【摘要】：我國是黃土覆蓋面積最大的國家,黃土高原面積達(dá)44萬km2,黃土不但覆蓋面積廣而且厚度大、結(jié)構(gòu)松散、地質(zhì)條件極其不利,其脆弱的地質(zhì)環(huán)境和不當(dāng)?shù)娜祟惞こ袒顒?不當(dāng)?shù)钠麦w開挖和灌溉)、集中的降雨模式,致使該區(qū)域成為我國滑坡地質(zhì)災(zāi)害發(fā)生最為頻繁的區(qū)域。降雨及灌溉入滲是誘發(fā)黃土滑坡的主要因素之一,因此,開展降雨和灌溉條件下水在原狀黃土中的入滲過程具有重要的理論與工程實(shí)際意義。本論文采用室內(nèi)大型原狀土柱試驗(yàn)?zāi)M不同降雨與灌水模式條件,在高度為1米的原狀土柱側(cè)壁埋設(shè)水分計(jì),將水分計(jì)與數(shù)采系統(tǒng)連接,觀測水分入滲中四個(gè)深度黃土體積含水率隨時(shí)間的變化,研究了原狀黃土水分的運(yùn)移規(guī)律,在此基礎(chǔ)上采用HYDRUS——1D數(shù)值模擬方法模擬了水分運(yùn)移過程,對于深入認(rèn)識降雨型和灌溉型黃土滑坡機(jī)理具有重要的科學(xué)意義。研究發(fā)現(xiàn),在雨水沿原狀黃土入滲的過程中,土柱在入滲初期因?yàn)楹时容^低,而基質(zhì)勢又是與含水率相關(guān)的,其梯度較大,因此土柱的入滲能力相對強(qiáng),體積含水率迅速提高。隨著時(shí)間的增長,雨水逐漸進(jìn)入到黃土土柱內(nèi),濕潤峰不斷向前推移,土柱下部黃土的含水率逐漸增高,其與上部黃土之間的基質(zhì)勢梯度逐漸減小,導(dǎo)致土體接受水分的能力逐漸減弱。因此,黃土土坡失去其穩(wěn)定性,是與土體基質(zhì)吸力減小甚至喪失密切相關(guān)的。再次灌溉入滲過程中,由于初始含水率較高,基質(zhì)吸力相對較小,在上部水頭壓力、基質(zhì)吸力及重力作用下,剛開始濕潤鋒的運(yùn)移速率增速很快,當(dāng)水分運(yùn)動至土柱底部時(shí),基質(zhì)勢梯度喪失,最后維持飽和入滲狀態(tài)。土柱入滲試驗(yàn)結(jié)果與HYDRUS-1D數(shù)值模擬結(jié)果間還存在一定的誤差,可能是采用小土樣測定的水分特征曲線參數(shù)及非飽和導(dǎo)水系數(shù)與實(shí)際土柱內(nèi)土體參數(shù)還存在一定的偏差,因此在模擬原狀黃土水分入滲的過程中,要選擇適當(dāng)?shù)耐了卣髑�經(jīng)典模型,考慮基質(zhì)吸力與含水率之間存在滯回曲線,并且要考慮吸濕脫濕對土水特征曲線的影響。
[Abstract]:China is the country with the largest loess coverage area. The loess plateau area of 440000 km2, not only covers a wide area, but also has a large thickness, loose structure and extremely unfavorable geological conditions. Its fragile geological environment, improper human engineering activities (improper slope excavation and irrigation) and concentrated rainfall pattern make the region the most frequent area of landslide geological disasters in China. Rainfall and irrigation infiltration are one of the main factors that induce loess landslide. Therefore, it is of great theoretical and engineering significance to carry out infiltration process of rainfall and irrigation water in undisturbed loess. In this paper, the indoor large undisturbed soil column test was used to simulate the different rainfall and irrigation model conditions, and the moisture meter was embedded in the lateral wall of the undisturbed soil column with a height of 1 meter, and the moisture meter was connected with the data mining system. The changes of water content of loess in four depths with time were observed, and the water migration law of undisturbed loess was studied. On the basis of this, the process of water migration was simulated by HYDRUS--1D numerical simulation method. It is of great scientific significance to understand the mechanism of rainfall type and irrigation type loess landslide. It is found that in the process of Rain Water infiltration along the undisturbed loess, the soil column has a relatively low water content in the early stage of infiltration, and the matrix potential is related to the water content, and its gradient is large, so the infiltration ability of the soil column is relatively strong. The volume moisture content increases rapidly. With the increase of time, Rain Water gradually entered the loess soil column, and the moisture content of the loess in the lower part of the soil column gradually increased, and the matrix potential gradient between the soil column and the upper loess gradually decreased. The ability of soil to accept water gradually decreases. Therefore, the loss of stability of loess slope is closely related to the decrease or even loss of soil matrix suction. In the process of re-irrigation, the initial moisture content is high and the matrix suction is relatively small. Under the action of the upper head pressure, matrix suction and gravity, the migration rate of the wetting front increases rapidly at the beginning, when the water moves to the bottom of the soil column. The matrix potential gradient is lost and the saturation infiltration is maintained. There is still a certain error between the soil column infiltration test results and the HYDRUS-1D numerical simulation results, which may be due to the deviation between the parameters of water characteristic curve and unsaturated water conductivity measured by small soil samples and the actual soil parameters in the soil column. Therefore, in the process of simulating the water infiltration of undisturbed loess, the appropriate classical model of soil-water characteristic curve should be selected, and the hysteretic curve between matrix suction and moisture content should be considered, and the influence of moisture absorption and desiccation on soil-water characteristic curve should be considered.
【學(xué)位授予單位】：北京工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：S152.72

