基于实测松动圈的扩展卡尔曼滤波位移反分析方法

Displacement-based back analysis method using extend Kalman filter considering excavation damaged zone

基于现场松动圈实测结果,采用双重介质模型来考虑松动圈的影响,将施工中岩土体系统的反应看作动态随机过程,采用扩展卡尔曼滤波与离散元数值耦合方法对鹧鸪山隧道特定断面的现场监测数据进行跟踪反演,探讨观测误差与模型误差对滤波过程及参数识别结果的影响。研究结果表明:该方法得到的围岩力学参数具有历时性,可以反映洞室开挖后围岩力学行为的动态变化,从而可以更加及时地了解围岩的稳定状况;从误差分析来看,模型误差的取值对结果的准确性影响较大,而观测误差的取值对结果影响较小。因此,在实际操作过程中,要特别注意模型误差取值的准确性。

Based on the field-measured result of the excavation damaged zone（EDZ）, the extended Kalman filtering DEM coupling back analysis method,which adopts dual media model to consider the impact of broken zone and regards the reaction of rock system as a dynamic stochastic process during construction, was established and was applied to a specified section of Zhegu mountain tunnel. The effect of observation error and model error on the filtering process and parameter identification results was discussed. The results show that the mechanical parameters obtained by this method has a diachronic characteristic, which can reflect the dynamic change of the mechanical behavior of rock after excavation, and can be more timely to understand the stability situation of surrounding rock. From the identification results, the model error has a greater impact on the outcome than the observation error, Therefore, in actual operation, particular attention must be paid to get the accurate model error.