高压水作用下井壁混凝土耦合损伤演化机理及强度特征研究

发布时间：2018-01-01 19:06

本文关键词：高压水作用下井壁混凝土耦合损伤演化机理及强度特征研究　出处：《安徽理工大学》2017年博士论文　论文类型：学位论文

【摘要】：煤炭资源开采目前已向深部延伸,新建煤矿井筒穿过含水不稳定地层越来越厚,井壁因此所需承受的地下水压力越来越大;而混凝土作为主要筑壁材料,在高地下水压作用下其损伤演化进程与强度发展问题愈加突出。并且与地面空气环境中的混凝土不同,井壁混凝土长期处于高压水荷载直接作用下,其损伤演化进程和强度特征必将发生变化,这是一个值得研究的问题。因此,论文将充分考虑地下水渗流作用对井壁混凝土应力变形的耦合影响,采用混凝土力学试验、相似模型试验、理论分析、数值计算等研究手段,探究了高压水荷载直接作用下井壁混凝土损伤演化机理以及强度变形特征。针对煤矿立井井筒支护难题,配制出密实度高、抗渗性好的高强高抗渗混凝土作为筑壁材料,并对其在地面空气环境中的主要物理力学性能进行试验研究,可为后续高压水荷载直接作用下井壁混凝土物理力学参数变化提供对比,以及解析解与数值计算参数的选取提供参考。综合考虑水压力大小、水压作用时间、混凝土强度等级三种不同影响因素耦合作用效应,借助SPSS数理统计软件设计出混合正交试验表,开展高压水荷载直接作用下井壁混凝土耦合损伤试验。结果表明对混凝土峰值强度的影响强弱程度依次为水压力大小、混凝土强度等级、水压作用时间。结合声波测试结果、welbull统计分布理论、lemaitre等效应变假设以及损伤力学理论,建立了高压水荷载直接作用下井壁混凝土耦合损伤演化方程,并基于混凝土强度理论推导出相应条件下本构模型。采用岩石三轴试验机开展了高压水荷载直接作用下井壁混凝土水力耦合渗透性试验。结果表明孔隙水在混凝土内部渗流时对其造成的损伤影响较为明显,加速试件的变形破坏;同等条件下孔隙水压越大,井壁混凝土峰值强度及割线弹性模量降低越明显;结合理论分析建立了应力渗流耦合状态下井壁混凝土渗透率演化概念模型。根据养护条件不同将井壁混凝土分为常规、饱和、密封三种状态,开展了高压水荷载直接作用下井壁混凝土强度及变形特征试验研究。发现三种不同状态井壁混凝土都呈现出鲜明的水围压增强效应,密封状态井壁混凝土水围压增强效应明显高于常规和饱和两种状态;高压水荷载直接作用下井壁混凝土强度呈非线性增长,采用Bresler三参数强度破坏准则拟合效果最佳;不同强度等级不同状态井壁混凝土广义峰值轴向应变与水围压呈线性增长关系。基于相似模型理论设计出模型井壁,参照正交试验设计原理将混凝土强度等级、厚径比、配筋率作为影响因素。采用准平面应变加载方式,进行了高压水荷载直接作用下井壁结构模型试验,根据试验结果及正八面体应力空间强度理论建立了相应条件下井壁混凝土强度准则和极限承载力经验公式。基于上述强度准则同时引入高强混凝土脆性损伤因子,在考虑地下水渗流变形耦合影响的基础上进行立井井壁出水机理分析,推导得到了相应条件下立井井壁极限水压力弹塑性解析解,并对其主要影响因素进行了分析比较。基于ABAQUS/CAE应力渗流耦合分析模块,开展了考虑地下水渗流动态耦合影响下井壁与围岩共同作用时应力损伤数值计算,利用USDFLD.for子程序实现了渗透系数与孔隙率的动态耦合分析,结果表明井壁在已发生损伤区域最大主应力与损伤明显区别于传统耦合,为动态耦合完全分析提供了有效途径。
[Abstract]:The exploitation of coal resources has been extended to the deep water, the new mine shaft through Unstable Strata more thick, so the wall needed for groundwater under increasing pressure; and concrete as the main building wall materials, water pressure in the high damage evolution process and the problem is increasingly prominent. The development of strength and different with the ground the air in the environment of concrete, concrete in direct high-pressure water load, the damage evolution process and strength characteristics will be changed, this is a problem worthy of study. Therefore, this paper will fully consider the coupling effect of groundwater seepage on stress and deformation of the concrete wall, the concrete mechanics test, model test theoretical analysis, numerical calculation and other research methods, to explore the direct effect of the high-pressure water load of wall concrete damage evolution mechanism and strength deformation characteristic Sign. In order to solve the problem of coal mine shaft supporting, with high density, high strength and good impermeability and high impermeability concrete as lining material, and the experimental study on the ground in the air environment in the main physical and mechanical performance, can provide comparison of the change of physical mechanical parameters of concrete directly following the high-pressure water load the well wall, and the analytical solution with the numerical parameters of the selected reference. Considering the water pressure, water pressure time, the concrete strength grade of three different factors affecting the coupling effect, using SPSS statistical software to design a hybrid orthogonal test table, carry out the coupling damage test of concrete under direct high-pressure water load. The results show that the influence of concrete strength of the degree of order of peak water pressure, the strength grade of concrete, water pressure time. Combined with the test results of acoustic wave, Welbull The statistical distribution theory, Lemaitre strain hypothesis and the theory of damage mechanics, the damage evolution equation of concrete wall is established directly coupled high-pressure water load, and based on the strength of concrete is deduced under the condition of the corresponding constitutive model. The three axis test carried out rock permeability test of concrete hydraulic coupling under direct high-pressure water load the effect of pore water. The results show that the damage caused to the concrete internal flow is obvious, accelerated deformation destruction; under the same conditions the pore pressure increases, the peak strength and concrete secant elastic modulus decreased more obviously; the concrete permeability coupling seepage force under the evolution of conceptual model with theoretical analysis. According to the different curing conditions will be divided into conventional concrete, saturated, sealing the three state to carry out high-pressure water load directly Experimental study on deformation and strength characteristics of concrete under the action of. Three kinds of concrete shows a sharp water pressure enhancement effect, the sealing state of wall concrete water confining pressure enhancement effect was significantly higher than that of conventional and two saturated state; the high-pressure water load directly under the action of lining concrete strength is nonlinear growth, using the three parameter Bresler the best fitting effect of strength failure criterion; different strength grade of different concrete generalized peak axial strain and confining pressure of water increases linearly. The similar model is designed based on the theory model of wellbore, according to orthogonal design principle of concrete strength, diameter thickness ratio, reinforcement ratio as the influencing factors. The plane strain loading. The wall structure model under direct high-pressure water load test, according to test results and eight sided stress intensity space Theory of experiential formula of the bearing capacity of wall concrete strength criterion and the corresponding limit conditions. The strength criterion based on introducing damage factor of brittleness of concrete, considering the seepage deformation coupling effect analysis on shaft lining water mechanism is deduced under the corresponding condition of shaft lining water pressure limit elastoplastic analysis, and the main influencing factors are analyzed and compared. The ABAQUS/CAE seepage stress coupling analysis module based on the influence of groundwater seepage coupling dynamic interaction under shaft and surrounding rock stress damage numerical calculation, the dynamic coupling coefficient of permeability and porosity analysis using the USDFLD.for subroutine, results show that wall damage in the regional maximum principal stress and the damage is obviously different from the traditional coupling has occurred, and provides an effective way for the dynamic coupling analysis completely.

【学位授予单位】：安徽理工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD352

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