Steel slag and tyre chips are two waste products with potential for sustainable use in railway tracks.
While the previous studies have primarily focused on the benefits of utilizing steel slag as railway subballast, yet its suitability as railway ballast with and without tyre chips (TC) has not been comprehensively investigated. Moreover, the possible effect of coal fouling on the performance of TC-intermixed steel slag ballast is yet to be studied. Therefore, the current study assessed the influence of TC on the performance of slag-granite ballast mixture under coal-fouled condition using large-scale track simulation test (TST) and constant-head permeability apparatus. TST results indicated that vertical and lateral deformations of ballast increased, while the track stiffness (k) and ballast breakage index (BBI) decreased with the increase in proportion of tyre chips. The threshold content of tyre chips to be mixed with steel slag ballast (SSB) is identified as 10%. The study further established that the addition of coal leads to an increase in deformations, while reducing BBI of TC intermixed slag-granite ballast. Moreover, the addition of coal causes a significant reduction in hydraulic conductivity of the TC intermixed ballast. Further, the critical value of void contamination index is determined to be 25%.
{"title":"Deformation and degradation behaviour of coal-fouled tyre chips intermixed steel slag ballast under cyclic loading","authors":"Atif Hussain , Syed Khaja Karimullah Hussaini , Buddhima Indraratna , Yujie Qi","doi":"10.1016/j.trgeo.2025.101869","DOIUrl":"10.1016/j.trgeo.2025.101869","url":null,"abstract":"<div><div>Steel slag and tyre chips are two waste products with potential for sustainable use in railway tracks.</div><div>While the previous studies have primarily focused on the benefits of utilizing steel slag as railway subballast, yet its suitability as railway ballast with and without tyre chips (TC) has not been comprehensively investigated. Moreover, the possible effect of coal fouling on the performance of TC-intermixed steel slag ballast is yet to be studied. Therefore, the current study assessed the influence of TC on the performance of slag-granite ballast mixture under coal-fouled condition using large-scale track simulation test (TST) and constant-head permeability apparatus. TST results indicated that vertical and lateral deformations of ballast increased, while the track stiffness (<em>k</em>) and ballast breakage index (<em>BBI</em>) decreased with the increase in proportion of tyre chips. The threshold content of tyre chips to be mixed with steel slag ballast (SSB) is identified as 10%. The study further established that the addition of coal leads to an increase in deformations, while reducing <em>BBI</em> of TC intermixed slag-granite ballast. Moreover, the addition of coal causes a significant reduction in hydraulic conductivity of the TC intermixed ballast. Further, the critical value of void contamination index is determined to be 25%.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101869"},"PeriodicalIF":5.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798796","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 : 2025-12-17DOI: 10.1016/j.trgeo.2025.101870
Liu Pan , Lei Xu , Yan Bin , Chen Mei
To address the challenges of complex modeling and low computational efficiency in the train-track-tunnel-soil (TTTS) system, this study develops a TTTS dynamic interaction model based on the spectral element method (SEM). To accurately described the complex geometry of the tunnel-soil system, this research employs iso-parameter hexahedral and triangular prism spectral elements to simulate the tunnel and surrounding soil, respectively, and describes the tunnel-soil interaction utilizing multiscale coupling method. Leveraging the low-frequency nature of infrastructure vibration, this study introduces Gaussian precise integration method, combined with multi-step hybrid solution, enables accurate resolution of infrastructure vibration with arbitrary integration step. The reliability of the proposed model and solution method is validated through comparison with the FEM model and general solution method. Subsequently, the aforementioned model is applied to the dynamic analysis of the TTTS system to investigate the ground vibration distribution induced by the train, and to examine the effects of the TTTS system parameters on the ground vibration in terms of time–frequency domain vibration and vibration level.
