Geomechanics for Energy and the Environment最新文献

{"title":"Differential assessment of effects of increasing model complexity in THM coupled models of the FE experiment at Mt. Terri","authors":"Sonja Kaiser ,&nbsp;Wenqing Wang ,&nbsp;Jörg Buchwald ,&nbsp;Dmitri Naumov ,&nbsp;Aqeel Afzal Chaudhry ,&nbsp;Thomas Nagel","doi":"10.1016/j.gete.2025.100637","DOIUrl":"10.1016/j.gete.2025.100637","url":null,"abstract":"<div><div>The Full-scale Emplacement (FE) experiment is studied numerically using large 3D meshes with over one million elements and degrees of freedom. Non-isothermal Richards flow coupled with mechanics is the applied physical process model. Systematic model variations are performed to generate results for a systematic comparison to a large set of measurement data utilising statistical methods. These variations are based on several hypotheses concerning potential sources of uncertainty or mismatch between modelled and measured data. Among them are geometrical aspects as well as aspects of model complexity, such as including additional materials or physical processes. The geometrical aspects include the effects of varying the inner tunnel radius, changing the heater representation, examining the uncertainty of the sensor locations and investigating geometrical aspects of adding a shotcrete layer. Complexity is increased by including shotcrete and a simplified excavation damaged zone (EDZ) as additional materials, by accounting for a ventilation phase and by providing an excavation-induced non-homogeneous initial liquid pressure field. We discuss the nature and magnitude of the effects of each of these aspects as well as their combinations. Notably, we find a large influence of the geometrical aspects on the temperature results in the tunnel on the one hand and on the other the importance of the initial liquid pressure field in the Opalinus clay. Overall, the comparison to the measurement data can be improved by incorporating the investigated aspects into models of the FE experiment.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"42 ","pages":"Article 100637"},"PeriodicalIF":3.3,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation study of proppant transport within fractures under the influence of interlayers and weak planes","authors":"Dan Zhang ,&nbsp;Liangping Yi ,&nbsp;Zhaozhong Yang ,&nbsp;Jiangang He ,&nbsp;Jingyi Zhu ,&nbsp;Xiaogang Li ,&nbsp;Hongqiang Zhang","doi":"10.1016/j.gete.2025.100642","DOIUrl":"10.1016/j.gete.2025.100642","url":null,"abstract":"<div><div>A sophisticated three-dimensional multi-cluster fracturing model is developed using a block-based discrete element method, incorporating the spatial distribution of interlayers and weak planes. This innovative model establishes uniform metrics for evaluating the propagation of fracturing fissures in multi-cluster formations and the efficacy of proppant deployment. The model facilitates an in-depth investigation into the dynamics of proppant transport within fractures, which are influenced by the presence of interlayers and weak planes. Key findings from the analysis include a negative correlation between fracturing fluid viscosity and the extent of total fissure and proppant placement areas. Larger proppant particle sizes are associated with reduced proppant placement areas, diminished placement efficiency, and heightened settling phenomena. An approach involving stepwise proppant injection enhances structural support proximal to the wellbore, leading to expanded total fissure areas, improved proppant placement, and enhanced efficiency, thereby contributing to more effective reservoir modification. Additionally, the model identifies that the presence of interlayers and the intersections between hydraulic fractures and weak planes tend to result in narrower fracturing fissures, increasing their vulnerability to proppant blockages.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"41 ","pages":"Article 100642"},"PeriodicalIF":3.3,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Centrifuge modeling of temperature effects on the pullout capacity of jacked-in energy piles in saturated soft clay","authors":"Ismaail Ghaaowd ,&nbsp;Fernando A. Saboya, jr ,&nbsp;John S. McCartney","doi":"10.1016/j.gete.2025.100638","DOIUrl":"10.1016/j.gete.2025.100638","url":null,"abstract":"<div><div>This study focuses on predicting the impacts of a heating-cooling cycle on the pullout capacity of energy piles installed through a soft clay layer. Geotechnical centrifuge physical modeling was used to evaluate temperature, pore water pressure, volume change, and undrained shear strength profiles in clay layers surrounding energy piles heated to different maximum temperatures to understand their impacts on the pile pullout capacity. During centrifugation at 50 g, piles were jacked-in at a constant rate of penetration into a kaolinite clay layer consolidated from a slurry in a cylindrical aluminum container, heated to a target temperature after stabilization of installation effects, cooled after completion of thermal consolidation requiring up to 30 hours (1250 days in prototype scale), then pulled out at a constant rate. T-bar penetration