Saeed Tourchi, Miguel A. Mánica, Antonio Gens, Jean Vaunat, Minh-Ngoc Vu, Gilles Armand
The paper presents the enhancement of an existing constitutive model for argillaceous hard soils-weak rocks to incorporate non-isothermal conditions to be used in coupled thermo-hydro-mechanical (THM) simulations of underground excavations subjected to temperature variations within the context of deep geological nuclear waste disposal. The proposed thermo-elastoplastic extension accounts for the effect of temperature on the yield and plastic potential functions and on the elastic stiffness. The resulting model is validated through the simulation of relevant non-isothermal laboratory tests reported in the literature. The model is then applied to the coupled THM simulation of an in situ heating test conducted at the Meuse/Haute-Marne underground research laboratory in Bure, France, excavated in the Callovo-Oxfordian claystone. Results show that the incorporation of thermal effects into the constitutive description of the host rock plays a significant role in the behaviour of the excavation when subjected to thermal loading, particularly in the evolution of the excavation fractured zone.
{"title":"A thermomechanical model for argillaceous hard soils-weak rocks: application to THM simulation of deep excavations in claystone","authors":"Saeed Tourchi, Miguel A. Mánica, Antonio Gens, Jean Vaunat, Minh-Ngoc Vu, Gilles Armand","doi":"10.1680/jgeot.23.00023","DOIUrl":"https://doi.org/10.1680/jgeot.23.00023","url":null,"abstract":"The paper presents the enhancement of an existing constitutive model for argillaceous hard soils-weak rocks to incorporate non-isothermal conditions to be used in coupled thermo-hydro-mechanical (THM) simulations of underground excavations subjected to temperature variations within the context of deep geological nuclear waste disposal. The proposed thermo-elastoplastic extension accounts for the effect of temperature on the yield and plastic potential functions and on the elastic stiffness. The resulting model is validated through the simulation of relevant non-isothermal laboratory tests reported in the literature. The model is then applied to the coupled THM simulation of an in situ heating test conducted at the Meuse/Haute-Marne underground research laboratory in Bure, France, excavated in the Callovo-Oxfordian claystone. Results show that the incorporation of thermal effects into the constitutive description of the host rock plays a significant role in the behaviour of the excavation when subjected to thermal loading, particularly in the evolution of the excavation fractured zone.","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinquan Shi, Yang Xiao, J. Antonio H. Carraro, Haoyu Li, Hanlong Liu, Jian Chu
Small-strain stiffness and stiffness anisotropy of a sand are sensitive to the sand fabric, which can be significantly affected by particle shape and cementation. In this study, multidirectional bender element and isotropic compression tests were performed on glass sands with different particle shapes and biocementation levels. The small-strain stiffness and stiffness anisotropy of the untreated and biotreated sands were systematically investigated. A natural cementation process is used to investigate the small-strain stiffness of cemented sand; this might be a potential way to replicate the mechanical behaviour of undisturbed sand with weak cementation. Test results showed that the small-strain stiffness increases with increasing sand angularity. It is proposed that shear wave velocity has different sensitivities to particle shape parameters for uncemented sands. The stiffness anisotropy increases with the increase in sand angularity and decreases with increasing stress levels at an identical void ratio state. For the lightly biocemented sands, the small-strain stiffness can be improved significantly after the biotreatment reaction with the calcite bonds among grains. The development of small-strain stiffness with stress is different for specimens with different cementation levels. The stiffness anisotropy ratio first increases and then decreases with the increase of the biocementation level, which cannot be changed even with normalisation using the parameter A in the Hardin equation.
{"title":"Anisotropic small-strain stiffness of lightly biocemented sand considering grain morphology","authors":"Jinquan Shi, Yang Xiao, J. Antonio H. Carraro, Haoyu Li, Hanlong Liu, Jian Chu","doi":"10.1680/jgeot.22.00350","DOIUrl":"https://doi.org/10.1680/jgeot.22.00350","url":null,"abstract":"Small-strain stiffness and stiffness anisotropy of a sand are sensitive to the sand fabric, which can be significantly affected by particle shape and cementation. In this study, multidirectional bender element and isotropic compression tests were performed on glass sands with different particle shapes and biocementation levels. The small-strain stiffness and stiffness anisotropy of the untreated and biotreated sands were systematically investigated. A natural cementation process is used to investigate the small-strain stiffness of cemented sand; this might be a potential way to replicate the mechanical behaviour of undisturbed sand with weak cementation. Test results showed that the small-strain stiffness increases with increasing sand angularity. It is proposed that shear wave velocity has different sensitivities to particle shape parameters for uncemented sands. The stiffness anisotropy increases with the increase in sand angularity and decreases with increasing stress levels at an identical void ratio state. For the lightly biocemented sands, the small-strain stiffness can be improved significantly after the biotreatment reaction with the calcite bonds among grains. The development of small-strain stiffness with stress is different for specimens with different cementation levels. The stiffness anisotropy ratio first increases and then decreases with the increase of the biocementation level, which cannot be changed even with normalisation using the parameter A in the Hardin equation.","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135923555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To investigate the behaviour of sands at the particle-scale during shear failure, a series of triaxial compression tests was conducted on dry sands with varying confining stresses and relative densities. These tests were complemented by acoustic emission (AE) monitoring to analyse the frequency-dependent AE signals and characterise particle interactions in terms of crushing (>100 kHz) and rearrangement (<100 kHz). The results reveal a linear relationship between the relative breakage index (B r ) and the logarithm of cumulative high-frequency AE hits, regardless of the relative density. With this, particle crushing, as well as particle rearrangement, is demonstrated to occur throughout the entire shearing. Particle crushing increases more rapidly to prevail from the very beginning to the general yield, thereafter at a slower increasing rate to become less predominant. Its evolution in the post-peak regime is related to the failure pattern, which accumulates at a constant and most rapid rate when the specimen is ‘barrelling’; however, it decays rapidly in the presence of shear banding and eventually reaches an equilibrium state with particle rearrangement once the critical stress state is attained. Accordingly, two types of approximate evolution trends are suggested to estimate particle crushing upon shearing depending on the failure patterns.
