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    <title>Transport Research International Documentation (TRID)</title>
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    <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>
    </image>
    <item>
      <title>Precision Tunnelling Under Heritage Building in Sydney CBD</title>
      <link>https://trid.trb.org/View/2406899</link>
      <description><![CDATA[The design of a pedestrian tunnel has been completed as a part of the integrated station design of Metro Martin Place (MMP). This tunnel connects two deep station entrance shafts (up to 28 m deep) and is located immediately below a hundred-year-old heritage building in Sydney CBD area. The heritage building is ornately finished and therefore extremely sensitive to ground movement. During detailed design, it was identified that Mass Concrete Backfill (MCB) supporting the building foundations was found to extend within the tunnel profile. Numerical modelling was carried out to assess the design of tunnel support for ground and building loads. It has also been used to estimate the surrounding ground deformation and foundation settlement of the building. The tunnel is mainly formed within Hawkesbury Sandstone impacted by the Martin Place Joint Swarm. The ground model including overall stratigraphy, in-situ stress condition, and rock/joint parameters was developed according to available borehole information, surrounding tunnel and excavation mapping, and past project experience. 3DEC software package was utilised to develop a local model and a global model simulating the interaction between rock and joints due to the tunnelling using determinate Discrete Fracture Network (DFN). The local model assessed sensitivity of MCB in terms of settlement due to different rock-MCB interface parameters. The global model captured the overall ground deformation and considered the effects of staged construction for the entire project site. The numerical results formed the basis of final tunnel support design, the impact assessment of the heritage building and monitoring strategies to minimise the impact on the building above and provide safe design.]]></description>
      <pubDate>Wed, 19 Mar 2025 10:12:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/2406899</guid>
    </item>
    <item>
      <title>Stability assessment of jointed rock capturing roughness degradation under cyclic loading with special reference to railway formation</title>
      <link>https://trid.trb.org/View/2400562</link>
      <description><![CDATA[Repeated train loading on a jointed rock subgrade can cause excessive displacements of certain discontinuities leading to instability. Repeated shearing of discontinuities leads to a gradual reduction in joint roughness (i.e. wearing of asperities), which is quantified by the change in the joint roughness coefficient (JRC). This process reduces the joint shear strength over time. In this study, the classical shear strength criterion proposed by Barton and Choubey (1977) is extended to capture the influence of cyclic loading on joint degradation and the corresponding shear strength reduction, also considering the scale effect. This modified cyclic shear strength is implemented in FLAC-3D and validated with conventional cyclic triaxial data available from selected past studies. The model is applied to a simulated real-life track operating over a jointed sandstone formation commonly found towards the eastern coast of NSW. A modified limit equilibrium approach based on an Equivalent Factor of Safety (EFOS) is introduced and adopted to quantify the extent of instability, whereby an increase in the number of loading cycles affects a decrease in the EFOS of an unstable block. For a specific joint strike inclined to the track, the potential adversities are exacerbated when the joint dip angle is greater and when the initial JRC is smaller. In this paper, alternative geometrical combinations and different initial joint properties are considered to determine the worst combination of JRC and joint orientation upon cyclic train loading. As most past studies adhere to traditional static load analyses, the extended shear strength criterion described in this study is novel, and it offers significant practical benefit for railways that are subjected to prolonged cyclic loading.]]></description>
      <pubDate>Fri, 26 Jul 2024 10:00:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2400562</guid>
    </item>
    <item>
      <title>Research on Intelligent Detection and Segmentation of Rock Joints Based on Deep Learning</title>
      <link>https://trid.trb.org/View/2387528</link>
      <description><![CDATA[The current methods for detecting joints on tunnel face rely primarily on manual sketches, which are associated with issues of low detection efficiency and subjectivity. To address these concerns, this paper presents an intelligent recognition and segmentation algorithm based on Mask R-CNN (mask region-based convolutional neural network) for detecting joint targets on tunnel face images and automatically segmenting them, thereby improving detection efficiency and objectivity of the results. Additionally, to tackle the challenge of low detection accuracy in existing image processing methods, particularly for complex tunnel joint surfaces in dark environments, the paper introduces a path aggregation network (PANet) to enhance the fusion capability of feature information in Mask R-CNN, thereby improving the accuracy of the intelligent detection method. The algorithm was trained on a dataset of 800 tunnel face images, and the research findings demonstrate that it can quickly detect the position of joints on tunnel face images and assign masks to the joint pixel regions to achieve joint segmentation. The mean average precision (mAP) of the detection boxes and segmentation in the 80 test set images were 58.0% and 49.2%, respectively, which outperforms the original Mask R-CNN algorithm and other intelligent recognition and segmentation algorithms.]]></description>
