Selecting Drilling Methods for the Best Outcome
Selecting Drilling Methods
for the Best Outcome
Presented by:
PUSH PROBE)
Terrence Gill (STATS)
Mathew Bulmer (MDWES)
Peter Grimwood (DIRECT
PROPOSED DEVELOPMENT
END 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 /Environmental
overlap
• Geological maps
• Orthophoto maps
• Historical Aerial photos
• Site History
GEOTECHNI
CAL
ENVIRONMEN
TAL
CONTAMINATION ?
FIND OUT MORE
GEOTECHNICAL
DESKTOP STUDY
ENVIRONMENTAL
PRELIMINARY SITE
INVESTIGATION
P.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 SOLUTIONS
GEOTECHNICAL
• 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 /Environmental
overlap
• SHALLOW INVESTIGATIONS < 5.0 METRES
• SMALL SAMPLES REQUIRED FOR BOTH
• DPP IDEAL
GEOTECHNICAL
ENVIRONMENTAL
COST EFFECTIVE APPROACH
Geotechnical &
Environmental
Combine Information
from 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 geotechnical 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.
Specialist GeoEnvironmental Drillers
SELECTING DRILLING
METHODS FOR THE BEST
OUTCOME
FOR
GEOTECHNICAL OR ENVIRONMENTAL
DRILLING
Specialist GeoEnvironmental Drillers
Geotechnical Drilling Methods
Environmental Drilling Methods
Desired
Outcomes
Specialist GeoEnvironmental Drillers
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/LUBR
ICANTS/LOST CIRCULATION
MATERIAL
• AIR /MUDS/POLYMERS/ LOST
CIRCULATION MATERIAL/CONTAINS
HYDROCARBONS
• MUDS/WATER
Specialist GeoEnvironmental Drillers
ENVIRONMENTAL DRILLING METHODS
COMMON METHODS
DRILLING ADDITIVES
• DIRECT PUSH
• WATER
• HOLLOW STEM
AUGER/CONTINUOUS FLIGHT
AUGER
• WATER
• SONIC
• WATER/MUDS/POLYMERS
DESIRED OUTCOMES
GEOTECHNICAL
• 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
Specialist GeoEnvironmental Drillers
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
Specialist GeoEnvironmental Drillers
ONLY WATER WILL DO
Specialist GeoEnvironmental Drillers
• 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
Joint
Specialist GeoEnvironmental Drillers
CPT & SPT/SOIL BORE/MONITORING
WELL
JOINT
GEOTECH & ENVIRO
DRILLING METHODS
Specialist GeoEnvironmental Drillers
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
Geotechnical Drilling Methods
SPT DIRECT PUSH RIG
Specialist GeoEnvironmental Drillers
SPT/VIBRATING WIRE PIEZO INSTALLATION/OFF SHORE WORK
Joint
CPT DIRECT PUSH RIG
DIFFICULT SITE ACCESS
Specialist GeoEnvironmental Drillers
CONCLUSION
Specialist GeoEnvironmental 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