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Mathematical Problems in Engineering
Volume 2018, Article ID 1916761, 11 pages
Research Article

Calculation of Tangent Modulus of Soils under Different Stress Paths

1School of Civil Engineering, Chang’an University, Xi’an 710061, China
2Land, Urban Construction and Water Affairs Bureau of Chancheng District, Foshan 528000, China

Correspondence should be addressed to Min Huang; moc.qq@9052553441

Received 7 January 2018; Revised 11 February 2018; Accepted 5 April 2018; Published 13 May 2018

Academic Editor: Zhi-ke Peng

Copyright © 2018 Hua Huang et al. 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.


During excavation of foundation pit, soils of different sites may undergo different unloading paths. This study focuses on the tangent modulus of soil under different stress paths and provides theoretical basis for the deformation calculation of soil. In this paper, conventional triaxial compression test and consolidation unloading test were conducted with mucky soil and silty clay to obtain the deformation characteristics of soils under different stress paths. Experiment results show that the soil samples exhibit distinct stress-strain characteristics under different stress paths, but they all show nonlinearity. The initial tangent modulus increases as the consolidation confining pressure intensifies. Then, based on the test data, the power function relationship between initial tangent modulus and confining pressure under unloading was verified. Simultaneously, a hyperbola function to express stress-strain relation of soils under the consolidation unloading condition was proposed and proved. Finally, the formulas of the tangent modulus under consolidation unloading were established referring to the derivation of that in Duncan–Chang model. The theoretical calculation results agree well with the test results. It can expand the use of the Duncan–Chang model and improve its application to engineering practice.