buried, EUG: Eugenia Tunnel, Stockholm - road tunnel.

The results from the various assessments have been continually reported, both in Sweden (e.g. SveBeFo Reports no. 69 & 88) and internationally at various conferences. The experiment setups are being retained to

allow future assessment of the test samples, which are now unique, even internationally.

The project will continue until 2017. ◆

Field experiments for multiple-hole grouting. Improving efficiency in the grouting process. Björn Stille, Sweco

Field exposure with cracked shotcrete Per-Erik Thorsell, Vattenfall Research & Development

Test samples along Road 40, Borås

GROUTING OF rock tunnels normally involves continual pre-grouting, and very rarely is needs-based grouting applied in the construction phase. However, sealing could be more efficient by minimising grouting along sections where inflow is expected to be acceptable. Instead, the focus could be on greater sealing in areas with greater inflow and where there is greater risk of impact on the surroundings.

The objective is to investigate how needs-tested grouting

could be implemented in Swedish rock tunnel projects, and to develop a method for deciding whether needs-tested grouting can be applied in a tunnel project. This is an introductory study with focus on infrastructure tunnels, but the results could be applied to other types of underground projects.

The proposed method will be applied in 3-4 selected infrastructure tunnels in Sweden and Norway. The method is based on a somewhat different pre-investigation strategy that allows prediction of how much grouting is needed to manage the inflow requirements stipulated in the water-rights application. This prediction will then be compared with actual grouting and measured inflow. The reference tunnels will also be used to exemplify how grouting decisions can be made in Swedish and Norwegian tunnel projects.

The project started at the end of 2013 with a literature study. Data is being collected and analysed for the reference tunnels. The final report of the project is planned for June 2014. The project is financed by BeFo. ◆

Needs-tested grouting Peter Wilén, Magnus Zetterlund, Sara Kvartsberg, Norconsult

Peter Wilén Magnus Zetterlund Sara Kvartsberg

Current research projects

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TODAY, FRACTURES down to approximately 70 µm can be grouted using a cement-based grouting agent. Research has shown that it is the finest particles in the cement, between 0 and 4

µm, that flocculate and prevent penetration to fractures under 70 µm.

A new and more efficient grinding and sieving process has been developed, which makes it possible to make a cement that contains only a small quantity of the finest particles. The aim was to develop a grouting agent based on a cement that would, in principle, only contain particles between 4 and 15 µm. This cement could be used for grouting fractures down to 30 µm.

Reference penetration measurements with UF12 cement and

INJ30 have confirmed earlier research results that INJ30 has better penetration properties despite a greater d95. Penetration measurements with specially ground cement made from INJ30 and UF12 showed that penetration was no better, despite the reduced quantity of fine particles. Penetration measurements with specially ground cement made from another Portland cement showed better results, and could penetrate a 50 µm column as well as INJ30. This means that it is not only the grain curve that is important, but also the chemical composition. More research is needed to investigate

whether there is any difference between these two Portland cements.

The project started in the middle of 2012 and ended in December 2013. The final report is currently being prepared, and will be published in a BeFo report in 2014. The project has been financed by BeFo and Formas through the GeoInfra call. ◆

Improving the penetrability of cement-based grouting agent by optimising the grain curve of the cementAlmir Draganović, KTH, Conny Björk Nauplion AB and Sicomant AB

Current research projects

THE AIM IS to study various areas of application of the observational method, which is approved by Eurocode to verify the limit states of rock constructions (e.g. bearing

capacity). The method enables the rock designer, during the construction period, to adapt the design to the actual conditions, if observations of the behaviour of the structure indicate that changes are needed. In order to avoid assumptions, the work proceeds according to action plans established in advance.

Probabilistic design has great potential as a tool when the observational method is applied, because the aim is to reduce

uncertainty about the ground properties, thereby reducing the spread of the parameters. Investigating how and under what conditions probabilistic design can be linked to the observational method comprises a major part of the project.

During the year, a sub-project was completed concerning the conditions under which observations of pore pressure under concrete dams are suitable for use in assessing the safety of the dam. A new sub-project was started that is investigating how to calculate safety margins in a structure built according to the observational method. A licentiate seminar is planned for March 2014, and the project will be completed in 2015. The project has been co-funded by BeFo, Formas and the Swedish Hydropower Centre, SVC. ◆

The observational method and probabilistic design in constructions in and on rock Johan Spross, Fredrik Johansson, KTH

Pore pressure under a dam can be reduced by drainage.

