Deep Mixing for Support of Approach Embankments for Light Rail Overcrossing in Urban Setting

An aerial structure spanning over a major street was proposed in a heavily developed urban area of Los Angeles as part of a light rail transit project. The project site is underlain by highly compressible clay layers and layers of sandy soils that are susceptible to liquefaction. The surcharge load from the approach embankments was expected to cause excessive settlement that might damage the relatively rigid facing panels of the mechanically stabilized earth (MSE) walls and the improvements to be constructed on top of the embankments. Additionally, major underground utilities, including a 4.4 m (141/2-foot wide) by 5.8 m (19-foot) tall storm drain box and a 4.7 m (151/2-foot) diameter sewer pipeline, were identified in proximity of the MSE walls. The agency that owns the utilities had set a stringent guideline on additional stresses allowed on the underground structures. Mitigation measures were required to reduce the potential for long-term settlement and impact on the existing underground pipelines due to the load from the embankments. The alternatives considered included lightweight fill, lightweight fill supported on structural slab and piles, and ground improvement by deep mixing. This paper presents the evaluation process of these alternatives and successful implementation of deep mixing for support of the approach embankments in an urban environment where the subsurface conditions are difficult and existing improvements limit construction method and flexibility.


  • English

Media Info

  • Media Type: Web
  • Features: References;
  • Pagination: pp 585-593
  • Monograph Title: Grouting and Deep Mixing 2012

Subject/Index Terms

Filing Info

  • Accession Number: 01526787
  • Record Type: Publication
  • ISBN: 9780784412350
  • Files: TRIS, ASCE
  • Created Date: May 29 2014 10:15AM