Research On Engineering Geological Environment And The Suitability Of Pile Foundation In Western Laizhou Bay

The Laizhou Bay located in the northern part of Shandong Peninsula is one of the important shallow sea oil and gas regions. With the constraction of offshore platform, oil pipelines and artificial islands, it is need for a comprehensive understanding of the engineering geological environment of the Laizhou Bay.Through systemly collecting the material of the characters of climate, marine hydrology, regional geology and shallow stratigraphy, etc, this article analysis the engineering geological environment, which contents the regional crustal stability, the engineering geological characters of shallow stratigraphy and geologic hazard, and the suitability of pile foundation of the weastern Laizhou Bay.The results of this study are as follows:the stability of the study area's crust is substable according to the activities of the faults and earthquake and the lifting rate of crust, etc.Coastal area of western Laizhou Bay influenced by the sediment of the Yellow River, the upper part is the modern Yellow River deltatic sedimentation, which the top floor is silt, underlied with silt and silty clay interbedded strata. This part has bed engineering geological characters with high water content, high compressibility, low shear strength and soft plastic-flow plastic. At the middle of shallow stratigraphy the engineering geological characters of marine facies that silt and silty clay interbedded strata is better than upper's. The land facies at the bottom has the best engineering geological characters that the content of sand increased obviously. The silty soil in coastal area less prone to liquefaction according to liquefaction analysis.Less affected by the Yellow River, the upper part in deep sea is brown clay, reflecting the offshore sediments, which with high water content and low shear strength. The brown-gray land facies silty sand underlied the upper part has the fine engineering geological character that thick layer and high shear strength. At the bottom of the stratigraphy that silty sand or sandy silt interbedded have the vert high shear strength.Analysised by the AHP-Fuzzy Comprehensive Evluation Method engineering geological environment of the stuty area suitable for the construction and stability of the pile foundation of offshore platforms that influenced by sea ice, storm surges and weak interbed.