Ground Deformations Resulting from Shield Tunnelling in London Clay

1974 ◽  
Vol 11 (3) ◽  
pp. 380-395 ◽  
Author(s):  
P. B. Attewell ◽  
I. W. Farmer
Keyword(s):  
Interaction Effect ◽  
Surface Settlement ◽  
Ground Movements ◽  
Yield Rate ◽  
Ground Deformations ◽  
Normal Probability ◽  
Shield Tunnelling ◽  
London Clay ◽  
Maximum Surface Settlement ◽  
Final Settlement

The paper describes the results of a field measurement program aimed at determining the ground movements created by the hand excavation of a 4.146 m diameter shield-driven tunnel at a depth of 29.3 m in stiff, fissured, heavily overconsolidated London clay. Approximately half of the recorded maximum surface settlement of 6.1 mm is both measured and calculated to have taken place during passage of the shield, the remainder being attributed to post-shield deformations. Calculations are based on a field and laboratory-determined average radial yield rate for the clay at the tunnel of 0.0055 mm/min. It is concluded that a normal probability surface settlement profile is developed over the shield and tail.Post-shield inward decompressions (K0 ≈ 1.65) and possible recompression as a clay–grout interaction effect could then be responsible for a slight reconsolidation of the clay at soffit and for distortion of the final settlement profile out of concordance with an error curve.

scholarly journals Quantitative Evaluation of Ground Movements Caused by Grouting during Shield Tunnelling in Clay

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Zhi-Feng Wang ◽  
Wen-Chieh Cheng ◽  
Ya-Qiong Wang
Keyword(s):  
Cylindrical Cavity ◽  
Radial Stress ◽  
Soft Soil ◽  
Tunnel Construction ◽  
Reliable Measure ◽  
Simple Method ◽  
Ground Movements ◽  
Tunnel Boring ◽  
Shield Tunnelling ◽  
London Clay

Grouting has been deemed as one of the most effective measures for mitigation of ground movements during tunnel construction in soft soil. Notwithstanding that, a reliable measure to quantitatively evaluate the grouting-induced ground movements during shield tunnelling in soft soil has not yet been developed. This paper presents a simple method capable of quantitatively estimating the ground movements associated with grouting for tunnel-boring operations where the grouting parameters and soil properties are taken into consideration. The grouting process is simplified as the expansion of a cylindrical cavity with a uniform radial stress applied at soil-grout interface in a half plane, and the analytical solution proposed by Verruijt is introduced for determining the ground movements by the expansion of the cylindrical cavity. The proposed method is verified with a case history undertaken in London Clay. The results obtained suggest that this procedure would be helpful in managing the grouting parameters adopted in upcoming soft ground tunnelling project and mitigating the environmental impacts on nearby properties.

Chapter 17 Mining-induced fault reactivation in the UK

2020 ◽  
Vol 29 (1) ◽  
pp. 425-432 ◽  
Author(s):  
Laurance Donnelly
Keyword(s):  
Coal Mining ◽  
Ground Deformation ◽  
Ground Surface ◽  
Surface Mining ◽  
Fault Reactivation ◽  
Mining Subsidence ◽  
Ground Movements ◽  
Ground Deformations ◽  
Coal Mining Subsidence ◽  
The Uk

AbstractFaults are susceptible to reactivation during coal mining subsidence. The effects may be the generation of a scarp along the ground surface that may or may not be accompanied by associated ground deformation including fissuring or compression. Reactivated faults vary considerably in their occurrence, height, length and geometry. Some reactivated faults may not be recognizable along the ground surface, known only to those who have measured the ground movements or who are familiar with the associated subtle ground deformations. In comparison, other reactivated faults generate scarps up to several metres high and many kilometres long, often accompanied by widespread fissuring of the ground surface. Mining subsidence-induced reactivated faults have caused damage to roads, structures and land. The objective of this chapter is to provide a general overview of the occurrence and characteristics of fault reactivation in the UK.

