摘要
受流变特性的影响,岩体的力学参数具有时效性。为得到边坡时效安全系数,在FLAC数值模拟软件中,通过对岩体抗剪强度参数先折减再流变、先流变再折减及强度参数随流变时步折减(老化理论)3种方式将流变分析与强度折减法相结合,实现了理想弹塑性与黏弹塑性分析的有机结合。研究了时效安全系数的物理意义,利用边坡特征点水平位移增量量化表征了岩体流变特性对稳定性的影响程度;采用岩体强度参数的初始瞬时值和长期强度值,计算得到了考虑边坡时效性安全系数的上下限值。结合黄山石灰石矿山工程实例分析得到:采用抗剪强度参数长期值和瞬时值进行流变分析的结果与现场实际监测数据误差较大,强度参数随流变时间折减时最大误差为5.03%,拟合度最高,模拟结果最接近工程实测分析,能够为边坡长期稳定性评价及滑坡预警预测提供理论依据;将边坡设计的永久性过渡到时效性,流变计算5 a,边坡的安全系数由1.35降低至1.25,表明未来5年边坡处于稳定状态。
The stability of a slope is affected by the rheological properties of the rock mass.The finite difference strength reduction method based on ideal elastic-plastic analysis can be used to directly calculate the safety coefficient of a slope,but the calculated safety coefficient is the theoretical instantaneous value independent of time.To represent the timeliness of slope safety factor,in FLACnumerical simulation software,the Cvisc(Composite viscoelastoplastic)model is used to combine the strength reduction method with rheological calculation in the following three ways.Firstly,the strength reduction method is used for calculation and then the rheological analysis is carried out.Secondly,the rheological analysis is carried out first and then the strength reduction method is used to calculate the safety factor.Thirdly,the strength parameters are compiled as a function of time according to the aging theory and then coupled with the rheological time step.In the analysis of slope stability,the ideal elastic-plastic analysis and visco-elastic-plastic analysis are combined.The physical significance of calculating the safety factor with each reduction method is discussed.The upper and lower limits of the slope safety factor considering the timeliness are obtained.Taking the Huangshan Limestone Mine with a large slope as an example,in the rheological analysis,the results calculated with the long-term and instantaneous values of the rock mass shear strength parameters show large errors compared with the monitored data in the field.The maximum error is 5.03%when the shear strength parameter decreases with the rheological time.The results obtained by this method have the highest goodness of fit with the actual monitored data in the field,indicating that the safety factor and the horizontal displacement-time curve calculated by this method are the closest to the measured results.The calculated results can provide the theoretical basis for slope long-term stability evaluation and landslide early warning and prediction.In the r
作者
崔阿能
胡斌
崔凯
刘杨
李京
CUI A-neng;HU Bin;CUI Kai;LIU Yang;LI Jing(School of Resources and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China;Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources,Wuhan 430081,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2022年第4期1837-1844,共8页
Journal of Safety and Environment
基金
国家自然科学基金项目(U1802243,41672317)
湖北省技术创新专项(重大项目)(2017ACA184)
武汉科技大学重大科技项目培育类创新团队项目(A类)(2018TDX01)。
关键词
安全工程
强度折减法
折减过程
流变
数值模拟
safety engineering
strength reduction method
reduction process
rheology
numerical modeling
