砂卵石地层基坑开挖土体本构模型辨识研究

Identification of Constitutive Model for Sandy Cobble Ground Foundation Pits Excavation

随着基坑工程分布的广泛性,施工过程中会遇到各种复杂的地质条件,其中砂卵石就是一种广泛分布的特殊地层。为了解砂卵石地层中基坑开挖的变形特征,探究砂卵石土体的本构模型,该文首先详细介绍了Harding-Soil模型的理论基础,然后采用均匀设计(UD)与有限元(FEM)计算相结合的方法对本构模型的未知参数进行辨识,均匀设计可以减少计算量并保证试验方案的科学性、准确性,最后结合长沙地区某在建砂卵石地铁深基坑工程进行实例验证Harding-Soil模型描述砂卵石地层开挖行为的适用性。有限元计算结果表明Harding-Soil模型能较准确的描述砂卵石基坑的变形特征,且利用均匀设计(UD)与有限元(FEM)计算相结合的方法对本构模型的未知参数进行辨识是可行的。

With the extensive distribution of foundation pits, a variety of complex geological conditions will be met during the course of construction, the sandy cobble ground is one of the widely distributed special stratums. In order to know the deformation characteristics of sandy cobble ground foundation pits excavation, and explore the constitutive model of sandy cobble ground, first of all, the theoretical foundation of the Harding-Soil model is thoroughly introduced in this paper, and then to take advantage of the method of combining uniform design and FEM computation to identify the unknown parameters of the constitutive model, the uniform design can effectively reduce the computation procedures and ensure that the test design scheme is scientific and exact. The FEM computation is based on finite element program which can simulate the seepage of groundwater. Finally, a deep sandy cobble subway foundation pit under construction in Changsha verifies the applicability of the Harding-Soil model in describing the sandy cobble ground foundation pits excavation behavior. The FEM computation outcome shows that the Harding-Soil model successfully described the deformation characteristics of sandy cobble ground foundation pits, and the method of combining uniform design and FEM computation to identify the unknown parameters of the constitutive model is feasible.