本文選題：非飽和黃土 + 飽和-非飽和滲流分析��； 參考：《蘭州交通大學》2017年碩士論文

【摘要】：常年處于干旱地區(qū)的黃土通常都是非飽和土,在降雨條件下,由于雨水的入滲往往會導致邊坡失穩(wěn)。究其原因,降雨條件下,黃土邊坡表層土體含水量增大,基質(zhì)吸力逐漸消散,進而引起非飽和黃土抗剪強度減小,從而引發(fā)滑坡。降雨是引發(fā)滑坡的主要因素,降雨條件下邊坡穩(wěn)定性分析早已成為巖土界的重要課題。研究降雨過程中邊坡水分場及穩(wěn)定性隨時間、空間的動態(tài)變化對邊坡穩(wěn)定性研究和滑坡預測有重要意義。文章以飽和—非飽和滲流理論為基礎,研究降雨條件下邊坡水分場的變化規(guī)律,分析了不同降雨強度、降雨持續(xù)時間、邊坡坡高、坡度以及黃土節(jié)理對邊坡表層土體含水量和孔隙水壓力的影響,然后基于瞬態(tài)滲流分析結(jié)果,結(jié)合極限平衡法對邊坡穩(wěn)定性的動態(tài)變化過程進行分析,最后對邊坡進行了錨桿抗滑樁加固設計,以及對加固后邊坡的穩(wěn)定性進行計算。具體的研究工作如下:(1)歸納總結(jié)了飽和—非飽和滲流基礎理論。以達西定律和能量守恒定律為基礎,歸納總結(jié)了飽和—非飽和滲流微分方程以及微分方程的定解條件,用以后續(xù)有限元數(shù)值計算的基礎。(2)考慮降雨條件,進行了非飽和黃土瞬態(tài)滲流計算,得到了不同降雨強度、降雨持續(xù)時間、邊坡坡高、坡度以及黃土節(jié)理存在下邊坡土體水分場的變化規(guī)律,即不同降雨條件對非飽和黃土本體積含水量、孔隙水壓力的影響。由計算結(jié)果得到:降雨條件下,由于雨水入滲主要影響邊坡的表層土體,主要表現(xiàn)為土體含水量增加,出現(xiàn)暫態(tài)飽和區(qū),基質(zhì)吸力(負孔隙水壓力)減小;此外,盡管整個邊坡表層土體整體變化規(guī)律是含水量增加,基質(zhì)吸力減小,但土體含水量和基質(zhì)吸力的變化速率和變化幅度因土體位置而異,越靠近坡腳處的表層土體含水量和孔隙水壓力變化的速率和幅度越大,坡頂處表層土體含水量和孔隙水壓力變化速度和幅度較小。坡腳處最開始土體出現(xiàn)暫態(tài)飽和區(qū),隨著降雨時間增大,該區(qū)沿坡面向上延伸,最終整個邊坡表層土體都出現(xiàn)飽和區(qū)。降雨過程中,當考慮黃土節(jié)理存在時,雨水的入滲速率和深度明顯增大,邊坡表層土體出現(xiàn)飽和區(qū)域時間提早。(3)基于飽和—非飽和滲流計算結(jié)果分析了降雨過程中黃土深路塹邊坡的穩(wěn)定安全系數(shù)的動態(tài)變化。將滲流計算得到的結(jié)果和非飽和土抗剪強度理論相結(jié)合,運用極限平衡法計算不同降雨強度和降雨持續(xù)時間下邊坡的穩(wěn)定安全系數(shù)。由計算結(jié)果可以看到:降雨條件不同邊坡穩(wěn)定安全系數(shù)值不同,同一降雨強度下,穩(wěn)定安全系數(shù)隨著時間的增加而減小;相同降雨持時,雨強大,系數(shù)越小;邊坡高度增大時,邊坡表層土體含水量的最大值大致相同,但是雨水的入滲深度則隨著坡度的增大而增大,因此受降雨影響的土體去增大了,抗剪強度減小的土體區(qū)域增大,導致邊坡穩(wěn)定安全系數(shù)有所減小;邊坡坡度增大時,邊坡穩(wěn)定安全系數(shù)小;當考慮節(jié)理存在時,降雨過程中,存在節(jié)理區(qū)的邊坡穩(wěn)定安全系數(shù)減小的幅度逐漸降低,這是由于降雨初期雨水入滲速度快,邊坡表層土體含水量增大的速率快,降雨后期土體含水量增大速率較緩,降雨3d后邊坡表層土體達到飽和,而均質(zhì)邊坡土體含水量增大幅度差異相較之下沒那么明顯,因而邊坡穩(wěn)定安全系數(shù)增大速率也沒明顯變化,降雨3d后邊坡土體未達到飽和狀態(tài)。(4)對邊坡采用錨桿抗滑樁加固方案的比選以及對支護后邊坡穩(wěn)定安全系數(shù)進行了計算。由計算結(jié)果可知:當錨桿按與水平面成15°夾角布置時得到的邊坡穩(wěn)定安全系數(shù)最大;錨桿加固坡面能夠較好的提高邊坡的穩(wěn)定,雖然加固后的邊坡穩(wěn)定安全系數(shù)同樣會隨著降雨而有所減小,但降雨3d后邊坡的穩(wěn)定安全系數(shù)依然較大,因而可以保證邊坡有較高的穩(wěn)定性。
[Abstract]:In the arid area, the loess is usually unsaturated soil. Under rainfall conditions, the infiltration of rainwater often leads to the instability of the slope. The reason is that under the conditions of rainfall, the soil water content in the surface of the loess slope increases and the matrix suction gradually dissipates, which causes the decrease of the shear strength of unsaturated loess, thus triggering the landslide. The main factor of landslides, the analysis of slope stability under rainfall has already become an important subject of rock and soil. It is of great significance to study the dynamic changes of slope water field and stability with time and space in the process of rainfall. The paper is based on the theory of saturated unsaturated seepage, and studies the conditions of rainfall. The influence of different rainfall intensity, rainfall duration, slope height, slope and loess joint on the soil water content and pore water pressure on the surface of the slope is analyzed. Then based on the transient seepage analysis results, the dynamic change process of slope stability is analyzed with the limit equilibrium method. The slope is designed by anchor anti slide pile and the stability of the reinforced slope is calculated. The specific research work is as follows: (1) the basic theory of saturated unsaturated seepage is summarized. Based on Darcy's law and the law of conservation of energy, the differential equation of saturated unsaturated seepage and the definite solution of differential equation are summed up. The basis of the subsequent finite element numerical calculation. (2) considering the conditions of rainfall, the transient seepage calculation of unsaturated loess is carried out. The variation rules of different rainfall intensity, rainfall