Experimental Study on Influence of Chemical Corrosion on Mechanical Property of Fissured Granite

Fan Zhang,Junjiekang Junjiekang,Tao He,Dawei Hu

doi:10.1155/2021/6649824

Fan Zhang, Junjiekang Junjiekang + Show 2 more

Open Access

https://doi.org/10.1155/2021/6649824

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Abstract

The effect of chemical corrosion and natural joints on the damage characteristics and strength of rock masses is highly important for the construction of rock engineering and energy extraction. Therefore, the intact granite is processed into prefabricated fissured granite specimens with a fissure angle of 0°, 30°, and 45°. Chemical corrosion tests are then performed on the prefabricated fissured granites. The pH of the solution gradually becomes neutral; the mass loss of the granite specimens and the mineral compositions of the fissure surface are measured and analyzed. The scanning electron microscopy (SEM) and uniaxial compression tests are performed on the granite specimens after chemical corrosion. After chemical corrosion, the surface of the fissure becomes loose. The various mineral components of the specimens have been changed to different degrees or converted into other mineral components. The peak strength and elastic modulus of the prefabricated fissured granites with the three fissure angles present a clear decrease, as the time of chemical corrosion increases. The stress intensity factors at the fissured tip are also analyzed. The stress intensity factors of the specimens with a fissure angle of 0°, 30°, and 45° decrease from 0.017, 0.35, and 0.84 to 0.013, 0.30, and 0.74 MPa·m1/2, respectively, as the time of the chemical corrosion increases. And the chemical corrosion has the largest effect on the intensity factors of the specimens with a fissure angle of 45° among the three angles. These experimental results could improve the understanding of the long-term stability of underground engineering in the multifield coupling environment.

Highlights

Due to the function of crustal movement and weathering, a large number of fissures with different sizes are induced inside rocks
Because the active mineral content of the initial granite surface is relatively high, H+ ions are quickly consumed in the chemical solution; as the reaction progresses, the granite surface active minerals decrease, resulting in a decrease in the chemical dissolution rate
The stress intensity factors of the specimens with α = 0° are the smallest or even close to 0, while the specimens with α = 30° and α = 45° have a large quantity of stress concentration at the fissured tip, and the chemical corrosion has the largest effect on the intensity factors of the specimens with α = 45° among the three angles

Summary

Introduction

Due to the function of crustal movement and weathering, a large number of fissures with different sizes are induced inside rocks. A large number of experimental studies have focused on the physicomechanical properties of fissured granite, such as ultrasound characteristic strength, elastic modulus, and fracture behaviors [1,2,3,4]. In addition to the traditional analysis of mechanical parameters of fissured granites, some scholars confirm that the fracture criterion is related to the properties of the rock, prefabricated cracks, and types of loading [5]. In order to supplement previous research results, crack propagation [9, 10] and coalescence [11, 12] with prefabricated fissures have been extensively studied by experimental and simulation research.

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