{"title":"Frequency dependence of acoustic emission with particle interaction and failure process in dry sands during triaxial compression","authors":"Wenli Lin, Ang Liu, Wuwei Mao, Junichi Koseki","doi":"10.1680/jgeot.22.00407","DOIUrl":"https://doi.org/10.1680/jgeot.22.00407","url":null,"abstract":"To investigate the behaviour of sands at the particle-scale during shear failure, a series of triaxial compression tests was conducted on dry sands with varying confining stresses and relative densities. These tests were complemented by acoustic emission (AE) monitoring to analyse the frequency-dependent AE signals and characterise particle interactions in terms of crushing (>100 kHz) and rearrangement (<100 kHz). The results reveal a linear relationship between the relative breakage index (B r ) and the logarithm of cumulative high-frequency AE hits, regardless of the relative density. With this, particle crushing, as well as particle rearrangement, is demonstrated to occur throughout the entire shearing. Particle crushing increases more rapidly to prevail from the very beginning to the general yield, thereafter at a slower increasing rate to become less predominant. Its evolution in the post-peak regime is related to the failure pattern, which accumulates at a constant and most rapid rate when the specimen is ‘barrelling’; however, it decays rapidly in the presence of shear banding and eventually reaches an equilibrium state with particle rearrangement once the critical stress state is attained. Accordingly, two types of approximate evolution trends are suggested to estimate particle crushing upon shearing depending on the failure patterns.","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135923735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kyeong-Cheol Kim, Ho-Jong Kim, Kang-Hyun Kim, Jong-Ho Shin
Inflatable steel-tube rock bolts are useful as they can introduce a pullout resistance immediately after installation and do not cause a loss of frictional force under groundwater existing environment. The anchoring mechanism and pullout resistance of the inflatable steel-tube has been basically explained through theoretical studies. The contact behaviour between the tube and borehole rock is essentially geometrically nonlinear and elasto-plastic, which cannot be properly considered in theoretical approaches. In this study, the contact behaviour of inflatable steel-tube rock bolts was investigated through a novel modelling based on the contact theory. A validating representative model test for an inflatable steel-tube rock bolts was performed and successfully reproduced through the contract modelling method. It is revealed that the contact behaviour was found to significantly differ from the theoretical assumptions. Parametric analyses were carried out to investigate the effect of influencing factors such as the diameter ratio, the elastic modulus and maximum installation pressure that cannot be considered in the theoretical model. It was found that the state of full inflation is the stress turning point where the general tube behaviour changes from mainly plastic to elastic. The maximum contact stress was obtained immediately before full inflation.
