Introduction of New Ground Investigation Guideline ... · PDF fileIntroduction of New Ground...

Introduction of New Ground Investigation GuidelineIntroduction of New Ground Investigation GuidelineHorizontal Directional Coring (HDC)Horizontal Directional Coring (HDC)

AGS(HK) Technical SeminarAGS(HK) Technical Seminar14 August 201214 August 2012

ByByBruce CunninghamBruce Cunningham

& Janice Tam& Janice Tam

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G4.9 – Horizontal Directional Coringhttp://www.ags-hk.org/

AGS (HK) Ground Investigation Guideline (2012)

2

3

Part ONEUse of HDC to Identify Problematic Ground

in Tunnel ProjectsBy Janice Tam

1. Introduction

2. Considerations for HDC Planning

3. HDC for Geological Model Assessment

1. Introduction

Part ONE

5

What is Horizontal Directional Coring?

Ground Investigation Technique developed in Norway, in late 80’s.

Steerable coring along the planned trajectory.

Provide continuous core sample.

Used in petroleum & mineral explorations and tunnel project.

Steerable Coring along Tunnel AlignmentSide-tracking Coring

6

Why uses HDC in Tunnel Projects?

Minimize the risk of unforeseen tunneling conditions.

Extent of problematic rock.

Natural groundwater inflow measurement.

Continuous core near the tunnel level gives a lot more information for design and for the tenderers to price than can be obtained from vertical boreholes at regular spacing.

HDC launching point can be positioned on land for core sampling seawards and under water.

Improve Ground ModelFor Reliable Assessment

Reduce Geological &Construction Risks

Vert. BH

Vert. BH

Proposed Tunnel

2. Considerations for HDC Planning

Part ONE

8

When & Where should HDC be used?

Confirmed tunnel alignment.

Preliminary Geological Model.

Target the Identified key areas of Geotechnical Hazards / Problematic Ground.

9

Specification of HDC Technique

Max. bending angle:

9 deg/30 m (R=180 m).

Max. core-run:

3 m in deviated section.

3 or 6 m in straight section.

Core diameter:

DV size (31.5 mm) in deviated section.

NQ size (47 mm) in straight section.

Hole diameter:

Typically in N-size (76 mm).

DV

NQ

Steerable Barrel

Primary steerable coring system was designed for directional coring in competent rock.

10

Typical Working Areas

HDC for ~1200 mWorks Area 25 m long & 20 m wide

HDC for ~600 mWorks Area 15 m long & 10 m wide

11

Proposed HDC Trajectory

Designer should provide the proposed trajectory to the coring specialists e.g. control points of coordinates & level.

Tolerance Envelope

Smooth launching & curvature to get optimum coring length.

As-built alignment of HDCProposed trajectory of HDCTolerance envelope

As-built corehole trajectory for recent completed Hong Kong tunnel project

12

Proposed HDC Trajectory

DV & NQ Coring within the Designed Envelope

Proposed trajectory of HDCControl PointTolerance envelopeDV coring & steering with curvatureNQ coring in straight section

13

Coring Duration

Coring length

Tolerance envelope

Field test quantity

Approx. Coring Length

Tolerance Envelope (Dist. from trajectory)

Approx. Coring Duration (Months) Remarks

300 m 2 m 2 Field tests



1200 m 8 m 6 No field test

Coring duration of HDC referring to the recent completed Hong Kong projects

3. HDC for Geological Model Assessment

Part ONE

15

What is Geological Model?

Examination of regional & local geological conditionsCharacterizes the site focusing on

Geological feature

Geomorphological feature

Hydrogeological feature

Characteristics relevant to the engineering project

To anticipate variations in material properties and boundaries in 3D.

16

Identify Problematic Ground for HATS 2A Design

HD05 HD03a

HD03

HD02

HD01

HD04

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HDC passing through inferred Fault Zone

Causeway Bay Typhoon Shelter

HD03a

HD03

18

What we found in Tai Tam Fault?

NRNR

Altered & highly chloritized, medium to

coarse grained GRANITE

Strong, dark grey, striped white, slightly

decomposed BASALT…..

