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FOUNDATION INVESTIGATION MANUAL

ii

Preface

The preparation of the Saskatchewan Ministry of Highways and Infrastructure Foundation Investigation

Manual (FIM) was initiated in 2013 and has been developed in accordance with local geological

conditions and guidance from the Canadian Foundation Engineering Manual (CFEM) 4th Edition. The

CFEM along with the FIM is intended to become the basis for performance of the Ministry’s

geotechnical works including but not limited to site investigation, interpretation, design, monitoring,

data requirements, reporting, risk mitigation and geohazard risk management.

The FIM contains geotechnical design and construction information that is specific to the local

geological setting and is also based on the experiences gained from the past geotechnical and geo-

environmental projects in Saskatchewan.

iii

Dedication

The Foundation Investigation Manual is dedicated to the past geotechnical field and laboratory testing

staff and engineers. The historical contributions made by the Ministry’s geotechnical and laboratory

staff has provided a significant geotechnical archive that will help with our understanding of current and

future projects in the Province of Saskatchewan.

iv

Table of Contents

Preface......................................................................................................................................................... ii

Dedication .................................................................................................................................................. iii

Table of Contents ....................................................................................................................................... iv

List of Tables ............................................................................................................................................. vi

List of Figures and Illustrations ................................................................................................................ vii

List of Symbols, Abbreviations and Nomenclature ................................................................................. viii

FIM 100 INTRODUCTION ......................................................................................................................1

100.10 Use of this Manual .......................................................................................................................1

100.10.1 Use within the Ministry .......................................................................................................1

100.10.2 Use outside the Ministry ......................................................................................................2

100.20 Use of Other Publications ............................................................................................................3

100.20.1 Approval Requirements .......................................................................................................3

100.30 Design Exceptions .......................................................................................................................4

100.30.1 Design Exception Process Guidelines .................................................................................4

100.30.2 Design Exception Report Guidelines ..................................................................................5

100.30.3 Approval ..............................................................................................................................5

FIM 200 SITE INVESTIGATIONS .........................................................................................................6

FIM 300 LABORATORY TESTING ......................................................................................................6

FIM 400 INSTRUMENTATION OPTIONS ..........................................................................................6

FIM 500 INSTRUMENTATION INSTALLATION ..............................................................................6

FIM 600 INSTRUMENTATION MONITORING .................................................................................7

600.10 Standpipe Piezometer ..................................................................................................................7

600.10.1 Background ..........................................................................................................................7

600.10.2 Required Equipment ............................................................................................................8

600.10.3 Measurement .......................................................................................................................8

600.10.4 Reporting Results ................................................................................................................9

600.20 Pneumatic Piezometer ................................................................................................................11

600.20.1 Background ........................................................................................................................11

600.20.2 Required Equipment ..........................................................................................................12

v

600.20.3 Measurement .....................................................................................................................13

600.20.4 Reporting Results ..............................................................................................................14

600.30 Vibrating Wire Piezometer ........................................................................................................16

600.30.1 Background ........................................................................................................................16


600.30.3 Measurement .....................................................................................................................17


600.40 Slope Inclinometer .....................................................................................................................23

600.40.1 Background ........................................................................................................................23


600.40.3 Measurement .....................................................................................................................26


FIM 700 GEOTECHNICAL DESIGN ..................................................................................................36

FIM 800 REPORTING............................................................................................................................36

FIM 900 GEOHAZARD RISK MANAGEMENT................................................................................36

FIM 1000 REFERENCES .......................................................................................................................37

1000.10 References used in this document ............................................................................................37

FIM 1100 INDEX .....................................................................................................................................38

1100.10 Specific Information in this document .....................................................................................38

vi

List of Tables

Table 1 – Design Exception Process ........................................................................................................... 4

Table 1 – Recommended Abbreviations for Geotechnical Instrumentations ............................................. 7

Table 2 – Binding Posts and Vibrating Wire Colour Coding ................................................................... 19

vii

List of Figures and Illustrations

Figure 1 – Water Level Depth Meter. ......................................................................................................... 8

Figure 2 – Standpipe Piezometer Plot Example. ...................................................................................... 10

Figure 3 – Schematic of Pneumatic Piezometer. ...................................................................................... 12

Figure 4 – RST Petur C-108 Pneumatic Readout. .................................................................................... 13

Figure 5 – Pneumatic Piezometer(s) Plot Example. ................................................................................. 15

Figure 6 – Portable Vibrating Wire Data Recorder. ................................................................................. 17

Figure 7 – Vibrating Wire Piezometer(s) Total Head Plot Example. ....................................................... 21

Figure 8 – Vibrating Wire Piezometer(s) Temperature Plot Example. .................................................... 22

Figure 9 – Illustration of SI Casing A-axis Grooves aligned with North. ................................................ 23

Figure 10 – Digitilt Datamate, Inclinometer Probe and Control Cable. ................................................... 25

Figure 11 – Pulley Assembly (Model #51104606). .................................................................................. 26

Figure 12 – Aluminium and PVC Extension Casings (500 mm long) along with Union Coupler........... 26

Figure 13 – Illustration of Pulley Assembly for Depth Control. .............................................................. 28

Figure 14 – Cumulative Displacement Plot Example. .............................................................................. 31

Figure 15 – Incremental Displacement Plot Example. ............................................................................. 32

Figure 16 – Resultant Displacement vs. Time Plot Example. .................................................................. 33

