1 / 20

CT5806701 Reinforced Earth Structures

CT5806701 Reinforced Earth Structures. Construction of MSE Structures. National Taiwan University of Science and Technology Department of Construction Engineering Professor Kuo-Hsin Yang. Construction of MSE Walls. Facing. Reinforcement. Backfill. Drainage. Construction Procedure.

leighanna
Download Presentation

CT5806701 Reinforced Earth Structures

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CT5806701Reinforced Earth Structures Construction of MSE Structures National Taiwan University of Science and Technology Department of Construction Engineering Professor Kuo-Hsin Yang

  2. Construction of MSE Walls Facing Reinforcement Backfill Drainage

  3. Construction Procedure Ground Preparation Survey and Level Ground Weak ground will induce large deformation and reinforcement load Construction Foundation Place Reinforcement, Facing Element, Backfill Compaction NG Field Compaction Check OK Construction Drainage System Reach Design High OK Erosion Control. Vegetation

  4. Construction Procedure Ground Preparation Survey

  5. Construction Procedure Construction (RC) Foundation For weak ground, sometimes need use pile foundation Place first layer of reinforcement

  6. Construction Procedure Place backfill, facing elements

  7. Construction Procedure Compaction, Hand Compaction when close to facing to reduce facing deformation

  8. Construction Procedure NG Sand Cone Method (ASTM D1556) Nuclear Method (Nuclear Density Meter) Check field compact for every 1000m2

  9. Construction Procedure Drainage(+Filter) Systems

  10. Other Important Issues • Backfill • Drainage System • Compaction Most of time, MSE structures fail due to three issues above rather than incorrect design methods (stability analysis)

  11. Other Important Issues • Koerner and Koerner (2011) studied a total of 82 failure cases • (excessive deformation 23 cases and total collapse 59 cases). • 86% failed in less than four years • 76% used silt and clay backfill soils • only 20% had good compaction • 68%of the failures were caused by internal or external water Koerner, R. and Koerner G., (2011) “The Importance of Drainage Control for Geosynthetic Reinforced Mechanically Stabilized Earth Walls”, Journal of GeoEngineering, 6(1), pp.3-13

  12. Selection of Backfill FHWA for Walls FHWA for Slopes Cu≥4 less restrict for slope Dmax<19mm Use granular soil as backfill (high shear strength, low earth pressure, high permeability)

  13. Backfill Material Local Soil Local Soil Backfill Material Backfill Material

  14. Drainage System To avoid accumulation of pore water pressure and internal erosion of backfill (piping) Drainage Layer

  15. Drainage System

  16. Drainage System Intermittent Drainage Layer Blanket Drain Front View

  17. What is Wrong?

  18. Failure Progression due to Water Pressure

  19. Failure Progression due to Water Pressure Facing Deformation Tension Cracks Internal Erosion

  20. Compaction Increase backfill relative density, shear strength and reduce deformation • wopt ±2％ • gd, field ≥90％gd,max(AASHTO T180) • Compaction layer <30cm • Within a distance of 1.5m from facing, use hand compaction or small compaction machine (less than 1ton) to reduce facing deformation

More Related