Research On Polymer Pavement Materials And Road Structure Design In Open Pit Mines

In China,the single bucket truck mining process is mainly used in open-pit coal mines,with transportation costs accounting for about 60% of the total production costs.High-quality transportation roads serve as the foundation for the efficient,low-cost,low failure,and low accident operation of mining trucks.Geopolymer materials,as a binder for hardening open-pit mine transportation roads,can ensure that the road strength and traffic speed meet the use requirements,and construction costs are relatively lower.They are expected to be environmentally friendly,efficient,and economical mine road building materials for large-scale application in the future.The basic mechanical properties of geopolymer materials are investigated through the comprehensive application of mining system theory and methods,open-pit mine line engineering,rock mechanics,and damage mechanics theory and methods,as well as laboratory tests,numerical simulation,and theoretical derivation of mathematical models in designing pavement structures in open-pit mines.The thesis studies the main issues such as the influencing factors on the internal mechanical characteristics of rigid pavement slabs in open-pit mines and the verification methods for the mechanical structure of pavement slabs.The characteristics of road structures and service objects in open-pit mines are compared and analyzed in the thesis.The static axle load and dynamic vibration load characteristics of large mining dump trucks are studied,and a mechanical model for the rigid pavement structure of transportation roads in open-pit mines is established.The road structure of open-pit mines is relatively simple,with low comprehensive service intensity compared to airport runways and ordinary highways.The pressure of the dump truck on the road surface under static state with a full load is about 0.5MPa,and the maximum pressure under no load is about 0.3MPa.The maximum tire pressure of a dump truck in a running state is 1.6 times that of a stationary state.The mechanical properties of geopolymer paste concerning regular materials,fiber materials,polysaccharide materials,and chemical additives are studied using uniaxial compression tests and interfacial shear tests.The destruction process of slag geopolymer is mainly characterized by elastic deformation.Fiber materials and silicon aluminum-based additives can significantly improve the mechanical properties of geopolymer.The destruction mode of geopolymer paste is changed by fiber additives,leading to significant plastic deformation during the destruction process,and fiber materials as additives improve the interfacial adhesion strength to varying degrees.A two-dimensional PFC model composed of a geopolymer material surface layer,gravel layer,and rock base layer is established(20m × 4m),simulating the mechanical response of the dump truck to the interior of the road structure during operation and analyzing the impact of different wheel loads and different road junctions on the mechanics of the underlying polymer pavement.The response of dump trucks on the road surface of the road panel is a stress mode in which the top of the road panel is compressed,the bottom of the road panel is tensioned,the middle part sinks,and both ends are warped.The maximum tensile stress at the bottom of the road panel occurs at the tire measured on the rear axle of the heavy-duty dump truck,which is 0.7MPa.The elastic modulus of pavement materials is the factor that has the greatest impact on the tensile stress at the bottom of the road panel.A linear fatigue cumulative damage model for open-pit mine roads is proposed by considering the load stress distribution of road slabs and the dynamic load of trucks based on the Palmgren-Miner linear fatigue cumulative damage theory.This model provides a basis for the optimal design of rigid pavement structures in open-pit mines.There are 68 figures,18 tables,and 79 references in the thesis.