DOI: 10.18503/1995-2732-2020-18-2-62-70
Abstract
Problem Statement (Relevance): The paper describes the features and results of determining the strength characteristics (angle of internal friction and specific cohesion) of uniformly graded bulk coarse-grained media used to construct open pit truck haul roads. Objectives: To determine the effect of a particle size on the angle of internal friction and the specific cohesion of uniformly graded bulk coarse-grained media. Methods Applied: Laboratory methods were applied to determine the strength characteristics using a direct shear apparatus and an improved oblique shear apparatus that implements the oblique cutting method. Originality: The novelty elements include a method for determining the strength characteristics of coarse-grained media using the improved oblique shear apparatus, which made it possible to establish the presence and dependence of specific cohesion on the particle size. Findings: It was revealed that there are no fundamental differences in mechanical performance obtained both with the direct shear device and the oblique shear apparatus, and, therefore, the latter can be used to determine the strength characteristics of bulk coarse-grained media. It was found that a twofold increase in the particle size of uniformly graded granular medium leads not only to an increase in the angle of internal friction by approximately two degrees, but also in specific cohesion up to 8 kPa. However, the increase in specific cohesion with a particle size of 3 mm or less proceeds according to a different law than with a grain size of over 3 mm. Practical Relevance: The data obtained will contribute to apply a more justified approach to the design of pavements with layers of uniformly graded bulk coarse-grained media by an additional assessment of their shear resistance, and serve as a basis for the development of a mathematical model for predicting the strength characteristics of polyfractional bulk materials.
Keywords
Open pit truck haul roads, angle of internal friction, specific cohesion, bulk media, crushed rock, strength.
For citation
Shabaev S.N. Influence of the Size of Uniformly Graded Bulk Media Particles on Strength Characteristics. Vestnik Magnitogorskogo Gosudarstvennogo Tekhnicheskogo Universiteta im. G.I. Nosova [Vestnik of Nosov Magnitogorsk State Technical University]. 2020, vol. 18, no. 2, pp. 62–70. https://doi.org/10.18503/1995-2732-2020-18-2-62-70
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