隧道初期支护的钢拱架与钢格栅选择研究

围岩条件较差情况下,复合式衬砌隧道一般采用钢拱架或钢格栅与喷射混凝土及锚杆组成的初期支护.但基于同样设计形式,钢拱架和钢格栅两种支护形式在经济、刚度、承载力等方面存在明显的差别.因此,比选二者适用时机和适用条件具有重要的实用价值.文章以广州龙头山单洞四车道隧道为研究背景,首先分析现场监测数据,得到钢拱架支护形式下的初始释放荷载规律;其次分析两种支护结构承载力随时间的变化规律,结合实测荷载释放规律对比和验证了二者的选择条件;文章最后给出了钢拱架与钢格栅的适用条件,并结合龙头山隧道给出具体意见.文章旨在为初期支护设计及施工过程中的支护参数优化提供借鉴和参考.

Study on Selection of Section-steel and Grid-steel in Primary Support System of Tunnel

Section steels such as H,I irons or grid-steel will be used as important materials in primary support system of tunnel with composite lining when the surrounding rock is too bad.However,there are obvious distinctions between the primary support system with the section-steel and the grid-steel system on stiffness,economy and bearing capacity.Therefore,it will be very useful and valuable to find the applicability for these systems.Based on Longtoushan road tunnel with four lanes in each separated cavern,the regularity of prime release load which acts on primary support system during construction with drift method on both sides is found by means of analyzing the data of measurement,firstly.And then,the authors concentrate on study of the bearing capacity of support system with time.Finally,the authors validates result of research on selection from two primary support systems with contrasting results between the first part and the second.It has the great value for design and optimization of parameter of support system during the construction of tunnel.