陡倾角层状岩体中地下洞室围岩的变形

Deformation of huge underground opening excavated in layered rock mass with steep dip angle

考虑到层状岩体顺层滑移和弯曲变形的特点,将Cosserat介质理论引入到大型地下洞室的开挖模拟中,基于Matlab编制了考虑偶应力的有限元程序,并对一个简单地下洞室模型进行模拟分析。结果表明:洞周围岩的变形随层面间距的增大而减小,洞室变形的不对称性在层面间距越小的情况下越明显;大型洞室高边墙的位移随层面倾角先增大后减小,反倾向一侧的位移在倾角为60°达到最大,而顺倾向侧边墙在30°达到最大;在洞室的同一高度处,当岩层倾角缓时顺倾向侧洞周位移要大于反倾向侧的位移,而当倾角变陡后,顺倾向侧洞周位移要小于反倾向侧的位移;层面的切向刚度对洞周位移影响很大,洞周位移随切向刚度系数的减小而迅速增大,但切向刚度系数减小到一定程度后将趋于稳定。数值模拟表明用Cosserat介质来模拟层状岩体是合适而且方便的。

Considering the special characteristics of steep inclined layered rock, this paper introduced Cosserat continuum theory to simulate excavating huge underground openings in layered rock mass. A program based on this theory was written in Matlab, in which the couple stress is taken into account. The modeling of a simple underground opening excavated in layered rock mass was carried out. The results show that with the decreasing of space between layers, the deformation of surrounding rock increases and tends to more unsymmetrical; with the increasing of dip angle, the deformation increases first but then decreases, and when the dip angel is 60°, the deformation of anti-inclined wall come to a head, whereas the maximum deformation of the other side wall is got when the dip angel is 30°. At the same height of the opening, the deformation of inclined wall is larger than that of anti-inclined wall when the dip angle is gently, whereas the deformation of anti-inclined wall is smaller than that of inclined wall when the dip angel is steep.The deformation is effected by the shear stiffness greatly, but when it reduces to certain degree, the deformation will be stable. The numerical modeling indicates the Cosserat continuum theory is suitable for simulating excavating underground opening in layered rock mass, and it is simple and convenient. 1 tab, 10 figs, 7 refs.