Poor ground conditions are delaying tunnelling on the southern section of the US$251m 6.3km Hai Van pass road tunnel in central Vietnam just months after Dong Ah Construction/Song Da Construction Corporation, the South Korean-Vietnamese Construction JV started work.
Project Management Unit 85 (PMU 85), the Vietnamese government client, confirmed that work is being dogged by the terrible conditions.
So far the JV has only tunnelled about 30m of the main drive since work started in July. Frequent tunnel collapses have severely hampered progress. PMU85 said site investigations had predicted there would be an area of weak ground stretching more than 100m but that the conditions have been worsened by heavy rains.
By comparison, work on a parallel second tunnel has progressed relatively smoothly and about 200m has been excavated, with the contractors averaging about 6m per day.
PMU85 has now told the contractors to focus on building the parallel tunnel until they have passed the area of weak ground when they will begin tunnelling on the main drive. Foreign experts are in the process of being called in to advise on remedial measures to complete the missing section.
Work on the northern section, by Japan’s Hazama Construction and Civil Engineering Construction Corporation No. 6 is unaffected and on course for early completion after work started last April. The contractors had driven about 200m on the main drive, 320m on the parallel auxiliary tunnel and 340m on a nearby ventilation tunnel. Construction of the tunnel is due for completion in 2003.
