Lang Liu , Marcin Ireneusz Duda , Antonio F. Salazar Vásquez , Andreas Nicolas Berntsen
{"title":"A review of fiber optic sensing in geomechanical applications at laboratory and field scales","authors":"Lang Liu , Marcin Ireneusz Duda , Antonio F. Salazar Vásquez , Andreas Nicolas Berntsen","doi":"10.1016/j.gete.2025.100699","DOIUrl":"10.1016/j.gete.2025.100699","url":null,"abstract":"<div><div>Geomechanical characterization and monitoring are essential for subsurface projects, including underground mining, geo-energy production, groundwater management, and geological storages of CO2 and radioactive waste. Traditional measurement techniques often face challenges such as limited spatial coverage and high operational costs. Fiber optic sensing (FOS) offers a promising alternative due to its scalability, durability, and high spatial resolution, making it particularly suitable for harsh environments and large-scale applications. This paper provides a comprehensive and critical review of the use of FOS in geomechanics, covering the principles of quasi- and fully distributed sensing and focusing on strain measurement in both laboratory and field settings. We discuss various techniques for fiber cable installation and explore the integration of FOS with other geomechanical monitoring techniques. Based on the challenges identified in the reviewed studies, we conclude that there is a need for improved fiber coupling and measurement corrections, efficient fiber cable installation, robust data handling and interpretation, and standardization across different geomechanical applications.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100699"},"PeriodicalIF":3.3,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306720","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":"Investigation of fracture propagation dynamics during multi-stage water injection shearing in fault-fracture reservoirs","authors":"Shichuan Zhang , Shilong Song , Buchu Zhang , Baotang Shen","doi":"10.1016/j.gete.2025.100700","DOIUrl":"10.1016/j.gete.2025.100700","url":null,"abstract":"<div><div>Activation of water injection-induced shear in hot dry rock reservoirs (commonly termed 'hydro-shearing') is a critical technique for enhancing permeability in enhanced geothermal systems, thereby significantly improving the efficiency of reservoir heat extraction. In this study, granite samples from geothermal reservoirs were utilized to fabricate filled jointed granite specimens, and the mechanical properties of water injection-induced shear in granite at various joint angles were examined. The experiments were conducted using a coupled mechanical-hydraulic shear testing system. Additionally, the FRACOD software was employed to simulate the evolution of key shear-enhancing fractures, including wellbore fracturing, joint penetration, and fault activation, in geothermal reservoir formations at different depths. The analysis focused on fracture development patterns, displacement fields, and stress fields at three different depth stages. By integrating a case study from the Yangbajing geothermal project in Tibet, this research investigated the effects of wellbore placement on stress fields, displacement fields, and acoustic emission energy in fracture-type thermal reservoirs. Based on the wellbore model at the 24-meter depth, a systematic sensitivity analysis was conducted to investigate the influence of four critical parameters, namely injection pressure, in-situ stress ratio, fault cohesion, and fault friction angle, on fault slip displacement. The findings indicate that the peak shear strength reduction of granite with different fracture dip angles under water pressure varies, with the 30-degree dip angle granite showing the greatest reduction due to its proximity to the shear failure angle. As burial depth increases, fracture propagation during borehole hydraulic fracturing, natural fracture activation, and fault shear stimulation becomes progressively restricted. Moreover, the wellbore placement significantly affects the response of fracture-type reservoirs, and direct injection into the fault yields superior shear stimulation effects. Injection pressure shows a strong positive correlation with fault slip, as does in-situ stress ratio, while fault cohesion and internal friction angle exhibit negative correlations. Notably, injection pressure emerges as the key factor, contributing 53.73 % to slip displacement variance. These findings provide essential insights for optimizing reservoir and wellbore construction in water-injected shear stimulation projects for hot dry rock geothermal exploitation.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100700"},"PeriodicalIF":3.3,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523011","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}
Heber Fabbri , Michael A. Maedo , Pedro Cleto , Osvaldo L. Manzoli , Marcelo Sánchez
