Tunnel Modelling in the Border Area Between Hard and Soft Rock

Poisel, Alexander (IGT Geotechnik und Tunnelbau ZT GmbH.) | Holzer, Robert (Geoconsult Wien ZT GmbH.)

OnePetro 

Abstract

An overburden height of about 1.5 times the tunnel diameter is known to be critical with regard to the stability of an underground excavation. The near-surface zone is usually affected by heavy weathering and represents the border area between hard and soft rock. Due to the variability of the rock mass parameters, a most accurate determination is required to allow for an adequate geotechnical design. For these geological conditions, it is vital to take a more "creative" approach to determine rock mass parameters rather than sticking too close to standard tests and existing classification systems. For numerical calculations and for the interpretation of monitoring results different strengths of the rock mass are taken into account as the ground behavior is sensitive when varying the input parameters.

1 Introduction

The geotechnical design of an underground excavation nowadays is a well-known procedure regulated by the Guideline for the Geotechnical Design of Underground Structures with Conventional Excavation (Austrian Society for Geomechanics 2010). Laboratory tests of rock to derive rock mass parameters are executed according to national standards. The latter also provide classification systems to describe rock and rock mass for engineering purposes. This practice is suitable for most cases, but some rock types require a different approach to describe them sufficiently for engineering purposes. Most of them lie within the border area between hard and soft rock. Regarding the geotechnical design, it also represents the transition zone between "stable" and "unstable" conditions. These kinds of rocks therefore demand special attention, but just in these cases the determination of rock mass parameters is extremely difficult.

We encountered the issue described above during the excavation of the Pummersdorf Tunnel, a 3.45 km NATM-Tunnel near the federal capital of St. Pölten. The prevailing overburden height of approximately 1.5 times the tunnel diameter (D) is critical with regard to the stability of an underground excavation (Vavrovsky 1987 and Poisel 2005). Rock failure in the crown up to the surface forming a chimney is an often monitored collapse phenomenon. This is a very critical failure mechanism, especially in horizontally layered rock. As it was observed during various tunnel excavations in the past, even little differences in the rock mass strength led to a collapse of the cavity (Vavrovsky 1993). These differences were often so little that they could not be determined on site by the geologist or the tunnel engineer.

The paper emphasizes the challenges of dealing with ground types described above for geologists and tunnel engineers.

