Abstract:

The Hsuehshan Tunnel, passing through the northern end of Hsuehshan Range, situates in the northeastern region of Taiwan. This 12.9 km tunnel consists of 2 main tunnels, 1 pilot tunnel and 3 sets of ventilation shafts along the tunnel profile. In the beginning of the construction, tunnel boring machines (TBMs) didn't work well due to the heterogeneous geological conditions, causing the progress of the project lagging behind schedule. To shorten the construction period, the Engineers decided to create additional working faces for the horizontal tunnels through the 250 mdepth ventilation shaft No.2. With the help of the open through of connection tunnels and detour adit, 10 working faces with total length of 5,600 m through the shaft added to the horizontal tunnel excavation, the project progresses had been greatly improved. The construction layouts, mucking operation, ventilation system, drainage arrangement and emergency measurements of working faces through the shaft are so different from the ordinary tunnel excavation. They are introduced in this paper and will be beneficial to the future project of similar characteristics.

Key words:  shaft  horizontal tunnel  working face  connection ,  detour adit