硬岩隧洞下穿高速公路爆破方案与振动特征分析

Blasting scheme and vibration characterization analysis of hard rock tunnel underpass expressway

基于山茶隧洞下穿高速公路的工况背景,采用导坑法进行开挖,制订了详细的爆破、监测方案,并对测试结果进行分析。分析得出:导坑法开挖可以有效控制爆破振动能量和提高单次循环进尺效率;3个振速分量V_(z)>V^(x)>V_(y),将z方向振速作为下穿段高速公路安全允许振速的判据标准;质点峰值振速与装药量成正比,与测点距离成反比;主振频域分布在50~250 Hz,属于中高频段;当周边孔同时起爆且孔数较多时,会导致瞬时能量凸高,可适当增加周边孔起爆段别,避免能量叠加造成的危害。

Based on the working condition of Shancha Tunnel underpass expressway,the heading method is used for excavation,and a detailed blasting and monitoring scheme is formulated.Moreover,the test results are analyzed.It is concluded that the heading method excavation can effectively control the blasting vibration energy and improve the efficiency of single cycle footage.Three vibration velocity components are V_(z)>V_(x)>V_(y),and the z-direction vibration velocity is used as the criterion for the safety allowable vibration velocity of the underpass section of the expressway.The peak velocity of the particle is proportional to the charge quantity and inversely proportional to the distance of the measuring point.The main vibration frequency domain is distributed in 50-250 Hz,which belongs to the middle and high frequency band.When the peripheral holes are detonated at the same time and the number of holes is large,the instantaneous energy will be sharply increased.The detonation section of the peripheral holes can be appropriately increased to avoid the hazards caused by energy superposition.