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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>
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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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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Field Verification of Undercut Criteria and Alternatives for Subgrade Stabilization – Coastal Plain</title>
      <link>https://trid.trb.org/View/1164729</link>
      <description><![CDATA[The North Carolina Department of Transportation (NCDOT) is progressing toward developing quantitative and systematic criteria that address the implementation of undercutting as a subgrade stabilization measure. As part of this effort, a laboratory study and numerical analysis were performed from 2008 to 2010 with the results providing proposed criteria for undercutting under various roadway site conditions and the adequacy of stabilization measures typically employed if undercut was deemed necessary. These criteria provide provisions for discerning possible rutting and pumping of the subgrade under construction loading, and provide response and subgrade stiffness under repeated loading of 10,000 cycles. The work in this report is focused on performing full-scale testing in the field on instrumented unpaved roadway sections to collect data for the validation of guidelines developed from the laboratory and modeling study. Four 16 feet wide by 50 feet long stabilized test sections were built on poor subgrade soils encountered in the Coastal Plain region of North Carolina. One test section encompassed undercutting and replacement with select material (Class II), the second and third test sections included reinforcement using a geogrid and geotextile, respectively, in conjunction with undercutting and replacement with ABC (Class IV), and a fourth test section included cement treatment of the soft subgrade soil. Full-scale testing was conducted on the test pad by applying 1000 consecutive truck passes using a fully loaded tandem-axle dump truck over a period of four days. During this time visual observations were noted and measurements were collected regarding rut depth, vertical stress increase at the base/subgrade interface, and subgrade moisture content with truck passes. Once trafficking was completed, the test pad was re-graded and proof roll testing was performed to look for signs of pumping and rutting. Based on the field results, the proposed undercut criteria are evaluated in regards to the ability to discern the need for undercutting as well as predict the performance of the stabilized test sections. Finally, a performance cost analysis is conducted to illustrate the relative cost of each stabilization measure in relation to the measured performance (rutting) such that an informed decision on cost-effective subgrade stabilization can be made.]]></description>
      <pubDate>Fri, 24 Aug 2012 09:46:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1164729</guid>
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      <title>Field Experiment of Subgrade Vibration Induced by Passing Train in a Seasonally Frozen Region of Daqing</title>
      <link>https://trid.trb.org/View/890853</link>
      <description><![CDATA[The vibration characteristics and attenuation of the subgrade caused by passing trains in a seasonally frozen region of Daqing, China, are investigated. Three field experiments were conducted during different times through the year, in normal, freezing, and thawing periods, respectively, and the influence of the season, train speed and train type, is described in this paper. The results show that: 1) the vertical component is the greatest among the 3 components of the measured vibration near the rail track, and as the distance to the railway track increases, the dominant vibration depends on the season; 2) compared with the vibration in the normal period, the vertical and longitudinal vibrations increase while the lateral vibration decreases in the freezing period, however, in the thawing period, the vertical and longitudinal vibrations decrease, and the lateral vibration increases; 3) as train speeds increase, the subgrade vibration increases; and 4) the vibration induced by a freight train is greater than by a passenger train. These observations provide a better understanding of the vibration and dynamic stability of the subgrade and may be useful in developing criteria for railway and building construction in cold regions.]]></description>
      <pubDate>Mon, 22 Jun 2009 14:01:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/890853</guid>
    </item>
    <item>
      <title>Guide to Full-Depth Reclamation (FDR) with Cement</title>
      <link>https://trid.trb.org/View/887589</link>
