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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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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <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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    <item>
      <title>Mechanism of the inclined and advanced rockbolt support system and dynamic evaluation of its reinforcement range in mechanized tunneling for high-speed railways</title>
      <link>https://trid.trb.org/View/2605358</link>
      <description><![CDATA[To tackle the challenges of tunnel over-excavation, the Chongqing-Kunming High-speed Railway has optimized rockbolt arrangements by replacing traditional radial rockbolts near the tunnel face with pre-stressed inclined rockbolts that are positioned more forward and set at angles of 45° to 60°. This adjustment thereby aims to enhance the stability of the tunnel face, delay steel arch installation, and expand operational space for drilling equipment. Focusing on the case of the Jinyunshan Tunnel, this study employs finite difference modeling (FDM) to analyze the distribution of support stress fields under varying conditions, thereby enabling a quantitative assessment of the rockbolt-reinforced zones. This quantitative evaluation allows for an effective assessment of the feasibility and safety of implementing delayed support sections. Furthermore, triaxial compression simulations that incorporate prestressed rockbolts reveal the impact of confining pressures on the properties of anchored rock masses. Additionally, field and laboratory tests were conducted to further evaluate the effectiveness of tunnel deformation control, the enhancement of surrounding rock stress, and the practical support capabilities of inclined rockbolts. The research results indicate that: (1) The support system establishes an elevated minimum principal stress zone near the tunnel face, enhancing physico-mechanical parameters of the anchored rock as the minimum principal stress increases. (2) With diminishing tunnel face spatial effects, prestress diffusion extends from the vault to the surrounding rock. (3) In the early stages of excavation (0 ∼ 4 m from the tunnel face), inclined rockbolts outperform radial rockbolts by providing more timely support to improve the stress state of the delayed support zone. (4) Critical factors such as burial depth, lateral pressure coefficients, prestress, and rockbolt angle significantly influence the stress field. When the stress in the rockbolts does not exceed their yield strength, optimal support efficiency and cost-effectiveness can be achieved by using 5-meter-long rockbolts installed at a 60° angle.]]></description>
      <pubDate>Thu, 20 Nov 2025 09:10:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2605358</guid>
    </item>
    <item>
      <title>Experimental study on the pullout behaviour of rockbolts with steel fiber-reinforced grout under constant confining pressures</title>
      <link>https://trid.trb.org/View/2212614</link>
      <description><![CDATA[Deep underground excavation in civil and mining engineering motivates the development of high-strength rockbolting reinforcement. A feasible way to promote the performance of the fully grouted rockbolt is using additives to ameliorate grout properties and thus the bolt-grout interfacial behaviour. Here, the authors investigated the mechanical behaviour of fully grouted rockbolt specimens in the steel fiber-reinforced grout (FRG) under various constant confining pressures to pullout loading by the self-developed laboratory-scale rockbolt pullout system. The authors found that the bond strength of the FRG rockbolt specimen can be more than three times high of the plain grout one. The higher the fiber proportion, the greater the bond strength of the FRG rockbolt. When a constant confining pressure was applied, the bond strengths of all the grouted rockbolt specimens were considerably elevated and the bolt rod failure was observed for the FRG rockbolt specimen under 1.0 MPa confining pressure. Compared with the plain grout one, the post-peak failure of the FRG rockbolt specimen of a much higher bond strength was less brittle. The wavy steel fiber performed better in bond strength enhancement and grout cracking mitigation than the straight one mainly due to the crack bridging effect facilitated by its rough geometry. The authors' experimental studies suggested that FRG rockbolting is promising in reinforcing roadways/tunnels in the deep underground environment.]]></description>
      <pubDate>Mon, 28 Aug 2023 09:34:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2212614</guid>
    </item>
    <item>
      <title>Forecasting and Mitigating Rockfall based on Lidar Monitoring: A Case Study from Colorado</title>
      <link>https://trid.trb.org/View/2169798</link>
      <description><![CDATA[It is well-established that precursor movement that precedes large rockfalls can be detected by monitoring using repeated laser scanning (i.e., lidar), but there is a lack of documented cases that illustrate the practical application of this technology to forecast and help prevent large rockfalls along transportation corridors. In this paper, we present a case study in which routine lidar monitoring allowed a large (~30 m3, ~1050 ft3) moving block of rock to be detected before failure. Analysis of the lidar data allowed for historical movement to be evaluated, time to failure to be estimated, and quantification of the geometric and structural data necessary to design an effective mitigation scheme. The block movement was interpreted to be associated primarily with a planar sliding mechanism, and a limit equilibrium analysis was conducted to evaluate potential reinforcement schemes. Ultimately, a mesh and pattern bolt reinforcement system was installed. During rockbolt tensioning, PVC extensometers installed by the contractor showed closure of the fracture at the back of the block.]]></description>
