Comparisons between analogue and numerical models of thrust wedge development

Analogue and finite element numerical models with frictional and viscous properties are used to model thrust wedge development. Comparison between model types yields valuable information about analogue model evolution, scaling laws and the relative strengths and limitations of the techniques. Both model types show a marked contrast in structural style between ‘frictional-viscous domains’ underlain by a thin viscous layer and purely ‘frictional domains’. Closely spaced thrusts form a narrow and highly asymmetric fold-and-thrust belt in the frictional domain, characterized by in-sequence propagation of forward thrusts. In contrast, the frictional-viscous domain shows a wide and low taper wedge and a thrust belt with a more symmetrical vergence, with both forward and back thrusts. The frictional-viscous domain numerical models show that the viscous layer initially simple shears as deformation propagates along it, while localized deformation resulting in the formation of a pop-up structure occurs in the overlying frictional layers. In both domains, thrust shear zones in the numerical model are generally steeper than the equivalent faults in the analogue model, because the finite element code uses a non-associated plasticity flow law. Nevertheless, the qualitative agreement between analogue and numerical models is encouraging. It shows that the continuum approximation used in numerical models can be used to model frictional materials, such as sand, provided caution is taken to properly scale the experiments, and some of the limitations are taken into account.

Research and development opportunities for improved transportation energy usage. Summary technical report.

Transportation Department, Washington, D.C.

Development of proposed height standards and tolerances for light-post traffic barriers. Interim report.

Federal Highway Administration, Office of Research, Development and Technology, Washington, D.C.

Impact assessment of the Virginia Railway Express Commuter Rail on land use development patterns in northern Virginia.

Federal Transit Administration, Washington, D.C.

Development of a methodology for posting load limits on load-zoned pavements: interim report.

Texas Department of Transportation, Austin

Advanced recorder design and development. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

The development of an improved railroad-highway grade crossing risk factor. Executive summry report.

Ohio Department of Transportation, Columbus

The development of an improved railroad-highway grade crossing risk factor. Final report.

Ohio Department of Transportation, Columbus

The development of UTCS/NETSIM/ICG: an integrated urban traffic control system - network simulation - interactive computer graphics program. Final report.

Transportation Department, Office of University Research, Washington, D.C.

Development and experimental evaluation of a steel tube vehicle impact attenuation system. Final report.

Connecticut Department of Transportation, Bureau of Planning and Research, Wethersfield

The development and evaluation of a prototype grade severity rating system. Final report.

Federal Highway Administration, Washington, D.C.

Development of an automated pre-sampling plan for construction projects. Final report.

Mode of access: Internet.

Development of transit coach bonded brake lining test equipment and test procedures. Progress report. Final report.

Urban Mass Transportation Administration, Washington, D.C.

Development of a methodology for accident causation research. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

UMTA's research and development program should pay closer attention to transit industry needs.

Mode of access: Internet.