本文選題：膨脹土　切入點：干濕循環(huán)　出處：《西北農(nóng)林科技大學》2015年碩士論文　論文類型：學位論文

【摘要】：論文以膨脹土為研究對象,以膨脹土的干濕循環(huán)效應為研究目的,通過室內(nèi)膨脹土單軸抗拉試驗、直接剪切試驗、無荷膨脹率試驗,較為全面地揭示了膨脹土經(jīng)過干濕循環(huán)后土體強度和變形的變化規(guī)律,并分析了其產(chǎn)生干濕循環(huán)效應的機制和造成試驗結果的原理,主要研究結論如下:1.通過膨脹土的無荷膨脹率試驗,研究了膨脹土在干濕循環(huán)條件下其脹縮變形的變化規(guī)律,并建立膨脹土脹縮率與初始含水率、干密度和脫濕溫度的關系。得出在單變量條件下,膨脹土的脹縮指標隨初始含水率的增加而減小,隨干密度的增加而增大,隨脫濕溫度的增大而增大。隨干濕循環(huán)次數(shù)的增多,試樣的相對膨脹率逐漸減小,絕對膨脹率則而增大,最終趨于一穩(wěn)定值。并得出膨脹土的干縮濕脹變形(相對膨脹率)并不完全可逆。2.對膨脹土在反復干濕循環(huán)作用下的滲透特性進行了室內(nèi)試驗研究。對不同干濕循環(huán)次數(shù)的試樣進行變水頭滲透試驗。膨脹土的下滲強度均隨著干濕循環(huán)次數(shù)的增加而增加。滲透系數(shù)隨干濕循環(huán)次數(shù)的增加而增加,隨干濕循環(huán)幅度的增大而增加,隨脫濕溫度的減小而增加。3.通過室內(nèi)單軸抗拉,研究膨脹土在干濕循環(huán)條件下強度的變化規(guī)律,在此基礎上探討了干濕循環(huán)條件下膨脹土強度與初始含水率、干密度、干濕循環(huán)次數(shù)、循環(huán)幅度、脫濕溫度的關系。4.通過室內(nèi)直剪試驗,研究干濕循環(huán)條件下膨脹土強度與初始含水率、干密度、干濕循環(huán)次數(shù)、循環(huán)幅度、脫濕溫度的關系。并建立抗剪強度與不同試驗參數(shù)的強度衰減公式。由試驗結果可知,膨脹土的干濕循環(huán)強度衰減主要發(fā)生在1~3次循環(huán),且強度穩(wěn)定的次數(shù)隨循環(huán)幅度的增大而減小,在相同初始含水率、干密度下建立了膨脹土強度參數(shù)與干濕循環(huán)次數(shù)、干濕循環(huán)幅度、脫濕溫度的表達式。
[Abstract]:This paper takes expansive soil as the research object, takes the dry-wet cycle effect of expansive soil as the research purpose, through indoor expansive soil uniaxial tensile test, direct shear test, no load expansion test. The variation law of strength and deformation of expansive soil after dry-wet circulation is revealed, and the mechanism of producing dry-wet cycle effect and the principle of test result are analyzed. The main conclusions are as follows: 1. Through the load free expansion test of expansive soil, the variation law of swelling and shrinkage deformation of expansive soil under dry and wet cycling conditions is studied, and the expansion and shrinkage ratio and initial moisture content of expansive soil are established. The relation between dry density and desiccant temperature. It is concluded that under the condition of single variable, the swelling and shrinkage index of expansive soil decreases with the increase of initial moisture content, increases with the increase of dry density, increases with the increase of desiccant temperature, and increases with the increase of dry-wet cycle times. The relative expansion rate of the sample decreases gradually, while the absolute expansion rate increases. Finally, a stable value is obtained, and it is concluded that the swelling deformation (relative expansion ratio) of expansive soil is not completely reversible. 2. The permeability characteristics of expansive soil under repeated dry-wet cycle are studied in laboratory. The infiltration strength of expansive soil increased with the increase of dry-wet cycle times, and the permeability coefficient increased with the increase of dry-wet cycle times. With the increase of dry-wet cycle amplitude and the decrease of desiccant temperature, the strength of expansive soil under dry-wet cycle is studied. On this basis, the relationship between the strength of expansive soil and initial moisture content, dry density, dry and wet cycle times, cycle amplitude and desiccant temperature under dry and wet cycling conditions is discussed. The relationship between strength and initial moisture content, dry density, dry-wet cycle number, cycle amplitude and desiccant temperature of expansive soil under dry and wet cycling conditions was studied. The formula of shear strength and strength attenuation of different test parameters was established. The attenuation of dry-wet cycle strength of expansive soil mainly occurs in 1 ~ 3 cycles, and the number of stable strength decreases with the increase of cyclic amplitude. Under the same initial moisture content and dry density, the strength parameters and dry-wet cycle times of expansive soil are established. The range of dry and wet circulation and the expression of dehumidification temperature.
【學位授予單位】：西北農(nóng)林科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU443

【參考文獻】

相關期刊論文 前3條

1 李培勇;楊慶;欒茂田;汪東林;;非飽和膨脹土裂隙開展深度影響因素研究[J];巖石力學與工程學報;2008年S1期

2 李珍玉;肖宏彬;金文婷;易文;;南寧膨脹土非線性流變模型研究[J];巖土力學;2012年08期

3 譚曉慧;辛志宇;沈夢芬;汪賢恩;徐全;;濕脹條件下合肥膨脹土土-水特征研究[J];巖土力學;2014年12期

相關碩士學位論文 前1條

1 劉平;降雨條件下考慮裂隙的膨脹土邊坡非穩(wěn)定滲流數(shù)值模擬[D];長沙理工大學;2007年

，

本文編號：1563029