断层周边应力场的原位实测及数值反演

Measurement and Back Analysis on the Initial Rock Stress Field around the Faults

在分析断层周边实测应力分布特点的基础上，通过建立ＦｒｉｃｔｉｏｎｌｅｓｓＮｏ－ｔｅｎｓｉｏｎ参数式数值模型，采用位移不连续数值方法模拟评价了复杂断层扰动下的非均匀原岩应力场，得到了与实测应力分布特征高度吻合的计算结果，并比较分析了断层对其周边区域应力状态的影响．结果表明：原岩应力状态的空间分布主要受其邻近断层的支配，应力场的扰乱范围与断层的几何尺寸密切相关；非连续地层区域的原岩应力状态及应力扰乱程度随空间位置而异，具有各向异性及非线性的分布特征；由于断层对原岩应力的扰乱作用，有限“点”的实测值不能全面反映构造应力场的全貌。

Based on the analysis on distribution characteristic of initial rock stress measurements around the faults, structural rock stress field is simulated and estimated by applying displacement discontinuity method and establishing frictionless no tension numerical model in the paper.The calculating results fit with the distribution characteristic of the measurements.And influence of the faults on initial rock stress statement is analyzed by comparing the in suit measurements around faults with its numerical calculating results.It is shown that the distribution of initial rock stress is effected by its near faults and its focal zone stress depends upon the scale of the fault.Initial rock stresses in discontinuous underground change with the calculating position and show the aeolotropical characteristic.Numerical simulation is very important to analyze and estimate the rock stress field.