Study on Surface Settlement Law of Shield Construction in Mudstone Stratum

Abstract

In order to explore the influence of groundwater on the surface settlement law of shield construction under mudstone with different weathering degrees, this paper studies the influence of buried depth on surface settlement under different weathered mudstone, and the influence law of groundwater in stratum and different depths of water level on settlement of shield construction using a three-dimensional(3D) numerical model establish by finite element software based on the engineering background of Chengdu Metro Line 18. The results show that: (1) With the increase of buried depth, the range of lateral settlement trough on the surface gradually increases, but the maximum settlement gradually decreases. By analyzing the buried depth and the maximum surface settlement, it is found that the buried depth ratio has a logarithmic relationship with the corresponding maximum surface settlement. (2) The construction settlement increases obviously when there is groundwater in the stratum compared with when there is no groundwater. (3) The depth of water level above the vault and the maximum settlement caused by shield construction basically conform to the linear law. For every 1m increase in the depth of water level above the vault, the maximum settlement value can increase by about 0.43 mm. Compared with the field monitoring data, the calculation results are basically consistent, which shows the reliability of the calculation. This paper aims to provide experience for similar projects.