      <pubDate>Mon, 10 Jun 2024 08:44:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2387528</guid>
    </item>
    <item>
      <title>Experiment and particle flow simulation of unloading induced shearing properties for jointed sandstone materials</title>
      <link>https://trid.trb.org/View/2300591</link>
      <description><![CDATA[Shear tests on sandstone containing non-connected joints under the unloading normal stress but fixed shear stress conditions were conducted with various initial normal stress and unloading rate. During the unloading process, continuous shear dilation could be observed. For initial normal stress = 5–20 MPa, the sliding initiation normal displacement decreased by 17.14–66.32 % but the sliding initiation shear displacement increased by 21.91–98.19 %. The sliding initiation normal stress declined by 7.18–15.57 % for unloading rate = 0.002–0.01 MPa/s but increased by a factor of 3.18–3.53 with the initial normal stress. Shear sliding of the jointed samples was more prone to occur at a smaller initial normal stress with a larger unloading rate. From the numerical simulation results via PFC2D, during the unloading process, cracking was first initiated from central part of the rock bridge and propagated gradually to coalesce with cracks developed from the joint tips. The penetrating fracture surfaces led to shear sliding of the jointed samples, and shear wear occurred on the fractures as shear displacement continued increasing. For unloading rate = 0.002–20 MPa/s, quantity of cracks corresponding to shear displacement of 1.2 mm decreased by 12.18–36.34 %. Cracking degree was more serious for the samples at a low unloading rate due to progressively developed cracks near the main failure planes before shear sliding and more accumulated cracks in the shearing wear stage for fractures under a larger normal stress.]]></description>
      <pubDate>Fri, 19 Jan 2024 16:42:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2300591</guid>
    </item>
    <item>
      <title>Stability analysis of jointed rock mass in large underground caverns based on multi-scale analysis method</title>
      <link>https://trid.trb.org/View/2249002</link>
      <description><![CDATA[Random defects at different scales are the crucial cause of damage evolution and cascade transfer in rocks. For a large-scale underground cavern, the rock mesoscopic heterogeneity and macroscopic random joints are inevitable factors of rock stability, which needs to be further studied. In this study, a multi-scale analysis method for the stability of jointed rock mass in large underground caverns is proposed. The statistical damage theory is used to describe the mesoscopic heterogeneous rock damage. Monte Carlo simulation and measured joint geometric information are combined to reconstruct the macroscopic random joint network of rock mass. The integrated analysis of mesoscopic heterogeneity of rock and the macroscopic response of random jointed rock mass is performed by Rock Failure Process Analysis (RFPA) system. The research shows that the existence of joint affects the failure mode of rock mass and strengthens the heterogeneity. The representative elementary volume (REV) of jointed rock mass and its equivalent mechanical parameters are determined and used in the stability analysis of a large-scale underground cavern project. Results show a good agreement with the in-situ monitoring deformation of surrounding rock mass, which verifies the effectiveness of the rock mass multi-scale analysis method.]]></description>
      <pubDate>Mon, 16 Oct 2023 17:25:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2249002</guid>
    </item>
    <item>
      <title>BeFo 440 - Injektering av bergsprickor under höga hydrauliska gradienter</title>
      <link>https://trid.trb.org/View/2269727</link>
      <description><![CDATA[Grouting of rock joints with considerable hydraulic gradient, i.e. flowing water, is a challenging issue in many rock engineering projects. Typical situations include post-excavation grouting and remedial grouting of dam foundations. There is still a need for basic research regarding the behaviour of the fresh grout in flowing water. Not until we understand this complex hydromechanics will it be possible to develop reliable design methodologies that can predict the decrease in hydraulic conductivity of the grouted rock mass. We propose an experimental research project to investigate 1) the erosion of fresh grout during grouting in flowing water, and 2) the likely favourable effect of relief wells that reduces the hydraulic gradient. In addition, we plan to develop a design methodology for remedial grouting of dam foundations, and a case study related to the subject will be made. The findings will be relevant also for post-excavation grouting in tunnels with similar hydraulic environments. The project results can therefore be highly useful in future application studies for post-excavation grouting. The project is part of a PhD project at KTH.]]></description>
