Transportation Geotechnics最新文献

{"title":"Estimating the compacted dry density of gravelly soil with oversized particles","authors":"","doi":"10.1016/j.trgeo.2024.101379","DOIUrl":"10.1016/j.trgeo.2024.101379","url":null,"abstract":"<div><div>The compacted dry density of gravelly soils containing particles that are too large for ordinary laboratory compaction tests is usually estimated by measuring the dry density of the base sample obtained by removing over-sized particles then correcting the measured value by the Walker-Holtz Equation (W&amp;H Eq.). It is known that the W&amp;H Eq. overestimates the dry density of gravelly soils and this trend becomes stronger as the mass ratio <em>P</em> of oversized particles increases. It seems that a satisfactory solution is not yet available. A comprehensive series of laboratory compaction tests was performed on a wide variety of gravelly soil samples with different particle sizes, grading uniformities and particle shapes. The followings were found. The ratio, <em>X</em>, of the maximum dry density predicted by the W&amp;H Eq. to the measured value increases linearly from unity as <em>P</em> increases from zero up to approximately 0.75. The slope of the <em>X</em>-<em>P</em> relation, (<em>X</em> − 1.0) / <em>P</em>, increases as the coefficient of uniformity or the fines content of the base sample increases and as the gravel particles become more angular in a synergistic manner. It is proposed to estimate the maximum dry density of compacted gravelly soil containing oversized particles by dividing the value predicted from the W&amp;H Eq. by <em>X</em> obtained from the substitution of <em>P</em> into the relevant <em>X</em>-<em>P</em> relation. Proposed based on the above is an effective and efficient compaction method for gravelly soils containing oversized particles that controls the degree of saturation and the compaction energy.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on damage characteristics and contact interface evolution behavior of double-block ballastless track considering tunnel floor heave","authors":"","doi":"10.1016/j.trgeo.2024.101389","DOIUrl":"10.1016/j.trgeo.2024.101389","url":null,"abstract":"<div><div>Excessive railway tunnel floor heave (TFH) will reduce the durability of the track structure and jeopardize train operation safety. The TFH characteristics were fitted into cosine and bilinear curves according to the monitoring data. A nonlinear failure analysis model of double-block ballastless track under TFH was established. The deformation transfer law, structural damage mechanism and the interlayer bonding interface failure evolution of the track structure under different TFH characteristics were explored. The results show that the deformation of TFH can be well mapped to the track. The amplitude transfer ratio is less than 100 %. The maximum wavelength transfer ratio under the cosine and bilinear TFH is 129.3 % and 127.5 %, respectively. To avoid the damage of track structure, when the wavelength is 10 m, the amplitude of cosine and bilinear TFH should be controlled at 2.5 mm and 0.5 mm respectively. When the wavelength is greater than 10 m, the amplitude can be appropriately increased. To avoid interlayer bonding cracking, the cosine and bilinear amplitudes with a wavelength of 10 m should be controlled at 5 mm and 1.5 mm, respectively. The track-tunnel interlayer debonding failure under the cosine curve occurs at the edge of the TFH, while the bilinear curve occurs at the center and edge of the TFH. The gaps under the cosine and bilinear TFH exhibit double-peak and multi-peak shapes, respectively. This study can provide theoretical guidance for controlling the performance degradation of track structure caused by TFH.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing fragmentation and potential sliding zones in rock tunnels via computer vision technology","authors":"","doi":"10.1016/j.trgeo.2024.101384","DOIUrl":"10.1016/j.trgeo.2024.101384","url":null,"abstract":"<div><div>During the excavation of rock tunnels, accurately understanding the structural characteristics of the tunnel face is crucial for ensuring construction safety. The study evaluates the structural characteristics of the tunnel face by precisely characterizing and analyzing parameters like fracture trace length and dip angle, aiming to calculate the degree of fragmentation and potential sliding zones of the rock mass. In evaluating rock fragmentation degree, the study identifies and quantifies fracture trace lengths as a single-factor indicator to assess the fragmentation of the rock mass on the working face. By comparing with the p21 index, the reliability and reasonableness of the rock fragmentation evaluation are discussed. For the evaluation of potential sliding zones, a method for approximating the extraction of fracture traces is proposed. The assessment is then conducted based on multi-factor indicators, including fracture dip angle and length. Additionally, the advantages and disadvantages of various indicators under different calculation methods are discussed. The study finds that rock fragmentation indicators offer a more detailed and accurate description of the actual fracture density of the rock mass compared to the P21 index, proving to be generally more reliable under extreme conditions. Furthermore, the evaluation of rock fragmentation and potential sliding zones on the rock face can provide important references for the refined extraction of rock mass structural characteristics, ensuring the safe construction of tunnels.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tunnelling-induced nonlinear responses of continuous pipelines resting on tensionless Winkler foundation","authors":"","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":null,"pages":null},"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}

{"title":"Risk-based probabilistic assessment of a bridge collapse due to abutments scour. A case study","authors":"","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":null,"pages":null},"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}

{"title":"Experimental investigation and modelling of the mechanical behaviors of fine/coarse soil mixture","authors":"","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>_d-f, while independent of the coarse grain content <em>f</em>_v; (ii) two various fabrics of mixture were distinguished by a characteristic <em>f</em>_v-cha value: a fine matrix macrostructure when <em>f</em>_v &lt; <em>f</em>_v-cha and a coarse grain dominated fabric when <em>f</em>_v &gt; <em>f</em>_v-cha; (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>_r due to the decline of suction <span><math><mi>ψ</mi></math></span>, but the growth of damping ratio <em>D</em>_r 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>_d and <em>f</em>_v to be considered. A constitutive model was also proposed for the <em>M</em>_r, taking the influences of <em>σ</em>_d,<span><math><mi>ψ</mi></math></span> and <em>f</em>_v into account.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"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}

{"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":"","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":null,"pages":null},"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}

{"title":"Centrifuge tests study on settlement and damage modes of bridge approaches using deep-seated slab","authors":"","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":null,"pages":null},"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}

{"title":"A simple model incorporating foam rheology to quantify foam penetration behaviour in EPB shield tunnelling","authors":"","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>₁₀) 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":null,"pages":null},"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}

{"title":"Railway Track Deterioration Models: A Review of the State of the Art","authors":"","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":null,"pages":null},"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}