Investigating the effectiveness of factors affecting lateral displacement and surface uplift during tunneling operation using slurry pipe jacking method

Authors

1 Faculty of Engineering, Tarbiat Modares University, Tehran

2 Assistant Professor, Department of Engineering, Tarbiat Modares University, Tehran

Abstract

In this article, considering the pipe jacking operations in soft soil and under groundwater as an engineering field, the ground deformation in different directions and also the uplift of the ground surface has been analyzed using numerical simulation. This study focused on the factors that mainly affect the ground displacement such as excavation space diameter, placement depth, slurry injection pressure, excavation face pressure, soil elastic modulus, friction angle and cohesion. The purpose of this study is to provide a theoretical basis for controlling and reducing deformation of the earth during pipe jacking operations. Numerical simulation was performed using Plaxis finite element numerical software and case study. Then the effect of each parameter on the pattern of ground deformation in three directions and also estimating the amount of uplift and their exact location were investigated. The relationship between each parameter and the lateral displacement of the ground was estimated and finally the effect of each of the different factors was measured using sensitivity analysis and the sensitivity index of each was determined. The results show that the diameter of the excavation space is the most sensitive and the slurry injection pressure is the least sensitive to other parameters in lateral displacement of the ground (u-y), so more accuracy in estimating them should be used in preliminary studies. The maximum uplift occurs about 8 m (2.4 D) in front of the excavation face and then gradually decreases. As the slurry injection pressure triples,

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