丹江口库区水压应力场的有限元模拟

Finite-element simulation of hydraulic-pressure stress field in Danjiangkou Reservoir area

根据丹江口水库区的地质特征建立三维有限元模型模拟计算水压应力场和应变场,分析水库蓄水后断层的稳定情况及库水载荷对库盆岩体中应力应变状态的影响,并预测丹江口水库二期工程诱发地震的可能性与危险区。研究结果表明,库水载荷不可能直接诱发水库地震,而是通过对岩石的软化和断层的润滑间接诱发地震。蓄水后瓦房厂—周山断裂出现张开现象,丹江断裂滑移增大,稳定性降低;均郧断裂和公路断裂面压应力增加,滑移减小,从而变得更加稳定。水库二期工程后汉江库区诱发地震的机率很小,但丹江口库区有可能诱发地震,可能性较大地区为厚坡、九重、彭桥、仓房和田川。

The 3-D finite element model for analyzing the hydraulic-pressure stress-strain field of Danjiangkou Reservoir area is established according to the geological characteristics. The stability of faults and the influence of water load on stress state of reservoir rock mass after the reservoir impoundment are analyzed. Furthermore, the probable reservoir induced earthquake and the regions with potential risk are predicted. The analysis shows that the load of reservoir water will not induce earthquake directly, but it will result in the softening of rock or slip of faults and leads to indirect earthquake. The possibility of induced earthquake occurred to the Hanjiang River storage region in the second stage project of the Danjiangkou Reservoir is insignificant, but the possibility of the Danjiang River storage region is much higher.