本文選題：紅土壩坡模型試驗(yàn) + 干濕循環(huán)作用　； 參考：《昆明理工大學(xué)》2017年碩士論文

【摘要】：本文以云南紅土為研究對象,結(jié)合云南極端干旱和雨季頻繁交替的干濕作用及這種干濕作用對云南紅土型壩坡的影響,提出開展“干濕循環(huán)下紅土模型壩坡劣化特性研究”這一課題。以室內(nèi)紅土壩坡模型試驗(yàn)為基礎(chǔ),以庫水位升降作為干濕循環(huán)控制條件,結(jié)合宏微觀試驗(yàn)方法,研究干濕循環(huán)過程中紅土模型壩坡的坡面劣化特性、土水壓力變化特性、抗剪強(qiáng)度特性、壓縮特性及其對應(yīng)的微結(jié)構(gòu)特性,分析了紅土模型壩坡劣化特性規(guī)律。該研究年成果對于實(shí)際紅土型病險(xiǎn)大壩的病害防治具有重要意義。干濕循環(huán)下紅土模型壩坡試驗(yàn)表明:增濕過程中土壓力減小,孔隙水壓力增大,脫濕過程中,土壓力增大,孔隙水壓力減小。隨干濕循環(huán)次數(shù)增大,壩坡高程較低時(shí)紅土體的土壓力呈減小穩(wěn)定趨勢,高程較大時(shí)土壓力呈增大穩(wěn)定趨勢。隨干濕循環(huán)次數(shù)增大,壩坡紅土體的孔隙水壓力呈增大趨勢。庫水位升降的干濕循環(huán)過程中,水分反復(fù)遷入遷出引起的吸水膨脹、失水收縮的加深加劇,紅土壩坡呈現(xiàn)出坡頂開裂、大塊體剝落、坡腳顆粒堆積的上凹下凸的坡面輪廓線變化特征,改變了壩坡紅土體的坡面輪廓線形狀,出現(xiàn)壩坡劣化特性。干濕循環(huán)下壩坡紅土宏觀特性試驗(yàn)表明:干濕循環(huán)前后,壩坡紅土粘粒百分含量降低,含水率先增大后減小,干密度減小,抗剪強(qiáng)度降低,壓縮性能增大。隨壩坡高程增大,粘粒百分含量降低,含水率降低,干密度減小,抗剪強(qiáng)度降低,壓縮性能增大。隨干密度增大,抗剪強(qiáng)度、壓縮性能增大。干濕循環(huán)下壩坡紅土微結(jié)構(gòu)特性試驗(yàn)表明:干濕循環(huán)次數(shù)的影響下,隨干濕循環(huán)次數(shù)增加,模型壩坡逐漸劣化,大團(tuán)粒結(jié)構(gòu)減少,細(xì)顆粒增多,土體變得松散,孔隙率、分維數(shù)、顆粒個(gè)數(shù)增大,壩坡高程的影響下,壩坡高程越大,土體就越松散,劣化較為嚴(yán)重,孔隙率、分維數(shù)、顆粒個(gè)數(shù)越大,干密度的影響下,干密度越大,土體越密實(shí),劣化程度較輕,孔隙率、分維數(shù)、顆粒個(gè)數(shù)越小。干濕循環(huán)下模型壩坡逐漸劣化,壩坡土體的宏微觀特性存在一定對應(yīng)關(guān)系。干濕循環(huán)過程中,水分對壩坡土體有軟化、化學(xué)溶解等作用,水化膜增大變薄,壩坡裂縫逐漸變大以及膠結(jié)作用減弱,使壩坡強(qiáng)度等特性降低,對壩坡抵抗庫水位干濕循環(huán)、惡劣降雨干濕環(huán)境、風(fēng)暴以及凍融環(huán)境不利,提供一定的工程參考意義。
[Abstract]:In this paper, Yunnan laterite is taken as the research object, combined with the dry and wet action of extreme drought and frequent alternate rainy season and the influence of this kind of dry and wet action on the red soil dam slope in Yunnan. The subject of "study on deterioration characteristics of Red soil Model Dam Slope under dry and Wet cycle" is put forward. On the basis of indoor red earth dam slope model test, taking the rise and fall of reservoir water level as the control condition of dry and wet circulation, combined with macro and micro test method, the slope deterioration characteristics and soil water pressure variation characteristics of red earth model dam slope during dry-wet cycle are studied. The characteristics of shear strength, compression and its corresponding microstructure are analyzed, and the degradation characteristics of laterite model dam slope are analyzed. The results of this study are of great significance to the prevention and treatment of actual red earth dam. The results of dam slope test of laterite model under dry and wet cycles show that the soil pressure decreases, pore water pressure increases during humidification, and pore water pressure decreases during dehumidification. With the increase of dry-wet cycle times, the earth pressure of laterite decreases when the height of dam slope is low, and increases with the increase of height. With the increase of dry and wet cycles, the pore water pressure of red soil on dam slope increases. During the dry-wet cycle of water level rise and fall, the water absorption and expansion caused by water moving in and out