Case Study 1: Woven vs. Non-Woven Geotextiles for Unpaved Roads

A logging company is building a temporary unpaved haul road over a soft, muddy subgrade ($CBR < 3$). The engineer must choose between a woven geotextile and a non-woven geotextile to place between the mud and the gravel base course.

Case Study 2: Selecting a Geomembrane for a Landfill Liner

A new municipal solid waste landfill requires a basal liner system to prevent toxic leachate from contaminating the underlying groundwater aquifer. The engineer must specify a geosynthetic for the primary containment barrier.

Case Study 3: Separation and Filtration in a French Drain

A homeowner is installing a trench drain (French drain) to intercept groundwater before it reaches their basement. The trench will be filled with clean, open-graded gravel and a perforated pipe. The contractor plans to wrap the gravel in a geosynthetic.

Case Study 4: Reinforcement using Geogrids in Embankments

A steep embankment is to be built over a localized zone of weak, compressible peat. The engineer is concerned about a deep-seated rotational shear failure of the embankment extending down into the peat layer.

Case Study 5: Survivability during Installation

A contractor is installing a woven geotextile as a separator beneath a railway ballast. During construction, heavy angular crushed rock is dumped directly onto the geotextile from a height of $2\text{ meters}$, and then compacted by heavy vibratory equipment. The geotextile tears in multiple places.

Case Study 6: Apparent Opening Size (AOS) and Permittivity

An engineer is designing a geotextile filter for a coastal revetment (seawall). The native soil behind the wall is a fine, uniform sand. The engineer selects a geotextile with a very small Apparent Opening Size (AOS) to ensure no sand escapes. However, during a severe storm, the seawall fails outward.