Fault Breccia Fault

BrecciaSheared Granite

NR

NR

19

HDC passing through Tai Tam Fault

Granite with Basalt Dykes & Microfracturedwithin the Tai Tam Fault

Zone

Altered & highly chloritized, medium to coarse grained

GRANITE

Shear Zones

Causeway Bay Typhoon Shelter

Basalt Dyke up to 120 m long

20

GI Data for Geological Model Assessment

HD03aHD03a

Grade III-II, locally NR, locally highly fractured, altered

Granite

Grade III-II, highly altered & chloritized Granite, with local

shear zones, quartz vein and micro-

fractures

Grade II Basalt Dyke, 120 m apparent width with sheared III-IV

Grade III-II, locally sheared Basalt Dyke

Tai Tam Fault ZoneWith Consistent high

Lugeon Test Value

RockheadRockhead

•Vertical & Inclined BH –Rockhead Level

•Continuous core sample of HDC –Geology along tunnel alignment

•Lugeon Tests –Rock Permeability

•Water Inflow Tests –Water Ingress Prediction

•Lab Tests -Rock Mass Quality around tunnel level

TunnelTunnel

Potential Hydrothermal Alteration Zone along TKO-LTT

21

Granite

Tuff

HydrothermallyAltered Rocks

TKO Line

Black Hills Tunnel Incident

Altered rock in the TKO Line.Across MTRC Black Hills tunnels at about 200 m deep.Encountered unexpectedly, caused collapse & programme delay of the TKO Line.GI indicated a RH depression in the area of veins on geological map.

Information from Vertical Borehole

22

Granite

Tuff & Granite Contactat +18mPD

Tuff & Granite Contact at +69mPD

Greisenised Granite Tuff

BH offset 70mTuff & Granite Contact

at +3mPD

HDC

Information from HDC

23

HDC

GreisenisedGranite Tuff

HDCTuff & Granite Contactat about 555m depth

(+33mPD)

Granite

Tuff

Greisenised Granite& Pegmatite

24

Summary

Key of Geological Model Assessment•Estimation of Rock mass quality•Determination of rock permeability•Prediction of groundwater ingress

Engineering Parameters used for the Assessment

•Rock Types & decomposition grades•Identification of Problematic Ground•Rockhead Level•Rock mass classification (Q-value)•Rock permeability (Lugeon Value)•Lab test results

Estimation of Tunnel Construction Performance•Rates of production•Temporary support requirements•Measures to reduce inflow of groundwater

More Detailed Ground Model such as adopting the HDC Technique

with Field tests in HDC

More Reliable Assessment &Reduced Construction &

Geological Risks

25

Part TwoProject References and HDC Technique

By Bruce Cunningham

1. Project References

2. HDC Technique

3. Typical Field Tests in HDC

4. Tunnelling Though Fault Zone

1. Project References

Part TWO

27

Route 8 – Eagle’s Nest Tunnel

Road Tunnel at Construction Stage

HDD/NP/1, March 04 to Sept. 04

HDD/SP/1, Dec. 04 to Jan. 04

Tolerance envelope of 8 m radius

HDD/SP/1(550 m)

HDD/NP/1(1152 m)

28


HDC Setup at North Portal

Northbound Tunnel

Working area of HDC

Southbound Tunnel

29

Route 8 – Eagle’s Nest TunnelSite Formation at South Portal

Setting up HDC at the rear of South Portal

HDC at South Portal


30

HDD/SP/1HDD/SP/1

31

Po Shan Road Drainage Tunnel

Drainage Tunnel Design & Construction2 nos. of HDCNov. 05 to Jan. 06Tolerance envelope of 2 m radius

PS-HDC/01252 m

PS-HDC/02310 m

Tunnel Alignment

HDC along Tunnels

32


Site Setup of HDC

Working Platform for PSWorking Platform for PS--HDC01 (252 m)HDC01 (252 m)

Coring rig for PSCoring rig for PS--HDC02 (310 m)HDC02 (310 m)

33

Ap Lei Chau

Wa FuAberdeen

Sandy Bay

Cyberport

North Point

Stonecutters Island

Wan Chai East

Central

Sai Ying Pun

HD03a(795m)

HD05(700m)

HD04(1085m)

HD02(610m)

HD01(1250m)

HD03(655m)

Trajectory of HDC

HATS 2A – the Pioneer Project in Hong Kong for:First sub-sea level application with HDC.Deepest core (reaching target zone at -160mPD) with HDC.Longest continuous samples below Victoria Harbour (i.e. over 1000m from HD01 & 04).In-situ Groundwater Inflow Measurement in sub-horizontal hole under sub-sea condition.

