基于傅里叶近似法的S-RM细观损伤过程研究

为了明确土石混合体（S-RM）的细观损伤演化过程，基于现场水平推剪试验，采用离散元数值模拟方法，开展S-RM水平推剪数值实验研究，分析S-RM的力学特性和细观损伤演化特征. 基于傅里叶近似法，提出微裂纹各向异性定量评价方法. 根据S-RM变形破坏过程中微裂纹各向异性演化特征，划分了S-RM水平推剪细观损伤阶段，通过分析各细观损伤阶段的裂纹扩展特征及发展规律，揭示了S-RM剪切滑动面形成机理. 试验结果表明，微裂纹各向异性程度随着剪切位移的增加而增强，当主裂纹形成后不再有明显变化，微裂纹主要分布在0°~45°与135°~180°；微裂纹的产生主要由于颗粒间的拉应力导致，拉裂纹的各向异性程度明显大于剪切裂纹；土体中微裂纹的贯通导致多条宏观裂纹的形成，由于块石的翻转宏观裂纹逐渐扩展形成一条绕石宏观主裂纹，S-RM沿着主裂纹滑移形成绕石剪切滑动面；滑动面的倾角为34°，与主裂纹倾角和微裂纹在0°~90°的平均角度一致.

Damage evolution of soil-rock mixture based on Fourier series approximations method

The numerical tests of soil-rock mixture (S-RM) were performed based on the in-suit horizontal push-shear test (HPST) in order to clarify the meso-damage evolution of S-RM. The mechanical properties and the meso-damage evolution characteristics of S-RM were analyzed by using discrete element method. A quantitative evaluation method for evaluating the anisotropy of S-RM meso-cracks was proposed based on the Fourier series approximation method. The meso-damage stages of HPST of S-RM were divided based on the anisotropy evolution of meso-cracks in the process of deformation and destruction of S-RM. The formation mechanism of S-RM shear surface was analyzed by analyzing the growth and evolution of cracks in different meso-damage stages. Results showed that the anisotropy degree of meso-cracks increased with the increment of shear displacement, but it has no obvious change any more after the formation of principal crack. The dips of meso-cracks were mainly distributed in 0°-45° and 135°-180°. The generation of meso-cracks was mainly caused by the tensile stress between particles. The anisotropy degree of tensile meso-cracks was larger than that of shear meso-cracks. The connections of meso-cracks in the soil gave rise to the formation of multiple macro-cracks. The macro-cracks developed and formed a round-blocks principal crack because of the rotation of rock blocks. The S-RM slide along the principal cracked to form a round-blocks shear slide surface. The dip of slide surface was 34°, same as the dip of principal crack and the average dip of meso-cracks in the range of 0°-90°.