The Experts below are selected from a list of 225810 Experts worldwide ranked by ideXlab platform
Mohsen Soleiman Dehkordi - One of the best experts on this subject based on the ideXlab platform.
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application of the cohesion softening friction softening and the cohesion softening friction hardening models of rock Mass Behavior to estimate the specific energy of tbm case study amir kabir water conveyance tunnel in iran
Geotechnical and Geological Engineering, 2019Co-Authors: Majid Mirahmadi, Mohsen Soleiman DehkordiAbstract:The specific energy (SE) of an excavation is an important factor to consider in economic and technological investigations of mechanical excavation projects using a tunnel-boring machine (TBM). SE is defined as the energy consumed during excavation of per unit volume of rock Mass, and it can be determined in real time from the data recording the performance of a TBM. Several experimental, empirical, and analytical methods have been developed to predict SE based on rock Mass and machine parameters. In this study, a new empirical method is proposed to predict SE based on the strain energy ratio of rock Mass (Ψ). This is defined as the ratio of the residual post peak strain energy to the stored pre peak strain energy of the rock Mass. It depends on three important parameters, namely rock Mass properties, intact rock parameters, and rock Mass Behavior models. In this study, to estimate the strain energy ratio of rock Mass, two post peak rock Mass Behavior models—cohesion softening–friction softening (CSFS) and cohesion softening–friction hardening (CSFH)—were used. Based on actual data from the Amir–Kabir water conveyance tunnel project, the relationships between the SE of TBM and the strain energy ratio were investigated. Due to different rock Mass qualities in the tunnel route, classification of rock Mass according to Hoek and Brown’s proposal was carried out, and the correlation between the mentioned parameters in each class was studied. The results showed a direct relationship between the parameters, and the best relationships in poor and moderate rock Mass (geological strength index [GSI] 70) because of its ability to modify the brittle Behavior of brittle rock Mass.
Hong Hao - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of blast induced stress waves in a rock Mass with anisotropic continuum damage models part 1 equivalent material property approach
Rock Mechanics and Rock Engineering, 2002Co-Authors: Hong Hao, Yingxin ZhouAbstract:This paper uses the concept of anisotropic damage mechanics to analyze dynamic responses of a granite site under blasting loads. An anisotropic continuum damage model is suggested to model rock Mass Behavior under blasting loads. The effects of existing cracks and joints in the rock Mass are considered by using equivalent rock material properties obtained from both field and laboratory test data. The anisotropic damage accumulations are simulated by continuous degradation of equivalent material stiffness and strength during loading process and are calculated using the exponential function with respect to the principal tensile strain in three directions. The suggested models are programmed and linked to an available computer program Autodyn3D through its user's subroutine capability. Stress wave propagation and damage zone in the rock Mass induced by underground explosions are simulated. Numerical results of damaged area, peak particle velocity and acceleration attenuation as well as acceleration time histories and Fourier spectra are compared with those from independent field tests.
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numerical analysis of blast induced stress waves in a rock Mass with anisotropic continuum damage models part 2 stochastic approach
Rock Mechanics and Rock Engineering, 2002Co-Authors: Hong Hao, C C SeahAbstract:Summary This paper reports the second part of the study carried out by the authors on the under- ground explosion-induced stress wave propagation and damage in a rock Mass. In the accompanying paper reporting the first part of the study, equivalent material properties were used to model the eects of existing cracks and joints in the rock Mass. The rock Mass and its properties were treated as deterministic. In this paper, existing random cracks and joints are modeled as statistical initial damage of the rock Mass. In numerical calculation, an anisotropic continuum damage model including both the statistical anisotropic initial damage and cumulative damage dependent on principal tensile strain and stochastic critical tensile strain is suggested to model rock Mass Behavior under explosion loads. The statisti- cal estimation of stress wave propagation in the rock Mass due to underground explosion is evaluated by Rosenblueth's point estimate method. The suggested models and statistical solution process are also programmed and linked to Autodyn3D as its user's subroutines. Numerical results are compared with the field test data and those presented in the accom- panying paper obtained with equivalent material property approach.
