A structured Cam Clay model

2002 ◽  
Vol 39 (6) ◽  
pp. 1313-1332 ◽  
Author(s):  
M D Liu ◽  
J P Carter

A theoretical study of the behaviour of structured soil is presented. A new model, referred to as the Structured Cam Clay model, is formulated by introducing the influence of soil structure into the Modified Cam Clay model. The proposed model is hierarchical, i.e., it is identical to the Modified Cam Clay soil model if a soil has no structure or if its structure is removed by loading. Three new parameters describing the effects of soil structure are introduced, and the results of a parametric study are also presented. The proposed model has been used to predict the behaviour of structured soils in both compression and shearing tests. By making comparisons of predictions with experimental data and by conducting the parametric study it is demonstrated that the new model provides satisfactory qualitative and quantitative modelling of many important features of the behaviour of structured soils.Key words: calcareous soils, clays, fabric, structure, constitutive relations, plasticity.

Author(s):  
Aleksandar D. Spasojević ◽  
Dejan M. Divac ◽  
Nenad M. Šušić

2018 ◽  
Vol 4 (3) ◽  
pp. 518
Author(s):  
Tao Cheng ◽  
Yi Zhang ◽  
Keqin Yan

The character of geomaterials is affected by stress path remarkably. Under different stress paths, the stress-strain characteristics of geomaterials are difference. For the unloading path in existing engineering situation, the physical parameters and constitutive model is usually determined by loading test. The path to uninstall the actual project conditions which may be a larger error. Therefore, this work proceeding from the actual project, deep excavation of the lateral unloading condition is analysed. The tests of CTC path and RTC path on silty clay in Huangshi city of china by multi-path tri-axial plane strain are carried on in the geotechnical Engineering Laboratory of Huangshi Institute of Technology. Then, the phenomenon under the two stress paths are compared with each other and describing the differences between them. The mechanical properties in the RTC stress path is analyzed mainly. Based on the Cam-Clay model framework, then derived this material yield equation based on Cam-clay model, Laiding the foundation for the numerical analysis.


2020 ◽  
Author(s):  
Shun Wang ◽  
Wei Wu

AbstractHypoplastic constitutive models are able to describe history dependence using a single nonlinear tensorial function with a set of parameters. A hypoplastic model including a structure tensor for consolidation history was introduced in our previous paper (Wang and Wu in Acta Geotechnica, 2020, 10.1007/s11440-020-01000-z). The present paper focuses mainly on the model validation with experiments. This model is as simple as the modified Cam Clay model but with better performance. The model requires five parameters, which are easy to calibrate from standard laboratory tests. In particular, the model is capable of capturing the unloading behavior without introducing loading criteria. Numerical simulations of element tests and comparison with experiments show that the proposed model is able to reproduce the salient features of normally consolidated and overconsolidated clays.


Author(s):  
Yuki YAMAKURI ◽  
Shun-ichi KOBAYASHI ◽  
Jun SAITO ◽  
Tatsunori MATSUMOTO

2014 ◽  
Vol 51 (8) ◽  
pp. 921-933 ◽  
Author(s):  
Chao Yang ◽  
John P. Carter ◽  
Daichao Sheng

One of the most distinct characteristics of structured soils is the nonlinearity in the normal compression lines in a plot of specific volume or voids ratio against logarithmic mean or vertical effective stresses, when compared with reconstituted soils. The change in the compressibility (or compression index) with loading is attributed to structure degradation and is expressed as a function of the plastic straining. A direct description of the compression behaviour of structured soil is then established. The validity of this approach is examined via merely incorporating the newly defined normal compression line into the modified Cam-Clay constitutive model. Comparisons against a series of experiments on different types of soils illustrate the feasibility and advantage of the adopted methodology. The dependence of shear strength on the compression behaviour considered initially in critical-state soil mechanics is reemphasized here for structured soils. Analysis also indicates that the stiffness sensitivity coefficient, Sλ, should be considered together with the traditional strength (or stress) sensitivity coefficient, St (or Sσ), to better characterize the sensitivity of structured soils.


2013 ◽  
Vol 671-674 ◽  
pp. 357-362
Author(s):  
Hai Ming Liu ◽  
Jing Cao ◽  
Wei Feng Zhang

With the continuous development of urban underground space, the environmental effects of foundation pit excavation have been paid extensive close attention. Unfortunately, there are few researches in mucky soil and peaty soil. Adopted the software of FLAC-3D, the ground deformation due to the foundation pit excavation is simulated. Considering the characteristic of the soil, the Modified Cam-clay model and Mohr-coulomb model are used during the simulation. Meanwhile, the structure units are used to simulate foundation pit structure. The results of the field measurement and numerical simulation suggest that the influenced range soil is about 2.7 times of the excavation depth. Furthermore, the Modified Cam-clay model can obtain a better result to simulate the mucky soil and peaty soil in Kunming. The results can be referred to design and construct of foundation pits.


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