富水砂层刚度参数敏感性分析及地表沉降预测*

为了在富水砂层地铁盾构施工中保证施工安全，控制地表沉降是其重要措施。依托福州地铁盾构工程项目，利用正交试验方法，使用有限元软件Plaxis 3D建立25个数值分析模型，采用反分析的方法，确定富水砂层土体硬化模型(Harding Soil model)主要刚度参数之间的关系；通过对各刚度参数进行极差分析与方差分析，确定土体硬化模型各刚度参数敏感性和显著性，建立刚度参数与地表沉降的数学模型。研究结果可以较好地对最大地表沉降进行预测，为富水砂层参数优化和盾构施工地表沉降预测提供理论基础。

Sensitivity analysis of stiffness parameter and prediction of ground settlement for watered sandy stratum

In order to ensure the construction safety of metro shield construction in the watered sandy stratum,controlling the ground settlement is an important measure.Based on the shield construction project in Fuzhou Metro,25 numerical analysis models were established by using the finite element software PLAXIS 3D with the orthogonal test method.The relationship between the main stiffness parameters of the hardening soil model for the watered sandy stratum was determined by using the back analysis method.The range analysis and variance analysis of each stiffness parameter were conducted to determine the sensitivity and significant of each stiffness parameter in the hardening soil model.Finally,a mathematical model of stiffness parameters and ground settlement was established.The results can predict the maximum ground settlement better,and provide theoretical basis for the parameters optimization of watered sandy stratum and the prediction of ground settlement in the shield construction.