连云港浅层海相软土沉积环境及物理力学性质研究

SEDIMENT ENVIRONMENT OF SHALLOW MARINE CLAYS DEPOSITED IN LIANYUNGANG AREA AND THEIR PHYSICAL AND MECHANICAL PROPERTIES

海相沉积软土在连云港有3层分布,他们在各自不同年代沉积,而浅层的软土对高速公路工程中路堤的变形和稳定 性有很大影响,该土层在工程中备受关注。本文对连云港浅层软土的沉积环境,物理力学性质和结构性进行探讨和分析。收 集的资料表明连云港浅层的软土是在全新世黄骅海进到19世纪60年代期间沉积形成的,其沉积历时漫长。统计表明该浅层 软土含水量高、原位十字板剪切强度和有效上覆应力的比值约为0.2～0.4。最后根据Burland的理论分析了该层软土的结构 性,结果表明连云港表层的海相软土为高位结构软土,土样易受到扰动,导致室内强度的失真。

Three layers of shallow marine clays with different sedimentary history are observed in Lianyungang area. The upper layer of the soft marine clays is a major concern in engineering practice because of possible settlement and stability problems of embankment built over it. This paper assessed the sediment environment of soft marine clays and their physical and mechanical properties. The shallow marine clays were formed chronically in the Holocene between Huanghua (the Yellow Sea) transgression and 1860's A.D. The statistical results show that the clays have high water contents, and the ratio of their vane test strength vs. the effective overburden pressure ranges from 0.2 to 0.4. Burland's void index and intrinsic compression line are then used to characterize structures of the marine clays. It is concluded that highly structured clays can be easily disturbed, and the laboratory strength is distorted.