Abstract
To prevent clogging in geotextiles, various types of nonwovens were compounded by thermal bonding method. In these geotextile composites, the function of the upper layer of small pore sizes is to minimize loss of soil particles while that of the bottom layer of large pore sizes is to transmit the soil particles passing through the upper layer. Transmissivity which has been used as an index in evaluating the drainage capability was measured according to ASTM D4716. The variable considered in the experiments was the compressive stress applied on the geocomposite. It gave a significant effect on thickness, permeability, and transmissivity. When compressive stress of below 1 kgf/$\textrm{cm}^2$ was applied, the increase of stress produced a significant decrease of transmissivity. However, when stress of over 1 kgf/$\textrm{cm}^2$ was applied, the increase of stress, even though it was sufficiently large, did not produce much change in transmissivity. From these results, an empirical logarithmic model was derived to predict transmissivity as a function of stress.
