检索结果-南通市图书馆

Numerical analysis of anisotropic stiffness and strength for geomaterials

Journal of rock Mechanics and Geotechnical Engineering 2023年第2期15卷 323-338页

作者： Fei Song Manuel A.González-Fernández Alfonso rodriguez-Dono leandro r.alejano Department of Civil and Environmental Engineering Universitat Politècnica de Catalunya(UPC)Barcelona08034Spain CINTECX GESSMin GroupDepartment of Natural Resources and Environmental EngineeringUniversity of VigoVigo36310Spain International Centre for Numerical Methods in Engineering(CIMNE) Barcelona08034Spain

In numerical modelling,selection of the constitutive model is a critical factor in predicting the actual response of a geomaterial.The use of oversimplified or inadequate models may not be sufficient to reproduce the actual geomaterial behaviour.That selection is especially relevant in the case of aniso-tropic rocks,and particularly for shales and slates,whose behaviour may be affected,e.***.well stability in geothermal or oil and gas production operations.In this paper,an alternative anisotropic constitutive model has been implemented in the finite element method software CODE_BrIGHT,which is able to account for the anisotropy of shales and slates in terms of both deformability and strength.For this purpose,a transversely isotropic version of the generalised Hooke’s law is adopted to represent the stiffness anisotropy,while a nonuniform scaling of the stress tensor is introduced in the plastic model to represent the strength anisotropy.Furthermore,a detailed approach has been proposed to determine the model parameters based on the stressestrain results of laboratory tests.Moreover,numerical analyses are performed to model uniaxial and triaxial tests on Vaca Muerta shale,Bossier shale and slate from the northwest of Spain(NW Spain slate).The experimental data have been recovered from the literature in the case of the shale and,in the case of the slate,performed by the authors in terms of stress-strain curves and strengths.A good agreement can be generally observed between numerical and experi-mental results,hence showing the potential applicability of the approach to actual case studies.Therefore,the presented constitutive model may be a promising approach for analysing the anisotropic behaviour of rocks and its impact on well stability or other relevant geomechanical problems in aniso-tropic rocks.

关键词： rock mechanics Anisotropy Numerical modelling CODE_BrIGHT Shale Slate

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Validity of continuous-failure-state unloading triaxial tests as a means to estimate the residual strength of rocks

引用

Journal of rock Mechanics and Geotechnical Engineering 2021年第4期13卷 717-726页

作者： Gabriel Walton Steven Gaines leandro r.alejano Department of Geology and Engineering Geology Colorado School of MinesGoldenCO80401USA Natural resources Canada CanmetMININGOttawaOntarioK1A 1M1Canada Department of Natural resources and Environmental Engineering Universidad de VigoVigo36310Spain

The residual strength of rocks and rock masses is an important parameter to be constrained for analysis and design purposes in many rock engineering applications.A residual strength envelope in principal stress space is typically developed using residual strength data obtained from compression tests on many different specimens of the same rock type.In this study,we examined the potential for use of the continuous-failure-state testing concept as a means to constrain the residual strength envelope using a limited number of specimens.Specifically,cylindrical specimens of three rock types(granodiorite,diabase,and Stanstead granite)were unloaded at the residual state such that a full residual strength envelope for each individual specimen was obtained.Using a residual strength model that introduces a single new strength parameter(the residual strength index,or rSI),the results of the continuous-failurestate unloading tests were compared to conventionally obtained residual strength envelopes.Overall,the continuous-failure-state residual strength data were found to be consistent with the conventional residual strength data.However,it was identified that the primary factor limiting an accurate characterization of the residual strength for a given rock type is not the amount of data for a given specimen,but the variety of specimens available to characterize the inherent variability of the rock unit of interest.Accordingly,the use of continuous-failure-state testing for estimation of the residual strength of a rock unit is only recommended when the number of specimens available for testing is very limited(i.e.<5).

