瓜什则盆地的地应力场分析与模拟

基于水压致裂法地应力测试的原理,系统性研究分析了瓜什则盆地区域内的地应力场特征,这为成宁铁路控制性工程甘青特长隧道的选线设计提供了重要的参考依据。首先,根据区域内钻孔的地应力测试结果,采用有限元方法进行了区域地应力场的三维数值模拟,确定了该区域内的水平应力大于垂直应力的基本特征;其次,根据多个水平构造应力场的水平切片,分析了水平构造应力场随深度的变化,说明了该区域内水平构造应力场具有由东北向西南挤压的应力变化特征;然后,根据区域岩体抗拉强度分布,发现该区域内存在一个低抗拉强度带,它的地层结构相对较复杂,且其工程地质特征主要表现为地层破碎带或断层;最后,采用最小二乘法拟合了CK方案隧道横截面最大切向应力与最大水平主应力的线性回归模型,并预测了该方案隧道地层的岩爆发育程度。

Analysis and Simulation of In-situ Stress Field of Guashize Basin

Based on the principle of geostress measurement by hydraulic fracturing method,the characteristics of in-situ stress field of Guashize basin regions are systematically studied and analyzed.This provides an important reference for the selection of Chengning railway line.Firstly,the 3-D numerical simulation of the regional stress field is carried out based on the stress test results of the borehole in the region.The basic characteristics of in-situ stress field in this area are determined.Secondly,the change of the horizontal tectonic stress field with the depth is analyzed according to many horizontal slices of the horizontal tectonic stress field.The change shows that the horizontal tectonic stress field in the region is characterized by stress change from northeast to southwest.Then,according to the distribution of tensile strength of rock mass in the region,it is found that the region is in a low tensile strength zone,and its formation structure is relatively complex,and its geological characteristics are mainly characterized by formation breakage or fault.In the end,the least square method is used to fit the linear regression model about the maximum tangential stress of the CK tunnel cross section and maximum horizontal principal stress,and the development of rockburst is predicted.