基坑工程三维数值分析中本构模型的应用探讨Discussionon.PDFVIP

基坑工程三维数值分析中本构模型的应用探讨 谢晓锋 （广东省建筑科学研究院，广东广州 510500 ） 摘要：随着基坑工程的日益复杂，数值分析方法已成为分析基坑开挖问题的重要手段。三维数值分析在基坑工程 中应用的关键在于如何合理地选择土体本构模型和参数。本文在前人研究工作的基础上，分别采用最常用的两种 本构模型—Mohr-Coulomb模型和Modified Cam-clay模型，对某基坑的真实施工过程进行三维数值分析，通过研究 基坑底部和基坑周边土体变形情况分析两种本构模型在基坑工程三维数值分析中的适用性和优缺点。研究结果表 明，Mohr-Coulomb模型由于卸载和加载模量相同，应用于基坑开挖时会导致不合理的回弹，只适用于初步分析； 而Modified Cam-clay模型由于刚度依赖于应力水平和应力路径，计算结果更趋合理，适用于较精确的分析。本文 的研究成果可为复杂基坑的三维数值分析提供借鉴和参考。 Discussion on applicability of constitutive models for 3D numerical analysis of foundation pit construction X. Xie (Guangdong Provincial Academy of Building Research, Guangdong Province, Guangzhou City 510500) Abstract: As the development of foundation pit engineering is becoming more and more challenging, the numerical analysis method has become an important means of the analysis of foundation pit construction. One of the key points for 3D numerical modeling practice is the proper selection of existing constitutive models for soil as well as the reasonable estimate of properties for parameters associated with the model. After reviewing previous research, a particular case of foundation pit has been selected for the study of further investigation of the two most commonly-used constitutive models, i.e., the Mohr-Coulomb model and the Modified Cambridge model. The advantage of one model over another is judged in terms of the agreement of the model-referred deformation with the actual one collected in the field on both the foundation and the sidewalls of the pit. Through this study it has been found that the Mohr-Coulomb model seems to be applicable to preliminary analysis due to the assumption of equal modules for both loading and unloading. In this case, an un