研究目的: 在北京地区某高铁大型高架站桥施工过程中,应用改进精细分层总和法快速分析预测对临近高铁桥墩的沉降影响。首先基于圣维南原理,将高架站桥的竖向荷载分解为一系列不同位置和不同深度的矩形平面荷载,采用Mindlin解计算附加应力值,然后采用土体硬化模型模拟土体的压硬性并拟合压缩模量,进一步采用等代墩基法进行沉降影响计算,土层计算厚度为0.1~1.0 m。分别采用有限单元法和现场实测数据对算法验证后,对后续施工的沉降影响进行预测,提出平衡浇筑法和堆载配重法用于控制对既有桥墩的不均匀沉降影响。
研究结论: (1)本文算法的计算时间为同等规模有限元模型的1/14,与实测数据的最大绝对误差为0.94 mm,相对误差为12%,满足工程要求;(2)提出的施工控制措施合理有效,具有较强的实用性,可为类似工程提供借鉴和参考。

Research purposes: The modified fine layering summation method is used to predict the influence of construction of a large elevated station on the settlement of adjacent piers of high-speed railway in Beijing area, realizing the rapid prediction of settlement influence in construction process. First, based on the Saint Venant's Principle, the vertical load of the elevated station bridge pile foundation was simulated as a rectangle load with different positions and depths, and additional stress value was calculated using the Mindlin solution. Then, the soil hardening model is used to simulate the compressive stiffness of the soil and fit the compressive modulus. The equivalent pier method is further used to calculate the settlement effect. The calculated thickness of soil layer is 0.1~1.0 m. After verifying the algorithm with finite element method and field measured data, the settlement influence of subsequent construction was predicted, and balanced casting method and stack-load balancing method are proposed to control the influence of uneven settlement on the existing bridge.
Research conclusions: (1) The proposed algorithm required 1/14 of the calculation time of a finite element model of the same scale, and the maximum absolute error is 0.94 mm with the measured data, and the relative error is 12%, which meets the engineering requirements. (2) The construction control measures proposed are reasonable and effective, and have strong practicability, which can provide a reference for similar projects.