      <description><![CDATA[This publication is a revised and more current comprehensive guide to full-depth reclamation (FDR) using cement. FDR is a roadway rehabilitation process that recycles the materials from deteriorated asphalt pavement, and, with the addition of portland cement, creates a new stabilized base. The addition of a new concrete or bituminous riding surface completes the FDR process, providing a new roadway structure using recycled materials from the failed pavement. The FDR process is described in a step-by-step manner, from initial site investigation to mix design and construction. A recommended construction specification for FDR is included.]]></description>
      <pubDate>Tue, 14 Apr 2009 11:52:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/887589</guid>
    </item>
    <item>
      <title>2D Finite Element Analysis to Evaluate the Performance of Geogrid Base Reinforcement in Weak Flexible Pavement Structures</title>
      <link>https://trid.trb.org/View/886624</link>
      <description><![CDATA[Two dimensional (2-D) axisymmetric finite element analyses (FEA) were conducted on different pavement sections to assess the advantages of reinforcing the base course layer with geogrids and to evaluate the effects of subgrade strength, thickness of the base course layer, and stiffness and location of the geogrid on these sections. The surface permanent deformations of the first 100 load cycles were obtained from the FEA and used to develop regression models that relate the permanent deformation with load cycles for the different pavement sections. The permanent deformation at 2 million load cycles was then determined and selected as a criterion for evaluating the influence of the different variables on the performance of geogrid reinforced pavement sections. The results indicate that for base course layers with thicknesses between 150-254 mm, the optimum location was always at the bottom of the base layer. At this location, the improvements found in weak subgrades were always superior to those found in stiffer ones. In addition, the improvements were reduced as the thickness of the base layer increased and were enhanced as the stiffness of the geogrid layer increased. Multiple regression analyses were also conducted to develop models to predict the Base Course Reduction (BCR) factor in terms of subgrade strength, reinforced base thickness, and geogrid stiffness. Further FEA were conducted to verify the developed regression models. The results showed that the developed regression models yielded good predictions of the BCR values.]]></description>
      <pubDate>Mon, 13 Apr 2009 14:58:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/886624</guid>
    </item>
    <item>
      <title>Investigation of the Domestic Applicability of the Density Measuring Technique Based on Dielectricity for Earthworks</title>
      <link>https://trid.trb.org/View/879151</link>
      <description><![CDATA[This paper on methods to investigate earthwork (subgrade) density is part of the research carried out by the Institute for Transport Studies, Hungary, in 2007.  The author notes that the present technique of radiometer subgrade density measurement used in Hungary is not likely to be used in the near future, due to its needs for elaborate storage, transport and operation, stricter rules, and concerns about radiation emission.  The author then reports on a study undertaken to investigate the applicability of a subgrade soil density measuring device that has been widely used in the United States.  This newer measuring method determines the changes in dielectric constant and electrical conductivity, then calculates the parameters of soil quality using some characteristics of the soil, including moisture content ranges.  The device used has to be calibrated for the actual soil before starting the measurement.  The author reports on the reliability and repeatability of the test measurements, as investigated in both laboratory and field uses.  The author concludes that the measuring device investigated can be appropriate for the density measurement of subgrades; however, it does not seem to be appropriate for every soil type.]]></description>
      <pubDate>Fri, 30 Jan 2009 07:39:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/879151</guid>
    </item>
    <item>
      <title>Experimental Research on Lateral Restricted Swelling Strain of Expansive Soil</title>
      <link>https://trid.trb.org/View/871001</link>
      <description><![CDATA[In this research, mechanical and deformation characteristics of expansive soil specimens subjected to lateral restricted loaded experiment were analyzed by related theory of elastic mechanics. A formula for calculating swelling coefficient of expansive soils was derived under conditions of non-loaded experimentation. In succession, a formula for calculating the lateral loaded swelling ratio of expansive soils varying with moisture content and upper load was established by conducting a lateral restricted loaded swelling experiment. Results show that, upper loads can restrict swelling deformation, while the other conditions unchanged, the greater the upper loads, the smaller the swelling ratio; expansive soil is sensitive to change of water content, which is a direct cause of soil swelling strain generation; and loaded swelling ratio is closely related to absorption moisture content. Lastly, a measuring method of coefficient of moisture swelling was established by adopting lateral restricted non-loaded swelling experiment in light of expansive soils in a selected road section, and recommendations are put forward for embankment construction of the road.]]></description>
