花岗岩球砾法向恢复系数试验研究

发布时间：2018-01-13 22:02

本文关键词：花岗岩球砾法向恢复系数试验研究　出处：《岩石力学与工程学报》2017年03期 　论文类型：期刊论文

【摘要】：法向恢复系数是岩崩块石运动分析的关键参数,其取值直接决定了块石的运动轨迹。为了严格测定花岗岩球砾碰撞的法向恢复系数,分析其影响因素,试验采用自行设计的碰撞试验装置和声频采样技术,精确测定花岗岩球砾碰撞的法向恢复系数,研究球砾大小、碰撞速度、含水状态和板的弹性特性4个因素对恢复系数的影响;并基于弹性接触理论推导出碰撞过程的最大接触应力P_(0,max)、碰撞起裂速度v_(ci)和碰撞损伤速度v_(cd),构造接触应力割线变化率k来描述碰撞过程的率相关,分析碰撞法向恢复系数的尺寸效应和速率效应,对碰撞过程耗能机制进行探讨。试验结果表明:花岗岩球砾法向恢复系数存在明显的尺寸效应,低速下更加显著;法向恢复系数的速率效应同样较明显,并且速率效应受球砾尺寸和板的弹性特性影响,呈现较强的相关性;球砾大小和速度相同时,等效弹性模量E*越大,法向恢复系数越小;含水状态对法向恢复系数影响不大。理论分析表明:P_(0,max)和k为控制法向恢复系数变化规律的内在因素;尺寸和速度均是通过改变P_(0,max)和k使法向恢复系数呈现复杂的尺寸效应和速率效应。
[Abstract]:Normal recovery coefficient is the key parameter of rock mass movement analysis, and its value directly determines the movement track of block stone. In order to determine the normal recovery coefficient of granite ball-gravel collision strictly, the influencing factors are analyzed. By using the self-designed impact test device and audio sampling technology, the normal recovery coefficient of granite ball-gravel collision is accurately measured, and the size and impact velocity of the boulder are studied. The effects of water state and elastic properties of the plate on the recovery coefficient; Based on the elastic contact theory, the maximum contact stress of the collision process is derived, and the maximum contact stress P _ S _ 0, the collision initiation velocity and the collision damage velocity are derived. The tangent rate of contact stress k is constructed to describe the rate correlation of the collision process, and the size effect and rate effect of the normal recovery coefficient of the collision are analyzed. The mechanism of energy dissipation during collision is discussed. The experimental results show that the normal recovery coefficient of granitic boulders has obvious size effect, especially at low speed. The rate effect of normal recovery coefficient is also obvious, and the rate effect is affected by the size of boulder and the elastic property of plate. The greater the equivalent modulus of elasticity E * is, the smaller the normal recovery coefficient is when the size and velocity of the ball gravel are the same. The theoretical analysis shows that the normal recovery coefficient is controlled by the internal factors of the rule of normal recovery coefficient: (1) Pak 0 max1) and k (K) and K are the internal factors controlling the change of normal recovery coefficient. Both the size and the velocity are changed by changing PIM and k to make the normal recovery coefficient show complex size effect and rate effect.
【作者单位】：武汉大学土木建筑工程学院;
【基金】：国家自然科学基金资助项目(41272342)~~
【分类号】：TU45
【正文快照】： 1 引言岩质边坡崩塌是自然界中常见的地质灾害之一,对山区公路、桥梁、铁路、房屋建筑等构成了严重威胁[1-3]。M.D.Cruden和J.D.Varnes[4]将这种地质灾害分为2个阶段:第一阶段为岩体从边坡上剥离;第二阶段为剥离后岩块在边坡上下落、碰撞和翻转的运动过程。对于易岩崩的地区

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