Lateral Loading Tests for Buried Pipe with Geosynthetics

The thrust force generated due to internal water pressure in a pipe tends to move the bend of underground pipeline to the backside. This thrust force is supported by the passive soil pressure at the back of the ground. The thrust force is commonly resisted by the concrete block at the bend. The earth pressure distribution at the back of the ground as the pipe moves laterally is not readily known. In addition, concrete block is not desired in the event of earthquakes because of its inertia force to move. In this paper, pit tests were conducted using a model pipe having a diameter of 90 mm in a dry sandy ground. Geosynthetic was used as anchor to resist the movement of the pipe. In addition, similar tests were conducted using a model pipe of square surface assuming it as a concrete block. The resisting force acting on the model pipe and the earth pressure in the sand ground were measured as the pipe moved horizontally in the ground. The development of slip surface in the backfill ground surface was also investigated. The test results showed that proposed lightweight method that used geosynthetic had significant effect in improving the resistance against thrust force.