      <pubDate>Thu, 11 May 2023 13:20:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2169798</guid>
    </item>
    <item>
      <title>Time-Dependent Solutions for Lined Circular Tunnels Considering Rockbolts Reinforcement and Face Advancement Effects</title>
      <link>https://trid.trb.org/View/1869032</link>
      <description><![CDATA[During deep excavation in weak rock masses, the time-dependent deformation of the rock and longitudinal advancement process have significant influences on the tunnel performance. Accordingly, a combined support system consisting of rockbolts and linings is commonly used in such tunnels to ensure their stability. However, there are no well-established solutions for quickly and accurately evaluating the safety of those support systems. To address this problem, mechanical model of a circular tunnel with a rockbolt–lining combined system is analytically built in this study. Then mathematical formulas for the stresses and displacements around the tunnel are derived, considering the time-dependent behaviors of the rocks and tunnel face advancement effect. Furthermore, the analytical formula proposed in this study is compared with existing solutions and numerical results obtained using the finite-element software Abaqus, and a good agreement is achieved. Finally, a parametric investigation is conducted regarding the influences on the tunnel’s mechanical performance. The results show that the installation time (t0) and distribution density of rockbolts (SθSz) and the installation time of the lining (t1) have a significant influence on the deformation of the surrounding rock. Although the installation times of bolt and lining are positively related to the deformation suppression effect of the surrounding rock, they are negatively related to the stress of the bolt and lining. It is found that the closer the installation time of bolt and lining, the greater the stress of lining; otherwise, the greater the stress of bolts. Furthermore, the initial release coefficient (m) and the ratio of tunnel excavation rate to influence radius can influence the deformation rate of surrounding rock. Finally, the study proposes a new method for quickly evaluating the viscoelastic deformation of a tunnel.]]></description>
      <pubDate>Wed, 22 Sep 2021 12:03:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/1869032</guid>
    </item>
    <item>
      <title>Experimental Investigation of the Mechanical Properties of Sandstone–Coal–Bolt Specimens with Different Angles under Conventional Triaxial Compression</title>
      <link>https://trid.trb.org/View/1841398</link>
      <description><![CDATA[The complex nonlinear mechanical behavior of the combined system of rock and coal surrounding mine openings is a major obstacle for excavation, stability, and support design in mining thin coal seams. In this paper, the triaxial compression failure characteristics and mechanical response of sandstone–coal (SC) specimens with different combination angles are determined. In addition, the influence of the anchor bolt on the mechanical properties of SC specimens is also considered. The results show that the mechanical parameters of the SC and sandstone–coal–bolt (SCB) specimens are different from those of other intact rocks and are substantially affected by the angle. The peak axial strain and triaxial compressive strength (TCS) of the specimens decreased with increasing angles. To comprehensively analyze the phase mechanical characteristics of the specimens and the differences between them, the authors also established the crack initiation stress index (CI) and crack damage stress index (CD) to evaluate the specimen fracture process. The established stress indices CI and CD can accurately describe the roles of the bolt and angle of the SC and SCB specimens. The bolt can enhance the mechanical properties of the SC specimen after reaching the peak load, restrain the development of cracks, and ensure that the specimen maintains integrity. It should be noted that this type of SCB system is in line with the long-term stability of roadway support engineering applications.]]></description>
      <pubDate>Wed, 21 Apr 2021 16:17:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1841398</guid>
    </item>
    <item>
      <title>Case Studies in Roadway Landslide Repair and Rock Slope Stabilization in California</title>
      <link>https://trid.trb.org/View/1503028</link>
