Abstract
The deformation and failure of rock materials are closely related to the strain energy characteristics during the loading process. These strain energy characteristics and rock properties are greatly affected when the rock is subjected to the acidic solution. To study the effects of chemical solutions with different pH on the mechanical properties and strain energy mechanism of mudstone, the chemical corrosion mudstone samples are subjected to a uniaxial loading testing machine (CN64 electro-hydraulic servo). The corrosive effects of the acidic solution on the porosity, strain energy characteristics, and failure mode of mudstone samples were thoroughly investigated. The findings of this research indicate that: (1) The rate of change in the porosity and chemical damage coefficient of rock samples after chemical corrosion decreases, which is closely linear with the increase of solution pH; (2) The total strain energy, elastic strain energy, and dissipative strain energy decrease with the increase of pH, and, as a result, it is proposed that the observed turning point of the proportion curve of dissipated strain energy from decline to rise is used as a precursor point of the rock failure; (3) The stress value of the failure precursor point increases and the strain value decreases with the increase in pH value. However, the ratio of the stress value of the failure precursor point to the peak stress hardly changes with pH value, and its value is about 0.883; and (4) Rock samples soaked in a weak acidic chemical solution (pH 7.3 and 5.3) are damaged by tensile crack, while rock samples soaked in a strong acidic chemical solution (pH 3.3 and 1.3) are mainly damaged by the combination of tensile and shear. The findings of this study can be used to provide an experimental and theoretical foundation for monitoring rock engineering disasters such as slope, tunnel, and coal mine failures.
Highlights
This article is an open access articleThe strain energy characteristics during the loading process are intimately related to the deformation and failure of rock materials
In view of the above, this research study discusses the law of water-rock interaction, analyzes the failure process of mudstone samples after chemical corrosion under uniaxial loading from the perspective of strain energy, and puts forward a new method to determine the precursors of rock failure
The total strain energy, elastic strain energy, and dissipative strain energy at the peak stress point decrease with the increase in the pH value of a chemical solution
Summary
The strain energy characteristics during the loading process are intimately related to the deformation and failure of rock materials. It is essential to examine the effect of hydrochemical solutions on rocks’ mechanical properties and strain energy characteristics from both a theoretical and an engineering perspective. Ionic composition and pH value have a great influence on the mechanical properties of sandstone, and the peak strength, residual strength, and elastic modulus of the rock after corrosion by various chemical solutions decreases to different degrees. Han et al [20,26] studied the damage degradation mechanism and mechanical properties of sandstone specimens under the coupling effect of different chemical solutions and rapid freeze-thaw cycles. In view of the above, this research study discusses the law of water-rock interaction, analyzes the failure process of mudstone samples after chemical corrosion under uniaxial loading from the perspective of strain energy, and puts forward a new method to determine the precursors of rock failure. The findings of this study can be used to provide an experimental and theoretical foundation for monitoring rock engineering disasters such as slope, tunnel, and coal mine failures
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