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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Mechanism of Pipeline-Induced Road Collapse under Low Groundwater Levels: Insights from Erosion Dynamics and Engineering Implications</title>
      <link>https://trid.trb.org/View/2681255</link>
      <description><![CDATA[Urban road collapses cause substantial economic losses and social disruption while directly compromising the integrity of underlying pipeline networks. Despite extensive research on failures stemming from underground water seepage following pipeline damage, the collapse mechanisms triggered when groundwater levels fall below the pipeline burial depth remain insufficiently understood. This study employs a combined approach of laboratory model experiments and software simulations to systematically investigate water flow–induced soil erosion and its impact on road collapse following pipeline damage. The results demonstrated that under low-groundwater conditions, the extent of erosion into the pipeline correlates positively with soil permeability. Moreover, the formation and lateral expansion of cavities—observed even at small scales—indicate an urgent need to extend monitoring zones and implement reinforcement strategies over wider areas. In scenarios with low soil permeability, vortex formation inside pipelines leads to elevated wall pressures, further underscoring the importance of proactive surveillance of adjacent pipeline segments, particularly during periods of reduced water supply. These findings not only advance the theoretical understanding of erosion mechanisms but also provide a rigorous foundation for developing risk-based maintenance and preemptive measures to enhance pipeline system integrity.]]></description>
      <pubDate>Thu, 25 Jun 2026 09:40:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2681255</guid>
    </item>
    <item>
      <title>Numerical Analysis of Rainfall-Induced Landslides and Stability Assessment Along the Bonga-Mizan Road Section, Ethiopia</title>
      <link>https://trid.trb.org/View/2717186</link>
      <description><![CDATA[Landslides along the Bonga-Mizan road segment in Ethiopia have been persistent despite previous mitigation measures, disrupting socioeconomic activities and increasing maintenance costs. This study aims to investigate the underlying factors contributing to the recurrent landslides and identify practical mitigation strategies. While factors such as rainfall, groundwater, material properties, geology, and topography have been acknowledged in prior studies, the specific impact of rainfall and groundwater on slope stability remains underexplored, particularly in this region. The research evaluates the behavior and stability of slopes at two critical locations: stations 4 + 400 and 197 + 216 km. The findings reveal that rainfall and groundwater significantly reduce the factor of safety (FOS) and increase deformation, with FOS values decreasing from 1.53 to 2.04 under dry conditions to 0.98 and 0.91 under wet conditions, respectively. Deformation patterns and critical slip surfaces at depths of 11 and 10 m were also observed. These results underscore the dominant role of water-related factors in triggering landslide instability. The study suggests that enhanced drainage systems, including both groundwater and surface management, are essential for mitigating landslide risks in the area. The findings offer valuable insights to improve the resilience of road infrastructure in landslide-prone regions, thereby contributing to more effective disaster management and road maintenance strategies.]]></description>
      <pubDate>Wed, 24 Jun 2026 11:29:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2717186</guid>
    </item>
    <item>
      <title>A new ground freezing method using freezing tunnel segment for tunneling construction: A case study in Tianjin, China</title>
      <link>https://trid.trb.org/View/2682011</link>
      <description><![CDATA[The reception of tunneling shields is a critical stage in shield tunnel construction, during which the portal of the receiving shaft is broken, and the shield machine enters the shaft. In this process, groundwater and soil may gush into the receiving shaft and cause engineering accident. Conventional shield arrival technologies such as soil reinforcement and often struggle to effectively seal seepage pathways within the excavation gaps at the portal zone. This paper proposes a new ground-freezing method adopting an innovative ‘Freezing Tunnel Segment’ (FTS) aiming at effectively mitigating ground water leakage in the tunnel portal. The FTS is a new type of tunnel segment with built-in freezing tubes that can flexibly and precisely freeze the surrounding soil. This allows the formation of a frozen wall within the excavation gap and enhances the seepage plugging, effectively blocking groundwater inflow into the tunnel portal. In this study, the designment of the FTS is introduced in detail and a freezing experiment on a single FTS block is presented. Furthermore, the engineering case study using FTS enhanced ground freezing system for tunnel reception in Tianjin, China is investigated. The freezing experiment indicates that the frozen wall generated by FTS extended radially at a rate of about 6 mm/h. On-site monitoring from the practical engineering shows that the frozen wall reached a temperature of −12 °C with a thickness of 150 mm and achieved closure within 25 h. The proposed FTS enables precise and flexible ground freezing in tunnel construction under challenging hydrogeological conditions. Also, it provides an alternative to conventional AGF systems that generally employ external freezing tubes and involve a complex and time-consuming on-site construction process.]]></description>
