水–岩作用下节理岩体剪切力学特性及本构模型_黄叶宁.pdf

第 42 卷 第 3 期 岩石力学与工程学报 Vol.42 No.3 2023 年 3 月 Chinese Journal of Rock Mechanics and Engineering March，2023 收稿日期：收稿日期：20220523；修回日期：修回日期：20220901 基金项目：基金项目：国家自然科学基金资助项目(U22A20600，51979218)；中国水利水电科学研究院水利部水工程建设与安全重点实验室开放研究基金项目(202001)Supported by the National Natural Science Foundation of China(Grant Nos.U22A20600 and 51979218)and Open Research Fund of Key Laboratory of Construction and Safety of Water Engineering of the Ministry of Water Resources，China Institute of Water Resources and Hydropower Research(Grant No.202001)作者简介：作者简介：黄叶宁(1993)，女，2016 年毕业于三峡大学水利水电工程专业，现为博士研究生，主要从事岩土工程方面的研究工作。E-mail：。通讯作者：邓华锋(1979)，男，博士，现任教授。E-mail： DOI：10.13722/ki.jrme.2022.0529 水岩作用下节理岩体剪切力学特性及本构模型水岩作用下节理岩体剪切力学特性及本构模型 黄叶宁1，邓华锋1，2，李建林1，冯云杰1，王文东1，齐 豫1(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.中国水利水电科学研究院 水利部水工程建设与安全重点实验室，北京 100038)摘要：摘要：在库水位周期性升降变化作用下，库岸边坡消落带节理岩体长期处于浸泡风干循环作用状态，为研究消落带节理岩体的损伤劣化特性，选取三峡库区库岸边坡消落带典型节理岩体为研究对象，进行考虑水压力升降变化和浸泡风干循环过程的水岩作用试验，系统分析节理岩体的剪切力学性能和微细观结构损伤演化规律。结果表明：(1)水岩作用下节理岩体抗剪强度呈先陡后缓的劣化趋势，总体可以分为 3 个阶段，其中前 6 个水岩作用周期导致节理面的抗剪强度参数劣化幅度占总劣化幅度的 90%左右，水岩作用 10 期后，节理面抗剪强度总劣化度为 30%左右。(2)水岩作用下节理面微细观结构损伤劣化显著，逐渐由密实状态转变为疏松多孔状态，节理面平均起伏角、平均相对起伏幅度、面积扩展率等形貌参数呈先陡后缓的劣化趋势，宏观上表现为节理面粗糙度系数 JRC 和岩壁强度降低，节理面上、下盘吻合度降低，进而导致了水岩作用下节理岩体剪切性能特性逐渐劣化。(3)基于 Clough-Duncan 双曲线模型，建立考虑水岩作用损伤的节理岩体剪切本构模型，验证分析表明，该模型可较好反映水岩作用下节理岩体剪切力学特性劣化规律。相关研究方法和结论可为库岸边坡长期变形稳定分析提供理论依据。关键词：关键词：岩石力学；水岩作用；节理岩体；剪切特性；本构模型 中图分类号：中图分类号：TU 45 文献标识码：文献标识码：A 文章编号：文章编号：10006915(2023)03054513 Shear mechanical properties and constitutive model of jointed rock mass under water-rock interaction HUANG Yening1，DENG Huafeng1，2，LI Jianlin1，FENG Yunjie1，WANG Wendong1，QI Yu1(1.Key Laboratory of Geological Hazards on Three Gorges Reservoir Area，Ministry of Education，Three Gorges University，Yichang，Hubei 443002，China；2.Key Laboratory of Construction and Safety of Water Engineering of the Ministry of Water Resources，China Institute of Water Resources and Hydropower Research，Beijing 100038，China)Abstract：Under the action of the periodic rise and fall of the reservoir water level，the jointed rock mass in the hydro-fluctuation belt of a bank slope has been in a state of soaking-air-drying cycle for a long time.In order to study the damage and deterioration characteristics of the jointed rock mass in the hydro-fluctuation belt，the typical jointed rock mass of a bank slope in the Three Gorges Reservoir area was selected as the research object.In this paper，a water-rock interaction test considering the water pressure fluctuation and soaking-air-drying cycle process is carried out，and the shear mechanical properties and the microstructure damage evolution law of the jointed rock 546 岩石力学与工程学报 2023 年 mass are systematically analyzed.The results show that：(1)the shear strength of jointed rock mass under water-rock interaction shows a deterioration trend from steep to slow，which can be divided into three stages.Among them，the degradation range of the shear strength parameters of joint surface caused by the first six water-rock interaction cycles accounts for about 90%of the total degradation range，and the total degradation degree of the shear strength of joint surfaces is about 30%after 10 water-rock interaction cycles.(2)The microstructure damage of the joint surface is significantly deteriorated under water-rock interaction.It gradually changes from a dense state to a loose and porous state.The three morphological parameters of the joint surface，such as the average fluctuation angle，the average relative fluctuation amplitude and the area expansion rate，show a trend of first steep and then slow deterioration.Macroscopically，the roughness coefficient JRC of the joint surface and the strength of the rock wall are reduced，and the coincidence degree of the upper and lower walls of the joint surface is reduced，which leads to the gradual deterioration of the shear properties of jointed rock mass under water-rock interaction.(3)Based on the Clough-Duncan hyperbolic model，a shear constitutive model of jointed rock mass considering the damage of water-rock interaction is established.The verification analysis shows that the model can better reflect the deterioration law of shear mechanical properties of jointed rock mass under water-rock interaction.The relevant research methods and conclusions can provide a theoretical basis for the long-term deformation and stability analysis of reservoir bank slope.Key words：rock mechanics；water-rock interaction；jointed rock mass；shear properties；constitutive model 1 引 言 引 言 为解决防洪、发电、供水、灌溉等问题，我国修建了数量众多的大型水库。水库蓄水后，为满足防洪发电等要求，库水位往往需要在一定范围内周期性升降，从而在两岸形成消落带。消落带成为地表水和地下水极为活跃的区域，在库水大幅度涨落条件下，消落带部分岩土体处于周期性干湿交替的状态。节理、裂隙的存在极大的影响了岩体结构的应力场和渗流场1。在库水周期性升降过程中，水分子沿节理、裂隙入渗和出渗，与节理岩体发生一系列物理、化学作用，逐渐改变岩体的微观结构和矿物成分，促进原有节理、裂隙的扩展、发育和新生节理、裂隙的产生，进而导致库岸边坡消落带岩体物理力学特性劣化，直接影响库岸边坡的变形和稳定。三峡库区典型岸坡消落带照片如图 1 所示，三峡工程 175 m蓄水运行十余年来，175 m高程水位线已成为节理裂隙发育的分界线，说明消落带岩体的损伤劣化与库水位周期性升降变化密切相关。消落带是岸坡变形稳定的敏感地带，黄波林等2也提出消落带岩体的劣化很可能将三峡库区地质灾害带入新的发展阶段。近年来，水岩作用导致的消落带岩体物理力学特性劣化逐渐受到相关领域学者的关注，并针对岸坡消落带开展了较多的水岩作用研究，其中消 图 1 典型库岸边坡消落带岩体损伤劣化图 F