{"title":"A spectral element-based dynamic model for train-track-tunnel-soil interaction","authors":"Liu Pan , Lei Xu , Yan Bin , Chen Mei","doi":"10.1016/j.trgeo.2025.101870","DOIUrl":"10.1016/j.trgeo.2025.101870","url":null,"abstract":"<div><div>To address the challenges of complex modeling and low computational efficiency in the train-track-tunnel-soil (TTTS) system, this study develops a TTTS dynamic interaction model based on the spectral element method (SEM). To accurately described the complex geometry of the tunnel-soil system, this research employs <em>iso</em>-parameter hexahedral and triangular prism spectral elements to simulate the tunnel and surrounding soil, respectively, and describes the tunnel-soil interaction utilizing multiscale coupling method. Leveraging the low-frequency nature of infrastructure vibration, this study introduces Gaussian precise integration method, combined with multi-step hybrid solution, enables accurate resolution of infrastructure vibration with arbitrary integration step. The reliability of the proposed model and solution method is validated through comparison with the FEM model and general solution method. Subsequently, the aforementioned model is applied to the dynamic analysis of the TTTS system to investigate the ground vibration distribution induced by the train, and to examine the effects of the TTTS system parameters on the ground vibration in terms of time–frequency domain vibration and vibration level.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101870"},"PeriodicalIF":5.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841255","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 : 2025-12-17DOI: 10.1016/j.trgeo.2025.101863
Guoqing Cai , Xianfeng Diao , Yinghui Lv , Ning Li , Chao Hu
Currently, research on the erosion-induced deformation of interlayer soils under seepage action remains at the macroscopic level, with insufficient understanding of the underlying microscopic mechanisms behind the observed macroscopic deformations. Therefore, this study, based on a Computational Fluid Dynamic − Discrete Element Method (CFD-DEM) coupled method, investigates the macroscopic deformation process and the evolution of the microscopic contact mechanics of interlayer soils during seepage, considering the effects of different seepage directions and hydraulic gradients. The results show that, parallel seepage along the contact surface, due to the absence of a coarse particle layer as a barrier, results in greater particle loss and deeper impact. The migration of fine particles forms cavities, triggering slippage and settlement of the upper coarse particle layer. The contact forces around these cavities are weak and sparse, posing a risk for deformation and collapse of the structure. In the initial stage of seepage, the vertical contact forces weaken, promoting particle migration and causing settlement of the upper layers. Packing and clogging increase the contact forces, restricting the movement of fine particles, while the stress concentration that forms allow the coarse particles to provide stable support, leading to stabilization of the settlement. Seepage disrupts particle connectivity, causing an uneven distribution of contact forces. After the seepage ends, a stress redistribution occurs, and the collapse triggered by the cavities is more likely to cause overall structural changes, ultimately resulting in a significant anisotropic distribution of the contact forces.
{"title":"Erosion mechanism of interlayer soils under different seepage directions: a CFD-DEM perspective","authors":"Guoqing Cai , Xianfeng Diao , Yinghui Lv , Ning Li , Chao Hu","doi":"10.1016/j.trgeo.2025.101863","DOIUrl":"10.1016/j.trgeo.2025.101863","url":null,"abstract":"<div><div>Currently, research on the erosion-induced deformation of interlayer soils under seepage action remains at the macroscopic level, with insufficient understanding of the underlying microscopic mechanisms behind the observed macroscopic deformations. Therefore, this study, based on a Computational Fluid Dynamic − Discrete Element Method<!--> <!