Pub Date : 2024-09-24DOI: 10.1016/j.trgeo.2024.101386
Cungang Lin , Zhongjie Wang , Zhongqiang Liu , Xianghuan Luo , Baosong Ma , Yu Chen
Prevailing analytical approaches for tunnelling-induced soil-pipeline interactions predominantly rely on linear analyses, limiting their applicability in nonlinear scenarios. This study introduces a novel tensionless Winkler solution that accounts for gap formation and soil yielding, validated against three well-documented experiments and demonstrating superiority over existing Winkler solutions. Additionally, plate load tests refine traditional soil-bearing theories for buried pipelines in sand, providing subgrade stiffness and ultimate bearing capacity values pertinent to tunnelling-induced interactions. Parametric studies highlight amplified nonlinearity in pipeline behaviours with increased pipeline flexural rigidity and tunnel volume loss, due to soil-pipeline separation and subgrade yielding. Notably, ignoring gap formation and soil yielding leads to overly conservative estimations of pipeline deflections and bending moments. Higher subgrade moduli increase pipeline strains, while enhanced subgrade bearing capacity above the pipeline prevents soil yielding, rendering its effect negligible, whereas the bearing capacity beneath the pipeline is inconsequential in tunnelling scenarios.
{"title":"Tunnelling-induced nonlinear responses of continuous pipelines resting on tensionless Winkler foundation","authors":"Cungang Lin , Zhongjie Wang , Zhongqiang Liu , Xianghuan Luo , Baosong Ma , Yu Chen","doi":"10.1016/j.trgeo.2024.101386","DOIUrl":"10.1016/j.trgeo.2024.101386","url":null,"abstract":"<div><div>Prevailing analytical approaches for tunnelling-induced soil-pipeline interactions predominantly rely on linear analyses, limiting their applicability in nonlinear scenarios. This study introduces a novel tensionless Winkler solution that accounts for gap formation and soil yielding, validated against three well-documented experiments and demonstrating superiority over existing Winkler solutions. Additionally, plate load tests refine traditional soil-bearing theories for buried pipelines in sand, providing subgrade stiffness and ultimate bearing capacity values pertinent to tunnelling-induced interactions. Parametric studies highlight amplified nonlinearity in pipeline behaviours with increased pipeline flexural rigidity and tunnel volume loss, due to soil-pipeline separation and subgrade yielding. Notably, ignoring gap formation and soil yielding leads to overly conservative estimations of pipeline deflections and bending moments. Higher subgrade moduli increase pipeline strains, while enhanced subgrade bearing capacity above the pipeline prevents soil yielding, rendering its effect negligible, whereas the bearing capacity beneath the pipeline is inconsequential in tunnelling scenarios.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101386"},"PeriodicalIF":4.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422792","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}
Many bridges are constructed over waterways, exposing their support systems to scour caused by flowing water-induced bed shear stresses over time. This study focuses on analysing the local scour beneath an abutment, which led to the collapse of a poorly reinforced concrete bridge in Italy. The analysis investigates the causes of the collapse on the basis of a geotechnical characterisation of the subsoil foundation and mechanics characterisation of the abutment. By estimating the scour amplitude below the abutment, an advanced Finite Element fracture mechanics model was used to study the collapse of the bridge. The study makes it possible to assess the probability of collapse based on the scour width beneath the abutment and offer an approach to assess the safety of infrastructure. Finally, the results show that the empirical model for shear capacity is overly unconservative and sometimes unreliable in this special context. and therefore failure should be predicted from the fracture mechanics based on adopting appropriate reduction factors for shear capacity.
