Abstract: A trenchless method of installing a new poured-in-place manhole liner provides structural rehabilitation to an existing buried manhole, and is extended above the existing manhole to a higher pre-determined elevation to match the finished grade of a raised levee design. The new liner can be formed in a single or double stage process, which substantially eliminates trenching and excavation of soil, so that new levee soil is not disturbed. The process is faster and less expensive than building a totally new manhole, and maintains the structural integrity of the levee.

Abstract: The method of repairing a manhole begins with assembling concrete forms above ground to correspond to the shape of the manhole wall. Then, a plastic liner sheet is wrapped around the assembled forms and the seams are welded. The forming sections are then removed, and the liner is placed in the manhole. An annular space exists between the liner and the manhole wall. The forming sections are re-assembled inside the liner. Concrete is then poured into the annular space and allowed to cure. The forming sections are removed, leaving the liner anchored in a new monolithic concrete wall fully engaging the old manhole wall.

Abstract: The method of repairing a manhole begins with assembling concrete forms above ground to correspond to the shape of the manhole wall. Then, a plastic liner sheet is wrapped around the assembled forms and the seams are welded. The forming sections are then removed, and the liner is placed in the manhole. An annular space exists between the liner and the manhole wall. The forming sections are re-assembled inside the liner. Concrete is then poured into the annular space and allowed to cure. The forming sections are removed, leaving the liner anchored in a new monolithic concrete wall fully engaging the old manhole wall.

Abstract: A monolithic manhole is formed in a levee without trenching, to provide access to drain pipes within the levee for maintenance and repair of the pipes. The manhole is formed by first forcing an outer tube downwardly into the earth and levee and removing soil from within the outer tube to expose the pipe. An inner tube is lowered into the outer tube, with an annular space maintained between the tubes. The annular space is filled with concrete, which hardens to form a monolithic vertical wall. A concrete floor may be poured at the bottom of the wall and a cover attached to the top of the wall. A hole is cut in the pipe inside the wall to provide internal access to the pipe.