Figure 17 – Direction of Movement Plot Example. .................................................................................. 35

viii

List of Symbols, Abbreviations and Nomenclature

Symbol Definition ABC Factors Factors on the Vibrating Wire Calibration Sheet

atm Standard Atmosphere Unit

A0 Positive A-axis reading (Slope Inclinometer)

A180 Negative A-axis Reading (Slope Inclinometer)

B0 Positive B-axis reading (Slope Inclinometer)

B180 Negative B-axis Reading (Slope Inclinometer)

ARGUS Web-Based Remote Monitoring Software

“B” Unit Hz2/1000

CFEM Canadian Foundation Engineering Manual

DAR Design Authorization Report

FIM Ministry’s Foundation Investigation Manual

ft Foot

Hz Hertz

ID Identification

kPa Kilo Pascals

m Meter

masl Meters Above Sea Level

MHI Saskatchewan Ministry of Highways and Infrastructure

Ministry Saskatchewan Ministry of Highways and Infrastructure

mm Millimeter

N North

psi Pounds per Square Inch

SP Standpipe Piezometer

SI Slope Inclinometer

Tk Temperature Correction Factor (Vibrating Wire)

Tc Current Temperature (Vibrating Wire)

Ti Initial Temperature (Vibrating Wire)

TSB Technical Standards Branch

PN Pneumatic Piezometer

VW Vibrating Wire Piezometer

FIM 100


Section: INTRODUCTION

Subject: Use of this Manual

Date Updated Page 08 October 2013 1 of 38

Date Updated: 08 October 2013

FIM 100 Introduction 100.10 Use of this Manual The Canadian Foundation Engineering Manual (CFEM) and the Foundation Investigation Manual

(FIM), when used together, form the collection of geotechnical design and construction guidelines for

roads, runways, highways and bridges under the jurisdiction or care of the Saskatchewan Ministry of

Highways and Infrastructure (Ministry).

The CFEM along with the FIM is intended to become the basis for the Ministry’s geotechnical works

including but not limited to site investigation, interpretation, design, monitoring, data requirements,

reporting, risk mitigation and geohazard risk management.

100.10.1 Use within the Ministry Because of the nature of this manual, design information may be contained in a CFEM section, a FIM

section, or a combination of both. Geotechnical design engineers must take care to ensure they are

aware of the Ministry standards that apply to a given design topic.

The following are guidelines for the use of these publications:

• If a design topic is addressed in both the CFEM and the FIM, the Ministry standard procedure

shall be to apply information from both documents in combination, unless;

o If a design topic is addressed in both the CFEM and the FIM, but the FIM contains

information that differs from the CFEM, the information in the FIM shall be taken as the

Ministry standard.

• If a design topic is addressed in the CFEM but is not addressed in the FIM, the information in the

CFEM shall be used for guidance. The normal approval authority applies. A Design Exception

Report is not required; however, the choice of values within the design domain must be justified

by the Design Engineer.

FIM 100



Subject: Use of this Manual


• If a design topic is not addressed in the CFEM or the FIM, but is addressed in another

publication, refer to section 100.20.

100.10.2 Use outside the Ministry The Ministry of Highways and Infrastructure recognizes that others may use the Foundation

Investigation Manual (FIM). The FIM is a consolidation of Ministry policies, standards and practices

specific to the local geological setting. Therefore it is not suitable for adoption by others as design code

or a set of minimum specifications.

FIM users must accept responsibility for each design produced and all associated risk of liability.

FIM 100



Subject: Use of Other Publications


100.20 Use of Other Publications Geotechnical design engineers may wish to consider information in publications other than the CFEM

and the FIM. For example, design engineers must also consult other relevant Ministry publications.

Design engineers may also consult other sources for design guidance. This is especially beneficial when

a particular design topic is not addressed in a Ministry publication or the CFEM, or when the particular

conditions warrant additional research.

100.20.1 Approval Requirements

When considering a design element based on information from another publication, the following

approval requirements apply:

• If information in one Ministry publication is contrary to information in another, the most recently

approved shall be the governing standard. Technical Standards Branch (TSB) must be informed

of any discrepancies or ambiguities.

• If a design topic is not addressed in the CFEM or the FIM, but is addressed in another

publication produced by the Ministry, the normal approval authority applies. A Design

Exception Report is not required; however, the choice of selected values must be justified by the

design engineer.

If a design topic is not addressed in the CFEM or the FIM, and is also not addressed in another

publication produced by the Ministry, any proposed design element based on that information shall be

approved by the same authority as a design exception. See section 100.30 for more information.

FIM 100



Subject: Design Exceptions


100.30 Design Exceptions A design exception is defined as any design element differing from the approved Ministry standard. See

section 100.10 for more information on approved Ministry standards.

When in the professional judgement of the design engineer a design exception is deemed warranted, the

design engineer must obtain proper approval for the recommended exception. The process outlined in

section 100.30.1 provides design engineers with guidelines for obtaining such approval. The purpose of

this process is to ensure design exceptions are formally documented, appropriately evaluated and

properly approved, as well as providing consistency throughout the Ministry and ensuring standards are

kept current.

100.30.1 Design Exception Process Guidelines The following process outlined in Table 1 should be followed for design exception evaluation and

submission.

Table 1 – Design Exception Process

Step Process Detail

1 Identify the Key Issue(s) What are the circumstances that require a geotechnical element to differ from the current standard?

