硬性接触型岩体结构面剪切特性及边坡稳定性分析
发布时间：2018-08-21 08:20
【摘要】：硬性接触的粗糙起伏型岩体结构面广泛发育于硬质岩体斜/边坡中，其剪切力学性质对边坡稳定性具有重要影响。由于岩体结构面现场直剪试验及取样比较困难，很难开展大尺寸岩体结构面剪切试验。论文依托国家自然科学基金面上项目（No.41172243）的资助，基于岩体结构面野外调查测量及室内加卸荷试验岩石试件主破裂面的高精度三维激光扫描研究了硬性接触型岩体结构面表面的宏-细观起伏形态特征，进而利用二维颗粒流(PFC2D)程序从细观角度模拟研究了起伏角及法向应力对贯通型锯齿状岩体结构面以及台阶高长比对贯通型单台阶状岩体结构面的剪切变形及强度影响规律，并将研究得到的经验强度公式应用于边坡稳定性的极限平衡法计算。研究成果不仅丰富了岩体结构面剪切力学性质及参数取值的岩体力学理论，也可为锯齿状和台阶状岩体结构面所控制的边坡稳定性评价提供有益参考。主要研究成果如下： ①岩体结构面表面起伏形态可概化为平直状、台阶状、锯齿状和波浪状四类。其粗糙度具有方差自相似性，可以用结构面剖面垂直方向的方差σ2D来描述结构面二维粗糙度系数，用整个结构面粗糙高度的方差σ3D来描述结构面三维的粗糙起伏。大理岩卸荷破裂面粗糙高度分布近似符合高斯函数分布规律，粗糙高度分布的偏度sk大多小于0，向右边偏斜较大。 ②锯齿状结构面的剪切变形模式可分为爬坡、爬坡啃断和啃断3种基本类型，随着锯齿起伏角和法向应力的增大，逐渐由爬坡、爬坡啃断向啃断模式演变，且这种递变随起伏角和法向应力具有近对称矩阵分布特征。锯齿状岩体结构面的剪切强度随法向应力及起伏角的增大均近线性增加，建立了同时考虑锯齿状结构面爬坡和啃断效应的剪切强度经验公式。 ③台阶状结构面的损伤破坏模式可分为压切破坏和张剪破坏两种类型，随着台阶高长比H/L的增大，结构面剪切过程中弯矩作用比例逐渐增大张性破坏成分逐渐增多，变形模式逐渐由压切破坏模式转换为张剪破坏模式。结构面最先在台阶角点处产生宏观裂纹，随着裂纹扩展方向的不同而逐渐转化为两种不同的损伤破坏模式。针对实际岩体结构面台阶高长比H/L常较小（压切模式），，建立了同时考虑结构面摩擦角增大和啃断效应的剪切强度经验公式。 ④将建立的锯齿状和台阶状结构面剪切强度经验公式运用于边坡稳定性极限平衡法计算的参数取值。基于FLAC数值模拟及强度折减法理论，研究了外倾贯通型锯齿状与台阶状岩体结构面控制的边坡滑移破坏的模拟及安全系数；对比强度折减法和极限平衡法安全系数计算结果，验证了剪切强度经验公式的正确性。
[Abstract]:The hard contact rough undulating rock mass structure plane is widely developed in the hard rock mass slope / slope, and its shear mechanical properties have an important effect on the slope stability. Due to the difficulty of direct shear test and sampling of rock mass structure plane, it is difficult to carry out shear test of large scale rock mass structure plane. The thesis is supported by the National Natural Science Foundation of China (No.41172243). Based on the field survey of rock mass structural plane and the high precision 3D laser scanning of the main fracture surface of rock specimen under loading and unloading test, the macroscopic and meso-fluctuation characteristics of hard contact rock mass surface are studied. Furthermore, the effects of fluctuation angle and normal stress on the shear deformation and strength of the structural plane of the perforated sawtooth rock mass and the height ratio of the step to height are studied by using the two-dimensional particle flow (PFC2D) program from a mesoscopic point of view. The empirical strength formula is applied to the calculation of slope stability by limit equilibrium method. The research results not only enrich the rock mechanics theory of shear mechanical properties and parameter values of rock mass structure plane, but also provide a useful reference for the evaluation of slope stability controlled by zigzag and step rock structural joints. The main results are as follows: (1) the surface undulation of rock structure can be divided into four types: flat, step, jagged and wavy. The roughness has self-similarity of variance. The two-dimensional roughness coefficient of structural plane can be described by the variance 蟽 2D in the vertical direction of the section of the structure surface, and the roughness fluctuation of the structural plane can be described by the variance 蟽 3D of the rough height of the whole structure surface. The distribution of the rough height of the unloading fracture surface of marble approximately accords with the distribution of Gao Si function. The skewness of the distribution of rough height is mostly less than 0, and the deflection to the right is larger. 2 the shear deformation mode of the sawtooth structural plane can be divided into climbing slope. With the increase of sawtooth fluctuation angle and normal stress, the three basic types of climbing slope gnawing and gnawing are gradually evolving from climbing and slope gnawing to gnawing mode, and this gradual change has the characteristics of near symmetric matrix distribution with the fluctuation angle and normal stress. The shear strength of the structural plane of zigzag rock mass increases nearly linearly with the increase of normal stress and fluctuation angle. An empirical formula of shear strength considering the slope climbing and gnawing effect of the zigzag structural plane is established. 3 the damage failure modes of the stepped structural plane can be divided into two types: compression shear failure and tension-shear failure, with the increase of the height ratio of the step to the ratio of H / L. In the shear process of structure plane, the ratio of bending moment to bending moment increases gradually, and the component of tensile failure increases gradually, and the deformation mode is gradually changed from compression shear failure mode to tension-shear failure mode. The structural surface first produces macroscopic crack at the corner of the step, and gradually transforms into two different damage and failure modes with the different direction of crack propagation. In view of the fact that the height and length of the step of the structural plane of rock mass is usually smaller than that of H / L (pressure-shear model), an empirical formula of shear strength considering the increase of friction angle and gnawing effect of the structural plane is established. 4 the sawtooth and step shapes will be established. The empirical formula of shear strength of structural plane is applied to the parameter selection of slope stability limit equilibrium method. Based on FLAC numerical simulation and strength reduction theory, the simulation and safety factor of slope slip failure controlled by external penetrating sawtooth type and step rock structure plane are studied, and the results of safety factor calculation by strength reduction method and limit equilibrium method are compared. The empirical formula of shear strength is proved to be correct.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU457
