Research On The Mechanical And Failure Characteristics Of Rock-like Samples Subjected To Water Intrusion

Water-rock interaction has consistently been one of the research interests and difficulties in the rock mechanics field. As a common rock, sandstone is concerned with almost every respect of underground mining activities. Besides, the properties of underground rock are distorted to a certain extent by the special environment, for example, water intrusion. So far, the research has been done mainly focuses on the mechanical properties of a specific rock in dried, natural, and saturated conditions, with little attention been paid to the rock itself. In this paper, with the purpose of providing positive reference for underground design and construction, we investigated the mechanical properties and failure forms of water-intruded rock-like samples with different particle sizes.Using experiments and numerical calculation, this paper systematically studied the mechanical properties and failure forms of water-intruded rock-like samples with different particle sizes. The relationship between moisture contents and water intrusion time is revealed by the water absorption experiment, which mainly involves the rapid, slow, and level-off stages in terms of its rising speed. The uniaxial compressive experiment on rock-like samples demonstrates the effect of moisture contents and particle sizes on uniaxial compressive strength, elastic modulus, and peak strain, respectively. Specifically, the uniaxial compressive strength and elastic modulus is negatively related to moisture contents, while a direct proportion relationship is observed between peak strain and moisture contents. The effect of particle size on uniaxial compressive strength, elastic modulus, and peak strain conforms correspondingly to the inverse, direct, and negative proportional functions, followed by the sensitivity analysis. Acoustic emission test is performed on water-intruded rock-like samples with different particle sizes. From the perspective of AE count, AE characteristics in each loading stage are studied with the factors of moisture contents and particle sizes considered. Based on the stress-strain curves from experiments, numerical calculation software, PFC2 D, is adopted to calibrate parameters before simulating uniaxial compressive and AE tests. After simulation, how the moisture contents and particle sizes affect the internal fracture development and sample failure forms is concluded. Generally, samples with a higher moisture content has a lower total AE count, while more AE signals are recorded in samples with greater particle sizes.