Real‐time simulation of large‐scale geomechanics problems, such as hydraulic dilation stimulation, is computationally expensive as they must span multiple spatial and temporal length scales, often including nonlinearities and thermo‐hydromechanical processes. This paper introduces a novel local reduced order model (LROM) to enhance computational efficiency for nonlinear and fully‐coupled hydromechanical simulations. The model employs finite element analysis of a two‐dimensional deformable porous media with Drucker–Prager plasticity and stress‐induced permeability enhancement models to describe behavior of sandstone. LROM combines various reduced order models (ROMs), including proper orthogonal decomposition‐Galerkin (POD‐G) to reduce number of degrees of freedom (DoFs), discrete empirical interpolation method (DEIM) to accelerate computation of nonlinear terms, and local POD and local DEIM (LPOD/LDEIM) for further performance enhancements. LPOD and LDEIM classify parameterized training data, obtained from offline coupled full order model (CFOM) runs, into multiple subspaces with similar dynamic features. A new strategy for clustering and classification techniques that align with coupled formulation framework is proposed. The advantages of LROM are demonstrated in a large‐scale application: hydraulic dilation stimulation. LROM exhibits stable, accurate, and efficient online phase, while ROM built with classical POD/DEIM lacks efficiency and stability in Newton–Raphson solver. First, performance of LROM, parameterized by hardening modulus and initial permeability, is evaluated for inputs within training domain. Under CFOMs with DoFs, LROM speed‐up is 400 times. LROM is then parameterized by three inputs, including injection rate and two material properties. Results show that LROM maintains efficiency even for injection rates that extend beyond the training regime.
{"title":"Parameterized Local Reduced Order Model of Stimulated Volume Evolution in Reservoirs","authors":"Saeed Hatefi Ardakani, Robert Gracie","doi":"10.1002/nag.3988","DOIUrl":"https://doi.org/10.1002/nag.3988","url":null,"abstract":"Real‐time simulation of large‐scale geomechanics problems, such as hydraulic dilation stimulation, is computationally expensive as they must span multiple spatial and temporal length scales, often including nonlinearities and thermo‐hydromechanical processes. This paper introduces a novel local reduced order model (LROM) to enhance computational efficiency for nonlinear and fully‐coupled hydromechanical simulations. The model employs finite element analysis of a two‐dimensional deformable porous media with Drucker–Prager plasticity and stress‐induced permeability enhancement models to describe behavior of sandstone. LROM combines various reduced order models (ROMs), including proper orthogonal decomposition‐Galerkin (POD‐G) to reduce number of degrees of freedom (DoFs), discrete empirical interpolation method (DEIM) to accelerate computation of nonlinear terms, and local POD and local DEIM (LPOD/LDEIM) for further performance enhancements. LPOD and LDEIM classify parameterized training data, obtained from offline coupled full order model (CFOM) runs, into multiple subspaces with similar dynamic features. A new strategy for clustering and classification techniques that align with coupled formulation framework is proposed. The advantages of LROM are demonstrated in a large‐scale application: hydraulic dilation stimulation. LROM exhibits stable, accurate, and efficient online phase, while ROM built with classical POD/DEIM lacks efficiency and stability in Newton–Raphson solver. First, performance of LROM, parameterized by hardening modulus and initial permeability, is evaluated for inputs within training domain. Under CFOMs with DoFs, LROM speed‐up is 400 times. LROM is then parameterized by three inputs, including injection rate and two material properties. Results show that LROM maintains efficiency even for injection rates that extend beyond the training regime.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"33 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143862130","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}
We present a constitutive model for the mechanical behavior of granular flow for both solid‐like and fluid‐like regimes. The stress rate tensor is decomposed into rate‐independent and rate‐dependent parts. The hypoplastic model is used for the rate‐independent part, while the ‐type rheological model is employed for the rate‐dependent part. The Stokes number is introduced to capture the influence of interstitial fluid viscosity within the rate‐dependent part of the model. The model performance is demonstrated through numerical simulations of element tests, encompassing both granular materials and granular‐fluid mixtures.
