The highway runs through the tunnel through Than Vu mountain. According to the design, there are two tunnels, of which the left tunnel is 1,09 km long, the right tunnel is 1,13 km long, the north is in Dien Phu commune, Dien Chau district, the south is in Nghi Dong commune, Nghi Loc district. The width of each tunnel is 13,8 m, the distance between the two tunnel centers is 45 m.
The tunnel on the right will serve phase one of the project, the tunnel on the left is for the expressway extension in phase two.
Mr. Vo Son Hai, Construction Commander of Than Vu Tunnel, Hoa Hiep Co., Ltd., said that specialized agencies assessed the tunnel as having the most complex terrain and geology among the mountain tunnels on the North-South Expressway. Therefore, the construction process encountered many difficulties.
