本文關(guān)鍵詞：凍融循環(huán)下鎮(zhèn)賚地區(qū)非飽和鹽漬土及石灰固化土的力學(xué)特性及機(jī)理研究　出處：《吉林大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 碳酸鹽漬土 力學(xué)強(qiáng)度 基質(zhì)吸力 機(jī)理分析 損傷模型

【摘要】：土壤鹽漬化對工程建設(shè)、人類活動、經(jīng)濟(jì)發(fā)展等存在一定的威脅。吉林省鎮(zhèn)賚縣處于吉林省西部地區(qū),該地區(qū)分布大量碳酸鹽漬土,同時(shí)為典型的季凍土區(qū)。鹽漬土中含有一定量的易溶鹽,當(dāng)含水率較低時(shí),會有部分易溶鹽飽和析出,以晶體的形式存在,當(dāng)含水率逐漸升高時(shí),易溶鹽完全溶解于孔隙水中,會造成結(jié)構(gòu)的破壞,降低土體的強(qiáng)度,因此鹽漬土受含水率、含鹽量等條件的影響極大。鎮(zhèn)賚縣冬季寒冷,夏季炎熱,凍融循環(huán)會逐漸改變土體的內(nèi)部結(jié)構(gòu)而影響土體的強(qiáng)度。因此,有必要對鎮(zhèn)賚地區(qū)鹽漬土進(jìn)行不同含水率、含鹽量、凍融循環(huán)次數(shù)下的力學(xué)強(qiáng)度研究。同時(shí),由于鹽漬土易吸收外界的水分而不易消散,大大降低土體的強(qiáng)度,需對鹽漬土進(jìn)行改良。本文結(jié)合國家自然科學(xué)基金項(xiàng)目:“寒旱區(qū)土體鹽漬化HTSM多場耦合地質(zhì)環(huán)境系統(tǒng)災(zāi)變演化機(jī)理與工程效應(yīng)研究”(NO.41430642),“松嫩平原分散土成因機(jī)制及水熱鹽耦合離子遷移模型研究”(N0.41372267),以鎮(zhèn)賚地區(qū)鹽漬土為研究對象,首先研究了鹽漬土在不同含水率、含鹽量及凍融循環(huán)次數(shù)下的無側(cè)限抗壓強(qiáng)度及抗剪強(qiáng)度的變化規(guī)律,但考慮到夏季多雨條件下鹽漬土強(qiáng)度無法滿足工程建設(shè)的需要,采用性價(jià)比較高的石灰進(jìn)行改良,研究了石灰固化鹽漬土在不同石灰摻量、養(yǎng)護(hù)齡期及凍融循環(huán)次數(shù)下的無側(cè)限抗壓強(qiáng)度及抗剪強(qiáng)度的變化規(guī)律。同時(shí)考慮到鹽漬土為非飽和土,利用濾紙法對各影響因素下的鹽漬土進(jìn)行了基質(zhì)吸力的量測,并分別建立了基質(zhì)吸力與無側(cè)限抗壓強(qiáng)度及抗剪強(qiáng)度的關(guān)系式,為從機(jī)理上研究鹽漬土及石灰固化鹽漬土的力學(xué)性質(zhì)提供了一定的依據(jù)。然后利用壓汞法研究了鹽漬土及石灰固化鹽漬土的孔隙分布特征,并利用掃描電鏡對微觀結(jié)構(gòu)進(jìn)行了定性分析及定量分析,從微觀角度解釋了鹽漬土及石灰固化鹽漬土的變化規(guī)律。綜合力學(xué)試驗(yàn)、非飽和基質(zhì)吸力試驗(yàn)及微觀試驗(yàn),以宏觀微觀相結(jié)合的形式討論了鹽漬土及石灰固化鹽漬土的變化機(jī)理。最后基于損傷理論,利用Weibull函數(shù)建立了鹽潰土的損傷本構(gòu)模型。在此基礎(chǔ)上,將凍融循環(huán)次數(shù)考慮進(jìn)模型中,建立了鎮(zhèn)賚地區(qū)考慮凍融循環(huán)次數(shù)的損傷模型。論文共分8章,第1章為緒論,主要介紹選題依據(jù)、研究意義、國內(nèi)外研究現(xiàn)狀、文章的主要內(nèi)容及技術(shù)路線、主要?jiǎng)?chuàng)新點(diǎn)等內(nèi)容。第2章主要研究了結(jié)構(gòu)性、含水率、含鹽量、凍融循環(huán)次數(shù)對鎮(zhèn)賚地區(qū)鹽漬土無側(cè)限抗壓強(qiáng)度的影響及石灰摻量、養(yǎng)護(hù)齡期、凍融循環(huán)次數(shù)對石灰固化鹽漬土無側(cè)限抗壓強(qiáng)度的影響。第3章主要研究了結(jié)構(gòu)性、含水率、含鹽量、凍融循環(huán)次數(shù)對鎮(zhèn)賚地區(qū)鹽漬土抗剪強(qiáng)度的影響及石灰摻量、養(yǎng)護(hù)齡期、凍融循環(huán)次數(shù)對固化鹽漬土抗剪強(qiáng)度的影響。第4章主要研究了基質(zhì)吸力與各影響因素的關(guān)系,同時(shí)建立了基質(zhì)吸力與無側(cè)限抗壓強(qiáng)度、抗剪強(qiáng)度的關(guān)系式。第5章通過壓汞試驗(yàn)及電鏡試驗(yàn)研究了鹽漬土的微觀特性。第6章從機(jī)理上分析了鹽漬土及石灰固化鹽漬土的強(qiáng)度變化。第7章建立了鹽漬土的彈塑性損傷模型。第8章為結(jié)論及建議,總結(jié)了文章的研究成果,并提出了下一步的計(jì)劃。
[Abstract]:Soil salinization of engineering construction, human activities, economic development has certain threat. Jilin County of Zhenlai province in the western region of Jilin Province, the extensive distribution of saline alkali soil in the area, at the same time as the typical seasonal frozen soil area. The soluble salt containing a certain amount of saline soil, when the moisture content is low, there will be some the soluble salt precipitation, exist in crystal form, when the water content is gradually increased, the soluble salt is completely dissolved in the pore water will cause structural damage, reduce the strength of the soil, so the saline soil moisture content, effect of salinity conditions greatly. The cold, hot summer cold in winter in Zhenlai county. Thaw cycle will gradually change the internal structure of soil and affect the strength of soil. Therefore, it is necessary to saline soil in Zhenlai area of different water content, salt content, freezing and thawing cycles on the mechanical strength of the saline soil. At the same time, because of easy to absorb The water is not easy to dissipate, greatly reduce the strength of the soil, necessary to improve saline soil. Combined with the National Natural Science Foundation Project: "soil salinization in cold and arid regions HTSM multi field coupling effect mechanism and engineering geological