| In mountainous and hilly areas,in order to protect the natural environment,increase economic benefits,and rationally use the land,the method of “digging mountains and filling ditches” is often used to build high-grade highways,and embankments are filled with soil and rock produced by tunnel excavation and cutting blasting.High-filled embankments are widely used in mountainous and hilly areas.Based on an Expressway Project,this paper studies the road performance of the soil-rock mixtures and shows that its performance soil is closely related to rock content,and fillers with appropriate rock content can be used for filling high embankments;At the same time,based on the construction technology of dynamic compaction used in the project,combined with field test and numerical simulation analysis,the effect of dynamic compaction of the high-filled embankment is discussed,and the rapid construction technology of high-filled embankment is optimized.The main research contents and results are as follows:(1)The fillers of different filling sections of the project are selected to carry out basic physical characteristics tests such as particle analysis.It is believed that the dynamic impact method can break and compact the soil with dynamic impact,which can improve the particle gradation of the filler and help To improve the quality of embankment filling.(2)Prepare soil-rock mixture samples according to the rock content,and study the compaction characteristics and strength characteristics of the soil-rock mixtures through engineering mechanics tests,and obtain the engineering mechanical parameters of the soil-rock mixtures,such as maximum dry density,compressive modulus,CBR value,and expansion,unconfined compressive strength and shear strength,are closely related to the rock content,and the specific relationship between each parameter and the rock content is obtained through data fitting and other means,which provides a parameter basis for the numerical simulation research in the following.(3)Using ABAQUS to establish a dynamic compaction model,through comparative analysis of different working conditions,it is believed that the compaction hammer has a compacting effect on the lower and lateral soils,and part of the uplift is produced in the shallow soil around the ram pit.According to the characteristics of vertical displacement,horizontal displacement and vertical dynamic stress,it can be judged that the effective reinforcement depths of 2000 k N·m,4000 k N·m,6000 k N·m dynamic compaction are 5.5～6.2m,7.5～8m,9～9.7m respectively,the distance between the ramming points should not be greater than 3.5m,4.5m,and 5m respectively.(4)The 4.5m and 8m test sections of the loose pavement were set up on the site.The test data of reverse excavation showed that the compaction and bearing capacity of the embankment of the 4.5m test section are basically qualified.According to the engineering characteristics of the soil-rock mixtures,an optimized rapid construction method of “division and layered filling and dynamic ramming reinforcement” of the soil-rock mixed high embankment is proposed.The next layer can be constructed according to the optimized plan;In the construction of the next layer,staggering the ramming points of the upper and lower layers can effectively avoid the impact of the lack of compaction of the ramming edge,and achieve the purpose of rapid construction and economic safety of the high embankment filled with the soil-rock mixtures. |
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