      <description><![CDATA[The challenges associated with roadway landslide and rock slope failures along California’s roadways can introduce a series of difficult problems to solve. Not only is the design and construction associated with the repair of these landslides and rock slope failures challenging, many of the traditional contracting and review processes available either present too long of a time frame or are not flexible enough to handle the field level decisions often required with emergency landslide and rock slope repairs. This paper outlines some landslide and rock slope design build mitigation methods and technologies that are both relatively lower cost when compared to traditional repairs methods and robust enough to achieve standard design life and seismic criteria. Relevant technologies include soil nailing (including hollow injection anchors), high capacity tensioned wire rock mesh, micropiles, post-tensioned rock bolts, and various types of drilled horizontal drains. The case studies for this presentation include a rock slope stabilization using tensioned rock bolts and high capacity wire mesh for the United States Army Corps near Chowchilla, CA; a Pacific coast bluff repair using hollow bar soil nails, micropiles, and shotcrete for California Department of Transportation (CalTrans) District 4 near Pescadero, CA; a landslide repair using self drilling soil nails, micropiles and shotcrete for CalTrans District 2 near Weaverville, CA; and a landslide repair using self drilling soil nails and shotcrete for Santa Clara County Public Works near Los Gatos, CA, and a series of landslides repaired using an innovative combination of the “Deep Patch” method and micropiles for the USDA Forest Service near Fresno, CA.]]></description>
      <pubDate>Wed, 28 Feb 2018 09:34:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/1503028</guid>
    </item>
    <item>
      <title>Analytical Solution for Bolted Tunnels in Expansive Loess Using the Convergence-Confinement Method</title>
      <link>https://trid.trb.org/View/1486811</link>
      <description><![CDATA[Ground reinforcement using bolts is effective for underground excavations. The ground response of expansive loess tunnels with bolt reinforcement remains poorly understood. Therefore, this paper proposes an analytical solution for bolted rock in expansive ground using the convergence-confinement method. On the basis of the bilinear strength criterion for rock mass, a computational procedure was used to obtain the ground reaction curve (GRC) for expansive loess tunnels with bolt reinforcement. The proposed approach considers ground expansion stress and geometrical parameters, mechanical parameters, and pretension of bolts. The results confirm the positive influence of bolt reinforcement and the negative influence of expansion stress on the GRC. Bolt reinforcement offers good resistance against harmful expansion stress and improves the overall stability of loess tunnels. When the expansion stress of an expansive loess tunnel reaches a certain limit, bolt reinforcement is necessary for tunnel stability. This critical limiting value of the expansion stress can be evaluated using the proposed approach. The proposed analytical solution provides guidelines for the stability estimation of tunnel excavations in expansive ground.]]></description>
      <pubDate>Wed, 27 Dec 2017 10:24:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/1486811</guid>
    </item>
    <item>
      <title>Case Studies on Rockfall Mitigation and Rock Slope Stabilization in California, Tennessee, Virginia, and Vermont</title>
      <link>https://trid.trb.org/View/1480113</link>
      <description><![CDATA[Rockfall constitutes a major hazard along the nation’s roadways and a nagging liability to the maintenance and engineering departments. Recurring cleanup and repair costs have stressed dwindling maintenance budgets. The extensive nature of the problem precludes repairing and mitigating every possible site, but new and innovative mitigation technologies and contracting techniques can serve to stretch tight budgets. There are many methods that can be used to stabilize a rock slope. These include altering the slope geometry, installing drains, adding reinforcement, or a combination of these methods. The challenge for engineers is to design a method that can be installed with little or no impact to the traveling public, is expedited through innovative contracting methods, limits the disturbance to environmentally sensitive areas, and maintains an aesthetically pleasant appearance and appropriate service life. This presentation covers four case studies that highlight innovative technology and innovative contracting methods for rockfall mitigation. The case studies include a project for the United States Army Corps of Engineers near Chowchilla, CA using design/build/warranty contracting and post-tensioned rock bolts with Maccaferri B600 mesh facing; a project for the Tennessee Department of Transportation near Maryville, TN using rock dowels and Geobrugg’s high-capacity Tecco® mesh facing; a design/build project for the Virginia Department of Transportation near Hillsville, VA using a shear dowel array encased in reinforced shotcrete overlying a drilled drainage array; and an emergency design/build rockfall mitigation project for the Vermont Agency of Transportation that used a shear key, scaling, vegetation removal, rock dowels, and both wet and dry mix shotcrete.]]></description>
      <pubDate>Thu, 24 Aug 2017 09:46:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1480113</guid>
    </item>
    <item>
      <title>Flexible Rockfall Mitigation Design for Varying Site Conditions</title>
      <link>https://trid.trb.org/View/1473990</link>
