爆破荷载下围岩及支护锚杆动力响应特征模型试验研究  

Model test study on dynamic response characteristics of host rockmass and supporting bolt under blasting load

作　　者：陈士海[1,2] 宫嘉辰 胡帅伟[1] CHEN Shi-hai;GONG Jia-chen;HU Shuai-wei(College of Civil Engineering,Huaqiao University,Xiamen,Fujian 361021,China;Fujian Research Center for Tunneling and Urban Underground Space Engineering,Huaqiao University,Xiamen,Fujian 361021,China)

机构地区：[1]华侨大学土木工程学院,福建厦门361021 [2]华侨大学福建省隧道与城市地下空间工程技术研究中心,福建厦门361021

出　　处：《岩土力学》2020年第12期3910-3918,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51974136);爆炸冲击防灾减灾国家重点实验室开放课题(No.DPMEIKF201307);华侨大学科研基金项目(No.13BS402)。

摘　　要：为了研究爆破荷载下围岩及支护锚杆动力响应特征,借助地下工程模型试验系统,开展了三维动态加载物理模型试验,采用电火花震源代替传统炸药,测试了爆破地震波在围岩中的传播规律和支护锚杆的动力响应特征。试验研究表明,电火花震源具有冲击荷载特性,能够很好地代替传统烈性炸药。爆破地震波的径向加速度峰值以及轴向和环向应变峰值沿洞室径向不是逐级递减,而是呈现正负交替波浪式衰减;加速度峰值沿洞室轴向基本上呈现非线性逐渐递减。加速度峰值受震源荷载幅值的影响较大,即震源荷载越大,同一测点加速度峰值越大。另外,测量了爆破荷载作用下支护锚杆的振动特性,发现对于加长锚固锚杆,自由段主要以受拉状态为主,锚固段拉压状态都存在。锚固段和自由段的最大拉应变大致相同,而锚固段的最大压应变远大于自由段,而且锚固段和自由段振动持续时间大致相同。对于全锚锚杆,锚杆既存在拉伸状态,又存在压缩状态,拉伸应变大于压缩应变。对于端锚锚杆,其受力状态主要以受拉状态为主,拉伸应变远大于压缩应变。研究结论不仅具有重要的理论意义,也能够为地下洞室支护设计提供可预见性指导。To study the dynamic response characteristics of host rockmass and supporting bolt under blasting load, a three-dimensional dynamic loading physical model test was performed using an underground engineering model test system. The propagation law of blasting seismic wave and the dynamic response characteristics of supporting bolt were tested using electric spark source instead of traditional explosives. Experimental research results show that the electric spark source has the characteristic of the impact loading, which can well replace traditional high explosives. The radial acceleration peak values and the axial and hoop strain peak values of blasting seismic wave within host rock do not decrease gradually as the increasing of the radial distance along the excavation, but show a wave-like attenuation pattern of positive and negative alternating. In addition, the acceleration peak values show a nonlinear and decrease gradually along the excavation axial direction. The peak acceleration values are affected largely by the seismic load amplitude, that is, the higher the source load, the higher the peak acceleration value at the same measurement point. In addition, the vibration characteristics of the supporting bolt were measured under blasting load. It is found that the extension anchor bolt, the free section of the anchor bolt is mainly in tension state, but the anchor section of the bolt is in the state of both tension and compression. The maximum tensile strain of the anchor and free section is approximately the same, while the maximum compressive strain of the anchor section is much larger than that of the free section. The vibration duration of anchor section and free section is also approximately similar. As for the full-anchored bolt, the bolt has subjected both a tensile state and a compressive state, and the tensile strain is greater than the compressive strain. As for the end-anchored bolt, the stress state is mainly in the tension state, and the tensile strain is much greater than the compressive strain.

关 键 词：模型试验 电火花震源 爆破地震波 支护锚杆 动力响应 

分 类 号：TU457[建筑科学—岩土工程]