Numerical investigation of the convex effect on the behavior of crossing excavations  

作　　者：Min ZHANG Xing-hua WANG Guang-cheng YANG You WANG 

机构地区：[1]School of Civil Engineering, Central South University, Changsha 410075, China

出　　处：《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》2011年第10期747-757,共11页浙江大学学报（英文版）A辑（应用物理与工程）

基　　金：Project (No. 2007AA11Z134) supported by the National High-Tech R&D Program (863) of China

摘　　要：A 3D numerical model considering the soil-structure interaction is presented in this paper to examine the ground movement and internal force during the construction of Qingdao North Metro Station, China with a special focus on the convex effect of the crossing excavation. The influence of intersection angles and soil resilience characteristics on deformation behavior is discussed, and the suitability of two alternative constitutive models applied in excavation simulation is also considered. The analysis results show that a notable convex effect appears to be associated with the crossing excavation, and the intersection is the key area requiring special attention. The displacements at the comer decrease with increasing crossing angles. The axial loads of struts along the retaining pile wall are unequal, and the values near the cross section are generally larger than the average loads of the left-sided ones. The modified Cam-Clay （MCC） model, which is capable of describing the loading-unloading criterion and identifying the stiffness difference of strain hardening between loading and unloading, can yield a relatively high accuracy of estimation for the behavior of excavations in comparison to the Mohr-Coulomb （MC） model. Furthermore, slight soil deformation resilience after unloading can reduce the ground surface settlement and enhance the ground stability.A 3D numerical model considering the soil-structure interaction is presented in this paper to examine the ground movement and internal force during the construction of Qingdao North Metro Station, China with a special focus on the convex effect of the crossing excavation. The influence of intersection angles and soil resilience characteristics on deformation behavior is discussed, and the suitability of two alternative constitutive models applied in excavation simulation is also considered. The analysis results show that a notable convex effect appears to be associated with the crossing excavation, and the intersection is the key area requiring special attention. The displacements at the corner decrease with increasing crossing angles. The axial loads of struts along the retaining pile wall are unequal, and the values near the cross section are generally larger than the average loads of the left-sided ones. The modified Cam-Clay (MCC) model, which is capable of describing the loading-unloading criterion and identifying the stiffness difference of strain hardening between loading and unloading, can yield a relatively high accuracy of estimation for the behavior of excavations in comparison to the Mohr-Coulomb (MC) model. Furthermore, slight soil deformation resilience after unloading can reduce the ground surface settlement and enhance the ground stability.

关 键 词：Crossing excavation Convex effect Constitutive model Numerical simulation 

分 类 号：TU473[建筑科学—结构工程]