Mechanical Behavior, Energy Release, and Crack Distribution Characteristics of Water-Saturated Phyllite under Triaxial Cyclic Loading

Yang Zhou,Peng Li,Shengrui Su,Guowen Xu

doi:10.1155/2021/3681439

Abstract

Many geological engineering hazards are closely related to the dynamic mechanical behaviors of rock materials. However, the dynamic mechanical behaviors of phyllite are less studied. In this study, we have carried out a series of triaxial cyclic tests on dry and water-saturated phyllite by employing the MTS 815 servohydraulic testing system and AE testing equipment to reveal the mechanical behavior, energy release, and crack distribution characteristics of phyllite. Results show that phyllite is a water-sensitive rock. Water and cyclic loading substantially affect the compressive strength, crack damage stress, deformation parameters, dilatancy, energy release, and crack distribution characteristics of phyllite. Furthermore, based on the dissipated energy, a new damage variable for phyllite is established. The critical damage variable for phyllite is approximately 0.80; this variable can be used as an index to predict the failure of phyllite. The water saturation effect of phyllite is very obvious; that is, it results in the weakness of mechanical properties of phyllite and changes the AE energy release and crack distribution characteristics of phyllite. This research can provide guidance for engineering construction and disaster prevention and control.

Highlights

Rock mass is often affected by mechanical excavation, blasting, earthquake, and other dynamic loads in engineering activities. e mechanical properties of rock materials under dynamic loading have a significant influence on engineering activities
It is helpful to explore the failure mechanism of rocks and provide a basis for disaster prevention. e results of this study reveal the AE energy release characteristics of dry and saturated phyllite during excavation, which can provide guidance for monitoring the deformation and damage of surrounding rock
We have carried out a series of triaxial cyclic tests on dry and water-saturated phyllite by employing the MTS 815 servohydraulic testing system and AE testing equipment. e deformation parameters, damage stress, damage variable, AE characteristics, and failure mode of phyllite under confining pressures of 5, 10, and 20 MPa were analyzed

Summary

Introduction

Rock mass is often affected by mechanical excavation, blasting, earthquake, and other dynamic loads in engineering activities. e mechanical properties of rock materials under dynamic loading have a significant influence on engineering activities. Rock mass is often affected by mechanical excavation, blasting, earthquake, and other dynamic loads in engineering activities. E mechanical properties of rock materials under dynamic loading have a significant influence on engineering activities. Erefore, it is of great significance to study the effect of dynamic loading on the mechanical behaviors and failure mechanism of rock materials for engineering construction and disaster prevention and control. E rock mass is in a state of cyclic loading and unloading. Considerable research has been conducted on the mechanical behaviors of rocks under cyclic loading. Fuenkajorn and Phueakphum [1] studied the effect of cyclic loading on compressive strength and elastic modulus of rock salt. Liu et al [3] studied the mechanical behaviors of intermittently jointed rock models under uniaxial cyclic loading. Ning et al [7] studied the crack

Methods

Results

Discussion

Conclusion