Do the normal compression lines of cemented and uncemented geomaterials run parallel or converge to each other after yielding?

Abstract

Whether the normal compression lines (NCLs) of cemented and uncemented materials run parallel or converge to each other after yielding is a fundamental yet controversial issue in the study of compression behaviour of geomaterials. An effort is made here to clarify the question by means of the distinct element method (DEM) combined with available experimental observations. In the DEM simulations, the effects of cement content, void ratio, bond elastic modulus, bond strength and bond distribution on the compression curves are considered. In addition, the microscopic mechanical responses, including bond breakage events, deviatoric fabric and stress shared by bonded part or unbonded part, are investigated. The DEM simulations show that the NCLs for all the cemented specimens run parallel with the NCL for the uncemented specimen within the range of stresses adopted in the study, which is not influenced by the aforementioned factors. Through comparing the DEM results in this study, previous 3D DEM data and experimental observations, it can be preliminarily concluded that the interactions between cement breakage and particle crushing determine the convergence or non-convergence of NCLs. The NCLs of the cemented and uncemented sands run parallel for the strong-particle case, while those tend to converge for the fragile-particle case.

Keywords:

• Cemented sands
• distinct element method
• isotropic compression test
• bond breakage
• particle crushing

Acknowledgments

The authors would also like to thank Dr. Zhifu Shen from Nanjing Tech University, China for his valuable discussions on some work in the article.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the State Key Lab. of Disaster Reduction in Civil Engineering; under Grant No. 300 SLDRCE14-A-04; National Natural Science Foundation of China; under Grant No. 51579178.