Strength and failure characteristics of sandstone containing two circular holes filled with two types of inclusions under uniaxial compression

Abstract

Plate shaped sandstones containing two fabricated circular holes that were filled with gypsum and high-strength concrete respectively were prepared for studying the effects of ligament length L ligament incline angle α, as well as filling modes on their strength properties and failure modes. The results show that the initial cracks can be categorized as wing crack, axial tensile crack and curved tensile crack. The failure modes of ligaments can be categorized as mode of single inclined crack, mode of single axial crack and mode of two parallel cracks. The final failure modes of all specimens can be categorized as the tension-shear mixed failure and shear failure. The strength of inclusions shows little influence on the final failure modes of specimens, while the failure modes vary with L and α. When α is a fixed value, the peak strength σ_c and elastic modulus E_c of tested specimens increase firstly with increasing L and reaches to the maximum value at L of 16 mm, then declines. When L is a fixed value, σ_c declines firstly and then turns to increase as α increases to 75° from 45°, while E_c increases linearly. The axial stress σ_p performs the similar variation trends with those of σ_c versus increasing L and α when ligaments fail.

Keywords

sandstone / two circular holes / inclusions / uniaxial compression / failure modes / strength properties

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