Surface settlement during shield tunnelling at CH218 in Taipei

1998 ◽  
Vol 35 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Chang-Yu Ou ◽  
Richard N Hwang ◽  
Wei-Jung Lai
Keyword(s):  
Ground Surface ◽  
Earth Pressure ◽  
Surface Settlement ◽  
Pressure Balance ◽  
Transit System ◽  
Ground Surface Settlement ◽  
Earth Pressure Balance Shield ◽  
Shield Tunnelling ◽  
Earth Pressure Balance ◽  
Twin Tunnels

This paper presents the surface settlement performance induced by the foamed type of earth pressure balance shield in contract CH218 of the Hsintien Line of the Taipei Rapid Transit System. The surface settlement characteristics caused by the single tunnel and by twin tunnels with reference to two sections spaced at 87 m are studied. Field observations indicate that the surface settlement trough due to the single tunnel can be represented by the normal distribution. The distance of the inflection point to the tunnel center and maximum surface settlement value are consistent with those found in the literature. The characteristics of the surface settlement trough are related to the type of the soil, particularly where the crown of the tunnel is located in a layered soil deposit. The ground surface settlement induced by twin tunnels was found to be larger than estimated using the principle of superposition.Key words: shield tunnelling, surface settlement, field observation.

Predicted versus measured soil movements induced by shield tunnelling in the Madrid Metro extension

2005 ◽  
Vol 42 (4) ◽  
pp. 1160-1172 ◽  
Author(s):  
Manuel Melis Maynar ◽  
Luis Medina Rodriguez
Keyword(s):  
Numerical Model ◽  
Numerical Modelling ◽  
Earth Pressure ◽  
Pressure Balance ◽  
Ground Movements ◽  
The Earth ◽  
Shield Tunnelling ◽  
Earth Pressure Balance ◽  
Numerical Modelling And Analysis ◽  
Soil Movements

A detailed study on the available methods of predicting ground movements due to tunnelling works was carried out during the construction of the Madrid Metro extensions in 1995–1999 and 1999–2003. A total of 100 km were built and commissioned during this period. A numerical model was developed to simulate the earth pressure balance (EPB) excavation procedure and to complement some of the deficiencies found in previous analytical or empirical subsidence estimation procedures. Before the beginning of the works, a total of six different methods were used to estimate ground movements generated by the tunnelling works at some monitored sections placed in all five cities linked by the 1999–2003 extension, and the estimations were published in an earlier paper in this journal. Once all tunnelling works were finished and actual measurements carried out, a number of comparisons between predictions and measurements were made and are included in this paper. Conclusions about the applicability and accuracy of the methods are established with the aim of helping researchers and engineers in their future projects.Key words: ground movements, monitoring, numerical modelling and analysis, settlement, tunnels.

scholarly journals Performance of Slurry Shield Tunnelling in Mixed Strata Based on Field Measurement and Numerical Simulation

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Jian Cui ◽  
Wang-Hao Xu ◽  
Yong Fang ◽  
Li-Ming Tao ◽  
Chuan He
Keyword(s):  
Measurement Data ◽  
Tunnel Boring Machine ◽  
3D Models ◽  
Surface Settlement ◽  
Engineering Practice ◽  
Silty Clay ◽  
Pressure Balance ◽  
Shield Tunnelling ◽  
The Difference ◽  
Slurry Shield

There are severe challenges for slurry pressure balance tunnel boring machine (TBM) tunnelling in sandy cobble soil of Beijing, Chengdu, and Lanzhou in China. And the problems caused by tunnelling from silty clay to sandy cobble stratum are more serious. With the change of stratum, the key parameters and surface settlement will change correspondingly. Controlling the key parameters and predicting the surface settlement accurately and efficiently is important for hazard mitigation and risk management. In this study, based on the Tsinghuayuan Tunnel project in Beijing, the key parameters and surface settlement while tunnelling from silty clay to sandy cobble stratum are studied. Firstly, the difference of key parameters while tunnelling in two different strata is analyzed. The analysis shows that immediate responses to changes in the stratum are recommended in order to ensure construction efficiency. Then, a refined 3D finite difference model is developed to simulate the slurry TBM tunnelling in different strata. For refined simulation, three key parameters obtained from measurement data were applied to the 3D models, and the simulation results were compared with the field data. Results show that the refined model has good performance in terms of the accuracy and efficiency. This study provides a good engineering practice reference for slurry TBM tunnelling in mixed strata.

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