关键词： residual strength Continuous-failure-state testing Compression testing Brittle rock mechanics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Particle flow code simulation of intact and fissured granitic rock samples

引用

Journal of rock Mechanics and Geotechnical Engineering 2020年第5期12卷 960-974页

作者： Uxía Castro-Filgueira leandro r.alejano Diego Mas Ivars Department of Natural resources and Environmental Engineering University of VigoVigoSpain Department of Geology and Geological Engineering Colorado School of MinesGoldenCOUSA Swedish Nuclear Fuel and Waste Management Company(SKB) StockholmSweden Division of Soil and rock Mechanics Royal Institute of Technology(KTH)StockholmSweden

This study presents a calibration process of three-dimensional particle flow code(PFC3D)simulation of intact and fissured granite samples.First,laboratory stressestrain response from triaxial testing of intact and fissured granite samples is recalled.Then,PFC3D is introduced,with focus on the bonded particle models(BPM).After that,we present previous studies where intact rock is simulated by means of flatjoint approaches,and how improved accuracy was gained with the help of parametric studies.Then,models of the pre-fissured rock specimens were generated,including modeled fissures in the form of“smooth joint”type contacts.Finally,triaxial testing simulations of 1 t 2 and 2 t 3 jointed rock specimens were performed.results show that both elastic behavior and the peak strength levels are closely matched,without any additional fine tuning of micro-mechanical parameters.Concerning the postfailure behavior,models reproduce the trends of decreasing dilation with increasing confinement and plasticity.However,the dilation values simulated are larger than those observed in practice.This is attributed to the difficulty in modeling some phenomena of fissured rock behaviors,such as rock piece corner crushing with dust production and interactions between newly formed shear bands or axial splitting cracks with pre-existing joints.

关键词： Numerical methods Artificially fissured samples rock mass behavior Particle flow code Parallel bond Flat-joint Smooth-joint

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Size effects on the tensile strength and fracture toughness of granitic rock in different tests

引用

Journal of rock Mechanics and Geotechnical Engineering 2023年第9期15卷 2179-2192页

作者： Ignacio Pérez-rey Andrea Muñoz-Ibáñez Manuel A.González-Fernández Mauro Muñiz-Menéndez Miguel Herbón Penabad Xian Estévez-Ventosa Jordi Delgado leandro ralejano Laboratorio de Geotecnia CEDEXMadridSpain CINTECX GESSMin GroupDepartment of Natural Resources and Environmental EngineeringUniversidade de VigoVigoSpain School of Civil Engineering Universidade da CoruñaA CoruñaSpain

This study investigates the tensile failure mechanisms in granitic rock samples at different scales by means of different types of tests.To do that,we have selected a granitic rock type and obtained samples of different sizes with the diameter ranging from 30 mm to 84 mm.The samples have been subjected to direct tensile strength(DTS)tests,indirect Brazilian tensile strength(BTS)tests and to two fracture toughness testing approaches.Whereas DTS and fracture toughness were found to consistently grow with sample size,this trend was not clearly identified for BTS,where after an initial grow,a plateau of results was observed.This is a rather complete database of tensile related properties of a single rock type.Even if similar databases are rare,the obtained trends are generally consistent with previous scatter and partial experimental programs.However,different observations apply to different types of rocks and experimental approaches.The differences in variability and mean values of the measured parameters at different scales are critically analysed based on the heterogeneity,granular structure and fracture mechanics approaches.Some potential relations between parameters are revised and an indication is given on potential sample sizes for obtaining reliable results.Extending this database with different types of rocks is thought to be convenient to advance towards a better understanding of the tensile strength of rock materials.

