浅部和深部工程区地应力场及断裂稳定性比较

为研究浅部和深部工程区构造应力场的差异，依据优化处理后的浅部376组和深部619组实测地应力数据，采用回归分析法和断裂摩擦滑动准则对浅部和深部的地应力场特征及断裂稳定性进行比较分析.结果表明，与浅部相比，深部地应力场有从构造应力场向垂直应力场转变的趋势.深部的主应力与深度的线性相关程度比浅部的高.随着深度的增加，浅部的侧压系数KH1、Kh1分别向1.54、0.85趋近，深部的侧压系数KH2、Kh2分别向1.15、0.85趋近.浅部、深部的水平差应力η1、η2整体上随深度增加有增大的趋势.滑动摩擦系数μ取1.0时，浅部和深部断裂基本处于相对稳定状态；μ取0.6时，浅部逆断层有较大的滑动可能性，深部断裂滑动失稳的可能性较小；μ弱化到0.4、0.2时，浅部和深部断裂发生滑动失稳的可能性显著增加.浅部和深部断裂滑动失稳标准分别取μ为0.6~1.0、0.4~0.6较合适，逆断层和走滑断层的滑动失稳标准可以分别取μ为0.6、0.4左右.
In order to study the difference of tectonic stress field between shallow and deep engineering areas, the in-situ stress field characteristics and fault stability of shallow and deep rocks were analyzed and compared by regression analysis and fault friction slip criterion based on the measured in-situ stress data of 376 groups from shallow rocks and 619 groups from deep rocks after optimized processing. The results show that the stress field in deep rocks has a tendency to change from tectonic stress field to vertical stress field. The linear correlation between the principal stress and the depth in the deep rocks is higher than that in shallow rocks. With the increase of depth, the lateral pressure coefficients KH1, Kh1 of shallow rocks approaches 1.54, 0.85, respectively, while KH2, Kh2 of deep rocks are approached to 1.15, 0.85, respectively. The horizontal differential stresses (η1, η2) in shallow and deep rocks have the increasing trend with depth on the whole. The shallow and deep faults are mainly in stable state when the friction coefficient μ is 1.0, while the shallow thrust fault has large sliding possibility and the possibility of deep fault slip instability is smaller as μ is 0.6. When μ is weakened to 0.4 or as low as 0.2, the sliding possibility of shallow and deep faults increases significantly. In the slide stability criterion, μ may be selected as 0.6-1.0 or 0.4-0.6 for shallow or deep fracture and as about 0.6 or 0.4 for reverse or normal fault.