Drainage Systems – Repair of Leaking Joints & Compaction of Weak Soils

Problem:

Leaking joints in drainage box culverts or pipes allow foundation soils to be removed from the pavement system. The soils are carried out with the water that moves through the pavement system and out though the leaking joints. This causes loss of support for the pavement system – causing settlement and premature cracking of the pavement.

This can also cause voids around the culvert or within the pavement system that can lead to sudden movement in the pavement and at times catastrophic failures. Some drainage system joints are intact but simply have poor compaction over the culvert or pipe that need stabilization.

Solution:

Apply the URETEK Deep Injection Process with URETEK 486 water resistant expansive polymer into the foundation soils beneath the pavement system at various elevations to compact loose soils to properly support the roadway. Continue injection into the soils as needed to raise the pavement to grade. Inject the polymer around leaking joints to fill voids and compact the soils around the drainage system and to allow material to enter the leaking joints while expanding to provide a positive encasement seal of the joint.

Expected Results:

  • Compact the loose soils around and above the drainage system to provide sufficient support for the roadway.
  • Seal any leaking joints in the culverts or pipes to prevent foundation soils from leaving the area via the drainage system.
  • Continued injection into the soils can lift the pavement system if needed.

Benefits:

  • Zero daytime lane closures.
  • Complete reconstruction of the drainage system is not required.
  • Tear out and replacement of the pavement and support soils to excavate to the drainage system is not required.
  • Tremendous dollar savings over replacement.
  • Injection to seal the leaking joints in the drainage system can be easily controlled to prevent filling of the pipe and waste of material.
  • Yearly re-sealing of the drainage system joints from the inside is not required as is often the case with traditional methods.
  • Injection can be accomplished in wet soil conditions as the URETEK 486 STAR hydro-insensitive polymer will form a dimensionally stabile polymer even when injecting into saturated soils. The expansion process will also drive the water out of the soil system.

Alternates:

  • Removal and replacement of pavement, weak foundations soils and culvert or drainage pipe is extremely expensive and causes significant traffic delays.
  • Spot repair of the leaking joint requires expensive and time consuming removal of the pavement and foundation soils in order to reach the drainage system to make the repair. Following spot repair and testing, the foundation soils must be installed and compacted and new pavement placed. Compaction of the soils is difficult and often results in pavement settlement in near future.
  • Traditional patching of the pipe joint from inside can prematurely fail as it is not a positive seal – water will continue to try to enter the joint from the voids around the pipe. Since this alternate does not address the voids around the pipe, the pipe can easily flex and break the new seal at the joint. Additionally the voids around the pipe can continue to allow water flow along the pipe during a rain event keeping the possibility open for catastrophic failure. These voids also allow for the pavement foundations soils to settle into the voids around the pipe, causing premature cracking and settlement of the pavement.

Reference Documents:

  1. Classic Culvert Failure – This four minute video demonstrates what can happen when the soils around culverts are not compacted against the culvert – the opening is available for a catastrophic failure.

  2. Damage Control