Study on Dynamic Characteristics of Diorite Under Dry–Wet Cycle

Abstract

During the construction of tunnels in the central and western regions of China, diorite is frequently affected by vibration, blasting and water which will lead to the questions of the quality and operational safety of project. However, there are few studies on the dynamic characteristics of diorite under the action of dry-wet cycles. Therefore, this paper selected the gray-green altered diorite from Ning shan County, Shaanxi Province, China, mainly composed of plagioclase, and used the Slit Hopkinson pressure bar (SHPB) to study the effect of dry-wet cycle on the dynamic characteristics of Diorite. The test results show that the strength decay rate of the peak strength of diorite is the maximum under 1-3 dry-wet cycles, then decreases gradually. The dynamic elastic modulus of diorite dropped by 35.02% after three dry-wet cycles, accounting for 98.45% of the total attenuation. Compared the test result of three dry-wet cycles, the decrease volumes of the stress growth rate of diorite are the largest after six dry-wet cycles. Because of the actions of the dry-wet cycles, the growth rate of the rapid growth stage of the reflected energy-time history curve reduces and the growth rate of the rapid growth stage of the transmitted energy-time history curve improves. Under the action of the dry-wet cycles, the dissipation energy ratio gradually decreases, and the decrease of energy consumption density follows a negative exponential function relationship. Under the action of multiple dry-wet cycles, the tension and compression stress frequently change between the particles of rock, resulting in a significant increase of micro-cracks and an obvious degradation effect on the dynamical properties of diorite. KeywordsDry-wet cycle • Hopkinson pressure bar test • Dynamic uniaxial compressive strength • Dynamic elastic modulus • Stress growth rate • Energy analysis * Jiangbo Xu

Experimental Study of the Dynamic Mechanical Behavior and Degradation Mechanism of Red Sandstone in Acid Dry-Wet Cycles

“…Water-rock chemical action causes more damage to rocks than physical action, and chemical damage is tightly connected to rock mineral composition, solution acidity and alkalinity, ion concentration, and other parameters. When an aqueous solution becomes acidic, hydrogen ions in the solution can react with iron/calcium 6 Geofluids cements, feldspars, carbonates, silicates, and other compounds [21]. In neutral aqueous solutions, these are difficult to dissolve.…”

Dynamic Tensile Failure Characteristics and Energy Dissipation of Red Sandstone under Dry–Wet Cycles

“…In the SHPB test, the energy that is absorbed by the specimen primarily consists of three components: the energy absorbed by the crack propagation and failure of the specimen, the energy consumed by the splash of fragments after the impact failure of the specimen, and other forms of energy consumption (such as friction energy consumption and heat energy consumption). Studies have shown that the energy used for crack propagation and rock failure generally accounts for more than 95% of the total energy, and the proportion of other energy forms is less than 5% [34]. In the following studies, the energy absorbed by the specimen can be used to replace the energy consumption of the crushing.…”

On the effect of water content on fatigue mechanical behaviors of mud-shale under stress disturbance conditions

“…Although the influences of fatigue loading parameters on rock damage and fracture have been widely studied, most of the studies are focusing on intact and pre-flawed hard rock, such as granite, marble, basalt, limestone, diorite, and also the block-in-matrixrocks (Al-Shayea 2004;Zhou et al, 2015;Xu et al, 2021;Wang et al, 2022d;Wang et al, 2023). Investigations on the fatigue mechanical behaviors of water-sensitive rock, e.g., mud-shale in this work, exposed to cyclic loads are relatively less, especially the influence of water content on the deformation and damage evolution are rarely reported.…”