花岗岩残积土硬化土模型参数反演及工程应用

近年来在花岗岩残积土层运营地铁线路周边进行的工程建设逐渐增多，对盾构隧道安全的影响不容忽视。有限元法是评估临近施工对隧道影响的有效手段，但其可靠程度取决于土体本构模型和参数的合理选取。首先对花岗岩残积土硬化土模型参数取值现状进行评述，随后提出一种基于自钻式旁压试验的残积土硬化土模型参数反演方法，最后将反演的参数应用于深圳典型基坑上跨隧道施工的工程案例中进行验证分析，确定较为合理的残积土硬化土模型参数取值范围。研究结果表明，花岗岩残积土硬化土模型的强度参数可根据室内试验确定，刚度参数 、 和 是反演的关键参数，适用于工程实际的 : : 可取为1:1:3～1:1:5，根据比例不同， 取值范围在36～43 MPa之间。

Parameter back-analysis of hardening soil model for granite residual soil and its engineering applications

In recent years, construction works near the operating metro tunnel in granite residual soil have been gradually increasing, and the impact of these construction works on the safety of shield tunnel should not be ignored. Finite element method is an effective method to evaluate the influence of adjacent construction on shield tunnel, but its reliability highly depends on the reasonable selection of soil constitutive model and parameters. In this paper, the current situation of parameter selection of hardening soil model for granite residual soil is firstly reviewed. Then a back-analysis method for determining the parameters of granite residual soil based on the self-boring pressure meter test (SBPT) is proposed. Finally, the obtained back-analysis parameters are applied to the engineering case of foundation pit excavated overpass existing shield tunnel for method verification, and more reasonable values of parameters of hardening soil model for granite residual soil are determined. The results show that the strength parameters of hardening soil model for granite residual soil can be determined by laboratory tests, and the stiffness parameters of , and are the key parameters for the back-analysis. The ratio of : : from 1:1:3 to 1:1:5 is suitable for engineering practice, and the value of ranges from 36 MPa to 43 MPa according to different ratios.