{"title":"Risk-based probabilistic assessment of a bridge collapse due to abutments scour. A case study","authors":"Ferdinando Totani , Angelo Aloisio , Michele Angiolilli , Danilo Ranalli","doi":"10.1016/j.trgeo.2024.101369","DOIUrl":"10.1016/j.trgeo.2024.101369","url":null,"abstract":"<div><div>Many bridges are constructed over waterways, exposing their support systems to scour caused by flowing water-induced bed shear stresses over time. This study focuses on analysing the local scour beneath an abutment, which led to the collapse of a poorly reinforced concrete bridge in Italy. The analysis investigates the causes of the collapse on the basis of a geotechnical characterisation of the subsoil foundation and mechanics characterisation of the abutment. By estimating the scour amplitude below the abutment, an advanced Finite Element fracture mechanics model was used to study the collapse of the bridge. The study makes it possible to assess the probability of collapse based on the scour width beneath the abutment and offer an approach to assess the safety of infrastructure. Finally, the results show that the empirical model for shear capacity is overly unconservative and sometimes unreliable in this special context. and therefore failure should be predicted from the fracture mechanics based on adopting appropriate reduction factors for shear capacity.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101369"},"PeriodicalIF":4.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356637","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}
Pub Date : 2024-09-20DOI: 10.1016/j.trgeo.2024.101382
Yu Su , Yu-Jun Cui , Jean-Claude Dupla , Jean Canou
An interlayer was formed in the conventional railway track, due to the interpenetration between ballast grains and subgrade fines under the effect of train circulation. Considering the interlayer’s high bearing capacity, it has been remained in the railway track in its renewal program. In present study, the mechanical behaviors of such fine/coarse soil mixture were experimentally explored and theoretically modeled. Results show that: (i) the soil–water retention curve (SWRC) of mixture was solely related to the dry density of fine soil ρd-f, while independent of the coarse grain content fv; (ii) two various fabrics of mixture were distinguished by a characteristic fv-cha value: a fine matrix macrostructure when fv < fv-cha and a coarse grain dominated fabric when fv > fv-cha; (iii) an increasing water content induced the growth of permanent strain and a decline of resilient modulus Mr due to the decline of suction , but the growth of damping ratio Dr due to the rise of soil viscosity; (iv) a constitutive model was developed for the by incorporating the SWRC, which allows the influences of the number of loading cycles N, deviator stress σd and fv to be considered. A constitutive model was also proposed for the Mr, taking the influences of σd, and fv into account.
{"title":"Experimental investigation and modelling of the mechanical behaviors of fine/coarse soil mixture","authors":"Yu Su , Yu-Jun Cui , Jean-Claude Dupla , Jean Canou","doi":"10.1016/j.trgeo.2024.101382","DOIUrl":"10.1016/j.trgeo.2024.101382","url":null,"abstract":"<div><div>An interlayer was formed in the conventional railway track, due to the interpenetration between ballast grains and subgrade fines under the effect of train circulation. Considering the interlayer’s high bearing capacity, it has been remained in the railway track in its renewal program. In present study, the mechanical behaviors of such fine/coarse soil mixture were experimentally explored and theoretically modeled. Results show that: (i) the soil–water retention curve (SWRC) of mixture was solely related to the dry density of fine soil <em>ρ</em><sub>d-f</sub>, while independent of the coarse grain content <em>f</em><sub>v</sub>; (ii) two various fabrics of mixture were distinguished by a characteristic <em>f</em><sub>v-cha</sub> value: a fine matrix macrostructure when <em>f</em><sub>v</sub> < <em>f</em><sub>v-cha</sub> and a coarse grain dominated fabric when <em>f</em><sub>v</sub> > <em>f</em><sub>v-cha</sub>; (iii) an increasing water content induced the growth of permanent strain <span><math><msubsup><mi>ε</mi><mrow><mn>1</mn></mrow><mi>p</mi></msubsup></math></span> and a decline of resilient modulus <em>M</em><sub>r</sub> due to the decline of suction <span><math><mi>ψ</mi></math></span>, but the growth of damping ratio <em>D</em><sub>r</sub> due to the rise of soil viscosity; (iv) a constitutive model was developed for the <span><math><msubsup><mi>ε</mi><mrow><mn>1</mn></mrow><mi>p</mi></msubsup></math></span> by incorporating the SWRC, which allows the influences of the number of loading cycles <em>N</em>, deviator stress <em>σ</em><sub>d</sub> and <em>f</em><sub>v</sub> to be considered. A constitutive model was also proposed for the <em>M</em><sub>r</sub>, taking the influences of <em>σ</em><sub>d</sub>,<span><math><mi>ψ</mi></math></span> and <em>f</em><sub>v</sub> into account.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101382"},"PeriodicalIF":4.9,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356641","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}
