【作者】 闫宁霞；

【导师】 王正中；

【作者基本信息】 西北农林科技大学 ， 农业工程， 2006， 硕士

【摘要】 土壤固化剂是一种在常温下能将土壤颗粒黏结并与颗粒中的铝硅酸盐矿物发生化学反应生成胶凝物质的新型建筑材料,它以自然土体为固结对象,具有就地取材、减少砂石用量、无环境污染、造价低廉等优点,在技术和经济上都具有重要意义,世界上许多国家已在各类工程中得以应用,具有广阔的应用前景。本文针对固化土作为渠道衬砌材料存在的强度低、易开裂、抗渗抗冻能力差等急待解决的问题,参考钢纤维混凝土中钢纤维的加筋机理,提出将随机分布的聚丙烯纤维掺入固化土,利用纤维的桥接加筋作用提高固化土的强度和耐久性,利用数理统计、试验设计方法的成果,研究土壤固化剂的土质适应性,纤维固化土的无侧限抗压强度、耐久性以及固化土施工技术参数,得出如下主要结论:(1)固化剂掺量是影响固化土强度、渗透性和的抗冻性的重要因素。同配比条件下,固化土的强度高于水泥土,抗渗性大于水泥土。在纤维掺量为0.9 kg/m3条件下,对于选定的土壤,固化剂用量并非越多越好,固化剂用量以掺入比为1:8较好。(2)当固化剂用量一定时,掺用聚丙烯纤维可显著提高固化土的抗压强度。对试验所用的杨凌黄土,当纤维掺量为0～0.9kg/m3时,固化土强度不断增大;当纤维掺量为0.9～1.5kg/m3时,固化土强度随着纤维掺量的增大而逐渐减小;掺用0.9kg/m3聚丙烯纤维时,固化土的强度达到最高,较不掺纤维的同配比固化土提高了29%。(3)掺用聚丙烯纤维可显著提高固化土抗渗性。对选定的杨凌黄土,当纤维掺量为0.5kg/m3～0.9kg/m3时,固化土渗透系数达到最小,与不掺纤维的固化土相比,在此掺量范围内其渗透系数最小降低27%以上。(4)掺入聚丙烯纤维对固化土的抗冻性有明显的帮助作用。当固化剂掺量为1:8的条件下,纤维掺量为0.9 kg/m3时固化土的抗冻效果最好。(5)压实系数是影响固化土强度和耐久性的主要因素,压实系数越大,固化土抗压强度越高,压实系数对固化土掺入比小的固化土的影响更为显著。试验结果表明,压实系数应在0.9以上,综合考虑经济效益和工程效益,建议固化土压实系数取0.95。(6)养护制度也是影响固化土抗压强度的很重要的因素,不同的养护制度下抗压强度有明显的差异,其中以覆盖塑料薄膜养护28d时的强度最高。更多还原

【Abstract】 Soil stabilizer is one of new building materials, which can felt face of soil grains and make chemical reaction with aluminum-silicate minerals forming gum materials. Because its stabilized object is natural soil, this method have many advantages such as using local materials、reducing sand masses、no environmental pollution and saving engineering costs ,for it having important significance in technology and economy, Many countries all over the world have applied it in many kinds of engineering and its potential will be widely.Focusing on the urgently-solving problems existing on solidified soil used as a canal liner material, such as its low-strength、easily-cracking、bad impermeability and frozen–resistance and so on., analogized with effects of steel fiber in Steel Fiber Reinforced Concrete (SFRC),the paper advanced a new method that mixed random distributing polypropylene fiber into solidified soil. The strength and durability of solidified soil would be improved owing to fiber’s bridging and reinforcing effects. According to achievements in the fields of mathematical statistics and experiment design, we researched soil adaptability ,unconfined compressive strength and durability,construction technique parameters of fiber solidified soil, and finally reached following conclusions:(1)The stabilizer amount is an important factor effecting strength and durability of solidified soil. In the same mixing ratio, its strength higher than cement-stabilized soil but seepage coefficient lower. In condition of 0.9kg/m3 fiber amount, for chosen soil 1:8 stabilizer amount is optimum.(2)When stabilizer amount fixed, mixing polypropylene fiber into solidified soil would increase its compressive strength. For Yangling soil used in experiments, when fiber amount is 0~0.9kg/m3 , compressive strength of solidified soil become higher and higher; when fiber amount is 0.9~1.5kg/m3 , strength reduces with fiber amount increasing; 0.9kg/m3 fiber amount produced the highest compressive strength, higher 29 % than solidified soil with no polypropylene fiber.( 3 ) Mixing polypropylene fiber into solidified soil can remarkably increase impermeability of solidified soil. For the chosen Yangling soil, fiber amount of 0.5~0.9kg/m3 produced the lowest seepage coefficient, lower 27 % than solidified soil with no polypropylene fiber.(4)Mixing polypropylene fiber into solidified soil would be evidently helpful in increasing its frozen -resistance, and reach the best in the condition of 1:8 stabilizer amount and 0.9 kg/m3 fiber amount.(5)Compressive coefficient is a major factor effecting strength and durability of solidified soil. The greater of compressive coefficient, the higher of strength, and it has more remarkable influence on solidified soil with lower mixing ratio. The experimental results indicate that compressive coefficient should be above 0.9. Considering economic benefits and project benefits, it is suggested that compressive coefficient is 0.95.(6)Curing method is also an important factor effecting strength of solidified soil. It has distinct distinguish in strength under different curing methods, of which we obtain the highest compressive strength in covering plastic membrane curing.更多还原