Modelling of groundwater infiltration into sewer systems

摘要

Groundwater infiltration into urban sewers represents a problem that influences costs and management of technical systems. The hydrodynamic groundwater software MODFLOW is used to analyse the influencing variables of the infiltration processes. Besides the hydraulic conductivity of the soil and the piezometric head in the vicinity of the sewer pipe, properties of the sewer trench, the shape and the size of leaks are important influencing factors. A nonlinear-regression method is applied to develop a one-dimensional approach in accordance with the MODFLOW results and Darcy's law. Monte Carlo simulations and the developed one-dimensional model are used to assess the leak area and the range of pressure loss in the vicinity of the pipe leaks. By additional sensitivity analysis it was found that the infiltration factor and the conductivity of the backfill are very important for the calculation of the leak area.