{"title":"Numerical modelling of inflatable steel-tube rock bolt considering nonlinear contact behaviour","authors":"Kyeong-Cheol Kim, Ho-Jong Kim, Kang-Hyun Kim, Jong-Ho Shin","doi":"10.1680/jgeot.23.00020","DOIUrl":"https://doi.org/10.1680/jgeot.23.00020","url":null,"abstract":"Inflatable steel-tube rock bolts are useful as they can introduce a pullout resistance immediately after installation and do not cause a loss of frictional force under groundwater existing environment. The anchoring mechanism and pullout resistance of the inflatable steel-tube has been basically explained through theoretical studies. The contact behaviour between the tube and borehole rock is essentially geometrically nonlinear and elasto-plastic, which cannot be properly considered in theoretical approaches. In this study, the contact behaviour of inflatable steel-tube rock bolts was investigated through a novel modelling based on the contact theory. A validating representative model test for an inflatable steel-tube rock bolts was performed and successfully reproduced through the contract modelling method. It is revealed that the contact behaviour was found to significantly differ from the theoretical assumptions. Parametric analyses were carried out to investigate the effect of influencing factors such as the diameter ratio, the elastic modulus and maximum installation pressure that cannot be considered in the theoretical model. It was found that the state of full inflation is the stress turning point where the general tube behaviour changes from mainly plastic to elastic. The maximum contact stress was obtained immediately before full inflation.","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135859778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Obituary: A tribute to Michele Jamiolkowski (1932–2023)","authors":"Renato Lancellotta","doi":"10.1680/jgeot.23.00001","DOIUrl":"https://doi.org/10.1680/jgeot.23.00001","url":null,"abstract":"","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136307977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Paul J. Vardanega, Stuart K. Haigh, Brendan C. O'Kelly, Xianwei Zhang, Xinyu Liu, Cheng Chen, Gang Wang
{"title":"Use of fall-cone flow index for soil classification: a new plasticity chart","authors":"Paul J. Vardanega, Stuart K. Haigh, Brendan C. O'Kelly, Xianwei Zhang, Xinyu Liu, Cheng Chen, Gang Wang","doi":"10.1680/jgeot.21.00268","DOIUrl":"https://doi.org/10.1680/jgeot.21.00268","url":null,"abstract":"","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135845699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The problem of cavity expansion from zero radius has no characteristic length and therefore possesses a similarity solution, in which the cavity pressure remains constant and the continuing deformation is geometrically self-similar. In this case, the incremental velocity approach first used by R. Hill in 1950 to analyse cavity expansion in Tresca materials can be extended to derive a solution for the limiting pressure of cavity expansion in other types of material. In this paper, a rigorous semi-analytical solution is derived, following Hill's incremental velocity method, for the expansion of cavities from zero initial radius in cohesive-frictional soils with limited dilation. In particular, the radius of the elastic–plastic interface c is used in this paper as the timescale and the solution for the limit pressure has been presented. Solutions are evaluated for a number of cases representative of a range of cohesive-frictional and dilatant soils. A comparison is also made between the solutions presented here and previous solutions for cohesive-frictional soils that have unlimited (on-going) plastic dilation. In particular, the influence of limited plastic dilation on the cavity limit pressure is identified and discussed.
{"title":"Cavity expansion in cohesive-frictional soils with limited dilation","authors":"John P. Carter, Hai-Sui Yu","doi":"10.1680/jgeot.21.00141","DOIUrl":"https://doi.org/10.1680/jgeot.21.00141","url":null,"abstract":"The problem of cavity expansion from zero radius has no characteristic length and therefore possesses a similarity solution, in which the cavity pressure remains constant and the continuing deformation is geometrically self-similar. In this case, the incremental velocity approach first used by R. Hill in 1950 to analyse cavity expansion in Tresca materials can be extended to derive a solution for the limiting pressure of cavity expansion in other types of material. In this paper, a rigorous semi-analytical solution is derived, following Hill's incremental velocity method, for the expansion of cavities from zero initial radius in cohesive-frictional soils with limited dilation. In particular, the radius of the elastic–plastic interface c is used in this paper as the timescale and the solution for the limit pressure has been presented. Solutions are evaluated for a number of cases representative of a range of cohesive-frictional and dilatant soils. A comparison is also made between the solutions presented here and previous solutions for cohesive-frictional soils that have unlimited (on-going) plastic dilation. In particular, the influence of limited plastic dilation on the cavity limit pressure is identified and discussed.","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135845858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Serge Leroueil, David W. Hight, Jacques Locat, Simona Guglielmi, Federica Cotecchia, Francesco Cafaro, Antonio Gens
{"title":"Analysis of the micro to macro response of clays to compression","authors":"Serge Leroueil, David W. Hight, Jacques Locat, Simona Guglielmi, Federica Cotecchia, Francesco Cafaro, Antonio Gens","doi":"10.1680/jgeot.22.d.006","DOIUrl":"https://doi.org/10.1680/jgeot.22.d.006","url":null,"abstract":"","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136265507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A novel elasto-viscoplastic formulation for compression behaviour of clays","authors":"Yixing Yuan, Andrew J. Whittle, Evert J. den Haan","doi":"10.1680/jgeot.20.d.014","DOIUrl":"https://doi.org/10.1680/jgeot.20.d.014","url":null,"abstract":"","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136019486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Surface wave methods have been developed as a commonly used non-invasive tool for shear-wave velocity (Vs) profiling of near-surface soil and rock formations. Inversion is a key step to back-calcul...
{"title":"Direct estimation of shear-wave velocity profiles from surface wave investigation of geotechnical sites","authors":"Shibin Lin, J. Ashlock, Bo Li","doi":"10.1680/JGEOT.20.P.258","DOIUrl":"https://doi.org/10.1680/JGEOT.20.P.258","url":null,"abstract":"Surface wave methods have been developed as a commonly used non-invasive tool for shear-wave velocity (Vs) profiling of near-surface soil and rock formations. Inversion is a key step to back-calcul...","PeriodicalId":55098,"journal":{"name":"Geotechnique","volume":null,"pages":null},"PeriodicalIF":5.8,"publicationDate":"2021-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41456854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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