| Coal gangue is a major subsidiary product in coal mining,with a rapid growth rate of more than 100 million tons per year.A large amount of coal gangue not only causes waste of land resources but also causes serious environmental pollution problems.How to turn coal gangue into waste,broaden the utilization of coal gangue,and improve its utilization rate has become an urgent problem.The application of coal gangue in the road base is still relatively few,and it is rarely reported in the airport field project.The navigable airport has the characteristics of low load level,short construction period,and good economy.If coal gangue can be applied to the field project of the navigable airport,it can not only solve the problem of gangue utilization,but also greatly save engineering costs.Good economic and social benefits.This article is based on coal gangue somewhere in Shaanxi.The main research and results are as follows:1.Through laboratory tests,basic physical,chemical,and mechanical properties such as particle size,density,disintegration resistance,chemical composition,loss on ignition,liquidplastic limit,and crushing value of coal gangue were obtained.It lays a foundation for studying the characteristics of coal gangue mixture and the applicability of airport engineering.2.The factors affecting the compressive strength of coal gangue mixture were studied through experiments,and the relationship between fine aggregate and 7d unconfined compressive strength was established.When the fine content was between 45% and 50%,the compressive strength of the mixture peaked;The 7-day unconfined compressive strength test,split strength test,and compressive rebound modulus test were performed on coal gangue mixtures with different cement contents to establish the relationship between the cement content and the three.When the cement content is greater than or equal to 5.5%,the strength performance of the coal gangue mixture meets the relevant requirements of the 2B pavement base course,and provides a design basis for the application of coal gangue in the field base course.3.The stability and durability of coal gangue mixture were studied experimentally.Through the wet and dry cycle test,freeze-thaw cycle test and fatigue test,the water stability,frost resistance and durability of coal gangue mixture were studied.The test results show that the water stability coefficient of coal gangue is about 0.9,and the residual strength can reach 62%-72% after 5 freeze-thaw cycles.4.Based on the test results and the finite element method,the applicability of the coal gangue mixture in the navigable airport was analyzed.Firstly,under the action of common navigable aircraft,the law of the mechanical response in the base layer under the conditions of the changes in the base layer modulus,thickness,and track base modulus under the conditions of the change of the base layer modulus,thickness,and track base modulus is analyzed.Then combined with the traffic volume and design life of the airport,the load-bearing performance and durability of the coal gangue base course were analyzed.The analysis results show that,based on the coal gangue material used in this paper,its road performance basically meets the requirements for the road base and semi-rigid base materials in the 2B airport field project.Based on the coal gangue material used in this study,the technical parameters of the semi-rigid base course at the airport are discussed.It is hoped that this research can provide a certain reference for the utilization of coal gangue and the construction of China's navigable airport. |
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