基于离心机和数值模拟的软硬互层反倾层状岩质边坡变形特征分析

我国西部山区建设揭露了众多大型弯曲倾倒变形体，它们多具有软硬互层结构。为进一步探明软硬互层反倾岩质边坡的变形破坏规律，本研究融合大型土工离心机试验与自开发的可以综合考虑节理面拉剪和压剪破坏的Hoek-Brown与Mohr-Coulomb联合强度准则，对此类边坡进行试验与数值模拟分析。首先，结合监测点位移和应力曲线对边坡的变形破坏过程进行详述并验证了所提出的强度准则及所建立的数值模型的正确性；然后，基于此数值模型研究不同几何因素对此类边坡倾倒破坏特征的影响。结果表明:（1）节理单元采用Hoek-Brown与Mohr-Coulomb联合强度准则可以较准确地模拟软硬互层反倾边坡的层间错动以及岩层弯折；（2）此类坡体倾倒变形破坏全过程为:层间先出现相互错动，然后边坡自坡脚部位开始出现弯曲变形，随后坡体后缘出现拉张裂缝，与此同时边坡整体向临空面弯曲倾倒，最终形成2个或3个破坏面；（3）随着岩层倾角的增大，边坡一级破坏面逐渐向坡体深处发展；（4）随着硬/软岩层厚比的减小，坡顶竖向位移变小，且坡体滑动的整体性逐渐增强；（5）随着软/硬岩层厚比的增加，坡体破坏面逐渐由粗糙的“锯齿状”向平滑的“圆弧状”过渡。

An analysis of the deformation characteristics of soft-hard interbedded anti-tilting layered rock slope based on centrifuge and numerical simulation

The construction in mountain areas in western China has revealed many large-scale bending toppling deformation bodies, and most of them are of soft and hard interlayer structures. In order to further explore the deformation and failure law of anti-dumping soft-hard interbedded rock slope, this study combines the large-scale geotechnical centrifuge test and the joint strength criterion of Hoek-Brown and Mohr-Coulomb, considering the tension-shear and compression-shear failure of the joint surface to carry out test and numerical simulation analysis for this kind of slope. The displacement and stress curve of the monitoring point are combined, the deformation and failure process of the slope is described in detail and the correctness of the proposed strength criterion and the numerical model are verified. Based on this numerical model, the influence of different geometric factors on this kind of slope is examined. The results show that the joint strength criterion of Hoek-Brown and Mohr-Coulomb can accurately simulate the interlaminar dislocation and rock bending of anti-dumping soft-hard interbedded rock slope. The whole process of toppling deformation and failure of this kind of slope is as follows: the interlayer first dislocates, then the slope begins to bend from the foot of the slope, the tension crack appears at the back edge of the slope, and at the same time the slope as a whole bends to the empty surface. Finally, 2 or 3 failure surfaces are formed. With the increase of the dip angle of the rock layer, the first-order failure surface of the slope gradually develops to the depth of the slope. With the decrease of the thickness ratio of the soft/hard strata, the vertical displacement of the top of the slope becomes smaller, and the integrity of slope sliding increases gradually, and with the increase of the thickness ratio of the soft/hard strata, the failure surface of the slope gradually changes from rough 'sawtooth' to smooth 'arc'.