      <pubDate>Thu, 18 Jun 2026 16:35:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2682011</guid>
    </item>
    <item>
      <title>Case study on the uplift of tunnel segments due to grouting layer deterioration during shield tunnel operation in karst fissure development strata</title>
      <link>https://trid.trb.org/View/2710450</link>
      <description><![CDATA[This study investigates the causes and impacts of shield tunnel segment uplift, particularly in karst fissure strata, where groundwater changes and geological conditions are often overlooked. Through a case study and 3D finite difference modeling, it was found that deterioration of the grouting layer, exacerbated by train vibrations and groundwater erosion, forms cavities that reduce surrounding rock confinement, leading to segment uplift and elliptical deformation. This deformation increases bending moments, decreases axial force, and worsens joint misalignment and leakage. The research highlights the critical role of grouting layer integrity in preventing uplift and provides practical insights for design, construction, and maintenance to mitigate structural risks in tunnel engineering.]]></description>
      <pubDate>Wed, 17 Jun 2026 16:14:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2710450</guid>
    </item>
    <item>
      <title>Hydromechanical Response of Deep Metro Station Excavations in Multistrata Soil to Rainfall Infiltration</title>
      <link>https://trid.trb.org/View/2705369</link>
      <description><![CDATA[The increasing frequency of heavy rainfall due to climate change raises concerns about the resilience of underground infrastructure during deep excavations. This study investigates the effects of rainfall infiltration on metro station excavations using a coupled hydromechanical finite-element model, with the Xipu Road Station in Hangzhou, China, as a case study. Simulation results show that rainfall infiltration causes a rapid rise in groundwater level. At low rainfall intensities, the rise is uneven because shearing near the wall reduces the soil void ratio and permeability. At higher intensities, the groundwater level rises more quickly and uniformly due to vertical infiltration combined with lateral seepage from zones with higher void ratios toward the wall. Rainfall also affects wall deformation. In unsupported excavations, wall deflection after rainfall is more than twice that measured before rainfall. In strutted systems, deflection remains nearly constant between struts but increases below the lowest strut, reaching a maximum near the excavation base. Strut forces increase after rainfall, particularly where strut spacing is large, with load increases ranging from 29% to 90% across excavation stages. Rainfall causes greater wall deflection than widening the excavation by 4 m. In contrast, increasing diaphragm-wall thickness from 0.8 to 1.2 m reduces deflection by about 30%, demonstrating the effectiveness of wall stiffness in limiting rainfall effects. These findings provide important insights for improving the safety and resilience of deep excavations under increasing rainfall conditions associated with climate change.]]></description>
      <pubDate>Thu, 04 Jun 2026 15:13:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2705369</guid>
    </item>
    <item>
      <title>Simulating Water Balance of Road Embankment Lysimeters</title>
      <link>https://trid.trb.org/View/2113189</link>
      <description><![CDATA[An alternative to dumping mineral materials containing moderate amounts of contaminants into landfills is to reuse them in road embankments and noise protection barriers. To ensure groundwater protection, seepage of precipitation water through these materials must be omitted or reduced to a minimum. Embankments consisting of both cohesive and coarse-grained soil materials under various designs of cover layers were investigated within six field lysimeters. To gain the understanding of the water balance, quantities of seepage water, as well as runoff in the cover layers and on the surface were monitored. When using moderately contaminated materials in earthworks, reliable prediction of the water balance is crucial. Thus, in this study 2.5 years of the lysimeter experiments were modeled using the finite element software Vadose/W. Results were compared to the experimental data. The unsaturated hydraulic characteristics of the core materials were known from experimental investigations. Those of the topsoil and the shoulder material were estimated from databases of similar soils. A climate boundary condition represented the daily mean of the actual climate data on-site including road runoff. The modeled water balances were in good agreement with the field data for the cohesive core material of low permeability. However, a tendency to overestimate of seepage water was observed, which was even higher in the lysimeters with coarse-grained materials. This is linked to the water-permeability of the shoulder material and demonstrates that the cover layers have a major influence on the water balance of the whole embankment.]]></description>
      <pubDate>Thu, 28 May 2026 17:09:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/2113189</guid>
    </item>
    <item>
      <title>A new method for anti-floating of underground structures: experimental study on active–passive combined anti-floating</title>
