增量位移反分析在水电地下洞室工程中的应用

反分析是确定计算模型参数的有效方法.通常多采用量测所得全量位移进行反演计算.但地下工程中许多量测数据为增量位移,且实际施工过程可以通过建立分步开挖的有限元模型来模拟.据此,结合某水电站地下洞室工程中地下厂房的开挖,建立了模拟动态施工的有限元模型,利用某一开挖步施工前后量测值之差,采用增量位移优化反分析方法对洞室附近初始地应力场及围岩弹性模量进行了反演.计算所得增量位移与实测值符合较好,表明了这种方法的可行性.同时,根据分析结果对该方法进行了评价.

Application of incremental displacement back analysis to hydropower station underground caverns

Back analysis is an efficient method to achieve parameters of computing mode and complete displacement is often used in the method. However, during measurement in underground engineering, many data of incremental displacement are achieved and the real construction process can be simulated by multi-step finite element model. So a dynamic multi-step finite element model is established to simulate excavation process of caverns in a hydropower station . Then data of incremental displacement are applied in back analysis with the established finite element model to calculate parameters of initial geostress and elastic modulus. The incremental displacements calculated with these parameters agree well with those measured, which proves the efficiency of the method. Finally the method is evaluated on the basis of the results.