摘要
土石混合体与基岩接触界面是高填方体边坡和天然斜坡失稳不容忽视的潜在滑移面。通过室内大型直剪试验和离散元数值模拟探究了含石率对土石混合体—基岩界面剪切力学特性的影响及接触面剪切破坏机理。结果表明:土石混合体—基岩界面的剪应力-剪切位移曲线随法向压力的增大有由应变软化向应变硬化转变的趋势;剪应力-剪切位移曲线出现“V型跳跃”主要与颗粒破碎、转动和翻越有关;土石混合体—基岩界面抗剪强度和抗剪强度指标随含石率的增加先增大后减小,存在着最优含石率,但内摩擦角φ变化不大,在38°左右波动;剪切带的分布和形态受含石率和法向压力影响显著,法向压力和含石率越高,剪切带就越厚;剪切带内的块石破坏表现为表面研磨、局部破碎和完全破碎3种模式;法向压力和含石率都是影响相对破碎率Br的主要原因,表现为随着含石率和法向压力的增加,块石相对破碎率不断增加。
The contact interface between the soil-rock mixture and the bedrock is often a potential slip surface that cannot be ignored for the instability of highly-filled slopes and natural slopes.Through the large-scale direct shear tests in the laboratory and the numerical simulations using the discrete element software,the influences of stone content on the shear mechanical properties of the soil-rock mixture-bedrock interface and the shear failure mechanism of the contact surface are investigated.The results show that the shear stress-shear displacement curve of the soil-rock mixture-bedrock interface changes from strain softening to strain hardening with the increase of normal pressure.The"V-shaped jump"in the shear stress-shear displacement curve is mainly related to particle breakage,rotation and overturning.The shear strength and shear strength indexes of the soil-rock mixture-bedrock interface increase first and then decrease with the increase of rock content,and there is an optimal stone content to maximize the shear strength,but the internal friction angle φ does not change significantly and fluctuates around 38°.The distribution and morphology of the shear zone are significantly affected by the stone content and normal pressure.The higher the normal pressure and rock content,the thicker the shear zone.The failure of the block stones in the shear band can be divided into three modes:surface grinding,partial crushing and complete crushing.The normal pressure and stone content are the reasons that affect the relative crushing rate Br.The specific performance is that with the increase of the stone content and normal pressure,the relative crushing rate of block stones increases continuously.
作者
杨忠平
李进
蒋源文
胡元鑫
赵亚龙
YANG Zhong-ping;LI Jin;JIANG Yuan-wen;HU Yuan-xin;ZHAO Ya-long(School of Civil Engineering,Chongqing University,Chongqing 400045,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400045,China;National Joint Engineering Research Center for Prevention and Control of Environmental Geological Hazards in the TGR Area,Chongqing University,Chongqing 400045,China;Headquarters of Chongqing Yuwu Airport,Chongqing 401120,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2021年第8期1443-1452,I0005,共11页
Chinese Journal of Geotechnical Engineering
基金
国家重点研发计划项目(2018YFC1504802)
国家自然科学基金项目(41772306)
中央高校基本科研业务费项目(2019CDXYTM0032)。
关键词
土石混合体
含石率
基岩界面
剪切特性
soil-rock mixture
stone content
bedrock interface
shear characteristic