      <pubDate>Wed, 24 Sep 2008 10:37:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/871001</guid>
    </item>
    <item>
      <title>Final Report: Subgrade Stability</title>
      <link>https://trid.trb.org/View/860512</link>
      <description><![CDATA[Subgrade stability is a term which relates to the strength and deformation properties of the soil.  Both properties significantly influence 1) the response of a subgrade to the heavy repeated loading of construction traffic and operations, 2) the ability to place and compact overlying material layers, and 3) the long-term performance of the pavement subgrade.  Ideally the subgrade should be strong enough to prevent excessive rutting and shoving, and sufficiently stiff to minimize resilient deflection.  In this report a) concepts for characterizing field subgrade stability conditions are developed; b) subgrade stability requirements are established for construction (sinkage and compaction considerations); c) remedial actions (undercut and backfill, moisture-density control, lime treatment of subgrades) for inadequate subgrade stability conditions are described and evaluated; and d) assessment guidelines for considering which remedial procedure(s) should be used for a particular situation are presented.  Moisture-density-CBR (California bearing ratio) data for five typical Illinois soils are presented in Appendix A.  Appendix B presents a documented hypothesis describing the mechanism of subgrade softening under conditions of high moisture content and heavy repeated loading.]]></description>
      <pubDate>Thu, 12 Jun 2008 09:57:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/860512</guid>
    </item>
    <item>
      <title>METHOD FOR RAILROAD TRACK FOUNDATION DESIGN. I: DEVELOPMENT</title>
      <link>https://trid.trb.org/View/485957</link>
      <description><![CDATA[This paper presents the development of a new design method for selecting granular layer thickness for railroad track.  Design of an adequate granular layer thickness is intended to prevent two common railroad subgrade failures caused by repeated traffic loading.  One type of subgrade failure is progressive shear failure, and the other is excessive plastic deformation.  The design is based on limiting traffic load-induced deviator stress in the subgrade, which represents the combined influence of both vertical and confining stresses, to levels producing acceptable subgrade performance.  The new method has significant advantages over existing methods.  These advantages include the way in which traffic is characterized, the multilayer representation of the track structure, and emphasis on subgrade performance under repeated loading.  Design charts developed cover various soil and granular layer conditions.  The soil and granular properties considered include resilient modulus, soil compressive strength, and soil type.  The traffic is characterized by the dynamic wheel loads and the total equivalent number of repeated load applications for the design period.]]></description>
      <pubDate>Sat, 09 May 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/485957</guid>
    </item>
    <item>
      <title>GEOSYNTHETICS '91. CONFERENCE PROCEEDINGS. VOLUME 2</title>
      <link>https://trid.trb.org/View/389089</link>
      <description><![CDATA[This is a presentation of the papers presented at the above conference in five categories.  The category of Failures and Solutions includes papers covering geogrid reinforced retaining wall backfilled with cohesive soil; a shattered geomembrane; and geosynthetics on compressible clays.  The category on Technical Advancements/Testing and Research, includes papers on laboratory tests on geotextile/bentonite liner; load test of geotextile reinforced retaining wall; comparison of geosynthetic soil walls; creep in polymeric reinforcement; metal and tensar geogrid strips; polymeric geogrid performance; nonwoven geotextile; pullout tests; geogrids with low junction efficiency; and repeated traffic loading on geosynthetic reinforcement anchorage resistance.  The category on Transportation Applications includes papers on geogrid reinforcement and stabilization of a highway subgrade; geogrid earth reinforced retaining wall response; geotextiles for subgrade stabilization; and geosynthetic moisture barrier.  The category on Heavy Construction Applications includes papers on geotextile for stabilizing mudstone slope; geotextile wall; geogrid reinforced soil wall bridge; soil retaining walls; and reinforcement of failed embankment on slough mud.  The Commercial/Industrial Applications category includes papers on surcharge embankments; design for silt fences; modular block faced polymer geogrid reinforced soil walls; 18- foot high geogrid stayed concrete block wall; geogrid reinforced soil-cement arch; and modular concrete retaining wall and geogrid reinforcement.]]></description>