High-speed train (HST) running in the saturated soft ground induces significant vibration that may threaten the running safety and serviceability of high-speed railway (HSR). Extensive studies have been conducted on the dynamic responses of HSR, yet, the soil–water coupling and plastic behavior in the saturated soft ground are rarely considered, and thus the build-up of excess pore water pressure (EPWP) and displacement cannot be accurately calculated. In this study, 2D soil–water coupling elastoplastic FEM was employed to investigate HST induced vibration in the pile-supported embankment using FE code called DBLEAVES. Dynamic soil stress, EPWP, acceleration and displacement under different cases were numerically analyzed in detail. Numerical tests confirm that liquid phase in soft ground plays important influence on the dynamic responses that vertical acceleration and displacement will be overestimated while the horizontal acceleration and displacement as well as EPWP will be underestimated if soil–water coupling is not considered. Single-phase analysis also exaggerates the acceleration attenuation and underestimate the vibration amplification in soft ground. The existence of piles can induce significant soil arching effect in the embankment, the distributions of vertical acceleration and EPWP are partitioned sharply by the piles while vertical displacement in soft ground becomes more uniform along the depth direction within the pile reinforced area. The existence of piles also induces stronger vibration beneath the pile end so that larger EPWP is generated below the pile end than around the pile body. The main influence area due to HST vibration for pile-supported embankment is overall 20 m away from the centerline of HSR track, therefore, it is reasonable to improve the ground by properly increasing the number of pile within this area. When the number of pile is determined, increasing the length of pile or reducing the pile spacing are two effective ways to mitigate the dynamic response.
{"title":"Numerical tests on dynamic response of pile-supported reclaimed embankment for high-speed railway in saturated soft ground using soil–water coupling elastoplastic FEM","authors":"Qiang Huang , Zhengyang Cui , Hiromasa Iwai , Yini Zhong , Feng Zhang","doi":"10.1016/j.trgeo.2024.101374","DOIUrl":"10.1016/j.trgeo.2024.101374","url":null,"abstract":"<div><div>High-speed train (HST) running in the saturated soft ground induces significant vibration that may threaten the running safety and serviceability of high-speed railway (HSR). Extensive studies have been conducted on the dynamic responses of HSR, yet, the soil–water coupling and plastic behavior in the saturated soft ground are rarely considered, and thus the build-up of excess pore water pressure (EPWP) and displacement cannot be accurately calculated. In this study, 2D soil–water coupling elastoplastic FEM was employed to investigate HST induced vibration in the pile-supported embankment using FE code called DBLEAVES. Dynamic soil stress, EPWP, acceleration and displacement under different cases were numerically analyzed in detail. Numerical tests confirm that liquid phase in soft ground plays important influence on the dynamic responses that vertical acceleration and displacement will be overestimated while the horizontal acceleration and displacement as well as EPWP will be underestimated if soil–water coupling is not considered. Single-phase analysis also exaggerates the acceleration attenuation and underestimate the vibration amplification in soft ground. The existence of piles can induce significant soil arching effect in the embankment, the distributions of vertical acceleration and EPWP are partitioned sharply by the piles while vertical displacement in soft ground becomes more uniform along the depth direction within the pile reinforced area. The existence of piles also induces stronger vibration beneath the pile end so that larger EPWP is generated below the pile end than around the pile body. The main influence area due to HST vibration for pile-supported embankment is overall 20 m away from the centerline of HSR track, therefore, it is reasonable to improve the ground by properly increasing the number of pile within this area. When the number of pile is determined, increasing the length of pile or reducing the pile spacing are two effective ways to mitigate the dynamic response.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101374"},"PeriodicalIF":4.9,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214391224001958/pdfft?md5=3e92c2fcb1e2fa30ef324a59125c821b&pid=1-s2.0-S2214391224001958-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315127","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}
Pub Date : 2024-09-19DOI: 10.1016/j.trgeo.2024.101381
Chenlei Jiao , Jun Peng , Yu Diao , Gang Zheng , Jiangang Han
The issue of bridge end bumps is a critical concern in the failure of bridge and bridge approaches. A series of novel centrifuge tests utilizing a ring model box were conducted to investigate settlement and its induced damages at the bridge approach. A new mitigation method, the deep-seated slab, for bridge end bumps was modeled in the test. This study analyzed the decisive role of pavement stiffness, soil modulus, and load cycles on deformation from the perspective of structure-soil interaction under standard traffic load conditions. The test results show that when deep-seated slabs are used, the deformation of the bridge approach follows an exponential decay pattern, eventually stabilizing after approximately one slab length. Furthermore, the upper and lower bridges exhibit distinct damage modes, i.e., the bridge damage by wheel collision at the upper bridge and the pavement damage by wheel impact at the lower bridge. The damage zone on the pavement is approximately 1.7 times the wheel width and the damage zone on the bridge 2.6 times. Finally, a predictive model for the deformation of bridge approaches was proposed, considering the effect of pavement stiffness, subgrade soil modulus, and load cycles. The relationship between the deformation and the three normalized variables conforms to the quadratic polynomial function.
