立井冻土不同含水率下的爆破模拟试验

Simulation test of vertical shaft blasting in frozen soil with different moisture content

立井冻土爆破开挖对冻结壁及冻结管产生振动影响,危害施工安全。通过开展立井冻土爆破模拟试验,分析了不同爆破参数下的振动传播衰减规律。结果表明:单孔爆破时,10%含水率冻土爆破引起的振动速度较大,为15%含水率冻土爆破的3倍,爆炸应力波主要由爆源向周围径向传播,引起未开挖土体的振动大于已开挖侧;双孔爆破时,10%含水率、15%含水率的振速表现差异较大;含水率为10%爆破时,工作面未开挖侧10cm附近三向振速较小,向两侧逐渐增大;含水率为15%爆破时,振速未表现出明显规律;四孔爆破,由于中空孔的存在,爆破能量充分释放,工作面两侧振速小于单孔爆破,爆破效果较好。

Blasting excavation of frozen soil in vertical shaft has vibration effect on frozen wall and freezing pipe,which endangers construction safety.Through the simulation test of frozen soil blasting in vertical shaft,the attenuation regularity of vibration propagation under different blasting parameters was analyzed.The results show that the vibration velocity caused by 10%moisture content frozen soil blasting is three times that of 15%moisture content frozen soil blasting in single hole blasting.The blasting stress wave mainly propagates from the explosion source to the surrounding radial direction,which causes the vibration of the unexcavated soil to be greater than that of the excavated side.The vibration velocities of 10%moisture content and 15%moisture content are quite different in double-hole blasting.When the water content is 10%,the three-dimensional vibration velocity near the 10cm of the unexcavated side of the working face is small,and gradually increases to both sides.When the moisture content is 15%,the vibration velocity shows no obvious regularity.In case of four-hole blasting,due to the existence of hollow holes,blasting energy is fully released,and the vibration velocity on both sides of the working face is less than single-hole blasting,so the blasting effect is better.