黄河小浪底水库工程坝区构造应力场的恢复和分析

Return and Analysis of Structural stress Field in Xiaolangdi Dam Site Area

根据小浪底坝区的构造形迹,利用断层错动机制解,共轭节理赤平投影解和地震震源机制解三种方法,对坝区存在的构造应力场进行恢复,并对坝区各期构造运动的应力场构造对和坝区地质构造的成因进行了分析。结果表明,坝区的构造形迹具有多期性和继承性,前期后期构造的控制和干扰,后期构造对前期构造的继承、改造和叠加,使小浪底坝区的工程地质条件非常复杂。只要抓住应力场这条线索,才能查清坝区工程地质条件,并能准确地分析水库运行期的坝体稳定性。

According to the structural features of Xiaolangdi dam site area, the structural stress field can be returned using the fault slippage mechanism analysis, stereographic projection analysis of conjugate joints and focal mechanism analysis methods respectively, and the causes how the fields during different tectonic movement periods wereformed have been analysed too. It is concluded that the structural features in the area were formed by several periods and bore inheritance, i.e. the earlier tectonic movement controlled the later one and the later one inherited, changed, added the earlier one, which resulted in the extremly complicated engineering geological condition of Xiaolangdi dam. Only the stress fields are found out, can the engineering geological condition in the area be confirmed and the stability of the dam be analysed accurately.