区域非稳定动力学环境下的岩体松动效应

RELAXED EFFECT OF ROCK MASS IN DYNAMIC CONDITIONS OF REGIONAL INSTABILITY

区域非稳定动力学环境下,长期的构造变形、重力卸荷以及地震动力作用的共同影响,可以导致岩体发生大范围变形、松动。松动岩体内发育大量的软弱结构面,且表现出整体破碎、松弛严重、透水强烈,张性节理裂隙发育、地表裂缝较发育、岩体地震动力破坏信息反映明显等特征。岩体的变形松动可以分为卸荷变形松动、倾倒变形松动、顺层滑移松动、断层控制松动、节理裂隙控制松动等5种模式。岩体的物理振动试验结果表明,地震动力是造成岩体松动的主因。数值模拟结果表明,在单纯自重应力影响作用下,松动岩体不会出现大面积的失稳破坏现象,但在地震动力作用下,松动岩体会发生大面积屈服破坏。

Collective effect of long - term structure deformation, unloading and earthquake can result in large - scale deformation and looseness of rock mass under the dynamic condition of regional stability. Large number of weak structural planes developed in relaxed rock mass. The rock mass is completely cracked, very relaxed, highly permeable. Much open -joint and ground fissure exist in the rock mass. The information of the rock breakage is very distinct under the paleo - earthquake. Deformation - relaxed types of relaxed rock mass may be divided simply into five models ： i.e. unloading deform - relaxation, toppling deform - relaxation, bedding - slip relaxation, deform - relaxation controlled by faults and relaxation controlled by cranny / joint. The vibration test of dynamic models of rock mass indicates that the earthquake power is the main factor of relaxed effect of the rock mass. The result of numerical simulation shows that large -scale Instability and failure would not occur in the relaxed rock mass under self- weight stress, but it would occur under the earthquake power.