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    <title>Transport Research International Documentation (TRID)</title>
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    <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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Principles of Ground Water Control through Pregrouting in Rock Tunnels</title>
      <link>https://trid.trb.org/View/2200036</link>
      <description><![CDATA[The principles of pregrouting as presented here are based on nearly 40 years of experience of pre- and post-grouting in rock tunnels in different parts of the world.]]></description>
      <pubDate>Fri, 06 Feb 2026 13:53:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/2200036</guid>
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    <item>
      <title>Report of Geological Investigation of Two Rock Cuts &amp; One Tunnel Site in Carlin Canyon, Elko County, Nevada</title>
      <link>https://trid.trb.org/View/2635924</link>
      <description><![CDATA[The Carlin Canyon area is located at the intersection of the westward-flowing Humboldt River and an unnamed range of hills. These hills trend north-south and are probably a northern extension of the Pinyon Range. In the vicinity of the examined area, Mississippian chert-pebble conglomerates (Tonka formation) are separated by an angular unconformity from the overlying (Strathearn formation) calcarenites of Late Pennsylvanian age. A detailed examination of the tunnel site area was made by the writer. This included the examination of the surface geology and underground geology. The underground geology was examined in the Southern Pacific Railroad tunnel and in the Western Pacific Railroad tunnel which run parallel to the proposed highway tunnel. The excellent geologic data obtained from the surface and underground precludes the necessity for boreholes in this area.]]></description>
      <pubDate>Mon, 12 Jan 2026 11:27:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2635924</guid>
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      <title>Blasting and Sliding Parameter Optimization for Efficient Autonomous Construction Rock Debris Sliding Transportation in an Inclined Shaft</title>
      <link>https://trid.trb.org/View/2592039</link>
      <description><![CDATA[In the construction of inclined shaft projects, the efficient transportation of rock debris following blasting excavation is a crucial factor affecting the progress of the construction schedule. Given that traditional rock debris transport by trucks is both time-consuming and labor-intensive, utilizing height differentials for autonomous rock debris sliding transport offers green, low-carbon, and highly efficient advantages. When the shaft’s inclination is small, the inclination of the sliding surface and the gradation of blast fragments are key factors influencing the stability and efficiency of autonomous rock debris transport. This study aims to determine the optimal blasting parameters and sliding surface characteristics through model experiments to enable autonomous rock debris transport in gently inclined projects. In this paper, we first examined the rock debris sliding process in the construction of gently inclined shafts, developed a model testing device for rock debris sliding, and conducted 75 sets of model tests, with shaft inclination and blast fragment gradation as the primary variables. We analyzed the main factors affecting autonomous rock debris sliding and determined a minimum shaft inclination of 34° and the corresponding optimal blasting gradation. These findings were successfully applied in a real-world project, achieving efficient, autonomous rock debris transport. It provided a sustainable and energy-efficient alternative to traditional construction rock debris transportation methods, offering a design reference for rock debris transport in similar hydropower plants, underground mining, and tunnel excavation projects.]]></description>
      <pubDate>Thu, 13 Nov 2025 16:59:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2592039</guid>
    </item>
    <item>
      <title>Current Practices in Rock Scaling</title>
      <link>https://trid.trb.org/View/2611090</link>
      <description><![CDATA[Rockfalls, which result from the chemical and physical weathering of aging exposed rock cuts, occur frequently along many Kentucky roadways and can endanger travelers. Mitigating rockfalls often requires substantial excavation, procuring additional right of way, and/or hiring specialty contractors. An alternative to these expensive processes is rock scaling, which can be a cost-effective tool for mitigating rockfalls. Rock scaling entails removing loose and unstable rocks from rock cut slopes within the right of way to reduce rockfall risk and is being used with increased frequency by state transportation agencies around the country. The Kentucky Transportation Cabinet (KYTC) has completed several rock scaling projects. However, the agency lacks specifications or administrative guidance that staff can use to develop and execute projects. Based on information found in published literature, specifications issued by other agencies, and input from Cabinet staff, Kentucky Transportation Center (KTC) researchers developed the Rock Slope Scaling Guidance and Procedures Manual and construction specifications for rock scaling projects. The manual contains guidance on project prioritization, funding sources, developing contracts, inspection, post-construction monitoring, and other information staff need to develop and manage rock scaling projects. The specifications address contractor and personnel qualifications, submittals, construction requirements, quantity measurement, and pay items. Both documents give KYTC the flexibility to evaluate multiple methods for qualifying contractors, developing contracts, measuring quantities, and paying contractors on rock scaling projects.]]></description>
