In order to accurately predict the surface settlement caused by the excavation of the pilot tunnel by the hole pile method, the traditional stochastic medium theory method was improved based on the characteristics of the straight-wall arch section and the multi-pilot tunnel construction process. Through geometric decomposition and stress field analysis, an integral boundary analytic formula suitable for the straight-wall arch section was derived. The Sagaseta formation loss formula was incorporated into the stochastic medium theory framework. A surface settlement prediction model accounting for the geometric characteristics of the section was established. Through the Guangzhou subway engineering example and the finite element example verification, the results show that compared with the traditional method, the relative error between the calculation results of the improved model and the actual monitoring value and the numerical simulation results is reduced to 15.2% and 66.2% respectively, which is significantly better than the traditional model. At the same time, the method has simple parameters and high computational efficiency, which can effectively reflect the superposition effect of the multi-pilot tunnel and the stratum deformation law of straight wall arch section. The research results can provide theoretical support for the settlement control and safety assessment of hole pile construction.