2 Assess various options outside the standard

Identify options that are being considered to address the design exception.

Identify the implications associated with each option.

3 Provide Recommendations Identify the option that is being recommended.

Why was the option selected?

Consider short-term implications, long-term implications and risk management issues.

4 Assess the need for changes to existing standards

Each design exception should be evaluated by the appropriate TSB Section to assess whether current standards should be changed.

5 Submit a report for approval See section 100.30.2

FIM 100





100.30.2 Design Exception Report Guidelines Each design exception must be submitted in a Design Exception Summary Sheet. A design exception

may apply at any phase of the project; however, approved Design Exception Summary Sheets are to be

filed with the Design Authorization Report (DAR). Design Exception Summary Sheet submitted after

approval of the DAR shall be appended to the DAR upon approval. The original DAR is to be placed in

the Region files and a copy is to be sent to TSB.

100.30.3 Approval The approval of Design Exception Summary Sheet is subject to the requirements listed in the Ministry’s

Non-Financial Signing Authority Delegation document. Further to the approval requirements in that

document, all non-minor design exceptions shall be reviewed and recommended by the Executive

Director of TSB.

FIM 200


Section: SITE INVESTIGATIONS


Date Updated Page 18 November 2013 6 of 38

Date Updated: 18 November 2013

FIM 200 Site Investigations

FIM 300 Laboratory Testing

FIM 400 Instrumentation Options

FIM 500 Instrumentation Installation

FIM 600


Section: INSTRUMENTATION MONITORING

Subject: Standpipe Piezometer

Date Updated Page 24 January 2014 7 of 38

Date Updated: 24 January 2014

FIM 600 Instrumentation Monitoring This chapter is intended to provide guidance for monitoring the Ministry’s various geotechnical

instrumentation types (e.g. standpipe piezometers, pneumatic piezometers, vibrating wire piezometers

and slope inclinometers). The standard abbreviations for the Ministry’s geotechnical instrumentation

are provided in Table 1.

Table 2 – Recommended Abbreviations for Geotechnical Instrumentations

SP Standpipe Piezometer

PN Pneumatic Piezometer

VW Vibrating Wire Piezometer

SI Slope Inclinometer

The digital outputs, results and recommendations from instrumentation monitoring shall be forwarded to

the Project Manager, Regional Materials Engineer and Sr. Geotechnical Engineer, Technical Standards

Branch (TSB).

600.10 Standpipe Piezometer The Ministry’s standard for installation of standpipe piezometers can be found under Section 500.10.

600.10.1 Background Standpipe piezometers are normally used for long term monitoring of ground water elevations in

proposed cut and fill areas. Standpipe piezometers are also useful for slope stability investigations,

establishing the vertical gradient of water, ground water flow direction, permeability measurements,

monitoring the effectiveness of dewatering, water sampling and environmental monitoring.

FIM 600





Standpipe piezometers provide information on ground water levels by measuring the water level in the

pipe. The water level in the pipe represents the pore-water pressure in the soil around the filter screen

and intake zone.

600.10.2 Required Equipment The following equipment is required to record the standpipe piezometer readings:

- 50 m water level depth meter (see Figure 1) - Pocket tape measure - Keys to unlock protective caps - Screw Driver or wrenches if the protective cover is a manhole - Field book or data sheet to record readings

The operator needs to be familiar with the safe working procedures of the above equipment. The

operator must ensure equipment is in good working condition and calibrated in advance of mobilizing to

site.

Figure 1 – Water Level Depth Meter.

600.10.3 Measurement Standpipe piezometer readings are recorded in meters from ground surface. In the case of installations

in artesian conditions, the readings are taken directly from the pressure gauge.

Readings in an open piezometer pipe are taken using a water level meter. The probe is lowered down

the tube until it contacts the water, completing an electric circuit as indicated on the gauge (LED

(Reproduced from the

following DGSI Website -

www.slopeindicator.com)

FIM 600





illuminates and the beeper sounds). Hold the cable at the point at which it touches the top of the

piezometer stickup, then pull the cable out and extend it along the outside of the pipe to ground level.

The water level depth reading is then recorded by subtracting the piezometer stickup height

measurement from the reading obtained at the top of the piezometer stickup. This results in water

depths that are recorded from ground elevation and not the top of the piezometer stickup.

Note: Drilling a borehole and backfilling it temporarily changes the pore-water pressure in the ground,

so readings that are taken immediately after installation will not be good baseline readings. Recovery

of the natural pore-water pressure may take a few hours to a few weeks, depending on the permeability

of the soil. Recovery is signalled by stable readings over a period of a few days. A baseline reading can

then be obtained.

600.10.4 Reporting Results The standpipe piezometer readings shall be plotted as Total Head (meters above sea level (masl)) vs.

Time (Reading Date) as shown in Figure 2. The title of the plot shall identify the control section, project

name and borehole name. The legend shall identify the instrument ID and other relevant descriptors.

This plot could also be utilized to report the results from nested standpipe piezometers.

The plot shall also identify the elevation of the tip of the standpipe piezometer, intake zone (comprising

of piezometer screen and granular backfill) and ground elevation. Total daily precipitation (mm) data

from the closest weather station shall also be plotted on the secondary vertical axis vs. Time (see Figure

2). Excel template to create the XYY plot (as shown in Figure 2) can be downloaded from the

Geotechnical Section under MHI’s knowledge warehouse webpage

http://www.highways.gov.sk.ca/business.

