摘要
泥岩具有强度低、遇水易软化的特点,尤其是富水泥岩地层,对工程岩体的长期稳定性影响较大,但相关研究少有报道,因此亟待深入研究泥岩遇水蠕变特性。开展了不同初始含水率泥岩试样在天然和浸水条件下的分级加载蠕变试验,研究了水对岩体蠕变特性的影响机理,结合广义Kelvin模型,构建了考虑含水劣化效应的蠕变损伤本构模型,并将新模型嵌入FLAC3D有限差分软件中,模拟了不同工况下泥岩蠕变变形特性,并与室内试验结果进行了对比。结果表明:随着含水率的增大,岩体蠕变应变量增大,长期强度降低;相比天然条件,浸水环境使得岩体长期强度劣化更为严重,试样初始含水率越小,浸水条件对其蠕变变形影响越大;将岩体因水的劣化效应定义为蠕变参数的损伤因子,损伤因子随着含水率的增加而提高;考虑含水劣化效应的蠕变损伤本构模型数值模拟结果与室内试验结果基本吻合,验证了新模型的合理性。
Mudstone has the characteristics of low strength and easy water softening,which has great influence on the long-term stability of engineering rock mass,especially in the water-rich mudstone strata.Few corresponding studies have been reported.Therefore,it is urgent to further study the creep characteristics of mudstone with water.In this paper,stepwise loading creep tests of mudstone samples with different initial water content under natural and water immersion conditions were conducted to study the influence mechanism of water on the creep characteristics of rock mass.Combined with the generalized Kelvin model,a creep damage evolution model considering the deterioration effect of water content was established.The new model was embedded in FLAC^(3D)finite different code to realize the programming of the model.By comparing with the numerical creep deformation of mudstone under different conditions and the experimental results.The research shows that with the increase of water content,the creep strain of rock mass increases and the long-term strength decreases.Compared with that in natural condition,the long-term strength deterioration of soft rock becomes more serious in water immersion condition.In addition,the larger the initial water content,the smaller the influence of immersion conditions on it creep deformation.The deterioration effect of rock mass due to water is defined as the damage factor of creep parameters.The damage factor increases with the increase of water content.The numerical simulation results of the creep damage constitutive model considering water degradation are basically consistent with the indoor test results,which verifies the rationality of the new model.
作者
王先甲
高增奎
付志强
张奥
张国华
WANG Xianjia;GAO Zengkui;FU Zhiqiang;ZHANG Ao;ZHANG Guohua(China Railway Seventh Bureau Group Wuhan Engineering Co.,Ltd.,Wuhan 430200,China;Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan 430074,China)
出处
《安全与环境工程》
CAS
CSCD
北大核心
2024年第5期28-37,共10页
Safety and Environmental Engineering
基金
国家自然科学基金项目(42277173、52209148)。
关键词
泥岩
蠕变特性
浸水条件
蠕变试验
含水劣化效应
蠕变损伤本构模型
mudstone
creep characteristics
immersed condition
creep experiment
water deterioration effect
creep damage constitutive model