{"title":"Centrifuge tests study on settlement and damage modes of bridge approaches using deep-seated slab","authors":"Chenlei Jiao , Jun Peng , Yu Diao , Gang Zheng , Jiangang Han","doi":"10.1016/j.trgeo.2024.101381","DOIUrl":"10.1016/j.trgeo.2024.101381","url":null,"abstract":"<div><div>The issue of bridge end bumps is a critical concern in the failure of bridge and bridge approaches. A series of novel centrifuge tests utilizing a ring model box were conducted to investigate settlement and its induced damages at the bridge approach. A new mitigation method, the deep-seated slab, for bridge end bumps was modeled in the test. This study analyzed the decisive role of pavement stiffness, soil modulus, and load cycles on deformation from the perspective of structure-soil interaction under standard traffic load conditions. The test results show that when deep-seated slabs are used, the deformation of the bridge approach follows an exponential decay pattern, eventually stabilizing after approximately one slab length. Furthermore, the upper and lower bridges exhibit distinct damage modes, i.e., the bridge damage by wheel collision at the upper bridge and the pavement damage by wheel impact at the lower bridge. The damage zone on the pavement is approximately 1.7 times the wheel width and the damage zone on the bridge 2.6 times. Finally, a predictive model for the deformation of bridge approaches was proposed, considering the effect of pavement stiffness, subgrade soil modulus, and load cycles. The relationship between the deformation and the three normalized variables conforms to the quadratic polynomial function.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101381"},"PeriodicalIF":4.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311848","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}
Pub Date : 2024-09-19DOI: 10.1016/j.trgeo.2024.101380
He Huang , Wan-Huan Zhou , Su Qin , Adam Bezuijen
Fulfilling the role of a soil conditioner, foam plays a pivotal role in Earth Pressure Balance (EPB) shield tunnelling by enhancing soil properties such as lowering permeability and increasing flowability. This study introduces a macro-model designed to quantify foam penetration behaviour in saturated sand, utilising rheological properties. To validate this model, experiments were conducted to replicate the foam penetration behaviour. Six sand beds characterised by varying particle sizes, along with foam having an expansion ratio of fifteen, were employed for penetration tests under different hydraulic conditions utilising a sand column device. The rheological profile of the foam is described by the power-law model, as also found by rheometer tests, although with different parameters. The flow behaviour of foam within the sand column conforms to the flow equation that governs power-law fluids in porous media. The developed model effectively predicts the foam penetration process under varying hydraulic conditions compared with the experimental results. Furthermore, the fitting results of the experimental data indicate that the flow behaviour index of the foam remains approximately 0.09 across all tests, regardless of the type of sand used. In contrast, the model-derived generalised permeability coefficient strongly correlates with the effective particle size (d10) of the sand bed. Overall, the model effectively quantifies the foam penetration behaviour, accounting for changes in infiltration velocity and pore water pressure, which is essential for understanding the transfer of support pressure in EPB shield tunnelling.
