Research on Laboratory Mixing Trial of Marine Deposit and Cement in Hongkong

Abstract

For improving soft foundation of marine deposit in a seawall project in Hongkong, ground improvement of Deep Cement Mixing (“wet method”) was firstly researched and applied for the first time. A series of testing including physical & mechanical characteristics and chemical components for marine deposit, and researches on laboratory mixing trial of marine deposit and cement was carried out. By analyzing testing results from laboratory trial, several main factors of soil properties (e.g. natural moisture content, sand fraction, organic content of soil) and cement content, curing age influencing the strength of cement-soil mixture were researched. The correlation of cement-soil mixture strength and different curing age are emphatically analyzed. And it’s found that strength of cement-soil mixture increased with the increase of cement content, and the strength increase with curing age is more dominant for the stabilized soil with a larger amount of cement (max. content 280 kg/m3). Testing results demonstrated that strength of cement-soil from 3 kinds of cement content in lab mix meet design requirements. Based on above research results, the feasibility of using DCM to improve the marine deposit in Hongkong is preliminarily verified, and important technical parameters (e.g. economical cement content) were suggested to be applied in following field DCM field trial.