ABSTRACT
This paper describes a Laboratory model tests to measure the cumulative (or permanent) settlement of soil surface (SSS) and cumulative (or permanent) vertical diametral strain (VDS) of plastic pipe (polyethylene pipe) under repeated loads of low frequency (up to 0.5 Hz). These tests were carried out, with a physical model which was developed in Khajeh Nasir Toosi University of Technology.
The parameters varied in the testing program include height of buried depth, relative density of sand and intensity of stress on the soil surface. The records of the VDS and SSS due to the repeated loads have been compared in different conditions. Based on the model test results, a critical buried depth and relative density of soil were observed which can be reduce the VDS and SSS and increase the safety of buried pipes under various intensity of repeated loads. There are also many other results, the descriptions and discussion about which are given in next sections.
