SRK Reno has designed a “boot” configuration that can be used for pipeline penetrations through a synthetic HDPE geomembrane pond liner; it has been approved via regulatory permitting processes for construction. The boot design, illustrated in the figure below, provides a drainage connection to the low point in a secondary liner to collect and dissipate fluids leaking through the primary liner, thus eliminating the potential for head development and leakage from the secondary liner.
The Leakage Collection and Recovery System (LCRS) system design incorporates a pre-manufactured 6 x 2 inch dual containment elbow. The elbow is factory-welded to a 12 inch diameter blind flange; as is a 4 x 4 foot 80 mil HDPE apron. The apron allows for field overlapping and wedge-welding with the surrounding secondary (lower) liner and minimises field extrusion welds. The elbow is set in a cast-in-place concrete foundation.
The top surface of the concrete is sloped to the center drain at approximately 4H:1V, to form a firm foundation for field welding that minimises stresses on the liner-elbow connection during construction and subsequent loading. It also provides a means for clean-water testing the system for leaks before operational commissioning. The sloped surface also facilitates overlapping of the secondary liner seam in the flow direction to minimise potential hydrostatic head formation over field seams.
