The Development Of Shotcrete Equipment In The Tunneling Simulation System

In recent years,the continuous improvement of China’s infrastructure construction capacity has accelerated the development and utilization of underground space and resources.However,with the increase of buried depth,rockburst disasters occur frequently,posing threats to the personal safety of construction personnel and causing significant economic losses.This topic comes from major scientific instruments development project of national natural science fund: Deep Roadway/Tunnel Dynamic Disaster Physical Simulation Experiment System(project number: 51427803),an important equipment of its supporting subsystem.Spraying concrete way of mud on the surface of a tunnel effectively improves the strength and stiffness of the surrounding rock,ensuring the safety and stability of the tunnel project and reducing the occurrence of dynamic disasters such as rockburst.After studying the literature related to this subject from home and abroad,the research content is planned.According to the condition of shotcrete equipment in tunnel excavation simulation system requirements and technical indicators,the process of the shotcrete equipment is designed and the work of the shotcrete equipment is divided into continuous spraying stage and fixed spraying stage.According to the functional requirements,the shotcrete equipment structure is selected.The overall structures include: spray gun mechanism,rotating mechanism,support mechanism,and feed mechanism.The mechanical simulation analysis of the key mechanism proves that the mechanism can meet the requirements of design and working conditions.According to the requirement of the spraying robot,we selected the corresponding type of spraying machine and motor.The core research content of this subject is the influence of spray gun parameters on coating.In order to improve the quality of coating,this paper mainly studies the relationship between spraying elevation Angle,nozzle length,and motion trajectory distance and coating.According to the actual parameters of the shotcrete equipment,a mathematical model was established to analyze the relationship between the parameters of shotcrete gun and the shape of coating.The accumulation rate of coating was studied by the elliptic double distribution model.Only when the shotcrete equipment works at a reasonable spraying rate could the coating thickness be uniform.The coating overlap was simulated and analyzed by Scilab software,and the reasonable trajectory spacing was obtained,and the matching relationship between the rotation speed and the traveling speed of the spray gun was determined.Fluent software was used to conduct simulation analysis of the nozzle’s internal and external flow field,verify the theoretical model analysis conclusions,and provide help for subsequent experiments.According to the work requirements,the control system of shotcreting robot is designed,and the corresponding hardware equipment is selected.The mathematical model of DC servo motor position control is established,and the control system is simulated and analyzed by MATLAB / Simulink.In order to improve the performance of the system,the conventional PID control is selected as the control strategy of the system.In view of the above theoretical study and verification of shotcrete equipment performance,an experimental platform was set up and the experimental study of shotcrete equipment was carried on,including visual experiment,spring variable diameter,motion control experiment and spraying experiment.According to the experiment data,the shotcrete equipment in the tunneling simulation system meets the design requirements and can complete tunnel shotcrete support task.