深圳赤湾停车场基坑工程场地平整控制爆破试验研究

Experimental Study on Controlled Blasting of Foundation Flatness for Foundation Pit of Chiwan Parking Lot in Shenzhen

岩石地基开挖的平整性与完整性直接影响着工程质量与进度,为了使深圳赤湾停车场基坑开挖工程同时满足开挖的经济高效性及地基的平整完整性,将垂直孔复合消能爆破技术应用到工程中。基于工程原8 m及12 m台阶爆破参数,以炮孔间排距作为主要变量设计了多组现场爆破试验。试验中不改变原爆破联网方式、单孔装药结构及炸药单耗等参数,将同一次起爆区分为常规区及消能试验区以做对比。爆破堆渣清除后,用RTK定位系统测量地基高程数据,建立了三维地表模型图;同时结合统计结果分析了垂直孔复合消能爆破技术对地基平整度的影响。结果发现:在两种不同高度的台阶爆破试验下,垂直孔复合消能爆破技术均能使爆破后地基的平整度更优;此外,孔间排距是影响爆破效果的重要因素,为使地基平整度最好,工程中8 m台阶爆破参数下最优间排距为2.0 m×2.0 m,12 m台阶爆破参数下则为4.0 m×4.5 m,为现场施工运用提供了相关依据。

The leveling and integrity of rock foundation excavation directly affects the quality and progress of the project.In order to make the foundation pit excavation of Shenzhen Chiwan parking lot meet the demand of economic efficiency with high leveling & integrity,the technology of vertical-hole shock reflection blasting is applied in the project.Based on the original 8 m and 12 m bench blasting parameters of the project,multiple groups of field blast tests were designed with the spacing between the holes as the main variable.During the test,the parameters such as the original blasting networking mode,single-hole charging structure and unit consumption of explosives kept the same,and the blasting initiation area is divided into conventional area and energy dissipation test area for comparison.After the blasting muck pile is removed,RTK positioning system is used to measure the ground elevation data and establish the 3 D surface model map.At the same time,the influence of vertical-hole shock reflection blasting technology on the flatness of foundation is analyzed.The results show that the vertical-hole shock reflection blasting technique can improve the flatness of foundation under bench blasting tests with different heights.In addition,the spacing between holes is an important factor affecting the blasting effect.To ensure the best flatness of the foundation,the optimal spacing between holes under 8 m bench is 2.0 m 2.0 m and 4.0 m 4.5 m for 12 m bench,which provides relevant basis for field construction and application.