软土增强固化机理与固化土的性能研究和应用

发布时间：2018-03-05 22:37

本文选题：固化土　切入点：水泥土　出处：《安徽理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：在如今的工程中,我们一般采用水泥搅拌桩作为桩基础,然而实践中发现,当工程中遇到了高含水量而且含有机质的淤泥质土时,水泥搅拌桩往往会出现强度偏低,难以成桩的情况,而且处理成本却很高,因此有必要选择新型固化剂代替传统水泥。本文主要阐述了软土增强固化剂的研究现状和展望,分析了新型固化剂对土壤的固化机理,将传统水泥和固化剂相比较。实验过程中,室内实验我们采用水泥和固化剂掺量分别为10%、15%、20%,水灰比为1.0、1.5、2.0,分别测其固化土的无侧限抗压强度。实验结果表明,固化土强度随着固化剂的掺量增加而增加,然而固化土强度增加速率有所减低,但其强度增加的速率远远大于水泥[1]。而水灰比却随着水灰比的的增大,其固化土的强度减小。现场实验是在上海嘉定区打的旋喷桩,水泥和软土固化剂的水灰比都选取0.7、1.0,而掺量分别为10%、15%、20%,通过测定取芯的强度对比,得出以下结论:(1)对于旋喷桩实验,软土增强固化剂的固化效果明显优于P.042.5号水泥。(2)通过实验表明,对于含砂的土层,软土增强固化剂固化土强度明显高于其他土层。现场试验结果表明,软土增强固化剂固化土的取芯强度是水泥土的1.82~2.38倍,施工性能较好,浆液无离析,现场无堵管等。(3)用软土增强固化剂对软土地基进行处理,特别是对高含水量和富含有机质的软土,比普通水泥加固效果要好[42]。用固化剂对浅层地基处理时,我们往往可就地取材,节省大量水泥砂石料费用,与一些混凝材料相比,一般可以使材料费降到20%~30%,因此值得推广应用。通过室内试验和现场实验证明,用软土增强固化剂对软土地基进行处理,特别是对高含水量和富含有机质的软土,比普通水泥加固效果要好。用固化剂对浅层地基处理时,我们往往可就地取材,节省大量水泥砂石料费用,与一些混凝材料相比,一般可以使材料费降20%~30%,因此值得推广应用[2]。(1)软土增强固化剂固化土中钙矾石含量相对较高,增加固化土水含量,提高了固化土的早期强度;(2)随着软土增强固化剂掺量的增加,固化土强度增加速率有所减低,但其强度增加的速率远远大于水泥;(3)软土增强固化剂固化淤泥土,室内试验强度是水泥土的1.83~2.78倍,取芯强度是水泥土的1.82~2.38倍,对含砂高粘土有较好的固化效果。
[Abstract]:In today's projects, we usually use cement mixing pile as pile foundation. However, it is found in practice that the strength of cement mixing pile is low when the silt soil with high water content and organic matter is encountered in the project. It is necessary to choose new curing agent instead of traditional cement because it is difficult to form pile, and the treatment cost is very high. This paper mainly describes the research status and prospect of soft soil reinforcement curing agent, and analyzes the mechanism of the new curing agent to soil. Comparing the traditional cement with the curing agent, in the laboratory experiment, the content of cement and curing agent is 10151520 and the ratio of water to cement is 1.0 ~ 1.5 / 2.0. The unconfined compressive strength of the solidified soil is measured respectively. The strength of solidified soil increases with the increase of the content of curing agent, but the increasing rate of strength of solidified soil decreases, but the increasing rate of strength of solidified soil is far greater than that of cement [1]. However, the water-cement ratio increases with the increase of water-cement ratio. The strength of the solidified soil is reduced. The field test is based on the rotary jet pile in Jiading District of Shanghai. The cement and soft soil curing agent's water-cement ratio is chosen as 0.71.0, while the content of cement is 100.15% and 20%, respectively. By comparing the strength of the core, the following conclusion: 1) for the rotary jet pile experiment, The solidification effect of soft soil reinforced curing agent is obviously better than that of P.042.5 cement. Through experiment, it is shown that for sandy soil layer, the strength of soft soil reinforced curing agent is obviously higher than that of other soil layers. The field test results show that the solidification strength of soft soil reinforcement hardener is obviously higher than that of other soil layers. The coring strength of solidified soil reinforced with soft soil is 1.822 / 2.38 times of that of cement soil, and the construction performance is better, the slurry is not segregated, and there is no plugging pipe in the field, etc.) the soft soil strengthening and curing agent is used to treat the soft soil foundation. Especially for soft soil with high water content and rich in organic matter, it is better than ordinary cement to reinforce the shallow foundation. When treating shallow foundation with curing agent, we can often use local materials, save a lot of cost of cement sand and stone, and compare with some coagulant. In general, the cost of materials can be reduced to 20% and 30%, so it is worth popularizing and applying. Through laboratory and field experiments, it has been proved that soft soil foundation is treated with soft soil reinforcement and curing agent, especially for soft soil with high water content and rich in organic matter. When treating shallow foundation with curing agent, we can often use local materials to save a lot of cost of cement sand and stone, compared with some coagulant, In general, the cost of materials can be reduced by 20% and 30%, so it is worth popularizing and applying [2]. 1) the content of ettringite in the solidified soil is relatively high, the water content of the solidified soil is increased, and the early strength of the solidified soil is increased with the increase of the content of the reinforced curing agent in the soft soil. The increasing rate of strength of solidified soil is decreased, but the increasing rate of strength of solidified soil is much higher than that of cement-soil (3)) the strength of laboratory test is 1.83 times of that of cement-soil, and the core strength is 1.82 ~ 2.38 times of that of cement-soil. It has good curing effect on high sand clay.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU472

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