基于PFC^(2D)隧洞注浆混凝土三点弯曲梁破坏模拟  

Based on PFC^(2D) Tunnel Injection Layer Concrete Three-point Bending Beam Destruction Simulation

作　　者：田林昌 季日臣[1] TIAN Lin-chang;JI Ri-chen(School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China)

机构地区：[1]兰州交通大学土木工程学院,兰州730070

出　　处：《科学技术与工程》2022年第2期757-764,共8页Science Technology and Engineering

基　　金：国家自然科学基金(51969011);甘肃省科技计划(20JR10RA274)。

摘　　要：为研究输水隧洞回填灌浆层混凝土在上部围岩压力的作用下的破坏模式,建立PFC^(2D)隧洞模型分析沉降,利用PFC^(2D)颗粒流程序及该程序自带平行黏结模型,将回填灌浆层混凝土简化为一个三点弯曲梁模型,通过改变给上部圆形加载墙施加不同加载速度和赋予颗粒的平行黏结模量这两个关键因素,研究了模型应力、力链、胶结破坏能,以及从微观角度研究加载时颗粒内部位移变化。结果表明:隧洞上部围岩沉降约3.6 cm,试件受压使裂纹发展,导致试件内部应力状态发生改变,不同加载速度下产生拉伸裂纹和剪切裂纹,两种类型的裂纹产生时间和数量有较大差别,同时内部力链在裂纹初现时出现集中现象,强、弱力链所代表的接触力减小。裂纹处胶结状态破坏,在不同加载速度和平行黏结模量下胶结破坏能大小各不相同。In order to study the destruction mode of the backfilling grout layer concrete under the pressure of the upper surrounding rock,the PFC^(2D) tunnel model was established to analyze the settlement,and the PFC^(2D) particle flow program and the program come with its own parallel bonding model.Backfilling grout layer concrete was simplified into a three-point curved beam model,by changing the two key factors of applying different loading speeds to the upper circular loading wall and the parallel bonding modulus that give particles,the model stress,force chain,bond destruction energy,and study the changes in the internal displacement of particles at load from a microcosmic perspective.The results show that:about 3.6 cm of the upper perimeter rock settlement of the tunnel,the test piece is subjected to fracking development,resulting in the change of the internal stress state of the test piece,the tensile crack and shear crack at different loading speed,the time and quantity of the two types of crack generation are quite different,while the internal force chain is concentrated at the beginning of the crack,and the contact force represented by the strong and weak force chain is reduced.The bonding state is destroyed at the crack,and the size of the bonding damage energy varies at different load speeds and parallel bonding modulus.

关 键 词：颗粒流模拟 隧洞沉降 豆砾石 三点弯曲梁 混凝土破坏 

分 类 号：TV431[水利工程—水工结构工程]