Distinct element models for the coupled T-H-M processes: Theory and implementation

Ahola, M.P.; Thoraval, Alain; Chowdhury, Asadul H.

doi:10.1016/s0165-1250(96)80026-5

Cited by 4 publications

(4 citation statements)

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“…where [D] is the elastic matrix; { vp } is the viscoplastic flow rate; ij is the Kronecker function 27 ; K is the bulk modulus, where K = E/(3(1 − 2 )); is the thermal expansion coefficient; and {ΔT} is the temperature change. For a fracture, the strain increment {Δ } in Equation 11replaced by the relative displacement increment {Δu} rl, rm , which is formulated in the local coordinate system, is specified as follows:…”

Section: Governing Equation For Stress-strain Problemmentioning

confidence: 99%

“…Based on the elasto‐viscoplastic potential theory, the explicit equation of stress can be described considering a temperature change that results in thermal stress, as shown below:

false{Δ σ false} = false[D false] false(false{Δ ϵ false} - false{ϵ^{vp} false} Δ τ false) - δ_{italicij} 3 italicK α false{Δ T false}

where [ D ] is the elastic matrix; { ϵ vp } is the viscoplastic flow rate; δ ij is the Kronecker function 27 ; K is the bulk modulus, where K = E /(3(1 − 2 μ )); α is the thermal expansion coefficient; and {Δ T } is the temperature change.…”

Section: Coupled Thermo‐mechanical Fomulation Based On Cemmentioning

confidence: 99%

“…Bower and Zhang 25,26 proposed a dual‐porosity fracture flow model for thermo‐hydro‐mechanical coupling based on FEM, including stress coupling with dual‐porosity fracture and the effect of fracture hydraulic conductivity on effective stress in two dimensions. Ahola 27 presented a distinct element model of coupled thermo‐hydro‐mechanical processes to simulate thermal‐hydro coupling in filled fractures under either transient or steady‐state conditions. Comparative analysis between the discrete approach and the continuum approach was conducted to simulate thermo‐hydro‐mechanical coupling in a fractured rock mass 28 .…”

Section: Introductionmentioning

confidence: 99%

“…Currently, three numerical simulation methods for rock fracture are applied: (i) the equivalent continuum approach 1,24,29,30 ; (ii) the dual-porosity fracture approach 25,26 ; and (iii) the discrete approach. 27,28,31,32 The continuum model has been used to homogenize fracture characteristics into the rock mass in accordance with the equivalence principle; the nodal variables of a fracture are the average values of the adjacent rock mass. This approach is easy to implement but fails to consider detailed discontinuity in the fracture.…”

Section: Introductionmentioning

confidence: 99%

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Coupled thermo‐mechanical algorithm for fractured rock mass by the composite element method

Xue

Wang

et al. 2020

Numerical Meth Engineering

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To assess the influence of thermal stress on fracture deformation, a composite element algorithm of thermo-mechanical coupling for fractured rock mass is developed based on the composite element method (CEM). This study aims to investigate coupled processes associated with the (i) effect of temperature on mechanical deformation and (ii) effect of fracture aperture on heat transfer. The composite element contains fracture segments exhibiting arbitrary shapes with variables that can be interpolated from their mapped nodal variables; the mapped variables can be determined using the governing equations derived from the variational principle or virtual work principle. The proposed coupling algorithm can simulate the discontinuity of fractures, with consideration of the heat transfer of rock blocks and fractures, together with heat exchange among fractures and the adjacent rock mass. A computational mesh is generated without restrictions by explicitly embedding the fractures into the mapped composite elements, substantially simplifying the pre-process work. Analytic solutions to the transient temperature problem are examined to verify the proposed CEM algorithm. Two three-dimensional numerical models are developed to perform thermo-mechanical coupling analyses. These analyses are used to prove the advantage of the mesh handler and the reliability of the proposed algorithm. During coupling with the CEM model, the computational mesh requires no modification regardless of changes in fracture aperture. Results indicate that an increase in temperature leads to rock expansion, causing fracture deformation, which affects the general temperature of the fractured rock mass.

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Section: Governing Equation For Stress-strain Problemmentioning

confidence: 99%

“…Based on the elasto‐viscoplastic potential theory, the explicit equation of stress can be described considering a temperature change that results in thermal stress, as shown below: