基于傅里叶近似法的S-RM细观损伤过程研究  

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

作　　者：章涵 胡新丽[1] 吴爽爽 ZHANG Han;HU Xin-li;WU Shuang-shuang(Faculty of Engineering, China University of Geosciences (Wuhan), Wuhan 430074, China)

机构地区：[1]中国地质大学(武汉)工程学院

出　　处：《浙江大学学报（工学版）》2019年第10期1955-1965,共11页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(41630643)

摘　　要：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.The numerical tests of soil-rock mixture(S-RM) were performed based on the in-suit horizontal pushshear test(HPST) in order to clarify the meso-damage evolution of S-RM. The mechanical properties and the mesodamage 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 in0°-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 roundblocks 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°.

关 键 词：土石混合体(S-RM) 傅里叶近似法 水平推剪试验 离散元方法 微裂纹 细观损伤演化过程 

分 类 号：TU413[建筑科学—岩土工程]