Influence of Pore Water Salinity Effect on Identification of Soft Clay Based on CPTu in Lianyungang
In-situ tests classify soils by their macro mechanical behaviors, while many laboratory investigations suggested that the chemical composition of pore water has significant influence on both physical and mechanical properties of clay. In this paper, Cone penetration test (CPTu) was conducted in Lianyungang (LYG) marine-deposit plain in order to investigate the influence of pore water salinity effect on in-situ test. Hereafter, the influence on the classification parameters of the Soil Behavior Type chart and the Eslami-Fellenius chart were discussed respectively. The results suggested that the Eslami-Fellenius chart was more suitable to identify LYG marine soft clay. Theoretical solutions of cavity expansion in modified Cam clay were proposed to interpret CPTu. It was inferred that pore water salinity effect could influence the classification parameters and lead to the deviations of projections in classification chart. Despite the parameters used in Eslami-Fellenius chart were also affected, soft clay was generally identified for the low sensitivity of their parameters to the change of pore water salinity. As a conclusion, pore water salinity effect should be taken into consideration while interpreting CPTu data with respect to marine clay.
KeywordsCPTu Marine clay Soil classification Salinity effect
This study is supported by the National Natural Science Foundation of China (Grant No. 51378117, 41572280), China Scholarship Council and Fundamental Research Funds for the Central Universities (Grant No. KYLX_0148), and Guangxi and Nanning Science and Technology Project Grant (No.14124004-4-12, 20143113).
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