Consolidation Properties of Dredger Fill over Liquid Limit under Different Back Pressure Levels

Abstract

Primary and secondary consolidation concur in the primary consolidation stage. Especially for the dredger fill with high moisture content, the coupling effect of primary and secondary consolidation was very obvious. Analysis on the secondary consolidation properties during primary consolidation is great significant to reveal the consolidation mechanism and identify the settlement calculation method. Therefore one dimensional consolidation tests were conducted with the dredger fill clay of Wenzhou over liquid limit. The tests were focused on the influence of different vertical loading and back pressure condition on soil’s secondary consolidation properties. The research showed that the secondary consolidation of dredger fill of in high moisture content was very obvious under the primary consolidation stage. The final consolidation pressure level was higher, the vertical deformation was larger at the same effective stress level. Through the consolidation tests with different back pressure levels, it further verified high pore pressure potential promoted the development of secondary consolidation. Further more, when the final consolidation pressure was a constant value, the total settlement of primary and secondary consolidation basically unchanged. So high pore pressure promoted the occurrence of secondary consolidation, but reduced and sped up the development of primary consolidation.