南疆绿洲区含残膜砂土击实特性试验研究

Experimental Study on Compaction Characteristics of Sandy Soil with Residual Film in Oasis Area of Southern Xinjiang

压实度是路基设计与施工的重要参数,由于南疆绿洲区大量农膜残留土壤,改变了路基土体的击实特性进而影响其压实度;结合该地区砂中含黏的土质特征,以含残膜砂土为试验材料,设计正交试验方案,研究了不同含水率(8%、10%、12%、14%、16%)、不同残膜含量(0、0.05%、0.1%、0.2%、0.3%、0.4%)和不同黏土含量(10%、20%、30%、40%)对砂土击实干密度的影响。研究结果表明:残膜的掺入对砂土最优含水率几乎没有影响;残膜含量对砂土干密度的影响受到黏土含量的影响,当黏土含量很低时,残膜含量对含残膜砂土干密度几乎无影响,黏土含量在10%~20%之间时,干密度随着残膜含量的增加先增加后减少,当黏土含量达到30%~40%时,干密度随残膜含量的增加呈波状变化;含残膜砂土的干密度随着黏土含量的增加呈对数增长趋势,但这种趋势受到残膜含量的影响,且黏土含量越高,影响越显著,当黏土含量<20%时,不同残膜含量砂土的干密度~黏土含量曲线几乎重合且大于素土,当黏土含量≥20%时,不同残膜含量的砂土干密度~黏土含量曲线离散,黏土含量越大,离散越大。

Compactness is an important parameter for subgrade design and construction,however,a large number of agricultural film stay in the soil of oasis area of southern Xinjiang areas,which changes the compaction characteristics of subgrade soil and then affects its compaction degree.According to the characteristics of the sand soil contains clay in this area,the orthogonal test scheme is designed with sandy soil with residual agricultural film as the test material.The effects of different moisture content(8%,10%,12%,14%,16%),different residual film content(0%,0.05%,0.1%,0.2%,0.3%,0.4%)and different clay content(10%,20%,30%,40%)on sand compaction density are studied.The results show that:(1)the adulteration of residual film had no effect on the optimal moisture content of sand;(2)The influence of residual film content on the dry density of sandy soil is affected by the clay content.When the clay content is very low,the residual film content has almost no influence on the dry density of sandy soil with residual film.When the clay content was between 10%and 20%,the dry density first increases and then decreases with the increase of residual film content.When the content of clay reaches 30%~40%,the dry density changes undulately with the increase of residual film content;(3)The dry density of sandy soil with residual film increases logarithmically with the increase of clay content,but this trend is affected by residual film content,and the higher the clay content,the more significant the influence.When the clay content is less than 20%,the dry density-clay content curves of sandy soil with different residual films almost coincide with each other and are larger than that of plain soil.When the clay content is greater than or equal to 20%,the dry density-clay content curve of sandy soil with different residual film contents is discrete.The dispersion is greater when the clay content is larger.