Comparative Analysis Of Tensile Strength Test Methods

Tensile strength is the maximum ability of a material to resist tensile damage and is of great significance in engineering practice.The gestation and development process of geological disasters such as collapse,landslide and ground fissure are closely related to the tensile properties of rock and soil.Tensile strength testing methods are divided into two categories: direct stretching and indirect stretching.Direct stretching includes uniaxial stretching and triaxial stretching,and indirect stretching includes radial fracturing(Brazil splitting),axial fracturing(double-sided stamping),and soil beam bending.Previous studies have focused on uniaxial stretching,Brazilian splitting and axial fracturing.The tensile strength measured by different test methods is quite different.In this paper,the Malan loess in Yuci area of Shanxi and the gypsum samples made of gypsum and standard sand are used as research objects,using new radial fracturing method,new annular stretching method,uniaxial stretching method,Brazilian splitting method and The tensile test of tensile strength was carried out by the method of soil beam bending.The advantages and disadvantages of the five methods were analyzed and evaluated.The main research results are as follows:(1)For the undisturbed sample,the stability of the radial fracturing test results is the best;for the remolded samples,the stability of the Brazilian split test results is optimal;for gypsum samples,the soil beam bending test results are the most stable.(2)The tensile strength test value is significantly affected by the test method.The tensile strength test values of the same sample are the bending strength,uniaxial tensile strength,Brazilian splitting strength,radial fracturing strength and annular tensile strength of the soil beam from high to low.(3)The samples required for the radial fracturing method and the Brazilian cleaving method are easily prepared cylindrical samples.The direct tensile method and the annular tensile test sample are further processed on the basis of the cylindrical sample.The sample required for the soil beam bending method is a rectangular parallelepiped sample.(4)Uniaxial stretching method,Brazilian splitting method and soil beam bending method test load is generally provided by the universal testing machine,and require additional parts;the test process is complicated and cumbersome,low in efficiency and greatly affected by human influence.The radial fracturing method and the annular drawing test device are light and simple,easy to handle,and have no additional components,simplifying the test operation and improving the test efficiency.(5)Based on different test methods,the tensile strength,maximum displacement and tensile modulus of undisturbed loess are larger than that of remolded loess,and the dispersion of test results is significantly higher than that of remolded loess.