Railway Ballast Strength and Permeability Affecting Track Performance Under Dry and Wet Conditions

2018 ◽  
Author(s):  
Issam Qamhia ◽  
Maximilian Orihuela ◽  
Scott Schmidt ◽  
Erol Tutumluer ◽  
Maziar Moaveni ◽  
...  
Keyword(s):  
Shear Strength ◽  
Triaxial Test ◽  
Large Scale ◽  
Field Performance ◽  
Test Machine ◽  
Railway Ballast ◽  
Permeability Characteristics ◽  
Strength Tests ◽  
Dry And Wet Conditions ◽  
And Performance

Railway ballast is a major structural component of railroad track that also facilitates the drainage of water. Particle breakage and abrasion due to dynamic loading and environmental impacts causes ballast to age and degrade. The finer materials generated from ballast degradation can adversely affect the track stability especially under wet conditions. This paper investigates through laboratory testing the effect of moisture on the behavior and performance of in-service ballast. The tested ballast samples were initially subjected to an artificial rain system as well as train loadings in the Facility for Accelerated Service Testing (FAST) at the Transportation Technology Center, Inc. (TTCI). The rainy test section experiment applied realistic dynamic freight train loads and continuously monitored the test sections to determine the effects of moisture and saturation conditions on the field performance trends of ballasted track. Accordingly, ballast samples at varying levels of degradation were collected from the test locations to investigate ballast gradations as well as strength and permeability characteristics at dry and wet conditions. Shear strength tests were performed using a large-scale triaxial test machine, known as the TX-24, to study ballast degradation effects on the strength of dry ballast. Materials finer than the 3/8 in. (9.5 mm) were then collected and studied for the moisture-density behavior using a modified Proctor type compactive effort. Shear strength samples with the same gradations and degradation levels were prepared and tested at varying moisture contents of the 3/8 in. (9.5 mm) fraction ranging from 3% to 9%, with the latter being the optimum moisture content of these finer materials. The wet ballast triaxial test samples had strength values only in the range of 38% to 65% of the dry strengths. In addition to the strength tests, constant head permeability tests were also conducted on the ballast samples which demonstrated quite low and negligible horizontal flow amounts through ballast under static pressure heads and at various hydraulic gradients.

scholarly journals Discrete element modelling of railway ballast performance considering particle shape and rolling resistance

2020 ◽  
Vol 28 (4) ◽  
pp. 382-407 ◽  
Author(s):  
Yunlong Guo ◽  
Chunfa Zhao ◽  
Valeri Markine ◽  
Can Shi ◽  
Guoqing Jing ◽  
...  
Keyword(s):  
Shear Strength ◽  
Particle Shape ◽  
Large Scale ◽  
Rolling Resistance ◽  
Discrete Element ◽  
Contact Model ◽  
Discrete Element Modelling ◽  
Railway Ballast ◽  
Contact Models ◽  
Strength And Deformation

AbstractTo simulate ballast performance accurately and efficiently, the input in discrete element models should be carefully selected, including the contact model and applied particle shape. To study the effects of the contact model and applied particle shape on the ballast performance (shear strength and deformation), the direct shear test (DST) model and the large-scale process simulation test (LPST) model were developed on the basis of two types of contact models, namely the rolling resistance linear (RRL) model and the linear contact (LC) model. Particle shapes are differentiated by clumps. A clump is a sphere assembly for one ballast particle. The results show that compared with the typical LC model, the RRL method is more efficient and realistic to predict shear strength results of ballast assemblies in DSTs. In addition, the RRL contact model can also provide accurate vertical and lateral ballast deformation under the cyclic loading in LPSTs.

scholarly journals Railroad ballast behavior in triaxial compression tests with and without geogrid

2019 ◽  
Vol 265 ◽  
pp. 02001
Author(s):  
Andrei Petriaev ◽  
Victor Ganchits
Keyword(s):  
Large Scale ◽  
Triaxial Compression ◽  
Laboratory Studies ◽  
Compression Tests ◽  
Railway Ballast ◽  
Triaxial Apparatus ◽  
Strain Behaviour ◽  
Strength Tests ◽  
Triaxial Compression Tests ◽  
Recent Laboratory

