膨脹土膨脹性與收縮性的對比試驗研究
發(fā)布時間：2018-12-18 05:32
【摘要】：膨脹和收縮是膨脹土最為顯著的特性,目前關(guān)于膨脹土脹縮性質(zhì)的聯(lián)系對比研究較少,大部分文獻(xiàn)都是側(cè)重于研究膨脹土的膨脹(或收縮)單方面,此外工程設(shè)計中較多考慮膨脹土的膨脹性質(zhì),而常常忽視收縮性質(zhì)。因此對膨脹土的脹縮機理及兩者間的聯(lián)系對比研究顯得十分必要。結(jié)合理論分析,推導(dǎo)得出膨脹土的膨脹和收縮相關(guān)方程。通過一系列室內(nèi)試驗研究,闡明了膨脹土吸水膨脹和失水收縮過程及與之相關(guān)的一些規(guī)律。最后綜合對比膨脹土膨脹和收縮特性,揭示了兩者之間的內(nèi)在統(tǒng)一性和差異性,且闡述了各自的工程意義。 首先,理論分析部分主要從膨脹(收縮)過程和膨脹(收縮)方程方面進(jìn)行論述。膨脹過程主要包括孔隙填充和顆粒膨脹兩大階段,以“粒間膨脹(雙電層)”和“晶格膨脹”為理論基礎(chǔ)建立了膨脹土理論膨脹方程；收縮過程主要涉及到水分蒸發(fā),水分遷移及裂隙產(chǎn)生等階段,通過對既有收縮曲線分析得出了收縮經(jīng)驗方程,并指出了產(chǎn)生收縮的細(xì)觀層面的動力來源于液橋力,宏觀層面表現(xiàn)為基質(zhì)吸力。 其次,室內(nèi)試驗主要包括基本土工試驗,膨脹試驗和收縮試驗,各試驗均揭示了膨脹土脹縮的相關(guān)規(guī)律。膨脹試驗表明：膨脹土膨脹過程在膨脹時程曲線上可分為快速膨脹,減速膨脹和緩慢膨脹三個階段。試樣最大膨脹率(力)隨著初始含水率的增大而逐漸減小,試樣最大膨脹力隨著初始干密度的增大而逐漸增大。膨脹土吸水膨脹全過程分為“孔隙填充”和“顆粒膨脹”兩個階段,而“顆粒膨脹”又可細(xì)劃為“吸水階段-膨脹階段-穩(wěn)定階段”,并得出了膨脹土吸水膨脹方程。收縮試驗表明：土中水分蒸發(fā)過程在收縮時程曲線上可分為快速蒸發(fā)、減速蒸發(fā)和緩慢蒸發(fā)三個階段,且膨脹土最大線縮率隨著試樣初始含水率的增大而遞增。膨脹土的收縮全過程可分為“快速收縮、減速收縮、殘余收縮”三階段,其中“快速收縮階段”主要是孔隙水的流失,“減速收縮階段”主要是殘留孔隙水和弱結(jié)合水的散失,“殘余收縮階段”主要為水汽擴散。導(dǎo)致土體產(chǎn)生收縮動力為基質(zhì)吸力,試驗測得其最大值近1MPa。室內(nèi)試驗采用成都和濰坊地區(qū)兩種膨脹土進(jìn)行測試,兩種土試驗結(jié)果基本一致。 最后,通過對比膨脹土膨脹和收縮特性,得出兩者之間的統(tǒng)一性在于本質(zhì)上都是由水分變化引起的土體結(jié)構(gòu)的改變,并利用這一觀點得出了膨脹土保濕法的平衡含水量。膨脹土膨脹性和收縮性之間的差異性主要集中于水的狀態(tài)、水的運動方向、土體結(jié)構(gòu)改造和土體強度改變等方面,通過差異性對比可解釋膨脹土邊坡的變形破壞機理。
[Abstract]:Expansion and shrinkage are the most obvious characteristics of expansive soil. At present, there are few relative studies on swelling and shrinkage properties of expansive soil. Most of the literature focuses on the expansion (or contraction) of expansive soil. In addition, the expansive property of expansive soil is considered in engineering design, but the shrinkage property is often neglected. Therefore, it is necessary to study the swelling and shrinkage mechanism of expansive soil and the relationship between them. Based on the theoretical analysis, the expansion and shrinkage equations of expansive soil are derived. Through a series of laboratory experiments, the process of water absorption, water loss and shrinkage of expansive soil and some related laws are expounded. Finally, by comparing the expansion and shrinkage characteristics of expansive soil, the inherent unity and difference between them are revealed, and their engineering significance is expounded. First of all, the theoretical analysis mainly discusses the process of expansion (contraction) and the equation of expansion (contraction). The expansion process mainly includes two stages of pore filling and particle expansion. Based on the theory of "intergranular expansion (double electric layer)" and "lattice expansion", the theoretical expansion equation of expansive soil is established. The shrinkage process is mainly related to the stages of water evaporation, water migration and the formation of cracks. Through the analysis of the existing shrinkage curves, the shrinkage empirical equation is obtained, and it is pointed out that the dynamic force of the meso-plane that produces the shrinkage comes from the liquid bridge force. Macro-level performance for the matrix suction. Secondly, the laboratory tests mainly include basic geotechnical test, expansion test and shrinkage test, and each test reveals the relevant laws of dilatation and shrinkage of expansive soil. The expansion test shows that the swelling process of expansive soil can be divided into three stages: rapid expansion, slow expansion and slow expansion. The maximum expansion rate (force) of the