水库蓄水土质岸坡拉剪断裂破坏机制研究  

Study on Tensile and Shear Failure Mechanism of Soil Bank Slope under Reservoir Filling

作　　者：周云涛[1] 唐红梅[1] 陈洪凯[1] 

机构地区：[1]重庆交通大学岩土工程研究所,重庆400074

出　　处：《重庆师范大学学报（自然科学版）》2015年第5期48-54,共7页Journal of Chongqing Normal University:Natural Science

基　　金：国家自然科学基金(No.51378521);重庆市自然科学基金重点项目(No.cstc2013jjB005)

摘　　要：基于土体结构特征从土体宏微观变化、岸坡变形、掏空等方面解释了水库蓄水期间土体浸泡软化机制。采用断裂力学方法推导求证了土质岸坡浸泡软化拉剪断裂破坏机制,并将土质岸坡浸泡软化拉剪断裂破坏进一步分为基座软化拉剪破坏模式和基座掏空拉剪破坏模式,给出了两种破坏模式的地貌演绎过程。通过建立两种破坏模式的物理模型和力学模型,从断裂力学角度推导出了潜在坍塌体裂缝尖端应力强度因子表达式。算例分析表明,土质岸坡破坏表现为显著的浸泡拉剪断裂破坏模式,并讨论了潜在坍塌体长度、高度、裂缝角度以及裂缝垂直长度对应力强度因子的影响。土体断裂韧度较小,导致岸坡坍塌体规模不大,土质岸坡的浸泡软化整体滑移破坏往往是滞后的,通常岸坡先局部软化,基座变形后发生塌岸破坏,后续上覆岸坡失去支撑发生整体式滑移。Based on the structural feature of soil this paper explained soaking softening mechanism through some aspects, such asmacro-microcosmic changes of soil, deformation or emptying of bank slope under reservoir filling. By using fracture mechanicsmethod, tensile and shear fracture failure mechanism caused by soaking and softening for soil bank slope was deduced and proved,furthermore, tensile and shear fracture failure caused by soaking and softening was divided into two types, i. e. , tensile and shearfailure model with foundation bed soften and tensile and shear failure model with foundation emptying, meanwhile, deductiveprocess of two types of failure models were given. By means of established physics model and mechanics model for two types of fail-ure models, stress intensity factor of crack tip for potential collapse mass was deduced from the angle of fracture mechanism. Caseanalysis indicated that failure of soil bank slope manifested as tensile and shear fracture failure model caused by soaking, and thispage respectively discussed the effects on stress intensity factor caused by length, height, angle of crack and perpendicular length ofcrack. Small fracture toughness of soil was the cause of less collapse scale of bank slope. The occurrence of overall slippage failure ofsoaking and softening of soil bank slope was frequently hysteretic; in general, firstly, the bank slope was softened partly, then bankslump took place after foundation bed deformed, finally, overlying overall slippage failure of bank slope occurred without supporting.

关 键 词：浸泡软化机制 拉剪断裂破坏机制 断裂力学 土质岸坡 三峡库区 

分 类 号：P694[天文地球—地质学]