-->(CFD-DEM) coupled method, investigates the macroscopic deformation process and the evolution of the microscopic contact mechanics of interlayer soils during seepage, considering the effects of different seepage directions and hydraulic gradients. The results show that, parallel seepage along the contact surface, due to the absence of a coarse particle layer as a barrier, results in greater particle loss and deeper impact. The migration of fine particles forms cavities, triggering slippage and settlement of the upper coarse particle layer. The contact forces around these cavities are weak and sparse, posing a risk for deformation and collapse of the structure. In the initial stage of seepage, the vertical contact forces weaken, promoting particle migration and causing settlement of the upper layers. Packing and clogging increase the contact forces, restricting the movement of fine particles, while the stress concentration that forms allow the coarse particles to provide stable support, leading to stabilization of the settlement. Seepage disrupts particle connectivity, causing an uneven distribution of contact forces. After the seepage ends, a stress redistribution occurs, and the collapse triggered by the cavities is more likely to cause overall structural changes, ultimately resulting in a significant anisotropic distribution of the contact forces.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101863"},"PeriodicalIF":5.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841345","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 : 2025-12-17DOI: 10.1016/j.trgeo.2025.101865
Xuhao Cui , Yapeng Liu , Bowen Du , Hong Xiao , Hongbin Xu , Yang Wang , Yihao Chi
Tunnels in complex geological and high water pressure environments are prone to diseases such as tunnel floor heave (TFH), which seriously affects the operation and safety of high-speed railways. Water is a key contributing factor to TFH. By applying radial loads and constraint conditions to the tunnel base, the confining pressure effect caused by high water pressure and water-induced mudstone swelling on the tunnel base is simulated, and a tunnel base structure-load model is established. Furthermore, a refined finite element simulation analysis model considering the cohesive zone model and concrete damage plastic is developed to study the influences of different confining pressures, confining pressure ranges, and inverted arch thicknesses on the deformation, interlayer bonding, and interlayer gap of the track structure. The calculation results indicate that the maximum vertical deformation of the rail is positively correlated with the confining pressure and negatively correlated with the inverted arch thickness. The deformation range is closely related to the confining pressure range. The deformation reaches a maximum of 57.8 mm when the confining pressure is 2.0 MPa, the confining pressure range is 30 m, and the inverted arch thickness is 0.4 m. Bonding damage between the track slab and the backfill layer occurs at the boundary between the confining pressure zone and the non-confining pressure zone. The significant influence of insufficient inverted arch thickness on bond damage is not linear, the maximum bonding damage area increases from 45.5 m2 at a thickness of 0.78 m to 75.8 m2 at 0.5 m. The gaps between the backfill layer and the inverted arch are unevenly distributed laterally along the track, with the interlayer gaps curve transitioning from a “trapezoidal” shape on the outer rail side to an “M” shape on the inner rail side. The research results play an important role in the design and maintenance of ballastless tracks in tunnels under the action of TFH.
{"title":"The influence of tunnel floor heave induced by high water pressure on the mechanical response of ballastless track","authors":"Xuhao Cui , Yapeng Liu , Bowen Du , Hong Xiao , Hongbin Xu , Yang Wang , Yihao Chi","doi":"10.1016/j.trgeo.2025.101865","DOIUrl":"10.1016/j.trgeo.2025.101865","url":null,"abstract":"<div><div>Tunnels in complex geological and high water pressure environments are prone to diseases such as tunnel floor heave (TFH), which seriously affects the operation and safety of high-speed railways. Water is a key contributing factor to TFH. By applying radial loads and constraint conditions to the tunnel base, the confining pressure effect caused by high water pressure and water-induced mudstone swelling on the tunnel base is simulated, and a tunnel base structure-load model is established. Furthermore, a refined finite element simulation analysis model considering the cohesive zone model and concrete damage plastic is developed to study the influences of different confining pressures, confining pressure ranges, and inverted arch thicknesses on the deformation, interlayer bonding, and interlayer gap of the track structure. The calculation results indicate that the maximum vertical deformation of the rail is positively correlated with the confining pressure and negatively correlated with the inverted arch thickness. The deformation range is closely related to the confining pressure range. The deformation reaches a maximum of 57.8 mm when the confining pressure is 2.0 MPa, the confining pressure range is 30 m, and the inverted arch thickness is 0.4 m. Bonding damage between the track slab and the backfill layer occurs at the boundary between the confining pressure zone and the non-confining pressure zone. The significant influence of insufficient inverted arch thickness on bond damage is not linear, the maximum bonding damage area increases from 45.5 m<sup>2</sup> at a thickness of 0.78 m to 75.8 m<sup>2</sup> at 0.5 m. The gaps between the backfill layer and the inverted arch are unevenly distributed laterally along the track, with the interlayer gaps curve transitioning from a “trapezoidal” shape on the outer rail side to an “M” shape on the inner rail side. The research results play an important role in the design and maintenance of ballastless tracks in tunnels under the action of TFH.