土体硬化模型参数试验研究及其在南昌地区基坑工程的应用

刘伟煌 朱怀龙 贺斯进 言建标 徐长节

摘 要：基坑开挖数值分析的关键在于土体本构的选择和计算参数的合理选取，硬化模型（HS模型）是应用较为广泛的模型之一。通过采用GDS空心扭剪试验仪（SS-HCA）和常规固结仪完成大量室内试验，获取了南昌地区软土层的硬化模型参数，对各层土参数中模量之间的比例关系进行探讨，并将试验得到的结果与相关文献的结果进行比较和总结。运用PLAXIS有限元数值计算软件，对南昌某地下室深基坑工程进行数值模拟，土体本构模型采用程序内置的HS模型。结果表明，围护桩深层水平位移的实测数据与数值计算结果基本吻合，表明获取的HS模型参数及方法适用于南昌地区基坑开挖的数值分析。

关键词：土体硬化模型;基坑工程;空心扭剪试验仪;室内试验

中图分类号：TU411.3;TU753.1 文献标志码：A 文章编号：2096-6717（2021）06-0038-10

Abstract： The significance of numerical analysis of foundation pit excavation lies in the selection of soil constitution and reasonable input parameters.The hardening model（HS model） is one of the soil constitutive models that are widely used.In this paper， the GDS Hollow Torsion Shear Tester （SS-HCA） and consolidation apparatus were used to complete a series of laboratory tests.The parameters of the hardening model of the soft soil layer in Nanchang were obtained through the tests. The proportional relationship between the modulus of each layer of soil parameters has been discussed.The experimental results were compared with the result from literatures. Then， the PLAXIS finite element software was used to conduct numerical simulation of a certain basement deep foundation pit project in Nanchang. The soil constitutive model adopted the programmed HS model. The results show that the calculated value of the deep horizontal displacement of the retaining pile is basically consistent with the measured value. The HS model and the determination method for parameters have been proved to be applicable in numerical analysis of foundation pit excavation engineering in Nanchang area.

Keywords：hardening soil model; foundation pit engineering; hollow torsional shear tester; laboratory test

隨着经济的发展，南昌地区的基坑数量也随之增多，基坑规模也越来越大，加之城市用地日益紧张，基坑周边常遇到地下管线、地铁隧道、高架桥等建筑。在这种复杂情况下，基坑工程除满足自身的变形要求外，还需要保证其周边环境的安全性，这对基坑工程的设计提出了更高的要求。目前，分析基坑开挖对周边环境影响的方法有解析法和相关规范法[1-2]。但考虑问题的复杂性，传统的解析法和规范法难以真实地反映基坑开挖期间对周边环境的影响。随着有限元和计算机的发展，数值分析法[3-5]越来越成为深基坑变形分析中常用且有效的方法，而数值分析法的关键问题之一在于采用合适的土体本构模型和选取合理的计算参数[6]。……