{"title":"A simple model incorporating foam rheology to quantify foam penetration behaviour in EPB shield tunnelling","authors":"He Huang , Wan-Huan Zhou , Su Qin , Adam Bezuijen","doi":"10.1016/j.trgeo.2024.101380","DOIUrl":"10.1016/j.trgeo.2024.101380","url":null,"abstract":"<div><div>Fulfilling the role of a soil conditioner, foam plays a pivotal role in Earth Pressure Balance (EPB) shield tunnelling by enhancing soil properties such as lowering permeability and increasing flowability. This study introduces a macro-model designed to quantify foam penetration behaviour in saturated sand, utilising rheological properties. To validate this model, experiments were conducted to replicate the foam penetration behaviour. Six sand beds characterised by varying particle sizes, along with foam having an expansion ratio of fifteen, were employed for penetration tests under different hydraulic conditions utilising a sand column device. The rheological profile of the foam is described by the power-law model, as also found by rheometer tests, although with different parameters. The flow behaviour of foam within the sand column conforms to the flow equation that governs power-law fluids in porous media. The developed model effectively predicts the foam penetration process under varying hydraulic conditions compared with the experimental results. Furthermore, the fitting results of the experimental data indicate that the flow behaviour index of the foam remains approximately 0.09 across all tests, regardless of the type of sand used. In contrast, the model-derived generalised permeability coefficient strongly correlates with the effective particle size (<em>d</em><sub>10</sub>) of the sand bed. Overall, the model effectively quantifies the foam penetration behaviour, accounting for changes in infiltration velocity and pore water pressure, which is essential for understanding the transfer of support pressure in EPB shield tunnelling.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101380"},"PeriodicalIF":4.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356642","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}
Pub Date : 2024-09-19DOI: 10.1016/j.trgeo.2024.101377
Georgios Rempelos , Giacomo Ognibene , Louis Le Pen , Simon Blainey , John Preston , William Powrie
There has been a railway renaissance in Britain since the 1990s, with passenger kilometres approximately doubling between 1990 and 2019. Despite changing habits caused by the COVID-19 pandemic, the latest data show that passenger journeys are almost back to their 2019 levels. Without building new lines (HS2 being not yet open and recently downgraded in scope), increased use has led to increased rates of infrastructure deterioration and a need for more maintenance and renewal to create the capacity on the aged existing railway network to meet this demand. Against this background, there have been on-going efforts in the field of railway track deterioration modelling to limit component failures and prolong the remaining useful life of the infrastructure. Analysis and modelling techniques have become increasingly detailed owing to advances in real-time data-acquisition and computational methods and the emergence of ‘big data’ approaches to interpretation. However, previous studies have generally merely confirmed the complexity of modelling track deterioration. There are few if any systematic reviews of deterioration models aimed at informing infrastructure managers (IM) from a whole-life asset management perspective. This paper addresses this knowledge gap by building on previous research to present a systematic taxonomy of track deterioration models, and proposing a hierarchical classification based on level of detail and functionality.
{"title":"Railway Track Deterioration Models: A Review of the State of the Art","authors":"Georgios Rempelos , Giacomo Ognibene , Louis Le Pen , Simon Blainey , John Preston , William Powrie","doi":"10.1016/j.trgeo.2024.101377","DOIUrl":"10.1016/j.trgeo.2024.101377","url":null,"abstract":"<div><div>There has been a railway renaissance in Britain since the 1990s, with passenger kilometres approximately doubling between 1990 and 2019. Despite changing habits caused by the COVID-19 pandemic, the latest data show that passenger journeys are almost back to their 2019 levels. Without building new lines (HS2 being not yet open and recently downgraded in scope), increased use has led to increased rates of infrastructure deterioration and a need for more maintenance and renewal to create the capacity on the aged existing railway network to meet this demand. Against this background, there have been on-going efforts in the field of railway track deterioration modelling to limit component failures and prolong the remaining useful life of the infrastructure. Analysis and modelling techniques have become increasingly detailed owing to advances in real-time data-acquisition and computational methods and the emergence of ‘big data’ approaches to interpretation. However, previous studies have generally merely confirmed the complexity of modelling track deterioration. There are few if any systematic reviews of deterioration models aimed at informing infrastructure managers (IM) from a whole-life asset management perspective. This paper addresses this knowledge gap by building on previous research to present a systematic taxonomy of track deterioration models, and proposing a hierarchical classification based on level of detail and functionality.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101377"},"PeriodicalIF":4.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319126","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}
Pub Date : 2024-09-18DOI: 10.1016/j.trgeo.2024.101378
Xinyu Ye , Sheng Zhang , Yu Lei , Yi Jiang , Yang Chen , Menghong Chen
To satisfy the economic requirements and reduce the impact to the surrounding buildings and underground structures, the dynamic compaction (heavy tamping) and static compaction are combined used in the soil filling for airport subgrade. Despite compaction the subgrades in the same degree of compaction, the subgrades filled by dynamic and static compaction method show different increase potential in the permanent strain under cyclic loading, which then further result in the differential settlement and safety problems. This study firstly investigated the compaction characteristics under static compaction and different dynamic compaction scheme, during which the static and dynamic compaction strain and stress evolutions were monitored. The cyclic triaxial tests were then performed to investigate the sample preparation method derived difference in permanent strain under cyclic loading. Furthermore, to provide a microscopic interpretation to this difference, the pore size distributions of the silt samples based on mercury intrusion porosimetry (MIP) test and the internal particle contact stresses from discrete element method (DEM) simulation were respectively explored. The main conclusions are as follows: (1) The dynamic compaction processes can be divided into rapid and slow compaction strain stages determined by strain growth rate and compaction numbers, which further influences the homogeneity of soil samples; (2) The statically compacted samples have more significant permanent strain than the dynamic ones due to the localized stress concentration and different pore microstructures; the permanent strain increases with dynamic compaction energy until a stable stage is reached. (3) The MIP results show that the dynamic compaction transforms the macropores into mesopores; the higher compaction energy enhances this transforming effect but results in a decrease in the overall homogeneity.
