复杂缓倾角岩体边坡的三维稳定性分析

为了建立复杂缓倾岩体边坡的三维稳定性分析方法，以含有层面和多组结构面的缓倾角岩体边坡为研究对象，根据现场调查资料将缓倾角岩体边坡相邻岩块间的接触关系分为脱离、面接触和线接触3种模式，依据每种岩块接触方式构建相应的接触力学模型，明确岩块的受荷情况，基于材料力学以岩块的竖向位移和转角为中间变量建立3种接触情况下的层间荷载计算方法。根据各岩块受到的荷载，推算出岩块后部结构面处的拉应力、剪应力和扭矩计算式，再基于断裂力学方法获得了该结构面的第1，2和3型应力强度因子，进而获得结构面的联合应力强度因子计算表达式。将结构面的断裂韧度与联合应力强度因子的比值作为各岩块的稳定系数，通过比较该岩块稳定系数与1的大小关系判断各岩块是否稳定，并将该分析方法应用于綦江羊叉河缓倾角岩体边坡。研究结果表明：该方法计算获得的坡顶破坏位置与现场边坡已经开裂的位置基本一致，说明该方法基本可行；改变岩块后部结构面贯通段的长度和弹性模量，稳定系数变化幅度达分别为74.32%和16.45%，不考虑Z方向各列岩块的相互影响岩块的稳定系数将增大5.16%~11.72%；研究结果可为缓倾岩体边坡的防治提供初步的理论支撑。

Three-dimensional Stability Analysis of Complex Gentle Incline Rock Slope

In order to establish the three-dimensional stability analysis method of complex gentle incline rock slope,the gentle incline rock slope which includes stratum and multi-group structural plane was taken as the research object. Firstly, according to the survey data of field, the contact relationship of adjacent rock blocks of gentle incline rock slope was divided into detachment, surface contact and line contact. According to the contact method of each rock, the corresponding contact mechanics mode was constructed, and the load-bearing condition of the rock was also defined. Based on the material mechanics, the calculation method of interlayer load in three kinds of contact cases was established by regarding vertical displacement and the corner of rock as intermediate variables. Then, according to the load of each rock, the tensile stress, shear stress and torque at the rear structural plane of rock were calculated. The first, second and third type of stress intensity factors of the structural plane were obtained based on the fracture mechanics method, and further, the calculated expressions of the combined stress intensity factors of the structural plane were obtained. Finally, the ratio of the fracture toughness of the structural plane to the joint stress intensity factors was used as the stability coefficient of each rock. By comparing the relationship of size between the stability factor of the rock and 1, whether the blocks are stable could be judged. The method of this paper was applied to gentle incline rock slope of Yangcha River in Qijiang。The results show that the location of the top-slope failure calculated by the calculation method in this paper is basically consistent with the location where the on-site slope has been cracked, which means that the three dimension stability analysis method of complex gentle incline rock slope is reasonable. Therefore, the method constructed in this paper can provide primary theoretical support for the prevention and control of the gentle incline rock slope.