specimen decreases with the increase of the initial moisture content, and the maximum expansion force increases with the increase of the initial dry density. The whole process of water absorption and expansion of expansive soil can be divided into two stages: "pore filling" and "particle expansion", and "particle expansion" can be classified into "water absorption stage, expansion stage-stable stage", and the water absorption expansion equation of expansive soil is obtained. The shrinkage test shows that the process of water evaporation in soil can be divided into three stages: rapid evaporation, deceleration evaporation and slow evaporation, and the maximum linear shrinkage of expansive soil increases with the increase of the initial moisture content of the sample. The whole process of shrinkage of expansive soil can be divided into three stages: rapid shrinkage, deceleration shrinkage and residual shrinkage, in which the "rapid shrinkage stage" is mainly the loss of pore water, and the "deceleration shrinkage stage" is mainly the loss of residual pore water and weakly combined water. The residual contraction stage is mainly water vapor diffusion. The shrinkage force of soil is matrix suction, and the maximum value is about 1 MPA. Two kinds of expansive soils were tested in Chengdu and Weifang, and the results were consistent. Finally, by comparing the expansion and shrinkage characteristics of expansive soil, it is concluded that the unity between the two is essentially the change of soil structure caused by water change, and the equilibrium moisture content of expansive soil is obtained by using this viewpoint. The difference between expansion and shrinkage of expansive soil is mainly focused on the state of water, the direction of water movement, the transformation of soil structure and the change of soil strength, etc. The deformation and failure mechanism of expansive soil slope can be explained by comparing the differences.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU443
本文編號：2385424
[Abstract]:Expansion and shrinkage are the most obvious characteristics of expansive soil. At present, there are few relative studies on swelling and shrinkage properties of expansive soil. Most of the literature focuses on the expansion (or contraction) of expansive soil. In addition, the expansive property of expansive soil is considered in engineering design, but the shrinkage property is often neglected. Therefore, it is necessary to study the swelling and shrinkage mechanism of expansive soil and the relationship between them. Based on the theoretical analysis, the expansion and shrinkage equations of expansive soil are derived. Through a series of laboratory experiments, the process of water absorption, water loss and shrinkage of expansive soil and some related laws are expounded. Finally, by comparing the expansion and shrinkage characteristics of expansive soil, the inherent unity and difference between them are revealed, and their engineering significance is expounded. First of all, the theoretical analysis mainly discusses the process of expansion (contraction) and the equation of expansion (contraction). The expansion process mainly includes two stages of pore filling and particle expansion. Based on the theory of "intergranular expansion (double electric layer)" and "lattice expansion", the theoretical expansion equation of expansive soil is established. The shrinkage process is mainly related to the stages of water