A fracture damage constitutive model for fissured rock mass and its experimental verification
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ORIGINAL PAPER
A fracture damage constitutive model for fissured rock mass and its experimental verification Peng Xu 1
&
Sheng-Qi Yang 1
Received: 20 September 2015 / Accepted: 8 March 2017 # Saudi Society for Geosciences 2017
Abstract A constitutive model for fissured rock mass is established based on the deformation characteristics of microcracks under compression. The method to determine the model parameters is given. Comparative analyses between the proposed model and experimental results of siltstone indicate that this model can describe the whole process from the initial state to failure state of fissured rock mass well; this model can also simulate the initial phase in the process of fissured rock under compression well. At the same time, this model can also reflect the property of strain softening as well as the damage evolution process. Compared with previous models, this model is better able to capture the general trend which is observed experimentally. The strain energy and damage revolution of fissured rock under compression are also discussed; and the proposed model is capable of predicting the energy and damage behavior, which are in reasonably agreement with the experimental observations. Keywords Constitutive model . Damage . Fissured rock . Strain energy
Introduction Nowadays, the deformation behavior of rocks has become an interesting topic to geotechnical researchers, and more and more attention have been paid on the characteristics of * Sheng-Qi Yang [email protected] 1
State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, People’s Republic of China
deformation and the strength of rock by geotechnical engineers. The stress-strain curves of rock can represent the mechanical properties directly. Previous researchers have analyzed the typical compression curves of rocks and garnered many useful conclusions; a number of models have been created to simulate mechanical properties, such as the J-Mazars model, al-linearity model, linear elastic model, and so on (e.g., Cook 1965; Bieniawski 1967a,b,c; Jaeger and Cook 1979; Fredrich et al. 1989; Bernabe and Brace 1990; Brady and Brown 1993; Tiwari and Rao 2006). These models can reflect the stress-strain curves of rock over certain ranges and can be applied in some engineering practices, but there are still differences between the models and experimental results. With the increasing application of CT scanning and computer technology, the meso-damage combined with macro deformation of rock under compression has been analyzed (Ren et al. 2000, 2001; Yang et al. 2017). And the compression curve of rock is supposed to be divided into two parts consisting of the elastic stage and hardened stage, which reflect that adopting macroscopic damage to analyze the constitutive model of rock is not suitable. As heterogeneous materials, there are a larger number of defects such as microcracks, holes, and joints distributed in rock randomly, th
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