Majid Mirahmadi - One of the best experts on this subject based on the ideXlab platform.
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application of the cohesion softening friction softening and the cohesion softening friction hardening models of rock Mass Behavior to estimate the specific energy of tbm case study amir kabir water conveyance tunnel in iran
Geotechnical and Geological Engineering, 2019Co-Authors: Majid Mirahmadi, Mohsen Soleiman DehkordiAbstract:The specific energy (SE) of an excavation is an important factor to consider in economic and technological investigations of mechanical excavation projects using a tunnel-boring machine (TBM). SE is defined as the energy consumed during excavation of per unit volume of rock Mass, and it can be determined in real time from the data recording the performance of a TBM. Several experimental, empirical, and analytical methods have been developed to predict SE based on rock Mass and machine parameters. In this study, a new empirical method is proposed to predict SE based on the strain energy ratio of rock Mass (Ψ). This is defined as the ratio of the residual post peak strain energy to the stored pre peak strain energy of the rock Mass. It depends on three important parameters, namely rock Mass properties, intact rock parameters, and rock Mass Behavior models. In this study, to estimate the strain energy ratio of rock Mass, two post peak rock Mass Behavior models—cohesion softening–friction softening (CSFS) and cohesion softening–friction hardening (CSFH)—were used. Based on actual data from the Amir–Kabir water conveyance tunnel project, the relationships between the SE of TBM and the strain energy ratio were investigated. Due to different rock Mass qualities in the tunnel route, classification of rock Mass according to Hoek and Brown’s proposal was carried out, and the correlation between the mentioned parameters in each class was studied. The results showed a direct relationship between the parameters, and the best relationships in poor and moderate rock Mass (geological strength index [GSI] 70) because of its ability to modify the brittle Behavior of brittle rock Mass.
C C Seah - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of blast induced stress waves in a rock Mass with anisotropic continuum damage models part 2 stochastic approach
Rock Mechanics and Rock Engineering, 2002Co-Authors: Hong Hao, C C SeahAbstract:Summary This paper reports the second part of the study carried out by the authors on the under- ground explosion-induced stress wave propagation and damage in a rock Mass. In the accompanying paper reporting the first part of the study, equivalent material properties were used to model the eects of existing cracks and joints in the rock Mass. The rock Mass and its properties were treated as deterministic. In this paper, existing random cracks and joints are modeled as statistical initial damage of the rock Mass. In numerical calculation, an anisotropic continuum damage model including both the statistical anisotropic initial damage and cumulative damage dependent on principal tensile strain and stochastic critical tensile strain is suggested to model rock Mass Behavior under explosion loads. The statisti- cal estimation of stress wave propagation in the rock Mass due to underground explosion is evaluated by Rosenblueth's point estimate method. The suggested models and statistical solution process are also programmed and linked to Autodyn3D as its user's subroutines. Numerical results are compared with the field test data and those presented in the accom- panying paper obtained with equivalent material property approach.
Yingxin Zhou - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of blast induced stress waves in a rock Mass with anisotropic continuum damage models part 1 equivalent material property approach
Rock Mechanics and Rock Engineering, 2002Co-Authors: Hong Hao, Yingxin ZhouAbstract:This paper uses the concept of anisotropic damage mechanics to analyze dynamic responses of a granite site under blasting loads. An anisotropic continuum damage model is suggested to model rock Mass Behavior under blasting loads. The effects of existing cracks and joints in the rock Mass are considered by using equivalent rock material properties obtained from both field and laboratory test data. The anisotropic damage accumulations are simulated by continuous degradation of equivalent material stiffness and strength during loading process and are calculated using the exponential function with respect to the principal tensile strain in three directions. The suggested models are programmed and linked to an available computer program Autodyn3D through its user's subroutine capability. Stress wave propagation and damage zone in the rock Mass induced by underground explosions are simulated. Numerical results of damaged area, peak particle velocity and acceleration attenuation as well as acceleration time histories and Fourier spectra are compared with those from independent field tests.
