Probability quantitative study on influence of newly-built concurrent engineering on existing high-speed railway track displacement

Concurrent projects are becoming more and more common within the existing high-speed railway land. In order to solve the problem that the reliability of the calculation results was difficult to evaluate due to the large discreteness of soil mechanical parameters in the process of calculating the impact of new parallel bridges on the displacement of existing high-speed railway tracks, a soil-bridge-track finite element model was established. The sensitivity of the track displacement change to the perturbation of soil mechanical parameters was calculated by the parameter sensitivity analysis method. The parameters with larger sensitivity coefficients were extracted, and the track deformation and sensitivity were obtained by the response surface method. Then, according to the probability distribution of soil layer parameters, the response surface function calculation was carried out, and the reliability of the calculation results was evaluated. The results are drawn as follows. Depending on the area where the project is located, the sensitivity coefficient of track displacement to the mechanical parameters of gravel clay and silty clay is relatively large. The influence of internal friction angle on track displacement is the most significant. The response surface function is evaluated, and the error between the predicted value of the high-speed rail track displacement response surface and the value calculated by the finite element model is within 1%. The response surface function can replace the finite element model to calculate the displacement of the existing high-speed rail track, with a confidence level of 95%. When calculating the variation of soil layer parameters, relying on the pier displacement of the project, the lateral displacement value of the pier top is 1.119 mm, and the vertical displacement value is-0.725 mm, and the reliability of the project is high. By fitting the finite element calculation results with the response surface, the calculation efficiency can be greatly improved. The probability quantile value of the existing high-speed rail track displacement calculation results considering the discreteness of soil parameters can be obtained, which can provide a reliable method for predicting the track displacement for similar projects in the future. © 2023, Central South University Press. All rights reserved.