{"title":"Numerical Model for Granular Flow With Interstitial Fluid","authors":"Yadong Wang, Wei Wu","doi":"10.1002/nag.3990","DOIUrl":"https://doi.org/10.1002/nag.3990","url":null,"abstract":"We present a constitutive model for the mechanical behavior of granular flow for both solid‐like and fluid‐like regimes. The stress rate tensor is decomposed into rate‐independent and rate‐dependent parts. The hypoplastic model is used for the rate‐independent part, while the ‐type rheological model is employed for the rate‐dependent part. The Stokes number is introduced to capture the influence of interstitial fluid viscosity within the rate‐dependent part of the model. The model performance is demonstrated through numerical simulations of element tests, encompassing both granular materials and granular‐fluid mixtures.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"52 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143857503","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}
The pot cover effect can increase the moisture content in shallow soil, which reduces subgrade strength and may lead to engineering issues, such as pavement cracks and deformation. Therefore, studying the prevention measures for the subgrade pot cover effect is essential. This paper proposes preventive measures, inspired by capillary barrier layers used in landfills, that involve installing such layers to mitigate the subgrade pot cover effect. First, a self‐designed test device was used to compare the hydrothermal changes in conventional fill subgrade and subgrade with gravel and sand capillary barrier layer in a seasonal frozen soil environment. Second, a water–vapor–heat coupling model was developed to simulate the quantitative changes in water migration induced by the capillary barrier layer during the experiment. Finally, the long‐term effect of using a capillary barrier layer to mitigate the pot cover effect on a loess subgrade in northwest China was simulated. The results show that at a depth of 2.5 cm, the liquid water content without a capillary barrier increases with the number of freeze–thaw cycles, reaching a maximum increase of 5.9%. In contrast, the maximum increase in liquid water content at the same depth in the soil layer with a capillary barrier is only 0.9%; the water vapor flux of the subgrade with a capillary barrier layer is 1/10 of that of the subgrade without a capillary barrier layer. The proposed capillary barrier layer method offers theoretical insights for mitigating the pot cover effect and guiding future subgrade designs.
{"title":"Feasibility Experiment and Simulation on Controlling the “Pot Cover Effect” of Subgrade in Seasonally Frozen Regions by Capillary Barrier Layer","authors":"Mingli Zhang, Ruiling Zhang, Yaling Chou, Peilin Zhao, Wei Feng, Duoyu Mi","doi":"10.1002/nag.3985","DOIUrl":"https://doi.org/10.1002/nag.3985","url":null,"abstract":"The pot cover effect can increase the moisture content in shallow soil, which reduces subgrade strength and may lead to engineering issues, such as pavement cracks and deformation. Therefore, studying the prevention measures for the subgrade pot cover effect is essential. This paper proposes preventive measures, inspired by capillary barrier layers used in landfills, that involve installing such layers to mitigate the subgrade pot cover effect. First, a self‐designed test device was used to compare the hydrothermal changes in conventional fill subgrade and subgrade with gravel and sand capillary barrier layer in a seasonal frozen soil environment. Second, a water–vapor–heat coupling model was developed to simulate the quantitative changes in water migration induced by the capillary barrier layer during the experiment. Finally, the long‐term effect of using a capillary barrier layer to mitigate the pot cover effect on a loess subgrade in northwest China was simulated. The results show that at a depth of 2.5 cm, the liquid water content without a capillary barrier increases with the number of freeze–thaw cycles, reaching a maximum increase of 5.9%. In contrast, the maximum increase in liquid water content at the same depth in the soil layer with a capillary barrier is only 0.9%; the water vapor flux of the subgrade with a capillary barrier layer is 1/10 of that of the subgrade without a capillary barrier layer. The proposed capillary barrier layer method offers theoretical insights for mitigating the pot cover effect and guiding future subgrade designs.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"108 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853337","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}
Energy pile technology is an environmentally sustainable and economically viable solution to achieve building thermal comfort. Energy pipe piles offer advantages over solid piles due to their inner hollow space, allowing for the installation of heat exchange tubes and optimization of backfill materials. Although the activation of an energy pile group can significantly promote the heat exchange performance for satisfying the energy demand of upper structures, there is currently no efficient calculation method available for the energy pipe pile group. Hence, this paper utilizes the coupled boundary element‐finite element method to investigate behaviors of energy pipe pile groups embedded in layered transversely isotropic soils, aiming to guide optimal design and accelerate application promotion. The proposed method's validity is confirmed through field tests and finite element simulations. Parametric analyses indicate that the reduction of pile thickness weakens the group effect, and the induced tensile forces in pipe piles under cooling conditions should be paid more attention when the pile spacing is large and the soil is stiff. Besides, a stiff bearing stratum minimizes the overall settlement and facilitates the uniform axial force distribution within energy pipe pile groups.