Harbour Area Treatment Scheme Stage 2A

34


Details of HDC in HATS 2A

HDC Duration LengthLevel of

Horizontal section

Nos. of Inflow Test

Nos. of Packer

Test

Nos. of

IP Test

HD01 10 months 1250 m ~140 mPD 10 13 20

HD02 5 months 610 m ~145 mPD 4 4 4

HD03 6 months 655 m ~145 mPD 6 12 12

HD03a 5 months 795 m ~150 mPD 5 10 0

HD04 8 months 1085 m ~135 mPD 0 8 24

HD05 5 months 700 m ~135 mPD 5 9 4

35


HATS 2A – Site Setup of HDC

HDC02 at Central (610 m)HDC02 at Central (610 m)

HDC04 at Stonecutters Island (1085 m)HDC04 at Stonecutters Island (1085 m)

HDC01 at HDC01 at SaiSai Ying Pun(1250 m)Ying Pun(1250 m)

HDC03a at Cargo Area (795 m)HDC03a at Cargo Area (795 m)

HDC03 at Wai HDC03 at Wai ChaiChai East (655 m)East (655 m)

HDC05 at Kennedy Town (700 m)HDC05 at Kennedy Town (700 m)


36


37


38


39

Liantang / Heung Yuen Wai Boundary Control Point

40

Sheung Sheung ShuiShui

NE NTNE NT

BCPBCP

FanlingFanling


41

HDC1:HDC1:1,200m1,200m

HDC2: HDC2: 950m950m

HDC3: HDC3: 1,000m1,000m




HDC LayoutHDC LayoutGeologyGeologyTai Mo Shan Formation

Shing Mun Formation

• Drilling of HDC5 & 6 completed. • Others in progress.• HDC5 completed in 2 months.• HDC6 completed in 2.5 months.• Tolerance Envelope of 8 m radius.

HDC3 – Proposed length 1000 m

Tolerance envelope of 8 m radius


42

Tseung Kwan O – Lam Tin Tunnel

43

HDC: HDC: 946 m946 m

• Drilling of HDC completed in June 12.• Testing in progress.• Duration: Approx. 6 months.• Tolerance Envelope: 5 m radius.

HDC of 945 m

Tolerance envelope of 5m radius

Tseung Kwan O – Lam Tin Tunnel

44

2. HDC Technique

Part TWO

46

Coring Procedure of HDC

Set toolface -orientation and Core with Steerable Coring Tool.

Connect the innertubeand surveytool.

Read orientation and inclination.

Survey through out the bit for azimuth reading.

Peewee Tool

Extension Rod

CoringSurvey during Coring

Corhole Survey

47

Coring Procedure of HDC

• Procedure of HDC– Planning

• Trajectory along the tunnel horizontal alignment • Targeting to pass through the expected fault zones

– Coring• Steerable within planned trajectory.

– Surveying• Regular surveys to ensure the HDC remained within the planned

trajectory envelope.

Steerable Coring Barrel

Borehole surveying tool

HDC Specialist

48

49

HDC Steerable Barrel• The 3 main components of a steerable barrel

– Locking Piston – to provide a locked position for the barrel.– Packer Assembly – to maintain the toolface position during the streering

process.– Adjustable Eccentric Housing – to adjust the bending angle.

Toolface /Rolling Angle

Dogleg / Bending Angle

50

2. HDC Steerable Barrel

PACKER

CORING BIT

ADJUSTABLE ECCENTRIC HOUSING

LOCKING PIN

51

Borehole Surveying Tool

• Corehole Surveying Tool – PeeWee EMS– A miniature electronic multishot that is used

for surveying of borehole profile.– Length of 0.975 m.– Diameter of 30 mm.– To provide orientation of a borehole.