This paper highlights recent laboratory studies at Emperor Alexander I St. Petersburg State Transport University, using large-scale cylindrical triaxial apparatus, which helped quantify the geogrid performance in railway ballast. The triaxial shear strength tests were conducted on ballast with and without geogrid. Effect of geogrid layers quantity on the ballast stress-strain behaviour were studied. The experimental results indicate that the geogrids have improved ballast bearing capacity up to 25%.

scholarly journals Investigation of Salt-Frost Heaving Rules and Mechanical Properties of Chlorite Saline Soil along the Duku Highway under Freezing-Thawing Action

2022 ◽  
Vol 2022 ◽  
pp. 1-12
Author(s):  
Xuebang Huang ◽  
Zizhao Zhang ◽  
Zezhou Guo ◽  
Ruihua Hao ◽  
Qianli Lv ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Large Scale ◽  
Saline Soil ◽  
Physical Property ◽  
Freezing Process ◽  
Composition Analysis ◽  
Frost Heaving ◽  
Starting Point ◽  
Strength Tests

Aiming to investigate salt-frost heaving rules and the mechanical properties of natural saline soil along the Duku Highway subjected to multiple freezing-thawing cycles, we collected natural saline soil samples from the alluvial-proluvial plain in front of the Dushanzi Mountain at the starting point of the Duku Highway. Then, we conducted mineral composition analysis tests, essential laboratory physical property measurement, large scale multiple freezing-thawing cyclic salt-frost heaving tests, shear strength tests, and unconfined compressive strength tests on the samples. According to the test results presented, the collected saline soil differed from saline soil in other regions and fell into “chlorite saline soils.” As the number of freezing-thawing cycles increased, the overall salt-frost heaving capacity increased and then decreased in the freezing process but first reduced and then increased in the thawing process. Thus, the salt-frost heaving capacity was cumulative in freezing/thawing cycles. The peak salt-frost heaving capacity reached a maximum after 1 freezing-thawing cycle and then dropped drastically and fluctuated regularly. After 6 freezing-thawing cycles, the displacement deformation and time formed a new equilibrium. After 7 freezing-thawing cycles, the displacement and deformation of the soil no longer appear negative. As the number of freezing-thawing cycles increased, the cohesive force of saline soil first increased and then dropped steadily, the internal friction angle first dropped and then increased steadily, and the unconfined shear strength first increased and then decreased. These research results provided data supporting the prevention and controlling highway saline soil disasters with insightful references for the other projects in this region.

Performance of two combine harvester header in soybean crops

2020 ◽  
Vol 13 (2) ◽  
pp. 1
Author(s):  
E. M. Samogim ◽  
T. C. Oliveira ◽  
Z. N. Figueiredo ◽  
J. M. B. Vanini
Keyword(s):  
Experimental Design ◽  
Crop Yield ◽  
Field Performance ◽  
Travel Speed ◽  
The Other ◽  
Combine Data ◽  
Mato Grosso ◽  
Tukey Test ◽  
Combine Harvester ◽  
And Performance

The combine harvest for soybean crops market are currently available two types of combine with header or platform, one of conventional with revolving reel with metal or plastic teeth to cause the cut crop to fall into the auger header and the other called "draper" headers that use a fabric or rubber apron instead of a cross auger, there are few test about performance of this combine header for soybean in Mato Grosso State. The aim of this work was to evaluate the soybean harvesting quantitative losses and performance using two types combine header in four travel speed. The experiment was conducted during soybean crops season 2014/15, the farm Tamboril in the municipality of Pontes e Lacerda, State of Mato Grosso. The was used the experimental design of randomized blocks, evaluating four forward harvesting speeds (4 km h-1, 5 km h-1, 6 km h-1 and 7 km h-1), the natural crops losses were analyzed, loss caused by the combine harvester (combine header, internal mechanisms and total losses) and was also estimated the  field performance of each combine. Data were submitted to analysis of variance by F test and compared of the average by Tukey test at 5% probability. The results show the draper header presents a smaller amount of total loss and in most crop yield when compared with the conventional cross auger.

