增量位移反分析方法在拉西瓦地下厂房中的应用

由于位移量测具有方便、准确和经济的特点，因而位移反分析法在地下工程领域获得了广泛的应用。以拉西瓦地下厂房的开挖过程为实际工程背景，应用从奥地利引进的大型岩土工程数值仿真分析系统FINAL为平台，建立了模拟分层开挖的有限元模型。采用主厂房第3层开挖前后洞壁围岩关键点的增量位移对厂区初始地应力场及围岩弹性模量进行了反演，最后利用反演结果对后续开挖过程中围岩的稳定性进行了预测。反分析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。

Application of incremental displacement back analysis to underground power-house of Laxiwa Hydropower Station

The displacement from back analysis has been extensively applied to underground projects because it can be measured conveniently, accurately and economically. A dynamic multi-step finite element model is established to simulate the excavation process of Laxiwa underground power-house using the large software FINAL which is introduced from Austria. The data of incremental displacement during the third layer’s excavation are applied to back analysis with the established finite element model to calculate parameters of initial geostress and elastic modulus. Finally, the results of back analysis are used to predict the stability of surrounding rocks during the later excavation. The comparison between computed and measured incremental displacements show a good coincidence, so as to prove the feasibility of the method.