基于非线性有限单元法的岩体开挖稳定性分析方法研究

【作者】 张军涛；

【导师】 张立翔；

【作者基本信息】 昆明理工大学 ， 水工结构工程， 2006， 硕士

【摘要】 目前岩体稳定分析的理论和方法很多，常用计算方法有极限平衡法、有限元法、可靠度分析和模糊极值理论等。随着计算机技术、固体力学非线性理论与求解技术的不断发展，有限元分析方法在岩体稳定性分析中得到越来越广泛的应用。有限元法不但能够对岩体的稳定性进行定量的评价，而且能够考虑岩体的不连续性，岩体应力应变关系的非线性特性及力学性质方面的各向异性；能够计算岩体的弹性变形状态，也能够计算岩体的破坏状态，不但可以考虑岩体中的地应力或区域构造应力条件，也可以考虑一些特定条件的作用与影响。应用有限元法，滑动面上的法向力和切向力可直接从有限元应力分析成果中获得，这样就避免人为的假定，克服了极限平衡分析法的大部分缺陷。本论文简要回顾和评述了岩体稳定性的分析方法，介绍了目前一些常用的方法和一些新的研究成果；系统阐述了非线性有限元分析的基本原理，详细介绍了基于非线性有限元原理的岩质块体稳定性分析方法，并将此方法应用到某一水电站右冲砂底孔左岸开挖岩体的稳定性分析研究中。此右冲砂底孔左岸岩体局部区域被结构面所切割，完整性较差，有轻微的蚀变，岩体力学参数指标偏低，岩体开挖前后的稳定状况直接关系到工程的施工安全、施工进度和经费预算等。因此有必要对此岩体的稳定性进行综合评价。研究结果表明，基于非线性有限元原理的岩体稳定性分析方法能准确有效地对岩体的稳定性进行定性定量的综合分析，准确评价和预测岩体的稳定状况和变形发展趋势，为加固处理措施提供了可靠的依据和合理的建议，确保了开挖施工过程中工程及结构的安全，经济有效地保证了右冲砂底孔左岸岩体的稳定性。更多还原

【Abstract】 Currently, there are many kinds of the theories and methods of the slope stability analysis, the common calculation methods are the limit equilibrium theory, the finite element method, the reliability analysis and the fuzzy theory. With the development of computer technology, solid mechanics and the nonlinear theory, the finite element method is wide applications to the analysis of the slope stability. The finite element method not only can carry on an appraisal quantitative of slope stability, but also can consider the discontinuity in rock, the relationship of the non-linear characteristics of stress and displacement, and mechanical anisotropy of rock. FEM can calculate elastic distortion and destruction state of rock. It can also take account into stress or constructing stress between structure surfaces, as well as some function and influence of specified conditions.This paper briefly reviews and comments the analytical methods of the rock slope stability. The basic principles of the nonlinear FEM for the stability of the rock slopes are systematically investigated, and the nonlinear FEM appled to analyse of the rock slope stability of the left bank of a right flushing & flood relief low-level outlet for a large-scale hydro power project. Local area on the left side of the right flushing & flood relief low-level outlet was cut by structure surfaces, the rock is a poor integrity and the rock mechanics parameters are low. The slope stability before and after excavation directly relate to the works’ safety, the construction progress and the budget. In view of this, it is necessary to undertake a comprehensive evaluation of the slope stability.The normal and tangential stresses of a sliding surface can be directly obtained from FEM results, which can avoid the artificial assumptions and overcome most shortcomings of the limit equilibrium analysis methods. The results of the study show that the method based on FEM can accurately assess and predict the rock block stability and possible sliding trends.更多还原