降雨對廣西含泥質夾層碎屑巖邊坡的穩(wěn)定性影響研究
發(fā)布時間:2018-03-09 22:46
本文選題:碎屑巖 切入點:泥質夾層 出處:《廣西大學》2015年碩士論文 論文類型:學位論文
【摘要】:本文以2014年廣西壯族自治區(qū)國土資源廳“廣西碎屑巖地區(qū)地質災害防治研究”項目為依托,在收集整理第一手資料的基礎上采用統(tǒng)計分析、數(shù)值模擬及理論分析相結合的方法,研究廣西碎屑巖地區(qū)滑坡災害的分布規(guī)律、發(fā)育特征及碎屑巖區(qū)滑坡與降雨的關系,分析降雨對碎屑巖類邊坡穩(wěn)定性的影響。主要研究內容包括:1、統(tǒng)計分析2005年~2013年廣西碎屑巖分布區(qū)地質災害資料。分析結果表明滑坡是廣西碎屑巖地區(qū)分布最廣泛的地質災害,以小型、淺層滑坡為主,降雨是最主要的誘發(fā)因素之一。2、研究廣西碎屑巖分布區(qū)滑坡災害與降雨的關系。研究結果表明,滑坡的發(fā)生與降雨前1-4天的降雨過程有較好的相關性,其中與滑坡前兩天的降雨相關性最好;降雨型滑坡主要發(fā)生在暴雨期間;滑坡的發(fā)生時間滯后于降雨峰值出現(xiàn)的時間,并隨著降雨強度的增加滯后時間有縮短的趨勢。3、統(tǒng)計分析大量歷史滑坡的勘察資料,分析廣西碎屑巖區(qū)滑坡的地層巖性和各層土體的物理力學特性。分析結果表明,碎屑巖地區(qū)的滑坡主要發(fā)生在含有泥質夾層的邊坡中,在降雨條件下邊坡多沿泥質夾層發(fā)生破壞;泥質夾層強度較低,遇水易發(fā)生崩解軟化,強度大幅步降低,為滑坡的形成提供了潛在滑移面。4、根據(jù)廣西碎屑巖地區(qū)邊坡特點建立碎屑巖與泥質帶互層的邊坡模型,利用Geo-studio數(shù)值分析軟件中的SEEP/W和SLOPE/W模塊模擬分析含有泥質夾層的邊坡中泥質夾層對邊坡內滲流場和邊坡穩(wěn)定性的影響。模擬結果表明,當降雨強度、降雨時間達到一定程度時,泥質夾層表面將出現(xiàn)暫時的積水區(qū),降雨強度越大、降雨時間越長,積水越明顯;泥質夾層被積水浸泡飽和度大幅增加、孔隙水壓力升高、基質吸力降低、土體抗剪強度降低形成一層軟弱帶,邊坡的穩(wěn)定性降低;在相同的降雨時間里,坡度越小,降雨對坡體內部的土體的孔隙水壓力影響越大,對邊坡的穩(wěn)定性影響越大;降雨誘發(fā)的滑坡潛在滑動面主要分布在相對隔水層表面或軟硬土層的接觸面。
[Abstract]:In 2014, based on the project of "study on the prevention and control of geological hazards in the clastic rock region of Guangxi" of the Department of Land and Resources of Guangxi Zhuang Autonomous region, this paper adopts the methods of combining statistical analysis, numerical simulation and theoretical analysis on the basis of collecting and arranging first-hand data. The distribution law, development characteristics and relationship between landslide and rainfall in clastic rock area of Guangxi are studied. This paper analyzes the influence of rainfall on the stability of clastic rock slope. The main research contents include: 1, statistical analysis of geological hazard data of clastic rock distribution area in Guangxi from 2005 to 2013. The results show that landslide is the most widely distributed geological hazard in the clastic rock area of Guangxi. The relationship between landslide disaster and rainfall in the distribution area of clastic rocks in Guangxi is studied. The results show that the occurrence of landslide has a good correlation with the rainfall process 1-4 days before rainfall. The correlation between landslide and rainfall two days before the landslide is the best; the rainfall type landslide mainly occurs during the rainstorm; the time of landslide occurrence lags behind the time of peak rainfall. With the increase of rainfall intensity, the lag time has a tendency of shortening. 3. The investigation data of a large number of historical landslides are statistically analyzed, and the stratigraphic lithology and physical and mechanical properties of each layer of soil in the clastic rock area of Guangxi are analyzed. The landslide in the clastic rock area mainly occurs in the slope with muddy intercalation. Under the condition of rainfall, the slope is destroyed along the muddy intercalation, the strength of the muddy intercalation is low, it is easy to collapse and soften when the water is encountered, and the strength of the muddy intercalation decreases greatly. The potential slip surface. 4 is provided for the formation of the landslide. According to the characteristics of the clastic rock slope in Guangxi, the slope model of interbedded clastic rock and muddy zone is established. The influence of muddy interlayer on the seepage field and slope stability in a slope with muddy intercalation is simulated by using SEEP/W and SLOPE/W modules in Geo-studio software. The simulation results show that when rainfall intensity and rainfall time reach a certain degree, The surface of the muddy intercalation will have temporary hydrological zone, the greater the rainfall intensity, the longer the rainfall time, the more obvious the water is, the higher the saturation of soaking by water, the higher the pore water pressure, the lower the matrix suction. In the same rainfall time, the smaller the slope degree, the greater the influence of rainfall on the pore water pressure of the soil, and the greater the influence on the slope stability. The potential sliding surface of the landslide induced by rainfall is mainly distributed on the surface of relative water barrier or the interface of soft and hard soil.
【學位授予單位】:廣西大學
【學位級別】:碩士
【學位授予年份】:2015
【分類號】:TU457
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