Geotechnical and Tunnel Design and Construction integrated process

1. IDENTIFY & DESIGN
PROTECTION WORKS
GEOLOGICAL -GEOTECHNICAL MODEL
SITE INVESTIGATIONS (All previous data, desk
study, other project data.)
BUILDING RISK ASSESSMENTS &
PROTECTION PLANS. Allowable
Limits of Deformation
ALIGNMENT OF RAIL
TRACK & STATION
LOCATION
INSTRUMENTATION
DESIGN
SETTLEMENT ANALYSIS
Ground loss, shield loss,
tailskin loss, sensitivity
TBM OPERATIONAL PARAMETERS &
RANGE -Face Pressure, grout
pressure/volume
SURVEYS FOR UTILITIES, ID
NATURE OF MATERIAL &
ALLOWABLE LIMITS OF
GEOLOGICAL PROFILE & GEOTECHNICAL
PARAMETERS
SITE INVESTIGATIONS
Supplementary & Instrumentation
Installation
BUILDING CONDITION SURVEYS,
STRUCTURAL SURVEYS,
Confirm Extent and magnitude of
settlement, correctness of face pressure
Confirm /Reassess Geological profile and
face pressures required to ensure
settlements controlled.
Confirm or Revise Building protection
Works as required. Revise risk assessment
MONITORING
TBM Parameters
Face Pressure
Grout Volume & Pressure
Muck Volume
Thrust, torque & Advance Speed
Instrumentation
Drilling Data against geological profile
Planned against actual settlement
Monitoring of Treated Areas
Immediate Actions
Reading Frequency
Accuracy checks
Visual Inspections of surface/buildings
SAFE TUNNELLING
Controlled settlement, minimal impact on
infrastructure, optimised face pressures,
controlled progress
CONSTRUCTION
Tunnelling
TBM Operation
Face pressure,
Grouting Volume & Pressure
Muck Volume
Thrust
Torque
Speed of Advance
Steering / Survey Control
Lining Erection
Build Quality / Repars
Alignment
Ground Treatment
Drilling
Grouting
Verification
Immediate Actions
Alarm Plans
Standard Operating Procedures
Emergency Plans
DESIGN OF TUNNEL ADVANCE
Horizontal & Vertical Alignment - deeper tunnels have greater pressures, tight curves may require tapered rings
Geotechnical Interpretation - possible geological hazards, mixed face conditions, geological boundaries
Face Pressures - control of face pressure to avoid stress relaxation & overexcavation
Weights / Volumes - assessment of weight based on range of in-situ density, assess likely use of soil conditioning
Instrument Plan - types & distribution of instruments based on predicted settlements and location of buildings, frequency of reading
Settlement Contours & Settlement Limits - assessment of extent of predicted settlement, allows a check to be carried out during
construction
Required Consolidation Works - building protection worked to prevent any adverse effects due to settlement.
High Risk Areas, Structures & utilities- indicated on drawings to advise of additional care/reporting
Anticipated Anomalies & Actions - Loss of face pressure, additional grout, overexcavation
Probing - predicted geology, tates of penetration
TUNNEL MANAGEMENT PROCESS
DESIGN INPUT
DESIGN PROCESS
DESIGN OUTPUT
CONSTRUCTION INPUT
CONSTRUCTION PROCESS
CONSTRUCTION OUTPUT
Input 'field data'
&/or correction
factors into
design
TBM - GROUND INTERACTION
Compliance with settlement limits
Compliance with Face Pressure & Grout
requirements
Compliance with alignment
TBM Design
Segment Design
ALIGNMENT
VALIDATION -
Wriggle survey
ALIGNMENT
VERIFICATION - Track Work
Validation
CONFIRM
ALIGNMENT - Design
modifiaction may be
necessary, signalling,
route restrictions.