      <link>https://trid.trb.org/View/2670261</link>
      <description><![CDATA[With underground engineering “marching deep into the earth”, where hydrogeological conditions are highly complex, it is necessary to design effective anti-floating measures when constructing underground structures. First, an active–passive combined anti-floating test system for underground structures is independently designed and developed. Then, active–passive combined anti-floating tests are conducted under different basal water pressures and pressure-limiting heads by effectively combining active anti-floating through pressure-limiting drainage with passive anti-floating based on dead weight. Next, the drainage-to-shear strength ratio and the load-sharing ratio in active–passive anti-floating are determined. Finally, the test model is programmed using COMSOL Multiphysics, corroborating its rationality, and the effects of anti-floating measures for underground structures on pore pressure and flow rate in foundation clay are analyzed. Based on the results of this study, active pressure-limiting drainage in the developed test system effectively reduces the water pressure at the bottom of underground structures. When an underground structure is subjected to the same water buoyancy, the smaller the pressure-limiting head, the greater the ratio of water buoyancy borne by active anti-floating measures, and the greater the drainage-to-shear strength ratio and active/passive force ratio of the structure. When the total buoyancy borne by the underground structure increases, the drainage-to-shear strength ratio and active/passive force ratio of the model barrel increase gradually. Furthermore, the simulation results reveal the distribution characteristics of soil pore pressure and flow rate for the active–passive combined anti-floating measures, and provide a reference for the anti-floating design of underground engineering.]]></description>
      <pubDate>Wed, 13 May 2026 09:33:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2670261</guid>
    </item>
    <item>
      <title>Stability of the Tunnel Face Under the Seepage Conditions of Confined Water Strata</title>
      <link>https://trid.trb.org/View/2688835</link>
      <description><![CDATA[Numerical simulations investigated the hydraulic head distribution ahead of a tunnel face within a confined aquifer. An analytical function was derived to characterize this seepage field. This hydraulic head distribution was incorporated into a three-dimensional rotational failure mechanism to develop an upper-bound limit analysis model for assessing tunnel face stability under confined groundwater conditions. The model was validated against numerical results and existing analytical solutions. A parametric study demonstrated that confined aquifers considerably enlarged the failure zone. The critical face pressure increased linearly with higher groundwater levels. The position of impermeable layers relative to the aquifer critically influenced the failure mechanism. With an overlying aquiclude, a sharp transition at the interface locally reduced instability. Conversely, when the impermeable layer underlay the aquifer, the failure region extended in both height and length, significantly increasing collapse risk. Numerical simulations investigated the hydraulic head distribution ahead of a tunnel face within a confined aquifer. An analytical function was derived to characterize this seepage field. This hydraulic head distribution was incorporated into a three-dimensional rotational failure mechanism to develop an upper-bound limit analysis model for assessing tunnel face stability under confined groundwater conditions. The model was validated against numerical results and existing analytical solutions. A parametric study demonstrated that confined aquifers considerably enlarged the failure zone. The critical face pressure increased linearly with higher groundwater levels. The position of impermeable layers relative to the aquifer critically influenced the failure mechanism. With an overlying aquiclude, a sharp transition at the interface locally reduced instability. Conversely, when the impermeable layer underlay the aquifer, the failure region extended in both height and length, significantly increasing collapse risk.]]></description>
      <pubDate>Wed, 29 Apr 2026 09:09:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2688835</guid>
    </item>
    <item>
      <title>Response of Piled-Raft Foundation in Soft Soils under Groundwater Drawdown</title>
      <link>https://trid.trb.org/View/2688589</link>
      <description><![CDATA[An integrated analytical framework was developed to evaluate the time-dependent response of piled raft foundations (PRFs) subjected to groundwater drawdown. The formulation coupled Neuman’s transient well drawdown, axial pile load transfer, and raft–pile–soil interaction using Modified Mindlin’s theory to predict settlement, drag load development, neutral-plane depth, and time-dependent axial load redistribution. Validation against field data, centrifuge and numerical results showed good agreement. Parametric analyses quantified the effects of pumping rate, aquifer properties, hydraulic conductivity, radial distance from the drawdown source, and pile–soil relative stiffness on PRF performance. Results showed that pumping rate, vertical hydraulic conductivity, initial groundwater depth and pile–soil relative stiffness are the primary factors on settlement magnitude. Increasing the pumping rate produced more than a twofold increase in settlement. Higher hydraulic conductivity reduced settlement by approximately 80%. Deeper initial groundwater levels reduced settlement by more than 50%. Pile–soil relative stiffness strongly influenced time-dependent deformation. Specific yield and specific storage exerted a secondary influence. Negative skin friction governed the majority of axial loads and increased pile-head loads to 2.4 times the initial structural load. The framework provided a robust predictive tool for assessing the time-dependent settlement and load redistribution in PRFs during drawdown.]]></description>
