Study On The Influence Law Of Hydraulic Crushing Concrete Parameters And Damage Prediction Model

Cement concrete materials are often widely used in the transportation civil construction industry because of their composition of raw materials,simple production process,wide adaptability,structural rigidity and other excellent properties,however,cement concrete pavement is difficult to overcome the defects of hydration,dry and wet and cold and heat alternation and other shrinkage deformation generated by cracking,in the natural environment and the repeated action of the vehicle,the service life of its materials is limited,which leads to the renovation and reconstruction of the pavement structure,etc.Increased demand.Concrete crushing and demolition will be one of the important tasks of pavement repair and maintenance work,and the traditional way of using pendulum hammer,wind pick and planer to crush concrete has problems such as noise vibration,dust pollution and energy consumption,so a hydraulic crushing technology with the advantages of environmental protection,no dust and no thermal effect plays an important role in the crushing and demolition work of cement concrete pavement.The basic principle of hydraulic crushing technology is to convert the tap water into jet water spray through high pressure device,using the jet water pressure to achieve the purpose of cracking broken materials,and thus has a broad application prospect in the process of cement concrete pavement renovation and maintenance.However,hydraulic crushing technology involves complex issues such as fluid-solid coupling,large impact deformation and damage evolution,and there are many factors affecting the effect of hydraulic crushing damage,and engineers often adjust the parameters according to their experience in the process of breaking operation,resulting in a large variation in the breaking effect of hydraulic crushing technology,which seriously affects the development of its technical efficiency and high precision application.Therefore,in order to meet the requirements of more efficient and accurate hydraulic breaking concrete,the study optimized the multi-dimensional parameters of hydraulic breaking concrete based on orthogonal design tests,and analyzed the damage characteristics of concrete under the action of hydraulic force by combining numerical models,and finally developed a set of algorithm analysis system for hydraulic breaking concrete by using machine learning algorithm model and Python language.The main results obtained from the study are as follows.(1)Based on the orthogonal design method,the mechanical test of concrete and the test of hydraulically crushed concrete were conducted,and the influence law of multi-dimensional parameters such as pump pressure,target distance,concrete strength and crushing time on concrete crushing index was explored,and it was found that the influence of pump pressure and crushing time on concrete crushing index was always positive,and the variability of the influence of different grades of concrete on crushing index was great,and the resistance of higher strength concrete to the influence of the target distance on the crushing index always shows a trend of increasing first and then decreasing.According to the results of the extreme difference analysis,the parameters affecting the concrete crushing index were optimized,and the hydraulic parameters with better economy for hydraulically crushed concrete were also proposed,and the weight relationship of the influence of multidimensional parameters on the concrete crushing depth was derived as follows:pump pressure>concrete strength>target distance>crushing time;the weight relationship of the multidimensional parameters affecting the concrete crushing diameter was as follows:pump pressure>target distance>concrete strength>crushing time.The weight relationship of multidimensional parameters on concrete crushing volume is:pump pressure>concrete strength>target distance>crushing time.(2)A hydraulic impact concrete model was established using the SPH-FEM coupling method,and the numerical model was verified qualitatively and quantitatively based on CT scan tests.The study used image processing technology to propose a comprehensive damage factor for concrete to characterize the degree of damage and destruction of concrete,and found that the damage and destruction of concrete is most serious in the hydrodynamic region,and the further away from the hydrodynamic region,the weaker the concrete is affected by the hydrodynamic impact.The liquid-solid contact area of concrete is prone to stress concentration,and the two corners of the concrete surface and the bottom center region are not subject to the effect of equivalent forces,when the concrete damage accumulates to a certain extent and the equivalent force reaches a certain peak,the concrete particles will completely fail.(3)The prediction model of hydraulically broken concrete was built by using Random Forest algorithm,Ada Boost algorithm,GBDT algorithm,XGBoost algorithm and Light GBM algorithm,and based on the comparison of fitting coefficient R~2,root mean square error RMSE and mean absolute error MAE,the algorithm model with higher prediction accuracy and Python language was used to develop the hydraulic broken concrete The algorithm analysis system for hydraulically crushed concrete was developed using the algorithm model with high prediction accuracy and Python language,and the interface interaction of the system window and the prediction function of concrete crushing index were successfully implemented.