Duplicate Docs Excel Report

Title
None found

Similar Docs  Excel Report  more

TitleSimilaritySource
Influence of the Primary Stress State on the Disc Cutter Penetration1.000OnePetro
Finite Element Simulations of Twin Shallow Tunnels1.000OnePetro
Earthquake Induced Rockfall Along Cut Slopes - A Case Study from Luhri, Himachal Pradesh, India1.000OnePetro
Characterization of Basalt for Stability Assessment of an Abandoned Underground Mine in Mendig, Germany1.000OnePetro
Effect of Time and Wear on the Basic Friction Angle of Rock Discontinuities1.000OnePetro
Physical and Numerical Simulations of Super-Critical Subsidence as Affected by Opening Geometries and Depths1.000OnePetro
Petrographic, Physical and Mechanical Features of Sedimentary Rocks of the South Catarinense Coalfield, Brazil1.000OnePetro
Numerical Methods for the Design of Support Systems in a Deep Metalliferous Mine in Turkey1.000OnePetro
Compressive Strength Tests of Cabled Rock Specimens as Pillar Analogues1.000OnePetro
Application of Artificial Neural Networks in Estimation of Uniaxial Compressive Strength using Schmidt Hammer Rebound Number Data under Specific Geological Conditions1.000OnePetro
3D Geometrical Modeling of Folded Layers: A Case Study from Lead and Zinc Mine of Anjire, Isfahan, Iran1.000OnePetro
Real Time Stress Change Estimation using Strain Measurements1.000OnePetro
Influence of Constitutive Model Choice on Simulated Stress Path and Yield Evolution in Deep Mine Pillar Analysis – Experience from the Creighton Mine, Sudbury, Canada1.000OnePetro
Rock Mechanics Investigations in Connection with the Introduction of a New Pillar System in a Deep Magnesite Mine1.000OnePetro
An investigation of Shaft Wall Stability in Low-Strength Rock Mass Conditions at the Ust-Jaiwa Freeze Shaft Project1.000OnePetro
Simulation of Mining Impact on Water Resources1.000OnePetro
On the Development of a Slope Instability Index for Open-Pit Mines using an Improved Systems Approach1.000OnePetro
Statistical Calculation of Mean Stress Tensor using both Euclidean and Riemannian Approaches1.000OnePetro
Stability Analysis of Internal Dragline Dump: Distinct Modeling1.000OnePetro
Stability Analysis of Blocky Rock Slope Excavation Bbased on Site Non-Contact Measurement and GeoSMA-3D Modelling1.000OnePetro
Rock Soil Usage to Provide Buildings and Structures Stability in Term of Deep-Frozen Soil1.000OnePetro
Rock mechanical analysis of the underground complex in Tapiola Center, Espoo, Finland1.000OnePetro
Probabilistic Numerical Models using Monte Carlo and Point Estimate Methods1.000OnePetro
Modelling of Rock Bolts using the Finite Element Method1.000OnePetro
Mapping Rock Surface Roughness with Photogrammetry1.000OnePetro
Investigations on Telescope Yielding Elements with Porous Filling1.000OnePetro
Effect of Carbon Dioxide Sequestration on the Mechanical Properties of Indian Coal1.000OnePetro
Dynamic Pressures in a Plunge Pool of a Dam1.000OnePetro
Tunnel Face Stability Investigation by Means of 3D Numerical Analysis and Hand Calculations1.000OnePetro
Suggestion for a Documentation of Unexpected Standstills in TBM-Tunnelling1.000OnePetro
Clump Models: An Improvement in the Rock Cutting Modelling by DEM?1.000OnePetro
Back Analysis of in Situ Stress at Shallow Depth using Discontinuum Numerical Modeling - A Case Study at the Odenplan Station in Stockholm, Sweden1.000OnePetro
Application of Numerical Modelling for Large-Scale Underground Excavation in Foliated Rock Mass1.000OnePetro
Applicability of Polyaxial Rock Peak Strength Criteria in Numerical Modeling1.000OnePetro
A Parametric Study for the Strength of Jointed Rock Mass1.000OnePetro
A Conceptual Approach to Modelling Rock Fracture using the Smoothed Particle Hydrodynamics and Cohesive Cracks1.000OnePetro
Seismic Induced Rock Landslides using Continuum-Based Models1.000OnePetro
The Impact of Reservoir Impounding on the Behavior of Deepseated Rock Slides1.000OnePetro
Yes, We Can! Challenges in Development of Geotechnical Failure Mechanisms with the Help of Numerical Modeling1.000OnePetro
Numerical Analyses of Deep Tunnels Driven Through Massive Faults1.000OnePetro
Upper Bound Limit Analysis of Uplift Failure in Pressurized Sealed Rock Tunnels1.000OnePetro
FEM Analysis of the Existing and New Linings for Diversion Tunnels No. 1 & 2 - Rogun Dam & HPP Project1.000OnePetro
Evaluating the Influence of Block Size in Cable Bolt Performance1.000OnePetro
Rock Mass Classification and Geotechnical Model for the Foundation of a RCC Gravity Dam1.000OnePetro
Simulation Aided Engineering – A Multi-Parametric Rock Mass Simulation Workflow1.000OnePetro
Simulation of Naturally Fractured Hard Rock Preconditioning via Hydraulic Fracturing1.000OnePetro
Numerical Modelling for Rock Temperature Prediction in Deep Tunneling - Methodology and Verification1.000OnePetro
Numerical Study on Slope Stability in Consideration of the Influence of Weathering by Two-Phase Flow Analysis1.000OnePetro
Numerical Simulation of Deep-Hole Resistivity Anomaly under Crustal Stress1.000OnePetro
