Experimental Study on Physical and Dynamic Mechanical Properties of Temperature‐Water Coupled Sandstone

In order to study the impact of fracture thickness on the dynamic mechanical properties of rock specimens, impact compression tests on prefabricated sandstone specimens with different fracture thicknesses and intact specimens were carried out by using a split Hopkinson pressure bar (SHPB) test device, and the dynamic mechanical parameters of the fractured sandstone specimens were obtained. The results showed that the dynamic stress–strain curves of the prefabricated fractured sandstone specimens are similar to those of the intact sandstone specimens, which can be divided into three stages: elasticity, plasticity, and failure. With the increase in the thickness of prefabricated cracks, the dynamic compressive strength of the sandstone specimens decreases in a quadratic function, the dynamic strain decreases in a power exponential function, and the dynamic elastic modulus decreases linearly. Attempts were made to quantitatively analyze the crushing degree of sandstone specimens. The average particle size of the crushed specimens was negatively correlated with the thickness of prefabricated cracks, and the fractal dimension was linearly negatively correlated with the dynamic compressive strength. The 1.5–2.5 mm prefabricated fractured sandstone specimens produced airfoil cracks and secondary cracks; the 3–3.5 mm prefabricated fractured specimens produced airfoil cracks, coplanar secondary cracks, and secondary oblique cracks; and the complete specimens were subjected to axial failure to produce axial cracks.

Section: Introductionmentioning

confidence: 99%

Analysis of the Fracture Characteristics and Crack Propagation Mechanism of Fractured Sandstone under Dynamic Loading

Ping,

2024

“…Gao et al [29] analyzed the mechanical properties of sandstone under the joint coupling of temperature, stress, and water but only performed static tests. Ping et al [30] only studied the dynamic properties of sandstone under temperature-water coupling but did not perform relevant tests on the sandstone under a combination of dynamic and static loading.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Dynamic and Static Combined Dynamics of Temperature–Water-Coupled Sandstone and Energy Consumption Analysis

Ping,

Hu,

et al. 2024

In order to study the dynamic properties of temperature–water-coupled sandstone under axial pressure, impact compression tests were carried out on sandstone samples after temperature–water coupling under eight types of axial pressure (0.5~4.0 MPa) loading as well as no axial pressure loading by using the split-Hopkinson pressure bar (SHPB) test set. The results showed that the mass, volume, and density of the sandstone specimens increased by 0.57%, 0.37%, and 0.20%, respectively, after temperature–water coupling. With increasing axial pressure, the dynamic compressive strength of temperature–water-coupled sandstone samples decreased as a linear function, the dynamic strain increased as a quadratic function, the dynamic modulus of elasticity decreased as a quadratic function, and the average strain rate increased as an exponential function, indicating a strong strain rate effect. From the energy point of view, as the axial pressure increases, the absorption energy of the sample increases, the reflection energy gradually decreases, the crushing degree of the sample increases, and the size of the broken pieces decreases; the average particle size of the sandstone sample pieces decreases quadratically with the increase in the absorption energy and linearly with the increase in the axial pressure.

“…Additionally, the strain rate and granite's dynamic compressive strength have a favorable correlation at high temperatures. Ping et al [16] analyzed the sandstone's mechanical properties under different loading rates and six temperature conditions (25,200,400, 600, 800, 1000 • C). The correlation between dynamic peak stress and peak strain and loading rate is positively correlated under the same temperature conditions, while the correlation between dynamic elastic modulus and temperature is opposite.…”

Section: Introductionmentioning

confidence: 99%

Experiments on the Coal Measures Sandstone’s Dynamic Mechanical Parameter Characteristics under the Combined Action of Temperature and Dynamic Load

Zhao,

Wang,

Chen

2023

This paper conducts impact dynamics experiments on coal measures sandstone in a deep mine via the established dynamic load and temperature split Hopkinson pressure bar (SHPB) experimental system. Firstly, the experimental conditions for the impact dynamics of fine sandstone were determined, with temperatures of 18, 40, 60, 80, and 100 °C, an axial static load range of 1–9 MPa, and a preset bullet incidence velocity of 1.0–5.0 m/s. Secondly, based on the analysis of the basic parameters and physical composition, the dynamic stress and strain responses of fine sandstone under different experimental conditions were obtained, and the change mechanism of its dynamic mechanical process was theoretically analyzed. When the temperature rose from 18 °C to 100 °C, the dynamic peak stress of fine sandstone increased from 36.04 MPa to 73.41 MPa, with an increase of 103.7%. At a temperature of 40 °C, when the axial static load increased from 1 MPa to 9 MPa, the dynamic stress peak of fine sandstone increased from 57.25 MPa to 80.01 MPa, and the corresponding peak strain also showed an increasing trend. The experiment analyzed the variation characteristics of dynamic stress in fine sandstone under the combined action of different strain rates or bullet incidence velocities and different temperatures. In the strain rate range of 47.1 s−1 to 140.9 s−1, there was a significant strain rate effect on the dynamic peak stress and peak strain of fine sandstone, which increased with the increase of strain rate. The study found a polynomial relationship between the dynamic mechanical parameters of fine sandstone and the impact of experimental parameters, with a coefficient of determination greater than 0.9. A dynamic stress constitutive model for fine sandstone under one-dimensional stress state under dynamic load and temperature action was established, and the model validation and parameter determination of dynamic stress changes in fine sandstone under different temperature conditions were carried out. The research results provide a new experimental method for the static and dynamic mechanical analysis of coal and rock masses under complex geological conditions and can provide a basic reference for the prevention and control of dynamic disasters in deep mining processes.