堆积碎石土细观孔隙空间特征对其渗透特性的定量影响

发布时间：2018-03-16 21:03

本文选题：碎石土　切入点：滑坡　出处：《中南大学学报(自然科学版)》2017年05期 　论文类型：期刊论文

【摘要】：堆积碎石土作为滑体物质往往因其细观结构差异对雨水入渗产生影响。基于CT扫描宏细观孔隙特征,以自制渗透仪研究级配(坡顶区域、坡腰区域、坡脚区域)、干密度(1.65,1.75和1.85 g/cm3)、含石率(30%~70%)等条件下碎石土的渗透规律。采用"最小累积差值"阈值选取方法对CT图像进行阈值分割,提取图像碎石和空隙形态,利用灰关联分析法定量分析各因素(碎石面积比率、空隙面积比率等)对渗透系数的影响。研究结果表明:空隙面积比率是影响渗透系数的主要因素;考虑含石率作为主要影响条件时,随着含石率的减少(从70%减至30%),空隙面积变异系数、空隙周长变异系数及空隙分形维数均呈现先增加后减少的趋势,存在1个含石率阈值使其碎石土的渗透系数最小;根据空隙面积比率(x)与碎石面积比率(y),获得渗透系数(k)拟合函数,其为运用图像处理技术估算滑坡坡表碎石土渗透系数提供简明有效的新途径。
[Abstract]:The accumulation of gravel as sliding material often affects Rain Water's infiltration due to its difference in microstructure. Based on the characteristics of macro and meso-pore of CT scanning, the gradation (slope top area, slope waist area) is studied by self-made osmometer. Under the conditions of slope foot area, dry density of 1.65g / cm ~ (3) and dry density of 1.85 g / cm ~ (3), rock content ratio of 30 ~ 70), the method of selecting threshold value of "minimum cumulative difference" is used to segment CT image and extract the shape of lithotripsy and void. The influence of various factors (gravel area ratio, void area ratio, etc.) on the permeability coefficient is quantitatively analyzed by using grey correlation analysis. The results show that the porosity area ratio is the main factor affecting the permeability coefficient. With the decrease of stone content (from 70% to 30g), the coefficient of variation of void area, the coefficient of variation of void circumference and the fractal dimension of voids show a trend of first increasing and then decreasing. According to the ratio of void area (x) to the ratio of gravel area (y), a fitting function of permeability coefficient (k) is obtained. It provides a simple and effective new way to estimate the permeability coefficient of macadam soil on landslide slope surface by using image processing technology.
【作者单位】：湘潭大学土木工程与力学学院;成都理工大学地质灾害防治与地质环境保护国家重点实验室;
【基金】：国家自然科学基金资助项目(51108397,51308485) 湖南省自然科学基金资助项目(2015JJ2136) 湖南省教育厅优秀青年基金资助项目(16B255)~~
【分类号】：P642.22

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