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101865"},"PeriodicalIF":5.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841298","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 : 2025-12-17DOI: 10.1016/j.trgeo.2025.101857
Haoran Fu , Guanwen Liang , Chengpeng Hong , Duanyang Zhuang , Ruitao Tang , Jianqun Jiang
Ensuring the structural integrity of heavy-haul railway fastening systems is critical for operational safety and derailment prevention. Conventional rigid sensors suffer from bulkiness, poor embeddability, and limited dynamic performance, hindering their use in this demanding application. This study introduces a novel piezoelectric material engineered with a unibody design, offering inherent advantages of lightweight construction, flexibility, and conformability for integration into fastening components. Finite element analysis and D33 coefficient testing demonstrated that this smart material achieves superior strain distribution uniformity and signal stability compared to traditional clipped PVDF sensors. A specialized stepwise polarization-edge depolarization process was developed to enhance piezoelectric polarization uniformity, thereby improving measurement accuracy. The smart PVDF material was rigorously calibrated using a high-frequency impact system, and its fatigue resistance and stiffness-sensing capability were evaluated across varying environmental conditions. Integrated directly into rubber pads within a full-scale heavy-haul railway subgrade physical model, the smart PVDF material effectively quantified the environmental stiffness of the fastening system – capturing its dynamic interaction with the rock ballast aggregate – under diverse operational conditions. Results revealed a distinct nonlinear decrease in environmental stiffness with increasing speed and load, contrasting with universal stiffness trends and highlighting the critical role of rock ballast aggregate behavior. This smart PVDF material demonstrates exceptional durability and adaptability for monitoring nonlinear environmental stiffness responses in heavy-haul railway infrastructure, enabling advanced assessment of rock ballast aggregate-fastening system interactions and providing a promising foundation for intelligent track health monitoring and early-warning systems.
{"title":"Ballast Aggregate Driven Nonlinear Environmental Stiffness in Heavy Haul Railway Fastenings: Novel Flexible Piezoelectric Sensor Monitoring","authors":"Haoran Fu , Guanwen Liang , Chengpeng Hong , Duanyang Zhuang , Ruitao Tang , Jianqun Jiang","doi":"10.1016/j.trgeo.2025.101857","DOIUrl":"10.1016/j.trgeo.2025.101857","url":null,"abstract":"<div><div>Ensuring the structural integrity of heavy-haul railway fastening systems is critical for operational safety and derailment prevention. Conventional rigid sensors suffer from bulkiness, poor embeddability, and limited dynamic performance, hindering their use in this demanding application. This study introduces a novel piezoelectric material engineered with a unibody design, offering inherent advantages of lightweight construction, flexibility, and conformability for integration into fastening components. Finite element analysis and D<sub>33</sub> coefficient testing demonstrated that this smart material achieves superior strain distribution uniformity and signal stability compared to traditional clipped PVDF sensors. A specialized stepwise polarization-edge depolarization process was developed to enhance piezoelectric polarization uniformity, thereby improving measurement accuracy. The smart PVDF material was rigorously calibrated using a high-frequency impact system, and its fatigue resistance and stiffness-sensing capability were evaluated across varying environmental conditions. Integrated directly into rubber pads within a full-scale heavy-haul railway subgrade physical model, the smart PVDF material effectively quantified the environmental stiffness of the fastening system – capturing its dynamic interaction with the rock ballast aggregate – under diverse operational conditions. Results revealed a distinct nonlinear decrease in environmental stiffness with increasing speed and load, contrasting with universal stiffness trends and highlighting the critical role of rock ballast aggregate behavior. This smart PVDF material demonstrates exceptional durability and adaptability for monitoring nonlinear environmental stiffness responses in heavy-haul railway infrastructure, enabling advanced assessment of rock ballast aggregate-fastening system interactions and providing a promising foundation for intelligent track health monitoring and early-warning systems.