基于平行黏结模型的水-岩作用下砂岩蠕变模拟及损伤机制研究  

Creep simulation and deterioration mechanism of sandstone under water-rock interaction based on parallel bond model

作　　者：骆祚森 朱作祥 苏卿[3] 李建林[1,2] 邓华锋[1,2] 杨超[1,2] LUO Zuo-sen;ZHU Zuo-xiang;SU Qing;LI Jian-lin;DENG Hua-feng;YANG Chao(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area of Ministry of Education,China Three Gorges University,Yichang,Hubei 443002,China;College of Civil Engineering&Architecture,China Three Gorges University,Yichang,Hubei 443002,China;College of Intelligent Construction,Wuchang University of Technology,Wuhan,Hubei 430223,China)

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,湖北宜昌443002 [2]三峡大学土木与建筑学院,湖北宜昌443002 [3]武昌理工学院智能建造学院,湖北武汉430223

出　　处：《岩土力学》2023年第8期2445-2457,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金联合基金重点项目(No.U2034203);湖北省自然科学基金青年项目(No.2021CFB191);宜昌市自然科学研究项目(No.A21-3-005)。

摘　　要：为探明库水位周期性升降作用下消落带岩体蠕变损伤机制,基于PFC中的平行黏结模型(parallel bond model,PBM),考虑水-岩作用对黏结的弱化和材料特性随时间的变化,提出水-岩作用下砂岩蠕变的离散元模拟方法,并在室内试验基础上开展水-岩作用下砂岩蠕变模拟。研究结果表明:在破坏应力水平下,试样微裂纹扩展与蠕变应变规律相似,可分为衰减扩展阶段、稳定扩展阶段、加速扩展阶段,且随水-岩作用周期增加,加速扩展阶段的耗时占总耗时的比例增大;试样蠕变破坏时,随水-岩作用周期增加,剪切裂纹占比逐渐增加,微裂纹倾角分布逐渐分散,倾角分布在65°和115°附近的微裂纹逐渐增加,试样的张性破坏减弱,剪性破坏增强;水-岩作用下,试样能储存的最大胶结能不断降低,且储存相同胶结能时对应的应变不断增大,与实际岸坡在水-岩作用下岩体整体承载能力降低、变形增大的规律一致。提出的水-岩作用下砂岩蠕变模拟方法具有较好的可行性,为库岸边坡岩石在库水位升降影响下的模型研究提供理论基础。To clarify the creep damage mechanism of rock mass under the periodic variation of reservoir water level in the hydro-fluctuation belt,by considering the weakening effect of the water-rock interaction on the bond and the variation of material properties with time,we proposed a new discrete element method based on the parallel bond model in particle flow code(PFC)and implemented the creep simulation of water-rock interaction based on laboratory tests.The results indicate that under the failure stress level,the micro-crack growth behavior of the samples is similar to the creep strain and it consists of three stages:attenuation growth stage,stable growth stage,and accelerated growth stage.The ratio of the accelerated growth stage’s time to the total time of the micro-crack growth process increases with the period of the water-rock interaction.When the sandstone is damaged in the creep process,the proportion of shear cracks gradually increases with the period of the water-rock interaction and the distribution of inclination angles of micro-crack gradually scatters.The micro-cracks in the areas near the inclination angles of 65°and 115°increase,the tensile strength of the samples weakens and the shear strength increases.Under the water-rock interaction,the maximum cementation energy stored in the samples decreases and the strain with the same cementation energy stored in the samples increases,which is consistent with the rules observed in the field that the overall bearing capacity of the rock mass decreases and the deformation of rock mass increases.Because the method is feasible to simulate sandstone creep process under water-rock interaction,the study can provide theoretical support for the model study of reservoir bank slope rocks under the influence of reservoir water level fluctuation.

关 键 词：岩石力学 水-岩作用 蠕变试验 离散元法 细观参数劣化 

分 类 号：TU451[建筑科学—岩土工程]