边坡潜在滑移面关键单元岩体裂隙演化特征细观试验与滑移机理研究

 利用自行研制开发的剪切蠕变细观试验装置与软弱煤岩细观力学特性测控软件，对边坡潜在滑移面关键区红砂岩进行了系统的剪切蠕变试验研究，分析了红砂岩在不同载荷水平的剪切蠕变作用下细观裂纹扩展的时空演化规律及破坏后破裂面形态特征与剪切蠕变强度之间的关系，初步探讨了边坡的滑移机理。结果表明：剪切蠕变作用下，红砂岩宏观蠕变变形与细观裂隙扩展同步进行；红砂岩裂纹扩展方向与剪切应力方向具有一定偏差，且出现多次分岔；裂纹多为绕晶体边缘扩展，扩展路径的不规则性受到岩体晶体分布特征的影响；岩体不同成分之间的应力响应差异、变形不协调和微裂隙之间的相互作用促进了裂隙的萌生和扩展，裂隙多在张拉和剪切共同作用下形成；破裂面粗糙度与剪切蠕变强度呈非线性递增关系，曲率呈先增大后减小趋势。

EXPERIMENTAL STUDY ON MICRO-CRACKS EVOLUTION CHARACTERISTICS OF KEY ROCK UNIT OF SLOPE POTENTIAL SLIP SURFACE AND ANALYSIS ON SLOPE SLIP MECHANISM

Tests on red sandstone under shear creep condition were done with both self-developed shear creep microscopic testing device and monitoring software of coal or rock micromechanics properties. Micro-cracks temporal and spatial evolution law of red sandstone under shear creep condition and the relationship between morphological properties of rupture surface and shear creep strength were analyzed. Slope slip mechanism is discussed in this paper，too. The results show that creep deformation and micro-cracks propagation were developed simultaneously under shear creep condition；the propagation direction of micro-cracks has bias in some degree compared with shear stress，and multiple bifurcations occur in the process of crack propagation；most cracks are along grain boundary，and the irregularity of crack propagation path is affected by the distribution of rock grains；micro-cracks are mostly formed by tension and shear together and the differences of stress response and inconsistent deformation between different components of rock and the interaction of micro-cracks promote the initiation and propagation of micro-cracks. Relation curve between roughness of rupture surface and shear creep strength is non-linear increasing，and the curvature increases at first then decreases.