硬岩体强度弱化范围理论分析与工程验证

岩石巷道综合机械化快速掘进有助于改善采掘接续紧张的局面，而岩石硬度是影响综掘设备快速掘进的关键因素之一。针对硬岩巷道围岩岩性特点，利用超深孔预裂爆破技术，对硬岩巷道岩体强度进行弱化，并通过工程实践检验预裂效果，结果表明：硬岩巷道超深孔预裂爆破后，钻孔周围形成压碎区、裂隙区，使岩体有效强度降低，有利于综掘截割机具经济破岩；理论及数值模拟分析得出钻孔爆破后形成半径为1．8 m左右的松动破坏区；通过对新庄孜矿-812 m水平B4胶带大巷硬岩进行超深孔预裂爆破，钻孔窥视及工程验证爆破松动半径能够达到1．5～2．5 m之间，取得了良好的岩体强度弱化效果，为硬岩巷道机械化快速施工技术研究提供指导。

Theoretical Analysis and Engineering Verification of the Range of Hard Rock Strength Weakening

Fully mechanized rapid excavation in rock roadways is helpful to improve the intensive situation of the mining and driving continuance .One of the key factors is the rock hardness , which affects rapid excavation of fully mechanized equipment .Surrounding rock characteristics of hard rock roadways were concerned , the tech-nology of the pre-splitting blasting in deep boreholes was used to weaken hard rocks in roadways , and the engi-neering practice was carried out to examine the effect of pre -splitting .The results showed that after pre -split-ting blasting in deep boreholes , crushed and fractured zones appear around the boreholes , the effective strength of rocks were reduced in the crushed and fractured zones , which ensures economic breaking rocks by fully mech-anized cutting machines .Theoretical analysis and numerical simulation results showed that fractured zone with radius of about 1.8 m appeares after blasting .The technology was used to weaken hard rocks in B 4 belt convayor roadway at -812 m level in Xinzhuangzi Coal Mine .The results by observation in borehols and engineering veri-fication showed that blasting loosen radius reaches 1.5 m to 2.5 m, good weakening results were achieved , which provides important guidance for the mechanized rapid excavation technology research in rock roadways .