duration, slope height, slope and loess joints under the existence of soil water are obtained, that is, the volume water content of unsaturated loess with different rainfall conditions The effect of pore water pressure. It is obtained from the calculation results: under the condition of rainfall, the main performance of the surface soil of the slope is the increase of the soil water content, the transient saturation area and the matrix suction (negative pore water pressure) decrease because of the rainfall infiltration. In addition, although the whole change law of the whole soil surface is the increase of water content, the substrate is absorbed. The change rate and amplitude of soil water content and matrix suction vary with the soil position. The greater the rate and amplitude of soil water content and pore water pressure change near the foot of the slope, the change speed and amplitude of soil water content and pore water pressure at the top of the slope is small. In the saturated area, with the increase of rainfall time, the area extends along the slope, and eventually the whole slope of the slope is saturated. In the process of rainfall, when the Loess joints are considered, the infiltration rate and depth of the rainwater increase obviously, and the saturated area of the slope surface soil appears early. (3) the calculation results based on saturated unsaturated seepage are divided. The dynamic change of the stability safety factor of the Loess deep cutting slope is analyzed. The result of seepage calculation and the theory of unsaturated soil shear strength are combined to calculate the stability safety factor of the slope under the different rainfall intensity and rainfall duration by the limit equilibrium method. The stability safety factor of slope stability is different, and the stability safety coefficient decreases with the increase of time. When the same rainfall is held, the rain is strong and the coefficient is smaller. When the slope height increases, the maximum water content of the soil surface is approximately the same, but the infiltration depth of the rain is increased with the increase of the slope, so the rain shadow is reduced. The soil area is increased, the soil area of the shear strength decreases and the slope stability safety factor decreases. When the slope increases, the slope stability safety factor is small. When the joints exist, the slope stability safety coefficient decreases gradually during the rainfall process, which is due to the initial rainfall. The rate of soil moisture content in the surface of the slope is faster, the soil moisture content increases slowly in the later period of rainfall, and the soil water content of the slope is saturated after 3D rainfall, and the soil moisture content of the slope is not so obvious as that in the same slope, so the increase rate of the slope stability safety coefficient does not change obviously. After the rainfall, the rainfall is 3D. The slope soil soil is not saturated. (4) the comparison and selection of the anchor anti slide pile for the slope and the stability safety factor of the slope after the support are calculated. The results show that the stability safety factor of the slope is maximum when the bolt is arranged in the angle of 15 degrees with the horizontal plane, and the slope surface can improve the slope better. The stability of the slope is also stable, although the stability safety factor of the slope will decrease with the rainfall, but the stability safety factor of the slope is still large after the rainfall of 3D, so it can guarantee the high stability of the slope.
【學位授予單位】：蘭州交通大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：U416.14