environment disaster evolution system research" (NO.41430642), "Research on migration model and formation mechanism of soil water and heat dispersion salt ion coupling in the Songnen Plain" (N0.41372267), the saline soil in Zhenlai area as the research object, firstly study the saline soil under different moisture content, variation of unconfined compressive strength and shear strength of the salt content and freeze-thaw cycles under, but considering the strength of salinized soil conditions can not meet the rainy summer the needs of engineering construction, the ratio of higher lime improved on solidified soil lime in different amount of lime, the unconfined compressive strength of curing time and freeze-thaw cycles under And the shear strength changes. At the same time taking into account the saline soil in unsaturated soil, saline soil by using filter paper method and influencing factors of the measurement of matrix suction, and establishes a suction and no relation of compressive strength and shear strength, provides a certain basis for mechanics study on the properties of solidified saline soil in saline soil and lime in mechanism. Then the pore distribution characteristics of solidified saline soil in saline soil and lime mercury pressure method, and the microstructure was analyzed by scanning electron microscopy and quantitative qualitative analysis, explained the variation of solidified saline soil and lime saline soil from microcosmic angle. Mechanical test, matrix suction of unsaturated test and microstructure test, by combining the macroscopic and microcosmic form discussed the change mechanism of solidified saline soil in saline soil and lime. Finally, based on the damage theory, the use of Weibull The function of the establishment of salinized soil damage constitutive model. On this basis, the number of freeze-thaw cycles into the model, the establishment of the Zhenlai area with freezing thawing cycles injury model. The thesis consists of 8 chapters, the first chapter is the introduction, mainly introduces the background, research significance, research status at home and abroad, mainly the contents of the article and technical route, the main innovation points. The second chapter mainly study the structure, moisture content, salt content, freeze-thaw cycles, unconfined compressive strength and the influence of lime content on saline soil in Zhenlai area, curing period, freeze-thaw cycles the impact of unconfined compressive strength the lime solidified soil. The third chapter mainly study the structure, moisture content, salt content, freeze-thaw cycles and the impact strength of lime dosage on shear of saline soil in Zhenlai area, curing period, effect of freeze-thaw cycles on shear strength of solidified soil. The fourth chapter mainly studies the matrix suction and the influence factors, and establish the matric suction and the unconfined compressive strength, anti shear strength. The relation between the microscopic characteristics of the fifth chapter of saline soil was investigated by mercury injection test and SEM test. The sixth chapter analyzes the change of strength of solidified saline soil in saline soil and lime. From the mechanism. The seventh chapter establishes saline soil elastoplastic damage model. The eighth chapter is the conclusion and suggestion, summarizes the research results of the article, and put forward the next step of the plan.

【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TU44
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本文編號：1360357