A Novel Rock Contact Model Considering Water-Softening and Chemical Weathering Effects
For rock structures exposed in the natural condition, chemical weathering and water softening are thought to be the main reasons for its strength degradation thus it is of great value to analyze the mechanism. This paper introduces a novel composite conta
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Abstract For rock structures exposed in the natural condition, chemical weathering and water softening are thought to be the main reasons for its strength degradation thus it is of great value to analyze the mechanism. This paper introduces a novel composite contact model for rock materials considering the short-term water softening and long-term chemical degradation effects. The mechanical behavior of the bond model is obtained by the Discrete Element Method (DEM) simulation of the composite bond under different load patterns (e.g. compression, tensile and shear load). The water softening and chemical weathering effects are then imported into the bond model and its mechanical behavior under normal, shear and torsion directions are analyzed. Finally, the composite contact model is established which could be used in DEM simulations to model the strength degradation of rock materials under water softening and chemical weathering attacks.
1 Introduction Rock materials have played important roles in construction engineering and their mechanical behavior has been investigated by both experiments and numerical simulations over a long period [1]. As rocks are exposed in natural environment, the mechanical behavior are influenced by water-rock interaction and chemical weathering process. A series of practical problems, such as underground storage of M. Jiang (&) W. Liu Z. Liao State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China e-mail: [email protected] M. Jiang W. Liu Z. Liao Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China M. Jiang W. Liu Z. Liao Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China © Springer Science+Business Media Singapore 2017 X. Li et al. (eds.), Proceedings of the 7th International Conference on Discrete Element Methods, Springer Proceedings in Physics 188, DOI 10.1007/978-981-10-1926-5_48
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hazardous waste [2], have aroused public concern of degradation process on this kind of rock materials. There are mainly two aspects with regard to the water-rock interaction process, i.e. in the micro chemical composition point of view analyzing the altering of mineral composition [3–5] and in the macro mechanical point of view analyzing the weakening of physical mechanical properties after the water saturation [6–8]. The results show that the water will introduce a degradation effect to the mechanical behavior of rocks. The influences show, in the macro point of view, with the decrease of the strength and the elastic modulus and, in the micro point of view, with the melting of bonding materials and the increasing of void ratio. For the chemical weathering process, varieties of mathematical models [9, 10] and experiments [11, 12] have been provided to predict the weathering rate, structural alteration and/or strength degradation. It is clear that weathering is a long proc
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