隧道应力扰动区地应力测试及反演研究

Research on crustal stress measurement and inversion of stress disturbed area of a tunnel

通过对隧址区地应力的调查和现场测量,初步确定该区域存在较大的构造应力,但因岩芯破碎,只获得隧道应力扰动区的应力实测值。为此在三维数值模拟过程中模拟了河谷的下切过程,以反映地形对应力场的影响,并采用试算的方法调整侧压系数,从而确定合理的初始应力,使试算结果与现场测量的数据基本吻合,最终确定出合理的侧压系数和初始地应力的数值,弥补了现场测量的不足。研究结果表明,隧道轴线各点的地应力与隧道的埋深、地形地貌有关,且在K42段处于极高的应力状态,为隧道的开挖、支护及稳定性分析提供了科学依据。

Through investigation and in-situ measurement of crustal stress in tunnel location, rather large tectonic stress is ascertained in the tunnel region at first. Because of core sample break, only stress of disturbed area is measured in the tunnel. In the process of 3-dimension numerical modeling, the course of vertical erosion by the Wujiang River is modeled in order to reflect the effect of topographic form on crustal stress. And using the method of pilot calculation to adjust coefficient of horizontal pressure, then appropriate initial stress is determined. Making calculated results coincide with the data measured in-situ, the rational coefficient and crustal stress is obtained. Numerical calculation covers the shortage of in-situ measurement. The research results show that crustal stress of tunnel axis varies with embedded depth and topographic features; and the section K42 is of very high stress. The results provide a scientific foundation for analyzing excavation, support and stability of tunnel.