{"title":"Group Effects of Energy Pipe Piles Embedded in Layered Transversely Isotropic Soils Due to Thermo‐Mechanical Loading","authors":"Zhi Yong Ai, Lei Xu, Jia Ming Ye, Li‐Min Zhang","doi":"10.1002/nag.3989","DOIUrl":"https://doi.org/10.1002/nag.3989","url":null,"abstract":"Energy pile technology is an environmentally sustainable and economically viable solution to achieve building thermal comfort. Energy pipe piles offer advantages over solid piles due to their inner hollow space, allowing for the installation of heat exchange tubes and optimization of backfill materials. Although the activation of an energy pile group can significantly promote the heat exchange performance for satisfying the energy demand of upper structures, there is currently no efficient calculation method available for the energy pipe pile group. Hence, this paper utilizes the coupled boundary element‐finite element method to investigate behaviors of energy pipe pile groups embedded in layered transversely isotropic soils, aiming to guide optimal design and accelerate application promotion. The proposed method's validity is confirmed through field tests and finite element simulations. Parametric analyses indicate that the reduction of pile thickness weakens the group effect, and the induced tensile forces in pipe piles under cooling conditions should be paid more attention when the pile spacing is large and the soil is stiff. Besides, a stiff bearing stratum minimizes the overall settlement and facilitates the uniform axial force distribution within energy pipe pile groups.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"28 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847059","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}
Yingbin Liu, Shaoming Liao, Yaowen Yang, Junzuo He
The large torque generated by the rotary disk potentially causes the rolling of shield/tunnel boring machine (TBM), especially when it cuts rocks with over‐excavation or hard obstacles in very soft stratum, which further induces the torsion of assembled segments. In addition, the segment torsion may accumulate due to the unidirectional rotary cutting of shield/TBM over long distances. Excessive torsion of a tunnel induces track inclination, segment cracking, and bolt shearing failure. In the paper, a torsional shield‐lining on grouted foundation model was proposed to investigate the torsional behaviors of a segmental tunnel under the action of shield rolling and jack thrusting during tunneling. The segmental tunnel is regarded as a beam with reduced torsional stiffness, subjected to three‐dimensional foundation reactions and force boundary constrained by the shield. Besides, a grouted foundation model with longitudinal variable stiffness, accounting for the effect of grout solidification, was applied. The torque transferred from the rotary disk on segments was discussed, and the method to determine the longitudinal torsional stiffness of the segmental tunnel was introduced, considering the effect of shield rolling and jack thrusting. The proposed model was verified by two case studies, and a parametric analysis was conducted to investigate the effects of torque and the characteristics of grout material on structural responses. Additionally, the cumulative torsion of segments subjected to the unidirectional cutting of the shield was discussed. The proposed model and analytical results prove a valuable reference for tunnel anti‐torsion design and control measures of segment assembly.
