铁路隧道初期支护极限位移的意义及确定

阐述了隧道支护系统极限位移的意义,系统地介绍了初期支护极限位移的确定方法。采用连续体模型,按铁路隧道衬砌标准设计采用的断面形式和材料参数,对各级围岩中不同埋深条件下铁路隧道初期支护极限位移进行计算模拟,并对计算结果进行统计处理,与允许位移进行比较,单、双线断面相对位移分开,拱顶下沉、拱脚水平位移和墙脚水平位移设不同判据,采用修订前规范所列的埋深档次,确定档次范围值,最后综合确定出一套适于当今铁路隧道位移判别的极限位移数据。

CONCEPT AND DETERMINATION OF LIMIT DISPLACEMENTS OF PRIMARY SUPPORT SYSTEM OF RAILWAY TUNNEL

Concept of limit displacements of primary support system of railway tunnel are presented,and the method for determining the limit displacements is introduced systematically. The continuum model is adopted,and the cross section pattern and the material properties are used according to the design standard for railway tunnel lining. The limit displacements of the primary support system of railway tunnels are simulated and calculated for the tunnels of different depths in surrounding rocks of different classification. The calculation results are further treated in a statistical manner and compared with the allowable displacements. The limit displacements for single track tunnels and for double track tunnels are discriminated. Criteria are established respectively for crown settlement,horizontal convergence at arch springer and at wall foot. The depth ranges in the original codes are adopted,and the displacement range values are determined by combining the two sets of limit values. A series of limit displacement data are finally determined synthetically,which are consistent with the current displacement criterion for railway tunnel stability.