水平层状围岩隧道爆破控制技术

发布时间：2018-08-08 16:41

【摘要】：针对水平层状围岩隧道开挖时,由于水平层理的影响以及爆破扰动,极易导致隧道拱部发生离层、掉块以及严重的超挖、欠挖等问题。采用爆破应力波传播理论分析了爆破应力波对水平节理岩体的作用机理,从理论上解释了水平层状围岩隧道拱顶发生离层、平顶的原因;依托大梁峁公路隧道工程进行现场爆破参数优化试验;并针对拱部超挖严重,上台阶下部边墙欠挖的情况,提出了控制措施。研究结果表明:通过爆破参数优化,上台阶开挖单次爆破可减少6%的起爆药量,下台阶可减少29%的起爆药量;从爆破效果来看,优化后6个试验断面平均超挖由原来的7.81m2减少为2.56m2,优化后超挖面积仅为优化前的31%,欠挖也得到有效改善,优化后的爆破方案不仅能大幅减少隧道超欠挖,减少炸药用量,还能提高开挖后围岩的质量,使隧道施工更安全;拱部超挖可通过内移周边眼、适当增加周边眼间距、减少装药量以及非连续装药等措施进行控制;上台阶下部边墙欠挖可通过缩小周边眼间距或增设周边眼等措施来解决。研究成果不仅可保证依托工程的施工安全,减少超欠挖,节约成本,加快施工进度,还可为类似工程提供参考。
[Abstract]:Due to the influence of horizontal stratification and blasting disturbance in excavation of horizontal layered surrounding rock tunnel, it is easy to cause the tunnel arch to be separated from the layer, to drop blocks and to cause serious over-excavation and underexcavation. The mechanism of blasting stress wave acting on horizontal jointed rock mass is analyzed by using the theory of blasting stress wave propagation. The field blasting parameter optimization test is carried out based on the Dahangshan highway tunnel project, and the control measures are put forward in view of the serious overexcavation of the arch and the underexcavation of the upper and lower side wall. The results show that by optimizing the blasting parameters, the explosive quantity can be reduced by 6% in single blasting and 29% in the lower step. After optimization, the average over-excavation of the six test sections is reduced from the original 7.81m2 to 2.56 m2, the area of over-excavation after optimization is only 31% of that before the optimization, and the under-excavation is also effectively improved. The optimized blasting scheme can not only greatly reduce the over-underexcavation of the tunnel, but also reduce the amount of explosive. It can also improve the quality of surrounding rock after excavation and make the tunnel construction safer, and the arch overexcavation can be controlled by the measures of moving in the peripheral hole, increasing the distance between the peripheral eyes, reducing the charge quantity and discontinuous charge, etc. The underexcavation of the lower side wall of the upper steps can be solved by reducing the distance between the peripheral eyes or adding the peripheral holes. The research results can not only guarantee the construction safety of the project, reduce the over-underdigging, save the cost and speed up the construction progress, but also provide a reference for similar projects.
【作者单位】：长安大学公路学院;西安工业大学建工学院;
【基金】：教育部长江学者奖励计划项目(T2014214) 国家自然科学基金项目(51278063) 陕西省重点科技创新团队支持计划项目(2014KCT-29) 陕西省交通运输厅建设科技项目(13-14K) 陕西省教育厅专项科技计划项目(15JK1337)
【分类号】：U455.6

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