A composite power exponential nonlinear model of rock and soil
WANG Liqin1，2，LU Zhonggang1，SHAO Shengjun1，2
(1. School of Civil Engineering and Architecture，Xi?an University of Technology，Xi?an，Shaanxi 710048，China；
2. Shaanxi Provincial Key Laboratory of Loess Mechanics and Engineering，Xi?an University of Technology，
Xi'an，Shaanxi 710048，China)
Abstract：In the past，the stress-strain curve of rock and soil can only be described by using the different mathematical models according to its morphological type，and the description of corresponding volume deformation curve is very rare. In order to realize a unified mathematical model for the description of different stress-strain curves and volume deformation curves，a new nonlinear model called as the composite power exponential model(CPE model for short) is presented by analysing the characteristics of power function and exponential function. The determining method of each parameter is also proposed. The structural loess is studied experimentally and the curves of measured stress-strain and the volume deformation from triaxial tests with different water contents and different confining pressures are fitted by CPE model. The variation law of each parameter is analyzed. For unsaturated undisturbed loess，the CPE model of stress-strain curve of strain softening which considers water content and that of strain hardening which considers confining pressure are obtained respectively. The CPE model of volume deformation curve of shear contraction which considers confining pressure is obtained，too. The calculated curves using the above CPE models are compared with the measured ones. The result shows that the CPE model has extensive adaptability and high accuracy，which can describes the stress-strain curves of softening and hardening of different degrees and the volume deformation curves of shear expansion or shear contraction. The CPE model provides a unified mathematical model for stress-strain curves and volume deformation curve of different forms.
王丽琴1，2，鹿忠刚1，邵生俊1，2. 岩土体复合幂–指数非线性模型[J]. 岩石力学与工程学报, 2017, 36(5): 1269-1278.
WANG Liqin1，2，LU Zhonggang1，SHAO Shengjun1，2. A composite power exponential nonlinear model of rock and soil. , 2017, 36(5): 1269-1278.
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2017, Vol. 36 
