江洲深基坑下伏基岩爆破开挖危害控制研究

Risk control study for the blasting excavation of underlying bedrock in the deep foundation pit in Jiangzhou

建基坑工程中,下伏基岩爆破施工需确保基坑围护结构及其相邻环境的安全。针对橘子洲深基坑爆破施工的实际需要,运用LS-DYNA建立全尺寸三维模型,分别对垂直炮孔、水平炮孔的爆破进行了对比模拟分析,通过对基坑底板、地下连续墙结构及紧临建筑物爆破震动的安全评估,得到不同炮孔布置方式的爆破差异,并在此基础上提出了针对性爆破施工建议。

This paper is mainly aimed to study the impacts of the strong blasting vibration on the foundation pit engineering project.As is known,it is very difficult to ensure the safety of the engineering project itself as well as its surrounding areas as a result of conducting a strong blasting construction.It is just for this urgent need that we have established a 3-D calculation model via a computer software named ANSYS/LS-DYNA.In addition,we have also managed to conduct some numerical simulations with the help of the above software and gained necessary data and information that can help us to provide valuable references to the design of such actual blasting construction projects.At the same time,we have also made an exploration of the necessary tolerable safety factors of the foundation pit by using dynamites of varying sizes.And,then,we have examined and compared the simulation results of the vertical and horizontal blasting,trying to find different effects gained from the different blasting ways on the surrounding constructions,such as on the base plate,the diaphragm wall and the surrounding buildings.The investigation and exploration of the simulation results help us to conclude that it is better to choose the horizontal blasting as a dominating blasting mode instead of the vertical blasting one,which should be taken as an auxiliary blasting one.In so doing,we can significantly reduce the impacts on the surrounding constructions.What is more,if the distance of the region and the blasting point were over 10 meters,the horizontal vibration velocity would be much better fit than the vertical one.Therefore,it is necessary for us to reinforce the monitoring activities in accordance with the corresponding horizontal vibration of diaphragm walling structure.From what is stated above,it can be seen that the conclusive finding made in this study can serve as a valuable reference to the design and construction of the foundation pits under similar conditions.