      <pubDate>Wed, 22 Oct 2025 09:02:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2611090</guid>
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    <item>
      <title>Numerical and experimental analysis of contact pressure in rock-disc cutter interaction using displacement discontinuity method and digital image correlation</title>
      <link>https://trid.trb.org/View/2557042</link>
      <description><![CDATA[Accurately predicting contact pressure distribution in rock-disc cutter interaction is crucial for optimizing tunnel boring machine (TBM) performance. This study presents a numerical and experimental investigation of contact pressure using the Higher-Order Displacement Discontinuity Method (HODDM) and Digital Image Correlation (DIC). The numerical model was developed to analyze stress and strain distributions under varying cutter force conditions, and its results were validated through controlled experimental testing using a linear cutting simulator. The numerical analysis reveals that pressure distribution follows a downward parabolic trend, with peak values concentrated in the central contact zone. This trend was also confirmed from experimental DIC measurements. The study further investigates the influence of the rotational-to-normal force ratio (Fr/Fn) on stress concentration, showing that increasing this ratio amplifies peak pressure and alters crack propagation patterns. Additionally, the proposed FWxM criterion quantifies pressure distribution zones, demonstrating that higher Fr/Fn ratios lead to a broader pressure spread beneath the cutter, potentially improving rock fragmentation efficiency. These findings enhance the understanding of rock fracturing mechanisms and provide a validated approach for predicting cutter forces, aiding in TBM cutter design optimization. The results indicate that accurate pressure distribution modeling can contribute to reducing cutter wear and enhancing excavation efficiency in hard rock tunneling.]]></description>
      <pubDate>Wed, 16 Jul 2025 09:51:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2557042</guid>
    </item>
    <item>
      <title>Probabilistic rock mass quality prediction model and its application to tunneling design (UTI-UTC 31)
</title>
      <link>https://trid.trb.org/View/2543424</link>
      <description><![CDATA[This project develops a probabilistic framework for predicting rock mass quality and integrating uncertainty into tunneling design. By applying statistical methods to geotechnical investigation data—such as rock quality designation (RQD), uniaxial compressive strength (UCS), and joint spacing—the model estimates spatial variability and classifies ground conditions using the Q-system. Monte Carlo simulations are employed to generate rock mass quality distributions along tunnel alignments, which in turn inform support system selection and tunnel stability assessments. The research also includes sensitivity analyses to determine the influence of each geotechnical parameter on tunnel design decisions. The probabilistic approach enhances current deterministic design practices by quantifying risks, improving adaptability in challenging geological settings, and supporting more robust engineering decisions for underground infrastructure projects.
]]></description>
      <pubDate>Wed, 07 May 2025 17:19:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2543424</guid>
    </item>
    <item>
      <title>Evaluation of rock cutting performance of conical cutting tool based on commonly measured rock properties</title>
      <link>https://trid.trb.org/View/2408442</link>
      <description><![CDATA[Efficiency of rock cutting process plays a critical role in performance of mechanical excavation units. The composition of cutting forces (normal and drag force acting on cutting tools) and the total force (FT), specific energy (SE), and percent of fine material (FM) produced in cutting process are important indicators of efficient cutting process. The other key factors in assessment of machine performance are tool wear, energy consumption, dust production, and machine maintenance, availability, and utilization. In this study, small scale linear cutting experiments were performed with a conical pick on thirteen sedimentary and metamorphic weak to medium strength rock samples at a range of 0.5 to 6 mm cutting depths in unrelieved cutting mode. FT was measured by using a 3D dynamometer and recorded by the data acquisition system, and FM was determined by sieve analysis. Finally, SE was calculated using both the cutting force signal and the volume of the cuttings for each test. Subsequently, an analysis of the effective cutting geometry was performed based on cutting depth, using the specific energy as an indicator of cutting efficiency. Statistical and regression analysis was used to correlate FT, SE, and FM with the rock properties and cutting geometry. The results revealed that the uniaxial compressive strength, Schmidt rebound number, and density are the main parameters that affect FT and SE, and the brittleness index is the main parameter that affects FM. A nonlinear predictive model is introduced that offers a reasonable estimate of FT, SE, and FM to assist engineers in determining the effective operational cutting geometry for a given rock type for unrelieved cuts.]]></description>
