鹧鸪山隧道地应力反演模型与三维地应力

Zhegu Mountain tunnel ground stress inversion model and three dimensional ground stress

结合四川汶川-马尔康高速公路鹧鸪山隧道地应力现场测量资料,分析与之紧邻的317国道鹧鸪山隧道实测地应力资料,采用Surfer软件为过渡平台,生成更为快速精细的三维地质模型。通过ANSYS对地层划分和浅表层生成处理后导入FLAC3D,同时考虑了河谷下切时空演变过程对山体地应力的影响,对汶马高速公路鹧鸪山隧道地应力反演与研究获得了初始应力场资料。通过分析区域构造特征、实测数据和以往研究成果,经多次试算后得出,在重力场模型上,在两个水平方向的竖向边界上同时施加对称梯度应力,所取得的拟合效果最好。数值模拟也验证该隧道最大主应力方向主要在N50°W^N70°W,隧道埋深0.8~1.35 km范围内存在高地应力场。

This paper analyzes the data about the ground stress of the Zhegu Mountain tunnel on 317 national highway in Sichuan. This tunnel is close to the Zhegu Mountain tunnel on the highway from Wenchuan to Maerkang. Combined with the measured data about the ground stress of the Zhegu Mountain tunnel on the highway, this paper builds a much quicker and elaborate 3-D geological model based on Surfer platform. This model is introduced into FLAC3D after dividing strata and analyzing the shallow strata by ANSYS. Considering the influence of the evolution process when valleys incising down on the mountain ground stress, this paper eventually acquires the data of the initial stress field in the Zhegu Mountain tunnel through ground stress inversion and research. In the model of gravity field, the best fitting effects can be got if the symmetric gradient stresses are exerted on the vertical boundaries of the two horizontals after many trials and analyzing the geotectonic characteristics of this zone, the testing data and research results. The numerical simulation also verifies that the biggest primary stress dimension is mainly N50°W-N70°W. The high stress field exists within 0.8-135 km of the tunnel buried deep.