FRENCH DRAINS: Groundwater traveling under your foundation can lead to a number of long-term issues. If you’re experiencing basement flooding, foundation damage, or rainwater drainage issues, then drainage correction may be the best solution for your home. One commonly used form of drainage correction is the French drains.
French Drain: Drainage is the collecting and transporting of precipitation, groundwater and/or other fluids.
Over the past 30 years or so, geotextile filters have increasingly replaced the aggregate filters to improve the natural drainage capacity of low-permeability soils.
It is also important that drainage systems maintain adequate drainage capacity for long-term performance even when they are subjected to high earth pressures. To avoid clogging and contamination of the drainage layer a filter must always be incorporated in a drainage system.
Typically, geosynthetic drainage composites consist of a core sandwiched between
geotextile filters. (Fig.8).
Such filters must possess good long-term filtration properties. An excellent strength with a high durability and good resistance to installation stresses.
The malfunction or premature failure of a drainage system can create serious safety and functional problems for the earth structure concerned. At the very least, a drainage failure will necessitate costly remediation and attendant disruption. It is vital
that a filter material is used that can function effectively over the long term even with the most critical soils.
Sourse: Technical Handbook