Compaction Technology Comparison Analysis And Compaction Quality Inspection Technology Research For Fine Sand Roadbed

Sandy soil has the advantages of strong stability,good water permeability and fast settling speed,and it often uses sandy soil for subgrade filling.But it is not easy to compaction and application because of its low cohesion,particle size uniformity and compactness.In view of the technical problems of the loose and compactness of sand soil,for the widely distributed silty sand filler along the Shen-Xi industrial Corridor from the Liaohe River basin to the Bohai Railway,the simulated compaction test of three kinds of plate plates in fixed point and step moving drop hammer under impact load was carried out respectively based on the small size sand box model.The evolution characteristics of soil displacement,compactness and bearing capacity in compaction process are obtained,and the influence of compaction mechanical-soil contact form on compaction effect and the trend of compaction energy are analyzed,which provides the test basis for perfecting compaction technology of silty sand filler.The K₃₀ test of foundation coefficient is an important control parameter and detection method for the construction quality of railway subgrade in our country.It is very important to study the K₃₀ test of the railway subgrade with silty sand and to carry out the compaction quality test reasonably and efficiently.In view of the lack of cohesive force of silty sand filler and in the case of loose surface and low carrying capacity,by constructing the unit structure fill model,carrying out the fine K₃₀ test of silty sand subgrade under different constraint conditions,analyzing the relationship between the foundation coefficient and the different constraint states,a K₃₀ detection method is proposed,which is suitable to the working state.The research foundation is provided for optimizing the K₃₀ detection technology of silty sand filler.The main work and results of the study are as follows:?1?According to different gradation and fine particle content of silty sand filler,the physical and mechanical properties are tested,and the classification method of silty sand filler based on compaction performance of subgrade filling construction is put forward.?2?For the construction of poor compaction properties of silty sand filler,in this paper,the simulation model of filling compaction is constructed.Combined with the results of compaction test on site subgrade,a set of indoor simulator is developed,which reflects the effect of compaction mechanical-soil contact form on the compaction effect of silty sand filler.The compaction method and construction technology for increasing the grinding quality of silty sand are put forward.?3?The K₃₀ test of foundation coefficient under different boundary conditions for bearing plate is carried out.The paper developed the auxiliary equipment suitable for the compaction quality testing of silty sand subgrade,innovated the test method of K₃₀ test for the foundation coefficient of silty sand subgrade,and formed the compaction control and detection technology of silty sand subgrade.The research results can be widely applied in the construction of new railway projects along rivers and coastal areas such as Liaohe river basin,Changjiang and Zhujiang river delta,Jiangxi-FU alluvial plain,etc.,which can save the construction cost,guarantee the quality of the project and have a broad application prospect.