Municipal Township Leaking Outfall Pipe

Challenge:

Voids were present under bridge installation and beneath outlet pipe. Since the stability of the soil underneath the creek bed had been compromised, the flow of water was diverted from its natural course and added to the breakdown of existing voids. The instability in the soil also resulted in depressions in blacktop above concrete bridge.

Solution:

The injection plan was implemented by drilling ¾” holes and placing 5/8” tubing in strategic locations along and under the concrete structure.  Voids were filled on the sides of the outlet pipe. The polymer was injected into the ground to densify the soil.  The polymer itself, under compression, has a density greater than the original compacted soil.  Containing the material this way will help rigidity and act as a support system for the concrete wall. This process allowed the voids to be filled at the bottom of the concrete wall as well as around the outlet pipe. By injecting on both sides of the pipe system we were able to build a structure of polymer and soil to re-support the pipe and prevent further settlement.

Results:

The roadway was re-supported and returned to service immediately after completion of project.  Voids were filled, and water flow had been redirected to its natural course.  No excavation was necessary.