PSD of SP4, SP5, UF12 and INJ30 measured with Matstersizer 3000 in AIR.

Almir Draganović

Johan Spross

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THE RESULTS will hopefully provide understanding of the rock mechanical problems that arise from tunnel fires and subsequent rescue actions. The project is in four parts: (i) Heating of test samples that are then studied using microscopes and rock mechanical tests; (ii) Heating of model tunnel to temperatures that represent a tunnel fire; (iii) Numerical analyses of model experiments; and (iv) Analysis using acoustic emission. During the year, analyses of the tests and the numerical analyses have improved understanding of the processes that lead to damage and cracking.

Project team: Christine Saiang and Ganesh Mainali (doctoral students), Erling Nordlund, Savka Dineva (supervisors), Ping Zhang (researcher) and Puria Taleghani (student). The project is planned for completion in 2014 and co-funders include BeFo and Formas. ◆

Effect of tunnel fires on stability of tunnels in hard rock in Sweden Christine Saiang, Ganesh Mainali, Erling Nordlund, Savka Dineva, LTU

THE OVERALL objective of this project is to investigate reliability and value of studies carried out before and during the construction phase when the observational method is applied. The project focuses on how decision-makers can apply a continual updating process with regard to investigations in a project. By developing a value-of-information analysis, the study examines how investigations can be made more cost-

effective and how decision-making in situations where there are great uncertainties can be made more structured and transparent.

A study was carried out of how expertise can be used for probability assessments in value-of-information analysis. A workshop was arranged with experts from the sector, where the method was tested in practice. The project is in the form of a doctoral project at Chalmers with Lars O. Ericsson as principal supervisor. The final report will be completed in spring 2014. The project has been financed through BeFo. ◆

THIS STUDY is mapping the important mechanical properties of shotcrete. Work involves laboratory investigations of the structure of the material and the mechanisms that

steer the development of the main material properties, including bonding to the rock.

The aim is to develop knowledge for production-adapted, cost-effective and safe design of rock reinforcement. The project is supervised by Anders Ansell and is planned for completion in spring 2014. The project has been co-funded by BeFo, Formas, the Swedish Transport Administration, and SBUF. ◆

Characterisation of rock; reliability in investigations of geology, fracture systems, rock quality and hydrogeological propertiesMiriam Zetterlund, Lars O Ericsson, Chalmers

Investigation and development of material properties in shotcrete for rock tunnels Lars Elof Bryne, Anders Ansell, KTH

Sample for testing adhesion between hard rock and young shotcrete.

Completed projects 2013

THE RELATIONSHIP between rock mass deformation and initiation of failure on the boundary of an underground excavation was studied. Input data comprised failure observations and measured deformations, with information from laboratory tests and underground constructions. Field data was used as input data to the numerical analyses.

The various failure mechanisms

develop differently. The failure process that leads to spalling failure occurs very rapidly, while bending and shear failure develop relatively slowly. Wedge behaviour can be monitored with the right type of instrumentation, but deformation is small before the movements that lead to instability. Monitoring data from extensometers, total stations, convergence measurement, and borehole filming,

combined with appropriate numerical analyses, can be used to detect failure and identify spalling, bending, shear and wedge failure.

The supervisor was Prof. Erling Nordlund, LTU. The project was reported in a doctoral thesis in December 2013, in several articles published in journals, conference papers, and in BeFo Report no. 130, 2013. ◆

Deformation and failure of rock Kelvis Pérez, Erling Nordlund, LTU

Miriam Zetterlund

Lars Elof Bryne

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Completed projects 2013

VARIOUS STRATEGIES were studied for interpreting, describing and communicating geological and hydrogeological information, both in early and late phases of tunnel projects. The work included presenting a framework for geological prediction that

focuses on descriptions of the water-conductive fracture system, primarily with application for grouting design. The aim was to facilitate development of conceptual models that focus on the water-conductive properties of the rock.

