Geomechanics for Energy and the Environment最新文献

{"title":"Hydromechanical and geochemical behavior of a serpentinized harzburgite","authors":"Pouyan Asem ,&nbsp;Vaughan Voller ,&nbsp;Juerg Matter ,&nbsp;Joseph F. Labuz","doi":"10.1016/j.gete.2025.100727","DOIUrl":"10.1016/j.gete.2025.100727","url":null,"abstract":"<div><div>Many hydrogeological processes are influenced by fluid infiltration into low-porosity serpentinites and the corresponding coupled hydromechanical-geochemical response. The interpretation of these coupled processes requires detailed measurement of poromechanical parameters and careful water sampling and analysis. We measured the poroelastic properties that control the hydromechanical response - drained bulk modulus <em>K</em>, unjacketed bulk modulus <span><math><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>'</mo></mrow></math></span>, and Biot coefficient <em>α</em> - for a serpentinized harzburgite from the Semail ophiolite, Oman. For the Terzaghi effective mean stress of 2.0 &lt; <span><math><mrow><mi>P</mi><mo>'</mo></mrow></math></span> = <em>P</em><span><math><mrow><mo>−</mo><mi>p</mi></mrow></math></span> &lt; 7.0 MPa, the poroelastic coefficients <em>K</em> and <em>α</em> exhibit effective mean stress dependency; the ranges are 17.0 &lt; <em>K</em> &lt; 25.6 GPa and 0.74 &gt; <em>α</em> &gt; 0.60. The unjacketed bulk modulus <span><math><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>′</mo></mrow></math></span> = 64.4 GPa is measured at <span><math><mrow><mi>P</mi><mo>'</mo></mrow></math></span> = 0 MPa. These parameters are used to interpret the diffusion during pulse decay tests, showing that permeability varies with effective mean stress: 2 × 10⁻²² &gt; <em>k</em> &gt; 5 × 10⁻²² m². Water sampling and analysis of fluid composition provided data on the geochemical processes. The geochemical analyses suggest that no new carbonate and serpentine minerals formed after some 47 weeks of reaction.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100727"},"PeriodicalIF":3.7,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720800","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":"Hydro-mechanical and homogenization behaviour of GMZ bentonite pellets/block assemblies upon hydration","authors":"Zhang-Rong Liu ,&nbsp;Wei-Min Ye ,&nbsp;He-Hua Zhu ,&nbsp;Yong-Gui Chen ,&nbsp;Qiong Wang","doi":"10.1016/j.gete.2025.100726","DOIUrl":"10.1016/j.gete.2025.100726","url":null,"abstract":"<div><div>Bentonite pellets and block are jointly used to construct engineered barrier systems in geological repository. The hydro-mechanical behavior and homogenizations of bentonite pellets/block assemblies are of significant concern to the long-term operational safety of the repository. In this study, Gaomiaozi (GMZ) bentonite pellets were combined with block of different initial dry densities in three types of assemblies (I, II and III) and subjected to hydration under isochoric conditions. Evolutions of axial and lateral swelling pressures as well as local water contents and dry densities were measured. The pore structures of specimens after different durations of hydration were detected and analyzed with resort to X-ray μCT and mercury intrusion porosimetry (MIP) techniques. Results show that, the development modes and final values of axial and lateral swelling pressures were highly dependent on the assembly type and the initial dry density of the block. Affected by wall friction and fabric anisotropy, the final lateral swelling pressure on the pellets side was higher than that on the block side and the final axial swelling pressure was in between. No significant water infiltration rate difference was observed among the three assembly types, due to water availability was limited by a thin layer of bentonite gels initially formed near to the specimen bottom and the inter-pellet pores were closed gradually by the swelling pellets. For all the three assembly types, after an initial hydration stage (&gt; 72 h), the pellets zone was compressed by the swelling block zone and the pellets/block interface tended to bend/move towards the pellets side, leading to a rearrangement of pellets, closing of the inter-pellet pores, healing of the interface and thus homogenization of the specimen. The degree of homogenization was evaluated quantitatively to decrease with increasing hydration time using a relatively porosity homogenization index (<em>RPHI</em>). However, the residual heterogeneity still remained even after full saturation, indicating the homogenization will persist for a long term.