Computational Technology Resources - CCP

Keywords: bonded particle model, elasto-plastic deformation, sandstone.

Summary

According to previous laboratory experiments and petrographic analysis of sandstone, it was found that the key parameters influencing the unconfined compressive strength (UCS) are porosity and grain area ratio (GAR). However, the relationship of macroscopic properties with the microscopic ones highlights the necessity further study in exploring how the microscopic properties influence the macroscopic properties. In this study, numerical analyses based on the bonded particle model were conducted to systematically study the microscopic mechanism. After a series of tests and comparisons with the actual behaviour of sandstone, a numerical model comprised of three types of particles (grain particles GP, matrix particles MP and porous matrix particles PP) was proposed to represent the sandstone. The model has been tested for modelling sandstones and shows a good capability in simulating the behaviour of sandstone under uniaxial compression. Furthermore, the simulated variation of UCS with different GAR and porosity n is consistent with the empirical correlations founded by Jeng et al. [1].

The elasto-plastic deformation of sandstone is further explored by means of conventional triaxial tests. Simulation results demonstrate that the mechanical behaviour of sandstone has the following characteristics:

The cohesion is significantly influenced by both the GAR and the porosity. The greater the GAR and the porosity values the less the cohesion. However, for the friction angle, the influence of the GAR is insignificant, and lower porosity leads to a higher friction angle;
The elastic shear modulus increases with decreasing porosity and increasing GAR;
A series of elliptic plastic potential surfaces can be observed according to the plastic flow distribution. These elliptic surfaces are similar to those of sandstone, reported by Weng et al. [2]; and
Variations of plastic angle and plastic strain trajectory under different shear stress ratios are similar to the actual behaviour of sandstone.

References

1: F.S. Jeng, M.C. Weng, M.L. Lin, T.H. Huang, "Influence of petrographic parameters on geotechnical properties of Tertiary sandstones from Taiwan", Engineering Geology, 73, 71-91, 2004. doi:10.1016/j.enggeo.2003.12.001
2: M.C. Weng, F.S. Jeng, T.H. Huang, M.L. Lin, "Characterizing the Deformation Behavior of Tertiary Sandstones", International Journal of Rock Mechanics and Mining Science, 42, 388-401, 2005. doi:10.1016/j.ijrmms.2004.12.004

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £140 +P&P)

	Computational & Technology Resources an online resource for computational, engineering & technology publications
	not logged in - login
Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 91 PROCEEDINGS OF THE TWELFTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING Edited by: B.H.V. Topping, L.F. Costa Neves and R.C. Barros Paper 230 The Microscopic Mechanism associated with Mechanical Behaviour of Sandstone: Using a Bonded Particle Model M.C. Weng¹ and H.H. Li² ¹Department of Civil and Environmental Engineering, National University of Kaohsiung, Taiwan ²Chung Cheng Institute of Technology, National Defense University, Taiwan doi:10.4203/ccp.91.230 purchase the full-text of this paper Full Bibliographic Reference for this paper M.C. Weng, H.H. Li, "The Microscopic Mechanism associated with Mechanical Behaviour of Sandstone: Using a Bonded Particle Model", in B.H.V. Topping, L.F. Costa Neves, R.C. Barros, (Editors), "Proceedings of the Twelfth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 230, 2009. doi:10.4203/ccp.91.230 Keywords: bonded particle model, elasto-plastic deformation, sandstone. Summary According to previous laboratory experiments and petrographic analysis of sandstone, it was found that the key parameters influencing the unconfined compressive strength (UCS) are porosity and grain area ratio (GAR). However, the relationship of macroscopic properties with the microscopic ones highlights the necessity further study in exploring how the microscopic properties influence the macroscopic properties. In this study, numerical analyses based on the bonded particle model were conducted to systematically study the microscopic mechanism. After a series of tests and comparisons with the actual behaviour of sandstone, a numerical model comprised of three types of particles (grain particles GP, matrix particles MP and porous matrix particles PP) was proposed to represent the sandstone. The model has been tested for modelling sandstones and shows a good capability in simulating the behaviour of sandstone under uniaxial compression. Furthermore, the simulated variation of UCS with different GAR and porosity n is consistent with the empirical correlations founded by Jeng et al. [1]. The elasto-plastic deformation of sandstone is further explored by means of conventional triaxial tests. Simulation results demonstrate that the mechanical behaviour of sandstone has the following characteristics: The cohesion is significantly influenced by both the GAR and the porosity. The greater the GAR and the porosity values the less the cohesion. However, for the friction angle, the influence of the GAR is insignificant, and lower porosity leads to a higher friction angle; The elastic shear modulus increases with decreasing porosity and increasing GAR; A series of elliptic plastic potential surfaces can be observed according to the plastic flow distribution. These elliptic surfaces are similar to those of sandstone, reported by Weng et al. [2]; and Variations of plastic angle and plastic strain trajectory under different shear stress ratios are similar to the actual behaviour of sandstone. References 1 F.S. Jeng, M.C. Weng, M.L. Lin, T.H. Huang, "Influence of petrographic parameters on geotechnical properties of Tertiary sandstones from Taiwan", Engineering Geology, 73, 71-91, 2004. doi:10.1016/j.enggeo.2003.12.001 2 M.C. Weng, F.S. Jeng, T.H. Huang, M.L. Lin, "Characterizing the Deformation Behavior of Tertiary Sandstones", International Journal of Rock Mechanics and Mining Science, 42, 388-401, 2005. doi:10.1016/j.ijrmms.2004.12.004 purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £140 +P&P)
Back to top	©Civil-Comp Limited 2023 - terms & conditions