冻结法凿井冻结孔泥浆置换段抗渗性能研究

发布时间：2018-04-11 07:05

本文选题：冻结法凿井 + 冻结孔　；参考：《中国矿业大学》2017年硕士论文

【摘要】：近年来在西部地区煤矿立井的开凿过程中,广泛使用全深冻结技术穿过软弱的孔隙、裂隙含水岩层。在全深冻结凿井过程中,穿过马头门等井筒附属硐室的冻结孔在解冻后极易形成竖向导水通道,进而威胁整个矿井的安全。泥浆置换充填技术通过在环空中形成水泥结石体环套达到封堵竖向导水通道的目的,但仍有部分冻结孔在开展置换充填后,出现了渗漏水状况,除了可能存在的施工质量问题之外,尚不能排除受冻结冷缩影响,导致的水泥浆结石体充填段的封水性能劣化现象。因而,本文综合采用室内试验、理论分析、模型试验三种研究手段,开展了膨胀型缓凝水泥浆材料,以及泥浆置换充填段的冻融后抗渗性能研究,以便为冻结孔泥浆置换充填材料的选择与优化,乃至泥浆置换充填高度的设计提供依据。首先,通过室内试验研究了外掺UEA、HEA、AEA三种膨胀剂对缓凝水泥浆液工作性能的影响,通过自由膨胀率试验分别得到了三种膨胀剂在不同掺量下水泥砂浆试块的自由膨胀率,验证了膨胀剂的有效性;通过膨胀应力试验得到了原配方中复合外加剂与三种不同掺量的膨胀剂复合使用时试件的膨胀应力随养护龄期的发展规律;通过结石率试验得到了外掺三种不同掺量的膨胀剂对原配方缓凝水泥浆液材料结石率的影响;最后通过缓凝时间试验得到了外掺膨胀剂后缓凝水泥浆液的初凝时间。其次,通过室内试验研究了水泥浆结石体、冻结管界面、围岩界面的抗渗性能,分别得到了膨胀型缓凝水泥浆与非膨胀性缓凝水泥浆液在冻融前后的结石体渗透系数,单位长度的“结石体-围岩界面”、“结石体-冻结管壁界面”的渗透系数,并对采用不同浆液材料时的抗渗性能进行定量分析。然后,通过理论分析的手段,在合理假设的基础上以室内试验结论为基础推导出了泥浆置换段的整体渗透系数以及渗透压、渗流量等水力参数在两界面的分布规律。最后,以室内试验结论和对泥浆置换段抗渗能力的理论分析为基础,对比两种不同的浆液材料,进行了三组相似物理模拟试验,分别得到并比较了冻融工况下,非稳定渗流阶段泥浆置换段上部水头变化对围岩界面渗透压分布规律的影响,稳定渗流阶段围岩界面中的渗流路径上的压力梯度、渗流速度;推导出了稳定渗流阶段围岩界面渗流路径上渗透压与置换段上部水头的关系式;并对原配方缓凝水泥浆液泥浆置换段冻结管界面的抗渗能力进行了定性分析。
[Abstract]:In recent years, in the mining process of coal mine shaft in the western region, the full depth freezing technique is widely used to pass through the weak pore and fissure water-bearing strata.In the process of deep freezing sinking, the freezing hole passing through the auxiliary chamber of the shaft such as Matou Gate is easy to form a vertical guiding water channel after thawing, thus threatening the safety of the whole mine.Mud replacement filling technology can seal the vertical guide water passage by forming cement stone body ring sleeve in the annulus, but there are still some frozen holes that leak after the replacement filling.In addition to the possible construction quality problems, it is not possible to rule out the deterioration of the sealing performance of the cement slurry stone filling section caused by freezing cold shrinkage.Therefore, in this paper, the laboratory test, theoretical analysis and model test are used to study the impermeability of dilated retarded cement slurry and the frozen and thawed filling section.In order to provide the basis for the selection and optimization of the filling materials for the replacement of frozen holes and the design of the filling height for the replacement of the mud.Firstly, the effect of three kinds of expansion agents on the working performance of retarded cement slurry was studied by laboratory test. The free expansion rate of cement mortar was obtained by free expansion test.Through the expansion stress test, the expansion stress of the original formula and three kinds of expansive agent with different amount of expansive agent were obtained by the expansion stress test, and the expansion stress of the specimen was developed with the curing age.The influence of three kinds of expansive agents on the stone rate of the original retarded cement paste was obtained by the calculus rate test, and the initial setting time of the retarded cement slurry after the addition of the expansion agent was obtained by the retarding time test.Secondly, the impermeability of cement slurry stone body, frozen pipe interface and surrounding rock interface is studied through laboratory tests. The permeability coefficient of expansive slow solidified cement slurry and non-expansive retarded cement slurry before and after freeze-thaw is obtained, respectively.The permeability coefficient of "stone body-wall rock interface" and "stone body-frozen pipe wall interface" per unit length is quantitatively analyzed when different slurry materials are used.Then, by means of theoretical analysis and on the basis of reasonable assumptions, the distribution law of hydraulic parameters such as permeability coefficient and hydraulic parameters such as permeability pressure and seepage discharge at the two interfaces are deduced on the basis of the conclusion of laboratory tests.Finally, based on the conclusion of laboratory test and the theoretical analysis of impermeability of mud replacement section, three groups of similar physical simulation tests were carried out by comparing two kinds of different slurry materials, and the results were obtained and compared under freeze-thaw conditions, respectively.The influence of the head change of the upper part of the mud displacement section on the distribution of seepage pressure at the surrounding rock interface in the unstable seepage stage, the pressure gradient and the seepage velocity in the seepage path of the surrounding rock interface in the stable seepage stage;The relationship between the seepage pressure on the seepage path of the surrounding rock interface and the head of the upper displacement section is derived, and the impermeability of the frozen pipe interface of the original formulation retarded cement slurry replacement section is analyzed qualitatively.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD265.3

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