琼州海峡西线跨海通道工程地质评价

为开展琼州海峡跨海通道地壳稳定性评价，避免潜在的地质灾害对跨海通道工程安全性产生不利影响，利用侧扫声纳、单道地震、多波束等地球物理探测方法对琼州海峡海底展开了地形地貌调查，获得了琼州海峡跨海通道工程区海域活动断层分布、西线规划区地形地貌及地质条件等基础地质资料。工程地质评价认为西线线路断裂、地震、火山活动性弱，海底水深小、地形较为平坦、地貌简单，上新世望楼港组低液限粘土及上新世浅海相砂层作为基础持力层，岩土工程力学性质尚可，利于开展跨海通道桥梁方案施工。规划线路穿越1处侵蚀沟槽，影响长度约5 km，地形高差达60 m，且线路东临1处海釜，分布有陡坎，且部分地段分布有滑塌堆积。建议西线线路北段局部西移约1.5 km，同时关注西口潮流侵蚀沟槽、规划区南部淤泥质软土、古河道砂性土沉积、海峡谷底活动沙坡等不良地质作用影响。 

ENGINEERING GEOLOGICAL EVALUATION ON THE WEST LINE OF THE CROSS-SEA CHANNEL IN THE QIONGZHOU STRAIT

For the crustal stability assessment of the cross-sea channel engineering in the Qiongzhou Strait, geophysical survey methods including side-sweep sonar, single channel seism and multi-beam were applied to investigate the topography and geomorphology of the Qiongzhou Strait. The side sweep sonar images, topographic and the distribution of active faults were obtained. The engineering geological evaluation shows that the fault, earthquake, and volcanic activities in the planned area of the line are weak, the seabed water depth is shallow, the terrain is relatively flat, and the landform is simple. The low liquid limit clay of the formation and the Pliocene neritic facies sand layer could be used as the basic supporting layers, and the mechanical properties of geotechnical engineering are acceptable, which are conducive to the construction of bridges across the sea. Research demonstrates that the planned line passes through an erosion trench, affecting a length of about 5 kilometers, with a terrain height difference of 60 meters and a sea kettle to the east of the line, along with steep slopes as well as slump deposits in some parts of the area. It is proposed that the northern section of the line be partially moved about 1.5 kilometers westward. At the same time, attention will be paid to the erosion of trenches in the West mouth, muddy soft soil in the southern part of the planning area, sandy soil deposits in ancient rivers, and active sand waves at the bottom of the strait.