库岸危岩剪切带-基岩界面宏细观剪切贯通机制及力学特性研究
Study on macro-meso shear transfixion mechanisms and mechanical properties of shear band-bedrock interfaces of dangerous rock on reservoir bank
刘新荣 1郭雪岩 1周小涵 1罗新飏 1王浩 1李沛瑶 1周福川2
作者信息
- 1. 重庆大学土木工程学院,重庆 400045;重庆大学库区环境地质灾害防治国家地方联合工程研究中心,重庆 400045;重庆大学山地城镇建设与新技术教育部重点实验室,重庆 400045
- 2. 重庆大学土木工程学院,重庆 400045;重庆工程职业技术学院,重庆 402260
- 折叠
摘要
以三峡库区"板壁岩"危岩为研究背景,在总结岸坡危岩内部剪切带形成过程及基本特征的基础上,通过室内剪切试验和数值模拟手段,从宏细观的角度研究该岸坡危岩内部剪切带-基岩界面的剪切贯通机制及其力学特性.研究表明:(1)剪切带为危岩体失稳的主控因素,内部充填物质具有层状无胶结特征;(2)在常法向应力作用下,界面的破坏模式可以总结为台阶根部张裂-台阶爬坡,岩板损伤-台阶剪断,岩板裂纹贯通-台阶剪碎;(3)界面剪切应力-剪切位移曲线分为压密阶段、近加载端台阶根部斜裂缝出现阶段、近似弹性变形及微裂隙扩展阶段、近加载端台阶剪断阶段、剩余台阶剪断阶段及残余阶段6个阶段;(4)界面的峰值剪切强度和残余强度随法向应力、层厚和台阶高度的增加而增加,竖向累积位移随法向应力的增加而减小、随层厚和台阶高度的增加而增加;(5)界面裂纹数量变化曲线呈"S"型,共经历裂纹缓慢增加(岩板表面磨损)-裂纹迅速扩展(台阶剪断)-裂纹数量稳定(残余摩擦)3个发展阶段,试样内部颗粒应变能和胶结应变能变化趋势与剪切应力-剪切位移曲线变化相近,总能量、摩擦能及阻尼能随剪切位移的增加而增加.研究成果对剪切带整体力学性质及含剪切带危岩稳定性的研究具有借鉴意义.
Abstract
Taking Banbiyan dangerous rock in the Three Gorges Reservoir Area as a research object,the formation process and characteristics of the shear band in the dangerous rock were summarized.In this paper,laboratory tests and numerical simulation were used to study the shear transfixion mechanism and mechanical properties of the shear band-bedrock interface from a macro-meso perspective.The results show that:(1)the shear band is the main controlling factor of the dangerous rock instability,and the internal filling material is laminar and unbonded.(2)Under the condition of constant normal stress,the failure modes of the interface can be summarized as step root tensile fracture-step climbing,rock slab damage-step shear fracture,rock slab crack coalescence-step shear broken.(3)Six typical stages can be observed in shear stress-shear displacement curves,including the compaction stage,the oblique crack occurring stage at the step root near the loading end,the approximate elastic deformation and micro-crack propagation stage,the step near the loading end shear fracture stage,the remaining steps shear fracture stage,and the residual stage.(4)The peak shear strength and the residual strength of the interface increase with the increase in normal stress,layer thickness and step height.The vertical cumulative displacement decreases with the increase in normal stress and increases with the increase in layer thickness and step height.(5)The interface crack number curve shape is"S"type,which can be divided into three stages,including the crack number slowly increasing stage(rock slab surface wear),the rapid crack propagation stage(steps shear fracture),and the crack number keeping stable stage(residual friction).The curve change trend of particle strain energy and cementation strain energy is similar to that of the shear stress-shear displacement curve,and the total energy,friction energy,and damping energy increase with the increase in shear displacement.The research results are of reference significance to the study of the mechanical properties of the shear band and the stability of the dangerous rock.
关键词
岩石力学/三峡库区/危岩/剪切带-基岩界面/剪切力学特性/数值模拟Key words
rock mechanics/the Three Gorges Reservoir/dangerous rock/shear band-bedrock interface/shear mechanical properties/numerical simulation引用本文复制引用
出版年
2024
NETL
NSTL
万方数据