Experimental research on high-water-content soil tunnel without systematic bolts

During the construction of systematic bolts in high-water-content soil tunnels, there are disadvantages, such as difficult hole completion, poor grouting effect, low anti-drawing strength, poor supporting effect and low cost-effectiveness ratio. In order to overcome the above disadvantages during the tunnel construction, the elimination of systematic bolts in high-water-content soil tunnels is proposed, and a new support structure of the combination of steel arch, shotcrete, reinforcing mesh, locking anchor pipe and longitudinal link steel bar is employed. In order to study high-water-content soil tunnel without systematic bolts on site, two monitoring sections are set in Ⅵ class surrounding rock of Tianhengshan Expressway tunnel of Harbin orbital expressway. The results show that the stress and deformation of the supporting structure are within the allowable range under the condition of elimination of systematic bolts replaced with locking anchor pipe, and that the primary support is safe. It can reduce the construction period and expenditure in high-water-content soil tunnel without systematic bolts and has significant economic value and social benefit.