【相似文獻(xiàn)】

相關(guān)期刊論文 前5條

1 陳偉;駱亞生;郭靖;;基于三軸剪切試驗(yàn)的原狀黃土結(jié)構(gòu)性研究[J];中國農(nóng)村水利水電;2012年07期

2 王松鶴;駱亞生;楊永俊;楊靜敬;;原狀黃土蠕變特性試驗(yàn)研究[J];水土保持通報(bào);2009年04期

3 陳昌祿;邵生俊;馬林;;考慮黃土結(jié)構(gòu)性的修正鄧肯-張模型研究[J];西北農(nóng)林科技大學(xué)學(xué)報(bào)(自然科學(xué)版);2011年11期

4 張寧寧;駱亞生;沙磊;;含水率對非飽和原狀黃土強(qiáng)度的影響[J];水土保持通報(bào);2013年05期

5 ;[J];;年期

相關(guān)會議論文 前5條

1 扈勝霞;陳正漢;王克宇;;非飽和原狀黃土的固結(jié)試驗(yàn)研究[A];第九屆全國巖石力學(xué)與工程學(xué)術(shù)大會論文集[C];2006年

2 駱亞生;謝定義;田堪良;;非飽和原狀黃土在動荷條件下的孔隙壓力變化[A];中國土木工程學(xué)會第九屆土力學(xué)及巖土工程學(xué)術(shù)會議論文集（上冊）[C];2003年

3 李喜安;黃潤秋;周健;鄧亞虹;趙寧;洪勃;;原狀黃土三軸拉伸特性研究[A];2014年全國工程地質(zhì)學(xué)術(shù)大會論文集[C];2014年

4 邵生俊;;黃土的結(jié)構(gòu)性參數(shù)、強(qiáng)度特性及彈塑性本構(gòu)模型[A];第一屆全國巖土本構(gòu)理論研討會論文集[C];2008年

5 齊明山;;原狀黃土連續(xù)加荷k_0固結(jié)試驗(yàn)研究[A];盛世歲月——祝賀孫鈞院士八秩華誕論文選集[C];2006年

相關(guān)博士學(xué)位論文 前1條

1 鐘祖良;Q_2原狀黃土本構(gòu)模型及其在隧道工程中的應(yīng)用研究[D];重慶大學(xué);2008年

相關(guān)碩士學(xué)位論文 前10條

1 戴翔;考慮結(jié)構(gòu)性飽和原狀黃土的統(tǒng)一硬化本構(gòu)模型[D];西安建筑科技大學(xué);2015年

2 王衍匯;原狀黃土的聯(lián)合強(qiáng)度理論及其邊坡工程應(yīng)用[D];長安大學(xué);2016年

3 彭柳君;水在原狀黃土中的入滲過程研究[D];北京工業(yè)大學(xué);2016年

4 徐亞非;基于應(yīng)力變換的飽和原狀黃土的結(jié)構(gòu)性本構(gòu)模型[D];西安建筑科技大學(xué);2008年

5 王燕;原狀黃土的力學(xué)特性及其模擬[D];西安建筑科技大學(xué);2007年

6 高鵬;不同濕度原狀黃土靜、動力學(xué)特性及其與結(jié)構(gòu)性關(guān)系研究[D];西安理工大學(xué);2006年

7 扈勝霞;吸力對原狀黃土強(qiáng)度變形和水分變化的影響及其應(yīng)用[D];西北農(nóng)林科技大學(xué);2002年

8 何軍芳;原狀黃土的應(yīng)力路徑本構(gòu)關(guān)系研究[D];西安理工大學(xué);2008年

9 李佳;非飽和原狀黃土垂直邊坡土壓力及坡頂浸水滲透規(guī)律的試驗(yàn)研究[D];蘭州理工大學(xué);2009年

10 楊星;非飽和原狀黃土的固結(jié)特性及試驗(yàn)方法研究[D];長安大學(xué);2008年

，

本文編號：2326035