Penn Forest Dam, Bethlehem, PA
Dam Replacement Project – Grout Curtain
The Penn Forest Dam is one of the largest RCC dams in the United States. As part
of the construction for the RCC replacement dam, foundation grouting was the specified
treatment to mitigate water seepage in the rock foundation below the new RCC dam. The
2,400 foot long grout curtain was specified as 3 rows constructed with split spaced
holes 200 feet deep. ACT was the Prequalified Specialty Grouting Subcontractor
responsible for installation of the specified grout curtain.
Work completed by ACT included: overburden and rock drilling, extensive water testing,
diamond core drilling of grout holes, diamond core drilling of 300 foot deep near horizontal
drainage relief holes in the gallery of the dam, and pressure grouting of 135,000 lineal
feet of grout holes. A computer monitoring program was used to display, record and direct
the grouting program. All work associated with the grout curtain installation was performed
concurrent with the construction of the new RCC replacement dam without experiencing any
delays in schedule.