Research On The Application Of Cone Penetration Test In Offshore Geotechnical Engineering

Cone Penetration Test (CPT) is a quick, continuous data, repeatable andpenetration details, and rapid operation in-situ testing method. Following the rapiddevelopment of offshore engineering, offshore CPT has been developed as aninternationally recognized standard, and become more and more widely used insupporting the development of offshore industry. Therefore, it is important to knowthe marine CPT equipments and the application of CPT technology, to discuss theproblems during interpretation and analysis using CPT data, to verify the suitabilityof the interpretation of CPT data, to propose the reasonable empirical factors used toobtain soil parameters in offshore geotechnical engineering in China.The purpose of this paper is to verify and improve the approaches to interpretsoil parameters using CPT data. For this purpose, the CPT data,boring data andlaboratory soil testing results were collected from sites in offshore geotechnicalinvestigation in our country. This paper contains discussion on the interpretationapproaches using CPT data based on theories analysis and comparison between theinterpretation results from CPT and laboratory soil testing results, and suitableempirical factors for studied sites are proposed.The adopted soil classification charts using CPT data were used to identify thesoils at various depths, and the interpretation results from CPT data and laboratorysoil testing results were compared and analyzed. Some soil behavior typeclassification charts were discussed, and a reasonable CPT classification chart isrecommended in this paper.This paper presents the interpretation for estimation of undrained shearstrength in cohesive soils, over-consolidation ratio in cohesive soils, sensitivity incohesive soils and relative density in granular soils using the adopted approaches.The correlations between the estimation results based on CPT data and laboratorytesting results were discussed, and the empirical factors for the study sites areproposed.The approaches of direct application of CPT/CPTU results to estimate the pilecapacity and evaluate the potential for granular soil liquefaction were introduced,and the problems during interpretation of CPT data were discussed.