This was a doctoral project at

Chalmers, with Associate Professor Åsa Fransson as principal supervisor. The project was co-funded by BeFo and Formas. A licentiate thesis was presented in June 2013, and the work is reported in BeFo Report no. 125, 2013. ◆

ROCK BOLTS of carbon steel, galvanised carbon steel, galvanised and epoxy-coated carbon steel, and rust-free steel are used for rock reinforcement. Specifications today sometimes require a technical service life of more than 150 years. There is

uncertainty about the corrosion-related service life of cast rock bolts where groundwater contains chlorides or where the groundwater composition is very aggressive.

The project results were based on up to two years of corrosion testing

of partially-cast rock bolts of various types exposed in the rock walls in the Muskö and Äspö tunnels. BeFo Report no. 127, 2013. ◆

THE OVERALL objective of the project was to develop a method for predicting groundwater chemical changes caused by underground construction, and the effect of the changes on the supporting main system. This improved the base for building safer tunnels, with cost-effective maintenance during operation and less impact on the surroundings. Groundwater chemical

changes are caused by inflow in underwater constructions. This inflow increases groundwater flows, one consequence of which is that water with new properties flows towards the construction.

Two field studies were carried out in railway tunnels in the implementation phase. The aim of the studies was to improve understanding of the impact of underground constructions on

hydrology, hydrogeology and water chemistry. The project report also presents results from numerical modelling, using the PHREEQC software. The work was part of a research project aimed at developing a method for predicting the changes that can be expected in an underground project, and quantifying these changes. BeFo Report no. 126, 2013. ◆

A METHOD developed in this project enabled the properties of grouting agent to be measured during grouting (in-line measurement), using ultrasound and pressure difference. The method was successfully tested on a microcement-based grouting agent. The principles were developed in collaboration with the food industry, where in-line measurement is used to identify rheological properties of pumpable materials. The work was presented in the form of a licentiate thesis in May 2013, with Ulf Håkansson as principal supervisor. BeFo Report no. 123, 2013. ◆

THE AIM was to confirm the ‘Real Time Grouting Control Method’ (RTGC) and use the theory to verify the possibility of detecting hydraulic uplift (jacking – opening of rock fractures). Empirically-based grouting design methods, and their advantages and disadvantages, were discussed. The project also reported on an analytical solution based on theoretical associations for new stop criteria on the basis of penetration length, and to control deformation in fractures/hydraulic uplift.

The work was presented in a licentiate thesis in May 2013, with Håkan Stille and Stefan Larsson as supervisors. BeFo Report no. 124, 2013. ◆

Use of engineering geological information in rock grouting design Sara Kvartsberg, Åsa Fransson, Chalmers

Corrosion tests of various types of rock bolts Bror Sederholm, Swerea KIMAB

Hydrochemical interaction with underground constructionsFredrik Mossmark, Vectura/Chalmers, Lars O Ericsson, Chalmers

In-line rheology of cement grouts – feasibility study of an ultrasound- based non-invasive method Mashuqur Rahman, Ulf Håkansson, KTH

Design approaches for grouting of rock fractures; theory and practiceJalaleddin Rafi, Håkan Stille, KTH

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HYDRAULIC TESTS in boreholes in hard rock were analysed, to investigate the proportion of water flow attributed to the largest fracture in a tested borehole section. In tunnel projects, hydraulic tests are normally carried out in entire boreholes or in sections of a certain length, such as 3 m. This provides information about the total flow in the tested

section. A common assumption is that most water originates from the largest fracture in the section; 80% is sometimes given as a rule of thumb.

The study was based on data provided by Posiva from boreholes at the Onkalo Tunnel on the island of Olkiluoto, south-west Finland.

The results did not support the view that the most water-conductive fracture generally contributes as much as 80% of the section flow. In short test sections, the largest fracture may contribute 50%; in long sections, the proportion is smaller. The study also showed interesting results about how the relationship is changed by other studied aspects, such as fracture frequency, borehole orientation, and depth in the rock.

The degree project was presented at Chalmers in May 2013, and was funded by the Swedish Transport Administration and BeFo. ◆

THE ABILITY to estimate shear strength of rock fractures is vital for analysing various types of rock mechanics problems, such as block stability, arch stability in rock constructions underground, and sliding stability of concrete dams. The issue of which

parameters determine the shear strength of fractures is therefore of great importance in rock mechanics, and views differ on whether there is a scale dependency or not.

