Field Consolidation of High Ash Papermill Sludge

Settlement and pore pressure measurements on a carefully constructed high ash papermill sludge landfill are presented. The landfill consisted of two sludge layers, each initially 10 ft thick, with sand drainage blankets at the top, between the layers, and at the bottom. An earth dike provided lateral confinement of the soft sludge and 3 ft earth surcharge was placed on the upper sand blanket. A detailed description of the field behavior is given along with analyses based on laboratory results and soil mechanics theory. The ultimate settlement, time rate of settlement, and pore pressure dissipation are analyzed for each layer. Two consolidation theories which include secondary compression in their mathematical formulation are included in the analyses, along with Terzaghi's theory. Pore pressure generated during construction and those existing at the completion of primary compression (residual) are analyzed.