【參考文獻】

相關期刊論文 前10條

1 鄭敏洲;;某滑坡非飽和土土水特征曲線試驗研究[J];路基工程;2014年01期

2 周勇;朱彥鵬;;對“預應力錨桿柔性支護體系的錨桿抗拔力研究”討論的答復[J];巖土力學;2013年12期

3 劉新榮;張梁;余瑜;劉坤;;降雨條件下酉陽大涵邊坡滑動機制研究[J];巖土力學;2013年10期

4 周勇;朱彥鵬;;預應力錨桿柔性支護體系的錨桿抗拔力研究[J];巖土力學;2012年02期

5 李榮建;鄭文;王莉平;邵生俊;;非飽和土邊坡穩(wěn)定性分析方法研究進展[J];西北地震學報;2011年S1期

6 于玉貞;林鴻州;李榮建;李廣信;;非穩(wěn)定滲流條件下非飽和土邊坡穩(wěn)定分析[J];巖土力學;2008年11期

7 林鴻州;李廣信;于玉貞;呂禾;;基質(zhì)吸力對非飽和土抗剪強度的影響[J];巖土力學;2007年09期

8 劉三倉;隋國秀;劉志偉;;非飽和 飽和狀態(tài)下黃土地基中灌注樁承載性能的研究[J];巖土工程學報;2007年01期

9 葉為民,錢麗鑫,白云,陳寶;由土 水特征曲線預測上海非飽和軟土滲透系數(shù)[J];巖土工程學報;2005年11期

10 繆林昌,殷宗澤;非飽和土的剪切強度[J];巖土力學;1999年03期

相關會議論文 前1條

1 李萍;張毅;李輝山;;土質(zhì)高邊坡在降雨條件下的滲流與穩(wěn)定分析[A];第十屆全國巖石力學與工程學術大會論文集[C];2008年

相關博士學位論文 前8條

1 劉朋飛;非飽和黃土滑坡失穩(wěn)機理研究[D];長安大學;2013年

2 羅強;巖質(zhì)邊坡穩(wěn)定性分析理論與錨固設計優(yōu)化研究[D];中南大學;2010年

3 劉偉平;錨桿（索）的非局部摩擦效應及其抗拔力研究[D];南昌大學;2010年

4 張雪東;土水特征曲線及其在非飽和土力學中應用的基本問題研究[D];北京交通大學;2010年

5 陳科平;高速公路邊坡穩(wěn)定性模糊評價及加固治理研究[D];中南大學;2007年

6 林鴻州;降雨誘發(fā)土質(zhì)邊坡失穩(wěn)的試驗與數(shù)值分析研究[D];清華大學;2007年

7 李順群;非飽和土的吸力與強度理論研究及其試驗驗證[D];大連理工大學;2006年

8 戚國慶;降雨誘發(fā)滑坡機理及其評價方法研究[D];成都理工大學;2004年

相關碩士學位論文 前10條

1 寧英成;非飽和土土水特性曲線與滲透系數(shù)試驗研究[D];大連理工大學;2014年

2 羅波;降雨條件下非飽和黃土邊坡穩(wěn)定性分析[D];蘭州交通大學;2014年

3 施炳軍;降雨入滲下邊坡滲流場與穩(wěn)定性數(shù)值分析[D];昆明理工大學;2013年

4 高剛;降雨入滲條件下邊坡穩(wěn)定性數(shù)值分析[D];蘭州大學;2013年

5 彭剛;大斷面黃土隧道施工過程數(shù)值模擬研究[D];長安大學;2012年

6 曲國鵬;降雨入滲作用下非飽和黃土滑坡穩(wěn)定性研究[D];長安大學;2012年

7 楊學文;考慮降雨和滲流條件下的土質(zhì)邊坡穩(wěn)定性分析[D];華中科技大學;2011年

8 紀海波;黃土地區(qū)公路邊坡穩(wěn)定性分析[D];武漢科技大學;2011年

9 李紀偉;降雨入滲作用下非飽和土滲流場與應力場耦合分析[D];華中科技大學;2011年

10 黃福明;降雨入滲誘發(fā)滑坡穩(wěn)定性分析[D];浙江大學;2010年

，

本文編號：1977389