Experimental Study on Mechanical and Acoustic Emission Characteristics of Rock-Like Material Under Non-uniformly Distributed Loads

Natural rock masses have many internal joints, fractures and faults, which greatly influence their mechanical properties during geological processes. In this paper, considering different joint angles and rock-bridge angles, uniaxial compression numerical tests on double-fractured red sandstone based on particle flow code (PFC) were carried out. The influence laws of the mechanics, acoustic emission (AE) and damage evolution characteristics of double-fractured sandstone under different crack geometry conditions were analysed. The results indicated that the peak stress and elastic modulus increase with increasing fracture angle. The peak stress and elastic modulus of rock samples first increase and then decrease with the increase in the rock-bridge angle, exhibiting a nonlinear distribution; when the angle β (rock-bridge angle) is less than or equal to 45 • , the peak strain differs only slightly and decreases gradually with the increase in the rock-bridge angle. There are three stages in the AE evolution of fractured red sandstone: The initial emission of AE, the increase in AE and the decline in AE. The influences of different fracture angles and rock-bridge angles on the AE characteristic rule of rock samples vary. The damage evolution process of sandstone specimens with different joints can be divided into four stages: Initial damage, stable increase, accelerated development and stable damage. The fracture angle mainly affects the damage stage. The smaller the angle of the crack is, the greater the strain value in this stage. The rock-bridge angle mainly influences the damage variable evolution during the stable increase, accelerated damage development and stable damage stages.

show abstract

“…Because it is difficult for the sandstone specimen to be completely damaged during compression, the damage variable can be corrected to [27,28]…”

Section: Rock Mass Damage Model Based On Ae Characteristicsmentioning

confidence: 99%

“…Equation (6) defines the damage variable based on the normalized cumulative AE ringing count, which is reasonable. Because it is difficult for the sandstone specimen to be completely damaged during compression, the damage variable can be corrected to [27,28]…”

Section: Rock Mass Damage Model Based On Ae Characteristicsmentioning

confidence: 99%

Numerical Study of the Mechanical and Acoustic Emissions Characteristics of Red Sandstone under Different Double Fracture Conditions

et al. 2019

View full text Add to dashboard Cite

show abstract

“…ere are a lot of parameters that can be used to define the damage variable (D), such as cracks [25], elastic coefficient [26], yield stress [27], elongation [28], AE [29,30], energy [31], etc. In this study, D is defined by the parameters of AE events as follows:…”

Section: Damage Model Based On Ae Eventsmentioning

confidence: 99%

Analysis of Mechanical and Acoustic Emission Characteristics of Rock Materials with Double‐Hole Defects Based on Particle Flow Code

Zhang

Wang

Tian

et al. 2018

Shock and Vibration

Self Cite

View full text Add to dashboard Cite

ere are a lot of fissures, holes, and other defects in the formation of natural rocks. Under the influence of the external loads, these defects may cause engineering problems. erefore, it is of great significance to analyze the characteristics of damage evolution of the defective rocks. In the study, the double-hole defective rocks with different angles of the center connection line are considered and the numerical models are established firstly. en the mechanical behavior and acoustic emission (AE) characteristics are analyzed systematically. Finally the laws of damage evolution of the defective rock materials are investigated based on the AE characteristics. e research results show that the stress-strain behavior of the defective rocks can be divided into elastic stage, plastic stage and failure stages. e characteristics of acoustic emission evolution and laws of damage evolution are closely related to the stress-strain relationship. e elastic modulus of the double-hole defective rocks is similar with different angles of the center connection line, but the peak strength is different. e shape of the peak strength of these defective rocks is a W type owing to the different failure modes. e influences of different angles of the center connection line on the characteristics of AE evolution include the maximum events number, the strain value of the initial AE events and the maximum AE events, and the strain range of the serious AE events. Different angles of the center connection line have different influences on the laws of damage evolution of the double-hole defective rocks.

show abstract

“…It has also been found that the mechanical properties of rock are significantly affected by the loading parameters. Of these, the most important are the loading rate, frequency, and stress amplitude [18,29]. Rocks are more easily damaged at low frequencies and high amplitude than at high frequencies and low amplitude for a given energy input [19].…”

Section: Introductionmentioning

confidence: 99%

The Mechanical Properties of Granite under Ultrasonic Vibration

Zhou

Tang

Zhang

et al. 2019

Advances in Civil Engineering

View full text Add to dashboard Cite

e new technique of using ultrasonic vibration to break hard rock is still in the experimental stage, but it has significant potential for improving the efficiency of hard rock crushing. We have analyzed the mechanical properties of granite under ultrasonic vibration and the characteristics of the damage produced. is was achieved by using an ultraloading device to apply continuous and discontinuous ultrasonic vibrations, respectively, to 32 mm diameter and 72 mm high granite samples. An ultradynamic data acceptor combined with strain gauges was used to monitor the strain of the granite in real time, and the elastic-plastic deformation behavior of the granite under ultrasonic vibration was observed. e results of this experiment indicate that the granite samples underwent elastic deformation, plastic deformation, and damage during this process. e samples first experienced compressive deformation with no obvious rupturing. As the vibration continued, the deformation finally became tensile, and significant fragmentation occurred. e mechanical properties of granite under ultrasonic vibration are analyzed in detail on the basis of these results, and the basis for selecting a vibration frequency is discussed.

show abstract

Experimental Study on Mechanical and Acoustic Emission Characteristics of Rock-Like Material Under Non-uniformly Distributed Loads

Cited by 142 publications

References 28 publications

Numerical Study of the Mechanical and Acoustic Emissions Characteristics of Red Sandstone under Different Double Fracture Conditions

Numerical Study of the Mechanical and Acoustic Emissions Characteristics of Red Sandstone under Different Double Fracture Conditions

Analysis of Mechanical and Acoustic Emission Characteristics of Rock Materials with Double‐Hole Defects Based on Particle Flow Code

The Mechanical Properties of Granite under Ultrasonic Vibration

Contact Info

Product

Resources

About