      <pubDate>Fri, 25 Mar 1994 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/389089</guid>
    </item>
    <item>
      <title>OPTIMUM ADAPTATION OF THE CONVENTIONAL TRACK TO FUTURE TRAFFIC. PERFORMANCE OF SOIL UNDER THE EFFECT OF REPETITIVE STRESSES AS A FUNCTION OF PARTICLE SIZE AND WATER CONTENT</title>
      <link>https://trid.trb.org/View/15597</link>
      <description><![CDATA[The present report summarizes the results of tests in connection with the performance of various soils under the influence of different water content conditions and under the effect of repetitive stresses.  This enables a better assessment to be made of the performance of track bed structures and of soil in the railway subgrade under the effect of fatigue loading and various climatic conditions.]]></description>
      <pubDate>Wed, 28 Oct 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/15597</guid>
    </item>
    <item>
      <title>OPTIMUM ADAPTATION OF THE CONVENTIONAL TRACK TO FUTURE TRAFFIC. THE INFLUENCE OF FROST ON THE FOUNDATION OF RAILWAYS: DESIGN OF PROTECTIVE MEASURES</title>
      <link>https://trid.trb.org/View/15598</link>
      <description><![CDATA[This report describes the criteria for evaluating the susceptibility of various soils with respect to phenomena due to frost and, using theoretical and experimental studies as a basis, it specifies the protective measures to be taken mainly as regards sub-structure depths.]]></description>
      <pubDate>Wed, 28 Oct 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/15598</guid>
    </item>
    <item>
      <title>SOILS-BALLAST-GEOTEXTILE RELATIONSHIP: PART 2--THE FABRIC FACTOR</title>
      <link>https://trid.trb.org/View/168123</link>
      <description><![CDATA[The ballast-subgrade system should provide uniform track support, free from excessive permanent deformation, while also maintaining a resiliency within acceptable predetermined limits.  Resiliency will allow the ties to move with, rather than within, the ballast and avoid abrasive wear which shortens tie life.  The author explains how geotextiles assure the long-term resiliency of ballast and subgrade by excluding excessive moisture and by providing drainage paths that assure lateral water flow. Fabrics also stabilize track structures when tensioned so ballast particles are restrained to act as a unit and offer a positive separation of ballast and subgrade materials.  No single fabric function or fabric weight can be considered to be a universal geotextile.]]></description>
      <pubDate>Thu, 09 Jul 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/168123</guid>
    </item>
    <item>
      <title>SOME EXPERIENCE GAINED BY NETHERLANDS RAILWAYS IN USING THE DYNAMIC TRACK STABILIZER</title>
      <link>https://trid.trb.org/View/166842</link>
      <description><![CDATA[The paper reports on experience gained by Netherlands Railways (NS) in the past three years in the use of the dynamic track stabilizer developed by Plasser & Theurer, Vienna.  NS have employed the dynamic track stabilizer mainly with the intention to increase the lateral strength immediately after renewal and tamping work.  A few test results are discussed, namely measurements of the resistance to transverse shifting and measurements of the subsoil vibration propagation due to stabilization. Moreover, results on the track geometry of stabilized and non-stabilized track sections are compared.]]></description>
      <pubDate>Fri, 12 Jun 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/166842</guid>
    </item>
    <item>
      <title>OPTIMUM ADAPTATION OF THE CONVENTIONAL TRACK TO FUTURE TRAFFIC. HYDRAULIC PERFORMANCE OF TRACK BED STRUCTURES AND SOIL UNDER THE INFLUENCE OF RAINFALL</title>
      <link>https://trid.trb.org/View/15556</link>
      <description><![CDATA[The present report summarises the results of tests by the SNCF in connection with the hydraulic performance of track bed structures and soil under the effect of rainfall.  It ends with some practical conclusions as regards the dimensioning of longitudinal drainage systems. Parallel with other investigations in progress, it evaluates the water content conditions to be taken into account under various climatic conditions.]]></description>
      <pubDate>Fri, 06 Feb 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/15556</guid>
    </item>
    <item>
      <title>OPTIMUM ADAPTATION OF THE CONVENTIONAL TRACK TO FUTURE TRAFFIC. STABILISATION OF BALLAST BY CHEMICAL METHODS</title>
      <link>https://trid.trb.org/View/15516</link>
      <description><![CDATA[This report presents results of tests carried out to determine the effectiveness of ballast stabilisation by chemical gluing methods.  These tests were carried out by BR, DB, SJ and SBB.  Results of earlier tests by other Administrations are also given.  (Japan, USA, etc.)]]></description>
      <pubDate>Wed, 19 Dec 1979 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/15516</guid>
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