{"title":"Coupled thermo-hydro-mechanical modeling of fracture interactions in enhanced geothermal systems","authors":"Heber Fabbri , Michael A. Maedo , Pedro Cleto , Osvaldo L. Manzoli , Marcelo Sánchez","doi":"10.1016/j.gete.2025.100698","DOIUrl":"10.1016/j.gete.2025.100698","url":null,"abstract":"<div><div>This paper presents the use of the mesh fragmentation technique (MFT) for modeling hydraulic stimulation and heat production in enhanced geothermal systems (EGS). This method simulates evolving hydraulic fractures induced by thermo-hydro-mechanical (THM) phenomena and their interaction with pre-existing natural fractures, forming an interconnected network for water circulation and energy production. The MFT combines high aspect ratio (HAR) elements within a standard finite element (FE), using appropriate constitutive models to describe mechanical, hydraulic, and thermal behaviors. Fracture evolution occurs naturally, governed only by local THM conditions and material properties, without needing special tracking algorithms or remeshing techniques. This approach relies on continuum mechanics and standard FE technology, employing simple models for energy dissipation, flow, and thermal transport due to enhanced porosity and permeability. Three application cases validate this technique. First, the proposed model shows excellent agreement with published thermo-hydraulic solutions, validating its implementation. Second, it effectively handles interactions between natural and hydraulic-driven fractures. Third, it models EGS operation for over 60 years under different <em>in-situ</em> stress scenarios and natural fracture densities. The results show the technique's effectiveness in modeling complex EGS scenarios and demonstrate its potential for optimizing EGS design.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100698"},"PeriodicalIF":3.3,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270086","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":"Experimental and numerical analysis of hydraulic fracture propagation in naturally fractured granite cores","authors":"Jia He , Li Zhuang , Muzi Li , Zhou Zhou","doi":"10.1016/j.gete.2025.100695","DOIUrl":"10.1016/j.gete.2025.100695","url":null,"abstract":"<div><div>Understanding hydraulic fracture (HF) propagation in naturally fractured granite reservoir is of great importance for deep geothermal energy exploitation. We first conducted laboratory hydraulic fracturing tests on granite outcrops containing natural fractures (NF) and observed deflection of HF toward the NF in a parallel-approach case, and arrested HF in a perpendicular-approach case. Then, a two-dimensional discrete element model is employed to analyze coupled hydro-mechanical processes in the experiments. Our modeling results reveal that, for a parallel-approach case, HF tends to deflect toward the NF when the normal distance between the HF propagation path and NF is less than 5 mm (equivalent to borehole diameter). HF crossing at perpendicular-approach case was found to occur only when two conditions are met: (i) the maximum principal stress at the intersection exceeds the tensile strength of rock, and (ii) no shear failure occurs in NF. Finally, we examined the combined effects of approach angle, NF friction coefficient, and differential principal stress under a constant minimum principal stress (<em>σ</em><sub><em>h</em></sub>) of 10 MPa. HF crossing occurred only when the differential principal stress (<em>σ</em><sub><em>H</em></sub> <em>- σ</em><sub><em>h</em></sub>) ≥ 3 MPa, and was further promoted by larger approach angles (e.g., <em>θ</em> > 50°) and higher NF friction coefficients (e.g., <em>μ</em> > 0.4).</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100695"},"PeriodicalIF":3.3,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261454","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 study of the effect of soil-plant-atmosphere interaction under future climate projections and different vegetation covers","authors":"Maryam Sadat Maddah Sadatieh , Aikaterini Tsiampousi , Athanasios Paschalis","doi":"10.1016/j.gete.2025.100697","DOIUrl":"10.1016/j.gete.2025.100697","url":null,"abstract":"<div><div>Soil-plant-atmosphere interaction (SPAI) plays a significant role on the safety and serviceably of geotechnical infrastructure. The mechanical and hydraulic soil behaviour varies with the soil water content and pore water pressures (PWP), which are in turn affected by vegetation and weather conditions. Focusing on the hydraulic reinforcement that extraction of water through the plant roots offers, this study couples advances in ecohydrological modelling with advances in geotechnical modelling, overcoming previous crude assumptions around the application of climatic effects on the geotechnical analysis. A methodology for incorporating realistic ecohydrological effects in the geotechnical analysis is developed and validated, and applied in the case study of a cut slope in Newbury, UK, for which field monitoring data is available, to demonstrate its successful applicability in boundary value problems. The results demonstrate the positive effect of vegetation on the infrastructure by increasing the Factor of Safety. Finally, the effect of climate change and changes in slope vegetation cover are investigated. The analysis results demonstrate that slope behaviour depends on complex interactions between the climate and the soil hydraulic properties and cannot be solely anticipated based on climate data, but suctions and changes in suction need necessarily to be considered.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100697"},"PeriodicalIF":3.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144270087","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}