tests were performed after the heating-cooling cycle to assess differences in clay undrained shear strength from a baseline test. The pullout capacity of an energy pile heated to 80 °C then cooled to ambient temperature was 109 % greater than the capacity in the baseline test at 23 °C, representing a substantial improvement. The average undrained shear strength measured with the T-bar at a distance of 3.5 pile diameters from the pile heated to 80 °C was 60 % greater than at 23 °C but followed the same trend as pile capacity with temperature. An empirical model for the pullout capacity was developed by combining predictions of soil temperature, thermal excess pore water pressure, thermal volumetric strain, and undrained shear strength for different maximum pile temperatures. The empirical model predictions matched well with measured pullout capacities.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"41 ","pages":"Article 100638"},"PeriodicalIF":3.3,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclic plasticity of hardened oil well cement paste: A nonlinear kinematic hardening perspective","authors":"Linlin Wang ,&nbsp;Shuo Chen ,&nbsp;Shuitao Zhang ,&nbsp;Jiyun Shen ,&nbsp;Rongwei Yang","doi":"10.1016/j.gete.2025.100641","DOIUrl":"10.1016/j.gete.2025.100641","url":null,"abstract":"<div><div>The present work focuses on the deformation of oil well cement subjected to cyclic loading. Different from the conventional models based on damage theory, the strain accumulation in this study is characterized in the framework of nonlinear kinematic hardening plasticity. The main feature of the proposed model is that a recall (nonlinear) term is introduced in the hardening rule so that the back stress hardens nonlinearly with plastic deformation. Accordingly, the back stress varies differently across the unloading and reloading paths, leading to a no-closed hysteresis loop and a ratcheting strain. The proposed model is validated through several experiments conducted on oil well cements cured at different curing temperatures and curing ages. The model results for the ratcheting straining of oil well cement under both uniaxial and triaxial compression agree well with experimental results. In particular, the proposed model well reproduces a much more pronounced residual strain during the first cycle, and a minor as well as constant accumulation rate for the subsequent cycles. For a comparison, such greater residual strain and the following smaller constant residual strain can not be characterized by the conventional damage-based models, which produces an increasing accumulation rates with the cycle numbers.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"41 ","pages":"Article 100641"},"PeriodicalIF":3.3,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143132782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An evaluation method of hydraulic fracture propagation behavior in rock containing natural fractures based on fractal dimension","authors":"Yulong Liu ,&nbsp;Yanjun Zhang ,&nbsp;Yuxiang Cheng ,&nbsp;Ziwang Yu ,&nbsp;Xuefeng Gao ,&nbsp;Lei Liu","doi":"10.1016/j.gete.2025.100640","DOIUrl":"10.1016/j.gete.2025.100640","url":null,"abstract":"<div><div>This study presents a novel method for quantifying the propagation of hydraulic fractures and their interaction with natural fractures under varying fracturing conditions. We examine the impact of approach angle, fracture aperture, borehole distance, differential stress, and injection rate on hydraulic fracture behaviour using the Particle Flow Code 2D (PFC^2D) model. The results reveal two main fracture extension modes: crossing and retained. The approach angle significantly affects the fractal dimension of hydraulic fractures, with peak values of 1.12 at intermediate angles (30°–60°) and lower values (0.96–0.98) at extreme angles (0° and 90°). Increasing fracture aperture accelerates propagation by 13.7 %, while a higher injection rate raises the fractal dimension by 22.6 %. Borehole distance introduces variability, and as differential stress increases, the fractal dimension increases from 0.98 to 1.17, accompanied by a 43.4 % increase in breakdown pressure. To model temporal variations in fractal dimensions, The Logistic method adjusts the fractal dimension amplitude with parameter <span><math><msub><mrow><mi>A</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and controls the growth rate during the acceleration phase with <span><math><msub><mrow><mi>p</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>. The BiDoseResp method, by contrast, modulates amplitude using <span><math><msub><mrow><mi>A</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>A</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span>, and regulates the entry and exit stages through <span><math><msub><mrow><mi>LoGt</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>LoGt</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>. Parameters <span><math><msub><mrow><mi>h</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>, <span><math><msub><mrow><mi>h</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, and <span><math><msub><mrow><mi>p</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> govern amplitude and growth during the retention and acceleration phases. These models provide a framework for optimising hydraulic fracturing in geothermal development, enhancing fracture dynamics understanding and improving resource extraction efficiency.