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100726"},"PeriodicalIF":3.7,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144723434","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 nucleation of injection-induced earthquakes on low-permeability strike-slip faults","authors":"David Santillán ,&nbsp;Cristina Vila ,&nbsp;Juan Carlos Mosquera ,&nbsp;Luis Cueto-Felgueroso","doi":"10.1016/j.gete.2025.100713","DOIUrl":"10.1016/j.gete.2025.100713","url":null,"abstract":"<div><div>The injection of fluids into underground formations may induce damaging earthquakes and increase the sensitivity of injection sites to remote triggering. If the fault constitutive behavior and geomechanical conditions permit the development of a frictional instability, slip may eventually accelerate and trigger a coseismic slip event. We investigate the frictional and hydromechanical mechanisms that control the slip instability preceding an induced earthquake, the nucleation phase. Understanding fault reactivation and the transition from quasi-static aseismic slip to dynamic rupture is an important objective, as the nucleation phase may provide the key to detect preseismic signals and estimate the magnitude of the resulting earthquake. Our simulations show that poroelasticity coupling delays the onset of slip and dynamic rupture and creates asymmetric slip and pressure distributions on the fault. Our results indicate that pressure-driven nucleation patterns, while qualitatively similar to those of tectonic earthquakes in elastic media, are controlled by flow processes and poroelastic couplings that favor nucleation-zone expansion. Our numerical results suggest that nucleation lengths <span><math><mi>L</mi></math></span> for induced events scale proportional to the classical scaling <span><math><mrow><msub><mrow><mi>L</mi></mrow><mrow><mi>∞</mi></mrow></msub><mo>=</mo><mfrac><mrow><mi>b</mi></mrow><mrow><msup><mrow><mrow><mo>(</mo><mi>b</mi><mo>−</mo><mi>a</mi><mo>)</mo></mrow></mrow><mrow><mn>2</mn></mrow></msup></mrow></mfrac><mfrac><mrow><msup><mrow><mi>G</mi></mrow><mrow><mo>′</mo></mrow></msup><msub><mrow><mi>D</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow><mrow><msubsup><mrow><mi>σ</mi></mrow><mrow><mi>n</mi></mrow><mrow><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></mrow></msubsup></mrow></mfrac></mrow></math></span> and time to nucleation with <span><math><msup><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>. Moreover, since <span><math><mrow><msub><mrow><mi>τ</mi></mrow><mrow><mi>n</mi><mi>u</mi><mi>c</mi></mrow></msub><mo>∼</mo><msup><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span> and <span><math><mrow><mi>L</mi><mo>∼</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>∞</mi></mrow></msub></mrow></math></span>, then <span><math><mrow><msub><mrow><mi>τ</mi></mrow><mrow><mi>n</mi><mi>u</mi><mi>c</mi></mrow></msub><mo>∼</mo><msubsup><mrow><mi>L</mi></mrow><mrow><mi>∞</mi></mrow><mrow><mn>2</mn></mrow></msubsup></mrow></math></span>. A longer nucleation phase leads to higher pore pressures and a weaker fault at the onset of dynamic rupture.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100713"},"PeriodicalIF":3.3,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695275","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":"Erosion mechanism of subsea tunnel considering non-linear seepage and linearly varying permeability coefficient with time","authors":"Xiang Liu ,&nbsp;Bangmeng Fu ,&nbsp;Kuichen Li ,&nbsp;Annan Jiang ,&nbsp;Qian Fang ,&nbsp;Jianye Li","doi":"10.1016/j.gete.2025.100722","DOIUrl":"10.1016/j.gete.2025.100722","url":null,"abstract":"<div><div>The erosion mechanism of the subsea tunnel is complicated due to the unique submarine environment. Most research assumes the fluid follows Darcy's law and neglects the increasing permeability coefficient of the grouting zone with continuous chloride ion erosion. However, the grouting and lining zones exhibit relatively high density, causing the deviation of flow seepage from Darcy's law to non-Darcy's law. This paper aims to accurately study the erosion mechanism under non-Darcy seepage condition using Hansbo's non-linear seepage model. The entire erosion process is divided into three stages: (a) initial erosion, (b) developed erosion, and (c) rapid erosion. The focus is on investigating the erosion mechanism during the developed erosion stage, in which the grouting zone follows the linear segment of Hansbo's non-linear seepage law and the lining zone follows the curved segment under relatively high-water levels. The analytical solutions for the erosion depth and ion concentration are obtained, considering the linearly varying permeability coefficient of the grouting zone over time. Our proposed method is validated through the numerical simulation and established solution. In addition, parametric analyses are conducted including the service time and change of the permeability coefficient. It reveals that the pore pressure and erosion depth at different locations of the grouting zone increase approximately linearly as the water head acting on the ground surface increases. The erosion depth and ion concentration increase with the service time, with the most significant impact observed at the tunnel invert. A greater impact on the concentration is found closer to the surface of the grouting zone. The erosion depth is deeper considering the linearly varying permeability coefficient rather than a constant. However, the influence on ion concentration is minimal.