The Shear Strength Increase Evaluation Of Soft Soil During Consolidation

The soft soil distributed in the coastal areas of our country has many unfavorable project properties such as high water content, huge compression index and small shear strength. Research shows that the shear strength increases with the dissipation of the pore pressure and increasing of the effective stress. It's favorable to reduce to the foundation treatment cost and ensure security of construction making full use of the increase of shear strength. Therefore, it is instructional significant to evaluate the increase of shear strength due to the consolidation of soft soil.Some common analytical methods for the increase of shear strength were compared first in this paper. All previous field vane tests and laboratory tests of Duhu construction and a power plant sea dike construction were collected and summarized. Finite element analysis was adopted to analyze the consolidation of three typical segments of sea dike engineering. And the variation procedure of effective stress and excess pore pressure were obtained. Consolidation pressure method and effective stress method were used to analyze the shear strength of the soil for different periods, respectively. And the results were comparison with the value measured by field vane tests to verify the validity of the method. The average degree of consolidation based on one dimension consolidation was used to analyze the foundation shear strength of Duhu Lake. And the calculated shear strengths were compared with these measured from field vane tests. Analysis results show that the consolidation pressure method with consolidated undrained strength parameters can reflect the shear strength reasonable, while the effective stress method with effective stress parameters should be revised to consider the effect of time in consolidation.