Stabilizing Leaking Sand Behind MSE Walls

The Kansas Department of Transportation (KDOT) has a large number of mechanically stabilized earth (MSE) panel walls with sand backfill. Some of these walls have experienced problems with sand flowing out between the panel joints because the geotextile filter fabric is not present over the joints. Untreated loss of backfill can result in conditions that become progressively worse. According to the Texas Department of Transportaiton (TxDOT), once loss of backfill begins, it gets worse as the surface area of internal voids increases. If the process is allowed to continue and voids get large enough, the wall may begin to experience panel movements and distress. For this reason, evaluation of the wall and repairs should be timely. Possible solutions to this problem include reducing water flow through the backfill, blocking the backfill from being able to flow between the panels, adding a cementitious agent to the backfill to stabilize it, or some combination of these. Sealing surface joints above the wall to reduce water flow will always be helpful but may not be sufficient. One blocking solution promoted by TxDOT is using backer rod and a sealant to fill the joints. Some TxDOT districts have used expandable foam as a blocking agent, although KDOT tried this and had a poor experience. A more preferred outcome would be one where the sand itself is stabilized, the surface of the wall remains uniform (irregular seams with backer rod are not present/visible), and there is at least some drainage permitted. These objectives could potentially be achieved using a thin polymer, cementitious, or biological grouting agent to cement the sand together in the volume of sand immediately around the joint. The grout would be injected into the sand using a wand inserted through the gap between panels. This cemented volume could still have some permeability to permit some seepage and would not be noticeably different from the rest of the wall joints in appearance. If injection with a wand proves feasible, this would likely be a more cost-effective alternative than backer rod and silicone sealant due to lower labor and material costs. Voids in the backfill would be addressed with a different material, such as urethane foam, a more viscous grout, lightweight cellular concrete, or other material.

    Language

    • English

    Project

    • Status: Active
    • Funding: $77,481.00
    • Contract Numbers:

      K-TRAN: KU-25-1

      RE-0898-01

      C2241

    • Sponsor Organizations:

      Kansas Department of Transportation

      Eisenhower State Office Building
      700 SW Harrison Street
      Topeka, KS  United States  66603-3754
    • Performing Organizations:

      University of Kansas Center for Research, Incorporated

      2291 Irving Hill Drive, Campus West
      Lawrence, KS  United States  66045
    • Principal Investigators:

      Parsons, Robert

      Han, Jie

    • Start Date: 20240701
    • Expected Completion Date: 20260630
    • Actual Completion Date: 0

    Subject/Index Terms

    Filing Info

    • Accession Number: 01942497
    • Record Type: Research project
    • Source Agency: Kansas Department of Transportation
    • Contract Numbers: K-TRAN: KU-25-1, RE-0898-01, C2241
    • Files: RIP, STATEDOT
    • Created Date: Jan 13 2025 2:59PM