龙滩水电站左岸边坡二维位移反分析

论述了考虑开挖卸荷效应的二维位移反分析方法。对龙滩水电站左岸岩质边坡1-1剖面进行地质概化、施工开挖分区和开挖扰动分区,建立有限元计算模型。根据试验和现场实测资料,确定待反演得参数和取值范围,通过二维弹塑性有限元方法与神经网络-遗传算法相结合反分析出岩体力学参数。基于该参数的正分析计算结果表明,计算位移与监测位移趋势一致,量值吻合。开挖面附近最大压应力约为1.0MPa左右,开挖面附近基本上没有拉应力区。开挖完成后的塑性区主要分布在坡顶和开挖面及大断层附近,而且基本上发生在开挖损伤区和部分卸荷影响区。

Two dimensional displacement back analysis of left bank slope of Longtan hydropower station

A method of slope displacement back analysis considering excavation unloading effect is presented. In the stability analysis of section 1-1 of left bank of Longtan hydropower station, the geology generalization, excavation step and disturbing zone are analyzed to establish the computing model of finite element method. The mechanical parameters of rock masses are solved by using finite element method with neural network-genetic algorithm. The results of forward analysis with these parameters show that the displacements are reasonable and very agreement with the monitoring results. The maximum compressive stress is 1.0MPa and no tension stress at the excavation zone. The plastic zones are distributed at the slope top, excavation zone and near the big fault.