土石混合体-基岩界面剪切力学特性块石尺寸效应  

Influence of the block stone size on shear mechanical behavior of soil-rock mixture-bedrock interface

作　　者：杨忠平[1,2,3] 李进 刘浩宇[1,2,3] 张益铭 刘新荣[1,2,3] YANG Zhong-ping;LI Jin;LIU Hao-yu;ZHANG Yi-ming;LIU Xin-rong(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area of Ministry of Education,Chongqing University,Chongqing 400045,China;National Joint Engineering Research Center for Prevention and Control of Environmental Geological Hazards in the TGR Area(Chongqing),Chongqing University,Chongqing 400045,China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]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 [3]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),重庆400045

出　　处：《岩土力学》2023年第4期965-974,共10页Rock and Soil Mechanics

基　　金：重庆市自然科学基金面上项目(No.cstc2021jcyj-msxm X0558);国家重点研发计划项目(No.2021YFB3901402)。

摘　　要：土石混合体-基岩界面的抗剪强度是控制坡体稳定性的重要参数之一,是工程设计的重要参数。为探究块石尺寸对土石混合体-基岩界面剪切力学特性的影响,开展了含不同块石尺寸的土石混合体-基岩界面室内大型剪切试验。结果表明:接触界面的破坏模式受块石尺寸和法向压力的影响不显著,均表现为应变硬化特征;法向压力会削弱块石尺寸效应的影响;随块石尺寸增加,抗剪强度和抗剪强度指标(φ、c)先增加后减少,既存在着正尺寸效应,又存在着负尺寸效应,尺寸效应对内摩擦角φ的影响有限,整体在29°波动,而对表观黏聚力c影响较大;不同块石尺寸试样在不同法向压力作用下均表现出了明显的剪缩行为,法向压力能够增强土石混合体的剪缩特性;土石混合体-基岩界面为薄弱的潜在滑移面,随着块石尺寸系数的增加,薄弱破坏面有向土石混合体内部转化的趋势。The shear strength of the soil-rock mixture-bedrock interface is a key parameter for the stability of the slope and engineering design. In order to explore the influence of the block stone size on the shear mechanical behavior of the soil-rock mixture-bedrock interface, a series of large-scale laboratory shear tests of the soil-rock mixture-bedrock interface with different block stone sizes was carried out. The results show that the failure mode of the contact interface is not significantly affected by the size of the block stone and the normal pressure, and both are characterized by strain hardening. However, the normal pressure will weaken the impact of the block stone size effect. As the size of the block stone increases, the shear strength and the shear strength index(φ, c)first increased and then decreased. There are both a positive size effect and a negative size effect. The size effect has a limited influence on the angle of internal friction φ, which fluctuates around 29°. However, the size effect has a significant influence on the apparent cohesion c. The specimens with different block sizes show obvious shear contraction behavior under different normal pressures, and the normal pressure can enhance the shear contraction characteristics of the soil-rock mixture. The soil-rock mixture-bedrock interface is a weak potential slip surface. With the increase of the block size coefficient, the weak failure surface tends to transform into the soil-rock mixture.

关 键 词：接触界面 尺寸效应 土石混合体 剪切力学特性 

分 类 号：TU452[建筑科学—岩土工程]