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101857"},"PeriodicalIF":5.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798691","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 : 2025-12-16DOI: 10.1016/j.trgeo.2025.101864
Jang-Un Kim, Hyunwook Choo
Many structures built on saturated clays are subjected to repetitive loads from sources such as waves, wind, and traffic. This loading can induce excess pore water pressure within saturated clays, leading to additional volumetric deformation and the long-term degradation of geostructures. This study investigated the compressibility of saturated clays under repetitive loading, focusing on the coupled effects of the initial degree of consolidation (Ui) and loading frequency (f). A newly developed loading system was used to perform tests on sand, kaolin, and Ca-bentonite specimens across a wide range of frequencies (f = 0.011, 0.046, 0.139, 0.278, 1.67, 8.33, 25, 125, and 250 mHz) and consolidation states (Ui = 0, 0.2, 0.4, 0.6, and 1.0). The results indicated that the cyclic-induced void ratio change (Δe) was highly sensitive to both Ui and f. For underconsolidated soils (Ui < 1), high-frequency loading significantly increased Δe, whereas the response was minimal and largely independent of these factors under low-frequency conditions or for normally consolidated soils (Ui = 1). This study identified three distinct drainage regimes: drained, partially drained, and undrained based on the cyclic loading ratio (T/t100), establishing a quantitative threshold of T/t100 ≤ 0.001 − 0.01 for the transition to pseudo-undrained behavior. Furthermore, repetitive loading was found to increase the horizontal effective stress, leading to a higher overconsolidation ratio and a corresponding reduction in post-cyclic compressibility. The findings provide new experimental evidence on the complex, coupled behaviors of saturated soils and offer critical insights for the reliable design and performance assessment of structures on soft clay deposits.
{"title":"Compressibility of Clays under Repetitive Loading: A New Perspective on Consolidation State, Loading Frequency, and Partially Drained Conditions","authors":"Jang-Un Kim, Hyunwook Choo","doi":"10.1016/j.trgeo.2025.101864","DOIUrl":"10.1016/j.trgeo.2025.101864","url":null,"abstract":"<div><div>Many structures built on saturated clays are subjected to repetitive loads from sources such as waves, wind, and traffic. This loading can induce excess pore water pressure within saturated clays, leading to additional volumetric deformation and the long-term degradation of geostructures. This study investigated the compressibility of saturated clays under repetitive loading, focusing on the coupled effects of the initial degree of consolidation (<em>U<sub>i</sub></em>) and loading frequency (<em>f</em>). A newly developed loading system was used to perform tests on sand, kaolin, and Ca-bentonite specimens across a wide range of frequencies (<em>f</em> = 0.011, 0.046, 0.139, 0.278, 1.67, 8.33, 25, 125, and 250 mHz) and consolidation states (<em>U<sub>i</sub></em> = 0, 0.2, 0.4, 0.6, and 1.0). The results indicated that the cyclic-induced void ratio change (Δ<em>e</em>) was highly sensitive to both <em>U<sub>i</sub></em> and <em>f</em>. For underconsolidated soils (<em>U<sub>i</sub></em> < 1), high-frequency loading significantly increased Δ<em>e</em>, whereas the response was minimal and largely independent of these factors under low-frequency conditions or for normally consolidated soils (<em>U<sub>i</sub></em> = 1). This study identified three distinct drainage regimes: drained, partially drained, and undrained based on the cyclic loading ratio (<em>T</em>/<em>t<sub>100</sub></em>), establishing a quantitative threshold of <em>T</em>/<em>t<sub>100</sub></em> ≤ 0.001 − 0.01 for the transition to pseudo-undrained behavior. Furthermore, repetitive loading was found to increase the horizontal effective stress, leading to a higher overconsolidation ratio and a corresponding reduction in post-cyclic compressibility. The findings provide new experimental evidence on the complex, coupled behaviors of saturated soils and offer critical insights for the reliable design and performance assessment of structures on soft clay deposits.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101864"},"PeriodicalIF":5.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841258","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 : 2025-12-16DOI: 10.1016/j.trgeo.2025.101858
