selecting drilling methods for the best outcome. presented by: terrence gill (stats) mathew bulmer...

Selecting Drilling Methods for the Best Outcome

Presented by: Terrence Gill (STATS)Mathew Bulmer

(MDWES)Peter Grimwood

(DIRECT PUSH PROBE)

Selecting Drilling Methods for the Best

Outcome

PROPOSED DEVELOPMENTEND USE ?

•Residential ?•Commercial ?•Industrial ?•Recreational ?•Other ?The end use will govern the depth of investigation required

WHERE IS THE PROPOSED DEVELOPMENT ?

• CITY CENTRE ?

• SUBURBS ?

• REGIONAL ?

• The loc ation will influence the information that is available

WWHAT IS KNOWN ABOUT THE SITE ? WHAT IS THE GEOLOGICAL ENVIRONMENT ?

WHAT IS THE SITE HISTORY

• IS IT GREEN FIELD?• HAS IT BEEN DEVELOPED BEFORE?

YES NO

?

Geotechnical /Environmentaloverlap

• Geological maps• Orthophoto maps• Historical Aerial photos• Site History

GEOTECHNICAL

ENVIRONMENTAL

CONTAMINATION ?FIND OUT MORE

GEOTECHNICAL ENVIRONMENTAL

DESKTOP STUDYPRELIMINARY SITE

INVESTIGATIONP.S.I.

WARNING• STAFF AND DRILLERS COULD BE AT

RISK• ASBESTOS BEBURIED IN THE

GROUND• ORGANIC OR INORGANIC CHEMICALS

FOUND• OTHER HEALTH RISKS• P.P.E. MAY BE REQUIRED

PLANNING

TYPE OF GEOTECHNICAL INVESTIGATION

• CATEGORY 1.• SMALL/SIMPLE STRUCTURES• LIGHTLY LOADED• GROUND CONDITIONS KNOWN FROM EXPERIENCE• STABILITY AND SETTLEMENT CALCULATION NOT CONSIDERED NECESSARY

• CATEGORY 2.• MEDIUM SIZE STRUCTURES• BRIDGES…RETAINING WALLS…..EMBANKMENTS

• CATEGORY 3.• LARGE STRUCTURES• POTENTIALLY DIFFICULT GROUND CONDITIONS

PREFERRED TYPE OF SAMPLING REQUIRED

Disturbed or Undisturbed

• Class 1: Disturbed• Strata identification only

• Class 2: Disturbed

• Soil Classification tests only

• Class 3: Disturbed• Soil Classification & water content

• Class 4: Disturbed or Undisturbed• Soil Classification, water content ,density

• Class 5: Undisturbed• Soil Classification, water content, density, shear strength, consolidation tests

TYPE OF GEOTECHNICAL INVESTIGATION REQUIRED

• CATEGORY 1. SHALLOW INVESTIGATIONS• TEST PITS- GENERALLY UP TO 3.0 METERS ……

• MAX 5.0 METRES DUE TO LIMITATIONS OF EXCAVATORS EQUIPMENT• ALSO GOVERNED BY THE SUBSURFACE MATERIAL

• HAND AUGERS• MACHINE AUGERS• DIRECT PUSH PROBING EQUIPMENT

• CLASS OF SAMPLE • Class 1 ,2,3, & 4.

• SIZE OF SAMPLE • VARIES ….5KGS FOR P.I.& P.S.D…………UP TO 20KGS FOR MMDD & CBR

TYPE OF GEOTECHNICAL INVESTIGATION REQUIRED

• CATEGORY 2, & 3 DEEPER INVESTIGATIONS• MACHINE AUGERS• DIRECT PUSH PROBE (DPP) & SPT• HQ3 DIAMOND CORE & SPT• ELECTRIC FRICTION CONE PENETROMETER (CPT)

• TYPE OF SAMPLE • DISTURBED• CONTINUOUS • UNDISTURBED

OPTIMAL DRILLING SOLUTIONSGEOTECHNICAL

• DIRECT PUSH PROBE ( DPP)• CLASS 1 & 2. (Shallow Investigations)• Soil & Soft Rock < 20 Mpa• DPP can add SPT or CPT

• CLASS 3 & 4. ( DEEPER Depths)• DPP with SPT or CPT (Soil & Soft Rock)• Hollow flight auger with SPT (Soil & Soft Rock)• Diamond Drilling with SPT ( Soft Rock & Hard Rock) continuous sample for UCS tests

• CLASS 5.• Diamond core with SPT ( Soft Rock & Hard Rock) continuous sample for UCS tests

Geotechnical /Environmentaloverlap

• SHALLOW INVESTIGATIONS < 5.0 METRES• SMALL SAMPLES REQUIRED FOR BOTH• DPP IDEAL

GEOTECHNICAL ENVIRONMENTAL

COST EFFECTIVE APPROACHGeotechnical & Environmental

Combine Informationfrom Desk Top Study AND P.S.I

• HSE issues identified • Acid Sulphate Soils (ASS) addressed• CAN OFTEN Use DPP for both Geotechnical & Environmental investigation and

sampling• 1 mob/demob charge• Extend DPP depths and use SPT & CPT for extra Geotechnical design parameters.