      <pubDate>Wed, 28 Aug 2024 09:04:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2408442</guid>
    </item>
    <item>
      <title>Stability and Reinforcement Analysis of a High and Steep Cataclastic Rock Slope</title>
      <link>https://trid.trb.org/View/2203566</link>
      <description><![CDATA[This analysis is based on a highway project in Guangdong province, involving a tall, steep, and rock-excavating slope with cataclastic structures. Quantitative analysis of the stress-strain trend, possible failure models and safety factors during the slope excavation were investigated by the discrete element program UDEC. The following results were obtained: (1) The slope with joint fissure developed was in anticlinal core and the stability was greatly influenced by the extroversion of rock level. (2) The primitive balance of the slope was broken during the excavation, which induced large range shear failure zone in the internal part of the slope, and the whole circle-broken similar to soil slope appeared. (3) The excavation slope was in a critically stable state, but wide area landslide could be induced by certain triggering factors. Based on these results, a comprehensive treatment scheme was adopted and implemented through the methods, such as reinforcing the broken rock with concrete lattice beam-anchor (cable); minimizing erosion and preserving the slope strength with an efficient drainage system; and protecting the slope with grouted rubble. The integrity of the high standard highway was maintained and the slope was reinforced during time the plan was carried out.]]></description>
      <pubDate>Thu, 25 Jul 2024 17:12:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2203566</guid>
    </item>
    <item>
      <title>Research on Rock Support Technology of Railway Tunnels Based on Geomechanical Model Tests</title>
      <link>https://trid.trb.org/View/2381760</link>
      <description><![CDATA[The technology of combining a negative Poisson's ratio (NPR) anchor cable with a double-layer truss support technology (N-DTST) is a new support technology for deeply buried tunnels. To evaluate the stability of the surrounding rock support after the application of this new support technology in the Sichuan–Tibet Railway tunnels, geomechanical model tests were conducted for the first time. A model test loading system with intelligent numerical control and automated analysis was developed to reveal the changing patterns of displacement and stress in the surrounding rock of tunnels. The test results revealed the following: (1) After the burial depth exceeds 800 m, the tunnel undergoes large deformations with displacements greater than 37.5 mm, and the traditional anchor cable support fails; (2) In the burial depth range of 800–2,000 m, the new support technology can control the surrounding rock deformation, and the surrounding rock displacement is less than 10 mm; (3) After the tunnel excavation, the radial stress decreases and the tangential stress concentrates. When the burial depth is greater than 800 m, the radial stress compensation provided by the anchor cable no longer meets the stability of the tunnel surrounding rock, and the new support technology can provide high stress to support the deeply buried tunnel; (4) After the burial depth exceeds 2,000 m, butterfly-shaped damage occurs on the tunnel surface, the truss structure inside the tunnel is damaged, and the support structure fails, so it is recommended to carry out reinforcement support at the arch shoulder. The research results verify the effectiveness of the new support technology and provide an important reference for the support of the surrounding rock in deeply buried tunnels.]]></description>
      <pubDate>Fri, 14 Jun 2024 10:27:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2381760</guid>
    </item>
    <item>
      <title>Study on Safety Analysis of the Adjacent Operation Tunnel Under the Blasting Load</title>
      <link>https://trid.trb.org/View/1974186</link>
      <description><![CDATA[In order to study the dynamic response of the operation tunnel lining and the accuracy of taking strains as the controlling parameter when the adjacent rock was blasted, field experiments were carried out based on the blasting excavation of a new closely spaced tunnel engineering in Zhangjiajie. Meanwhile, particle vibration velocity in the surrounding rock at different distances from the explosion source was simulated through the dynamic finite element method. On the basis of vibration velocity field measured and numerical calculated, the propagation process of shock wave and strains and stress state of existing operation tunnel lining were analyzed at the key position. The comparison with field monitoring data indicates that the maximum vibration speed occurs at the radial direction of tunnel wall facing the blasting side, making defects of the tunnel lining easy to deteriorate. The vibration velocity decreases nonlinear along with increase of distance away from explosion source. Impact on tunnel wall facing the blasting side and arch lining is more serious when the adjacent rock was blasted. Through the study, the vibration velocity and strains as double controlling factors are credible in the actual near distance blasting engineering. The work of the study can provide a significant reference to similar projects.]]></description>
