黏土岩中水泥锚固体滑脱的有限-离散元模型初探  

Finite-discrete element model for slip debonding of cement anchors in clay rock

作　　者：程树范 曾亚武[1] 高睿[1,2] 张嘉凡 覃祥瑞[4] CHENG Shufan;ZENG Yawu;GAO Rui;ZHANG Jiafan;QIN Xiangrui(School of Civil Engineering,Wuhan University,Wuhan 430072,China;School of Architectural and Civil Engineering,Sanming University,Sanming 365004,China;Department of Mechanics,Xi'an University of Science and Technology,Xi'an 710054,China;School of Civil Engineering and Architecture,Xi'an University of Science and Technology,Xi'an 710054,China)

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430072 [2]三明学院建筑工程学院,福建三明3650043 [3]西安科技大学力学系,陕西西安710054 [4]西安科技大学建筑与土木工程学院,陕西西安710054

出　　处：《岩土工程学报》2023年第12期2594-2603,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51178358,42107175)。

摘　　要：锚固体与围岩有效黏结是保证锚杆(索)系统正常工作的重要前提,为研究黏土岩内水泥锚固体在拉拔荷载作用下的滑移脱黏机理,开展黏土岩三轴试验、黏土岩-水泥砂浆界面直剪试验和水泥锚固体拉拔的物理模型试验,基于有限-离散元方法(FDEM),建立黏土岩-水泥砂浆的二元体模型,对水泥锚固体拉拔过程进行模拟。研究表明:黏土岩黏聚力小于黏土岩-水泥砂浆界面的切向黏结强度,低法向压力时二元体的剪切破坏多为黏土岩的剪切破坏,但黏土岩内摩擦角较大,高法向压力下界面抗剪强度低于黏土岩,二元体剪切破坏逐渐转变为界面脱黏;考虑剪切失效的双线性黏聚力模型在模拟软岩破坏时是适用的,而二元体黏结界面更适合通过黏结-摩擦模型模拟;水泥锚固体拉拔失效过程可分为黏结变形阶段,界面脱黏阶段,剪胀咬合阶段和滑移阶段4个阶段,界面脱黏后,锚固体附近黏土岩的剪切破坏也是导致锚固失效的重要因素,剪胀咬合阶段的咬合力决定了锚固体的峰值抗拔能力。研究结果对于软岩地区锚固结构设计有一定的指导作用。The bond between an anchor and the surrounding rock is the key factor to ensure the effectiveness of the anchorage system.To study the pull-resistance capacity of cement anchor in clay rock and the debonding mechanism of the interface under pull loads,the triaxial tests on clay rock,the direct shear tests on clay rock-cement mortar(C-C)interface,and the physical model for cement anchor pull-resistance tests are carried out.Based on the finite discrete element method(FDEM),the model for C-C binary is established,and the drawing process of cement anchor is numerically simulated.The researches show that the cohesion of clay rock is less than the tangential bond strength of the C-C interface.The internal tangent of friction angle of clay rock is larger than the friction coefficient of the C-C interface.Therefore,the shear failure of the binary gradually changes from the shear failure of clay rock to the shear debonding of the interface with the increase of the normal pressure.The bilinear cohesive model is available to simulate the failure of clay rock.The bonding interface of the binary is more suitable to be simulated by the bonding-friction model rather than the bilinear cohesive model.The failure process of cement anchor can be divided into four stages:bonding deformation stage,interface debonding stage,shear dilatancy&bite stage,and slip stage.In addition to the interface debonding,the shear failure of clay rock near the anchor is also an important factor leading to anchor failure.The bite force at the shear dilatancy stage determines the peak pull-resistance capacity of the anchor.The research results may play a guiding role in the design of anchorage structures in soft rock areas.

关 键 词：二元体界面 黏聚力单元 剪胀作用 锚杆(索)锚固体 有限-离散元方法 

分 类 号：TU452[建筑科学—岩土工程]