关键词: 抗拉强度, 试验方法, 单轴拉伸, 三轴拉伸, 土梁弯曲, 轴向压裂试验, 径向压裂试验, 巴西劈裂

Abstract: Tensile strength, like compressive strength and shearing strength, is one of the most important engineering indexes to describe the properties of soil. Tensile strength is also the base of studying the characteristics of soil tensile damage; but tensile strength is always neglected in geotechnical engineering practice because it is relatively small on the value and hard to measure. With tension failure of the project more and more problems, the tensile strength properties of the soil caused by the concern of many scholars, research results are more and more. The paper on soil tensile strength test conducted systematic research methods and summarized, comparative analysis of the advantages and disadvantages of every method; it is recognized (1) The methods used in tensile strength tests can be cataloged into two classes of direct tensile test and indirect tensile test generally; in direct tensile test, tension force is directly applied on both ends of the specimen until the fracture occurs; then, tensile strength can be calculated with the maximum tension and fracture surface area; indirect method is mainly through a number of theoretical assumptions, the compressive stress is converted into the corresponding tensile stress and tensile strength of soil calculated based on some theoretical formula. (2) According to different stress conditions, the direct tensile test can be divided into uniaxial tensile test and triaxial tensile test. Generally speaking, both these two methods need special test apparatus to apply tensile load and realize its effective transfer within the specimen. Different designs are used in the apparatuses, such as glue, anchoring, mould and friction. Every design has its advantages and disadvantages; but mould is convenient for use comparatively; indirect tensile test mainly includes the split tensile test (Brazilian test), soil beam bending test and the axial fracturing test. These methods are adapted to stiff soil better, like chemical reinforced soil. Finally, some important research topics that should be well investigated in the future are proposed, including the establishment of standard tensile strength testing methods, developing simple soil tensile test apparatus, finding the method to measure and control the suction, acquiring the strain field information and numerical simulation research during the test.

Key words: tensile strength, test methods, uniaxial tensile, triaxial tensile, soil beam bending, axial fracturing test, Brazilian splitting test