浅埋暗挖隧道爆破对敏感建筑物的影响及优化

Influence and Optimization of Blasting of Shallow-buried Tunnel on Sensitive Buildings

研究目的:随着城市地铁建设快速发展,施工要求愈发严格,目前已有的研究多为数值模拟研究,对装药方式的改变所带来的影响研究较少,浅埋暗挖隧道爆破施工时对敏感建筑物的影响及优化控制问题亟待解决。本文以重庆地铁项目隧道工程为背景,针对施工过程存在需频繁下穿对环境影响极其敏感的重要建(构)筑物进行优化控制研究。利用理论推导计算不同爆破介质的对比分析并经过数值模拟现场实施验证,优化周边眼的单孔装药量,增加半孔的保留率,控制爆破振动速度。研究结论:(1)相比于空气介质,采用水介的偏心不耦合装药对周边眼的超欠挖控制效果更明显;(2)在现场施工时周边眼装药结构应尽可能选择径向不耦合系数≥2的装药结构;(3)在其他装药参数相同情况下,围岩外侧(装药背离侧)爆破区半径随围岩级别减小总体上呈现持续下降或平稳变动的态势,但随围岩内RQD数值的增加则总体趋势不变;(4)数值模拟最大值结果比实际监测最大值高,这是因为模型对地质条件进行了简化,忽略了地震波在岩层节理及裂隙中传播时的能量损耗;(5)经现场实施验证,经优化后的爆破方案可应用于控制浅埋暗挖隧道爆破施工对敏感建筑物的影响领域。

Research purposes:With the rapid development of urban subway construction,the construction requirements become more and more strict.At present,the existing research is mostly numerical simulation research,and the impact of the change of charging mode is less.The impact of the blasting construction of shallow-buried tunnels on sensitive buildings and the optimization control problem need to be solved.This paper takes the tunnel engineering of Chongqing Metro project as the background,and studies the optimal control of important buildings that need to be frequently crossed during the construction process and are extremely sensitive to the environmental impact.The comparison and analysis of different blasting media are calculated by theoretical derivation and verified by numerical simulation on site.The single hole charge of peripheral holes is optimized,the half hole retention rate is increased,and the blasting vibration speed is controlled.Research conclusions:(1)Compared with air medium,the eccentric uncoupled charge of water medium has more obvious control effect on the overbreak and under-excavation of surrounding holes.(2)The charge structure with radial decoupling coefficient≥2 shall be used as much as possible for the peripheral hole charge of on-site construction.(3)Under the same conditions of other charging parameters,the radius diameter of the blasting area outside the surrounding rock(the charging deviation side)generally presents a continuous decline or stable change with the reduction of the surrounding rock grade,but the overall trend remains unchanged with the increase of the RQD value in the surrounding rock.(4)The maximum value of numerical simulation is higher than the maximum value of actual monitoring,because the model simplifies the geological conditions and ignores the energy loss of seismic wave propagation in rock joints and fractures.(5)After on-site implementation verification,the optimized blasting scheme can be used to control the impact of blasting construction of shallow-buried and underground excavation tunnels on sensitive buildings.