The reported results will allow geotechnical engineers to see the change in total head value with time

and evaluate the impact of various factors (such as pore-water pressure, precipitation, seasonal changes,

depth of influence) on ground strength and stability.

http://www.highways.gov.sk.ca/business�

FIM 600





Figure 2 – Standpipe Piezometer Plot Example.

Ground Elevation

SP1 Tip, 436.37

Intake Zone

0

10

20

30

40

50

60

430

432

434

436

438

440

442

444

446

448

450

10-Aug-11 9-Oct-11 8-Dec-11 6-Feb-12 6-Apr-12 5-Jun-12 4-Aug-12 3-Oct-12

Tota

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(mm

)

Ele

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d (m

asl)

Time (Reading Date)

008-06-40 Tantallon Access Slide BH-6

SP1Precipitation@Rocanville

LEGEND(STANDPIPE PIEZOMETER PLOT)

FIM 600



Subject: Pneumatic Piezometer


600.20 Pneumatic Piezometer The Ministry’s standard for installation of pneumatic piezometers can be found under Section 500.20.

600.20.1 Background Pneumatic piezometers are normally used for monitoring pore-water pressures prior to construction,

during construction and post construction. Pneumatic piezometers are also useful for slope stability

investigations, establishing the vertical gradient of water and monitoring the effectiveness of dewatering.

Pneumatic piezometers provide immediate response to very slight changes in pore pressure. Pneumatic

piezometers measure pore-water pressures by means of a hydrostatic pressure cell in a plastic or

stainless steel case with a porous (ceramic, metal or plastic) disk to allow the pore water to reach the cell

diaphragm. A supply bottle of compressed gas is used to apply pressure to the cell diaphragm. When the

air/gas pressure equals the pore water pressure the diaphragm relaxes and allows the excess gas to

release. When the gas supply is shut off the pressure in the supply line is equal to the water pressure. A

schematic diagram of a pneumatic piezometer is shown in Figure 3.

FIM 600





Figure 3 – Schematic of Pneumatic Piezometer.

600.20.2 Required Equipment The following equipment is required to record the pneumatic piezometer readings:

- A pneumatic readout box compatible with the model of piezometer installed. The recommended readout for all Ministry installations is the RST Petur C-106 or C-108 (see Figure 4).

- Keys to unlock protective caps - Screw Driver or wrenches if the protective cover is a manhole - Field book or data sheet to record readings - Compressed Gas

The operator needs to be familiar with the safe working procedures of the above equipment. The

operator must ensure equipment is in good working condition and calibrated before mobilizing to site.




FIM 600





Figure 4 – RST Petur C-108 Pneumatic Readout.

600.20.3 Measurement Pneumatic piezometer readings are recorded in kPa or psi. Readings are taken using a pneumatic

readout box compatible with the sensor used. Turn on the supply tank containing compressed gas

(nitrogen or CO2). Connect the black tubing from the transducer with the quick connect couplers

provided with the equipment. Open the by-pass valve, and observe the data gauge. Once the pressure

ascent decreases or stops, close the by-pass valve and allow the gauge to stabilize. Record the pressure

reading. Bleed out the line after taking the reading. Disconnect the coupler and close the supply tank

valve. The gauge is read directly in kPa or p.s.i. The gauge reading can be converted into pressure head

by using the following conversion:

Height of Head (m) = kPa x 0.10 (Results shall be reported in m) Height of Head (ft) = psi x 2.307


following RST Website -

www.rstinstruments.com)

http://www.rstinstruments.com/�

FIM 600









then be obtained.

600.20.4 Reporting Results The pneumatic piezometer readings shall be plotted as Total Head (masl) vs. Time (Reading Date) as

shown in Figure 5. The title of the plot shall include the control section, project name and borehole

name. The legend shall identify the instrument ID’s and other relevant descriptors. This plot could also

be utilized to report the results from stacked pneumatic piezometers.

The plot shall identify the elevation of the tip of the pneumatic piezometer and ground elevation. Total

daily precipitation (mm) data from the closest weather station shall be plotted on the secondary vertical

axis vs. Time (see Figure 5). An Excel template to create the XYY plot (as shown in Figure 5) can be

downloaded from the Geotechnical Section under MHI’s knowledge warehouse webpage



and evaluate the impact of various factors (such as pore-water pressures, precipitation, seasonal changes,

depth of influence) on ground strength and stability.


FIM 600





Figure 5 – Pneumatic Piezometer(s) Plot Example.

Ground Elevation

PN403A Tip, 587.026

PN403B Tip, 600.426

0

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30

40

50

60

585

590

595

600

605

610

615

7-Apr-08 24-Oct-08 12-May-09 28-Nov-09 16-Jun-10 2-Jan-11 21-Jul-11

Tota

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(mm

)

Ele

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asl)

Time (Reading Date)

001-04 Broadview RR Overpass BH403

PN403APN403BPrecipitation@Broadview

LEGEND(PNEUMATIC PIEZOMETER PLOT)

FIM 600



Subject: Vibrating Wire Piezometer

Date Updated January 2014 16 of 38

600.30 Vibrating Wire Piezometer The Ministry’s standard for installation of vibrating wire piezometers can be found under

Section 500.30.

600.30.1 Background Vibrating wire piezometers are normally used for monitoring pore-water pressures prior to construction,

during construction and post construction. Vibrating wire piezometers are also useful for slope stability

investigations, establishing the vertical gradient of water, understanding the impact of dynamic loading

ground improvement and monitoring the effectiveness of dewatering.

