Testing method of soil mass triaxial breaking stress path based on negative confining pressure condition

Abstract

The invention discloses a testing method of a soil mass triaxial breaking stress path based on a negative confining pressure condition. The testing method is based on a uniform section loading axis triaxial instrument. The testing method comprises the following specific steps: preparing a cylindrical sample; applying chemical glue on the side surface of the sample, and putting the sample into a rubber membrane; gluing the sample with a pressure chamber sample base and the end part of a loading axis through super glue after the rubber membrane is glued with the sample; finally performing two types of testing on the sample: performing soil mass triaxial tensile stress route testing in a negative confining pressure condition (NP-TTSP): ensuring that the sample is under isotropic equal tensile stress and the negative confining pressure is not changed, and gradually increasing the axial tensile stress till the sample is broken; performing soil mass triaxial compression stress route testing in a negative confining pressure condition (NP-TCSP): ensuring that the sample is under isotropic equal tensile stress and the negative confining pressure is not changed, and gradually applying axial tensile stress when the axial tensile stress is reduced to zero till the sample is broken. The testing method lays a foundation for the development of strength characteristic research on loess in a tension and shear stress route condition.

Description

technical field [0001] The invention belongs to the technical field of geotechnical engineering test methods, and relates to a test method based on the triaxial failure stress path of soil under the condition of negative confining pressure. Background technique [0002] Due to the low tensile capacity of soil, the influence of soil tensile strength on geotechnical structures is often neglected. However, the failure of many geotechnical structures is related to the tensile properties of soil. In recent years, with the rapid development of the economy and the vigorous construction of highways, airports, and high earth dam slopes, the problem of cracks in geotechnical structures has always existed, which shows that the impact of the tensile strength of soil on geotechnical structures cannot be ignored. Therefore, it is very important to have a correct understanding of the tensile properties of soil and an accurate measurement of the tensile strength index. [0003] Using a uni...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a test method based on the triaxial failure stress path of the soil under the negative confining pressure condition, and solve the technical method problem of the triaxial stress path realization method of the loess slope soil under the combined tension-shear stress condition

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