      <pubDate>Wed, 08 Nov 2023 15:51:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1974186</guid>
    </item>
    <item>
      <title>A Comprehensive Approach to Rock Slope Design Solutions along NC-88 in Ashe County, North Carolina</title>
      <link>https://trid.trb.org/View/2236958</link>
      <description><![CDATA[In early 2023, HDR performed detailed surveys of multiple rock slopes along 3 miles of NC-88 in support of realignment efforts of a critical highway corridor between Warrensville and Smethport in Ashe County, North Carolina. The project alignment is physiographically situated in North Carolina’s Eastern Blue Ridge Province. The local lithology generally consists of amphibolite, biotite gneiss, and mica schist of the Ashe Metamorphic Suite / Tallulah Falls Formation (Neoproterozoic). The proposed project involves multiple rock cuts to support widening and realigning NC-88, with some cuts exceeding 200 feet in height. Design complexities include difficult terrain, limited sight distances, increased traffic, rockfall hazards, and limited right-of-way access. HDR executed a comprehensive approach to rock slope design, which included inspecting and geohazard scoring of existing rock cuts using the Unstable Slope Management Program (USMP) method and detailed geologic mapping of over 1,100 discontinuities on existing rock cuts. At a critical section of the project, seismic refraction and MASW surveys were performed, and an angled bore was advanced to 132.5 feet in depth to collect rock core and inspect subsurface discontinuities with optical/acoustic televiewing. Collected data was used to inform global and subglobal (rockfall) stability analyses for each proposed cut, which revealed a high likelihood of planar and wedge failures at some of the most significant cuts. Preliminary design solutions, estimated quantities, long-term maintenance considerations, and right-of-way impacts customized for each proposed cut were then presented to NCDOT.]]></description>
      <pubDate>Fri, 01 Sep 2023 09:47:57 GMT</pubDate>
      <guid>https://trid.trb.org/View/2236958</guid>
    </item>
    <item>
      <title>Experimental and Analytical Study on Optimal Spacing for Hard-Rock Breaking under Double-Indenter Impact</title>
      <link>https://trid.trb.org/View/2221816</link>
      <description><![CDATA[Rock breaking by double hydraulic hammers has a wide application prospect in hard-rock roadway excavation because of its environmental protection and strong rock-breaking ability, but the optimal spacing under double-indenter synchronous impact is not clear. Based on the rock-breaking experimental system under double-indenter synchronous impact established by combining a detachable double-indenter device and Hopkinson pressure bar, the impact tests of three kinds of rocks are carried out, and a theoretical model of specific energy consumption is derived to determine the optimal spacing. The results show that when the indenter spacing is 28 mm, 42 mm, and 14 mm, respectively—that is, when the cross section of the fragmentation crater is in the shape of a “peanut” with a fine middle and two large ends—the concrete, limestone, and sandstone specimens reach the minimum specific energy consumption, which is reduced by 22.55 %, 30.60 %, and 11.85 %, respectively, compared with single-indenter impact. The theoretical model, which explains and verifies the experimental phenomena and results well, can be divided into four zones, and the optimal spacing is in Zone III. The research can be helpful for actual hard-rock tunneling under double hydraulic hammers.]]></description>
      <pubDate>Thu, 31 Aug 2023 10:11:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2221816</guid>
    </item>
    <item>
      <title>Characterization of a fractured rock mass using geological strength index: A discrete fracture network approach</title>
      <link>https://trid.trb.org/View/2146499</link>
      <description><![CDATA[Rock mass poses wide heterogeneity due to the presence of structural discontinuities. The failure in the rock mass may cause a serious concern to road and rail transportation. Rock mass characterization is a first step towards preliminary investigation for road or tunnel excavations. Different field-based methods were developed to characterize the rock mass conditions. The Geological Strength Index (GSI) is a simple and commonly adopted method with broad applicability in rock engineering. Traditional approaches are limited to 2D exposers for mapping purposes, but block formation or joint intersection is a 3D parameter. The advancement in computational techniques led to significant involvement of numerical modeling techniques such as discrete fracture network (DFN). The remote sensing techniques render the data with high precession potential not accessible with conventional methods. The stochastic DFNs generated based upon the statistical distribution of the input parameters can represent the natural fracture system in 3D. The developed synthetic fracture network can be used to examine the rock mass characteristics. This work addresses the incorporation of the Discrete Fracture Network (DFN) in the estimation of the Geological Strength Index (GSI) of the rock mass. The work compares the results of DFN generated using aggregate and disaggregate approaches in block size distribution (BSD) and rock quality designation (RQD) measurement for a fractured slope. The calculated BSD and RQD using DFN and field-estimated joint conditions parameters are used to estimate GSI of the rock mass. A machine learning based python GUI tool was developed to find GSI from block volume and joint condition parameters. The prediction of GSI from input parameters using machine learning has led to systematically digitizing the standard GSI chart.]]></description>