      <pubDate>Wed, 29 Apr 2026 09:09:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2688589</guid>
    </item>
    <item>
      <title>Analysis of the Mechanical Properties of Central Columns in the Subway Station in Response to Groundwater Level Rise</title>
      <link>https://trid.trb.org/View/2632988</link>
      <description><![CDATA[Shallow underground excavation techniques are widely employed in urban subway construction, and the pile–beam–arch (PBA) method is especially prevalent in subway stations’ construction. This method is primarily designed to address the challenges posed by complex geological conditions, dense underground utilities and the proximity of existing structures encountered during the comprehensive development process of urban subterranean environments. This research focuses on the Workers’ Stadium Station of Beijing Metro Line 17, utilizing MIDAS GTS NX computational simulation software to simulate the stratigraphic structure and construction processes associated with the station. A comparative analysis is conducted between the numerical simulation results and the corresponding field-measured data. By fitting the numerical simulation results and field-measured data with a Gaussian function, the coefficient of determination (R2) is determined to be 0.9723. This indicates an excellent agreement between the axial forces sustained by the CFST column in the model and the field-measured data across various excavation stages of the PBA method. This suggests that the numerical modeling effectively reflects the impact of actual construction activities on the CFST columns. Additionally, building upon this model and integrating principles from elastic mechanics theory, the paper investigates the impact of rising groundwater levels on the central column of the station during its operational phase. The analysis reveals that as the groundwater levels rise, both the central column’s axial force and axial displacement exhibit a gradual upward trend, with the rate of increase initially rising before subsequently declining. Notably, when the groundwater level reaches the top slab of the station, both parameters attain their maximum values. This research contributes to understanding the implications of groundwater level fluctuations on the stability of subway stations and offers recommendations for the ongoing operation of such facilities.]]></description>
      <pubDate>Mon, 27 Apr 2026 16:19:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2632988</guid>
    </item>
    <item>
      <title>Collapse deformation characteristics and computational model for loess sites under bottom-up field immersion</title>
      <link>https://trid.trb.org/View/2653173</link>
      <description><![CDATA[Groundwater level fluctuation-induced collapse in deep loess threatens the long-term safety of deep-buried metro tunnels. A field sand-well immersion test is conducted along a Xi’an metro line, employing a water-level control system to regulate the leaching exploratory well water level precisely. This experimental setup simulates the wetting-induced deformation process under bottom-up infiltration with constant overburden stress, and a computational model for deep loess collapse deformation is established by considering the hydro-mechanical path. Results demonstrated an inverted-funnel-shaped moisture diffusion pattern in deep loess, with the saturation front diffusion angle measuring approximately 90° within 2 m of the well, decreasing to 50° at distances of 2–6 m, and increasing to 73° beyond 6 m. During immersion, the deep loess exhibits three-stage deformation behavior: collapse governed by structural strength degradation, rebound dominated by unloading due to cavity formation with a positive correlation to water level height, and compression from residual structural strength failure with a negative correlation to water level height. Post-immersion consolidation settlement is also observed. Collapse and rebound develop from deep to shallow layers and from inner to outer zones, whereas consolidation settlement propagates from shallow to deep layers and from outer to inner areas. Based on the wetting-unloading hydro-mechanical path during bottom-up infiltration, a collapse deformation model is developed. Using a degree of wetting η1 = 0.8 combined with actual unloading ratios, the model achieves a relative error of only 8.85 %. This study provides valuable insights for evaluating collapsibility in deep loess foundations within groundwater fluctuation zones.]]></description>
      <pubDate>Tue, 21 Apr 2026 14:30:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2653173</guid>
    </item>
    <item>
      <title>Sensitivity of Predicted Flexible Pavement Performance to Unbound Material Hydraulic Properties</title>
      <link>https://trid.trb.org/View/2191971</link>
