白垩系岩层冻融损伤破坏及可注性实验研究

发布时间：2018-03-13 01:23

本文选题：白垩系砂岩　切入点：冻融　出处：《西安科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,西北地区矿井建设中,多数井筒需要穿过白垩系、侏罗系巨厚岩层,该岩层具有含水量大、岩性松软等特点,普通凿井法难以通过,多采用冻结法或普通法结合工作面预注浆施工。部分冻结法施工井筒冻结壁解冻后出现井壁、马头门涌水现象,导致井筒施工工期长,水治理费用高等问题。白垩系、侏罗系岩层含水多为孔隙裂隙水,岩层孔隙率大,普通浆液难以注入,注浆防水减渗效果差,普通法结合工作面预注浆施工难。另外由于针对冻融作用下软岩物理力学性质研究成果的缺失,特别是软岩冻结解冻后的物理力学参数的缺失,导致西部地区冻结法施工井筒井壁设计缺乏科学性。以上问题已成为影响西部地区矿井安全、科学施工和急需解决的技术难题。针对上述工程技术问题,以新庄煤矿风立井井筒建设为工程背景,以室内试验为基础,分析了粗粒砂岩、中粒砂岩、泥岩未冻前、冻结后以及解冻后的物理力学性质变化,探讨冻融对岩体的损伤;对冻结前、冻融作用后粗粒砂岩和中粒砂岩的孔隙比表面积、孔容、孔径分布等参数进行测试,从微观角度分析冻融对岩石内部孔隙裂隙结构的影响;开展了孔隙裂隙砂岩不同注浆材料、注浆压力下的可注性研究;同时探讨软岩冻结井筒成井后的水害问题,并对壁后注浆提出合理的建议。主要研究结论有:(1)分别对粗粒砂岩、中粒砂岩、泥岩开展常温、冻结(-30℃)和解冻后三种状态下的单轴压缩试验。试验结果表明:(1)三种饱和岩石在三种状态下所得应力-应变曲线形状是一致的,都经历了压密阶段、弹性增长阶段、塑性屈服阶段和破坏四个阶段,其中破坏形式主要是岩石内部受拉伸破坏为主。(2)三种状态下,岩石强度都有不同程度变化,冻结状态强度最大、常温次之、解冻后岩石强度最小,一次冻融循环对粗砂岩单轴抗压强度影响明显,对中砂岩和泥岩影响小。(3)经过一次冻融循环后,三种岩石弹性模量都减小,不同岩石减小程度不同。(4)一次冻融循环对粗砂岩饱和吸水率敏感,其内部结构受冻融引起的损伤大,对中砂岩和泥岩饱和吸水率影响不大,对其内部结构损伤较小。(2)粗粒砂岩和中粒砂岩冻融前后微观结构分析及岩样表面微观扫描分析试验结果表明:饱和粗粒砂岩和中粒砂岩在冻融前后微观结构发生显著变化,其中粗砂岩比表面积和孔容都有增加,但是平均孔径减小;中粒砂岩比表面积增加而孔容和平均孔径都减小,两种岩石的吸水率、大小孔隙率不同,增加幅度也不相同。(3)运用自主设计加工的岩石渗透系数测试和注浆实验装置,选取超细水泥和脲醛树脂两种浆液,进行重复注浆,测量每次注浆前后岩石试件的渗透系数,对测量结果进行对比分析,研究粗粒砂岩不同注浆材料、注浆压力下的可注性,试验结果表明:(1)脲醛树脂化学浆液初凝时间随着草酸溶液浓度增大而减少,减少幅度随着草酸溶液浓度增加而降低。(2)渗透系数随着注浆次数的增加而减小,注浆防渗效果显著。(3)对颗粒型材料无法注入的孔隙裂隙砂岩,化学浆液能够起到良好的效果。
[Abstract]:At present, the mine construction in Northwest China, most of the shafts need to pass through the Cretaceous, Jurassic thick strata, the strata with large water content, loose lithology characteristics, common drilling method to the freezing method or common law combined with the working face pre grouting construction. Part of freezing method construction of shaft frozen wall thawing after lining horsehead, water gushing phenomenon, the shaft long construction period, high water treatment cost. The Cretaceous, Jurassic strata water is pore fissure water, rock porosity, general difficult to inject slurry, grouting waterproofing infiltration reduction effect is poor, working face pre grouting construction combined with the common law difficult. Also due to the lack of research results for freezing properties the physical mechanics of soft rock and thawing, especially lack of physical and mechanical parameters of soft rock freezing thawing, leading to the western region design and construction method of freezing shaft wall is lack of science. The problem has become the influence of mine safety in western areas, scientific construction and technical problems needed to be solved. According to the above engineering problems in Xinzhuang coal mine wind shaft construction as the engineering background, based on experiments, analysis of coarse sandstone, sandstone, mudstone and unfrozen before and after freezing and thawing mechanics change in the nature of freeze-thaw damage of rock mass; on the freezing before freezing and thawing after coarse sandstone and sandstone pore surface area, pore size distribution of Kong Rong, were tested, from the micro perspective analysis of freeze-thaw effect on internal pore structure of the rock; the fractured sandstone with different grouting study of grouting material, injection pressure; and to explore the soft rock freezing shaft into the water problem well, and put forward reasonable suggestions on grouting. The main conclusions are as follows: (1) respectively for coarse grained sandstone in grain Sandstone, mudstone in normal temperature, freezing and thawing (-30 C) after three under the condition of uniaxial compression test. Test results show that: (1) three kinds of saturated rock income in the three states of stress - strain curve shape is consistent, have experienced the compression phase, elastic plastic growth stage. The yield stage and the four stages of damage, including the destruction is the main form of rock tensile failure. (2) under the three conditions of rock strength have different degrees of change, freezing intensity, temperature of post thaw rock strength minimum, one freeze-thaw cycle effect on uniaxial compressive strength the coarse sandstone, little influence on in sandstone and mudstone. (3) after one freeze-thaw cycle, three kinds of rock elastic modulus decreased, different rock decreased in different degree. (4) one freeze-thaw cycle of sand rock saturated water absorption rate sensitive, the internal structure of the freeze-thaw damage caused by large, on In the sandstone and mudstone saturated water absorption rate has little effect on its internal structure damage is smaller. (2) coarse sandstone and sandstone before and after freeze-thaw and microstructure of rock surface micro scanning analysis test results show that the saturated coarse sandstone and sandstone before and after freeze-thaw in micro structure changed significantly, including coarse sand rock pore volume and specific surface area are increased, but the average pore size decreases; sandstone pore volume and average pore size increased and the specific surface area decreases, the water absorption rate of two kinds of rocks with different porosity, size, the increase is not the same. (3) transport coefficient test and grouting experiment device independent design and processing the rock permeability, selection of superfine cement and urea formaldehyde resin two slurry, were measured before and after each repeated grouting, grouting rock permeability coefficient of specimen, the comparative analysis of the measurement results of coarse sandstone with different grouting materials, grouting Under the pressure of grouting, test results show that: (1) urea formaldehyde resin chemical grout initial setting time with oxalic acid solution concentration decreases, reduce the rate decreased with increasing concentration of the oxalic acid solution. (2) the permeability coefficient decreases with the increase of the number of grouting, grouting anti-seepage effect significantly. (3) pore fissure the sandstone particle material not injected, chemical grout can play a good effect.

【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD265

【相似文献】