Reliability Analysis of Ground Surface Settlement Given Multivariate Spatial Random Field in Shield Tunneling

2018 ◽  
pp. 181-189
Author(s):  
Changhong Wang
Keyword(s):  
Random Field ◽  
Reliability Analysis ◽  
Ground Surface ◽  
Surface Settlement ◽  
Shield Tunneling ◽  
Ground Surface Settlement ◽  
Spatial Random Field

scholarly journals Analysis of the Additional Stress and Ground Settlement Induced by the Construction of Double-O-Tube Shield Tunnels in Sandy Soils

2019 ◽  
Vol 9 (7) ◽  
pp. 1399 ◽  
Author(s):  
Wen Zhao ◽  
Peng-jiao Jia ◽  
Lin Zhu ◽  
Cheng Cheng ◽  
Jianyong Han ◽  
...  
Keyword(s):  
Ground Surface ◽  
Field Measurements ◽  
Surface Settlement ◽  
Additional Stress ◽  
Underground Construction ◽  
Shield Tunneling ◽  
Engineering Project ◽  
Ground Surface Settlement ◽  
Potential Damage ◽  
Lateral Friction

Double-O-tube shield tunneling has attracted increasing attention because it offers cost-efficiency in underground construction. Prediction of ground surface settlement and the variety of additional stresses induced by shield construction is crucial to underground construction in metropolises since excessive settlement could trigger potential damage to the surrounding environment. The additional stresses induced by the propulsion of double-O-tube shields are calculated by means of the Mindlin’s equations of elasticity. The characteristics of additional stresses are analyzed with compound Gauss-Legendre integral arithmetic, and the frontal additional thrust, the lateral friction, and the ground loss are taken into account. Subsequently, based on field measurements, the maximum settlement coefficient and width of the settlement trough coefficient of the typical Peck formula are modified. The predictive curve of the Peck formula is closer to the engineering measured data than that of the typical formula. The cut-off functions of ground surface settlement caused by double-O-tube tunnel shield construction are proposed and can predict the shape of ground surface settlement, such as single peak or double peak. The correctness of the proposed functions is verified based on an engineering project.

scholarly journals Slurry shield tunneling in soft ground. Comparison between field data and 3D numerical simulation

2019 ◽  
Vol 41 (3) ◽  
pp. 115-128
Author(s):  
Mohammed Beghoul ◽  
Rafik Demagh
Keyword(s):  
Urban Areas ◽  
Ground Surface ◽  
Injection Pressure ◽  
Tunnel Boring Machine ◽  
Surface Settlement ◽  
Ground Movement ◽  
Shield Tunnel ◽  
Shield Tunneling ◽  
Ground Movements ◽  
Ground Surface Settlement

Abstract In urban areas, the control of ground surface settlement is an important issue during shield tunnel-boring machine (TBM) tunneling. These ground movements are affected by many machine control parameters. In this article, a finite difference (FD) model is developed using Itasca FLAC-3D to numerically simulate the whole process of shield TBM tunneling. The model simulates important components of the mechanized excavation process including slurry pressure on the excavation face, shield conicity, installation of segmental lining, grout injection in the annular void, and grout consolidation. The analysis results from the proposed method are compared and discussed in terms of ground movements (both vertical and horizontal) with field measurements data. The results reveal that the proposed 3D simulation is sufficient and can reasonably reproduce all the operations achieved by the TBM. In fact, the results show that the TBM parameters can be controlled to have acceptable levels of surface settlement. In particular, it seems that moderate face pressure can reduce ground movement significantly and, most importantly, can prevent the occurrence of face-expected instability when the shield crosses very weak soil layers. The shield conicity has also an important effect on ground surface settlement, which can be partly compensated by the grout pressure during tail grouting. Finally, the injection pressure at the rear of the shield significantly reduces the vertical displacements at the crown of the tunnel and, therefore, reduces the settlement at the ground surface.

scholarly journals Spatial Variability of Grouting Layer of Shield Tunnel and Its Effect on Ground Settlement