Vibrating wire piezometers measure pore-water pressures by converting water pressure to a frequency

signal via a diaphragm, a tensioned steel wire, and an electromagnetic coil. The vibrating wire

piezometer is designed so that a change in pressure on the diaphragm causes a change in tension of the

wire. An electro-magnetic coil is used to excite the wire, which then vibrates at its natural frequency.

The vibration of the wire in the proximity of the coil generates a frequency signal that is transmitted to

the readout device. The readout or data logger stores the reading in Hz. Calibration factors are then

applied to the reading to arrive at a pressure head in meters.

Each vibrating wire piezometer has a serial number and a unique calibration record. Use the sensor

serial number to match the sensor with its calibration record.

600.30.2 Required Equipment The following equipment is required to record the vibrating wire piezometer readings:

Manual System - Vibrating Wire Data Recorder - Keys to unlock protective covers - Screw Driver or wrenches if the protective cover is a manhole - Field book or data sheet to record readings

FIM 600





Semi-Automatic System - Appropriate Software for downloading data from Vibrating Wire Minilogger (if each individual

vibrating wire sensor is connected to individual Minilogger) - Appropriate Software for downloading data from Multichannel Datalogger (if multiple vibrating

wire sensors are connected to multichannel dataloggers)

Fully-Automatic System - Initial setup is required to remotely link field instruments to remote web application via a cellular

modem. Currently MHI uses ARGUS web-based remote monitoring software.

The operator needs to be familiar with the safe working procedures of the above equipment. The operator must ensure equipment is in good working condition and calibrated before mobilizing to site.

Figure 6 – Portable Vibrating Wire Data Recorder.

600.30.3 Measurement The vibrating wire piezometer provides pressure and temperature data. Be sure to record both if you

want to correct readings for temperature effects. Readings are typically in Hz or B units (Hz2/1000),

rather than units of pressure. Calibration factors must be applied to convert to units of pressure. There

is also the capability of correcting for temperature and barometric pressure.

Calculating the resultant pore water pressure recorded by the vibrating wire piezometer varies depending

on how the instrument is calibrated. For example, RST piezometer calculations are based on the “B”

unit (Hz2/1000) whereas DGSI piezometer calculations are based on Hz.


following DGSI Website


FIM 600





To convert the Hz/B unit reading to units of pressure, you must apply ABC Calibration Factors listed on

the sensor calibration record. When calculating pressure always follow the instructions on the

calibration sheet provided by the equipment manufacturer.

The ABC factors are used by the Ministry to calculate pressure from vibrating wire piezometers. When

calibration factors are given in either units of psi or kPa, choose the factors for kPa.

The following equation shall be used to calculate the pressure:

Pressure = (A × U2) + (B × U) + C + Tk(Tc – Ti) Where: U is the reading in Hz or B unit (Hz2/1000); A, B, and C are ABC Factors on the sensor calibration record; and Tk is the Temperature Correction Factor; and Tc and Ti are the current and initial temperature. Note: If the vibrating wire piezometer is sealed in a borehole or buried in a fill, there is usually little

variation in temperature, so temperature effects will be small and corrections will be less important. If

the piezometer is suspended in a shallow standpipe or well, it is likely to be affected by day to day

changes and also seasonal changes in temperature. In this case, temperature corrections will be more

important.

Note: If the vibrating wire piezometer is sealed in a borehole or buried in a fill, the only pressure acting

on the piezometer’s diaphragm should be the water pressure at that depth, so a barometric correction is

not required. If you are measuring the water level in a standpipe/ well or lake/ river that is open to the

atmosphere then the pressure recorded by the vibrating wire piezometer is equal to the pressure of

water and the air above the surface of water. An additional vibrating wire piezometer could be utilized

on site to calculate barometric correction. Install another vibrating wire piezometer out in the open and

calculate barometric correction as follows:

Barometric Correction = atm – (atm+ piezometer reading*) => Barometric Correction = - piezometer reading* => Corrected Pressure = Pressure Reading + Barometric Correction

where * is the piezometer reading obtained from vibrating wire piezometer out in the open.

FIM 600





The following steps provide methodology to collect the readings in the field for different systems -

Manual System

For exposed vibrating wires taped to a post, or vibrating wires in an enclosure, remove the electrical tape

protecting the lead ends and connect wires to the data recorder (as per Table 2).

Table 3 – Binding Posts and Vibrating Wire Colour Coding Binding Posts Wire Colours VW Orange Red VW White & Orange Black TEMP Blue White TEMP White & Blue Green SHIELD Shield Shield

• Switch on the Recorder and press Enter. • At the Type prompt, choose the appropriate frequency and temperature settings. “Hz +

Thermistor” or “B Units + Thermistor” as this data is easily manipulated. • Select the 1400 – 3500 Hz range. • Record the reading in your field logbook along with units and the serial number of the vibrating

wire piezometer.

Semi-Automatic System

For vibrating wires in a protective enclosure and connected to a permanent logger box, open the

enclosure, remove the protective cap on the data port and connect the appropriate cable from the laptop

PC. Open the software LogViewer for single-channel loggers, or Multichannel Logger Software for

multi-channel loggers. Hit “connect”. Once connected, hit “download data” and when prompted to erase

existing data or append to data, always choose “Append to data”.

Fully-Automatic System

Follow instructions provided in ARGUS remote monitoring software manual to setup a new site.