The project examined how scale and matching affect the shear

strength of unfilled rock fractures, and was carried out through laboratory experiments. The results can help in future work by developing methods for better estimates of shear strength at in-situ scale. BeFo Report no. 128, 2013. ◆

IN DESIGN, construction and operation of rock facilities, uncertainties must be considered. Previously, more experience-based assessments were used in planning, but gradually alternative methods have been developed that involve a more

probabilistic approach. A basic Eurocode principle is to apply such an approach. The aim of this project was to introduce an alternative stochastic method in rock mechanics calculations. It links well to the needs described in the BeFo research programme, and in

particular to ‘Rock reinforcement and design of tunnels and rock caverns’. The VMEA method is described, together with other methods for various phases in design. BeFo Report no. 122, 2013. ◆

Shearing experiments for analysis of the effect of scale and matching for rock fractures Fredrik Johansson, KTH

VMEA-method for assessing uncertainties in rock engineering Pär Johannesson, SP Technical Research Institute of Sweden

SEISMOELECTRICITY analyses the seismic waves that are later converted to electromagnetic waves in a water-conductive zone. The method focuses on detecting the presence of moving water in rock, important information in today’s rock constructions. The work comprises Stage 2, following on from

the prestudy, Stage 1, that was reported in 2011 in BeFo Report no. 112. In the project, disturbances from other flow sources (background signals) were studied with two measurement points, and how these can be managed. A simulator was designed to further develop the signal

processing needed to detect and process the relatively weak seismoelectric signals in relation to background signals. The project will continue with a third stage in 2014. BeFo Report no. 129, 2013. ◆

Seismoelectrics and the presence of water, Stage 2 Peter Ulriksen, Lund University

Does one fracture dominate borehole transmissivity? Fracture transmissivity in a crystalline rock massViðir Einarsson, Anna Höglund, Chalmers, Lisa Hernqvist, Sweco Environment

Lisa HernqvistViðir Einarsson Anna Höglund

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Publications

Reports in BeFo’s own series Alm P-G, Jonsson P, Bjelm L. Site investigations - Value and benefit from a prognosis point of view at tunnel construction, BeFo Report No. 121, 2013. * Johansson, F. Influence from scale and matedness on the peak shear strength of rough rock joints, BeFo Report No. 128, 2013. *

Johannesson P, Bokesjö M, Svensson T, Jacobsson L, Olsson L, The VMEA-method for assessing uncertainties in rock engineering, BeFo Report No. 122, 2013.*

Kvartsberg S, On the use of engineering geological information in rock grouting design. BeFo Report No. 125, 2013.

Mossmark F, Ericsson L O, Norin M, Hydrochemical interaction with underground constructions, BeFo Report No. 126, 2013. *

Pérez Hidalgo K, Deformation and failure of rock, BeFo Report No. 130, 2013.

Rafi, J Y. Design approaches for grouting of rock fractures; theory and practice, BeFo Report No. 124, 2013.

Rahman M. In-line rheology of cement grouts – Feasibility study of an ultrasound based non-invasive method, BeFo Report No. 123, 2013.

Sederholm B, Reuterswärd P, Corrosion testing of different types of rock bolts, BeFo Report No. 127, 2013. *

Ulriksen, P. Assessment of water leakage in advance of tunnelling - Seismoelectrics Part 2, BeFo Report No. 129, 2013. *

Academic thesesKvartsberg S, On the use of engineering geological information in rock grouting design, Licentiate Thesis, Chalmers University of Technology, ISSN 1652-9146; No. 2013:8, 2013.

Pérez Hidalgo K, Deformation and failure of rock, Doctoral Thesis, ISBN (print) 978-91-7439-809-0, Luleå University of Technology, 2013.

Rahman M, In-line rheology of cement grouts – Feasibility study of an ultrasound based non-invasive

method, Licentiate Thesis, Royal Institute of Technology (KTH), TRITA-JOB LIC 2020, ISSN 1650-951X, 2013.

Rafi, J Y, Design approaches for grouting of rock fractures; Theory and practice, Licentiate Thesis, Royal Institute of Technology (KTH), TRITA-JOB LIC 2021 ISSN 1650-9, 2013.

Other publicationsRock Mechanics Day 2014, Presentations in Stockholm 10 March 2014, BeFo (4/13 of papers are in English) *

Einarsson V, Höglund A. Does one fracture dominate the borehole transmissivity? Investigation of fracture transmissivity in a crystalline rock mass. Degree project, Chalmers University of Technology, 2013.