{"title":"Dynamic and static compaction methods deriving different strain evolutions under cyclic loading for silt and its microscopic interpretation","authors":"Xinyu Ye , Sheng Zhang , Yu Lei , Yi Jiang , Yang Chen , Menghong Chen","doi":"10.1016/j.trgeo.2024.101378","DOIUrl":"10.1016/j.trgeo.2024.101378","url":null,"abstract":"<div><p>To satisfy the economic requirements and reduce the impact to the surrounding buildings and underground structures, the dynamic compaction (heavy tamping) and static compaction are combined used in the soil filling for airport subgrade. Despite compaction the subgrades in the same degree of compaction, the subgrades filled by dynamic and static compaction method show different increase potential in the permanent strain under cyclic loading, which then further result in the differential settlement and safety problems. This study firstly investigated the<!--> <!-->compaction characteristics under static compaction and different dynamic compaction scheme, during which the static and dynamic compaction strain and stress evolutions were monitored. The cyclic triaxial tests were then performed to investigate the sample preparation method derived difference in permanent strain under cyclic loading. Furthermore, to provide a microscopic interpretation to this difference, the pore size distributions of the silt samples based on mercury intrusion porosimetry (MIP) test and the internal particle contact stresses from discrete element method (DEM) simulation were respectively explored. The main conclusions are as follows: (1) The dynamic compaction processes can be divided into rapid and slow compaction strain stages determined by strain growth rate and compaction numbers, which further influences the homogeneity of soil samples; (2) The statically compacted samples have more significant permanent strain than the dynamic ones due to the localized stress concentration and different pore microstructures; the permanent strain increases with dynamic compaction energy until a stable stage is reached. (3) The MIP results show that the dynamic compaction transforms<!--> <!-->the macropores into mesopores; the higher compaction energy enhances this transforming effect but results in a decrease in the overall homogeneity.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101378"},"PeriodicalIF":4.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270297","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}
Pub Date : 2024-09-14DOI: 10.1016/j.trgeo.2024.101376
Yu-Xuan Liu, Chao-Min Shen, Si-Hong Liu, Yuan-Sheng Liu, Chen-Geng Liu
Particle breakage of granular materials under cyclic shearing is related to a variety of engineering problems in geotechnical and transportation engineering. However, there is limited understanding regarding the detailed evolution law of breakage under cyclic shearing. To this end, a series of cyclic simple shear tests were conducted on artificially dyed gypsum particles. It was observed that, in contrast to the particle size distribution of the whole sample, the fractional particle size distributions of gap-graded samples followed a unified breakage evolution path as those of the uniformly graded ones and tended towards fractional fractal distributions. These results have inspired the introduction of the fractional breakage index. Moreover, the breakage-plastic work relationship was further extended to describe the breakage of fractional particles, incorporating the effect of the number of cycles on the plastic work distribution. Finally, based on the concept of breakage-packing, a predictive model for plastic work-breakage-deformation of crushable granular materials under cyclic shearing was proposed. These results have the potential in understanding the detailed particle breakage evolution and establishing a predictive framework for the breakage-induced deformation of crushable granular materials.