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100722"},"PeriodicalIF":3.3,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695274","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 engineering elastoplastic anisotropic model applied to the modelling of deep tunnelling in Opalinus Clay","authors":"Aldo Madaschi ,&nbsp;Julia Leuthold ,&nbsp;Linard Cantieni ,&nbsp;Silvio B. Giger ,&nbsp;Lyesse Laloui","doi":"10.1016/j.gete.2025.100721","DOIUrl":"10.1016/j.gete.2025.100721","url":null,"abstract":"<div><div>This paper introduces the Enhanced Anisotropic Damage Plasticity (eADP) model, a novel engineering constitutive approach tailored for tunnel analyses in Opalinus Clay – the designated host rock for the Swiss radioactive waste repository. The model's key innovations lie in its ability to comprehensively capture the complex behaviour of Opalinus Clay within an extremely efficient computational framework, making it suitable for routine engineering calculations and performance assessments. The eADP model adeptly reproduces Opalinus Clay's highly nonlinear stress-strain responses, accounting for anisotropic characteristics for stiffness, strength, and hardening. Honouring such complexity in material behaviour while keeping an efficient numerical performance was a key aspect of the eADP implementation. The model calibration relies on an extensive dataset derived from undrained triaxial tests performed on Opalinus Clay samples sourced recently from the Swiss candidate repository sites. The enhanced formulation and the multi-level optimisation scheme developed and applied in this work ensures a simple and robust parameter identification, showcasing the model's adaptability across varying loading conditions and confining pressures. The verification through hydromechanical computations at repository depths underscores the model's efficacy in realistic tunnel excavation scenarios.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100721"},"PeriodicalIF":3.3,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144680696","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":"Creep characteristics and damage mechanisms of rock in the plateau tunnel: Insights from acoustic emission and energy evolution","authors":"Yanzhe Li,&nbsp;Chuanxin Rong,&nbsp;Zhensen Wang,&nbsp;Yang Wang","doi":"10.1016/j.gete.2025.100720","DOIUrl":"10.1016/j.gete.2025.100720","url":null,"abstract":"<div><div>The in-situ stress in plateau tunnels is significantly high and exhibits a complex distribution. Consequently, the long-term creep behavior of deep surrounding rock poses a critical challenge to the stability and integrity of tunnel engineering in plateau mountainous areas. To address this issue, this study performs triaxial creep tests on gneissic granite samples obtained from plateau tunnels under various stress paths. Additionally, the mechanical analysis is enhanced by incorporating acoustic emission characteristics and energy evolution. Two stress paths—continuous loading and confining pressure unloading—were implemented. Key parameters, including AE count, cumulative energy, and energy competition ratio <em>R</em>, were analyzed. The results indicate that: (1) Under the confining pressure unloading path, the accelerated creep stage duration,which just occupied 1.33 % of total loading time, was significantly shorter than that under continuous loading, with a 12.3 % reduction in failure strength, suggesting lower confinement facilitates microcrack propagation and rapid instability; (2) AE parameters and energy release patterns effectively characterized creep stages: steady-state creep exhibited steady AE activity, while abrupt increased in N and ΣE mark accelerated creep, with shear-dominated failure of over 69.9 %; (3) The energy competition ratio <em>R</em> grew exponentially beyond the critical deviatoric stress, though localized energy aggregation still triggered shear failure. This study elucidates how stress paths govern energy distribution and damage evolution, providing theoretical insights for stability assessment and disaster prevention in plateau tunnel engineering.