{"title":"Torsional Behaviors of Segmental Tunnels Under the Action of Shield Rolling and Jack Thrusting During Tunneling","authors":"Yingbin Liu, Shaoming Liao, Yaowen Yang, Junzuo He","doi":"10.1002/nag.3987","DOIUrl":"https://doi.org/10.1002/nag.3987","url":null,"abstract":"The large torque generated by the rotary disk potentially causes the rolling of shield/tunnel boring machine (TBM), especially when it cuts rocks with over‐excavation or hard obstacles in very soft stratum, which further induces the torsion of assembled segments. In addition, the segment torsion may accumulate due to the unidirectional rotary cutting of shield/TBM over long distances. Excessive torsion of a tunnel induces track inclination, segment cracking, and bolt shearing failure. In the paper, a torsional shield‐lining on grouted foundation model was proposed to investigate the torsional behaviors of a segmental tunnel under the action of shield rolling and jack thrusting during tunneling. The segmental tunnel is regarded as a beam with reduced torsional stiffness, subjected to three‐dimensional foundation reactions and force boundary constrained by the shield. Besides, a grouted foundation model with longitudinal variable stiffness, accounting for the effect of grout solidification, was applied. The torque transferred from the rotary disk on segments was discussed, and the method to determine the longitudinal torsional stiffness of the segmental tunnel was introduced, considering the effect of shield rolling and jack thrusting. The proposed model was verified by two case studies, and a parametric analysis was conducted to investigate the effects of torque and the characteristics of grout material on structural responses. Additionally, the cumulative torsion of segments subjected to the unidirectional cutting of the shield was discussed. The proposed model and analytical results prove a valuable reference for tunnel anti‐torsion design and control measures of segment assembly.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"16 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143841328","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}
Hong‐jie Fang, Shun Wang, Xuan Kang, Dian‐qing Li, Wei Wu, Barbara Świtała
Accurate modeling of soil behavior under seismic conditions is critical for understanding and mitigating earthquake‐induced hazards. In this study, the Dyna–Simhypo model, an enhanced hypoplastic framework incorporating the intergranular strain tensor, is integrated with smoothed particle hydrodynamics (SPH) method for the first time to simulate co‐seismic large deformation processes of slopes. The model's performance is validated through cyclic triaxial tests, seismic wave propagation analysis, and large‐scale seismic slope simulations. Compared to the original Simhypo model, it eliminates ratcheting and reliably captures shear modulus reduction, damping buildup, and progressive soil degradation under cyclic loading. These advancements enable precise site response evaluations and accurate slope instability predictions, offering a robust tool for seismic hazard assessment.
{"title":"SPH Implementation of a Dynamic Hypoplastic Model for Seismic Large Deformation Analysis in Slopes","authors":"Hong‐jie Fang, Shun Wang, Xuan Kang, Dian‐qing Li, Wei Wu, Barbara Świtała","doi":"10.1002/nag.3984","DOIUrl":"https://doi.org/10.1002/nag.3984","url":null,"abstract":"Accurate modeling of soil behavior under seismic conditions is critical for understanding and mitigating earthquake‐induced hazards. In this study, the Dyna–Simhypo model, an enhanced hypoplastic framework incorporating the intergranular strain tensor, is integrated with smoothed particle hydrodynamics (SPH) method for the first time to simulate co‐seismic large deformation processes of slopes. The model's performance is validated through cyclic triaxial tests, seismic wave propagation analysis, and large‐scale seismic slope simulations. Compared to the original Simhypo model, it eliminates ratcheting and reliably captures shear modulus reduction, damping buildup, and progressive soil degradation under cyclic loading. These advancements enable precise site response evaluations and accurate slope instability predictions, offering a robust tool for seismic hazard assessment.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"218 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143827137","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}
Kamal Shaker, Morteza Eskandari‐Ghadi, Soheil Mohammadi
Investigating wave propagation in transversely isotropic saturated poroelastic material and introducing a family of stretched coordinate transformations to be used for defining a perfectly matched layer (PML) are the main aims of this paper. To this end, the formulation of Biot is adopted as the governing framework of the porous media. The coupled equations of motion and transport equation are uncoupled by means of the recently proposed two scalar potential functions in cylindrical coordinate system. Two separated families of continuous stretched coordinate transformations are introduced for each of radial and axial coordinates, which allows the whole half‐space to be replaced by a finite cylinder surrounded by an outer cylinder/cube with both finite height and radius. It is shown that the displacements and pore fluid pressure, determined from the analysis of the replaced cylindrical domain, is exactly collapsed on the analytical solution in the inner cylinder, while they are, based on the stretched coordinate transformation, attenuated very fast in the outer cylinder to prevent the reflection from the most exterior boundaries. The results of this study may be used in any wave propagation analysis containing either isotropic or transversely isotropic half‐ or full‐space.
