Next Article in Journal
Continuous Hydrothermal Liquefaction of Biomass in a Novel Pilot Plant with Heat Recovery and Hydraulic Oscillation
Previous Article in Journal
A Novel Step-Up Converter with an Ultrahigh Voltage Conversion Ratio
Previous Article in Special Issue
A Novel Model Incorporating Geomechanics for a Horizontal Well in a Naturally Fractured Reservoir
Article Menu
Issue 10 (October) cover image

Export Article

Open AccessArticle
Energies 2018, 11(10), 2694; https://doi.org/10.3390/en11102694

Effect of Intermediate Principal Stress on the Strength, Deformation, and Permeability of Sandstone

1
State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China
2
College of Resource and Environmental Sciences, Chongqing University, Chongqing 400030, China
3
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou 221116, China
4
Deep Earth Energy Research Laboratory, Department of Civil Engineering, Monash University, Melbourne, VIC 3800, Australia
*
Author to whom correspondence should be addressed.
Received: 4 September 2018 / Revised: 17 September 2018 / Accepted: 25 September 2018 / Published: 10 October 2018
Full-Text   |   PDF [3884 KB, uploaded 10 October 2018]   |  

Abstract

Although the mechanical behaviors and flow aspects of sandstone have been previously investigated, studies of the effect of the intermediate principal stress (σ2) on the strength, deformation, and permeability of sandstone are lacking. In this work, the mechanical behaviors and permeability of sandstone under true triaxial stress conditions were investigated using a newly developed true triaxial geophysical apparatus. The experimental results showed that with increasing σ2, the peak strength, octahedral effective normal stress, and octahedral effective shear stress of the sandstone increased, and the rate of increase decreased. This is because a larger intermediate principal stress coefficient b has an inhibitory effect on rock strength. In our study, as the ratio of σ2/σ3 increased, the specimen entered compressive strain in the σ2 direction during the first stress drop. The stress and strain path deviations occur during rock failure. The amount of deviation increased as the σ2 increased before the peak stress. This phenomenon indicates that elastic mechanics are not suitable for understanding this sandstone rock during its failure. The permeability evolution of the sandstone under true triaxial stress conditions was measured and analyzed to investigate the effect of σ2. During the complete true triaxial stress-strain experiments, the variation we found in gas seepage velocity could be divided into two stages. Before the first pressure drop, the gas seepage velocity was mainly affected by volume strain. After the first pressure drop, the seepage velocity was affected by the deviator strain, which can change the seepage channels. View Full-Text
Keywords: intermediate principal stress; rock strength; deviator strain; permeability evolution intermediate principal stress; rock strength; deviator strain; permeability evolution
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Song, Z.; Li, M.; Yin, G.; Ranjith, P.G.; Zhang, D.; Liu, C. Effect of Intermediate Principal Stress on the Strength, Deformation, and Permeability of Sandstone. Energies 2018, 11, 2694.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Energies EISSN 1996-1073 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top