Survey through out the bit for azimuth reading.

Peewee Tool

Extension Rod

Corehole Survey

52

HDC Working Procedure

• HDC Working Procedure in HATS 2A

HARD ROCK

GROUND

A

A

PROPOSED SEWAGE CONVEYANCE TUNNEL

160m

SECTION A-A

CORING RIG

1. INSERT CASING INTO ROCK HEAD2. STEER HDC DOWN AND LEVEL OUT TO TUNNEL HORIZON 3. DRILL OUT HORIZONTAL CORING IN 50m STAGES WITH SPECIALIST

STEERING AND WITH PUMP DOWN PACKER WATER INFLOW TESTING

4. COMPLETE HORIZONTAL CORING THROUGH EXPECTED GEOLOGICAL FEATURE AND TO INVESTIGATE ALONG TUNNEL ALIGNMENT

5. COMPLETE WATER ABSORPTION TESTING WITH DOUBLE PACKER ALONG SELECTED LENGTHS OF HDC BORE

6. GROUT AND BACKFILL HDC BORE

53



HARD ROCK

GROUND


CORING RIG

54



HARD ROCK

GROUND


CORING RIG

55



HARD ROCK

GROUND


CORING RIG

56



HARD ROCK

GROUND


200m300m400m500m600m700m800m900m1000m1100m1200m

CORING RIG

57

Operation Principle

• Steerable Core Barrel

Hard RockSoft Ground

CORING BIT

ADJUSTABLE ECCENTRIC HOUSINGANTI ROTATION SHOE

LOCKING PIN

58

Operation Principle

• Non-Rotating Outer Barrel

Hard RockSoft GroundCORE BARREL &

INNER DRIVE SHAFT

ECCENTRIC BEARING

1. Non-rotating, stationary outer barrel, by packer inflation, controls the directional setting. It is for maintaining the toolface angle, i.e. the coring orientation.

59

Operation Principle

• Bending Angle


2. Adjustable Eccentric Housing to adjust the bending angle.

60

Operation Principle

• Rotating Inner Barrel


Circulation Pressured Fluid

Fixed

3. Rotating inner barrel comprises an outer casing and an inner tube for core collection.

61

Operation Principle

• Corehole Survey


SURVEY TOOL

4. Borehole profile is surveyed using PeeWee EMS, which is a survey tool of miniature electronic multishot.

62

Working Principles

• Define the trajectory and tolerance

• Straight section -Conventional WirelineCoring

• Curve section - Steerable Coring System

• Navigation by toolface & dogleg angle

• Borehole surveying (i.e. to get the azimuth and inclination)

• Steering System:– Non-rotating outer barrel: Slides in a set toolface while coring– Rotating inner corebarrel: Drive the bit– Non-rotating innertube: Collect the core

Progress Diagram for HD/01 at Sai Ying Pun

63

3. Typical Field Tests in HDC

Part TWO

65

Water Absorption (Lugeon)Test in HDC

• Double Packers for Injection Test– Conventional injection method to determine equivalent rock mass

permeability over relatively short lengths in a horizontal direction.

• Testing Section: 3 m• Perforated Pipe: 15 mm diameter• Packer: 76 mm diameter

HATS Stage 2A

66

Water Absorption (Lugeon)Test in HDC• Double Packers for Injection Test

– Conventional injection method to determine equivalent rock mass permeability over relatively short lengths in a horizontal direction.

Conventional Coring Method Wireline Coring Method

Testing Section : 2 m longPerforated Pipe:20 mm diameter

Testing Section : 2 m longPerforated Pipe:20 mm diameter


67

Water Inflow Test by PDPS

• Pump Down Packer System (PDPS)– Sectional inflows in HDC, along the proposed tunnel alignment.– Water quantity seeping naturally from the formation as a result

of pressure difference (i.e. predicting inflow during excavation)– A more realistic hydrogeological model than using the

conventional water absorption test.– To determine an effective grouting approach.

