基于离心试验的反倾层状岩质边坡内非贯通性裂缝变形特性分析

坡体内不同部位结构面间岩桥断裂扩展导致了反倾层状岩坡的破坏。为研究坡体内非贯通性裂缝断裂扩展对坡体演化的控制作用，以苗尾水电站右坝肩倾倒变形体为地质原型，开展含多组非贯通性裂缝的反倾层状岩质边坡离心模型试验，分析反倾层状岩质边坡内非贯通性裂缝变形特性。结果表明：（1）坡体内含非贯通性裂缝的岩层断裂最终呈现为裂缝间岩桥贯通、缓倾裂缝与上岩层贯通、陡倾裂缝与下岩层贯通、陡倾裂缝与缓倾裂缝端口处贯通及非裂缝处岩层发生断裂等5类裂缝断裂模式，并以裂缝间岩桥贯通为主要断裂模式；（2）基于断裂力学并结合裂缝断裂叠加原理，主折断面处岩层的不稳定系数在坡高1/3处最小，并向坡脚和坡顶两侧逐渐变大，而应力强度因子由坡高1/3处向坡脚和坡顶处逐渐变小；（3）裂缝的断裂扩展控制着坡体演化，并受裂纹率及裂缝周围的尖端应力场影响较大。在坡体演化初期，以坡体后缘压缩沉降和局部岩层裂缝压剪破坏为主，岩层倾角发生较大变化，呈现由坡体上部往下逐级变大的趋势；演化中期，坡体后缘裂缝扩展形成主折断面，坡体中上部岩层角度变化较大，裂缝断裂数目的继续增加；演化末期，裂缝断裂数目保持平稳，主要以断裂岩层的位置重分布为主要变形特征...

An analysis of non-penetration cracks in anti-dip rock slope based on centrifugal test

The fracture extension of rock bridges between structural surfaces in different parts of the slope leads to the damage of the anti-dipping laminated rock slope. In order to study the controlling effect of fracture extension of non-penetrating fractures in the slope on the evolution of the slope, the centrifugal model test of the anti-dipping laminated rock slope containing multiple groups of non-penetrating fractures is carried out with the right shoulder of the Miaowei Hydropower Station as the geological prototype to analyze the deformation characteristics of non-penetrating fractures in the anti-dipping laminated rock slope. The results show that the fractures of rock formations containing non-penetrating fractures within the slope finally show five types of fracture patterns, including inter-fracture bridge penetration, penetration between gently dipping fractures and the upper rock layer, penetration between steeply dipping fractures and the lower rock layer, penetration between steeply dipping fractures and the port of gently dipping fractures, and fracture of rock layers at non-fractures, with inter-fracture bridge penetration as the main fracture pattern. Based on fracture mechanics and combined with the principle of fracture superposition, it is found that the instability factor of the rock layer at the main fracture section is the smallest at 1/3 of the slope height and gradually becomes larger towards the foot and both sides of the slope top, while the stress intensity factor gradually decreases from 1/3 of the slope height to the foot and the top of the slope. The fracture extension of cracks controls the slope evolution and is greatly influenced by the crack rate and the tip stress field around the cracks. At the early stage of slope evolution, the compression and settlement of the back edge of the slope and the compression and shear damage of the local rock cracks are the main features, and the dip angle of the rock layers changes greatly, showing a trend of becoming larger from the upper part of the slope to the lower part of the slope. At the middle of the evolution, the fracture extension of the back edge of the slope forms the main fracture surface, and the angle of the rock layers in the middle and upper part of the slope changes greatly. At the end of the evolution, the number of fractures remains stable, and the main deformation feature is characterized by the redistribution of the location of fractured rock layers, the formation of secondary fracture surfaces, further compression between broken rock layers, and further destabilization of the slope body.