轻型混凝土在马坞梁隧道明洞回填中的应用研究

Research on Application of Lightweight Concrete in Backfilling of Open Cut Tunnel in Mawuliang Tunnel

为解决回填明洞上部修筑改线道路存在荷载大的问题,以新建景礼高速陇南段马坞梁隧道为研究对象,对原设计普通混凝土材料进行轻型泡沫混凝土置换,运用数值模拟的方法对3种不同轻型泡沫混凝土回填后隧道明洞衬砌结构进行受力和安全性计算,并与C15普通混凝土回填的计算结果进行对比。结果表明,采用CF0.5泡沫混凝土回填时,仰拱底安全系数为0.92,其余置换回填方法的仰拱底和拱脚的安全系数均大于1.0;综合考虑隧道处于强震区,确定CF5.0泡沫混凝土为回填材料,回填后拱脚安全系数为8.9,仰拱底安全系数为3.4。

In order to solve the problem of heavy load in the construction of rerouted roads on the upper part of the backfilled open cut tunnel,taking the newly built Mawuliang Tunnel in Longnan section of Jingli Expressway as the research object,light foam concrete was used to replace the original design ordinary concrete materials,and the stress and safety of the open cut tunnel lining structure after backfilling with three different light foam concrete were calculated using the numerical simulation method,and compared with the calculation results of C15 ordinary concrete backfilling.The results show that the safety factor of inverted arch bottom is 0.92 when CF0.5 foam concrete is used for backfilling,and the safety factors of inverted arch bottom and arch foot of other replacement backfilling methods are greater than 1.0.Considering that the tunnel is in a strong earthquake zone,CF5.0 foam concrete is determined as backfill material,and the safety factor of arch foot after backfilling is 8.9,and the safety factor of inverted arch bottom is 3.4.