考虑衰减滞后的均质土坡双剪切带破坏模式研究  

Failure Mode of Double Shear Band on Attenuation Hysteresis of Delamination Strength Reduction Effect

作　　者：侯世伟[1] 焦宏宇 杜修力[2] 张皓[1] HOU Shiwei;JIAO Hongyu;DU Xiuli;ZHANG Hao(School of Civil Engineering,Shenyang Jianzhu University,Shenyang 110168,China;Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]沈阳建筑大学土木工程学院,沈阳110168 [2]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124

出　　处：《北京工业大学学报》2024年第12期1437-1447,共11页Journal of Beijing University of Technology

基　　金：国家重点研发计划资助项目(2018YFD1100404);北京工业大学教育部重点实验室资助项目(2022B08);沈阳市中青年科技创新人才支持计划资助项目(RC220171)。

摘　　要：为了研究不同侵蚀条件下均质土坡双剪切带破坏模式的启动和形成机理,提出改进分层折减原理,引入综合折减系数(comprehensive reduction factor,CRF)和衰减滞后比(attenuation hysteresis ratio,AHR),获得基于分层折减原理的典型双剪切带破坏模式及剪应变演化规律,分析不同AHR条件下剪应变峰值及其位置,得到双带出现与双带稳定时的衰减扩散比(attenuation spread ratio,ASR)阈值条件,并与CRF曲线特征点对比,讨论将CRF作为双带特征判定指标的合理性。研究表明:典型双剪切带剪应变演化分为3个阶段,分别为向坡面方向积累、向坡面方向分裂并迅速扩展、向坡内侧迅速扩展。最终形成的剪切带范围由双带及其裹挟的滑带土体构成。随着AHR增长,剪应变峰值向坡面移动,第1峰值剪应变减小,第2峰值剪应变增加,峰值点剪应变总和不变,峰值点位最终趋于稳定。根据ASR阈值条件将不同AHR的边坡失稳过程分为单剪切带向坡面移动、双剪切带向坡面移动和双剪切带位置稳定3个区间,并验证了CRF判定条件的合理性。To study the initiation and formation mechanism of the failure mode of homogeneous soil slopes with double shear bands under different erosion conditions,an improved layered reduction principle was proposed in this paper.The comprehensive reduction factor(CRF)and attenuation hysteresis ratio(AHR)were introduced.The typical failure mode of double shear bands based on the layered reduction principle and the evolution law of shear strain were obtained.Afterwards,the position and size of the shear strain peak at different AHR were analyzed,and the threshold conditions for the attenuation spread ratio(ASR)when double bands emerge and stabilize were obtained.A comparison has been made between the ASR values at the intersection points and stable points of the cumulative release fraction(CRF)curves.The rationality of using CRF as the criterion for determining the emergence and stabilization of double bands was discussed.The research shows that the evolution of shear strain of typical double shear band can be divided into three stages,namely,accumulation towards slope,splitting and rapid expansion towards slope,and rapid expansion at the inner side of slope.With the increase of AHR,the peak shear strain moves to the slope and tends to be stable.In the moving stage,the peak value 1 decreases and the peak value 2 increases,while the total peak shear strain does not change.According to ASR threshold conditions,the slope instability process of different AHR can be divided into three sections:single shear zone moving to the slope,double shear zone moving to the slope and double shear zone stable position,and the rationality of CRF criterion condition is verified.

关 键 词：分层折减原理 衰减滞后 双剪切带 渐进破坏 土坡 降雨入渗 

分 类 号：TU44[建筑科学—岩土工程]