Full-Scale Grouting Model Test Of Box Girder Prestressed Pipelines And Simulation Of Meshless Method

As the main method of geophysical surveying,ground penetrating radar is widely used in the field of non-destructive testing in engineering because of its high efficiency,rapidness,and non-destructive characteristics.In the current project,most of the tests for the grouting plumpness of box girder prestressed pipelines still use the drilling method.Therefore,this paper applies the ground penetrating radar to the grouting plumpness model test of the box girder prestressed pipe.The main purpose is to use the ground penetrating radar.The application of model detection to the actual box girder can prevent and reinforce the defects of the box girder prestressed pipe grouting such as plumpness,so as to reduce the problems caused by the deformation of the box girder and the lack of bearing capacity.Finally,based on the improved sarma and transmission-absorption boundary conditions,the meshless Galerkin method is used as a theoretical basis to simulate the grouting plumpness of the box girder prestressed pipe model.This method does not require meshing,and only discrete nodes are needed.The limitation brought by the grid is simple in form and wide in adaptation range.Then the sliding point least square method(MSL)is used to fit the field function,the penalty function method is used to deal with the gridless boundary conditions,and the effective weight function and basis function are selected;the influence is reasonably determined.For the radius,the boundary of the contact surface of the model is treated with different absorption boundaries.The main research contents and results are as follows:1 Ground Penetrating Radar Model Detection Test Analysis on Grouting Fullness of Box Girder Prestressed.Since the thickness of the box girder floor and the left and right webs are basically below 50 cm,the ground penetrating radar antenna frequency is 1600 MHz.After research and analysis,the image resolution detected at the antenna frequency of 1600 MHz has higher precision,and the three-dimensional map intuitively reflects the fact that the pipe grouting is not sufficient.2 In this paper,the meshless Galerkin method based on the sliding least squares method is used.After analyzing various weight functions,the negative exponential weight function and the quadratic basis function are used.The fourth-order Gaussian integration is used for numerical integration.The penalty function is used as the first type of boundary condition in the meshless Galerkin method.In order to make the model simulation closer to the actual project,the transmission and improved sarma absorption boundary conditions are used to absorb the electromagnetic waves at the boundary and corner of the model respectively.deal with.3 Compile the MATLAB element-less Galerkin method forward program based on the transmission-absorption boundary conditions and the improved absorption boundary conditions of the sarma,and perform the forward simulation on the model,study and analyze the simulated image,and obtain the circular cavity.The simulation results are arc-shaped,and the transmission and absorption boundary conditions are relatively good for the strong reflection and absorption of the corner points of the model,and then the double voids at the same level are simulated using the meshless program based on the transmission and absorption boundary conditions.The simulation result signal has two arcs and cross each other.4 The matlab numerical simulation results of the meshless Galerkin method and the model test results are compared with each other.The results of the void simulation and test detection are all arc shapes,fully verifying that the meshless Galerkin method forward simulation is applied to the ground.The feasibility of radar grouting plumpness detection.