本文選題：碎石土 + CT技術��； 參考：《湘潭大學》2015年碩士論文

【摘要】：堆積碎石土作為一種常見的地質體在我國中南及西北地區(qū)廣泛分布,往往因降雨侵蝕或工程活動誘發(fā)地質災害(如滑坡和泥石流等)給我國帶來巨大的經(jīng)濟損失和人員傷亡。然而,因碎石土的物質組成復雜及其不規(guī)則的結構分布,給其工程性質與細觀結構的研究帶來了極大的困難。本文以湖南昭山地區(qū)某堆積碎石土斜坡為研究坡體,基于圖像處理技術和室內試驗研究坡表碎石土質量密度的空間變異特性,采用高倍光學顯微鏡觀察碎石土中細小黏粒的細觀孔隙特征,基于Darcy定理對碎石土進行室內飽和滲透試驗,并采用CT層析技術獲取碎石土試樣的孔隙特征,試圖探討碎石土的孔隙特征與其滲透系數(shù)的相關性,進而加深我們對這種復雜巖土材料的了解,為今后碎石土降雨滑坡類似工程問題提供參考。主要研究成果如下:1.研究坡體碎石土的含石量在49.75%~77.63%之間,沿坡面向下降低,其中0~10mm粒徑區(qū)間的顆粒含量沿坡面向下顯著增加,20~60mm粒徑區(qū)間的顆粒含量沿坡面向下呈減小趨勢,而10~20mm粒徑區(qū)間內變化不明顯;圓度頻率主要分布在0.7~0.9區(qū)間內,累計頻率的平均值為77.3%;塊體長短軸比的平均值位于1.4~1.497之間,且沿坡面向下有變小趨勢;碎石復雜度沿坡面向下有增加趨勢。2.試驗表明,相同質量細小黏粒土體的孔隙度與含水率之間呈二次曲線相關;孔隙數(shù)目、孔隙復雜度以及孔隙變異度隨著含水率的增加而減小,表明含水率越小孔隙的扭曲程度越高,孔隙就越復雜,且孔隙數(shù)含量越多,越有利于表層雨水下滲。3.正交試驗結果分析表明,對碎石土孔隙特征及其滲透系數(shù)影響的主次順序為:含石量干密度級配類型;碎石土的孔隙度、孔隙數(shù)目和滲透系數(shù)隨含石量增加而增加,而孔隙變異度和孔隙復雜度隨含石量的增加而減小;結合碎石土的孔隙特征分析,發(fā)現(xiàn)碎石土的滲透系數(shù)與其孔隙特征值之間存在指數(shù)遞減關系。
[Abstract]:As a common geological body, the accumulative gravel soil is widely distributed in the central, southern and northwest regions of China. It often brings huge economic losses and casualties to our country because of rainfall erosion or engineering activities induced geological disasters (such as landslides and debris flows). However, because of its complex composition and irregular structural distribution, it is very difficult to study its engineering properties and mesostructures. Based on image processing technique and laboratory test, the spatial variation characteristics of mass density of gravel soil on slope surface are studied in this paper, which is based on the slope of a pile of gravel in Zhaoshan area, Hunan Province. High power optical microscope was used to observe the microscopic pore characteristics of fine clay in gravel soil. The laboratory saturated permeability test was carried out on the basis of Darcy's theorem, and the pore characteristics of gravel soil sample were obtained by CT tomography. This paper attempts to discuss the correlation between pore characteristics and permeability coefficient of gravel soil, and then to deepen our understanding of this complex rock and soil material, and to provide reference for similar engineering problems of rainfall landslide of gravel soil in the future. The main research results are as follows: 1. The content of stone in the gravel soil of slope body is between 49.75% and 77.63%, and the content of particles in the 0~10mm particle size range increases significantly along the slope surface, and the particle content of the grain size range of 200.60 mm decreases along the slope surface. But the variation of 10~20mm particle size range is not obvious, the roundness frequency is mainly distributed in 0.7 ~ 0.9 region, the average value of cumulative frequency is 77.3%, the average value of the long and long axis ratio of block is between 1.4 and 1.497, and there is a tendency to decrease along the slope. The gravel complexity increased along the slope. 2. 2. The results show that the porosity of fine clay soil of the same mass is conic with water content, and the number of pores, the complexity of pores and the variation of porosity decrease with the increase of water content. The smaller the water content is, the higher the distortion degree of pore is, the more complex the pore is, and the more the content of pore number is, the more favorable to surface Rain Water's infiltration. 3. The results of orthogonal test show that the primary and secondary order of influence on pore characteristics and permeability coefficient of gravel soil is as follows: dry density gradation type of rock content, porosity, number of pores and permeability coefficient of gravel soil increase with the increase of stone content. The porosity variation and pore complexity decrease with the increase of stone content, and the relationship between permeability coefficient and pore characteristic value is found to be exponentially decreasing according to the analysis of pore characteristics of gravel soil.
【學位授予單位】：湘潭大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU43

【參考文獻】

相關期刊論文 前1條

1 周中;傅鶴林;劉寶琛;譚捍華;龍萬學;羅強;;土石混合體滲透性能的試驗研究[J];湖南大學學報(自然科學版);2006年06期

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本文編號：1824961