      <description><![CDATA[Perry County, Pennsylvania is the location of the longest stone masonry arch railroad viaduct in the world. To provide sandstone blocks needed for bridge construction, quarries were developed near the bridge. A road was later constructed at the base of the quarry highwalls in the 1930s which later became U.S. Route 11, a heavily-traveled commuter highway. Soon after highway construction, rockfall hazards to the highway developed. At the time of construction, rockfall mitigation from the highly fractured, sandstone highwall was not considered. In 2015, the Pennsylvania Department of Transportation (PENNDOT) retained a local geotechnical engineering company to perform the initial site investigation, analyses, and preliminary mitigation design. Following the project bid award, the contractor was required to retain a consultant engineer specializing in rockfall mitigation. The engineer’s responsibility was to finalize the mitigation design following clearing of the vegetation and scaling. The engineer then provided daily construction oversight which allowed design modifications to be made quickly and efficiently. The engineer and contractor could implement in-field changes as construction proceeded. Due to the highway closure, a strict deadline of forty days to complete the construction was put in place. Open and rapid communication between all parties allowed the project to be completed within time constraints. In addition, the formation of a team of the most qualified contractors and geohazard specialists available created the optimal environment for a successful project.]]></description>
      <pubDate>Mon, 31 Jul 2017 16:36:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/1473990</guid>
    </item>
    <item>
      <title>Rock Bolting in Sensitive Environments: Preview of an Upcoming FHWA Federal Lands Guidance Manual</title>
      <link>https://trid.trb.org/View/1472673</link>
      <description><![CDATA[Rock bolts are routinely used throughout the United States to improve the stability of natural rock slopes and cut slopes in rock adjacent to roadways, including on low volume roads in sensitive environments such as Federal Lands Highway (FLH) projects. Several existing manuals address the design and installation of rock bolts. However, these manuals are generally geared toward high volume roads where public safety and cost are the primary project objectives. While FLH projects recognize the importance of safety and cost, the overall goals of the projects are unique because of the major concerns with aesthetics, construction impacts, and maintenance. In addition, the level of acceptable risk for low volume roads may vary from those for a high volume divided highway. To address these concerns, the Central Federal Lands Division of the FHWA has commissioned development of a rock bolting manual. Specifically, it will address project planning, design, construction, inspection, testing, and maintenance in a format that considers the unique FLH project goals. While the manual is being prepared specifically for use on projects administered by Federal Lands Management Agencies (ex. National Parks and Forests), the authors anticipate that it can be used by other agencies that own, build, and maintain low volume roads, such as state and local park agencies. The manual will be available in late 2014 or early 2015, and this presentation will provide an overview of the manual while highlighting methods of dealing with the unique challenges of rock slope stabilization in sensitive environments.]]></description>
      <pubDate>Wed, 05 Jul 2017 09:36:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/1472673</guid>
    </item>
    <item>
      <title>Using New and Old Technologies for an Economical Approach to Rock Stabilization on TN I-75</title>
      <link>https://trid.trb.org/View/1471962</link>
      <description><![CDATA[The Highway & Mining industries have historically used benches as an effective technique for rockfall mitigation as described in The Transportation Research Board’s “Rockfall: Characterization and Control” handbook. This paper describes how the latest advances in rockfall technology can be coupled with the older technique of benching to effectively and economically mitigate a rock slope along I-75 in Tennessee, north of Knoxville and close to the Tennessee / Kentucky border. By rehabilitating the existing benches, scaling off the loose rock in critical areas, using pinned mesh, a mesh drape, and rock bolts, the Tennessee Department of Transportation (TNDOT) was successful in mitigating this near vertical rock slope that is over 200 feet high and almost two miles long. This paper will focus on the approach and design parameters utilized to develop this innovative and economical approach. In addition, this paper will explain the thought process involved, tools utilized, construction sequence, and traffic control steps needed to complete the project.]]></description>
      <pubDate>Thu, 29 Jun 2017 13:49:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/1471962</guid>
    </item>
    <item>
      <title>Ground Anchor Selection and Testing – Matching Ground Anchors to Their Desired Function and Testing Their Serviceability</title>
      <link>https://trid.trb.org/View/1471831</link>
      <description><![CDATA[Ground anchor installations cover a broad range of uses from simple tiedown anchors used for telephone pole support cables to multi-strand tendons used for dam tiedowns that carry millions of pounds of tension. Many of the principles of grout to rock/soil bond and mobilized soil/rock mass volume, weight and strength are common to all types of anchors; however the design elements of different anchor types require specific testing to verify correct installation and functionality of each design element in order to ensure that the constructed ground anchor meets its design requirements and service life. This paper reviews the different types of anchors, anchor materials, types of anchor loading and levels of serviceability for common ground anchors, and discusses the need to tailor construction verification testing to suit different anchor types, function, and serviceability requirements.]]></description>