Xuefei Wang , Xu Liu , Jiale Li , Jianmin Zhang , Guowei Ma
Intelligent Compaction (IC) relies on high-quality datasets for accurate quality evaluation. However, the absence of sufficient field data challenges the model development. This study proposes a similarity model based on coordinated laboratory and field tests, aiming to provide theoretical basis for the dataset expansion. A spatio-temporal equivalence model is established using the dual energy-state equivalence principle to correlate the laboratory compaction time and the number of rolling passes. Multi-domain ICMVs are used to validate the similarity model quantitatively. Results show that the proposed method effectively expands the IC dataset. A compaction quality evaluation model trained on the augmented dataset shows significantly reduced prediction error and improved generalization comparing to the original model for all evaluation indexes. This work provides a theoretical basis to adopt the laboratory test to field applications, enhancing the assessment reliability of IC.
{"title":"A similarity model for subgrade compaction from collaborative laboratory-field tests","authors":"Xuefei Wang , Xu Liu , Jiale Li , Jianmin Zhang , Guowei Ma","doi":"10.1016/j.trgeo.2025.101858","DOIUrl":"10.1016/j.trgeo.2025.101858","url":null,"abstract":"<div><div>Intelligent Compaction (IC) relies on high-quality datasets for accurate quality evaluation. However, the absence of sufficient field data challenges the model development. This study proposes a similarity model based on coordinated laboratory and field tests, aiming to provide theoretical basis for the dataset expansion. A spatio-temporal equivalence model is established using the dual energy-state equivalence principle to correlate the laboratory compaction time and the number of rolling passes. Multi-domain ICMVs are used to validate the similarity model quantitatively. Results show that the proposed method effectively expands the IC dataset. A compaction quality evaluation model trained on the augmented dataset shows significantly reduced prediction error and improved generalization comparing to the original model for all evaluation indexes. This work provides a theoretical basis to adopt the laboratory test to field applications, enhancing the assessment reliability of IC.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101858"},"PeriodicalIF":5.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798765","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 : 2025-12-16DOI: 10.1016/j.trgeo.2025.101855
Zhi Ding , Jiao-Ming Xu , Yang Chen , Shao-Heng He
The free gas reservoirs occurring in the form of sacs are widely distributed along the southeastern coastal region of China, potentially posing significant risks during shield tunnelling. Hence, investigating the deformative mechanism of gas-bearing soils induced by shield excavation holds vital engineering significance. In this paper, physical model tests simulating gas-bearing strata were performed under varying L/D values (the ratio of the distance between shield excavation face and the sac to the tunnel diameter), with dry sand strata set as a control. The images captured during the tests were processed through PIV (Particle Image Velocimetry) analysis. It can be found that the variation regarding support pressure and pore pressure of fluid sac was primarily demarcated by the limiting state of the excavation, exhibiting two distinct phases in each test. Face instability occurred more rapidly in gas-bearing strata, the failure area evolved from an initial configuration of a “triangle and rectangle” to a final distribution resembling two interrelated trapezoids. The curves of surface settlement progressively exhibit a characteristic of groove shape as the displacement of tunnel face increased, and oblique photogrammetry technique was then adopted in this study to achieve three-dimensional reconstruction of the settlement pit. For a larger value of L/D, the influencing area induced by shield excavation varies within a broader range while the maximum deformation and volume is relatively small. By improving column hole shrinkage theory, a theoretical formulation accounting for soil loss was derived to accurately predict surface deformation in gas-bearing strata. On this basis, the effects of tunnel depth and excavation radius on surface deformation were analysed.