Alban Berg

2017 ◽  
Author(s):  
Helen Abbott
Keyword(s):  
Adhesion Strength ◽  
String Quartet ◽  
Large Scale ◽  
Statistical Data ◽  
Alban Berg ◽  
German Translation ◽  
Stefan George ◽  
Strength Tests ◽  
Parallel Texts

When Austrian composer Alban Berg was working on his opera Lulu, he wrote three Baudelaire songs as a Konzertaria entitled Der Wein. Premiered in 1930, Der Wein is a large-scale work for voice and orchestra. Berg uses a German translation by Stefan George, but the published score is in parallel texts, accommodating the French verse line. The chapter also considers a ‘hidden’ Baudelaire setting from Berg’s 1926 Lyric Suite for string quartet. The analysis covers: (a) the context of composition; (b) the connections established between selected poems; (c) the statistical data generated from the adhesion strength tests; and (d) how the data shape an evaluation of Berg’s settings of Baudelaire. Evidence suggests that Berg’s settings of Baudelaire are loosely entangled; the highly prescriptive score affects syntax, semantics, and prosody. Yet, because Der Wein has stood the test of time, the settings are deemed loosely accretive.

scholarly journals Chitosan-Based Adhesive: Optimization of Tensile Shear Strength in Dry and Wet Conditions

2021 ◽  
Vol 2 (1) ◽  
pp. 110-120
Author(s):  
Maisa Abdelmoula ◽  
Hajer Ben Hlima ◽  
Frédéric Michalet ◽  
Gérard Bourduche ◽  
Jean-Yves Chavant ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Shear Strength ◽  
Bond Strength ◽  
Water Resistance ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Spread Rate ◽  
Assembly Time ◽  
Deacetylation Degree ◽  
Dry And Wet Conditions

Commercial adhesives present a high bond strength and water resistance, but they are considered non-healthier products. Chitosan can be considered as an interesting biosourced and biodegradable alternative, despite its low water resistance. Here, its wood bonding implementation and its tensile shear strength in dry and wet conditions were investigated depending on its structural characteristics. Firstly, the spread rate, open assembly time, drying pressure, drying temperature, and drying time have been determined for two chitosans of European pine double lap specimens. An adhesive solution spread rate of 1000 g·m−2, an open assembly time of 10 min, and a pressure temperature of 55 °C for 105 min led to a bond strength of 2.82 MPa. Secondly, a comparison between a high molecular weight/low deacetylation degree chitosan and a lower molecular weight/higher deacetylation degree chitosan was conducted. Tests were conducted with beech simple lap specimens in accordance with the implementation conditions and the conditioning treatments in wet and dry environments required for thermoplastic wood adhesive standards used in non-structural applications (EN 204 and EN 205). The results clearly revealed the dependence of adhesive properties and water resistance on the structural features of chitosans (molecular weight and deacetylation degree), explaining the heterogeneity of results published notably in this field.

Field Determined Live Load Distribution Factors for Modular Press-Brake-Formed Tub Girders

2021 ◽  
pp. 036119812098375
Author(s):  
Karl E. Barth ◽  
Gregory K. Michaelson ◽  
Adam D. Roh ◽  
Robert M. Tennant
Keyword(s):  
West Virginia ◽  
Experimental Testing ◽  
Field Performance ◽  
Live Load ◽  
Steel Bridge ◽  
Testing Procedures ◽  
Bending Capacity ◽  
Short Span ◽  
And Performance ◽  
Live Load Distribution

This paper is focused on the field performance of a modular press-brake-formed tub girder (PBFTG) system in short span bridge applications. The scope of this project to conduct a live load field test on West Virginia State Project no. S322-37-3.29 00, a bridge utilizing PBFTGs located near Ranger, West Virginia. The modular PBFTG is a shallow trapezoidal box girder cold-formed using press-brakes from standard mill plate widths and thicknesses. A technical working group within the Steel Market Development Institute’s Short Span Steel Bridge Alliance, led by the current authors, was charged with the development of this concept. Research of PBFTGs has included analyzing the flexural bending capacity using experimental testing and analytical methods. This paper presents the experimental testing procedures and performance of a composite PBFTG bridge.

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