      <pubDate>Thu, 29 Jun 2017 13:49:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/1471831</guid>
    </item>
    <item>
      <title>Case Histories On Light Anchor Post System For Flexible Barriers</title>
      <link>https://trid.trb.org/View/1471953</link>
      <description><![CDATA[Geohazard mitigation has a well-established testing guideline for flexible fence for rockfall protection, like the European testing guideline ETAG 027 or the USA guideline NCHRP 20-07 Recommended Procedures for the Testing of Rockfall Barriers. These two test procedures describe very well the functionality of a rockfall barrier and describe all the steps necessary to carry out a full scale test and consequently outline the deformability, resistance, performance and forces acting on the anchor post system of a deformable rockfall fence. The anchor post system (foundation) is not considered as part of these testing guidelines. Designers must design the anchoring system considering the different national standards and the geotechnical characteristics of the site. Oftentimes problems arise from the post anchor system, due to remote access to site locations. Not only does a remote location interfere with the operation of heavy machinery, but transportation is also very difficult. In these situations, the anchor post system can become more expensive than the fence itself, which could result with a rejection of the rockfall barrier, due to the high global cost of the intervention. When a severe rock impact damages a barrier, for safety reasons, a large portion of the structure must be replaced and oftentimes the anchoring system should also be replaced. Then the question becomes whether or not heavy anchor post systems make sense. This paper presents case studies of Maccaferri rockfall barriers impacted by several blocks. Even though the fences were installed with unusual light post anchoring systems, the fences were able to withstand impacts exceeding their nominal capacity. The analysis of the structure suggests that in certain conditions, displacement and settlement on the anchor post systems represent a benefit.]]></description>
      <pubDate>Thu, 29 Jun 2017 13:49:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/1471953</guid>
    </item>
    <item>
      <title>Improving Rockbolt Design in Tunnels Using Topology Optimization</title>
      <link>https://trid.trb.org/View/1353149</link>
      <description><![CDATA[Finding an optimum reinforcement layout for underground excavation can result in a safer and more economical design, and is therefore highly desirable. Some works in the literature have applied topology optimization in tunnel reinforcement design in which reinforced rock is modeled as homogenized isotropic material. Optimization results, therefore, do not clearly show reinforcement distributions, leading to difficulties in explaining the final outcomes. To overcome this deficiency, a more sophisticated modeling technique in which reinforcements are explicitly modeled as truss elements embedded in rock mass media is used. An optimization algorithm extending the solid isotropic material with penalization method is introduced to seek for an optimal bolt layout. To obtain the stiffest structure with a given amount of reinforced material, external work along the opening is selected as the objective function with a constraint on the volume of reinforcement. The presented technique does not depend on material models used for rock and reinforcements and can be applied to any material model. Nonlinear material behavior of rock and reinforcement is considered in this work. Through solving some typical examples, the proposed approach is proved to enhance the conventional reinforcement design and provide clear and practical reinforcement layouts.]]></description>
      <pubDate>Thu, 28 May 2015 09:24:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/1353149</guid>
    </item>
    <item>
      <title>Practical Method for the Design of Pretensioned Fully Grouted Rockbolts in Tunnels</title>
      <link>https://trid.trb.org/View/1352347</link>
      <description><![CDATA[This study develops an analytical approach to quantitatively model the efficiency of the pretensioning of grouted rockbolts in terms of reduction of tunnel convergence. In this study, the distribution of force along the pretensioned fully grouted bolt is calculated by the assumption of a rigid connection between the bolt and the rock mass. A compressive force is then applied to the bolt head on the tunnel surface to consider the shear relative displacement between the bolt and the rock mass. The magnitude of this compressive force is found by modeling the bolt boundaries’ stiffness. The theoretical proposed approach is simplified to be used for practical purposes. The results show that if the stiff end plate is tightened to the bolt head (complete planner contact), the grouting effect of the pretensioned fully grouted bolts on tunnel stability can be neglected.]]></description>
      <pubDate>Thu, 28 May 2015 09:23:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/1352347</guid>
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