不同爆炸力作用下端部消波和加密锚杆支护洞室动态响应研究

Dynamic responses of underground openings with end weakened by holes and anchor top reinforced by dense rock bolts under different explosion forces

基于模型试验,研究了不同爆炸力作用下端部消波和加密锚杆支护洞室的动态响应。在不同爆炸力作用下,三个洞室的拱顶垂直压应力峰值、顶底板相对位移峰值、最大洞壁压应变峰值和拱顶加速度峰值与比例距离呈幂函数衰减规律,并拟合出相应的幂函数曲线。随着比例距离的减小,离端部加密锚杆支护洞室与长密锚杆支护洞室最近测点的垂直压应力峰值的拟合曲线几乎重合,端部消波支护洞室的垂直压应力峰值从比端部消波锚杆和长密锚杆支护洞室大向比它们小转变,大约在比例距离0.6 m·kg^(-1/3)处,三个洞室的垂直压应力峰值相等;端部消波和加密锚杆支护洞室的顶底板相对位移峰值逐渐向长密锚杆支护洞室靠近,当比例距离小于0.8 m·kg^(-1/3)开始超过长密锚杆支护洞室;端部加密锚杆支护洞室与长密锚杆支护洞室的最大洞壁压应变峰值曲线比较靠近,端部消波锚杆支护洞室的最大压应变峰值从比长密锚杆支护洞室小逐渐向比长密锚杆支护洞室大转变;端部加密锚杆支护洞室的拱顶加速度峰值从比长密锚杆支护洞室小到比长密锚杆支护洞室大,比例距离为1.55 m·kg^(-1/3)是两种状态的转折点。

Based on model tests,dynamic responses of underground openings with end weakened by holes and anchor top reinforced by dense rock bolts were studied under different explosion forces. The results showed that with increase in scaled distance,peak pressure stress on vault,relative peak displacement between vault and footwall,maximum peak strain and peak acceleration on vault of three underground openings gradually decay according to a power function,respectively,and the corresponding power function curves were fitted; with decrease in scaled distance,the fitted curve for the vertical peak compressive stress of the measured point nearest to the underground opening with anchor top reinforced by dense rock bolts and that of the underground opening with anchor top reinforced by long-dense rock bolts almost coincide,and the vertical peak compressive stress of the underground opening with end weakened by holes is bigger than those of the other two underground openings at the same scaled distance firstly,and then changes to be smaller,and when the scaled distance is 0. 6 m · kg^（-1/3）,the vertical peak compressive stresses of three underground openings are equal; with decrease in scaled distance,the relative peak displacements of the underground opening with end weakened by holes and that of the underground opening with anchor top reinforced by dense rock bolts are gradually close to that of the underground opening with anchor top reinforced by long-dense rock bolts,and when the scaled distance is less than 0.8 m·kg^（-1/3）,both of them begin to exceed the latter; with decrease in scaled distance,fitting curves for the maximum peak strain of the underground opening with anchor top reinforced by dense rock bolts and that of the underground opening with anchor top reinforced by long-dense rock bolts are similar,and the maximum peak strain of the underground opening with end weakened by holes is smaller than that of the underground opening with anchor top reinforced by long-dense rock bolts at the same scaled distance firstly,and then changes to be bigger; with decrease in scaled distance,the peakacceleration on vault of underground opening with anchor top reinforced by dense rock bolts is smaller than that of the underground opening with anchor top reinforced by long-dense rock bolts at the same scaled distance firstly,and then changes to be bigger,the turning point between the two states is the scaled distance of 1. 55 m·kg^（-1/3）.