{"title":"Detailed particle breakage of crushable granular materials under cyclic shearing conditions using dyed gypsum technique","authors":"Yu-Xuan Liu, Chao-Min Shen, Si-Hong Liu, Yuan-Sheng Liu, Chen-Geng Liu","doi":"10.1016/j.trgeo.2024.101376","DOIUrl":"10.1016/j.trgeo.2024.101376","url":null,"abstract":"<div><p>Particle breakage of granular materials under cyclic shearing is related to a variety of engineering problems in geotechnical and transportation engineering. However, there is limited understanding regarding the detailed evolution law of breakage under cyclic shearing. To this end, a series of cyclic simple shear tests were conducted on artificially dyed gypsum particles. It was observed that, in contrast to the particle size distribution of the whole sample, the fractional particle size distributions of gap-graded samples followed a unified breakage evolution path as those of the uniformly graded ones and tended towards fractional fractal distributions. These results have inspired the introduction of the fractional breakage index. Moreover, the breakage-plastic work relationship was further extended to describe the breakage of fractional particles, incorporating the effect of the number of cycles on the plastic work distribution. Finally, based on the concept of breakage-packing, a predictive model for plastic work-breakage-deformation of crushable granular materials under cyclic shearing was proposed. These results have the potential in understanding the detailed particle breakage evolution and establishing a predictive framework for the breakage-induced deformation of crushable granular materials.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101376"},"PeriodicalIF":4.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270295","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 determination of S-wave velocity (Vs) is of significant importance in various engineering disciplines, including mining, civil, and geotechnical engineering. It is beneficial to indirectly determine Vs under both dry and saturated conditions and to understand its relationship with influencing input variables: coring depth (H), durability index (DI), water content (Wa), dry density (ρd), saturated density (ρs), and porosity (n). In this study, we evaluate these relationships using three multiple machine-learning algorithms (MLAs): artificial neural network (ANN), fuzzy inference system (FIS), and gene expression programming (GEP), alongside a linear regression method (LRM) and predict both dry S-wave velocity (Vs-dry) and saturated S-wave velocity (Vs-sat) of rocks. The research involves the analysis of 90 datasets derived from samples of schist, phyllite, and sandstone rocks collected from Azad and Bakhtiari dam sites in Iran. The diversity of these datasets is a key advantage of this study, providing a solid foundation for models training and testing while enhancing the models’ generalizability. Model optimization techniques are employed in the Python, MATLAB, GenXProTools, and SPSS environments to identify the most effective versions of ANN, FIS, GEP, and LRM models, respectively. The prediction performance analysis reveals that all applied models yield acceptable levels of accuracy for predicting Vs-dry and Vs-sat. However, GEP emerges as the best model for predicting both Vs-dry and Vs-sat. The ANN and FIS models also achieve high levels of accuracy, while LRM performs comparatively less well. Additionally, sensitivity analysis conducted using the cosine amplitude method (CAM) highlights the influence of different variables on Vs-dry and Vs-sat. The ρd is found to be the most influential parameter on Vs-dry, whereas DI exhibits the least impact. Conversely, the ρs significantly affects Vs-sat, while Wa shows the lowest impact. The exceptional performance of these proposed MLAs confirms their applicability in real-world rock engineering and geotechnics projects, offering precise determination of Vs. The diversity of studied rock types and datasets, along with the use of cost-effective and easy measurable inputs, the determination of Vs in both dry and saturated status, and the application of robust MLAs for Vs determination are the main novelties of this study. However, further researches involving additional datasets and more rock types are required to validate these findings.