      <pubDate>Tue, 23 May 2023 10:08:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2146499</guid>
    </item>
    <item>
      <title>Study on Treatment Measures for Large Deformation of the Primary Support of the Kalumoqi Tunnel</title>
      <link>https://trid.trb.org/View/2056004</link>
      <description><![CDATA[The deformation of a primary support is one of the difficult problems often encountered in the excavation of a deep-lying soft rock tunnel. Directed against the problems of the large deformation of the primary support, the cracking of the lining, and the sinking of the vault in the Kalumoqi Tunnel that is being built, the classification of surrounding rock and deformation monitoring are carried out, and the causes of the disease are analyzed. On this basis, the measures for changing the supporting parameters are proposed. Finite-element software is used to verify the supporting effect of the changed parameters by numerical simulation, and the construction effect is evaluated by on-site monitoring. The results show that: (1) part of the vault is peeling and the cracking phenomenon of the sprayed concrete when disease occurs, the deformation of parts has obviously sustained growth, the deformation velocity value is larger, longitudinal connecting steel bar and steel arch shelf of primary support show strong tensile deformation, steel arch shelf of primary support at the arch foot has broken, and the deformation of the primary support of the tunnel is larger, showing an extruded deformation as a whole. The convergence value and rate at the arch foot are greater than those at the arch top, and the maximum convergence value of the arch foot is 50 mm, and the maximum convergence rate is 29 mm/d. The convergence of the arch foot has a sudden change, and the deformation shows a trend of continuous increase. (2) The numerical simulation results show that the displacement of the subsidence of the sinking vault, the arch waist, and the arch foot decreases by 80%, 90.8%, and 96.2%, respectively, compared with the original support parameters. The changed SVa support parameters produce less displacement deformation, and the deformation at the vault, the arch waist, and the arch foot all meet the requirements of the design code, which can ensure the safety of the tunnel construction and the stability of the structure. (3) By comparing the numerical simulation with the field measured data after the parameter changes, it is found that the sinking vault, the convergence of the arch waist, and the displacement of the arch foot is significantly reduced, the problem of the large deformation of the primary support is solved, the overall deformation of the surrounding rock tends to be stable, and the shape of all the supporting forms of the tunnel is intact without obvious damage phenomenon.]]></description>
      <pubDate>Wed, 30 Nov 2022 10:57:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/2056004</guid>
    </item>
    <item>
      <title>Influence of Wavelength-to-Excavation Span Ratio on Dynamic Failure Characteristics of a Deep-Buried Tunnel Subjected to Disturbance</title>
      <link>https://trid.trb.org/View/1997868</link>
      <description><![CDATA[Deep-buried structures are frequently and inevitably subjected to aperiodic perturbation during their life circle, resulting in damage to the rock mass surrounding the structures under the coupled action of excavation-induced local stress and dynamic perturbation. The investigation presented in this paper concentrates on the analytical and numerical dynamic responses around an unsupported deep-buried tunnel subjected to blasting disturbance with different wavelength-to-excavation span ratios (λ/D). Based on the complex function theory, the integral transform and its inversion, the elastic responses around the tunnel are obtained theoretically. Then the corresponding elastoplastic counterparts are explored using a self-developed code: elastoplastic cellular automaton. The analytical results indicate that Poisson’s ratio, the ratio of total time for blasting load to rising time, and λ/D have a significant influence on the distributions of dynamic stress concentration and velocity vibrations. Moreover, the numerical results reveal that tensile failure and the compression–shear counterpart are major damage mechanisms for the rock mass when the wavelength is less than the excavation span, while the compression–shear failure is major damage mechanism when the wavelength exceeds the excavation span. The analytical and numerical results can provide guidance for the support of deep-buried rock tunnels.]]></description>
      <pubDate>Fri, 29 Jul 2022 09:21:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/1997868</guid>
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