{"title":"Experimental and theoretical study on the shield tunneling model for gas-bearing strata based on image processing","authors":"Zhi Ding , Jiao-Ming Xu , Yang Chen , Shao-Heng He","doi":"10.1016/j.trgeo.2025.101855","DOIUrl":"10.1016/j.trgeo.2025.101855","url":null,"abstract":"<div><div>The free gas reservoirs occurring in the form of sacs are widely distributed along the southeastern coastal region of China, potentially posing significant risks during shield tunnelling. Hence, investigating the deformative mechanism of gas-bearing soils induced by shield excavation holds vital engineering significance. In this paper, physical model tests simulating gas-bearing strata were performed under varying <em>L</em>/<em>D</em> values (the ratio of the distance between shield excavation face and the sac to the tunnel diameter), with dry sand strata set as a control. The images captured during the tests were processed through PIV (Particle Image Velocimetry) analysis. It can be found that the variation regarding support pressure and pore pressure of fluid sac was primarily demarcated by the limiting state of the excavation, exhibiting two distinct phases in each test. Face instability occurred more rapidly in gas-bearing strata, the failure area evolved from an initial configuration of a “triangle and rectangle” to a final distribution resembling two interrelated trapezoids. The curves of surface settlement progressively exhibit a characteristic of groove shape as the displacement of tunnel face increased, and oblique photogrammetry technique was then adopted in this study to achieve three-dimensional reconstruction of the settlement pit. For a larger value of <em>L</em>/<em>D</em>, the influencing area induced by shield excavation varies within a broader range while the maximum deformation and volume is relatively small. By improving column hole shrinkage theory, a theoretical formulation accounting for soil loss was derived to accurately predict surface deformation in gas-bearing strata. On this basis, the effects of tunnel depth and excavation radius on surface deformation were analysed.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101855"},"PeriodicalIF":5.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798801","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 : 2025-12-16DOI: 10.1016/j.trgeo.2025.101859
Xuming Li , Ying Chen , Wenjun Luo , Wenjie Guo , Chao Zou
Train-induced vibrations in metro depot turnout areas present critical challenges for over-track building developments, significantly impacting human comfort and vibration-sensitive equipment through elevated environmental pollution levels. To address this, propose an integrated two-stage simulation framework combining high-fidelity train-track-turnout dynamics with soil-building wave propagation modeling. A train-track dynamic model incorporating the turnout structure was developed to calculate the wheel-rail interaction forces, which serve as input for the subsequent track-soil-building model. The track-soil-building system was established using a combined finite element and infinite element method to simulate ground-borne vibrations and the associated structural responses effectively. Field validation demonstrates exceptional accuracy, with simulated 1/3-octave band acceleration levels showing a good agreement with measurements across 4–80 Hz frequencies. Key findings reveal that turnout areas generate wide-spectrum vibrations from combined impacts at switch and crossing panels, exhibiting distinctive propagation characteristics. High-frequency components attenuate rapidly while low-frequency energy propagates extensively with minimal loss. Critically, building responses show resonance-driven amplification at 10–20 Hz frequencies due to soil-structure interaction, necessitating targeted vibration control in turnout areas to mitigate structural vibration risks. This research establishes a validated methodology for predicting turnout-induced building vibrations, providing essential data for optimizing metro depot designs.
