基于强度折减法的小净距隧道合理净距的探讨

Discussion on Reasonable Distance of Small Interval Tunnel Based on Intensity Discount Method

由于连拱隧道的工程造价、施工难度、施工周期均比双线隧道大得多,所以在工程中产生了一种新的结构形式——小净距隧道。在小净距隧道的设计过程中,中间岩柱的宽度对于隧道的稳定性和工程整体造价有着相当大的影响。影响小净距隧道合理净距的因素很多,比如围岩级别、结构形式、施工工艺等。使用传统的力学计算法和力学试验,很难得出综合各种因素的计算结果,采用有限元模拟的方法和强度折减弹塑性有限元方法则可以计算各种复杂情况下围岩的应力、变形、塑性区分布等情况,从而确定小净距的合理净距。

Project cost,construction difficulties and construction cycle of double-arch tunnel are more than two-lane tunnel,and small interval tunnel has appeared.In the design of the tunnel in a small clear distance process,the width of the middle pillar has considerable effect on tunnel stability and project cost.Factors such as the rock-level,structure,construction technology have effect on reasonable distance,it is difficult to draw comprehensive result of various factors by traditional mechanical calculations and experiments.Using the finite element simulation methods and elastoplastic finite element method for strength reduction can calculate rock stress,deformation,plastic zone distribution under different complex conditions which can determine the reasonable small clear distance according to the results of the analysis.