Observations for the Long-Term Behaviour of Rocks Based on Laboratory Testing1.000OnePetro
Sustainable Lining in Incompetent Rock Mass Using the Example of Konrad Mine1.000OnePetro
Maintenance Experiences from Underground Facilities in Swedish Crystalline Rock1.000OnePetro
Sustainability of Hydro Structures in Erodible Rock in Two Hydro Electric Projects, Arunachal Pradesh, India1.000OnePetro
Investigation of Long-Term Behaviour of Support Elements in Tunnelling1.000OnePetro
Long Time Monitoring and Refurbishment of the Tie-backs of Untersberg Cable Car Pillar 11.000OnePetro
Long-term Deformation of Mountain Tunnel Lining and Ground Under Swelling Rock Condition1.000OnePetro
Investigation of Some Mechanical Properties of Rocks Under the Effect of Different Body Temperatures1.000OnePetro
Lifetime of Polyethylene Geomembranes for Water Proofing of Tunnels From the Perspective of Polymer Engineering1.000OnePetro
Slope Protection Systems for EBA and ÖBB - New Standards of Performance, Sustainability and Handling - German and Austrian Railways Criteria and Approval1.000OnePetro
Understanding Extremely Varying Stress Conditions in the Ground1.000OnePetro
Tunnel Excavation in Multiple Fractured Mudstone1.000OnePetro
Rosenstein-Tunnel Stuttgart: A New Road Tunnel Project under Challenging Urban Conditions1.000OnePetro
Karavanke Tunnels in Permo-Carboniferous Rock1.000OnePetro
Valhalla - Innovative Pumped Hydro Storage Facilities in Chile – Challenges From a Rock Mechanical Point of View1.000OnePetro
Tunneling Under Challenging Conditions – General Renovation, Escape and Safety Passageways via the Supply Air Duct at the “Arlberg Road Tunnel"1.000OnePetro
Challenges of Tunneling in Adverse Geology1.000OnePetro
Lessons Learned From the Heading of the Reconnaissance Tunnel for the Kramer Tunnel, Germany1.000OnePetro
On the Non-Uniformity of Squeezing Deformations in the Ceneri Base Tunnel1.000OnePetro
Re-excavation Model of the Collapsed Tunnel Section for the Metro Station Type 2 Tunnel in İzmir-Turkey1.000OnePetro
Tunneling Challenges in Large Caverns Under Densely-Built Urban Areas – Case: Helsinki City Rail Loop1.000OnePetro
Tunneling in Difficult Ground Conditions using Different Tunnel Boring Methods1.000OnePetro
Integrated Assessment of Cliff Rockfall Hazards by Means of Rock Structure Modelling Applied to TLS data: New Developments1.000OnePetro
Influence of Geological and Meteorological Factors on the Frequency of Rockfalls1.000OnePetro
An Empirical Approach to Rockfall Fragmentation1.000OnePetro
Construction in a Geotechnically Challenging Slope ? Design, Safety Management and Monitoring1.000OnePetro
Data Processing for Long-Term Monitoring of an Underground Radioactive Waste Repository1.000OnePetro
Long-Term Monitoring Experience at the Mont Terri Rock Laboratory, St-Ursanne, Switzerland1.000OnePetro
Monitoring the Ground in Order to Optimize Support: Ground Support Elements Equipped with Optical Frequency Domain Reflectometry Technology1.000OnePetro
Monitoring and Safety Management of Tunnels in the Vienna Metro Network1.000OnePetro
Monitoring and Integrated Data Management for Safe Urban Tunnelling1.000OnePetro
TBM Tunnelling in Tectonical Faults – Design Conclusions Drawn from the Observed System Behavior1.000OnePetro
Applying SWE Standards in Geo-Monitoring1.000OnePetro
Monitoring and Geotechnical Safety Management at a Large OeBB Railway Tunnel Project in Vienna in Soft Ground and Low Overburden1.000OnePetro
Slope Movement Monitoring with Optical Fiber Technology1.000OnePetro
Scaling Effects on Elastic Properties of Jointed Rock Mass1.000OnePetro
Effects of Structural Contact Stiffness and Strength on Progressive Failure of Healed Structure1.000OnePetro
Laboratory Tests on Dutch Limestone (Mergel)1.000OnePetro
Comparison of Constant Normal Load (CNL) and Constant Normal Stiffness (CNS) Direct Shear Tests1.000OnePetro
Composite Elasticity of Copenhagen Limestone1.000OnePetro
Geotechnical Characterization of the Antalya Karstic Rock Masses1.000OnePetro
Obtaining Foundation Rock Mass Properties of the Surqawshan Earth Dam using UDEC1.000OnePetro
Mechanical Characterization of Tectonic Faults: Closing the Gap1.000OnePetro
A New Model of Strain Energies to Solve the Drawbacks of the Classical Limit Equilibrium Models of Forces for Rock Joints1.000OnePetro
Analysis of Stress-Strain Anisotropy of Soft Rock (by Example of Claystones)1.000OnePetro
Analyzing Schmidt Hammer in Evaluating Compressive Strength of Rock Mass1.000OnePetro
Application of Artificial Neural Networks in Estimation of Uniaxial Compressive Strength using Indirect Tensile Strength Data of Limestone Rocks1.000OnePetro
Comparison of Elastic Properties of Fractured Triassic Carbonate Rocks on a Base of Geophysical Research1.000OnePetro
Comparison of Mechanical Strength Prediction with Schmidt Hammer Rebound Value and Rebound Coefficient1.000OnePetro
Determining Strength and Fracture Toughness of Rock from Scratch Tests1.000OnePetro