高地温水工高压隧洞BFRP网格增强衬砌的试验研究

发布时间：2018-06-18 07:20

本文选题：水工隧洞 + 高地温　；参考：《广西大学》2017年硕士论文

【摘要】：本文课题来源于国家自然科学基金资助项目"高地温梯度水工高压隧洞THM耦合作用下的承载特性研究(项目编号:51369007)",针对高地温、高内水压力情况下水工隧洞常规混凝土衬砌在衬砌内外壁间高温度梯度和高内水压力联合作用下拉应力迭加导致衬砌严重开裂的工程问题,在衬砌结构厚壁圆筒模型的结构应力分析的基础上,本文开展了混凝土衬砌的玄武岩纤维增强树脂复合材料(BFRP:Basalt Fiber Reinforced Polymer)网格增强技术的水工结构模型试验,试验中进行了声发射监测与应变的监测,并开展了常规混凝土衬砌的对比试验。主要研究结论如下:(1)弹性力学分析结果表明,高地温水工高压隧洞在弹性工作阶段的承载能力主要受控于温度荷载和内水压力作用下的迭加拉应力。在产生相同拉应力的条件下,温度梯度荷载与内水压力荷载之间存在明确的线性转换关系。因此,在水工隧洞模型试验的加载过程中,采用一定内水压力模拟设定温度荷载的拉应力效应的简化加载方法是可行的,有利于降低模型试验加载的技术难度。(2)试验研究表明,与常规混凝土衬砌结构相比较,在衬砌内、外壁分别布设BFRP网格的混凝土衬砌结构的弹性工作阶段极限承载力提高了 21%,主宏观裂缝最大开度减小了 68%,宏观裂缝空间分布更为分散。(3)试验研究表明,与常规混凝土衬砌结构相比较,BFRP网格增强衬砌结构的开裂前内壁环向拉应变增大了 81%,开裂时的声发射绝对能量占加载过程中声发射总累积绝对能量的33.78%(前者为99.38%)。由此说明,常规混凝土衬砌结构的主要破坏模式为脆性破坏,而BFRP网格增强衬砌结构的主要破坏模式为延性破坏。BFRP网格的增强效应来源于其所具有的良好抗拉和拉变形性能,从而有利于衬砌结构整体承载能力的充分发挥。
[Abstract]:This paper comes from the research on the bearing characteristics of THM coupling in high geothermal gradient hydraulic tunnel (project No.: 51369007), funded by the National Natural Science Foundation of China, and aims at highland temperature. Under the condition of high internal water pressure, the combined action of high temperature gradient and high internal water pressure on the lining of conventional concrete lining of hydraulic tunnel leads to the serious cracking of lining. On the basis of structural stress analysis of thick-walled cylinder model of lining structure, the hydraulic structural model test of BFRP: Basalt Fiber reinforced Polymer mesh reinforcement technique for concrete lining basalt fiber reinforced resin composite has been carried out in this paper. The acoustic emission monitoring and strain monitoring are carried out, and the contrast tests of conventional concrete lining are carried out. The main conclusions are as follows: (1) the results of elastic mechanics analysis show that the bearing capacity of high temperature and high pressure tunnel is mainly controlled by the superimposed tensile stress under the action of temperature load and internal water pressure. Under the condition of the same tensile stress, there is a definite linear transformation relationship between the temperature gradient load and the internal water pressure load. Therefore, in the loading process of hydraulic tunnel model test, it is feasible to use a simplified loading method to simulate the tensile stress effect of a given temperature load under certain internal water pressure, which is helpful to reduce the technical difficulty of model test loading. In comparison with conventional concrete lining structures, The ultimate bearing capacity of concrete lining structure with BFRP mesh is increased by 21%, the maximum opening of main macroscopic crack is reduced by 68%, and the spatial distribution of macroscopic crack is more dispersed. The experimental research shows that the ultimate bearing capacity of concrete lining structure is increased by 21%, and the maximum opening degree of main macroscopic crack decreases by 68%, and the spatial distribution of macroscopic crack is more dispersed. Compared with conventional concrete lining structure, the internal wall circumferential tension strain of BFRP mesh reinforced lining structure increases by 81% before cracking, and the absolute energy of acoustic emission during cracking accounts for 33.78% of the total cumulative absolute energy of acoustic emission during loading (the former is 99.38%). It shows that the main failure mode of conventional concrete lining structure is brittle failure, while the main failure mode of BFRP mesh reinforced lining structure is ductile failure. The strengthening effect of BFRP mesh originates from its good tensile and tensile deformation properties. Therefore, it is advantageous to give full play to the overall bearing capacity of lining structure.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV554

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