repeatedly, the deepening of the shrinkage of water loss, the cracking of the slope of the red earth dam, the spalling of the large block, The shape of slope profile of red earth body on the slope of the slope is changed and the deterioration of the slope occurs because of the variation characteristics of the contour line of the slope in the upper concave and the lower convex of the grain accumulation at the foot of the slope. The macroscopical characteristic test of red soil on dam slope under dry and wet circulation shows that before and after dry and wet cycling, the clay content of red soil in dam slope decreases, the moisture content increases first and then decreases, the dry density decreases, the shear strength decreases and the compressibility energy increases. With the increase of the height of the dam slope, the percentage content of clay particles decreases, the moisture content decreases, the dry density decreases, the shear strength decreases and the compressibility energy increases. With the increase of dry density, shear strength and compressibility increase. The experimental results of microstructural characteristics of red soil on dam slope under dry and wet cycles show that with the increase of dry-wet cycle times, the dam slope of the model gradually deteriorates, the large aggregate structure decreases, the fine particles increase, and the soil becomes loose and porosity. Under the influence of the increase of fractal dimension, the number of particles and the height of dam slope, the larger the height of dam slope, the looser the soil, the worse the deterioration, the larger the porosity, fractal dimension, the number of particles, and the more dry density, the larger the dry density, the more dense the soil. The degree of deterioration is lighter, the porosity, fractal dimension and the number of particles are smaller. Under the dry and wet cycle, the model dam slope is gradually deteriorating, and the macro and micro characteristics of the dam slope soil have a certain corresponding relationship. In the process of dry-wet circulation, water has the functions of softening and chemical dissolution of dam slope soil, increasing and thinning of hydration film, increasing cracks of dam slope and weakening of cementation, which makes the strength of dam slope lower, and resists the dry and wet circulation of reservoir water level to dam slope. Severe rainfall dry and wet environment, storm and freezing and thawing environment are unfavorable, which provides certain engineering reference significance.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TV223

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 楊迎;陳勇;李平;唐杰鑫;;密實(shí)度及有荷干濕循環(huán)對土-水特征曲線的影響[J];水電能源科學(xué);2016年03期

2 陳開圣;;干濕循環(huán)作用下紅黏土抗剪強(qiáng)度特性研究[J];公路;2016年02期

3 趙雄飛;陳開圣;;干濕循環(huán)條件下紅粘土的脹縮變形特性研究[J];貴州大學(xué)學(xué)報(bào)(自然科學(xué)版);2016年01期

4 趙立業(yè);薛強(qiáng);萬勇;劉磊;;干濕循環(huán)作用下高低液限黏土防滲性能對比研究[J];巖土力學(xué);2016年02期

5 吳s，

本文編號：1817899