丹江口库区初始地应力场的反演

Derivation of the initial crustal stress field in the Danjiangkou Reservoir Area

根据丹江口库区的地质构造,考虑断裂破碎带和岩石力学参数随埋深变化,建立计算模型,反演分析了库区的初始地应力场,结果表明:1)库区地应力的临界深度在1km埋深附近;2)水平方向两个主应力,在埋深750m范围内X轴方向为主压应力,随埋深由13MPa增至23MPa,Y轴方向为主拉应力,随埋深由12MPa减至0,埋深750m以下两个坐标轴方向均为主压应力且随埋深增加;3)两个水平主应力差在埋深10km范围内随埋深基本呈线性增加,大约10km深处急剧减小,20km以外基本消失,岩体处于静水压力状态.

According to the geological background of the Danjiangkou reservoir, the computation model was firstly developed con- sidering the changes in depth of fracture zones and the mechanical properties of the rock. The initial crustal stress field of the res- ervoir area was derived, which suggests that： 1） The critical stress depth of the reservoir area is roughly 1 kin; 2） Above depth of 750m, the horizontal principal stresses in X axis direction are compressive and increases from 13 MPa to 23 MPa along the depth; and the principal tensile stress in Y axis direction reduces from 12 MPa to 0 along the depth. Below the depth of 750m, the three principal compressive stresses increase along the depth; 3） Above the depth of 10 km, the difference of the two horizon- tal principal stresses increases linearly along the depth. However, it reduces suddenly at the depth of about 10 km and disappears below the depth of 20 km, where the rock is under the hydrostatic stress state.