Because of the difficult morphological and geological conditions, many tunnel- and bridge-building projects in Taiwan present a considerable challenge to engineers and geologists. In the west of the island, marshland with saturated and only slightly consolidated loose stony deposits. The central area partly consists of highly metamorphic solid rock, is highly contoured and falls steeply towards the east coast. In addition, a very high degree of seismic activity and very high rainfall are present. The problems arising during the project and possible solutions are presented here.
Taiwan (Republic of China) is a country on the border of Eastern Asia where the population requires a high degree of mobility. The east coast of Taiwan in contrast can only be reached with difficulty because of the mountainous nature of the island (up to 4000 m high mountain range along the entire N-S axis). The traffic routes therefore must fulfill very stringent functional requirements. Despite the economic crisis in the east Asian region, the need to improve the infrastructure of the country remains. Countless railway, motorway and trunk road projects as well as underground railway projects in Taipei and Kaohsiung are at the planning or construction stage. DMT is currently involved in four large-scale projects, two of which are at the planning stage and two at the construction stage, and these will be described here with their special requirements, conditions and difficulties (see Figure 1).
The geology of Taiwan is decisively influenced by its position on an active continental shelf edge on which on the one hand the Luzon group of islands pushes against the Eurasian continental shelf and on the other hand the oceanic Philippine plate is subducted under the Ryukyu island group at the Ryukyu fault trough (Figure 2).