{"title":"PML‐Based Family of Stretched Coordinate Systems for Wave Propagation in Poroelastic Transversely Isotropic Half‐Space","authors":"Kamal Shaker, Morteza Eskandari‐Ghadi, Soheil Mohammadi","doi":"10.1002/nag.3981","DOIUrl":"https://doi.org/10.1002/nag.3981","url":null,"abstract":"Investigating wave propagation in transversely isotropic saturated poroelastic material and introducing a family of stretched coordinate transformations to be used for defining a perfectly matched layer (PML) are the main aims of this paper. To this end, the formulation of Biot is adopted as the governing framework of the porous media. The coupled equations of motion and transport equation are uncoupled by means of the recently proposed two scalar potential functions in cylindrical coordinate system. Two separated families of continuous stretched coordinate transformations are introduced for each of radial and axial coordinates, which allows the whole half‐space to be replaced by a finite cylinder surrounded by an outer cylinder/cube with both finite height and radius. It is shown that the displacements and pore fluid pressure, determined from the analysis of the replaced cylindrical domain, is exactly collapsed on the analytical solution in the inner cylinder, while they are, based on the stretched coordinate transformation, attenuated very fast in the outer cylinder to prevent the reflection from the most exterior boundaries. The results of this study may be used in any wave propagation analysis containing either isotropic or transversely isotropic half‐ or full‐space.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"38 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824848","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}
The cover image is based on the article Can ChatGPT Implement Finite Element Models for Geotechnical Engineering Applications? by Taegu Kim et al., https://doi.org/10.1002/nag.3956.
{"title":"Cover Image, Volume 49, Issue 6","authors":"Taegu Kim, Tae Sup Yun, Hyoung Suk Suh","doi":"10.1002/nag.3980","DOIUrl":"https://doi.org/10.1002/nag.3980","url":null,"abstract":"<p>The cover image is based on the article <i>Can ChatGPT Implement Finite Element Models for Geotechnical Engineering Applications?</i> by Taegu Kim et al., https://doi.org/10.1002/nag.3956.\u0000\u0000 <figure>\u0000 <div><picture>\u0000 <source></source></picture><p></p>\u0000 </div>\u0000 </figure></p>","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"49 6","pages":"i"},"PeriodicalIF":3.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/nag.3980","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793403","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}
Compared with circular shield tunnels, quasi‐rectangular pipe‐jacking tunnels have the advantages of smaller construction disturbances and higher space utilization rates, which are widely applied in urban underground engineering. The carrying‐soil effect is a specific phenomenon during the construction of pipe‐jacking tunnels. To study the influence of carrying‐soil effect on the working face stability of a quasi‐rectangular pipe‐jacking tunnel, the collapse and blow‐out failure mechanisms of the working face are established on the basis of spatial discretization technique. By analysing the mechanical mechanism of the carrying‐soil effect, the upper bound solution of the critical chamber pressure of the working face that considers the carrying‐soil effect is obtained in this paper. Based on an actual project, the theoretical results are compared with the numerical results, proving the effectiveness of the proposed method. Furthermore, parametric analysis indicates that the jacking distance of the pipe‐jacking tunnel has a significant influence on the working face stability, while the influence of the frictional force between the soil and the pipe is relatively small.
