基于冲击夯下的回填土填料改性研究

Research on Modification of Backfill Soil Filling Based on Impact Ramming

对基于冲击夯下的回填土夯实的填料进行改性处理,研究了水泥、石灰和粉煤灰配比对路基填料最佳含水率、最大干密度、粘聚力、内摩擦角和无侧限压缩强度的影响。结果表明,4种改性土的最佳含水率都高于素土,且最佳含水率从高至低顺序为:S4>S1>S3>S2。改性土的最佳含水率都相较素土有所增加,而最大干密度有所减小,最大干密度从大至小顺序为S3>S4>S2>S1。改性土的28d粘聚力明显高于7d粘聚力,且改性土粘聚力从大至小顺序为S4>S3>S2>S1,且都明显高于素土;S3改性土的内摩擦角最大。随着龄期从7d增加至28d,素体和改性土的无侧限压缩强度都有不同程度提高;改性土的7d和28d无侧限压缩强度都明显高于素土,且改性土的7d和28d无侧限压缩强度从高至低顺序为S4>S3>S2>S1。

Modified fillers based on rammed backfills under impact ramming were performed,and the effect of the ratio of cement,lime and fly ash on the optimum moisture content,maximum dry density,cohesion,internal friction angle and unconfined compressive strength of subgrade filling is studied.The results show that the best moisture content of the four modified soils is higher than that of the plain soil,and the best moisture content from high to low is S4>S1>S3>S2.The best moisture content of the modified soil is higher than that of the plain soil,but the maximum dry density is decreased.The order of the maximum dry density is S3>S4>S2>S1.The 28d cohesion of the modified soil is significantly higher than that of the 7d,and the cohesion of the modified soil is S4>S3>S2>S1,which is obviously higher than that of the plain soil;the internal friction angle of S3 modified soil is the largest.With the increase of age from 7d to 28d,the unconfined compressive strength of both plain and modified soil increased in varying degrees;the 7d and 28d unconfined compressive strength of modified soil was significantly higher than that of plain soil,and the order of 7d and 28d unconfined compressive strength of modified soil from high to low was S4>S3>S2>S1.