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100720"},"PeriodicalIF":3.3,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144634529","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":"Unified models for water permeability in hydrate-bearing sandy soil considering pore morphology evolution","authors":"Lin-Yong Cui ,&nbsp;Chao Zhou ,&nbsp;Sheng Dai","doi":"10.1016/j.gete.2025.100717","DOIUrl":"10.1016/j.gete.2025.100717","url":null,"abstract":"<div><div>The water permeability of hydrate-bearing sediments is of paramount importance for assessing the exploitation efficiency of methane hydrate from reservoirs. It is largely influenced by the interrelated factors of hydrate morphology and saturation. Experimental results revealed that as hydrate saturation increases, the pore morphology shifts from primarily grain-coating to predominantly pore-filling, but this coupling effect between hydrate morphology and saturation on water permeability is often overlooked in existing models. This study aims to model the water permeability of hydrate-bearing sandy soils, considering the evolution of pore morphology with changing hydrate saturation. An eccentric annulus is used to depict the pore structure of pore-filling hydrate, in contrast to the conventional unrealistic concentric annulus geometry. Two new models to describe water relative permeability were derived, each incorporating only a single parameter, assuming that grain-coating and pore-filling hydrates grow at different rates either sequentially or simultaneously. These models were validated using a dataset comprising 29 hydrate-bearing soils, with the hydrate saturations ranging from approximately 0 to 0.9. Comparison between model predictions and experimental data confirmed the good performance of both water permeability models, with low RMSE, MAE and GMV values of around 0.05, 0.03 and 1.28, respectively. Both models were further improved by correlating the two parameters with porosity data, which could ensure a rapid estimation of relative permeability based solely on porosity data without requiring any fitting parameters. Results in this study provide a novel perspective for understanding the impact of hydrate evolution on permeability reduction in hydrate-bearing soils.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100717"},"PeriodicalIF":3.3,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655434","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 modelling of energy geostructures in soil: A review","authors":"Rui Zhao ,&nbsp;Cong Shao ,&nbsp;Jonathan Adam Knappett ,&nbsp;Anthony Kwan Leung ,&nbsp;Teng Liang ,&nbsp;Liangtong Zhan ,&nbsp;Yunmin Chen","doi":"10.1016/j.gete.2025.100719","DOIUrl":"10.1016/j.gete.2025.100719","url":null,"abstract":"<div><div>Energy geostructures integrate heat exchange pipes of ground source heat pump systems within traditional underground structures, serving the dual purpose of extracting geothermal energy and supporting above-ground structures. The interaction between geothermal structures and soil involves heat transfer, pore pressure evolution and soil skeleton deformation, exhibiting a coupled thermo-hydro-mechanical response. Although detailed numerical and analytical models have been developed to analyze the thermo-hydro-mechanical behaviour of energy geostructures in soil, significant challenges remain in validating this coupled response. Centrifuge modelling provides prototype confining stresses in reduced-scale models, providing an alternative to field measurements with more controllable conditions and at lower cost. This paper reviews the current state of the art of centrifuge modelling of energy geostructure–soil interaction, with a particular focus on (i) scaling laws; (ii) evaluations of existing heating and cooling systems; (iii) soil modelling, including material selection and model preparation; and (iv) scale modelling of energy geostructural elements. Each section emphasizes the challenges of centrifuge modelling and presents identified solutions to these challenges. Finally, the prospect for future studies is discussed, highlighting the potential to enhance understanding of the underlying mechanisms controlling thermo-hydro-mechanical behaviour of geothermal structures in soil.