      <pubDate>Mon, 16 Oct 2023 09:26:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2269727</guid>
    </item>
    <item>
      <title>Jointed rock masses as metamaterials – Implications for railway tunnel vibrations</title>
      <link>https://trid.trb.org/View/2189390</link>
      <description><![CDATA[Vibrations from underground railways are known to affect receptors located close to the tunnel. Understanding the transmission pathway between these tunnels and receptors is important in determining the magnitude of vibrations which can be transmitted. Rail tunnels can be excavated in a range of geological conditions, including jointed rock masses. Jointed rock masses have been found to display certain resonant characteristics, namely spring resonance. Therefore, this paper studies the resonant characteristics of jointed rock masses using a series of models solved using the combined discrete element-finite difference method and the finite difference method. Modelling assumptions are tested as well as different equivalent material models. It is found that spring resonances occur at the same frequencies as predicted by analytical functions when different modelling assumptions are used. This indicates that the spring resonance effect will prevail in complex rock masses under a range of geological settings. The spring resonance mechanism is found to cause jointed rock masses to behave like periodic metamaterials in respect to the transmission of stress waves, which can operate as a band-pass or low pass filter, depending on the number of joints within the material. New evidence is presented showing that periodic metamaterials exhibit spring resonance. Results for metamaterials in laboratory scale frequency sweep tests are shown to feature high transmission zones occurring at the predicted spring resonant frequency for that material. Finally, the effects of the spring resonance mechanism operating within the jointed rock masses are appraised in the context of vibrations from railway tunnels.]]></description>
      <pubDate>Wed, 19 Jul 2023 09:38:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2189390</guid>
    </item>
    <item>
      <title>Mechanical Behavior of Grouted Rock Joints</title>
      <link>https://trid.trb.org/View/1985120</link>
      <description><![CDATA[Grouting is one of the most widely used reinforcement methods in geotechnical engineering. In this work, the mechanical behavior and in particular the shear properties of rock joints due to grouting were investigated using direct mechanical tests. It was demonstrated that the initial vertical stresses were related to the initial status of rock joints but hardly influenced by grouting. The normal stiffness was increased with grouting, the peak shear stress was evident after grouting, and the residual shear strength was higher than that without grouting. These results indicate that the grouting strongly affected the shear properties of rock joints. Based on the analysis of these effects, further mechanisms were revealed, and finally, a strength model that considered various grouting parameters for the mechanical behavior of the grouted rock joints was further proposed and discussed.]]></description>
      <pubDate>Mon, 29 Aug 2022 09:27:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/1985120</guid>
    </item>
    <item>
      <title>Stability Analysis of Jointed Rock Cutting Slope Based on Discrete Element Method</title>
      <link>https://trid.trb.org/View/2003214</link>
      <description><![CDATA[The joints in the rock mass are essential for the stability of rocky slopes, and the destabilization damage of the slope is often directly related to the joints. In this study, in order to reveal the instability process and mechanism of rock slopes from a microscale perspective, the DEM simulations for rocky slopes of the K88 + 400∼K88 + 540 section of Zhongkai Expressway are carried out considering the influence of joints. Based on the findings of the on-site jointed structural surfaces, a rocky slope model containing two sets of intermittent joints was constructed, and the linear parallel bond model and the smooth joint model are used to characterize the rock body and joints, respectively. The evolution of microfracture, contact force chain, and particle displacement are analyzed to explore the micromechanism of slope instability. Finally, the triple reinforcement scheme of anchor cable frame and grass planting is proposed. The research results can provide a reference for stability analysis and reinforcement of similar rocky slope projects.]]></description>
      <pubDate>Mon, 22 Aug 2022 16:14:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2003214</guid>
    </item>
    <item>
      <title>Critical shear strain and sliding potential of rock joint under cyclic loading</title>
      <link>https://trid.trb.org/View/1898531</link>
