STATIC AND DYNAMIC PROPERTIES OF RAILROAD BALLAST

The paper describes research undertaken to predict elastic and inelastic response of railroad track as related to the properties of the ballast materials. The elastic response involves the resilient modulus from repeated load triaxial tests. The inelastic response involves permanent strain accumulation under repeated load. A key problem in relating laboratory to field conditions was the difficulty in measuring the physical state of the ballast. A three-dimensional computer model of the track structure was used to determine the stresses in the ballast. A method was then proposed for converting these to the triaxial stress states in the laboratory. Apparatus used for performing these tests was described. Then examples of measured properties of ballast were given. The static test results were similar to those for other granular materials. The ballast was essentially elastic after a few hundred cycles, but significant permanent strain continued to accumulate even after thousands of cycles. Measured values of permanent ballast strain in the field were compared to the laboratory results. Approximate agreement was found, but more study is needed to establish a permanent strain prediction approach with confidence. See also IRRD abstract no 250216.

• Supplemental Notes:
  • Sexto Congreso Panamericano de Mecanica de Suelos e Ingenieria de Cimentaciones, Lima, Peru, 2-7 Diciembre 1979.
• Corporate Authors:

  Comision Organizadora del VI CPMSIF

  Apartado Postal 11076
  Lima,   Peru 
• Authors:
  • Alva-hurtado, J
  • Selig, E T
• Publication Date: 1979-12

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 3-17
• Serial:
  • Volume: 2

Subject/Index Terms

• TRT Terms: Ballast (Railroads); Computer programs; Conferences; Deformation; Elasticity (Mechanics); Loads; Mathematical models; Mechanical properties; Modulus of elasticity; Railroad tracks; Repeated loads; Soil mechanics; Statics; Stresses; Test facilities; Train track dynamics; Triaxial shear tests
• Uncontrolled Terms: Models
• Old TRIS Terms: Ballast mechanics; Track response investigations; Track structures
• ITRD Terms: 8525: Conference; 5595: Deformation; 5567: Load; 6205: Model (not math); 5919: Modulus of elasticity; 5588: Repetitive loading; 5755: Soil mechanics; 5433: Statics; 5575: Stress (in material); 5566: Triaxial
• Subject Areas: Geotechnology; Railroads;

Filing Info

• Accession Number: 00325876
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Files: ITRD, TRIS
• Created Date: Feb 18 1981 12:00AM