FIM 600







then be obtained.

600.30.4 Reporting Results The vibrating wire piezometer readings shall be plotted as Total Head (masl) vs. Time (Reading Date) as

shown in Figure 7. The title of the plot shall include the control section, project name and borehole

name. The legend shall identify the instrument ID’s and other relevant descriptors. This plot could also

be utilized to report the results from stacked pneumatic piezometers.

The plot shall identify the elevation of the tip of the vibrating wire piezometer and ground elevation.

Total daily precipitation (mm) data from the closest weather station shall be plotted on the secondary

vertical axis vs. Time (see Figure 7). In another plot measured temperature (degree Celsius) from each

instrument shall be plotted on the secondary vertical axis vs. Time (see Figure 8). An Excel template to

create the XYY plots (as shown in Figure 7 and Figure 8) can be downloaded from the Geotechnical

Section under MHI’s knowledge warehouse webpage http://www.highways.gov.sk.ca/business.


and evaluate the impact of various factors (such as pore-water pressures, precipitation, seasonal changes,

ground temperature, depth of influence) on ground strength and stability. Ground temperature can play

a vital role in understanding the ground instability and structural issues in areas with potential for

permafrost degradation.


FIM 600





Figure 7 – Vibrating Wire Piezometer(s) Total Head Plot Example.

Ground Elevation Ground Elevation

VW-3C Tip, 459.51VW-3C Tip, 459.51

VW-3B Tip, 453.11VW-3B Tip, 453.11

VW-3A Tip, 446.41VW-3A Tip, 446.410

10

20

30

40

50

60

445

450

455

460

465

470

12-Oct-10 30-Apr-11 16-Nov-11 3-Jun-12 20-Dec-12 8-Jul-13

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(mm

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Time (Reading Date)


VW-3C (SN 12631)VW-3B (SN 12624)VW-3A (SN 12618)Precipitation@Rocanville

LEGEND(VIBRATING WIRE PIEZOMETER PLOT)

FIM 600





Figure 8 – Vibrating Wire Piezometer(s) Temperature Plot Example.

Ground Elevation

VW-3C Tip, 459.51VW-3C Tip, 459.51

VW-3B Tip, 453.11VW-3B Tip, 453.11

VW-3A Tip, 446.41VW-3A Tip, 446.414

5

6

7

8

9

10

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450

455

460

465

470

12-Oct-10 30-Apr-11 16-Nov-11 3-Jun-12 20-Dec-12 8-Jul-13

Mea

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d Te

mpe

ratu

re (

Deg

ree

Cel

cius

)

Ele

vatio

n \T

otal

Hea

d (m

asl)

Time (Reading Date)


VW-3C (SN 12631)VW-3B (SN 12624)VW-3A (SN 12618)VW-3C TempVW-3B TempVW-3A Temp

LEGEND(VIBRATING WIRE PIEZOMETER PLOT)

FIM 600



Subject: Slope Inclinometer


600.40 Slope Inclinometer The Ministry’s standard for installation of slope inclinometer casing can be found under Section 500.40.

600.40.1 Background A slope inclinometer (SI) is used to monitor subsurface ground movement and displacement. It can be

used to monitor movement in slopes and embankments, provide warning of developing instabilities, and

monitor settlement of embankments and roadway subgrades.

SI casing is typically installed in a borehole but can also be embedded in a fill or cast into concrete.

Note: The inclinometer casing shall be installed so that one set of grooves is aligned in the North

direction, which shall be labelled “N” for NORTH. This shall be the A0 axis as shown in Figure 9. (See

Section 500.40 for further information).

Figure 9 – Illustration of SI Casing A-axis Grooves aligned with North.

The SI probe consists of a stainless steel body, a connector for control cable, and two pivoting wheel

assemblies. The probe uses two force-balanced accelerometers to measure tilt along two axes; the “A”

and “B” axis. The positive direction is referred to the as the “0” axis and the negative axis is the “180”

axis. The control cable is marked with yellow bands at half meter intervals and red bands at one meter

intervals. The cable has numeric labels every five meters.

B0 B180

A0

A180

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Slope inclinometer measures progressive changes in angle of inclination of a guide casing resulting from

the movement of geohazards such as earth masses, structural deformations due to landslides and

subsidence due to construction.

Actual slope inclinometer readings are taken in arbitrary “reading units” rather than angles or deviation.

Reading units are defined as:

Displayed Reading = sinθ × Instrument Constant Reading Metric = sinθ × 25,000

The standard two-pass survey provides two readings per axis for each interval. The probe is oriented in

the “0” direction for the first reading and in the “180” direction for the second reading. During data

reduction, the algebraic difference of the two readings is found and divided by 2, since there were two

readings. Use of the algebraic difference preserves the direction of the tilt, as indicated with a positive

or negative sign and serves to counteract any offsets in the probe’s accelerometers. Observe the

equation and example values below:

A0 Reading = 359

A180 Reading = -339

Combined Reading = = 349

To calculate lateral deviation, the algebraic difference of the two readings is divided by 2, divided by the

instrument constant, and multiplied by the measurement interval (probe length.)

Lateral Deviation = Measurement Interval × sin θ

Lateral Deviation =

Lateral Deviationmetric =

The displacement is simply defined as the difference in current deviation from initial deviation.