Setup of PDPS in HDC

HATS Stage 2A

68


• Testing Procedure

Proposed Proposed TunnelTunnel

HATS Stage 2A

Typical Length of Testing Section: 100 mRanging from 50 m to 120 m.

PS

69


• Operation Principle

NQ

FAULT ZONE

ROCK HEAD

PDPS

INNER PACKER OUTER PACKER

• Retrieve the core barrel string and NQ barrel

• Pump down the PDPS along the core barrel strings

70


• Operation Principle

NQINNER PACKER OUTER PACKER

INFLATION SHEAR PIN PASSAGE SHEAR PIN

FAULT ZONE

ROCK HEAD

PDPS

PRESSURED FUILD

• Apply hydraulic pressure in stepwise to break the inflation shear pin and inflate the packers

• Further apply pressure to open the passage for test

71


CASING PACKER FORMATION PACKER

FAULT ZONE

ROCK HEAD

PDPS

NQ

PACKER

PUMPFLOW METER

PUMP OUT WATER

• Insert the pump to withdraw water from the test section in a steady rate

• Change in flow and pressure at the test section are recorded

72


CASING PACKER FORMATION PACKER

FAULT ZONE

ROCK HEAD

PDPS

MECHANICAL PULL-OUT FORCE

NQ

• Slightly pull out the core string barrel to break the deflation shear pin

• Packers deflate and the PDPS is retrieved with overshot

73

Water Inflow Test in Horizontal HolePo Shan Road Drainage Tunnel

Use of:• Stopwatch• Measurement

Jar / Container

74

Water Inflow Test in Horizontal Hole


Typical Length of Testing Section: 20 mRanging from 10 m to 25 m.

Proposed TunnelProposed Tunnel


75

Impression Packer Test

• To obtain Discontinuity Data

Impression Packer

Survey ToolDeflationShear PinLanding

Shoulder

Inner Packer

Inflation Shear Pin

Overshot Head

76



Impression Packer

Landing Shoulder

Inner Packer

Rock Joint

• Retrieve the core barrel strings and NQ core barrel

• Pump down the impression packer tool

Test Section

NQ Barrel

Impression Packer

77


• 2 m long impression packer .• FlexitMultismart at the front to

obtain the orientation.• Keep the inflation pressure at

about 50 – 60 bar for 20 minutes.• Increasing to about 80 – 90 bar

that opens the last valve, inflation.• After packer expansion, fractures

will be printed on the soft material surface,

• Mark the fractures on the packer.• Copy to the wrapped plastic foil.

HATS Stage 2A

Survey Tool

Joints printed & marked on Packer

Joints copied to plastic foil

78


Packer Device with Parafilm

Reflex EzShot Instrument

• Test ingSection: 1 m.• Zero toolface on

Parafilm.• Zero toolface of the

Reflex EzShotcalibrated with the Parafilm.

• Packer & Reflex in the hole.

• Adjust Goniometeraccording to Reflex’s measurement.

• Mark the zero Toolfaceonto the rock core,

• Place rock core on Goniometer and oriented.

• Measure the oriented joints by compass.


Joints printed on Parafilm

Rock Core on Goniometer

4. Tunnelling Though Fault Zone

Part TWO

Collapsed in Tunnel

80

Leadmine Pass Fault Gouge Collapsed into the Tunnel

Tunnelling Though Fault Zone

81

SEA BED

ROCK

LEADMINE PASSFAULT

TBM

ROCK


82

SEA BED

ROCK

LEADMINE PASSFAULT

TBM

ROCK

TBM STALLED BY FAULT GOUGE

Leadmine Pass Fault

83

By-pass to TBM to enable rail mounted drills and grouting operation to Leadmine Pass Fault

Leadmine Pass Fault

84

View through heading at end of Leadmine Pass fault


85

SEA BED

ROCK

LEADMINE PASSFAULT

ROCK

TBM STARTER CHAMBER EXCAVATED BY DRILL AND BLAST


86

SEA BED

ROCK

LEADMINE PASSFAULT

ROCK

TBM REINSTATED

Thank You

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