考虑松动圈的卡尔曼滤波与有限元耦合反分析法及其在围岩稳定性分析中的应用

Kalman filtering & FEM coupling back analysis method considering broken zone and its application to stability analysis of surrounding rock

考虑洞室开挖后围岩的力学状态和岩石力学众多问题的不确定性本质,通过弹性模量折减的方法,建立了考虑松动圈的卡尔曼滤波与有限元耦合反分析法,并编写了相应算法程序。利用基于文件操作的Fortran与VC++交互通信技术,一方面,为隧道施工量测管理与围岩稳定智能分析系统增加了非确定性反分析模块;另一方面,也使反分析能够利用该系统的图形模块进行前后处理,使该方法的工程应用更加简单,为该法的应用推广创造了很好的条件。用反分析法求出围岩初始参数后,通过有限元正分析可求出全域最大剪应变,并与试验和理论推演获得的临界剪应变相比较,进而进行围岩稳定性判定。由于该围岩稳定性分析法摒弃了一般有限元正分析在围岩初始应力场上的不合理假设,因而结果更贴切实际,更具合理性。对白云隧道YK48+737断面的现场监测数据进行了跟踪反演,获得了该断面围岩塑性区历时变化图,从而及时地了解了围岩的稳定状况,指导了设计和施工。

Considering the mechanics status of the excavated surrounding rock and the uncertainty essence of many problems in rock mechanics, the Kalman filtering ＆ FEM coupling back analysis method considering broken rock zone is established and programmed in Fortran. Using the interactive communication technology between Fortran and VC＋＋ based on the operating files, the back analysis module is added into the Tunnel Construction Monitoring Management and Surrounding Rock Stability Intelligent Analysis Soitware System for one hand; and the back analysis and surrounding rock stability analysis is realized conveniently and visually based on the graphics module of the system developed by ourselves for the other hand. After the initial parameters have been worked out based on the Kalman filtering ＆ FEM coupling back analysis method considering broken rock zone, the maximum shear strains of the global calculating field are obtained based on FEM. And then, by comparing with the critical shear strain obtained by experiment and theoretical deduction, the stability of the surrounding rock could be judged. Because the method mentioned above discards the unreasonable hypothesis of the initial stress field, the results are more practicable and reasonable. The method has been successful applied to the Baiyun tunnel YK48＋737; and the changing plastic zone distribution figures through time are obtained. The on site designers and builders would be able to know the stability situation of the surrounding rock in time, and improve their design and construction.