FIM 600





600.40.2 Required Equipment The following equipment is required to record the slope inclinometer readings:

- Keys to unlock protective covers - Screw Driver or wrenches if the protective cover is a manhole - Digitilt Datamate Model #50310900 Portable Digital Indicator (see Figure 10) - Digitilt Inclinometer Probe Model # 50302510 - Slope Indicator 100 m control cable, graduated with yellow 0.5 m marks and red 1m marks. - Large pulley assembly Model #51104606 which fits 70 mm and 85 mm diameter casing (see

Figure 11) - Silicone spray or light oil - Aluminum or PVC guide casing permanently installed in the structure to be surveyed - Aluminium or PVC extension casing (500 mm long) along with union coupler (Figure 12) which

needs to be used if the on-site SI installation is flush to ground or below ground and covered with a cap.

The operator needs to be familiar with the safe working procedures of the above equipment. The operator must ensure equipment is in good working condition and calibrated before mobilizing to site.

Figure 10 – Digitilt Datamate, Inclinometer Probe and Control Cable.




FIM 600





Figure 11 – Pulley Assembly (Model #51104606).

Figure 12 – Aluminium and PVC Extension Casings (500 mm long) along with Union Coupler.

600.40.3 Measurement Upon arrival at site, lay out a tarp to set the equipment on. The equipment needed is the inclinometer

probe, the DataMate readout box, the control cable, and the pulley assembly. Some people find it is




FIM 600





useful to bring a basket or box to hold the control cable and a rag to wipe off the probe and cable after

readings have been taken.

Unlock and remove the protective cap from the casing. Attach the pulley assembly. Remove protective

caps from probe and control cable.

Align the connector key with the keyway in the probe. Then insert the connector and tighten the nut to

secure the connection. Do not over-tighten the nut, since this will flatten the O-ring and reduce its

effectiveness.

The inclinometer casing shall be installed so that one set of grooves is aligned in the North direction,

which shall be labelled “N”. This is the A0 axis (See Section 500.40 for further information).

The probe shall be drawn from the bottom to the top of the casing two times. The upper wheels of the

probe shall be inserted into the A0 groove for the first pass and the A180 for the second pass.

Note: A pulley assembly shall be used for all SI readings to assist with depth control. The jam cleat on

the pulley assembly holds the cable and the top edge of the chassis provides a convenient reference for

cable depth marks (see Figure 13).

FIM 600





Figure 13 – Illustration of Pulley Assembly for Depth Control.

To reduce likelihood of error handle the control cable consistently and accurately and align the depth

marks on the control cable with the same reference. The Ministry has historically used the cable clamps

as the reference point for measurement of SI data (as shown in Figure 13). The placements for a

particular depth should be within 5 mm of the previous reading.

Turn on the data mate recording unit. This energizes the accelerometers, making them less susceptible

to shock.

Insert the probe into the casing with the upper wheels of both wheel assemblies in the A0 groove.

(Cupping the wheels with a hand to compress the springs will help with insertion). If a pulley assembly

is being used, take out the pulley wheel, insert the probe, and then replace the wheel.

Lower the probe slowly to the bottom. Do not allow it to strike the bottom. Allow the probe to adjust to

the temperature inside the casing for at least five minutes. If this is the initial reading of the SI the

starting depth should be within about 0.5 m of the bottom of the casing.




FIM 600





If the probe is accidentally drawn above the intended depth, lower it down to the previous reading depth

and then draw it up again to the intended depth. This helps to ensure consistent probe placement.

Raise the probe to the starting depth. Wait for the numbers on the readout to stabilize. If readings do

not stabilize, record an average reading. Press the button on the DataMate to record both the A and B

axis readings. Raise the probe to the next depth. Wait for a stable reading, and then record it. Repeat

this process until the probe is at the top of the casing.

Remove the probe and rotate it 180 degrees, so that the lower wheels of both wheel assemblies are

inserted into the A0 groove. When you remove the probe, cup the wheels with your hands to prevent

them from snapping outwards. Also, hold the probe upright when rotating it.

Lower the probe to the bottom, raise it to the starting depth, and continue the survey. Take readings at

each depth until you have reached the top. Remove the probe. At this point, you may want to validate

the data set and make any corrections necessary.

Note: If this is the initialization survey, repeat the above steps to obtain two readings.

For quality assurance, the field operator should check Checksums before leaving the site. A checksum

is the sum of 0 and 180 degree readings at the same depth. For example -

A0 Reading = 359 A180 Reading = -339

Checksum = 359 + (-339) = 20

Ideally, the sum should be close to zero since the readings have opposite signs. In practice, checksums

are rarely zero. In general, the operator should look for consistency in checksums. A checksum that is

significantly different from checksums above and below it may indicate that the probe wasn’t positioned

correctly or the reading was not stable when recorded.

600.40.4 Reporting Results The slope inclinometer data shall be presented utilizing the following four plots – namely cumulative

displacement plot, incremental displacement plot, resultant displacement vs time plot and direction of

FIM 600





movement plot for the critical shear zone(s). The detail for each of these four plots is provided in the

section below.

Magnitude and Zone of Shear Movement

Changes in deviation are called displacements, since the change indicates that the casing has moved

away from its original position. When displacements are summed and plotted, the result is a high

resolution representation of movement.

Cumulative displacement plot shows a displacement profile. Displacements are summed from bottom to

top of the SI casing. As an example, ARGUS web-based monitoring software generated cumulative

displacement plot is shown in Figure 14.

