关键词: 珊瑚砂, 饱和方式, 峰值偏应力, 颗粒破碎

Abstract: Due to its special deposition environments, the coral sand has the characteristics of high voids with inner porous, low individual grain strength and prone to grain breakage. The high porosity of coral sand sample is difficult to reach high degrees of saturation in the sample preparations for the laboratory tests. This paper presents the triaxial test results on samples under different degree of saturations. The test results indicate that, the tested peak strength and the internal friction angle reach the maximum on sample saturation prepared by vacuum method followed by the submerging saturation method, and the back pressure saturated samples have the minimum peak strength and internal friction angle. With the increasing of confining pressure, the internal friction angle differences on samples prepared by different saturation methods are smaller. The grain breakage during the sample preparation by different methods has obvious difference with submerging method having the maximum amount of grain breakage and vacuum method having minimum amount of grain breakage. It is also concluded that the grain breakage is an important factor that affecting the peak oblique stress value. Since part of the grain breakage occur during the sample preparation, the amount of total grain breakage cannot completely be associated with the peak oblique stress value. It is necessary to conduct microscopic study on the samples and comparing the differences induced by different saturation methods so that the impact of the sample saturation methods on the shear strength properties of the coral sand samples can be evaluated.