半煤岩巷道掘进爆破振动监测分析
Analysis on Monitoring of Blasting Vibration in Semi Coal and Rock Roadway Excavation
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摘要: 为研究半煤岩巷道掘进爆破振动规律及其对围岩松动圈的影响,以新驿煤矿半煤岩段巷道为试验地点,开展了爆破振动及松动圈现场测试。分析爆破振动监测数据表明:半煤岩巷道掘进爆破主振频率在50~250 Hz,同段雷管起爆的药量较大时引起爆破主振频率较高;实测爆破振动速度大于理论计算值,借助萨式公式回归拟合了爆破振动衰减公式,并计算了不同岩层爆破安全允许距离。分析松动圈检测数据表明:砂岩层围岩松动圈范围为1~1.25 m,煤层围岩松动圈为1.25~1.5 m;爆破振动对砂岩层围岩扰动较小,对煤层围岩松动圈增加了约0.2 m;随着自由面的增多,爆炸总能量在岩体内传播随之减少,此时爆破振动对围岩扰动变小。基于监测分析成果,提出了装药结构、支护参数等方面改进措施。Abstract: To study the regularity of blasting vibration of semi coal and rock roadway and its influence on the broken rock zone, the semi coal and rock roadway of Xinyi Coal Mine is taken as the test site, and the field test of blasting vibration and broken rock zone is carried out. The monitoring data analysis of blasting vibration shows that the main vibration frequency of excavation blasting in semi coal and rock roadway is 50 Hz to 250 Hz, and the main frequency of blasting vibration is higher when the detonating charge of the same section of detonator tube is large. The measured blasting vibration velocity is higher than the theoretical value, and the blasting vibration attenuation formula is fitted by using Sadov’s formula regression, then the permissible safe distance of blasting in different rock layers is calculated. The analysis of the test data of the broken rock zone shows that the range of the broken rock zone of sandstone layer surrounding rock is 1 m to 1.25 m, and the range of coal seam surrounding rock is 1.25 m to 1.5 m. The blasting vibration has little disturbance to the surrounding rock of sandstone layer, and the broken rock zone of coal seam increases by about 0.2 m. With the increase of free surface, the propagation of total explosion energy in rock mass decreases, and the disturbance to surrounding rock by blasting vibration becomes smaller. Based on the results of monitoring and analysis, the improvement measures of charging structure and supporting parameters are put forward.