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100719"},"PeriodicalIF":3.3,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144703677","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":"Effect of particle size on mechanical properties of bio-cemented sand using enzyme-induced calcite precipitation","authors":"Qi-Wu Jiang ,&nbsp;Ming Huang ,&nbsp;Kai Xu ,&nbsp;Ming-Juan Cui ,&nbsp;Gui-Xiao Jin ,&nbsp;Xiao-Ping Zhang","doi":"10.1016/j.gete.2025.100718","DOIUrl":"10.1016/j.gete.2025.100718","url":null,"abstract":"<div><div>Enzyme-induced carbonate precipitation (EICP) has emerged as a promising eco-friendly biotechnology for soil stabilization. The mechanical properties of bio-cemented sands are largely determined by particle size characteristics. However, the influencing mechanism of particle size characteristics on bio-cemented sands remains unclear. In this study, a series of bio-cemented sand column tests were conducted to explore particle size effects. Different particle size (coarse, medium, fine) were treated with different numbers of cycles (6, 8, 10). Multiple key parameters of the bio-cemented sands were measured, including permeability, unconfined compressive strength (<em>UCS</em>), calcium carbonate content (<em>CCC</em>), and wave velocity. The SEM imaging technique was employed to demonstrate the impact of sand particle size on cementation effect in bio-cemented specimens. Linear relationships were established between wave velocity, permeability, <em>UCS</em>, and <em>CCC</em> with different particle size. The results showed that particle size significantly influences the <em>CCC</em>, <em>UCS</em>, wave velocity, and permeability of EICP-treated sands. Medium-grained sands exhibited the highest <em>UCS</em> and wave velocity under EICP treatment. This is attributed to medium sands can achieve a good balance between the efficiency of pore-filling by calcium carbonate crystals and the infiltration of the EICP solution. Fine sands suffered from inhomogeneous CaCO₃ distribution due to the clogging of pores, which hindered the uniform penetration of the EICP solution. Coarse sands showed limited cementation owing to oversized pores, which impeded the effective interparticle bonding mediated by precipitated calcium carbonate. These findings establish particle size thresholds for EICP efficacy, providing critical guidelines for particle size selection in field-scale biocementation projects.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100718"},"PeriodicalIF":3.3,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662254","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":"Thermal influence zone of energy tunnels in sandy soils under the hydrostatic condition","authors":"Alaaeldin Magdy ,&nbsp;Alice Di Donna ,&nbsp;Hussein Mroueh","doi":"10.1016/j.gete.2025.100716","DOIUrl":"10.1016/j.gete.2025.100716","url":null,"abstract":"<div><div>Energy geostructures are more and more considered as a possible solution to cover heating and cooling needs. They function according to the principle of shallow geothermal energy, exchanging heat with the ground. This results in a zone underground where the temperature of the ground is affected by the presence of the geothermal system, which is called thermal influence zone. As the number of energy geostructures increases, determining their thermal influence zone becomes crucial, especially in environments where adjacent energy geostructures or other geothermal systems coexist. Indeed, avoid or minimize the overlap between the thermal influence zones of different geothermal installations is important to ensure their efficiency. This study investigates the effects of groundwater level, thermal operation period, and ground permeability, in both heating and cooling modes, on the thermal influence zone generated around an energy tunnel. The results indicate that the thermal induced change in groundwater density and viscosity due to geothermal operations generates groundwater circular flows. These flows play a major role in shaping the thermal influence zone. In the heating mode (winter), when the groundwater is within the vicinity of the tunnel, i.e., above, at or just below the tunnel, the thermal influence zone takes an oval shape elongated below the tunnel invert. In the cooling mode (summer), the thermal influence zone does not follow a specific shape, and it is remarkably changed by the groundwater level. For instance, when the groundwater level is shallow, the thermal influence zone extends significantly upward, potentially overlapping with the surface layer affected by atmospheric air temperature. However, when the groundwater level at the tunnel centreline, the thermal influence zone takes a horizontal oval shape, which might interfere with adjacent similar installations. The expansion of the thermal influence zone is highly dependent on the operation duration. In winter, the downward elongation after 6 months operation reaches around 1.5 times that after 3 months.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100716"},"PeriodicalIF":3.3,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670356","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}