2020 ◽  
Vol 10 (14) ◽  
pp. 5002
Author(s):  
Zhongzheng Wang ◽  
Dalong Jin ◽  
Chenghua Shi
Keyword(s):  
Spatial Variability ◽  
Negative Impact ◽  
Ground Surface ◽  
Surface Settlement ◽  
Shield Tunnel ◽  
Ground Settlement ◽  
Shield Tunneling ◽  
Spatial Characteristics ◽  
Ground Surface Settlement ◽  
Prediction Approach

This study aims to investigate the effect of the spatial variability of grouting-layer thickness on ground-surface settlement caused by shield tunneling and to provide a rational prediction method. The spatial characteristics of grouting layers were obtained based on statistical analysis. The random finite element method was used to study the effect of spatial variability of different parameters on ground-surface settlement. Simulation results indicate that the spatial variability of the grouting layer has a negative impact on ground settlement. The surface settlement will be underestimated without considering the spatial characteristics of the grouting layer. Thus, a reliable prediction approach of the maximum ground settlement was proposed to control the construction quality.

Prediction on Ground Surface Settlement Caused by Subway Shield Construction in Xi'an

2013 ◽  
Vol 353-356 ◽  
pp. 1534-1538
Author(s):  
Rong Di Liu ◽  
Jian Guo Zheng ◽  
Kai Zhang ◽  
Zhi Yuan Li
Keyword(s):  
Ground Surface ◽  
Surface Settlement ◽  
Characteristic Parameters ◽  
Prediction Formula ◽  
Shield Tunneling ◽  
Ground Surface Settlement ◽  
Subway Construction ◽  
Actual Settlement ◽  
Relevant Calculation

In order to study the ground surface settlement induced by shield tunneling, on the background of Xi'an metro line 2, this paper made use of the measured ground surface settlement to conduct characteristic parameters fitting of the settlement trough by Peck formula and the modified stiffness approach, proposed the initial suggestive value of the relevant calculation parameters, predicted the ground surface settlement by the formula with the determined parameters and compared the settlement with the actual settlement observation. The results show that the determination of the parameters is basicly right, the revised formula can be used to forecast ground surface settlement of Xi'an subway construction and finally a modified prediction formula is given.

scholarly journals Effects of Different Construction Sequences on Ground Surface Settlement and Displacement of Single Long Pile due to Twin Paralleled Shield Tunneling

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Kan Huang ◽  
Yiwei Sun ◽  
Xianqiang Huang ◽  
Yujian Li ◽  
Meng Jiang ◽  
...  
Keyword(s):  
Urban Areas ◽  
Pile Foundation ◽  
Ground Surface ◽  
Horizontal Displacement ◽  
Element Model ◽  
Surface Settlement ◽  
Pile Foundations ◽  
Shield Tunneling ◽  
Construction Sequence ◽  
Ground Surface Settlement

Shield tunneling activities inevitably pass through pile foundations at close distance in densely urban areas. Various studies have investigated the interaction between newly constructed tunnels and existing pile foundations. However, the influence of different construction sequences of twin paralleled shield tunneling on single long pile is seldom considered. A case was found in the project of Changsha Metro Line 5, where the twin paralleled tunnels were constructed near the Wanjiali Viaduct piles. A three-dimensional finite element model was established to analyze the pier settlement, ground surface settlement trough, and the vertical and horizontal displacement of pile under different construction sequences in layered soil. The results show that the adjacent pile and surrounding environment are affected substantially with the change of construction sequence of twin paralleled tunnels. The construction sequence of condition (b), in which the tunnel closer to the pile foundation is first constructed and then the tunnel farther away from the pile foundation is second constructed, can reduce the settlement of pier by 13.1%, the maximum surface settlement by 7.0%, the maximum vertical displacement of pile foundation by 7.9%, and the maximum horizontal displacement by 6.9%. The present findings can provide reference for similar projects.

Sign in / Sign up

Export Citation Format

Share Document