This work presents a study on the behaviors of diatomaceous soils. Although studies are rarely reported on these soils, they have been identified in Mexico City, the Sea of Japan, the northeast coast of Australia,the ...This work presents a study on the behaviors of diatomaceous soils. Although studies are rarely reported on these soils, they have been identified in Mexico City, the Sea of Japan, the northeast coast of Australia,the equatorial Pacific, and the lacustrine deposit of Bogota(Colombia), among other locations. Features of this kind of soil include high friction angle, high initial void ratio, high compressibility index, high liquid limit, and low density. Some of these features are counterintuitive from a classical soil mechanics viewpoint. To understand the geotechnical properties of the diatomaceous soil, a comprehensive experimental plan consisting of more than 2400 tests was performed, including physical tests such as grain size distribution, Atterberg limits, density of solid particles, and organic matter content; and mechanical tests such as oedometric compression tests, unconfined compression tests, and triaxial tests.Laboratory tests were complemented with scanning electron microscope(SEM) observations to evaluate the microstructure of the soil. The test results show that there is an increase in liquid limit with increasing diatomaceous content, and the friction angle also increases with increasing diatomaceous content. In addition, several practical correlations were proposed for this soil type for shear strength mobilization and intrinsic compression line. Finally, useful correlations were presented, such as the relationship between the state consistency and the undrained shear strength, the friction angle and the liquid limit, the void ratio at 100 kPa and the liquid limit, the plasticity index and the diatomaceous content, among others.展开更多
This paper presents the mechanical behaviors of the lacustrine deposit,a representative soil in Bogota,Colombia.Initially,the physical characterization of the deposit is performed via laboratory tests (grain size dist...This paper presents the mechanical behaviors of the lacustrine deposit,a representative soil in Bogota,Colombia.Initially,the physical characterization of the deposit is performed via laboratory tests (grain size distribution,scanning electron microscopy,Atterberg limits and water content).This characterization intends to explain the special characteristics of the mechanical behaviors of this soil.Then,various triaxial tests are carried out with controlled loading path,strain rate change,relaxation,extensile stress,and cyclic loading.The test results reveal the shape of the yield curve for Bogotá soil (in a natural state),and also show that an increasing effect of the strain rate depends on the liquid limit.This effect is also preserved with extensile stresses (which are poorly studied in soil mechanics).Finally,other effects,such as the loss of structure in the reconstituted samples and the effect of shear modulus at low strains,are studied for Bogota soil.展开更多
文摘This work presents a study on the behaviors of diatomaceous soils. Although studies are rarely reported on these soils, they have been identified in Mexico City, the Sea of Japan, the northeast coast of Australia,the equatorial Pacific, and the lacustrine deposit of Bogota(Colombia), among other locations. Features of this kind of soil include high friction angle, high initial void ratio, high compressibility index, high liquid limit, and low density. Some of these features are counterintuitive from a classical soil mechanics viewpoint. To understand the geotechnical properties of the diatomaceous soil, a comprehensive experimental plan consisting of more than 2400 tests was performed, including physical tests such as grain size distribution, Atterberg limits, density of solid particles, and organic matter content; and mechanical tests such as oedometric compression tests, unconfined compression tests, and triaxial tests.Laboratory tests were complemented with scanning electron microscope(SEM) observations to evaluate the microstructure of the soil. The test results show that there is an increase in liquid limit with increasing diatomaceous content, and the friction angle also increases with increasing diatomaceous content. In addition, several practical correlations were proposed for this soil type for shear strength mobilization and intrinsic compression line. Finally, useful correlations were presented, such as the relationship between the state consistency and the undrained shear strength, the friction angle and the liquid limit, the void ratio at 100 kPa and the liquid limit, the plasticity index and the diatomaceous content, among others.
基金Universidad Nacional de Colombia and Los Andes University in Colombia for their technical and financial support
文摘This paper presents the mechanical behaviors of the lacustrine deposit,a representative soil in Bogota,Colombia.Initially,the physical characterization of the deposit is performed via laboratory tests (grain size distribution,scanning electron microscopy,Atterberg limits and water content).This characterization intends to explain the special characteristics of the mechanical behaviors of this soil.Then,various triaxial tests are carried out with controlled loading path,strain rate change,relaxation,extensile stress,and cyclic loading.The test results reveal the shape of the yield curve for Bogotá soil (in a natural state),and also show that an increasing effect of the strain rate depends on the liquid limit.This effect is also preserved with extensile stresses (which are poorly studied in soil mechanics).Finally,other effects,such as the loss of structure in the reconstituted samples and the effect of shear modulus at low strains,are studied for Bogota soil.