FIM 600





Figure 14 – Cumulative Displacement Plot Example.

Incremental displacement plot shows movement at each measurement interval. The growing “spike”

indicates a shear movement. As an example, ARGUS web-based monitoring software generated

cumulative displacement plot is shown in Figure 15.

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Figure 15 – Incremental Displacement Plot Example.

Rate of Movement

“Another purpose of inclinometer measurements is to determine the rate of shear movement. Usually,

the shear zone is less than a few metres thick, and thus the sum of change over this zone is

representative of the magnitude and rate of the entire landslide” (Stark and Choi, 2008). The rate of

movement can be evaluated from a plot of resultant displacement versus time data as shown in Figure

16. The title of the plot shall include the control section, project name and borehole name. The legend

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shall identify the instrument ID, plotted depth and elevation. An Excel template to create the Resultant

Displacement (mm) vs Time (Reading Date) plot (as shown in Figure 16) can be downloaded from the

Geotechnical Section under MHI’s knowledge warehouse webpage


Figure 16 – Resultant Displacement vs. Time Plot Example.

The rate of movement is frequently more important than the magnitude of movement because it

determines whether or not the slide is accelerating, decelerating, or continuing at the same rate. This

0

0.5

1

1.5

2

2.5

3

3.5

10-Aug-10 18-Nov-10 26-Feb-11 6-Jun-11 14-Sep-11 23-Dec-11 1-Apr-12 10-Jul-12 18-Oct-12

Res

ulta

nt D

ispl

acem

ent

(mm

)

Time (Reading Date)


SI003(Depth 29 m/ Elev 412.3 masl)

SI003 (Depth 29.5m/ Elev 411.8 masl)

SI003 (Depth 30m/ Elev 411.3 masl)

LEGEND


FIM 600





information can be utilized for geohazard risk management and to inform the public and any third

parties involved.

Whether the slide is accelerating or moving at the same rate is also important to determine shear strength

and potential for strength loss. For example, if the shear zone is not at residual strength, strength loss

will occur with continued movement until the residual condition is reached. This strength loss

phenomenon can result in acceleration of the slide mass and progressive failure of the slope. The rate of

movement is also of importance to investigate the effect of rainfall, slope loading, toe excavation, and

remedial measures on slope stability. (Stark and Choi, 2008)

Direction of Movement

Determining the direction of movement is important to determine the cause of the slide, critical cross-

section (which needs to be parallel to the direction of movement), back calculation of shear strength

parameters, and design of remedial measures. The direction of movement can also be used to determine

if the slide is moving as a single unit or not, which can be helpful in evaluating the effectiveness of

proposed remediation options. (Modified from Stark and Choi, 2008)

As per the Ministry standard the inclinometer casing shall be installed so that one set of grooves is

aligned in the North direction, which shall be labelled “N” for NORTH. This shall be the A0 axis (See

Figure 9). Thus, the actual magnitude and direction of movement can be determined by plotting two

components of movement measured in the A-axes and B-axes as shown in Figure 17. The title of the

plot shall include the control section, project name and borehole name. The legend shall identify the

instrument ID, plotted depth and elevation. An Excel template to create the Direction of Movement plot

(as shown in Figure 17) can be downloaded from the Geotechnical Section under MHI’s knowledge

warehouse webpage http://www.highways.gov.sk.ca/business.


FIM 600





Figure 17 – Direction of Movement Plot Example.

-3

-2

-1

0

1

2

3

-3 -2 -1 0 1 2 3

A -A

xis

Res

ulta

nt D

ispl

acem

ent (

mm

)

B Axis Resultant Displacement (mm)


SI003(Depth 29 m/ Elev 412.3 masl)

SI003 (Depth 29.5m/ Elev 411.8 masl)

SI003 (Depth 30m/ Elev 411.3 masl)

LEGEND

FIM 700


Section: GEOTECHNICAL DESIGN




FIM 700 Geotechnical Design

FIM 800 Reporting

FIM 900 Geohazard Risk Management

FIM 1000


Section: REFERENCES

Subject: References used in this document



FIM 1000 References

1000.10 References used in this document

CFEM 2006. Canadian Foundation Engineering Manual 4th Edition, Canadian Geotechnical Society

DGSI Slope Indicator Website www.slopeindicator.com

Non-Financial Signing Authority Delegation Document (effective 1 April 2013)

RST Instruments Website www.rstinstruments.com

Stark and Choi 2008. Slope Inclinometers for Landslides, Timothy D. Stark and Hangseok Choi,

Landslides 2008.

http://www.rstinstruments.com/�

FIM 1100


Section: INDEX

Subject: Specific Information in this document



FIM 1100 Index

1100.10 Specific Information in this document

CFEM ....................................... ii, viii, 1, 2, 3, 37

Design Authorization Report (DAR) ................ 5

Design Exception Summary Sheet.................... 5

Displacement....................................... 31, 32, 33 instrumentation ................................................. 7

monitoring ..................... 7, 11, 16, 17, 19, 30, 31

Movement ..................................... 30, 32, 34, 35

North ................................................... 23, 27, 34

Pneumatic Piezometer ..................... 7, 11, 12, 15

pore water.................................................. 11, 17

precipitation .......................................... 9, 14, 20

Slope Inclinometer ...................................... 7, 23 Standpipe Piezometer.................................. 7, 10

Total Head ....................................... 9, 14, 20, 21

Vibrating Wire Piezometer ............. 7, 16, 21, 22

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