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"41 ","pages":"Article 100640"},"PeriodicalIF":3.3,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of coupled processes in full-scale engineered barrier system performance experiment at Horonobe Underground Research Laboratory, Japan","authors":"Hirokazu Ohno ,&nbsp;Yusuke Takayama","doi":"10.1016/j.gete.2025.100636","DOIUrl":"10.1016/j.gete.2025.100636","url":null,"abstract":"<div><div>In the geological disposal of high-level radioactive waste, the overpack lifetime and initial conditions of radionuclide migration are essential considerations along with the assessments of the environmental conditions, including study of the evolution of near-field thermal, hydrological, mechanical, and chemical processes following the emplacement of an engineered barrier system. In this study, experimental data from an in situ full-scale engineered barrier experiment at Horonobe Underground Research Laboratory were used to assess the applicability of a simulation model to evaluate near-field coupled processes. Simulation results indicate that the thermal and hydraulic properties generally explain the temperature and saturation distributions and that it is crucial to capture changes in pore water characteristics as an indicator of changes in saturation. The application of the simplified unsaturated elastoplastic constitutive model improves the reproducibility of the swelling deformation behavior of buffer materials.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"41 ","pages":"Article 100636"},"PeriodicalIF":3.3,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The impact of heat exchanger loop configuration on heat transfer in energy piles","authors":"Mohammed Faizal ,&nbsp;Abdelmalek Bouazza ,&nbsp;John S. McCartney","doi":"10.1016/j.gete.2025.100639","DOIUrl":"10.1016/j.gete.2025.100639","url":null,"abstract":"<div><div>This paper examines the impact of parallel and series U-loop configurations on heat transfer in energy piles. Heating experiments were conducted on a set of four field-scale energy piles installed under a five-storey building, sharing identical dimensions (diameter = 0.9 m and length = 15 m) but varying numbers of U-loops (loops 1, 2, 3, and 4, in Piles 1, 2, 3, and 4, respectively). The investigation highlights the significance of fluid flow, temperature, U-loop quantity and configuration on heat transfer within solitary and grouped energy piles. In the parallel configuration, heat exchange occurs concurrently across all U-loops, proportional to the flow rate. Conversely, in the series configuration, the initial U-loops dominate heat exchange, with subsequent U-loops showing diminished effectiveness in contributing to the overall heat transfer. For identical flow rates in the individual U-loops of both configurations, the group of energy piles employing parallel U-loops exhibited higher heat exchange. The findings provide practical insights into optimising U-loop configurations to improve heat exchange between the pile and the surrounding soil under the studied boundary conditions.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"41 ","pages":"Article 100639"},"PeriodicalIF":3.3,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An international study on THM modelling of the full-scale heater experiment at Mont Terri laboratory","authors":"Bastian Johannes Graupner ,&nbsp;Kate Thatcher ,&nbsp;Larissa Friedenberg ,&nbsp;Ruiping Guo ,&nbsp;Teklu Hadgu ,&nbsp;Wenbo Hou ,&nbsp;Sonja Kaiser ,&nbsp;Taehyun Kim ,&nbsp;Chan-Hee Park ,&nbsp;Changsoo Lee ,&nbsp;Edward Matteo ,&nbsp;Thomas Nagel ,&nbsp;Rebecca Newson ,&nbsp;Peng-Zhi Pan ,&nbsp;Michael Pitz ,&nbsp;Jonny Rutqvist ,&nbsp;Jan Thiedau ,&nbsp;Luca Urpi","doi":"10.1016/j.gete.2024.100631","DOIUrl":"10.1016/j.gete.2024.100631","url":null,"abstract":"<div><div>We present results from an international model comparison study of the Full-Scale Emplacement (FE) experiment in Opalinus Clay at the Mont Terri Laboratory, Switzerland. Based on a provided parameter set the teams decided which parameters they adopted for their models, whether they considered the excavation and the ventilation phase in addition to the heating phase and if they included technical features like the shotcrete or the EDZ. The teams were able to reproduce the measured parameters temperature, relative humidity and pore pressure. The modelled results for temperature agree very closely between the teams especially in the sensors in Opalinus Clay. All teams were able to reproduce the redistribution of water in the bentonite backfill due to heating. The evolution of the relative humidity showed similar trends with differences in the intensity of the dry out effect. To model the pore pressure evolution is more complex because it comprises the full interaction of the coupled THM processes. The spread between the