在爆炸荷载条件下锚固洞室破坏形态对比试验研究

MODEL TEST STUDY OF FAILURE PATTERNS OF ANCHORED TUNNEL SUBJECTED TO EXPLOSION LOAD

通过物理模型试验,研究洞室在平面装药和集中装药爆炸荷载作用下不同加固方案的对比抗爆效果。简要介绍新研制的岩土工程抗爆结构模型试验装置、模型试验相似条件、平面装药和集中装药爆炸模拟方法,着重给出在爆炸荷载条件下几类锚固洞室模型的破坏形态试验结果。模型试验结果表明,对相同试验条件下的洞室,在平面装药爆炸试验中洞室拱部材料均发生脱落,在集中装药爆炸试验中洞室拱脚均产生剪切错动裂缝;全长黏结式锚索加固的洞室比自由式锚索加固的洞室抗爆效果好;只增加锚杆长度对阻止围岩裂缝的发展不起控制作用,必须在锚杆间距达到一定密度时才可以阻止围岩裂缝进入锚固区;在拱脚局部加长的密锚杆支护可以有效地阻止或者阻断围岩裂缝的发展,或者迫使裂缝绕过锚固区,从而提高锚固洞室的抗爆能力。研究结果对改进地下抗爆结构加固措施,提高其抗爆能力具有重要参考价值。

By model test study,contrast effects of anti-explosion capacity of various reinforced tunnels are gained.In the model test,tunnels bear explosion load including plane charge and mass charge.The model test apparatus for anti-explosion structures in rock and soil engineering,simulation methods of plane charge and mass charge,and similar condition are introduced briefly.It emphatically introduces the fracture pattern of anchored tunnels under the same conditions of explosion load.Some conclusions are drawn from the model test results.Firstly,under the same test conditions,tunnel roof spalling is arisen in the plane charge test,while shear cracks and stagger cracks in tunnel spandrel is arisen in the mass charge test.Secondly,anti-explosion capacity of the tunnel reinforced by full-grouted anchor cables is better than the tunnel reinforced by part-grouted anchor cables.Thirdly,the augmentation of anchor length has no control effects to prevent crack extension in wall rock,only when anchor spacing is to a certain density,it just prevents cracks from extending into the reinforced region.Lastly,local and dense lengthening anchors in tunnel spandrel can prevent or interdict cracks from extending in wall rock,or compel cracks to detour the reinforced region,consequently it enhances anti-explosion capacity of the tunnel.This study has important reference value for amelioration of reinforced measures of the underground anti-explosion structures and enhancement of its anti-explosion capacity.