爆破荷载下喷锚支护动载响应的数值分析

Numerical analysis of response to dynamic loads of shotcrete and bolt support under blasting loads

喷锚支护广泛应用于采矿巷道支护、交通隧道支护、地下硐室加固等工程中。利用显式动力分析软件LS-DYNA,对微差爆破作用下喷锚支护的动态力学性能进行分析,比较了4种不同爆破方案下混凝土支护的受力与振动特性以及锚杆轴力的变化特点。结果表明:采用25ms的延期时间,微差爆破能够有效减弱爆炸应力的破坏效应;当爆炸应力作用在拱顶时,锚杆安装角越低,所受轴向应力越小;巷道拱顶锚杆交替承受拉压应力,水平锚杆主要承受拉应力。将数值模拟结果与冬瓜山铜矿现场情况相结合,提出了巷道支护的修改方案。

The shotcrete-bolt support is widely used in mine roadway support, traffic tunnel support, reinforcement of underground excavation. The dynamic mechanical properties of shotcrete-bolt support under millisecond blasting are analyzed by using LS-DYNA software. The stress and the vibration characteristics of concrete support and variation characteristics of axial stress of bolt under four different blasting plans are compared. The results shows that the destructive effects of blasting can be effectively weakened by using millisecond blasting, and the delay time is 25ms. When the blasting stress acts on arch cover, and the installation angles of anchor bolt is low, the axial stress of rock bolts is lower. The bolts on arch cover bear pressure and tension alternately, and the bolts in horizontal direction bear tension principally. The modification scheme for roadway support is proposed on the basis of combining numerical simulation result and field condition of Dongguashan copper mine.