兰州大学机构库 >土木工程与力学学院
SH及石灰加固黄土耐久性试验研究
Alternative TitleExperimental study on durability of SH and lime reinforced loess
任晓峰
Thesis Advisor谌文武
2017-05-30
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword黄土改良 SH材料 石灰 冻融循环 干湿循环
Abstract

中国黄土分布范围广泛,厚度大。大量黄土工程如路基工程、边坡工程、渠道工程等都需要对黄土进行研究改良,使之能达到理想的工程性质,西北地区特殊的地理气候条件使得黄土类构筑物常年经受冻融、干湿等侵袭,这些自然环境因素导致的工程损失亟需改善。目前黄土改良剂有无机类、有机类、离子类和生物酶类四种,其加固效果各有所长。而黄土的改良需要对加固后土体的目的有一个明确要求,而且需要对改良剂的加固效果有正确认识。当单一的固化剂存在自身不足时,可以选择两种性质互补的改良剂进行改良。本文以一种新型有机固化剂SH配合熟石灰进行黄土改良,并对改良后土体的基本强度特征以及在冻融循环、干湿循环条件下的质量、体积、无侧限抗压强度和微观结构变化进行基础研究,研究结果显示:1.固化剂SH及石灰都能使黄土的无侧限抗压强度提高,且石灰对强度提升作用显著;而SH与石灰同时加固时,随着SH浓度增大,不同掺量的石灰对加固土强度的提升能力开始降低,且在SH浓度为1.5%时增长变缓。2.反复冻融循环使得土样试块质量逐渐减少,无侧限抗压强度减小。石灰相比SH,对保持土颗粒骨架完整、降低无侧限抗压强度损失效果更好。当试块中加入SH时,5次冻融循环后强度降低减缓。3.反复干湿循环使得土样试块质量逐渐减小,无侧限抗压强度减小。SH相比石灰,在土体保持孔隙结构完整方面有良好作用,石灰相比SH,对土样强度保持方面效果更好,且掺量越高,强度越大。4.综合各项评价指标,实验结果显示固化剂SH浓度为1.5%及石灰掺量为6%时,试块抗压强度及耐久性能在实际工程用于方面有良好的推广前景。

Other Abstract

Chinese loess distribution is of width and thick, and the stratum of loess is relatively complete. Applied to a large number of loess works, such as roadbed engineering, slope engineering, channel engineering and so on, the loess needs to be studied further and improved, so as to achieve the ideal engineering properties. Due to the special geographical and climatic conditions in the northwest region, many loess structures have been subjected to freezing, thawing and wetting, the damage caused by these natural environmental factors need to be improved.At present, loess improver has inorganic, organic, ionic and biological enzymes four kinds, the reinforcement effect of each has their own strength. Before reinforcement, it must be clear the purpose, and it is necessary to have a correct understanding of the reinforcement effects. When a single curing agent itself is deficient, it is possible to select two kinds of complementary modifiers to improve the loess.In this paper, a new type of organic curing agent SH combined with hydrated lime was used to improve loess, and the basic strength characteristics, quality, volume, unconfined compressive strength and microstructure changes of the improved soil were studied after freeze-thaw and dry-wet cycles, the results show that:1. the curing agent SH and the lime can increase the unconfined compressive strength of the loess respectively. Lime has a significant effect on strength enhancement. When the SH and lime strengthen loess at the same time, with the increase of the SH concentration, the strength of the soil which enhanced by different amount of lime begin to decrease, and the growth slows down when the SH concentration is 1.5%.2. repeated freeze-thaw cycle test makes the quality of soil sample block gradually reduced, unconfined compressive strength decreased. Compared with SH, lime has better effect to keep the integrity of particle skeleton and to reduce the loss of unconfined compressive strength. When the samples were mixed with SH, the strength reduction rate decreased gradually after 5 times of freeze-thaw cycle.3. repeated wet and dry cycle test makes the mass of soil sample block gradually reduced and unconfined compressive strength decreased. Compared with lime, SH has better effect to keep the integrity of soil pore structure. On the contract, lime has better effect on the maintaining of  soil strength. And the higher the dosage, the greater the strength.4. Based on the comprehensive evaluation index, the experimental results show that the compressive strength and durability of the samples show great popularization prospect in practical engineering application. when the concentration of curing agent SH is 1.5% and the lime content is 6%.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226738
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
任晓峰. SH及石灰加固黄土耐久性试验研究[D]. 兰州. 兰州大学,2017.
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