THE DEGREE OF LIQUEFACTION OF SEABED INDUCED BY STORM WAVE IN CHENGDAO SEA AREA

The types and locations of geological disasters in Chengdao sea area were collected and summarized by analyzing the geotechnical surveying information in this area. It revealed that some geological disasters such as pits, gullies, slump, mud flow, diapiric structures, rough seabed and buried ancient river channels, were distributed in the northwest, middle and southeast of the sea area, and the formation mechanism was simply introduced. Then the cyclic stress ratio (CSR) induced by wave in the seabed and cyclic resistance ratio (CRR) which is related with SPT-N and clay content were calculated, and safety factors of liquefaction contour map in the depth of 1 m was drawn under different degrees of wind wave. Some conclusions were got. (1) With increased level of wind wave, the whole region liquefaction of the sea area was gradually expanding. (2) Three good anti-liquefaction areas are mainly distributed in the middle of the oilfield. (3) In the southeast, the influence of soil liquefaction on oil wells and pipeline safety should be paid much attention during high wind waves, as the bad anti-liquefaction seabed exists here.