Research On Construction Technology Of Iron Tailings Subgrade Of Yanchong Expressway

In the past,open mining of mineral resources caused a large number of tailings stockpiles,of which iron tailings stocks accounted for about 1/3 of the total stockpiles,and they have increased year by year with the mining of iron.The storage of iron tailings will cause adverse effects such as waste of land resources,destruction of ecological environment,and induced geological disasters.Nowadays,the rapid development of expressways has caused a shortage of building materials.The piled iron tailings have solved the problem of material shortage,and solved a series of problems brought by the piled up,protecting the environment and creating good economic and social benefits.This article takes the filling of the Yanchong Expressway subgrade under construction as the research background.Highway roadbed filling requires a lot of filling materials,and iron tailings storage along the project can provide sufficient filling materials.The quality of expressway roadbeds is high.Based on the project,a large number of indoor and outdoor tests are used to analyze and study the iron tailings to fill the highway roadbed.The research content and results mainly include the following aspects:1.Physical and mechanical properties of iron tailings.The iron tailings in this area are obtained through a laboratory test and the particles are well-graded fillers.The optimal moisture content and maximum dry density of the fillers are obtained.The shear strength and dynamics of the iron tailings are obtained using a coarse-grained soil triaxial test The rebound modulus and analysis of the strength of iron tailings are formed by the combined effect of its own strength and structural characteristics.Finally,it can be seen that the filler meets the requirements of highway fillers.2.Subgrade treatment method and stability analysis of iron tailings under complicated conditions.The iron tailings subgrade in special sections is filled with different treatment methods under different conditions.The collapsible loess foundation and the high-filled subgrade are all dynamically compacted.The filling and digging junction is a combination of open steps and reinforcement..3.Research on construction technology of iron tailings subgrade.The first bid test section is set in the construction bid section.Through the test section construction,key construction parameters such as the loose paving thickness,equipment combination,and rolling technology of the highway subgrade to fill the highway foundation are obtained.In-depth study of on-site process and quality testing technology of roadbed surface,using the traditional process detection method to obtain the standard value of the test and the correlation between the two traditional detection methods,and obtaining the test section roadbed filling through the roadbed surface testing completely in line with the design requirements,indicating the use of research The obtained construction technology can make the iron tailings roadbed meet the compactness requirements.4.Research on rapid detection method of iron tailings subgrade.The traditional quality inspection methods used in the roadbed filling process and roadbed surface inspection have some problems such as damage to the roadbed structure,complicated operation process and long test time.PFWD and soil modulus/stiffness meter are two new fast non-destructive testing methods.By studying the equipment composition,testing principle,testing procedure and testing stability analysis of the two methods,we can know the feasibility of the two testing methods in actual testing.The two quick detection methods are combined with the traditional detection methods to test the subgrade quality of the test section.The regression analysis method is used to establish a correlation between the two detection methods and the traditional detection methods,and the standard values of the two detection methods for the iron tailings roadbed quality are obtained.