      <description><![CDATA[A new concept of critical shear strain (ετcritical) of rock joint under cyclic loading is presented, and the role of ετcritical in evaluating the sliding potential of rock joint is highlighted. A series of cyclic triaxial tests was conducted on a cylindrical rock joint specimen with a replicated rough surface representing a joint roughness coefficient (JRC) value of 12.6 oriented at 60° with respect to the horizontal plane. The experimental results indicate that the onset of instability of rock joint is suppressed with increase in confining pressure and number of loading cycles (N) until the normalized shear deformation increases beyond a threshold value of ετcritical. Generally, the critical strain of most rock types is considered in the proximity of 1% under small strain conditions, however, in this study, the critical strain concept is extended to the domain of rock joints, and a semi-empirical model to more rigorously quantify the critical shear strain (ετcritical) of rock joint is suggested considering the effect of joint roughness coefficient (JRC), cyclic loading amplitude, and the number of loading cycles (N). Also, a rational classification of Joint Sliding Potential (JSP) based on the ετcritical and normalized total shear strain (εθN) of rock joint is proposed to characterize the cyclic loading induced sliding instability of a rock discontinuity.]]></description>
      <pubDate>Thu, 20 Jan 2022 12:14:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1898531</guid>
    </item>
    <item>
      <title>Experimental and analytical investigation of the shear resistance of a rock joint held by a fully-grouted bolt and subject to large deformations</title>
      <link>https://trid.trb.org/View/1883890</link>
      <description><![CDATA[Failures of rock bolts installed in jointed rock masses due to shear movement along weak joints in bedding rock slopes or underground caverns are common. Existing models to design rock bolts often only consider a rock bolt’s shear behavior in the elastic stage and ignore their larger non-elastic deformations, which significantly underestimates the bolt’s contribution to the joint shear resistance. Therefore, developing an analytical model capable of reflecting the plastic strain‑hardening of rockbolts subjected to large deformation is very necessary for more effective numerical simulation models as well as rock support design. An experimental investigation was conducted on grouted bolts subjected to joint shear movement. The bolt installation angle with respect to the joint was varied in the tests. Pairs of strain gauges attached to the surface of the bolt shank near the joint measured the bolt deformation during the shear testing. The deformation characteristics of the bolt and grout in the elastic and the plastic stages were evaluated. Based on the experimental measurements, a new analytical model to predict the bolt’s ultimate contribution to the shear resistance of a joint was developed. This model considers large deformations. The analytical model includes the influences of the bolt angle, rock mass strength, joint dilation angle, and bolt tensile strain. A comparison of the model predictions with results from large-scale tests and other existing methods shows good agreement with the tests and an improvement over existing methods.]]></description>
      <pubDate>Sun, 31 Oct 2021 19:08:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/1883890</guid>
    </item>
    <item>
      <title>Semi-empirical analytical modelling of equivalent dynamic shear strength (EDSS) of rock joint</title>
      <link>https://trid.trb.org/View/1849483</link>
      <description><![CDATA[A systematic dynamic triaxial series of tests on replicated rough rock joints were carried out, and results clearly highlight the strength attenuation as a function of joint degradation with respect to the number of loading cycles. A novel semi-empirical mathematical model to evaluate the equivalent dynamic shear strength (EDSS) of rock joint is proposed and validated with experimental results based on two sets of rock joints using rough (JRC = 12.6) and relatively smoother (JRC = 7.2) joint specimens.]]></description>
      <pubDate>Thu, 24 Jun 2021 16:43:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/1849483</guid>
    </item>
    <item>
      <title>Shear Characteristics and Strength Criterion of Frozen Joints under Different Opening Degrees</title>
      <link>https://trid.trb.org/View/1770193</link>
      <description><![CDATA[Samples of rock coupling joints were collected from the Jiangluling Tunnel of the G214 line in Qinghai province. Models with surface topographies similar to these joints were manually created. Freezing shear tests under different normal stress conditions were conducted to study the shear mechanical properties of these models. On this basis, the integral form of the peak shear strength criterion of frozen joints was proposed. Results show that the shear process of the ice layer can be divided into four stages, namely, initial deformation, continuously increasing shear stress, ice shearing, and residual shear. During the continuously increasing shear stress stage, the stress-strain curve is concave, and elastic deformation is not evident. Furthermore, the increase rate of shear stress generally rises as normal stress intensifies. In the ice shearing stage, shear stress does not decrease instantaneously, but plastic