Zhengjie Liu , Yongdong Jiang , Shizhe Song , Hongtao Zhang , Fuxin Guo
{"title":"Research on the brittle characteristics of shale under long-term CO2-H2O-shale coupling effects","authors":"Zhengjie Liu , Yongdong Jiang , Shizhe Song , Hongtao Zhang , Fuxin Guo","doi":"10.1016/j.gete.2025.100696","DOIUrl":"10.1016/j.gete.2025.100696","url":null,"abstract":"<div><div>Hybrid fracturing focuses on optimizing the extraction of shale gas. In order to solve the issues of shale reservoir fracturing and CO<sub>2</sub> storage stability. Research was conducted to examine the mechanical properties of shale under long-term CO<sub>2</sub>-H<sub>2</sub>O-shale coupling effects. The results reveal that the SC-CO<sub>2</sub>-H<sub>2</sub>O-shale coupling effects increase shale porosity and pore size due to the dissolution of minerals. Concurrently, Shale cohesion and internal friction angle decrease. Following prolonged SC-CO<sub>2</sub>-H<sub>2</sub>O-shale coupling effects, there is a decline in shale strength and elastic modulus decline, alongside a decrease in axial strain (such as the growth of the compaction segment, but the shortening of the elastic and strain hardening segments). lateral strain increase, resulting in a higher Poisson's ratio. Additionally, the indices BI<sub>1</sub> rises by 47.44 %, whereas BI<sub>2</sub> drops by 66.85 %, improving the shale's drillability and cuttability. the indices BI<sub>3</sub>, BI<sub>4</sub>, BI<sub>5</sub>, and BI<sub>6</sub> increase by 11.90 %, 45.10 %, 15.19 %, and 8.99 %, respectively, highlighting the shale's brittle characteristics. However, the indices BI<sub>7</sub>, BI<sub>8</sub>, and BI<sub>9</sub> decrease by 35.05 %, 38.20 %, and 46.67 %, indicating a reduction in the shale's fracturability. Confining pressure reduces lateral strain and increases axial strain, result in an increase in shale Poisson's ratio and strength. Following enhanced confining pressure, the indices BI<sub>3</sub> drops by 1.19–10.61 %, BI<sub>4</sub> decreases by 43.14–61.29 %, BI<sub>5</sub> falls by 1.27–14.29 %, and BI<sub>6</sub> declines by 1.12–8.42 %. Consequently, the failure characteristics transition from brittle to plastic. The SC-CO<sub>2</sub>-H<sub>2</sub>O-shale coupling effects facilitate the growth of fractures in unfractured areas. However, the elevated ground stress and reduced fracturability of the shale reservoirs restricts the growth of fractures in fractured zone, ensuring the stability of CO<sub>2</sub> storage.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100696"},"PeriodicalIF":3.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241042","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":"Experimental study of the time-dependent behaviour of fracture propagation in salt rock","authors":"Andreu Escanellas , Eduardo Cámara , Joaquín Liaudat , Ignacio Carol","doi":"10.1016/j.gete.2025.100687","DOIUrl":"10.1016/j.gete.2025.100687","url":null,"abstract":"<div><div>This paper presents an experimental study investigating the time-dependent behaviour of fracture propagation in salt rock. The research is aimed at enhancing the understanding of the fracture mechanics of salt rock, which is crucial for applications such as underground storage of hazardous waste and energy storage. Thirteen Wedge Splitting Tests (WST) were performed on salt rock specimens at four different loading rates, complemented by nine uniaxial creep tests on the same material at three stress levels. The WST results revealed major effects of the loading rate on the fracturing process, with decreasing rates leading to increased mechanical work required for splitting and reduced peak splitting force. The produced experimental dataset offers an excellent benchmark for the validation of numerical models including creep and fracture of salt rock. Additionally, the paper includes preliminary finite element simulations incorporating an inviscid discrete fracture representation and linear viscoelastic creep modelling in the bulk material that provide first insights into the origin of the observed loading rate effects. The numerical study concludes that these effects are mainly due to phenomena developed in the fracture process zone. The findings emphasise the need to consider time-dependency in Cohesive Zone Models used for salt rock fracture representation.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100687"},"PeriodicalIF":3.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241043","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}
Hongying Tan , Hejuan Liu , Chunhe Yang , Haijun Mao , Yujia Song , Debin Xia , Shengnan Ban , Weimin Wang
