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对不同倾角层理下的块裂结构岩质地下洞室进行了物理相似模拟试验,得到了洞室上覆岩层的运动行为和松动区变化规律,并对松动区界限建立了初步数学模型。试验结果表明:①当层理倾角小于岩块摩擦角时,岩层发生离层,各层内的部分岩块整体性沿节理面滑落;顶部松动区的左右界限为层理面和节理面构成的两个台阶面,上部界限为一层理面,台阶面倾角由块裂岩体的构造特征决定,上限可由改进的Voussoir梁模型计算得到,松动区内块体群作为一个整体,表现在块体理论上即为可动块体;②当层理倾角大于岩块摩擦角,而小于围岩自稳极限角时,洞室上覆岩层不发生离层现象,松动区内块体群整体性自由掉落;松动区左右界限为两个台阶面,上限为一层理面,但此时,界限附近部分岩块发生转动,可形成有效的压力拱,从而保证上覆岩层的稳定性;③当层理倾角大于围岩自稳极限角,洞室顶部松动区可确定为两组层理面所围成的区域,在松动岩体整体性沿节理面滑落的过程中,有部分块体受力状态改变,发生转动行为,从而出现岩块挤压现象,可阻止松动岩体整体性滑落。
Physical simulations of rock mass underground caverns under different bedding tiers are carried out. The movement behavior of overburden caverns and the variation of loosening zone are obtained. The preliminary mathematic model of the loosening zone is established. The results show that: (1) When the bedding inclination is less than the rock friction angle, the strata of the rock strata are separated, and the integrity of some rock blocks in each strata slides along the joints; the left and right boundaries of the top loosening zone are composed of bedding and jointing surfaces The upper boundary of the two steps is a bedding plane. The dip angle of the step face is determined by the structural features of the boulder rock mass. The upper limit can be calculated by the improved Voussoir beam model. The lump group in the loosening region is shown as a whole, In theory, it is a movable block. ② When the bedding inclination is greater than the friction angle of the rock mass and less than the limit of self-stability of the surrounding rock, the overlying strata of the cavern do not delaminate, and the bulk group in the loosening area is free Falling; loose area left and right boundaries for the two steps, the upper limit of a layer of face, but at this time, some rocks near the boundaries of rotation, the formation of effective pressure arch, so as to ensure the stability of overlying strata; The bedding inclination is larger than the limit of self-stability of surrounding rock. The loosening area at the top of the cavern can be identified as the area enclosed by two sets of bedding planes. During the sliding of the loose rock mass along the joint plane, some blocks are stressed Change of state, the occurrence of rotational behavior, resulting in rock squeeze Phenomenon, can prevent loose rock fall integrity.