Mechanical Behavior of Red Sandstone under Incremental Uniaxial Cyclical Compressive and Tensile Loading

Baoyun Zhao,Wei Liu,Wei Huang,Tianzhu Huang,Dongyan Liu

doi:10.1155/2017/4350437

Abstract

Uniaxial experiments were carried out on red sandstone specimens to investigate their short-term and creep mechanical behavior under incremental cyclic compressive and tensile loading. First, based on the results of short-term uniaxial incremental cyclic compressive and tensile loading experiments, deformation characteristics and energy dissipation were analyzed. The results show that the stress-strain curve of red sandstone has an obvious memory effect in the compressive and tensile loading stages. The strains at peak stresses and residual strains increase with the cycle number. Energy dissipation, defined as the area of the hysteresis loop in the stress-strain curves, increases nearly in a power function with the cycle number. Creep test of the red sandstone was also conducted. Results show that the creep curve under each compressive or tensile stress level can be divided into decay and steady stages, which cannot be described by the conventional Burgers model. Therefore, an improved Burgers creep model of rock material is constructed through viscoplastic mechanics, which agrees very well with the experimental results and can describe the creep behavior of red sandstone better than the Burgers creep model.

Highlights

In many rock engineering fields such as underground excavation, rock slope engineering, and mining, rock materials often experience cyclic loading [1]
Laboratory testing is the main method to understand the mechanical behaviors of rock mass
Two different kinds of incremental uniaxial cyclic compressive and tensile loading tests were conducted in this research, which were short-term incremental compressive and tensile cyclic loading test and incremental compressive and tensile cyclic loading creep test, as shown in Figures 5(a) and 5(b), respectively

Summary

Introduction

In many rock engineering fields such as underground excavation, rock slope engineering, and mining, rock materials often experience cyclic loading [1]. It is well known that the mechanical behavior of rocks under cyclic loads differs dramatically from that under static loads [2]. It is necessary to understand the response of rock mass under cyclic loads. Laboratory testing is the main method to understand the mechanical behaviors of rock mass. In the past several decades, extensive investigations have been carried out on the mechanical behavior of rock mass under cyclic uniaxial or triaxial compressive loads on the basis of laboratory experimental results. Based on the uniaxial cyclic compression test results, Ge et al [3] discussed the threshold of axial stress for fatigue failure of rocks. Ma et al [4] and Fuenkajorn and Phueakphum [5] investigated

Methods

Results

Conclusion