基于土体硬化模型的紧邻铁路基坑变形分析

Analysis of the Deep Excavations Deformation Close to the Existing Operating Railway Based on Hardening- Soil Model

研究目的:控制紧邻铁路运营线的深大基坑变形,是保证既有铁路安全运营的关键。在基坑数值分析中,其关键是选择合适的土体本构模型和计算参数。本文利用反分析的手段,通过将计算结果与现场监测数据进行对比分析,初步确定本工程采用的土体本构模型中主要岩土参数的数值,该方法对类似工程有一定的借鉴意义。研究结论:(1)利用反分析的手段,得出了本工程土体硬化模型高级刚度参数与土体压缩模量Es(0.1~0.2)的经验关系;(2)利用得到的参数,计算了基坑开挖引起的地面沉降量及围护桩弯矩值,与现场监测值及理正基坑计算结果吻合较好,目前该基坑工程已经完工,基坑围护结构保证了既有铁路安全运营的要求。(3)利用本文提出的反分析方法,通过土体压缩模量得到土体硬化模型高级刚度参数,对分析敏感环境条件下的基坑工程具有一定的参考价值。

Research purposes： The control of the deep excavations deformation close to the operating railway is the key to ensure the safe operation of the existing operating railway. In the numerical analysis of the excavations, it is critical to choose the suitable soil constitutive model and the calculating parameters. In the study of this paper, by using back analysis and comparing the calculation results with the on - site monitoring data, the access method of main geotechnieal parameter of the soil constitutive model in this project is primarily defined, which has some references value to similar projects. Research conclusions：（ 1 ） By using back analysis method, we get the empirical relationship between soil hardening model senior stiffness parameters and soil compression modulus Es^0 1-0.2^- （2） According to the existing parameters, the number of land subsidence and the bending moment of retaining wall are calculated, which are matched with the site monitoring value and the excavation calculation results. Now the deep excavation engineering has already been finished, and the excavation retaining structure ensures the safe operation of existing railways. （ 3 ） By using back analysis method mentioned in this paper, the soil hardening model senior stiffness parameters is received by the soil compression modulus, which has a certain reference value when analyzing excavation under sensitive environmental conditions.