渤海海峡跨海通道地质条件调查与分析

 渤海海峡跨海通道建设是一项重大战略性涉海工程，对工程区域进行系统的地质地球物理调查与分析是工程前期的基础工作。在收集已有资料和实际勘测基础上，分析了渤海海峡海底地貌特征，初步查明了新近纪以来的地层岩性结构，甄别出了主要的活动断裂，开展了渤海海峡及邻区地震活动性分析，并对潜在震源区进行了划分。结果表明：侵蚀陡坎、沟槽、侵蚀洼地、潮流沙脊及水下浅滩等是通道建设的不利因素；沿长岛列岛岛链基岩埋深较浅，有利于海底隧道施工；拟建跨海通道位于震级上限6.0～7.0潜在震源区，其中，7.0级潜在震源区主体位于张家口-蓬莱断裂带，是工程抗震的重点设防区。

Survey and analysis of the geological conditions in trans-sea channel of Bohai strait

Because the construction of trans-sea channel of Bohai strait is a strategic marine engineering project, a systematic geological and geophysical investigation as well as analysis in the area is foundamental in the early stage of engineering. In this paper, on the basis of existing information and actual survey, seabed topographical features of the Bohai strait are analyzed, the strata lithologic structure since the Neogene is preliminarily investigated, major active faults are identified, a seismicity analysis on Bohai strait and its neighboring area is carried out, and areas of potential seismic source are divided. The results show that erosion scarp, erosion groove and depression, tidal sand ridge, and underwater shoal are the unfavorable factors of the channel construction. The area along the Changdao islands chain is conducive to the undersea tunnel construction for the bedrock buried depth is shallow. The proposed cross-sea channel is located in the potential seismic source area with a maximum magnitude of 6.0~7.0; the main part of the potential seismic source area with 7.0-magnitude is located within Zhangjiakou-Penglai fault zone, where the key seismic fortification for the engineering is.