掺灰改良城市弃土路基填料CBR性能研究OA

Taking a certain highway subgrade filler(e.g.excavation soil of urban residential foundation pit)as the research object,this study conducted systematic laboratory and field tests on the CBR strength characteristics of lime-treated urban waste soil.The results show that:the CBR value of lime-treated urban waste soil is significantly improved and meets the specification requirements for subgrade filler CBR;at the same water content,the CBR value of the treated soil increases with the proportion of lime dosage;at the same lime dosage,the CBR value first increases and then decreases with increasing water content,and there exists an optimal water content for maximum CBR;the water immersion linear expansion rate of the treated soil is significantly reduced;at the same lime dosage,the difference between dry densities before and after water immersion,as well as the difference between wet densities before and after water immersion,both gradually decrease with increasing water content;the lime-treated urban waste soil exhibits high CBR strength and good water stability,making it suitable for use as subgrade filler.The optimal lime dosage needs to be comprehensively determined based on the characteristics of the urban waste soil,the improvement objectives,economic factors,and the results of laboratory and field tests,with a recommended optimal lime dosage of 4%.