{"title":"Characteristics and prediction of over-track building vibration response due to train operation in turnout areas","authors":"Xuming Li , Ying Chen , Wenjun Luo , Wenjie Guo , Chao Zou","doi":"10.1016/j.trgeo.2025.101859","DOIUrl":"10.1016/j.trgeo.2025.101859","url":null,"abstract":"<div><div>Train-induced vibrations in metro depot turnout areas present critical challenges for over-track building developments, significantly impacting human comfort and vibration-sensitive equipment through elevated environmental pollution levels. To address this, propose an integrated two-stage simulation framework combining high-fidelity train-track-turnout dynamics with soil-building wave propagation modeling. A train-track dynamic model incorporating the turnout structure was developed to calculate the wheel-rail interaction forces, which serve as input for the subsequent track-soil-building model. The track-soil-building system was established using a combined finite element and infinite element method to simulate ground-borne vibrations and the associated structural responses effectively. Field validation demonstrates exceptional accuracy, with simulated 1/3-octave band acceleration levels showing a good agreement with measurements across 4–80 Hz frequencies. Key findings reveal that turnout areas generate wide-spectrum vibrations from combined impacts at switch and crossing panels, exhibiting distinctive propagation characteristics. High-frequency components attenuate rapidly while low-frequency energy propagates extensively with minimal loss. Critically, building responses show resonance-driven amplification at 10–20 Hz frequencies due to soil-structure interaction, necessitating targeted vibration control in turnout areas to mitigate structural vibration risks. This research establishes a validated methodology for predicting turnout-induced building vibrations, providing essential data for optimizing metro depot designs.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101859"},"PeriodicalIF":5.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798804","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 : 2025-12-16DOI: 10.1016/j.trgeo.2025.101861
Ming Dai , Kaichao Wang , Junhua Xiao , Quanmei Gong , Hongye Yan
Red-stratum mudstone, due to its wide distribution and convenient availability, has been widely used in high-fill subgrade projects in western China, but its low strength and susceptibility to fracturing make the problem of creep deformation particularly prominent. In this paper, a series of triaxial creep tests on red-stratum mudstone soil-rock mixture were carried out, focusing on the influence of rock content and stress state on creep behaviors. The development of axial and volumetric creep strains, the effect of rock content on the viscoplastic flow direction was clarified, and the time-dependent evolution of particle breakage was further analyzed. The results show that creep strain develops rapidly in the initial stage, then gradually slows down and tends to stabilize, and the overall curve exhibits a hyperbolic feature. At the same time, the final axial creep strain decreases first and then increases with the increase of rock content, with the optimal range being 0.5–0.7. Moreover, the volumetric creep path differs significantly from the conventional shear path, meaning the traditional dilatancy equation cannot directly describe the viscoplastic flow direction. Finally, particle sieve tests reveal that creep behaviors depend not only on particle breakage but also on the internal pore structure of the mixture. A denser pore structure will weaken the contribution of particle breakage to macroscopic creep deformation.
{"title":"Investigation on the triaxial creep behavior of red-stratum mudstone soil-rock mixture with different rock contents","authors":"Ming Dai , Kaichao Wang , Junhua Xiao , Quanmei Gong , Hongye Yan","doi":"10.1016/j.trgeo.2025.101861","DOIUrl":"10.1016/j.trgeo.2025.101861","url":null,"abstract":"<div><div>Red-stratum mudstone, due to its wide distribution and convenient availability, has been widely used in high-fill subgrade projects in western China, but its low strength and susceptibility to fracturing make the problem of creep deformation particularly prominent. In this paper, a series of triaxial creep tests on red-stratum mudstone soil-rock mixture were carried out, focusing on the influence of rock content and stress state on creep behaviors. The development of axial and volumetric creep strains, the effect of rock content on the viscoplastic flow direction was clarified, and the time-dependent evolution of particle breakage was further analyzed. The results show that creep strain develops rapidly in the initial stage, then gradually slows down and tends to stabilize, and the overall curve exhibits a hyperbolic feature. At the same time, the final axial creep strain decreases first and then increases with the increase of rock content, with the optimal range being 0.5–0.7. Moreover, the volumetric creep path differs significantly from the conventional shear path, meaning the traditional dilatancy equation cannot directly describe the viscoplastic flow direction. Finally, particle sieve tests reveal that creep behaviors depend not only on particle breakage but also on the internal pore structure of the mixture. A denser pore structure will weaken the contribution of particle breakage to macroscopic creep deformation.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"57 ","pages":"Article 101861"},"PeriodicalIF":5.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841297","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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