Ground loss model for analyzing shield tunneling-induced surface settlement along curve sections

In order to relieve the increasing ground traffic pressure in the process of urbanization in China, it is inevitable to build more metro lines. However, the stratum movement caused by tunneling affects the safety of adjacent underground structures and aboveground buildings. Therefore, how to evaluate and control the stratum movement is a prominent problem. In this paper, based on the engineering project of an interval tunnel between Shizishan Station and Chuanshi Station in Chengdu Metro Line 7, China, the action mechanism of stratum movement induced by shield tunneling is analyzed, and the effect factors are divided into two categories: ground loss factors and mechanical factors. Combining the advantages of Loganathan method and mirror source-sink method, a new solution of three-dimensional displacement induced by ground loss is proposed. Based on the elastic half-space Mindlin model, the displacement at any point induced by four mechanical effect factors is deduced. Finally, the total displacement is verified by field monitoring data and quantitative analyzed in various parts.

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

Applied Sciences ◽

10.3390/app9071399 ◽

2019 ◽

Vol 9 (7) ◽

pp. 1399 ◽

Cited By ~ 7

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.

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A method of estimating surface settlement above tunnels constructed in soft ground

Canadian Geotechnical Journal ◽

10.1139/t83-002 ◽

1983 ◽

Vol 20 (1) ◽

pp. 11-22 ◽

Cited By ~ 82

Author(s):

R. K. Rowe ◽

K. Y. Lo ◽

G. J. Kack

Keyword(s):

Elastic Modulus ◽

Elastic Anisotropy ◽

Soft Soil ◽

Surface Settlement ◽

Initial Stresses ◽

Rigid Base ◽

Factors Affecting ◽

Plastic Failure ◽

Ground Loss ◽

The Difference

A technique suitable for the analysis of lined tunnels constructed in soft soil is described. This technique permits consideration of the soil-lining interaction, lining weight, and plastic failure within the soil. Particular attention is given to the simulation of loss of ground including the annular void created by the difference between the tunnelling machine and lining diameters. The analysis is used in a parametric study to identify potentially significant factors affecting the prediction of surface settlement due to tunnel construction. Consideration is given to the effects of elastic modulus; the distance between the tunnel and the underlying rigid base stratum; plastic failure; initial stresses; ground loss (including the annular void); and the injection of clay grout into the tailpiece void. The results of this analysis indicate that elastic anisotropy, ground loss, and clay grout injection are all important factors that are not usually considered in analyses. In particular, a parameter called the gap is defined in the paper and is used in an attempt to incorporate practical tunnelling experience into the calculation of surface settlement. Furthermore, it is shown that in predicting surface settlements underestimation of the true elastic modulus below the tunnel may decrease the predicted surface settlement and lead to overestimation of the invert heave. Underestimation of the modulus above the tunnel may also decrease the predicted surface settlement for situations where there is limited ground loss and extensive plastic failure.

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Prediction of maximum surface settlement caused by earth pressure balance (EPB) shield tunneling with ANN methods

SOILS AND FOUNDATIONS ◽

10.1016/j.sandf.2018.11.005 ◽

2019 ◽

Vol 59 (2) ◽

pp. 284-295 ◽

Cited By ~ 31

Author(s):

Ren-Peng Chen ◽

Pin Zhang ◽

Xin Kang ◽

Zhi-Quan Zhong ◽

Yuan Liu ◽

...

Keyword(s):

Earth Pressure ◽

Surface Settlement ◽

Pressure Balance ◽

Shield Tunneling ◽

Maximum Surface ◽

Earth Pressure Balance ◽

Maximum Surface Settlement ◽

Epb Shield

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Numerical Analysis of Pipelines Settlement Induced by Tunneling

Advances in Civil Engineering ◽

10.1155/2019/4761904 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

KunYong Zhang ◽

Jose Luis Chavez Torres ◽

ZhenJun Zang

Keyword(s):

Elastic Modulus ◽

Three Dimensional ◽

Surface Settlement ◽

Soil Parameters ◽

Practical Case ◽

Shield Tunneling ◽

Dimensional Finite Element ◽

Maximum Surface Settlement ◽

Three Dimensional Finite Element ◽

Grey Relational

Three-dimensional finite element method analysis on the tunnel-soil-underground pipeline was carried out based on the ABAQUS program. PSI element was applied to simulate the interaction between the pipelines and soil. Parameters such as an elastic modulus of soil, stress release rate, at-rest lateral pressure coefficients, an elastic modulus of pipelines, and buried depths of tunnels were analyzed. The effects of tunnel excavation on the displacement of existing pipelines were investigated, and the settlement relationships were obtained. The relationship between each parameter and surface settlement was determined by the grey relational analysis method to analyze each parameter’s sensitivity to the settlement of the pipeline, which can provide a reference for emphasis and methods of shield tunneling support. Finally, a formula of the settlement relationship between the maximum surface settlement and pipelines deformation was proposed for different pipe-soil relative stiffness. The formula was applied in the practical case. Compared with the field monitoring results and FEM computer results, it has been found that the proposed normalized formula is consistent with the measured results and numerical simulation of the pipeline settlement.

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