• Outcome from DPP limited by• hardness of rock and • need for continuous rock coring

BENEFITS OF Direct Push Probe (DPP)

• CAN BE USED IN BOTH GEOTECHNICAL & ENVIRONMENTAL INVESTIGATIONS

• SAVE ON MOB/DEMOB $$ • EXTEND THE DEPTH • DO MORE LOCATIONS• INCLUDE SPT OR CPT

• ONE SIZE DOES NOT FIT ALL BUT YOU WILL GET A MORE COST EFFECTIVE RESULT IF YOU CAN PLAN THE GEOTECHNICAL & ENVIRONMENTAL INVESTIGATIONS & SHARE THE SITE TIME.

SELECTING DRILLING METHODS

FOR THE BEST OUTCOME

ENVIRONMENTAL PRACTIONER’S PERSPECTIVE & REQUIREMENTS

INVESTIGATION PERCEPTIONS

There is a perception that the Geotechnical Investigation is more important than the Environmental Investigation?

Why is that ?

• They both carry equal importance to understanding the site conditions.

• Is Geotechnical data seen to be more commercially viable than environmental data?

This leaves the site developer the following scenario

• Investigating the site twice which includes:

Two mobilisation costs.

and

Two investigations within the same soil space.

WHAT IF?

What if both investigations were undertaken at the same time?

• Would this impede both investigations?

• Could the drill methods be adapted to accommodate both investigation requirements?

• Would there be a conflict of interest - two consultancies wanting the same soil sample at the same depth?

BACKGROUND DATA UP FRONT

If there was one thing we could change it would be to get clients to carry out Preliminary Site Investigation (PSI) at the planning stage up front.

Why is this ?

• Benefits the Environmental Scientist and Geotechnical Engineer.

• Provides the data to develop a Detail Site Investigation (DSI).

• Environmental impacts can be assessed and targeted.

• Develops a Conceptual Site Model (CSM) for the site.

This information at an early stage can be beneficial to geo-technical engineers and all future site investigations including the environmental scientist.

PSI INFORMATION IS GOOD INFORMATION

The PSI will provide:

Historic Land Ownership

Historic Maps and Aerial Photos.

Land use history – landfills, soil import / export

Potential contamination from land use – harmful / toxic

Dangerous goods history

Acid Sulfate Soils (ASS) risks

Geological conditions

Hydrogeological conditions - Groundwater depths and local users

All of this information helps makes informed decisions about how the site should be investigated and potential control measures required.

DEVELOPING A SCOPE OF WORKS TOGETHER

Achieving synchronised investigations in an ideal world:

• Environmental practioners and geotechnical engineers to collaborate and form partnerships.

• Joint development of a site investigation to collect data for both parties.

• Reduce any risks to site workers and visitors.

• Minimise risk to the environment.

• SAVE client time and money in duplicated works.

All before the ground is broken on the site!

HOW DEEP IS TOO DEEP?

Typically environmental investigations are concerned with the upper few metres of the soil profile.

Is this enough for the geotechnical engineer?

Would drilling depths have to be deeper to accommodate geotechnical requirements?

Could the geotechnical engineer sample the soils left?

Would soil volumes be sufficient to sample?

Does the geotechnical engineer want the same sample depth?

Would collaboration at the beginning of the project allow both parties to achieve respective project requirements?

ENVIRONMENTAL DRILLING

Environmental drilling for sampling purposes is usually undertaken via push probe methodology. This sampling method is selected for:

• Clean environmental drilling (no drill fluids).

• Soil cores which detail individual soil horizons.

• Allows installation of environmental monitoring wells.

• Efficient.

• The size of the rig allows access onto most sites.

PROS

If the Environmental Scientist and Geotechnical Engineer investigated together?

• Reduced uncertainty in tendering and quoting.

• Identify potential site hazards early.

• Identify spatial irregularities about site.

• Reduce need to remobilise.

• Identify opportunities to reduce duplication.

• Enhanced focus on chemical properties of upper soil profile.

CONS

• Conflict of issues in methodology

• Sampling depth requirements (Environmental vs Geotechnical)

• Potential contamination of samples (drilling method)

• Lost billing opportunity: real or perceptive

• Who determines objectives

• Liability

• Perceptions about experience and qualifications

SUMMARY

Site investigations require the site history, characterisation of physical properties of underlying lithology and vertical profiling of the upper soil profile.

Typically this has been achieved via a piece meal process rather than an integrated process.

Data from any investigation can serve multiple functions provided the requirements of each function are met.

No one method will meet all needs but an integrated approach via early incorporation of a PSI has the potential to save time and money.

