为准确预测洞桩法导洞开挖引起的地表沉降，针对直墙圆拱断面及多导洞施工特点，对传统随机介质理论方法进行改进，通过几何分解与应力场分析，推导了适用于直墙圆拱断面的积分界限解析式，并将Sagaseta地层损失公式引入随机介质理论框架，建立了考虑断面几何特性的地表沉降预测模型。通过广州地铁工程实例与有限元算例验证，结果表明：与传统方法相比，改进模型的计算结果与实际监测值及数值模拟结果的相对误差分别降至15.2%和66.2%，均显著优于传统模型；同时，该方法参数简单、计算效率高，能够有效反映多导洞叠加效应及直墙圆拱断面的地层变形规律。研究成果可为洞桩法施工的沉降控制与安全评估提供理论支持。

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.