| Reclamation project increases a lot recent years because of the increasing demand on urban land. Dense sand is often used in reclamation project. Studies on dense sand are still not systematic, In terms of the triaxial test, most of them focus on high confining pressure, or separately drained and undrained test, or separately extension and compression tests. The seismic response analyses mainly focused on loose sand site and the seismic response analyses on dense sand site were limited. Therefore, the study on the dense sand is necessary.This thesis is one part of the studies on the seismic response on sand site in Shenzhen. The main contents, method and conclusions are presented as the follows: First, tension, compression, and cyclic loading tests were conducted on Pingtan sand with a relative density of 80% using the GDS triaxial apparatus. The purposes of the tests were to study the mechanical properties of dense sand, to calibrate parameters in the constitutive model. The cyclic loading test results showed that dense sand had a stronger resistance to liquefaction compared with the loose sand. It was also found that the cyclic stress ratio, the consolidation stress ratio, the initial effective confining pressure have a great effect on liquefaction, strength and deformation of dense sand.Second, a critical sand model with state dependent dilatancy was selected and software SUMDES2006 was used to conduct preliminary analyses on seismic response on dense sand site. According to the development of the settlement, horizontal displacement, acceleration and pore pressure after seismic waves with different peak acceleration passing dense sand site, the effects of shaking intensity on the dense sand site were analyzed. The results showed that the seismic wave was still amplified but not significantly in the dense sand site closing to the liquefaction. The dilatancy often occoured before liquefaction and had great influence on vertical settlement and lateral displacement.
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