Nomogram for the Installation Specification of Drain Pipes for Embankments

Groundwater levels in embankments often rise due to heavy rainfall, which can occasionally cause embankments to collapse. In order to decrease the ground water level, it is important to take countermeasures to drain the water from areas in embankments which could weaken in heavy rain. The drain pipe method for embankments has been adopted widely by Japanese railways as a water draining method. However, installation specifications for drain pipes have not yet been established, and the finer details of construction work currently depend on experience. This study therefore set out to evaluate the effect of drain pipes quantitatively, with a view to proposing a set of installation specifications for drain pipes in embankments, based on the evaluation and considering the height of the embankment, external permeance, inter alia.