      <description><![CDATA[The analysis methodology developed in new AASHTO mechanistic-empirical pavement design guide (MEPDG) includes the influence of diurnal and seasonal temperature and moisture variations on material and pavement behavior. However, the sensitivity of predicted flexible pavement performance to variations in the thermo-hydraulic input properties of the unbound pavement materials is not well established. The sensitivity of predicted pavement distresses to subgrade type, groundwater table depth, saturated hydraulic conductivity, and soil water characteristic curve parameters are quantified for three flexible pavement sections in four climate locations. Overall, the unbound material environmental inputs related to groundwater depth, soil water characteristic curve parameters, and saturated hydraulic conductivity all had slight to negligible influence on the predicted distresses for the cases considered in the study. The influences of climate and subgrade type predicted performance were sensible in their trends.]]></description>
      <pubDate>Mon, 23 Mar 2026 15:24:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2191971</guid>
    </item>
    <item>
      <title>A Case History of Construction Induced Sinkholes</title>
      <link>https://trid.trb.org/View/2191877</link>
      <description><![CDATA[This paper presents the case history of 77 sinkholes recorded during the Suncoast Parkway construction, in west-central Florida. These sinkholes occurred where limestone bedrock was excavated. The excavation revealed numerous preexisting solution pipe features in the limestone that were in-filled with clean fine sand. These features were pre-existing sinkholes and served as conduits to recharge the aquifer. The sinkholes that occurred during construction were re-openings of these pre-existing sinkholes. It is also believed that the bedrock excavation had altered the pathways of groundwater recharge at the overburden soil and bedrock interface. Specifically, the bedrock excavation directed larger volume of surface runoff into some pre-existing sinkholes, which previously did not experience large water recharge in recent geological history. The concentration of runoff destabilized the in-filled fine sand and caused the sinkholes to re-open during construction. Implemented remedial measures included hydraulic backfill, grouting, and installation of geotextile. The goal was to minimize potential sinkhole occurrence on the travel lanes of the new highway. Since the end of construction, maintenance records showed sinkholes had occurred only in retention ponds and swales during rainy seasons. They occurred frequently during the first three years after construction and have not been observed after; indicating that a new equilibrium has been reached and the remedial measures in the roadway area were successful.]]></description>
      <pubDate>Mon, 23 Mar 2026 15:24:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2191877</guid>
    </item>
    <item>
      <title>Using WiscLEACH to Estimate Groundwater Impacts from Fly Ash Stabilized Layers in Roadways</title>
      <link>https://trid.trb.org/View/2191876</link>
      <description><![CDATA[This paper presents a modeling study to evaluate the impacts of leaching on groundwater from fly ash stabilized layers in roadways. The computer program, WiscLEACH, based on two analytical solutions for the advection-dispersion-reaction process in the subsurface was used. The analytical method was compared to predictions made with IWEM roadway module, which was developed for assessing the potential for groundwater impacts caused by leaching from industrial material resources used as pavement materials in roadway construction. Predictions made with WiscLEACH and IWEM were compared to field data from a highway test section where the subgrade was stabilized with coal fly ash. Comparison with the field data showed that 90th percentile exposure level predicted by IWEM and concentrations predicted by WiscLEACH at a monitoring well were higher than measured data, which suggests that the predictions are conservative. Factors related to lower predicted concentrations of IWEM than WiscLEACH were discussed.]]></description>
      <pubDate>Mon, 23 Mar 2026 15:24:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2191876</guid>
    </item>
    <item>
      <title>Injection of a Ventilation Tower of an Underwater Road Tunnel Using Cement and Chemical Grouts</title>
      <link>https://trid.trb.org/View/2200040</link>
      <description><![CDATA[This paper presents the monitoring and the grouting works of an immersed road tunnel. As this underground structure is almost 30 years old, groundwater has gradually damaged and penetrated the concrete, bringing water problems in the winter as the water forms into ice that can fall on cars or damage electrical equipment. To understand the problem related to water infiltration and find solutions, instruments were installed to monitor the movement of a horizontal construction joint and exploratory drilling was conducted in the concrete ventilation tower structure. These investigations led to choosing two solutions: a first phase of cement grouting and a second phase of chemical grouting were carried out between 1998 and 1999. From the different available observation locations, both grouting methods gave satisfactory results for the stopping of water leakages in the ventilation towers.]]></description>
      <pubDate>Fri, 06 Feb 2026 13:53:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/2200040</guid>
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