| With the development of the economic recently, the highways, airfields and high earth filled dams have been constructed on a high speed. More and more constructions were failed because of the tensile cracks. So, to research whether there can be produce tensile cracks, study the reason of the cracks and decide how to treat the cracks, the acknowledgement about the propriety of the tension become more and more important. In this paper, five test methods are introduced. They are uniaxial and triaxial tension test, split, double punch and clay beam。By these methods, the tensile propriety of the cohesive clay was studied on two kinds of cohesive clays. By the study, the following conclusions were concluded: (1) The dry density and water content are the two important factors that affect the shape of the stress-strain curves of the cohesive clays. With increasing the dry density, the tensile strength increasing; And With increasing the water content, the tensile strength increasing first and then declining. (2) By the triaxial tension test, there are three different failure forms of the samples under different consolidation pressure. Only when the sample was failed because of the shear stress, the failure stress complies with the guideline of Mohr-Coulomb. (3) The tensile strength by the three indirect test methods is different with the direct test method. And for the indirect test methods, there are some factors that impact the result. Such as the diameter of the rigid gasket and the height of sample are the two important factors for the double punch method. For this study, the result of the split and double punch are lower than that of the direct method; and that of the clay beam is higher than that of the direct method. (4) By the limit element analysis of the double punch sample, the stress, strain, and deformation were studied. The result is consistent with the tests. The result of the limit element analysis validates the analysis of the mechanics about the double punch. |
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