Use of new technology in repair and renovation of Haji Abad tunnel

摘要

Haji-Abad tunnel, with the length of 250 m, is one of the most predominant parts of Bandar Abbas-Mashhad railway in Iran. This railway, with the length of 1000 km, connects Persian Gulf to middle Asia. Landslide and mountain pressure have been recognized as main causes of the deterioration observed in this tunnel. Thus, retrofitting and repairing of this tunnel seemed inevitable for continuing its serviceability. This paper deals with use of Fiber Reinforced Polymer (FRP) Technology and nail anchorage method in the tunnel walls and injection of Epoxy in the cracks for repair purposes. Control of transverse deformations, after upgrading of the tunnel, is also investigated in this paper. The factors, influenced on a systematic repair and reinforcement method, are varied and depended on identifying problems. In this work, after injection in tunnel walls at the entrance section, nailing operation was carried out. The structural cracks on the two side of the surface of tunnel walls were injected and repaired using by epoxy resin. In order to compensate the reduced shear and flexural strength of the reinforced concrete lining, after analyzing the tunnel structure, the surface of tunnel were strengthened by using carbon plate (CFRP) like a chessboard with dimension of 50 x 50 cm. At the end of the repair and reinforcement of the tunnel walls, for controlling and monitoring of the process by attaching a displacement meter on the wall, any displacement were recorded over time.