水压循环作用下砂岩损伤本构模型研究  

Study on damage constitutive model of sandstone under hydro-pressure cycle effect

作　　者：赵二平[1] 贾小兵 龚章龙[3] 李建林 ZHAO Erping;JIA Xiaobing;GONG Zhanglong;LI Jianlin(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University, Yichang 443002,Hubei,China;Three Gorges Vocational College of Electric Power,Yichang 443000,Hubei,China;China Gezhouba Group Sixth Engineering Co.,Ltd.,Kunming 650000,Yunnan,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]三峡电力职业学院,湖北宜昌443000 [3]中国葛洲坝集团第六工程有限公司,云南昆明650000

出　　处：《水利水电技术》2018年第9期1-7,共7页Water Resources and Hydropower Engineering

基　　金：国家重点研发计划项目(2016YFC0400200);国家自然科学基金面上项目(51279091);三峡库区地质灾害教育部重点实验室开放基金(2015KDZ17)

摘　　要：针对三峡库区水位反复升降作用下岩体质量劣化易致边坡及地基失稳的问题,以三峡库区典型砂岩为研究对象,利用岩石全自动多功能三轴流变仪开展了不同水压循环作用次数下砂岩力学特性试验研究。结果表明:水压循环次数越多对砂岩试样造成的损伤越大;根据水压循环过程中岩体的应力应变关系曲线特征,借助损伤理论及Weibull概率密度函数,建立了考虑砂岩损伤效应的损伤统计本构模型。对比分析表明:该模型与试验曲线符合较好,能够较好的反映水压循环作用对砂岩的损伤效应;随着水压循环作用次数的增加,Weibull分布参数F和m均逐渐减小; F与围压之间呈指数关系,而m与围压之间呈负指数关系,揭示了水压循环作用下岩样宏观强度逐渐降低的特性。研究成果对库区边坡及地基在水压循环作用下的稳定分析具有一定的参考价值。Aiming at the problem of that the quality deterioration of rock mass is prone to cause the instabilities of slope and foundation under the effect of the repeated fluctuations of the water level within area of the Three Gorges Reservoir,the experimental study on the mechanical performance of sandstone under the effects from various numbers of hydro-pressure cycles is made with full-automatic and multipurpose rock triaxial rheological apparatus by taking the typical sandstone in the area of the Three Gorges Reservoir.The result shows that the more the numbers of hydro-pressure cycle are,the larger the damage to the sandstone sample is to be.In accordance with the characteristics of stress-strain curve of the rock mass during the hydro-pressure cycle,the statistical damage constitutive model with the consideration of the damage effect of the sandstone is established by means of the relevant damage theory and Weibull probability density function.The comparative analysis indicates that the model is better coincided with the experiment curve,and then can better reflect the effect from the hydro-pressure cycle on the damage of the sand stone.Following with the increase of the numbers of the hydro-pressure cycle,both Weibull distribution parameters--F and m are gradually decreased.F exhibits an exponential relationship with confining pressure,while a negative exponential relationship is there between m and confining pressure,which reveals the behavior of the gradual decrease of the macroscopic strength of the rock sample.The study result has a certain referential value for the stability analysis made on the slope and foundation under hydro-pressure cycle in reservoir area.

关 键 词：砂岩 水压循环 损伤演化方程 损伤本构方程 岩石材料损伤 广义胡克定律 三轴压缩试验 抗压强度 

分 类 号：TU452[建筑科学—岩土工程]