改良黏土作为垃圾填埋场衬里的试验研究

发布时间：2018-06-04 14:48

本文选题：黏性土 + 土壤稳定剂　；参考：《河北建筑工程学院》2017年硕士论文

【摘要】：在垃圾填埋场的建设中,优质的黏性土是垃圾填埋场衬里的重要组成材料,然而由于大量垃圾填埋场的不断建设,尤其在优质黏性土资源贫乏地区,导致优质黏土的供给捉襟见肘。针对张家口现有粉质黏土,利用新材料抗疏力土壤稳定剂进行改良,得到性能更好的黏性土,一方面可以增大库容,另一方面得到更多符合要求的黏性土。配置不同配合比土壤稳定剂,配合比是指土壤稳定剂与所用水的质量比,对能够影响垃圾填埋场安全使用的性质,进行了大量试验研究,试验所用试样的含水率均为最优含水率,主要包括渗透性、无侧限抗压强度、收缩性、膨胀性、水稳性及对离子的吸附性能等试验,旨在改良土体的物理力学特性及环境土工特性,同时得出土壤稳定剂的最优配合比。通过试验结果可以看出,土样的各方面性质有明显改善,其中在配合比为1:100时,最大干密度增大,这对渗透性、收缩性及膨胀性等均有一定的影响;与未改良前相比,渗透系数降低了1-2个数量级,已经大大超过的规范的要求;在各压实度下,线缩率和体缩率均达到了最小;无侧限抗压强度达到最大,同时仍与压实度成正比,养护时间对强度影响不明显;改良土的吸附性能随土壤稳定剂配合比的增大而增强,但吸附量的增长幅度不大;试样的水稳性最佳,而且发生崩解的速率也远远低于其他种类;膨胀率较未改良时有了明显的减小。综合各试验结果,确定了土壤稳定剂的最优配合比为1:100。同时研究了一种将两种改良材料结合到一起的双层衬里结构,上层是利用土壤稳定剂改良的黏性土,主要是利用改良土较高的强度、抗渗性等性能;下层是利用膨润土改良黏性土,主要是利用膨润土改良张家口粉质黏土土较好的吸附性。首先确定了膨润土掺和比对黏性土吸附性的影响,然后对双层结构进行了渗透性、无侧限抗压强度和吸附性能的试验研究,结果表明该结构在保证抗渗性和强度的条件下,吸附性能有明显提高,离子吸附量数倍于单层结构。总而言之,利用土壤稳定剂改良后的土体的物理力学性质和环境土工特性得到了较大的改善,该试验研究对缓解垃圾填埋场所用优质黏土缺乏的问题有重要实际指导意义。
[Abstract]:In the construction of landfill, high quality clay is an important component of landfill lining. However, due to the continuous construction of a large number of landfill sites, especially in areas with poor quality clay resources, As a result, the supply of high quality clay is stretched. According to the existing silty clay in Zhangjiakou, the clay with better performance can be obtained by using the new material anti-thinning soil stabilizer. On the one hand, the reservoir capacity can be increased, on the other hand, more clay can be obtained in accordance with the requirements. The mixture ratio refers to the mass ratio of the soil stabilizer to the water used in the landfill. A large number of experiments have been carried out on the properties that can affect the safe use of the landfill site. The moisture content of the samples used in the test is the optimum moisture content, which mainly includes the tests of permeability, unconfined compressive strength, shrinkage, expansion, water stability and adsorption of ions, etc. The purpose of this paper is to improve the physical and mechanical properties of soil and the environmental geotechnical properties, and to obtain the optimum mixture ratio of soil stabilizers. It can be seen from the test results that the properties of the soil samples have been improved obviously. The maximum dry density increases when the mixing ratio is 1: 100, which has a certain effect on the permeability, shrinkage and expansion of the soil, and compared with that before the improvement. The permeability coefficient has been reduced by 1-2 orders of magnitude, which has greatly exceeded the requirements of the specification. Under each compaction, the linear shrinkage rate and the volume shrinkage rate have reached the minimum; the unconfined compressive strength has reached the maximum, and is still proportional to the compaction degree. The effect of curing time on the strength is not obvious, the adsorption performance of the improved soil increases with the increase of the mixture ratio of soil stabilizer, but the increase of the adsorption capacity is not obvious, the water stability of the sample is the best, and the rate of disintegration is much lower than that of other kinds. The expansion rate decreased obviously compared with that without improvement. According to the experimental results, the optimum mixture ratio of soil stabilizer is 1: 100. At the same time, a double-layer lining structure which combines two kinds of improved materials is studied. The upper layer is clay modified by soil stabilizer, which mainly uses the properties of high strength and impermeability of the improved soil. In the lower layer, bentonite was used to improve clay, and bentonite was used to improve the sorption of Zhangjiakou silty clay. The influence of bentonite blending ratio on the adsorption of clay soil was first determined, and then the permeability, unconfined compressive strength and adsorption performance of the double-layer structure were studied. The results showed that the structure was under the condition of ensuring the impermeability and strength of the structure. The adsorbability of ion is several times as much as that of monolayer structure. In a word, the physical and mechanical properties and the environmental geotechnical properties of the soil modified by soil stabilizer have been greatly improved. The experimental study is of great practical significance in alleviating the lack of high quality clay used in landfills.
【学位授予单位】：河北建筑工程学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU442

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