An Experimental Study Of Engineering Properties Of Cement Kiln Dust-Treated Loess

Loess is one of macroporous and weak cemented Quaternary sediments,However,due to the loess with porous,easy to disintegrate,easy to collapse and poor water stability and other defects,easily lead to ground subsidence,ground cracks and landslides and other geological disasters and the whole building or part of the uneven settlement and other engineering problems.For high-speed railway,trafficway and other high standard projects,the lower constitution of loess can not be directly used as subgrade filling.In order to solve this problem,it is necessary to improve the Loess with poor mechanical properties.In this paper,by summarizing the research results of predecessors,we use of cement kiln dust(CKD)as curing agent for loess modification.The basic property test,engineering property test,microstructure and material composition test of CKD compacted loess samples were carried out respectively.By studying the engineering characteristics,microstructure and material composition of loess with CKD improvement,exploring the suitable dosage range of CKD improved loess,and analyzing the amelioration mechanism of CKD on loess improvement,which provided the theoretical basis and application value for the construction of foundation engineering in loess area.The results show:(1)After the Loess improved by CKD,its water stability,shear resistance and unconfined compressive strength are improved,and the compressibility and collapsibility are reduced.(2)The collapsibility of loess can be eliminated by the test when the proper amount of CKD is more than 27%.When the content of CKD is more than 15%,the shear strength and compressive strength of the Improved Loess tend to be gentle.(3)After the Loess improved by CKD,the total pore volume of loess is decreased,soil pore type and soil particles connections are changed,thus the loess structure became dense and interparticle connection point more firmly difficultly to slip or damage.The characteristics of microstructure change regulation is from large pore structure to inlaiding microporous semi cemented structure,eventually it has clot cementation structure.