Effects of Water and Cyclic Loading on Ultrasonic and Mechanical Properties of Sandstone: An Experimental Study

Abstract

In this study, the water absorption, mechanical properties, and energy evolution characteristics of sandstone were examined through experimental and theoretical analysis. The P-wave velocity was found to initially decrease, then increased with immersion time and water content. The water absorption rates of three sandstone specimens decreased with immersion time and water content. The post-peak deformation of the sandstone changed from brittle failure to strain softening. With the increase in water content, the peak strength and loading Young’s modulus per cycle decreased. The loading Young’s modulus showed that the unloading stress and increment of unloading stress nonlinearly increased with the number of cycles and decreased before peak strength. With the increase in the number of cycles, residual strains of the sandstone specimens decreased slightly initially and then increased, while the elastic strains increased before peak strength and then decreased at the post-peak stage. With the increase in unloading stress, the energy densities nonlinearly increased. At the same unloading stress, an increase in water content led to an increase in the input energy density and energy ratios of the sandstone specimens.

Experimental study on the quasi-static and dynamic tensile behaviour of thermally treated Barakar sandstone in Jharia coal mine fire region, India

“…Rao et al 50 found a decrease from 2.21 to 1.17 in the temperature range of 250–300 °C. Whereas, Chen et al 51 observed the tensile strength reduction from 1.17 to 0.91 in the temperature range of 200–800 °C. Similarly, Yang et al 39 found a reduction of tensile strength from 1.28 to 0.43 within the temperature range of 500–900 °C.…”

A Review of the Evolution Characteristics and Argillization of Clay Interbeds in Rockslides

“…If the temperature exceeded 800 degrees, sandstone would completely change from shear failure or tensile failure to total collapse. But before 800 degrees, the shear strength of sandstone only fluctuated slightly [32]. The peak shear strength, residual shear strength and terminal normal stress all display an exponential variation with temperature, i.e., initial fluctuations or a slight increase, then a dramatic decrease, achieving a threshold temperature of 400 • C. The secant peak shear stiffness declines by 43.79-70.48% in a temperature range of 400-800 • C due to enhanced ductility and decreasing peak shear strength [33].…”