【摘要】：非飽和土中水分的遷移主要是在基質(zhì)勢(shì)和重力勢(shì)的共同驅(qū)動(dòng)下產(chǎn)生的。受毛細(xì)上升作用的影響,潮濕土遺址中發(fā)生水分運(yùn)移及含水率波動(dòng),導(dǎo)致一系列干縮開裂、鹽害等問題,促進(jìn)土遺址的劣化。本論文研究直流電場控制毛細(xì)水上升的學(xué)術(shù)機(jī)理,探討向土體施加直流電場抑制潮濕土遺址中毛細(xì)水上升的可行性。本論文從非飽和土中能量狀態(tài)分析出發(fā),基于非飽和達(dá)西定律、歐姆定律、電荷守恒定律以及質(zhì)量守恒定律,建立了描述非飽和土在直流電場作用下的水分分布的理論模型,并具體討論了模型中涉所及的參數(shù)(如土體電導(dǎo)率、基質(zhì)吸力以及非飽和滲透系數(shù))與含水率的關(guān)系。利用室內(nèi)的直流電場抑制毛細(xì)水上升試驗(yàn)數(shù)據(jù),檢驗(yàn)了直流電場作用下的水分分布理論模型的可靠性。測定土水特征曲線、土體的非飽和滲透系數(shù),獲得理論模型所包含的參數(shù);以具體試驗(yàn)情況為基礎(chǔ),設(shè)定初始條件和邊界條件,實(shí)現(xiàn)理論計(jì)算結(jié)果與試驗(yàn)結(jié)果的對(duì)比。本論文闡述了毛細(xì)水與土遺址劣化的關(guān)系,分析了施加直流電場抑制毛細(xì)水上升進(jìn)而保護(hù)土遺址的原理。研究認(rèn)為,土遺址的劣化,不是水分本身造成的,而是在毛細(xì)水作用下含水率的變化及鹽分的運(yùn)移造成的。施加直流電場,能夠通過電勢(shì)來削弱基質(zhì)勢(shì)引起的毛細(xì)水遷移問題。研究發(fā)現(xiàn),直流電場作用下的水分分布的理論模型,理論計(jì)算結(jié)果與試驗(yàn)結(jié)果吻合良好,能夠定量地描述直流電場對(duì)毛細(xì)水運(yùn)移的影響。研究結(jié)果表明,直流電場通過抑制非飽和土中毛細(xì)水運(yùn)移,能夠有效減少遺址土中水分波動(dòng),進(jìn)而減少遺址土濕脹-干縮和鹽分反復(fù)溶解-結(jié)晶,達(dá)到保護(hù)土遺址的目的。
[Abstract]:The migration of water in unsaturated soil is mainly driven by the matrix potential and gravity potential. Under the influence of capillary rising, moisture migration and water content fluctuation occur in moist soil sites, which lead to a series of problems such as dry shrinkage, cracking, salt damage, and promote the deterioration of soil sites. In this paper, the academic mechanism of direct current field controlling capillary water rise is studied, and the feasibility of restraining capillary water rising in moist soil site by applying direct current field to soil is discussed. Based on the analysis of the energy state in unsaturated soil, based on the unsaturated Darcy law, Ohm law, charge conservation law and mass conservation law, a theoretical model is established to describe the water distribution of unsaturated soil under the action of DC electric field. The relationship between soil conductivity, matrix suction and unsaturated permeability coefficient is discussed in detail. The reliability of the theoretical model of water distribution under the action of DC electric field is tested by using the experimental data of the indoor DC field to suppress the rise of capillary water. The characteristic curves of soil and water, the unsaturated permeability coefficient of soil are measured, and the parameters contained in the theoretical model are obtained, and the initial and boundary conditions are set on the basis of specific test cases, and the comparison between the theoretical calculation results and the experimental results is realized. In this paper, the relationship between capillary water and soil site deterioration is discussed, and the principle of applying direct current field to restrain capillary water rising and protect earth site is analyzed. It is concluded that the deterioration of earth sites is not caused by water itself, but by the change of water content and the movement of salt under the action of capillary water. The application of DC electric field can weaken the capillary water migration caused by matrix potential. It is found that the theoretical model of water distribution under the action of DC electric field is in good agreement with the experimental results, and the effect of DC field on capillary water transport can be quantitatively described. The results show that the direct current electric field can effectively reduce the fluctuation of water in the soil by restraining the capillary water migration in unsaturated soil, and then reduce the swelling and drying shrinkage of the soil and the repeated dissolution and crystallization of salt to protect the soil site.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TU43

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 張虎元;蓋玉璽;朱世彬;生雨萌;;直流電場抑制潮濕土遺址毛細(xì)水上升試驗(yàn)研究[J];蘭州大學(xué)學(xué)報(bào)(自然科學(xué)版);2016年05期

2 歐陽斌強(qiáng);唐朝生;王德銀;徐士康;施斌;;土體水分蒸發(fā)研究進(jìn)展[J];巖土力學(xué);2016年03期

3 胡冉;陳益峰;周創(chuàng)兵;;基于孔隙分布的變形土土水特征曲線模型[J];巖土工程學(xué)報(bào);2013年08期

4 王旭東;;潮濕環(huán)境土遺址保護(hù)理念探索與保護(hù)技術(shù)展望[J];敦煌研究;2013年01期

5 王柳江;劉斯宏;汪俊波;朱豪;;電場-滲流場-應(yīng)力場耦合的電滲固結(jié)數(shù)值分析[J];巖土力學(xué);2012年06期

6 楊強(qiáng)義;李承蔚;;毛細(xì)水干濕循環(huán)對(duì)土遺址風(fēng)化影響的試驗(yàn)研究[J];地下空間與工程學(xué)報(bào);2012年03期

7 張虎元;李敏;王旭東;郭青林;;潮濕土遺址界定及病害分類研究[J];敦煌研究;2011年06期

8 李瑛;龔曉南;;軟黏土地基電滲加固的設(shè)計(jì)方法研究[J];巖土工程學(xué)報(bào);2011年06期

9 胡黎明;吳偉令;吳輝;;軟土地基電滲固結(jié)理論分析與數(shù)值模擬[J];巖土力學(xué);2010年12期

10 李瑛;龔曉南;郭彪;周志剛;;電滲軟黏土電導(dǎo)率特性及其導(dǎo)電機(jī)制研究[J];巖石力學(xué)與工程學(xué)報(bào);2010年S2期

相關(guān)碩士學(xué)位論文 前1條

1 王金濤;基于地貌與第四紀(jì)方法的良渚古城研究[D];華東師范大學(xué);2012年

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