Eurock 2012 Proceedings. Rock engineering and technology for sustainable underground construction, ISRM international symposium, 28-30 May, 2012, Stockholm, Sweden, BeFo and ISRM, 2012.

7th Nordic Grouting Symposium Proceedings, BeFo, ISBN 978-91-637-0878-7, 2013.

2nd Nordic Rock Mechanics Symposium Proceedings, BeFo, ISBN 978-91-637-4351, 2013.

Papers at conferences, seminars and in journals Ahmed L, Ansell A, Laboratory investigation of stress waves in young shotcrete on rock. Magazine of Concrete Research; 64(10):899-908, 2012.

Ahmed L, Malm R, Ansell A. Finite element simulation of shotcrete exposed to underground explosions. Nordic Concrete Research; (45):59-74, 2012.

Ahmed L, Ansell A, Structural dynamic and stress wave models for analysis of shotcrete on rock exposed to blasting. Engineering structures; 35(1):11-17, 2012.

Alm P-G, Jonsson P, Bjelm L, Attitudes of Swedish rock engineers towards pre-investigations. Rock Mechanics Day 2013. *

Alm P-G, Jonsson P, Bjelm L, The value of pre-investigation methods

from a Swedish perspective, EUROCK 2013, Wroclaw, Poland, 2013.

Bryne L E, Ansell A, Holmgren J, Laboratory testing of early age bond strength between concrete for shotcrete use and rock. Nordic Concrete Research 47: 81-100, 2013.

Bryne L E, Ansell A and Holmgren J, Laboratory testing of early age bond strength of shotcrete on hard rock. Tunnelling and Underground Space Technology Incorporating Trenchless Technology Research 41C, pp. 113-119 DOI information: 10.1016/j.tust.2013.12.002, 2014.

Dahlin T, Rosqvist H, Sparrenbom C, Svensson M, Auken E, Bastani M, Moberg J, Geoelectrical Imaging for Pre-investigation for Urban Underground Infrastructure, in Procs. 31st Nordic Geological Winter Meeting, Lund, Sweden, 8-10 January 2014.

Dahlin T, Loke M H, Siikanen J, Höök M, Underwater ERT Survey for Site Investigation for a New Line for Stockholm Metro, in Procs. 31st Nordic Geological Winter Meeting, Lund, Sweden, 8-10 January 2014.

Eriksson M, Edelman M, LCC analyses for drainage and reinforcement systems. Rock Mechanics Day 2014. *

Hernqvist L, Einarsson V, Höglund A, Does one fracture dominate the borehole transmissivity? Rock Mechanics Day 2014. *

Hutchinson J. Applications of LiDAR to rock engineering projects, Rock Mechanics Day 2014.

Kvartsberg S, Fransson Å, Approach for early engineering geological prognosis adapted to rock grouting design. Presented at the 7th Nordic Grouting Symposium, Gothenburg, 2013.

Kvartsberg S, Fransson Å, Hydrogeological characterisation and stochastic modelling of a hydraulically conductive fracture system affected by grouting: A case study of horizontal circular drifts. Tunnelling and Underground Space Technology, Vol. 38, pp. 38-49, September 2013.

Lindblom U, Almfeldt S. Planning of rock maintenance with a LCC model, Bergmekanikdagen 2013. *

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Rahman M, Håkansson U, Wiklund J, In-line rheological measurements of cement grouts: Effects of water/cement ratio and hydration. Submitted to Tunnelling and Underground Space Technology, 2013.

Rahman M, Håkansson U, In-line rheometry of cement based grout – Application of an ultrasound based non-invasive method. Presented at Rock Mechanics Day, Stockholm, 2013.

Rahman M, Håkansson U, In-line ultrasound based rheology – A new tool for the measurement of flow and rheological properties of cement based grout. Presented at the 7th Nordic Grouting Symposium, Gothenburg, 2013.

Olsson M, Niklasson B, Tunnelling with pump emulsion. Experiences of explosives, equipment and charging. Rock Blasting Committee Discussion Meeting, 2013.

Pérez K. & Nordlund E. Comparison between stress and strain quantities of the failure-deformation process of Fennoscandian hard rocks using geological information, Rock Mechanics and Rock Engineering. 46, 1, p. 41-51, 2013.

