Hybrid A-Frame Micropile-Geosythetic Reinforced Wall With Impact Barrier: Design Development and Construction Approach

Details

• Creators:
  Pak, Ronald Y. S. ; Zhang, Zhichao
• Corporate Creators:
  University of Colorado Boulder
• Corporate Contributors:
  Colorado Department of Transportation. Office of Applied Research ; United States. Department of Transportation. Federal Highway Administration
• Subject/TRT Terms:
  Deformation Finite Element Method Geosynthetic Reinforced Soil (GRS) Geosynthetics Impact Road Barriers Large Deformation LS-DYNA Mechanically Stabilized Earth Micropiles Safety Factors Slope Stability Soils Traffic Barriers

  More +
• Publication/ Report Number:
  CDOT-2018-11
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Colorado
• Edition:
  Final Report
• Corporate Publisher:
  Colorado Department of Transportation. Applied Research & Innovations Branch
• Abstract:
  This report presents the results of a comprehensive evaluation of a hybrid A-frame micropiles-geosynthetic reinforced soil wall design to support roadways with TL-4 impact road barriers on mountainous roads and its accompanying engineering options in dealing with the foundation stability problems in road widening and construction projects. Extensive numerical simulations of MSE walls were conducted by 3D nonlinear computer modeling using an advanced finite element code and an elastoplastic soil model that has been well calibrated in past NCHRP and CDOT projects. Collaborated partially by an experimental scaled model study that substantiated the general applicability of the modeling platform, the performance of the hybrid design under self-weight, surcharge and dynamic impacts was investigated in detail and compared with that of a truncated GRS wall with regular construction. The available option of using the A-frame micropile as an integrated solution to the related local slope-foundation stability problem that can be triggered by the wall construction was explored and quantified by the large-deformation analysis with the aid of the new threshold effective strain concept whose validity was demonstrated against ordinary limit-equilibrium slope stability methods in benchmark settings. While there remains engineering details to be explored and more realistic representation of material components to be incorporated, the study has shown that the hybrid wall design offers potential as a new or remedial engineering option in coping with difficult hillside or steep terrain conditions for road expansion or new projects. Implementation: The design worksheets should be further evaluated and checked for field construction, monitoring and adaptations. More refined and detailed modeling of the hybrid design's material components beyond the soil and geofabric and the performance of the system at new MASH loads is also strongly recommended.
• Format:
  PDF
• Funding:
  214.03
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:feba4a74fc8d756400564189d839f29ac34d639c44a650b8438abcfb2cf1b65c3cf7d7456f826ca593546c580494e5f47ff764155e189d8c39b545427c4e7472
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/92847/dot_92847_DS1.pdf
• File Type:
  [PDF - 4.87 MB ]