S 波速度（Vs）的测定在采矿、土木和岩土工程等多个工程学科中都具有重要意义。在干燥和饱和条件下间接测定 Vs 并了解其与影响输入变量（取芯深度 (H)、耐久性指数 (DI)、含水量 (Wa)、干密度 (ρd)、饱和密度 (ρs) 和孔隙度 (n) ）之间的关系非常有益。在本研究中，我们使用三种多重机器学习算法（MLAs）：人工神经网络（ANN）、模糊推理系统（FIS）和基因表达编程（GEP），结合线性回归方法（LRM）对这些关系进行了评估，并预测了岩石的干 S 波速度（Vs-dry）和饱和 S 波速度（Vs-sat）。研究涉及对 90 个数据集的分析，这些数据集来自伊朗阿扎德和巴赫蒂亚里坝址采集的片岩、辉绿岩和砂岩样本。这些数据集的多样性是本研究的主要优势，为模型的训练和测试提供了坚实的基础，同时增强了模型的普适性。在 Python、MATLAB、GenXProTools 和 SPSS 环境中分别采用了模型优化技术，以确定最有效的 ANN、FIS、GEP 和 LRM 模型版本。预测性能分析表明，所有应用模型预测 Vs-dry 和 Vs-sat 的准确度都达到了可接受的水平。然而，GEP 是预测 Vs-dry 和 Vs-sat 的最佳模型。ANN 和 FIS 模型也达到了较高的准确度，而 LRM 模型的准确度相对较低。此外，使用余弦振幅法（CAM）进行的敏感性分析凸显了不同变量对 Vs-dry 和 Vs-sat 的影响。结果发现，ρd 是对 Vs-dry 影响最大的参数，而 DI 的影响最小。相反，ρs 对 Vs-sat 的影响很大，而 Wa 的影响最小。这些拟议工作重点的卓越性能证实了它们在实际岩石工程和岩土工程项目中的适用性，可提供 Vs 的精确测定。所研究岩石类型和数据集的多样性，以及所使用的具有成本效益且易于测量的输入数据、干燥和饱和状态下的 Vs 测定，以及应用稳健的 MLA 进行 Vs 测定，是本研究的主要创新点。不过，要验证这些发现，还需要涉及更多数据集和更多岩石类型的进一步研究。
{"title":"Improved determination of the S-wave velocity of rocks in dry and saturated conditions: Application of machine-learning algorithms","authors":"Mohammad Rezaei , Seyedeh Rahele Ahmadi , Hoang Nguyen , Danial Jahed Armaghani","doi":"10.1016/j.trgeo.2024.101371","DOIUrl":"10.1016/j.trgeo.2024.101371","url":null,"abstract":"<div><p>The determination of S-wave velocity (V<sub>s</sub>) is of significant importance in various engineering disciplines, including mining, civil, and geotechnical engineering. It is beneficial to indirectly determine V<sub>s</sub> under both dry and saturated conditions and to understand its relationship with influencing input variables: coring depth (H), durability index (DI), water content (W<sub>a</sub>), dry density (ρ<sub>d</sub>), saturated density (ρ<sub>s</sub>), and porosity (n). In this study, we evaluate these relationships using three multiple machine-learning algorithms (MLAs): artificial neural network (ANN), fuzzy inference system (FIS), and gene expression programming (GEP), alongside a linear regression method (LRM) and predict both dry S-wave velocity (V<sub>s-dry</sub>) and saturated S-wave velocity (V<sub>s-sat</sub>) of rocks. The research involves the analysis of 90 datasets derived from samples of schist, phyllite, and sandstone rocks collected from Azad and Bakhtiari dam sites in Iran. The diversity of these datasets is a key advantage of this study, providing a solid foundation for models training and testing while enhancing the models’ generalizability. Model optimization techniques are employed in the Python, MATLAB, GenXProTools, and SPSS environments to identify the most effective versions of ANN, FIS, GEP, and LRM models, respectively. The prediction performance analysis reveals that all applied models yield acceptable levels of accuracy for predicting V<sub>s-dry</sub> and V<sub>s-sat</sub>. However, GEP emerges as the best model for predicting both V<sub>s-dry</sub> and V<sub>s-sat</sub>. The ANN and FIS models also achieve high levels of accuracy, while LRM performs comparatively less well. Additionally, sensitivity analysis conducted using the cosine amplitude method (CAM) highlights the influence of different variables on V<sub>s-dry</sub> and V<sub>s-sat</sub>. The ρ<sub>d</sub> is found to be the most influential parameter on V<sub>s-dry</sub>, whereas DI exhibits the least impact. Conversely, the ρ<sub>s</sub> significantly affects V<sub>s-sat</sub>, while W<sub>a</sub> shows the lowest impact. The exceptional performance of these proposed MLAs confirms their applicability in real-world rock engineering and geotechnics projects, offering precise determination of V<sub>s</sub>. The diversity of studied rock types and datasets, along with the use of cost-effective and easy measurable inputs, the determination of V<sub>s</sub> in both dry and saturated status, and the application of robust MLAs for V<sub>s</sub> determination are the main novelties of this study. However, further researches involving additional datasets and more rock types are required to validate these findings.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101371"},"PeriodicalIF":4.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142239065","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号