evaporation, water migration and the formation of cracks. Through the analysis of the existing shrinkage curves, the shrinkage empirical equation is obtained, and it is pointed out that the dynamic force of the meso-plane that produces the shrinkage comes from the liquid bridge force. Macro-level performance for the matrix suction. Secondly, the laboratory tests mainly include basic geotechnical test, expansion test and shrinkage test, and each test reveals the relevant laws of dilatation and shrinkage of expansive soil. The expansion test shows that the swelling process of expansive soil can be divided into three stages: rapid expansion, slow expansion and slow expansion. The maximum expansion rate (force) of the specimen decreases with the increase of the initial moisture content, and the maximum expansion force increases with the increase of the initial dry density. The whole process of water absorption and expansion of expansive soil can be divided into two stages: "pore filling" and "particle expansion", and "particle expansion" can be classified into "water absorption stage, expansion stage-stable stage", and the water absorption expansion equation of expansive soil is obtained. The shrinkage test shows that the process of water evaporation in soil can be divided into three stages: rapid evaporation, deceleration evaporation and slow evaporation, and the maximum linear shrinkage of expansive soil increases with the increase of the initial moisture content of the sample. The whole process of shrinkage of expansive soil can be divided into three stages: rapid shrinkage, deceleration shrinkage and residual shrinkage, in which the "rapid shrinkage stage" is mainly the loss of pore water, and the "deceleration shrinkage stage" is mainly the loss of residual pore water and weakly combined water. The residual contraction stage is mainly water vapor diffusion. The shrinkage force of soil is matrix suction, and the maximum value is about 1 MPA. Two kinds of expansive soils were tested in Chengdu and Weifang, and the results were consistent. Finally, by comparing the expansion and shrinkage characteristics of expansive soil, it is concluded that the unity between the two is essentially the change of soil structure caused by water change, and the equilibrium moisture content of expansive soil is obtained by using this viewpoint. The difference between expansion and shrinkage of expansive soil is mainly focused on the state of water, the direction of water movement, the transformation of soil structure and the change of soil strength, etc. The deformation and failure mechanism of expansive soil slope can be explained by comparing the differences.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU443
【參考文獻(xiàn)】
相關(guān)期刊論文 前10條
1 張炳慧;滕德賓;高秀芬;張令芹;;分散與聚沉分步法測定自由膨脹率[J];大壩觀測與土工測試;1993年02期
2 繆林昌,仲曉晨,殷宗澤;非飽和膨脹土變形規(guī)律的試驗研究[J];大壩觀測與土工測試;1999年03期
3 黃健敏;段海澎;陳善雄;余飛;;江淮膨脹土自由膨脹率特征[J];工程地質(zhì)學(xué)報;2006年06期
4 唐朝生;施斌;顧凱;;土中水分的蒸發(fā)過程試驗研究[J];工程地質(zhì)學(xué)報;2011年06期
5 鐘仰晉;張柳;;膨脹土脹縮特性試驗研究[J];公路交通科技(應(yīng)用技術(shù)版);2008年02期
6 施斌;唐朝生;王寶軍;姜洪濤;;粘性土在不同溫度下龜裂的發(fā)展及其機理討論[J];高校地質(zhì)學(xué)報;2009年02期
7 唐朝生;施斌;劉春;;膨脹土收縮開裂特性研究[J];工程地質(zhì)學(xué)報;2012年05期
8 查甫生;崔可銳;劉松玉;杜延軍;吳燕開;;膨脹土的循環(huán)脹縮特性試驗研究[J];合肥工業(yè)大學(xué)學(xué)報(自然科學(xué)版);2009年03期
9 徐永福,吳正根,劉傳新;膨脹土的擊實條件與膨脹變形的相關(guān)性研究[J];河海大學(xué)學(xué)報;1997年03期
10 華萱,劉元祚,畢玉蓮,吳遠(yuǎn)航;鈉基膨潤土干燥機理及動力學(xué)模型的研究[J];吉林工學(xué)院學(xué)報;1989年01期
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