本文编号：2195118
[Abstract]:The hard contact rough undulating rock mass structure plane is widely developed in the hard rock mass slope / slope, and its shear mechanical properties have an important effect on the slope stability. Due to the difficulty of direct shear test and sampling of rock mass structure plane, it is difficult to carry out shear test of large scale rock mass structure plane. The thesis is supported by the National Natural Science Foundation of China (No.41172243). Based on the field survey of rock mass structural plane and the high precision 3D laser scanning of the main fracture surface of rock specimen under loading and unloading test, the macroscopic and meso-fluctuation characteristics of hard contact rock mass surface are studied. Furthermore, the effects of fluctuation angle and normal stress on the shear deformation and strength of the structural plane of the perforated sawtooth rock mass and the height ratio of the step to height are studied by using the two-dimensional particle flow (PFC2D) program from a mesoscopic point of view. The empirical strength formula is applied to the calculation of slope stability by limit equilibrium method. The research results not only enrich the rock mechanics theory of shear mechanical properties and parameter values of rock mass structure plane, but also provide a useful reference for the evaluation of slope stability controlled by zigzag and step rock structural joints. The main results are as follows: (1) the surface undulation of rock structure can be divided into four types: flat, step, jagged and wavy. The roughness has self-similarity of variance. The two-dimensional roughness coefficient of structural plane can be described by the variance 蟽 2D in the vertical direction of the section of the structure surface, and the roughness fluctuation of the structural plane can be described by the variance 蟽 3D of the rough height of the whole structure surface. The distribution of the rough height of the unloading fracture surface of marble approximately accords with the distribution of Gao Si function. The skewness of the distribution of rough height is mostly less than 0, and the deflection to the right is larger. 2 the shear deformation mode of the sawtooth structural plane can be divided into climbing slope. With the increase of sawtooth fluctuation angle and normal stress, the three basic types of climbing slope gnawing and gnawing are gradually evolving from climbing and slope gnawing to gnawing mode, and this gradual change has the characteristics of near symmetric matrix distribution with the fluctuation angle and normal stress. The shear strength of the structural plane of zigzag rock mass increases nearly linearly with the increase of normal stress and fluctuation angle. An empirical formula of shear strength considering the slope climbing and gnawing effect of the zigzag structural plane is established. 3 the damage failure modes of the stepped structural plane can be divided into two types: compression shear failure and tension-shear failure, with the increase of the height ratio of the step to the ratio of H / L. In the shear process of structure plane, the ratio of bending moment to bending moment increases gradually, and the component of tensile failure increases gradually, and the deformation mode is gradually changed from compression shear failure mode to tension-shear failure mode. The structural surface first produces macroscopic crack at the corner of the step, and gradually transforms into two different damage and failure modes with the different direction of crack propagation. In view of the fact that the height and length of the step of the structural plane of rock mass is usually smaller than that of H / L (pressure-shear model), an empirical formula of shear strength considering the increase of friction angle and gnawing effect of the structural plane is established. 4 the sawtooth and step shapes will be established. The empirical formula of shear strength of structural plane is applied to the parameter selection of slope stability limit equilibrium method. Based on FLAC numerical simulation and strength reduction theory, the simulation and safety factor of slope slip failure controlled by external penetrating sawtooth type and step rock structure plane are studied, and the results of safety factor calculation by strength reduction method and limit equilibrium method are compared. The empirical formula of shear strength is proved to be correct.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU457
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