卡拉水电站地下厂房初始应力场反演分析

初始地应力场特征是地下工程稳定分析中最重要的条件，为了评价开挖后地下洞室的围岩稳定及支护设计的长期安全，需要对围岩的初始地应力场进行反演。在对雅砻江卡拉水电站工程区地应力实测值进行分析的基础上，根据世界地应力图和GPS地表监测数据所确定的区域地应力特征，选取地下厂房区域测试可靠、具有代表性、离厂房区域较近的实测点作为初始地应力数值反演分析的回归对象，结合反演分析原理，获得整个地下厂房区域的地应力场分布特征。通过对比数值计算值和实测成果可知：测点地应力的大小和方向拟合程度较好，分布规律大致相同，表明采用数值反演分析方法的合理性。分析成果为地下厂房洞室群的布置、开挖支护设计等提供了依据。

Inverse analysis on in-situ stress of underground powerhouse of Kala Hydropower Station

The characteristics of in-situ stress are the most important loads for the stability of underground engineering. In order to evaluate the rock stability of underground caverns after excavation and the long-term safety of the support system, it is necessary to inverse the in-situ stress. Based on the analysis of the geo-stress testing results in the region of underground powerhouse of Kala Hydropower Station on Yalongjiang River, according to the regional in-situ stress characteristics determined by the world stress map and surface monitoring data of GPS, the points that were reliable, representative and close enough to the powerhouse were selected to do the inverse analysis. Combined with the principle of inversion, the distribution characteristics of the in-situ stress in the entire underground powerhouse area were obtained. Through comparative analysis between the numerical calculation values and the measured results, it is found that the magnitude and direction of the in-situ stress were well fitted, and the distribution characteristic was almost the same, indicating the numerical back analysis method was reasonable. The analysis results provide a basis for the layout of underground caverns and the design of support and excavation.