中文摘要：

超固结比OCR是评价软黏土变形和强度特性的重要参数。基于天津、上海、连云港、深圳、中山和珠海这6个沿海地区软黏土的原位十字板强度,系统地分析这些地区软黏土的固结状态,并探讨其形成机制。研究结果表明：（1）基于原位十字板强度得到的OCR要明显大于室内一维压缩试验的结果,室内压缩试验会显著低估沿海软黏土的OCR;（2）6个地区的OCR随深度的变化规律较为一致,OCR随深度增加,逐渐减小至某一稳定值,浅层均表现出一定的超固结现象,而深层的固结状态则表现出一定的复杂性;（3）现有模型能够解释我国沿海软黏土超固结的成因以及变化规律,浅部的超固结现象源于以风化胶结为主的＂表层作用＂,而深部的超固结则源于次压缩。考虑到软黏土突出的取土扰动问题,这种基于原位十字板强度的软黏土OCR评价及成因分析方法值得在我国沿海地区推广。

英文摘要：

The over consolidation ratio（OCR） is an important parameter to evaluate deformation and strength characteristics of soil. The consolidation states and formation mechanism of the soft clay were analyzed based on the field vane strength of soft clay at six coastal areas in Tianjin,Shanghai,Lianyungang,Shenzhen,Zhongshan and Zhuhai. It was found that the OCR obtained from the field vane tests（FVT） was much larger than that obtained from the one-dimensional compression tests in laboratory and that the laboratory tests significantly underestimated the OCR of these soft clays. The variations of OCR with depth for these six areas are very similar and the OCRdecreases to a stable value at a certain depth. The shallow soil shows over consolidation,but the deep soil shows some complexity. It was also found that Hanzawa and Tanaka？s model can explain the formation mechanism of over consolidation and the variation of OCR with depth. The over consolidation of shallow soils originates mainly from the complex＂surface effect＂ of cement or weathering,while the over consolidation of deep soil is due to the secondary compression. Considering the considerable sampling disturbance,this method based on FVT for evaluating OCR is worthy of recommendation for Chinese coastal areas.