EXPERIMENTAL AND THEORETICAL METHODOLOGY TO VALIDATE NEW GEOCOMPOSITESTRUCTURES FOR DRAINAGE

The non-homogeneous drainage structure, Somtube, incorporating mini-pe rforated pipes, cannot be designed by means of the usual rules. A spec ific theoretical approach had to be developed that took into account t he transmissivity of the drainage layer and the discharge capacity of the pipes. A computer program, which considers a non-linear relationsh ip between the discharge capacity and the hydraulic gradient, allows d etermination of each parameter when the others are known: length of th e pipes, distance between pipes, transmissivity of the drainage needle punched layer slope. and flow rate or water pressure in the needlepunc hed layer. Various hydraulic conditions are available: constant flow i n the soil with the pipes unsaturated, saturated or partially saturate d, or constant water head in the soil. An actual drainage test in a la rge-scale cell was performed, which validated the theoretical model.