Experimental Study On Compaction Quality Controlling Of Cement Stabilized Macadam In High-speed Railway Subgrade

It is taken as the research background that is the high-speed railway subgrade in seasonal permafrost region,and cement stabilized macadam is taken as the research object.The laboratory tests are carried out to research the compaction properties(K30,Evd,Ev2,etc.)and engineering mechanical properties(unconfined compressive strength,modulus of resilience and CBR)of the cement stabilized macadam bed by factors such as grain composition and cement content.The related research parameters and technical indexes can be used to optimize the structural design of the surface of the bed,and to provide the basis for the design and construction of the high-speed railway subgrade.They also provide the basis for compaction performance evaluation and disease prevention and control,which is of great practical significance to ensure the safety and smoothness of high-speed railway subgrade and guide the construction of high-speed railway line.The main research contents and achievements are as follows.(1)A model device was developed to simulate the compaction condition of the foundation bed.The device can be used to test the compaction index in the laboratory,and the device can meet the design requirements from the test results.(2)The engineering mechanical performance test of grading macadam and cement stabilized macadam was carried out to analyze the test results.It was found that the 7d unconfined compressive strength,modulus of elasticity and modulus,CBR of grading macadam and cement stabilized macadam meet the needs of the project,and the cement stabilized macadam exhibits good mechanical properties,far exceeding the grading macadam under the same test conditions.(3)Compaction test of grading macadam and cement stabilized macadam samples was completed to obtain the results of compaction quality control indexes of these samples.The results show that the cement stabilized macadam bed has excellent compaction performance,and it has better compaction quality than the gravel base in the same compaction coefficient,and under the condition of 0.97 compaction coefficient,The compaction quality control index of the cement stabilized macadam bed is far more than the requirements of the current specification.(4)It is the influence of cement content and particle gradation on the performance and compaction performance of cement stabilized macadam foundation: the more cement content,the better the engineering performance and compaction performance;The larger the size range of the gravel particles removed,the worse the engineering mechanical performance and compaction performance.(5)Considering the relationship between the compaction performance indexes and the engineering performance index,analyzing their strengths and weaknesses,and it is recommend the engineering mechanical indicators to apply to the quality control for high-speed railway subgrade in seasonal frozen soil region.