基于改进西原模型的不同含水率砂岩蠕变实验及理论研究  

Experimental and theoretical study on creep behaviors of sandstone with different moisture contents based on modified Nishihara model

作　　者：孙晓明[1,2] 缪澄宇 姜铭 张勇[1,2] 杨柳[1,2] 郭波[1,2] SUN Xiaoming;MIAO Chengyu;JIANG Ming;ZHANG Yong;YANG Liu;GUO Bo(State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)深部岩土力学与地下工程国家重点实验室,北京100083 [2]中国矿业大学(北京)力学与建筑工程学院,北京100083

出　　处：《岩石力学与工程学报》2021年第12期2411-2420,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51874311,51904306);中央高校基本科研业务(2021YJSSB05)。

摘　　要：为研究深部巷道围岩在地下水作用下的长时强度变化对围岩稳定性的影响,以万福煤矿深部巷道围岩为主要研究对象,对不同含水率状态下的砂岩样品进行单轴压缩实验及单轴蠕变实验。发现含水率对岩石强度及蠕变长时强度存在明显的软化效应;根据等时蠕变曲线黏弹性应变规律,提出黏性模量E_(v),获得其与弹性模量均随含水率的增加呈非线性软化的规律;此外,基于一种新的能够描述加速蠕变行为的黏壶元件,结合实验结果运用损伤理论提出改进的西原模型。运用该模型对蠕变实验结果进行参数辨识并与实验曲线进行对比分析,获得较好的结果,表明此模型能够较好地描述蠕变各阶段的力学行为;同时发现损伤蠕变模型参数E_(0)′,E_(1)′,η_(1)′在相同应力条件下差距不大,且各参数受蠕变应力σ影响存在一定规律,E0′与σ成线性关系,E_(1)′,η_(1)′与σ成负指数关系。因此可以根据现场含水率及不同应力水平对岩石所处蠕变状态进行合理分析,结合新的蠕变长时强度判别方法,对巷道长期稳定使用及巷道蠕变破坏的提前预报提供依据,具有重要的现实意义。In order to study the influence of the long-term strength change on the stability of the surrounding rock in deep roadways under the action of groundwater.The sandstone in Wanfu Coal Mine was taken as the main research object,and uniaxial compression test and uniaxial creep test were carried out with different moisture contents.It is found that the water content has an obvious softening effect on the rock strength and long-term strength.According to the viscoelastic strain law of isochronal creep curve,a viscoelastic modulus E_(v) was proposed,and the nonlinear softening laws of the viscoelastic modulus and the elastic modulus with the water content were obtained.A new nonlinear viscous dashpot element that can describe the accelerated creep behavior was proposed,by which an improved Nishihara model was developed based on the combination of the damage theory and the experimental results.The model was used to identify the parameters of the creep experiment results,and it is shown that the model has a good fitting effect on the experimental results,which means the model can better describe the mechanical behavior of each stage of creep.At the same time,it is found that the damage creep model parameters E_(0)′,E_(1)′,η_(1)′have little difference under the same stress,and each parameter is affected by the creep stress.Specifically,E_(0)′has a linear relationship with σ,while E_(1)′and η_(1)′have a negative exponential relationship with σ.Therefore,the creep state of rock can be reasonably analyzed according to the moisture content and different stress levels.Combined with the new long-term creep strength discrimination method,the developed model can provide a basis for the long-term stable use of roadways and the advance prediction of creep failure of roadways.

关 键 词：岩石力学 岩石蠕变 吸水损伤 加速蠕变 西原模型 

分 类 号：TU45[建筑科学—岩土工程]