Cutoff Wall Connections to Existing Large Diameter Pipes-PPT Presentation

PPT Presentation

Pdf Summary

The presentation describes connections between a new cutoff wall and three existing large-diameter pipes as part of the Herbert Hoover Dike Rehabilitation project in Florida, commissioned by the USACE. The broader project included 17.6 miles of cutoff wall installed using cutter soil mixing. At one crossing, the wall had to connect to two 48-inch steel pipes and one 96-inch corrugated metal pipe (CMP).<br /><br />The CMP’s deteriorated condition, including a leaking joint, made jet grouting directly against it unsuitable. The team instead excavated around the pipe, partially removed it, and installed a jet-grouted cutoff wall beneath the pipes. The CMP was then restored, and the excavation was backfilled with controlled low-strength material (CLSM) to connect the jet-grouted section to the cutter soil-mixed wall.<br /><br />Construction involved a temporary retaining system, dewatering and bypass pumping, excavation and partial pipe removal, and asbestos abatement after asbestos was found in the CMP coating. A work platform was established inside the excavation to install the jet-grouted wall. The team then formed a key-in trench, installed concrete collar connections and HDPE reservation pipes, backfilled with CLSM, and completed the connection to the main cutoff wall.<br /><br />The work was required to meet criteria for continuity and homogeneity, an 18-inch thickness, specified unconfined compressive strength, permeability, and depth. The presentation concludes that combining construction methods produced quality connections, while effectively managing safety and quality risks. The work was completed on time and within budget, to the client’s satisfaction.

Keywords

Herbert Hoover Dike

cutoff wall

USACE

jet grouting

cutter soil mixing

corrugated metal pipe

controlled low-strength material

asbestos abatement

dewatering

pipe connection