A Preliminary Analysis of the Tomography Problems in Constructing Bridge and Dike-Road across Taiwan Strait

The construction of the bridge across Taiwan Strait has been studied for a long time and the feasibility study that has attracted attention among scientists and engineers on both sides of the Taiwan Strait. The key question is whether this bridge and dike-road across Taiwan Strait can be constructed with present technology under such complex geological conditions or not. The results of current researches indicate that the sea floor of the Strait is covered with a horizontal layer composed of both the Pleistocene and the Holocene sandstone and shale with a thickness of about 200~300m. The distance from Pingtan island to Xinzhu seashore is 124 km,which might be connected by 4-6 section bridges and 5-7 section of dike-roads, and serve as a best program of the route in the north Strait section. The NE offshore fault along the Fujian coast and that along the west coast of Taiwan are the major tectonic lines separated by several NW faults under the upper horizontal layer, these fault's 3D feature may be detecting by geo-tomography technique, which can help to deal with the foundation of bridge and dike-road piers. It is judged that the construction of bridge and dike-road beginning from Pingtan to the Xinzhu seashore is worth recommendation. In the procedure of the construction of large and high height bridges, must consider the steel structural member be detected by industrial CT technology, and might detect the pier of bridge and dike-road which built by steel tube and reinforced concrete at dike-roads two side, in order to get the hard basement and getting the depth of the pier extend below the sea-floor by the seismic tomographic detection method.