爆破开挖扰动下锚固节理岩质边坡位移突变特征与能量机理  

Displacement mutation characteristics and energy mechanisms of anchored jointed rock slopes under blasting excavation disturbance

作　　者：杨建华[1] 代金豪 姚池[1] 胡英国[2] 张小波 周创兵[1] YANG Jianhua;DAI Jinhao;YAO Chi;HU Yingguo;ZHANG Xiaobo;ZHOU Chuangbing(School of Civil Engineering and Architecture,Nanchang University,Nanchang 330031,Jiangxi,China;Changjiang River Scientific Research Institute,Wuhan 430010,Hubei,China)

机构地区：[1]南昌大学建筑工程学院,江西南昌330031 [2]长江水利委员会长江科学院,湖北武汉430010

出　　处：《爆炸与冲击》2022年第3期135-146,共12页Explosion and Shock Waves

基　　金：国家自然科学基金(U1765207,51969015,52179102);江西省自然科学基金(20192ACB21019,20204BCJ23002);江西省重点实验室计划项目(20181BCD40003)。

摘　　要：针对白鹤滩水电站左岸坝基河谷底部边坡岩体爆破开挖,采用现场岩体位移监测、锚索轴力监测及数值模拟的手段,研究了爆破开挖扰动下锚固节理岩质边坡的位移突变特征及其能量机理。研究结果表明:对于深切河谷底部高地应力边坡岩体爆破开挖,爆炸荷载挤压及地应力作用下,岩体所积聚的应变能快速释放,导致了节理岩质边坡的位移突变,突变位移包括节理张开位移和岩体回弹位移两部分;地应力水平越高、岩体弹性模量越低,总的突变位移量越大;预应力锚索主要通过抑制节理张开位移来控制边坡岩体的位移突变,锚索预应力等级越高,其吸能和释能速率越高,对节理岩体位移突变的控制效果越好,当锚索的预应力等级高到一定程度后,节理岩体的突变位移不再随锚索预应力等级的升高而显著减小。The stability of anchored jointed rock slopes under dynamic disturbance of blasting excavation is a major concern for designers and constructors. For the left-bank slope at the valley bottom of the Baihetan hydropower station, the displacement characteristics and related energy mechanism of the anchored jointed rock slope under blasting excavation disturbance were investigated. The field monitoring data of the rock mass displacement and the anchor cable axial force were first presented to show their synchronous mutation characteristics under blasting excavation disturbance. A three-dimensional numerical simulation was then conducted by using FLAC3D to reveal the energy mechanism of the rock mass displacement mutation. The controlling effect of prestressed anchor cables on the rock mass displacement mutation was finally analyzed from the perspective of energy absorption and release. The results show that for the blasting excavation of the rock mass subjected to high in-situ stress at the valley bottom, the displacement mutation of the jointed rock slope is attributed to the rapid release of accumulated strain energy. The accumulated strain energy originates two actions, one is the blasting pressure, and the other one is the in-situ stress. The abrupt displacement of the jointed rock slope includes joint opening displacement and rock springback displacement. The total abrupt displacement will increase as the result of the in-situ stress level increases and the elastic modulus of the rock mass decreases. The prestressed anchor cable has a restraining effect on the displacement mutation of the jointed rock slope, and it mainly controls the joint opening displacement. The anchor cable with a higher prestress level corresponds to higher energy absorption and release rates, and thus has a stronger restraint on the displacement mutation of the jointed rock slope. However, when the prestress of the anchor cable is increased to a higher level, the displacement mutation of the jointed rock slope no longer decreases signific

关 键 词：边坡 节理岩体 预应力锚索 爆破开挖 位移突变 

分 类 号：O382.2[理学—流体力学]