【作者】 刘海娇； 鲁晓兵； 王淑云； 张旭辉；

【Author】 LIU Haijiao;LU Xiaobing;WANG Shuyun;ZHANG Xuhui;Department of Engineering Sciences,University of Chinese Academy of Sciences;Institutes of Mechanics,Chinese Academy of Sciences;

【机构】 中国科学院大学工程科学学院； 中国科学院力学研究所；

【摘要】 在渗流条件下,松散土体中的细颗粒会逐渐被水流带走,从而改变土体的颗粒级配及微结构,进而影响土体的宏观力学参数如强度和弹性模量等。本文针对土体中细颗粒迁移对土体宏微观参数的影响,开展基于核磁共振仪器的微观孔喉结构观测实验及基于孔隙网络模型的计算。研究表明,沿土体深度方向细颗粒随孔隙渗流而下移,中部聚集程度最高,这样导致中部小孔隙明显大于上部和下部。在渗流过程中,孔隙水并不能充满整个区域,上、中、下部均存在没有被水波及的范围,中部未波及范围最大,渗流通道最少,相同流量下的孔隙水压更高,因此中部的强度和刚度变化也最大。更多还原

【Abstract】 Fine grains in loose soils can be erosion and re-deposition by seepage which can change the grain series and micro-structure of the soils.Accordingly the macro properties such as strength and modulus can be changes.In this paper test based on nuclear magnetic resonance instrument observation and simulation based on pore network model were carried out to analyze the effects of the migration of fine grains on the soils macro-properties.It is shown that fine grains are eroded and migrated along depth with pore water flow and most of them are assembled at the middle of the soil layer,which causes the porosity at the diddle layer is obvious smaller than that of the upper and lower layers.During seepage,pore water cannot flows through the whole area.In fact,at the upper,lower and middle layers,there all exist small or large areas which are not filled by water.Simulation shows that the area of the middle layer spread by water and the flow channels are the least,therefore under the same flow rate the pore water pressure is higher,so the changes of the strength and stiffness in the middle layer are the largest.更多还原