{"title":"Energy evolution and distribution patterns of sandstone and its microscopic mechanism under multistage cyclic loading","authors":"Hongying Tan , Hejuan Liu , Chunhe Yang , Haijun Mao , Yujia Song , Debin Xia , Shengnan Ban , Weimin Wang","doi":"10.1016/j.gete.2025.100694","DOIUrl":"10.1016/j.gete.2025.100694","url":null,"abstract":"<div><div>Sandstone, as a fundamental engineering material in depleted oil and gas reservoir gas storage systems, is susceptible to damage and failure under periodic stress disturbances. In this study, multi-level multi-cyclic loading tests were carried out on sandstone samples over the confining pressures range of 5–40 MPa, accompanied by real-time acoustic emission (AE) monitoring and periodic nuclear magnetic resonance (NMR) measurements. This study investigats the effects of confining pressure, stress level, and the number of cycles on energy evolution and energy distribution in rock, revealing the micromechanisms of energy evolution during cyclic loading. The results indicate that during the first cyclic loading, the input energy is primarily converted into dissipated energy through the compression of small pores and some medium pores. In subsequent loading cycles, the input energy is primarily converted into dissipated energy through the initiation and propagation of internal microcracks. Under high confining pressure, the rock transitions from brittle to ductile behavior, enabling it to withstand greater deformation. Additionally, at high confining pressure, rocks accumulate more strain energy, while energy dissipation is higher compared to lower confining pressures. Throughout the cyclic loading, dissipated energy consistently accounts for less than 30 % of the total input energy across all stress levels. The linear energy storage coefficient remains independence from stress level and cycle number, but exhibits an inverse relationship with confining pressure. There is an obvious linear relationship between rock dissipation energy and AE energy. Higher AE energy indicate that the rock dissipates more strain energy.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"43 ","pages":"Article 100694"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144288867","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":"Internal erosion of sandy gravels and occurrence of open-framework gravels in the subsoil of a river dike","authors":"Stéphane Bonelli , Laurence Girolami","doi":"10.1016/j.gete.2025.100690","DOIUrl":"10.1016/j.gete.2025.100690","url":null,"abstract":"<div><div>When a river dike is built on a sandy gravel paleo-valley, successive floods can induce internal erosion. This is the subject of this work, with a finite element analysis of a river dike system. This type of analysis makes it possible to find artesian and uplift zones in the protected floodplain, an element to be integrated into flood hazard mapping. The study area is the River Agly in southern France, where numerous leaks, sand boils and sinkholes have been observed along the dikes. The aim is to better understand the origin of these surface signatures, as well as the cause of the presence of open-framework gravel in the subsurface. A suffusion model for sandy gravel was used to describe internal erosion. Internal erosion effectively transforms the sandy gravel into gravel, revealing open-framework gravel zones in the paleo-valley. Contact erosion in gravel can be triggered by suffusion, showing that new models coupling suffusion and contact erosion are needed to model internal erosion in sandy gravels.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"42 ","pages":"Article 100690"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195205","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}
Zhiwu Zhou , Yu jin Wang , Lorena Yepes-Bellver , Julián Alcalá , Víctor Yepes
{"title":"Intelligent monitoring of loess landslides and research on multi-factor coupling damage","authors":"Zhiwu Zhou , Yu jin Wang , Lorena Yepes-Bellver , Julián Alcalá , Víctor Yepes","doi":"10.1016/j.gete.2025.100692","DOIUrl":"10.1016/j.gete.2025.100692","url":null,"abstract":"<div><div>Landslides in the Loess Plateau region is one of the most severe geological disasters worldwide that cause fatalities and property damage, and there is an urgent need for researchers to conduct in-depth research and scientific prevention and control measures. This paper comprehensively studies the micro and energy distribution and loss changes inside the structure of loess landslide groups under multiple factor disturbances through interdisciplinary theoretical research and comprehensive management experimental monitoring of practical cases, combined with establishing a three-dimensional monitoring network system and intelligent real-time deformation monitoring. The research conclusion provides a sufficient scientific basis for determining the dynamic deformation and development trend and predicting the stability of landslides. The spatial system achievements of the research provide rich experience and theoretical results for landslide instability warning, design and construction management, and comprehensive intelligent monitoring.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"42 ","pages":"Article 100692"},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195204","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}