鲜水河构造带某隧道地应力反演与分析

地应力的分布规律严重影响地下工程建设，获得开展工程区域地应力场分布对指导支护结构的设计具有重要意义.在鲜水河断裂带某隧道工程区采用钻孔水压致裂法进行了深孔地应力测试，基于地应力测试结果，得到了开展工程区域地应力随深度的变化规律，并利用数值模拟进行地应力反演. 结果表明:地应力随深度的增加而逐渐增加，其中最大水平地应力的递增梯度为0.385 MPa/km，最小水平主应力递增梯度为0.257 MPa/km；隧道纵断面水平最大主应力为41.69 MPa，最小主应力为29.84 MPa，侧压力系数为1.363～1.438，围岩应力以水平应力为主；地应力在断层部位得到了一定程度的释放，断层两侧的完整岩体应力存在一定程度的集中，应力值较高. 

Back-Calculation of In-situ Stress of Railway Tunnel in Xianshuihe Fault Belt

The distribution law of ground stress has a very important role in the construction of underground engineering, and obtaining the distribution of ground stress field in the construction area is of great significance to guide the design of support structure. The borehole hydraulic fracturing method was used to test the in-situ stress in the project area of a railway tunnel in Xianshuihe fault belt. Based on the in-situ stress results, the variation law of in-situ stress with depth was obtained and the in-situ stress inversion was carried out by numerical simulation. The results show that the in-situ stress increases gradually with the increase of depth, in which the increasing gradient of the maximum horizontal in-situ stress is 0.385 MPa/km, and that of the minimum horizontal principal stress is 0.257 MPa/km. The maximum and minimum horizontal principal stress values of the tunnel profile are 41.69 and 29.84 MPa, respectively. The lateral pressure coefficient is 1.363?1.438, and the surrounding rock stress is dominated by horizontal stress. Generally, the in-situ stress has been released to a certain extent in the fault area, and the stress of the intact rock mass on both sides of the fault is concentrated to a certain extent with a high stress value.