岩溶隧道富裂隙围岩的爆破力学特性分析

Analysis on Mechanical Characteristics of Fissure-Rich Surrounding Rock Blasting of Karst Tunnel

为研究岩溶隧道富裂隙围岩爆炸过程中应力波的传播与衰减规律,运用ANSYS/LS-DYNA软件对隧道岩体中含不同充填介质、不同宽度和不同爆源距离的岩溶裂隙进行了数值模拟。结果表明:爆炸应力波在岩溶裂隙处的传播主要受裂隙内充填介质的物理力学性质的影响,其次受到裂隙宽度、爆源与裂隙距离和爆源强度等因素的影响。充填介质的强度越小,波阻抗也越小,对介质中应力波的阻隔作用则越大。裂隙与爆源的距离越远,爆源强度越小,有效应力峰值也越小。裂隙越宽,对应力波的削弱越大。结合该结论对岩溶隧道裂隙围岩在爆破过程中出现的实际问题进行分析,找出了影响爆破效果的关键因素,通过调整爆破设计参数,得到了不同裂隙围岩条件下爆破参数参考值,经现场测试取得了较好的爆破效果,研究结果可为类似条件下的隧道爆破参数的优化提供理论依据和参考。

The ANSYS / LS-DYNA simulation calculation was applied in order to research the propagation and attenuation rules of stress wave in process of karst tunnel fissure-rich surrounding rock blasting,which covers various karst fissure with diverse media-loaded,width and distance of explosive source. The study shows that the mechanical property of the media-loaded in the fissure has chief impact on blasting stress wave propagation in karst fissure,other factors are on secondary places,as the width of the fissure,the distance and the strength of explosive source,etc. The results show that,less the strength of media-loaded,less the wave impedance,correspondingly greater the resistance on stress wave propagation of dielectric; farther the distance between the fissure and the explosive source,the less strength of explosive source,correspondingly the less effective stress peak; the wider fissure and the greater stress wave attenuation. The research reveals different blasting reference value under different fissure rock condition by undertaking spot test and experiment which solved the practical problems in process of karst tunnel fissure-rich surrounding rock blasting and obtained better blasting effect from which the key factors on rock blasting was discovered and the blasting designed value was adjusted accordingly. The research result shall offer optimized blasting parameters and construction methods in theory and method to those tunnel blasting under similar condition.