板裂状隧道围岩破裂及突水试验研究

发布时间：2018-05-13 05:07

本文选题：板裂状隧道围岩 + 模型试验　；参考：《西南交通大学》2017年硕士论文

【摘要】：板裂状隧道围岩由于受极发育的层间错动影响而具有明显的结构性,其变形破坏特征更为复杂。尤其在高地应力区脆性硬岩隧道开挖中,板裂化形成的板裂状围岩会产生突发性破裂,破裂强烈时还会出现岩爆等不良地质现象,危及洞内施工人员安全。本文以硬脆性岩体为原型,在遵循相似理论的基础上,通过室内物理模型试验对板裂状隧道围岩破裂及突水的过程与其影响因素进行研究,并结合材料力学压杆稳定问题对板裂状围岩破裂失稳机理进行分析。主要研究工作如下:(1)以硬脆性流纹岩为试验围岩的原型,根据其力学及变形特征,在前人对脆性岩体相似材料的基础上,通过改变石膏、水泥、砂和水四种材料的配比得到满足本次试验岩体物理力学特性要求的模型相似材料;(2)针对模型试验的研究目的,自主研制模型框架、加载及平面应变约束系统,并根据板裂状隧道围岩的特征及原型岩石的力学性质,运用相似理论,设计初始板裂化后形成的直墙板裂状隧道模型,研究其在双轴加载及板间空隙水压作用下围岩变形特征与破坏模式;(3)运用物理模型试验研究了板裂围岩厚度为10mm、20mm及30mm隧道模型,揭示了双轴加载条件下不同板裂围岩厚度隧道的变形特征及直墙板裂化围岩的破坏过程,并对比分析了隧道围岩各变形阶段的应力分布规律;(4)通过对板裂厚度为30mm的隧道进行板间空隙水压加载破坏试验,揭示了空隙水压作用下板裂状隧道围岩的破坏及突水特征,并与相同板裂厚度双轴加载破坏的隧道模型相对比,得到了两种加载方式下板裂状隧道围岩的破裂过程及应力分布的差异;(5)基于理想弹性假设,采用材料力学压杆稳定原理分析板裂状岩体屈曲破裂机理,结果表明围岩弹性模量越大、板裂厚度越大、板裂高度越小,则轴向临界压应力值越大,并用1#模型试验结果验证了理论的正确性,分析了 2#和3#模型试验与理论结果产生差异的原因。
[Abstract]:The wall rock of slab crack tunnel has obvious structure because of the influence of interlayer dislocation of polar development, and its deformation and failure characteristics are more complex. Especially in the excavation of brittle hard rock tunnel in high in-situ stress zone, the cracking wall rock formed by plate cracking will produce sudden rupture, and the bad geological phenomena such as rockburst will occur when the crack is strong, which endangers the safety of the construction personnel in the tunnel. In this paper, based on the similarity theory of hard and brittle rock mass, the process of wall rock fracture and water inrush of slab cracked tunnel and its influencing factors are studied by laboratory physical model test. Combined with the stability problem of compressive rod in material mechanics, the failure and instability mechanism of cracked wall rock is analyzed. The main research work is as follows: (1) taking hard brittle rhyolite as the prototype of the test surrounding rock, according to its mechanical and deformation characteristics, on the basis of the similar materials of previous people to brittle rock mass, by changing gypsum, cement, According to the research purpose of the model test, the model frame, loading and plane strain constraint system are developed independently for the purpose of the model test. According to the characteristics of the surrounding rock and the mechanical properties of the prototype rock, the model of the straight wall plate crack tunnel formed after the initial plate cracking is designed by using the similarity theory. The deformation characteristics and failure mode of surrounding rock under biaxial loading and interstitial water pressure are studied. The physical model test is used to study the wall rock thickness of 10mm ~ 20mm and 30mm tunnel model. The deformation characteristics of tunnel with different wall rock thickness and the failure process of cracked wall rock with straight wall plate under biaxial loading are revealed. The stress distribution law of tunnel surrounding rock in each deformation stage is compared and analyzed. The failure and water inrush characteristics of the surrounding rock under the action of gap water pressure are revealed through the test of water pressure failure between plates in the tunnel with slab crack thickness of 30mm. Compared with the tunnel model with the same thickness of plate crack under biaxial loading, the difference of the fracture process and stress distribution of the surrounding rock of the slab crack tunnel under two loading modes is obtained. (5) based on the ideal elastic hypothesis, the fracture process of the surrounding rock and the stress distribution of the tunnel under the two loading modes are obtained. The buckling and fracture mechanism of slab-crack rock mass is analyzed by means of the stability principle of compression bar of material mechanics. The results show that the greater the elastic modulus of surrounding rock, the greater the thickness of slab crack and the smaller the crack height, the greater the axial critical compressive stress. The correctness of the theory is verified by the results of the 1# model test.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451.5

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