关键词： Size effect Tensile strength Fracture toughness Granite Finite fracture mechanics

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Verification of a laboratory-based dilation model for in situ conditions using continuum models

引用

Journal of rock Mechanics and Geotechnical Engineering 2014年第6期6卷 522-534页

作者： G.Walton M.S.Diederichs L.r.alejano J.Arzúa Queen's University Kingston Canada University of Vigo Vigo Spain

With respect to constitutive models for continuum modeling applications, the post-yield domain remainsthe area of greatest uncertainty. recent studies based on laboratory testing have led to thedevelopment of a number of models for brittle rock dilation, which account for both the plastic shearstrain and confining stress dependencies of this phenomenon. Although these models are useful inproviding an improved understanding of how dilatancy evolves during a compression test, there hasbeen relatively little work performed examining their validity for modeling brittle rock yield in situ. Inthis study, different constitutive models for rock dilation are reviewed and then tested, in the context of anumber of case studies, using a continuum finite-difference approach （FLAC）. The uncertainty associatedwith the modeling of brittle fracture localization is addressed, and the overall ability of mobilizeddilation models to replicate in situ deformation measurements and yield patterns is evaluated. 2014 Institute of rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

关键词： Dilation Continuum models Case studies Brittle rock

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Ground reaction curves for circular excavations in non-homogeneous,axisymmetric strain-softening rock masses

引用

Journal of rock Mechanics and Geotechnical Engineering 2013年第6期5卷 431-442页

作者： J.González-Cao F.Varas F.G.Bastante L.r.alejano Department of Natural resources and Environmental Engineering School of MinesUniversity of Vigo Department of Applied Mathematics University of Vigo

Fast methods to solve the unloading problem of a cylindrical cavity or tunnel excavated in elasto-perfectly plastic, elasto-brittle or strain-softening materials under a hydrostatic stress feld can be derived based on the self-similarity of the solution. As a consequence, they only apply when the rock mass is homogeneous and so exclude many cases of practical interest. We describe a robust and fast numerical technique that solves the tunnel unloading problem and estimates the ground reaction curve for a cylindrical cavity excavated in a rock mass with properties depending on the radial coordinate, where the solution is no longer self-similar. The solution is based on a continuation-like approach(associated with the unloading and with the incremental formulation of the elasto-plastic behavior), fnite element spatial discretization and a combination of explicit sub-stepping schemes and implicit techniques to integrate the constitutive law, so as to tackle the diffculties associated with both strong strain-softening and elasto-brittle behaviors. The developed algorithm is used for two practical ground reaction curve computation applications. The frst application refers to a tunnel surrounded by an aureole of material damaged by blasting and the second to a tunnel surrounded by a ring-like zone of reinforced(rock-bolted) material.

关键词： Tunnel convergence Ground reaction curves Strain-softening rock masses Tunnel with an aureole of a different material

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Corrigendum to “Verification of a laboratory-based dilation model for in situ conditions using continuum models” [J rock Mech Geotech Eng6 (2014) 522e534]

引用

Journal of rock Mechanics and Geotechnical Engineering 2017年第2期9卷 382-382页

作者： G. Walton M.S. Diederichs L.r. alejano J. Arzúa Queen’s University KingstonCanada University of Vigo VigoSpain

The authors regret that the photographic image in Fig. 4a of the published article was used in error, and therefore without proper referencing or permission from the originator or copyright holder. The image used in Fig. 4a of the original manuscript has been previously published by and remains under copyright by the Society for Mining, Metallurgy, and Exploration, Inc. (SME) associated with the following paper.Moalli S, redmond S, Brox D, Procter P, Jezek D, van der Pouw Kraan M, Blanchet r, Kulka r. TBM Tunneling at the Ashlu Hydro Power Project, Squamish, BC. In: Almeraris G, Mariucci B. editors. Proceedings of rapid Excavation and Tunnelling 2009. The Society for Mining,Metallurgy, and Exploration, Inc. (SME). 2009. pp. 1208e1217.To correct this error though this Corrigendum, Fig. 4 in this article is replaced with the following set of images. The caption remains unchanged from the original but is included here for convenience and clarity.

关键词： regret photographic manuscript

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：