{"title":"Working Face Stability Analysis of a Quasi‐Rectangular Pipe‐Jacking Tunnel Considering the Carrying‐Soil Effect","authors":"Fu Huang, Yongtao Wang, Min Zhang, Qiujing Pan","doi":"10.1002/nag.3982","DOIUrl":"https://doi.org/10.1002/nag.3982","url":null,"abstract":"Compared with circular shield tunnels, quasi‐rectangular pipe‐jacking tunnels have the advantages of smaller construction disturbances and higher space utilization rates, which are widely applied in urban underground engineering. The carrying‐soil effect is a specific phenomenon during the construction of pipe‐jacking tunnels. To study the influence of carrying‐soil effect on the working face stability of a quasi‐rectangular pipe‐jacking tunnel, the collapse and blow‐out failure mechanisms of the working face are established on the basis of spatial discretization technique. By analysing the mechanical mechanism of the carrying‐soil effect, the upper bound solution of the critical chamber pressure of the working face that considers the carrying‐soil effect is obtained in this paper. Based on an actual project, the theoretical results are compared with the numerical results, proving the effectiveness of the proposed method. Furthermore, parametric analysis indicates that the jacking distance of the pipe‐jacking tunnel has a significant influence on the working face stability, while the influence of the frictional force between the soil and the pipe is relatively small.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"16 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143805737","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}
The impacts of different types of methane hydrates (e.g., pore‐filling, load‐bearing, grain‐coating, and cementing types) on the mechanical properties of methane hydrate‐bearing sediments (MHBS) exhibit significant variations. However, the quantitative distinctions remain largely unexplored. Following the framework of the classical micromechanics‐based model, a simplified physical model of regularly arranged particle assembly is proposed for the coexistent‐type MHBS (the MHBS containing two or more types of hydrates) to derive the macroscopic constitutive relations, strength criteria, and corresponding macro–micro quantitative correlation of elastic and strength parameters. The obtained theoretical solutions are verified by comparison with indoor test results, and the influence of environmental factors and hydrate saturation, especially different types of hydrates, on the macroscopic mechanical properties of MHBS under various initial planar void ratios of sediments is investigated in detail. The results show that there are significant differences in the micromechanisms that affect the macroscopic mechanical properties of different hydrate types. Specifically, the load‐bearing hydrate has almost no contribution to the improvement of the elastic modulus and peak strength, while the cementing type plays a dominant role in the macroscopic mechanical properties of MHBS, and the influence of the hydrate with the grain‐coating type is between the load‐bearing and cementing types.
{"title":"Theoretical Analysis of Macroscopic Mechanical Properties of Coexistence Type Methane Hydrate‐Bearing Sediments by Micromechanics‐Based Model","authors":"Zhihao Zhou, Huaning Wang, Mingjing Jiang","doi":"10.1002/nag.3978","DOIUrl":"https://doi.org/10.1002/nag.3978","url":null,"abstract":"The impacts of different types of methane hydrates (e.g., pore‐filling, load‐bearing, grain‐coating, and cementing types) on the mechanical properties of methane hydrate‐bearing sediments (MHBS) exhibit significant variations. However, the quantitative distinctions remain largely unexplored. Following the framework of the classical micromechanics‐based model, a simplified physical model of regularly arranged particle assembly is proposed for the coexistent‐type MHBS (the MHBS containing two or more types of hydrates) to derive the macroscopic constitutive relations, strength criteria, and corresponding macro–micro quantitative correlation of elastic and strength parameters. The obtained theoretical solutions are verified by comparison with indoor test results, and the influence of environmental factors and hydrate saturation, especially different types of hydrates, on the macroscopic mechanical properties of MHBS under various initial planar void ratios of sediments is investigated in detail. The results show that there are significant differences in the micromechanisms that affect the macroscopic mechanical properties of different hydrate types. Specifically, the load‐bearing hydrate has almost no contribution to the improvement of the elastic modulus and peak strength, while the cementing type plays a dominant role in the macroscopic mechanical properties of MHBS, and the influence of the hydrate with the grain‐coating type is between the load‐bearing and cementing types.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"6 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143805736","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}
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