隧道局部支护与系统支护判别标准及方法研究

Study on the Criterion and Method for Distinguishing Local Support and Systematic Support of Tunnel

目前,隧道工程支护结构以系统支护为主,缺乏对局部支护的研究和应用。为实现隧道支护结构的合理化设计,基于隧道无支护开挖后的围岩破坏区分布特征,研究局部支护和系统支护的划分标准与方法,得到以下结论:(1)研究确定将隧道开挖后边墙区域深度大于1 m、拱部深度大于0.5 m的破坏区作为隧道潜在塌方区域,并将此作为支护对象;(2)当隧道无潜在塌方区域时,判定隧道自稳,即设计断面小于临界稳定断面,无需支护;拱墙潜在塌方区域占比小于30%,可采用局部支护方案;拱墙潜在塌方区域占比在30%~60%,可采用分区不等强支护;当拱墙潜在塌方区域占比大于60%时,需采用等强系统支护。

At present,the support structure of tunnel engineering is mainly system support,lacking of research and application of local support.In order to realize the reasonable design of tunnel support structure,this paper studies the classification standard and method of local support and system support based on the distribution characteristics of surrounding rock failure area after tunnel excavation without support,The conclusions are as follows:(1)the damaged area with the depth of side wall greater than 1 m and arch greater than 0.5 m after tunnel excavation is determined as the potential collapse area of the tunnel,and this area is taken as the support object.(2)When there is no potential collapse area in the tunnel,the tunnel is regarded self stable,that is,the design section is smaller than the critical stable section,and no support is needed.If potential collapse area of arch wall accounts for less than 30%,local support scheme can be adopted.If the proportion of potential collapse area of arch wall is between 30% and 60%,unequal strength partition support is employed.In case that the potential collapse area of arch wall accounts for more than 60%,equal strength support system is required.