Experimental Analysis of Clay Effect and Confining Pressure Effect on Mechanical Properties of Sea Sand

Triaxially consolidated drained shear tests by the GDS standard stress path were conducted on the Qinzhou Port sea sand under the different effective confining pressures and clay content, which was be analyzed the effect of effective confining pressure and clay content on the strength and deformation characteristics of sea sand in Qinzhou Port. The results showed:under the same effective confining pressure, as the clay content increased, the stress-strain curves of clay-contained sea sand converted from a strain-softening curve to a strain-hardening curve. The peak strength, relative stress softening coefficient, and volumetric strain decreased steadily; the peak strain increased simultaneously. In the same clay content, the peak strength of the specimens increased gradually with the increase of the effective confining pressure. When the effective confining pressure for specimens of pure sand was 300 kPa, the peak strength of specimens was 1.517 times higher than that whose confining pressure was 100 kPa. There was a good linear relation between the effective confining pressure and the peak strength. Simultaneously, the relative softening coefficient of stress and volumetric strain decreased with the increase of the effective confining pressure. Finally, in the range of 0% to 20% of the clay content, and the relation between the relative stress softening coefficient and the effective confining pressure and clay content was established.