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根据Froude相似理论,通过模型试验,对普通锚杆、中密锚杆、长密锚杆、短密锚杆、长短相间密锚杆加固洞室的抗爆性能进行了研究,分析了不同长度、间距的全长粘结式锚杆加固洞室在围岩应力、洞壁加速度、洞室拱顶底板相对位移、洞壁环向应变、洞室破坏形态等方面的不同特点。采用FLAC3D对模型试验进行了模拟,并利用参数化建模方法分析了洞顶位移随锚杆长度、间距的变化规律。研究结果表明:减小锚杆间距比增加锚杆长度更能有效地提高洞室抗爆能力,且锚杆间距必须达到一定密度时才可以阻止围岩裂缝进入锚固区;在锚杆长度相同的情况下,密锚杆能明显减小洞室拱顶加速度峰值、拱顶底板相对位移峰值、残余值和拱脚部位压应变峰值、残余值;当锚杆长度增加到一定程度后,加固的效果并不明显,而且带来了底板加速度峰值、拱顶拉应变峰值的增加;锚杆的最佳长度可取为1/3洞室跨度,锚杆的最佳间距可取为1/15洞室跨度。
According to the Froude similarity theory, the antiknock performance of the normal cavern, middle grouted bar, long grout bar, short bolting bar and short and long phase dense bolting reinforcement cavern is studied through model test. The effects of different length, Spacing of the length of the bonded bolt reinforcement caverns in the surrounding rock stress, wall acceleration, the relative displacement of the cavern roof, hole wall circumferential strain, cavity failure morphology and other aspects of the different characteristics. FLAC3D is used to simulate the model test. The parametric modeling method is used to analyze the variation of the displacement of the top of the tunnel with the length and spacing of the anchor. The results show that reducing the bolt spacing can effectively improve the blast resistance of the cavern in order to increase the length of the bolt, and the distance between the bolts must reach a certain density to prevent the cracks in the surrounding rock from entering the anchorage zone. When the bolt length is the same Case of dense bolt can significantly reduce the cavern peak acceleration, peak relative displacement of the dome floor, the residual value and the peak value of the arch foot compressive strain, residual value; when the length of the anchor rod increases to a certain extent, the reinforcement effect But not obvious, but also brought the peak acceleration of the floor and the increase of peak tensile strain of the vault. The optimum length of the anchor rod is 1/3 of the span of the cavern, and the optimum spacing of the anchor rod is 1/15 of the span of the cavern.