Establishment of damage statistical constitutive model of loaded rock and method for determining its parameters under freeze-thaw condition

Concrete is multi-phase composites. Due to the inhomogeneity of mechanical properties and complexity of physical properties, constitutive relations of concrete are more complicated. Starting from irreversible thermodynamics theory, internal state variable theory and nonlocal field theory, non-local damage constitutive model of concrete under freeze-thaw action is established in this paper. In the model, non-local influence functions are discussed which are used to describe interplay of damage between adjacent point.

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Damage Model and Damage Mechanical Characteristics of Loaded Rock under Freeze-Thaw Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.168-170.658 ◽

2010 ◽

Vol 168-170 ◽

pp. 658-662 ◽

Cited By ~ 2

Author(s):

Hui Mei Zhang ◽

Geng She Yang

Keyword(s):

Mechanical Properties ◽

Structural Damage ◽

Damage Mechanics ◽

Coupling Effect ◽

Damage Model ◽

Engineering Structures ◽

Freeze Thaw ◽

Thaw Cycle ◽

Loaded Rock ◽

Total Damage

Considering the heterogeneous characteristics of rock at mesoscopic level, the damage propagation constitutive relation and evolution equation of freeze-thaw and loaded rock were established by using the theory of macro phenomenological damage mechanics and the generalized theory of strain equality. The evolutionary mechanisms of micro-structural damage and materials mechanical properties for the loaded rock were discussed under freeze-thaw condition, verified by experimental results of the freeze-thaw cycle and compression test of rock. It is shown that the freeze-thaw and loaded damage model can represent the complicated relations among the freeze-thaw, load and the damage inside the rock, reveal the coupling failure mechanism of macroscopic rock under the freeze-thaw and load from the micro-damage evolution. The combined effect of freeze-thaw and load exacerbates the total damage of rock with obvious nonlinear properties, but the coupling effect weakens the total damage. The lithology and initial damage state of the freeze-thaw and loaded rock in engineering structures in cold regions determine the weights of influence factors to mechanical properties, including environmental factor, loading factor and the coupling effects, so the rock performances different damage mechanical characteristic.

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A Damage Constitutive Model of Rock Subjected to Freeze-Thaw Cycles Based on Lognormal Distribution

Advances in Civil Engineering ◽

10.1155/2021/6658915 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Hang Lin ◽

Linyuan Liang ◽

Yifan Chen ◽

Rihong Cao

Keyword(s):

Mechanical Properties ◽

Constitutive Model ◽

Lognormal Distribution ◽

Constitutive Models ◽

Strain Curve ◽

Statistical Distribution ◽

Freeze Thaw ◽

Accurate Quantitative Analysis ◽

Distribution Parameters ◽

Damage Constitutive Model

The constitutive model of rock is closely connected with the mechanical properties of rock. To achieve a more accurate quantitative analysis of the mechanical properties of rock after the action of freeze-thaw cycles, it is necessary to establish the constitutive models of rock subjected to freeze-thaw cycles from the view of rock damage. Based on the assumption of rock couple damage, this study established a statistical damage constitutive model of rock subjected to freeze-thaw cycles by combining the lognormal distribution, which is commonly used in engineering reliability analysis, and the strain strength theory. Then, the coordinates and derivative at the peak of the stress-strain curve of the rock after the action of freeze-thaw cycles were obtained through experiments to solve the statistical distribution parameters με and S of the model, whereafter, the theoretical curves by the established model were compared with the experimental curves to verify the validity of it, which shows a great agreement. Finally, the sensitivity analysis of the statistical distribution parameters was implemented. The results indicate that με reflects the strength of the rock, which shows a positive relation, and S stands for the brittleness of the rock, which shows a negative relation.

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Uniaxial Compression Fractal Damage Constitutive Model of Rock Subjected to Freezing and Thawing

Periodica Polytechnica Civil Engineering ◽

10.3311/ppci.15313 ◽

2020 ◽

Author(s):

Shengtao Zhou ◽

Nan Jiang ◽

Xuedong Luo ◽

Wen Fang ◽

Xu He

Keyword(s):

Mechanical Properties ◽

Constitutive Model ◽

Uniaxial Compression ◽

Residual Strength ◽

Structural Damage ◽

Compression Fracture ◽

Peak Strain ◽

Freeze Thaw ◽

Deformation Stage ◽

Damage Constitutive Model

Mechanical properties of the rock in the cold regions are often affected by freeze-thaw cycles and loads. It is of great theoretical significance and engineering value to establish a uniaxial compression damage constitutive model of the rock under freeze-thaw cycles that can reflect the relationship between macroscopic and mesoscopic structural damage. In this paper, macroscopic and mesoscopic methods are combined with statistical methods to quantitatively analyze the damage degree of rock under freeze-thaw cycles and loads. Combined with the fractal features of the macroscopic image of the section, a fractal damage constitutive model considering the residual strength of rock is established. In addition, the model is subsequently verified by the experiment. The experiment shows that the mechanical properties of rocks subjected to freeze-thaw cycles and loads are determined by freeze-thaw damage variables, load damage variables, and their coupling effects. As the number of freeze-thaw cycles increases, the uniaxial compressive strength and elastic modulus of rocks decrease, and peak strain increases. By using the fractal dimension of the compression fracture surface as a bridge considering the residual strength of the rock, the constitutive model can better reflect the compaction stage, elastic deformation stage and plastic deformation stage of the uniaxial compression process of the freeze-thaw rocks.

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Damage constitutive model of concrete under repeated load after seawater freeze-thaw cycles

Construction and Building Materials ◽

10.1016/j.conbuildmat.2019.117560 ◽

2020 ◽

Vol 236 ◽

pp. 117560 ◽

Cited By ~ 2

Author(s):

Wen-Liang Qiu ◽

Fei Teng ◽

Sheng-Shan Pan

Keyword(s):

Constitutive Model ◽

Freeze Thaw ◽

Damage Constitutive Model ◽

Repeated Load

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A Constitutive Model for Rock Joints under Cyclic Loading

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.243-249.2211 ◽

2011 ◽

Vol 243-249 ◽

pp. 2211-2215

Author(s):

Dong Mei Yang ◽

Xiang Bo Qiu

Keyword(s):

Constitutive Model ◽

Mechanical Behaviour ◽

Rock Joint ◽

Joint Stiffness ◽

Constitutive Models ◽

Jointed Rock ◽

Rock Joints ◽

Cyclic Loads ◽

Loaded Rock ◽

Good Agreement

Cyclic loads are commonly encountered in geotechnical engineering; however most constitutive models do not account for the effect that such loads can have on the mechanical behaviour of soils and rocks. This work is concerned with the behaviour of jointed rock and, as the overall mechanical behaviour of jointed rock is usually dominated by the mechanical behaviour of the joints, it is focused on the behaviour of rock joints under cyclic loads. In particular, an extension of the existed constitutive model for cyclically loaded rock joints is presented. Variations of rock joint stiffness in both the normal and the shear directions of loading due to surface degradation are taken into account. The degradation of asperities of first and second order is considered, while a new relation is proposed for the joint stiffness in the normal direction during unloading. Numerical simulation results show good agreement of model predictions with existing experimental results.

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