SELECTING DRILLING METHODS FOR THE

BEST OUTCOMEFOR

GEOTECHNICAL OR ENVIRONMENTAL

DRILLING

Specialist Geo-Environmental Drillers

Geotechnical Drilling Methods

Environmental Drilling Methods

Desired Outcom

es


GEOTECHNICAL DRILLING METHODS

METHOD• DIAMOND DRILLING/TRIPLE

TUBE DIAMOND

• MUD ROTARY/SONIC

• RAB/AIRCORE/RC

• DIRECT PUSH/HOLLOW STEM AUGER/CONTINUOUS FLIGHT AUGER

DRILLING ADDITIVES• WATER/BENTONITE/POLYMERS/

LUBRICANTS/LOST CIRCULATION MATERIAL

• AIR /MUDS/POLYMERS/ LOST CIRCULATION MATERIAL/CONTAINS HYDROCARBONS

• MUDS/WATER


ENVIRONMENTAL DRILLING METHODS

COMMON METHODS• DIRECT PUSH

• HOLLOW STEM AUGER/CONTINUOUS FLIGHT AUGER

• SONIC

DRILLING ADDITIVES• WATER

• WATER

• WATER/MUDS/POLYMERS


DESIRED OUTCOMES

• SOIL SAMPLE FOR TESTING

• BULK – STRENGTH , MOISTURE ETC

• ASS - ANALYSIS

• INSITU PARAMETERS

• SPT, VANE SHEAR, CPT, SIESMIC, ETC

• ADDITIONAL EQUIPMENT DATA LOGGERS

• STAND PIPES

• GROUND WATER LEVELS, PORE PRESSURES, WATER QUALITY

GEOTECHNICAL


DESIRED OUTCOMES

ENVIRONMENTAL

• SOIL SAMPLE FOR TESTING

• CONTAMINATION, ASS,

• WATER WELLS – QUALITY, CONTAMINATION, LEVEL

• DATA LOGGERS

• SOIL VAPOUR READING/WELLS

• DIRECT IMAGE – MIP, HPT, EC, ETC


ONLY WATER WILL DO

• SOME BENTONITE BASED MUDS AND DRILLING FLUIDS CAN CONTAIN SRB.

• SRB – SULPHUR REDUCING BACTERIA

• CORROSIVE TO IRON – WELL HEADS AND DOWN HOLE INFRASTRUCTURE

• DRILL STRINGS

• CAN INTERFERE WITH ASS RESULTS

• PRODUCES H2S

• WATER WELLS REQUIRE DECONTAMINATION AFTER DRILLING

• ALTERS THE CHEMISTRY OF THE WATER

• AIR – CONTAINS HYDROCARBONS, SPREADS CONTAMINATION (ASBESTOS, BIOLOGICAL HAZARDS)

• OXIDISES AND VOLATILISES

• POROUS FORMATIONS WILL ABSORB AIR AND DISCHARGE FOR HOURS SOMETIMES DAYS AFTER DRILLING HAS CEASED

• TOOL JOINTS USUALLY LUBRICATED WITH EP GREASE CONTAINING A VARIETY OF ADDITIVES


CPT & SPT/SOIL BORE/MONITORING WELL


Joint

JOINTGEOTECH & ENVIRODRILLING METHODS

DIRECT PUSH

• VARIETY OF DIAMETER SAMPLES - 32MM UP TO 70MM (IDEAL FOR ASS, GEOTECH AND CONTAM SAMPLING)

• CAN DO SPT/CPT, VANE SHEAR, DIRECT PUSH, WELL INSTALLATION, HOLLOW STEM AUGER – SAVING TIME AND EXPENSE ON MOBILISING MULTIPLE RIGS

• VARIETY OF DIRECT IMAGING APPLICATIONS

• ONLY WATER USED IN DRILLING OPERATION – AND THEN ONLY ONCE THE WATER TABLE HAS BEEN REACHED

• ALL DIRECT PUSH SAMPLES ARE CONTAINED IN EITHER SPLIT SPOON OR SAMPLE TUBES

• RIGS ARE COMPACT AND HIGHLY MOBILE


SPT DIRECT PUSH RIGSPT/VIBRATING WIRE PIEZO INSTALLATION/OFF SHORE

WORK


Geotechnical Drilling Methods

CPT DIRECT PUSH RIGDIFFICULT SITE ACCESS


Joint

CONCLUSIONSpecialist Geo-Environmental Drillers

BOTH GEOTECHNICAL AND ENVIRONMENTAL INVESTIGATIONS HAVE THERE OWN STAND ALONE

REQUIREMENTS THAT DEMAND THE USE OF SPECIALIST EQUIPMENT .

BUT THERE IS THE COMMON GROUND THAT CAN SAVE TIME AND EXPENSE BY COMBINING PARTS OF

INVESTIGATIONS WITH THE EFFICIENT USE OF SOME DUAL PURPOSE DRILLING RIGS

PANEL SESSION

selecting drilling methods for the best outcome. presented by: terrence gill (stats) mathew bulmer...

Documents

planning slide

available slide

undisturbed class

best outcome slide

cpt class

density class

mmdd cbr slide

ucs tests class