Pérez K. & Nordlund E. Failure process analysis of spalling failure: comparison of laboratory test and numerical modelling data, Tunnelling and Underground Space Technology. 32, p. 66-77, 2012.

Yaghoobi R J, Tsuji M, Stille H, Theoretical Approaches in Grouting Fractures of the Rock Mass: Theories and Applications, 47th US Rock Mechanics / Geomechanics Symposium held in San Francisco, CA, USA, 23-26 June 2013.

Rafi J Y, Tsuji M, Stille H, Theoretical approaches in grouting design: estimation of penetration length and fracture deformation in real time, Rock Mechanics Day 2013.

Sparrenbom C, Dahlin T, Rosqvist H, Svensson M, Auken E, Bastani M & Moberg, Geoelectrical Imaging for Site Investigation of Urban Underground Infrastructure – a TRUST project, Procs. Groundwater Days, Lund, 16-17 October 2013, SGU, Uppsala. 2p, 2013.

Recent Publications

A COMPREHENSIVE SURVEY of hydrogeology in hard rock – Hydrogeology for Rock Engineers.The Swedish edition was published in 2009 with co-funding by BeFo, Formas, SBUF, and the Swedish Construction Federation. The translation into English was funded by BeFo, SKB and Chalmers, and the project was managed by BeFo. There was keen demand for the book in 2013, and it may be ordered through the BeFo homepage. SEK 295 excl. VAT and postage. 171 pp, illustrated.

Spross, J, Johansson F & Larsson S, (In press). On the observational method for groundwater control in the Northern Link tunnel project, Stockholm, Sweden. Bulletin of Engineering Geology and the Environment. DOI: 10.1007/s10064-013-0501-8.

Spross, J, Johansson F & Larsson S, Reducing uplift pressure uncertainty with measurements under concrete dams. In Proceedings of the 81st Annual Meeting Symposium of ICOLD in Seattle, 14 August 2013, 2551-2560, Denver: US Society on Dams, USA, 2013.

Spross, J, Johansson F & Larsson S, (In press). On the use of pore pressure measurements in safety reassessments of concrete dams founded on rock. Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards. DOI: 10.1080/17499518.2013.864172.

Spross J, Johansson F, Larsson S, Use of the observational method to assess the condition of concrete dams built on rock foundations, Bygg & teknik, 1/13, 83-87, 2013.

Tengborg P, Lindblom U, Going underground in Sweden, past-present-future, Presented at the 2nd Nordic Rock Mechanics Symposium, Gothenburg, 2013.

Zetterlund M, Ericsson L O, Value of information analysis of geological investigations, BeFo, Rock Mechanics Day 2014. *

Malehmir, A Brodic, Place, J, Juhlin, C, Bastani M, Development of near surface seismic methods for urban and mining, Applications, Geophysical Research Abstracts, Vol. 16, EGU2014-1375-1, 2014, EGU General Assembly 2014.

Mehta S, Bastani M, Malehmir M, Wan S, Pedersen L, Shallow water radio-magnetotelluric (RMT) measurements in urban environment: A case study from Stockholm city, Applications, Geophysical Research Abstracts, Vol. 16, EGU2014-4196, 2014, EGU General Assembly 2014.

Proceedings of the 7th Nordic Grouting Symposium and 2nd Nordic Rock Mechanics Symposium PROCEEDINGS from the events may be ordered in printed or digital form.

The programme contained 38 presentations (including poster presentations), and these have been published in two proceedings. Order from info@befoonline.org

ON THE BEFO homepage, research reports are available for free download in PDF format. The service is free, and you do not need to sign in. Reports may also be ordered in printed form. Order from info@befoonline.org

BeFo online

(* In Swedish)

Rock Engineering Research Foundation, P O Box 5501, SE-114 85 Stockholm, Sweden. www.befoonline.org

The Rock Engineering Research Foundation, BeFo, is a project management organisation, whose research enjoys broad support from clients, contractors, consultants, researchers and society as a whole. Research results are disseminated to maximise practical benefit and application. An objective is to develop rock construction and help to build more and better rock facilities.

Our activities are aimed at researchers and others involved in rock construction and the mining industry. By working together, we can tackle future challenges.

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