Nonlinear Young\u2019s Modulus of New Red Sandstone: Experimental Studies

Evgenii Riabokon,Mikhail Guzev,Evgenii Kozhevnikov,Mikhail Turbakov,Vladimir Poplygin,Marian Wiercigroch,Dmitrii Kobiakov

doi:10.1007/s10338-021-00298-w

Evgenii Riabokon, Mikhail Guzev + Show 5 more

Open Access

https://doi.org/10.1007/s10338-021-00298-w

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Abstract

Young’s modulus of New Red Sandstone was investigated experimentally to gain insight into its nonlinear nature. A large experimental programme was carried out by applying a controllable quasi-static and dynamic uniaxial loading to 286 dry sandstone samples of four different sizes. The static and dynamic tests, similar to those aiming at determining the uniaxial compressive strength, were conducted using the state-of-the-art experimental facilities at the University of Aberdeen including a custom-built small experimental rig for inducing a dynamic uniaxial compressive load via a piezoelectric transducer. The obtained results have confirmed a complex nature of Young’s modulus of sandstone. Specifically, under a harmonic dynamic loading, it shows strongly nonlinear behaviour, which is hardening and softening with respect to frequency and amplitude of the dynamic loading, respectively.

Highlights

Changes of geomechanical characteristics of rocks under static and dynamic loading are of significant fundamental and practical importance
The main purpose of this paper is to experimentally study the behaviour of the dynamic Young’s modulus of dry sandstone samples under uniaxial compression predominantly in the zone of linear elasticity
The results reported in [33, 34] on uniaxial compression testing of another sedimentary rock, Gosford Sandstone, with sample diameters ranging from 7 to 145 mm, showed that the uniaxial compressive strength (UCS) of the Gosford Sandstone rose with the increase in sample diameter up to 66 mm and fell steadily for larger diameters

Summary

A E Edyn F Fex Fmax Fmin Fmax av Fmin av Frig max Fdyn Fst d

Amplitude of the dynamic load (N) Young’s modulus (Pa) Dynamic component of Young’s modulus (Pa) Load (N) External load (N) Maximum force (N) Minimum force (N) Upper load limit of the linear elastic zone (N) Lower load limit of the linear elastic zone (N) Load limit of the rig (N) Dynamic load (N) Static preload (N) Diameter of a sample (m). Length of a sample (m) Maximum length of a sample (m) Minimum length of a sample (m) Contraction of a sample (m) Maximum radius of a sample (m) Minimum radius of a sample (m) Radial displacement (m) Linear radial strain (−) Linear axial strain (−) Poisson’s ratio (−) Average Poisson’s ratio (−) Upper strength limit of a linear elastic zone (Pa) Lower strength limit of a linear elastic zone (Pa) Average uniaxial compressive strength (Pa) Uniaxial compressive strength (Pa) Frequency (Hz) Rock constants (–, –, N, GPa/Hz2, GPa)

Introduction

Experimental Methodology

Dynamic Tests

Nature of Young’s Modulus of New Red Sandstone

Findings

Closing Remarks