deformation is now detectable. When the opening degree is greater than the undulation difference of the joint surface under the action of all levels of normal stress, the shear stress in the ice sharply increases and drops due to local failure and reicing. Then, evident difference between the shear processes under freezing and normal temperature conditions was then obtained. On this basis, the failure forms of joint surfaces, theory of ice adhesion strength under different opening degrees and morphologies, and the shear failure forms of frozen joints under different conditions were considered. The integral form of the peak shear strength criterion of frozen joints was proposed. These results can lay a theoretical foundation for the stability analysis of rock mass engineering in permafrost areas.]]></description>
      <pubDate>Mon, 31 May 2021 20:16:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/1770193</guid>
    </item>
    <item>
      <title>RES2020-14: Design Considerations and Limitations of Rock Dowels/Anchors 
Loaded in Shear</title>
      <link>https://trid.trb.org/View/1851967</link>
      <description><![CDATA[In Tennessee, cut rock slopes with exposed discontinuities are often reinforced with grouted steel anchors
installed across the discontinuity to stabilize the system by immobilizing the rock material above the sliding
surface. These elements resist shear loading rather than function in tension. Yet, the steel bar may bend in cases
where the discontinuity is sufficiently large. The purpose of this study was to investigate the performance of
simulated un-tensioned dowel-jointed rock block systems subjected to shear loading and evaluate whether bending
likely occurred as well as its contribution to the reduction in dowel capacity. Variables studied were aperture size
(joint spacing), dowel diameter, and dowel angle of inclination with respect to the joint normal. Physical
experiments were conducted using large concrete blocks to simulate the jointed rock material, steel rebars to
simulate the dowels, and tested in a large-scale direct shear apparatus. A numerical model was developed to extend
the dowel size and joint thickness. A dowel shear capacity design chart was also developed. The chart identifies
the threshold between the pure shear capacity and the reduced capacity due to bending effects as a function of joint
thickness and bar size. Conclusions from this study include (1) rebar double bending phenomenon was inferred
from strain gage data in the case of a large aperture size, (2) bending starts at an aperture size relative to bar
diameter and strength, and reduces the dowel shear capacity by a quantity related to bar size and aperture size, (3)
all results from physical and numerical analyses show sufficient agreement with the governing equations for
theoretical dowel shear and bending conditions to warrant the conservative use of the developed design chart (4)
dowel inclination angle had little influence on ultimate shear resistance, and (5) free and fixed dowel placement
show no significant difference in resistance.]]></description>
      <pubDate>Tue, 11 May 2021 18:22:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/1851967</guid>
    </item>
    <item>
      <title>Geomechanical Model Experiment Study on Deformation and Failure Mechanism of the Mountain Tunnel in Layered Jointed Rock Mass</title>
      <link>https://trid.trb.org/View/1777163</link>
      <description><![CDATA[The Minxian tunnel is a key engineering of the Weiyuan-Wudu expressway that is excavated in layered jointed carbonaceous slate rock mass. During the construction process, the surrounding rocks of the tunnel encountered serious large deformations and failure, which brought about great difficulties to the safety and cost of the tunnel. In order to study the deformation and failure mechanism of the surrounding rocks, a physical model test was conducted, and integrated methods including strain gauges, a digital camera, and noncontact full-field digital imaging correlation technique were used to record the response information of the surrounding rocks. The evolution process of surrounding rocks failure was simulated successfully in the model test, and the deformation characteristics were basically consistent with the actual engineering. The modelling results show that concentrated stresses in the surrounding rocks were very uneven due to developed stratified and jointed rock mass structure. The maximum and minimum concentrated stresses appeared at the vault of the tunnel and left of inverted arc area, and concentration factors were 3.11 and 1.98, respectively. The main forms of surrounding rocks deformation and failure were large area spalling of surface, severe circumferential fractures, serious bending deformations of thin rock layers, and collapse of overlying strata. The maximum displacements occurred at left sidewall and right shoulder of the tunnel and the corresponding actual displacements were 460 mm to 500 mm. Caving and failure took place firstly at several key positions with maximum concentrated stresses or displacements and subsequently gave rise to massive collapse of surrounding rocks.]]></description>
      <pubDate>Fri, 12 Mar 2021 10:05:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1777163</guid>
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