pore pressure modelled by the teams was larger, with some teams overestimating the pressure increase due to heating and some teams overestimating the extent of drainage. The agreement of modelled results with measurements improves with larger distance to the heater. We conclude that the EDZ and the shotcrete potentially influence the behaviour of the rock causing higher differences closer to the heater. Further research is needed to better implement those influences into the models. Based on the calibrated models, the future evolution of temperature, relative humidity and pore pressure was predicted over the next 10 years following a change of the heat power applied in 2023 and 2024. Again, the predicted temperatures agree very closely between the teams. Most teams do not expect an increase in relative humidity during the next 10 years after the initial dry-out.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"41 ","pages":"Article 100631"},"PeriodicalIF":3.3,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143133428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The free-energy density function and its complementary forms for porous media saturated by two non-miscible fluids under non isothermal conditions","authors":"A. Gajo","doi":"10.1016/j.gete.2024.100624","DOIUrl":"10.1016/j.gete.2024.100624","url":null,"abstract":"<div><div>This paper presents a general method for defining the macroscopic free-energy density function and its complementary forms for a porous medium saturated by two non-miscible fluids, in the case of compressible fluid and solid constituents, non-isothermal conditions and negligible interfacial surface energy.</div><div>The major advantage of the proposed approach is that no limitation or simplification is posed on the choice of the free energies of the fluid constituents. As a result, a fully non-linear equation of state for the pore fluids can be incorporated within the proposed framework.</div><div>The method is presented under the assumption that interfacial surface energy terms are negligible, thus recovering a Bishop parameter <span><math><mi>χ</mi></math></span> coinciding with the degree of saturation, which is expected to be applicable mostly to non-plastic soils. Moreover, small strains of the solid skeleton are assumed, but the method can be easily extended to a large strain formulation as discussed below. The paper analyzes also some particular cases concerning the incompressibility of all constituents, the geometric linearization and the incompressibility only of the solid constituent.</div><div>The knowledge of the free energy density function is the starting point for the evaluation of the dissipation function, of energy and entropy balance and, in general, for the formulation of thermodynamically consistent constitutive models.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"41 ","pages":"Article 100624"},"PeriodicalIF":3.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143132793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on seepage–corrosion coupling characteristics of a single fracture in limestone subjected to acid mine drainage","authors":"Jing Liu ,&nbsp;Shuangying Zuo ,&nbsp;Yunchuan Mo","doi":"10.1016/j.gete.2024.100633","DOIUrl":"10.1016/j.gete.2024.100633","url":null,"abstract":"<div><div>To investigate the influences of the acid mine drainage (AMD) in a closed coal mine on the corrosion and seepage stability of limestone with rough fractures, both distilled water and AMD solution were employed to implement seepage-corrosion tests on the seven sets of a single fracture of limestone specimens under different hydraulic conditions. We investigated the effects of confining stress and solution on the seepage parameters. Also, the mechanism of seepage reduction of fractured limestone caused by AMD solution was proposed. Moreover, COMSOL numerical software was used to simulate the chemical-seepage coupling field characteristics of a rough fracture under condition 4. The results are as follows: (1) The permeability, the Ca²⁺ concentration gradually decreases, and the osmotic stress, the total iron concentration gradually increases during the seepage process. (2) Differences between the bedding and matrix corrosion exist, the roughness of the fracture surface decreases, and “passivation” occurs on the surface, which makes the permeability decrease rapidly in the early stages and stabilize later. (3) The real-time permeability of fractured limestone under high confining stress is smaller than that under low confining stress and the sensitivity of permeability decreased with the increase of confining stress. (4) The numerical simulated results show the diffusion area of the solution on the fracture wall expands with increasing seepage-corrosion time and osmotic stress of the entrance section. This work will be of great significance to guide the treatment of AMD and the stability analysis of engineering rock masses.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"41 ","pages":"Article 100633"},"PeriodicalIF":3.3,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143132792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}