摘要
爆破振动灾害严重威胁着爆破振动场内既有构筑物的安全及稳定。然而,由于毫秒延时爆破的振动载荷表征复杂,若采用简化的三角形或者梯形动力载荷进行分析,与实际的工程情况差异显著。基于对爆破孔内爆破压力变化、炮孔体积扩张、围岩裂隙发展、爆破气体运动等的分析,建立起爆破动力载荷随时间变化的精确数学模型;在远场爆破振动分析时,统一理论下各个爆破孔的动力载荷,其规律满足圣维南定理,因此,可将每分段内各孔的爆破载荷等效为其作用区域上的均布载荷,毫秒延时爆破问题就转化为一个等效边界问题;最后通过有限元数值模拟软件FLAC3D建立三维隧道模型,代入物理力学参数、传播及衰减规律参数以及动力载荷模型,预测峰值速度曲线,与现场实际监测数据进行对比分析,确定数值模拟的准确性,并结合预测的有效应力曲线计算得出爆破安全判据公式。
Blasting vibration damages have serious threats on the safety and stability of existing constructions. However, the dynamic loading in millisecond delay blasting is very complicated. There must be significant differences from actual engineering conditions when adopting simple triangle or trapezoid dynamic loading to analyze such vibration problems. Based on the analysis of pressure changes, volume expansion, fracture developments and gas motions in the blasting holes, an accuracy model of blasting loading over time was proposed. Also, for the far field vibration, the dynamic loading of each blasting hole was satisfied by the unified theory and Saint Venant＇s theorem. Thus, the dynamic loading of each blasting hole equaled the uniformly distributed loading on its cutting surface. In this way, the millisecond delay blasting problem was transformed into an equivalent boundary problem. Finally, a numerical model was built by the FLAC3D software. The physics and mechanics parameters, the propagating and damping parameters, and the dynamic loading model were used to predict the peak velocity curves. Compared with the measured in-situ data, the accuracy of the simulation was verified and the safety criterion formulas were calculated with the predicted effective tensile stress curvcs.
出处
《工程力学》
EI
CSCD
北大核心
2015年第10期123-129,共7页
Engineering Mechanics
基金
硬岩原位低强度破坏机理及相关试验技术研究项目(YETP0344)
采煤机工作可靠性智能监测技术项目(2013AA06A411)
