The current design practice in the UK for estimating the soil pressure on a buried pipe under traffic loads is based on a simple equation derived using a Boussinesq solution. In order to test and verify this equation, and study the effect of pipe diameter and backfill height for rigid (concrete) and flexible (polyvinyl chloride (PVC)) pipes, a study has been conducted using three-dimensional finite-element modelling. It was found that increasing the diameter of the concrete pipe non-linearly decreases the maximum vertical displacement, while the relationship between the concrete pipe diameter and the maximum thrust force was found to be dependent on the backfill height. Increasing the diameter of the PVC pipe linearly increases the displacement and the maximum thrust force. The effect of traffic live load on the maximum thrust force becomes insignificant for a cover depth larger than 2 m and 3 m for the concrete and PVC pipes, respectively. The results indicate that there are significant issues with the m...

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The response of buried pipes to UK standard traffic loading

Seismic performance of small earth dams with sloping core zones and geosynthetic clay liners using full-scale shaking table tests

Diameters and wall thicknesses of flexible pipes are usually designed as per hydraulic requirements, such as flow capacity, internal fluid pressure, and pipe material properties. Proper emb...

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Development Of A Model For Estimation Of Buried Large Diameter Thin-walled Steel Pipe Deflection Due To External Loads

Large-diameter buried steel pipes (BSPs) have been widely utilized in water diversion and hydropower fields. This paper presents a comprehensive numerical investigation on the interaction between the large-diameter pipe and soil under three typical working conditions, to capture the structural mechanical behaviors of pipe deformation, soil displacement, and soil pressure. Furthermore, a parametric analysis of pipe diameter is conducted, along with the sensitivity study of soil parameters based on the orthogonal test method. The results show that the water weight increases the pipe deformation significantly by 14%, while the high internal water pressure decreases the deformation greatly with the maximum effect of 39%. The pattern of soil pressure at the top of the pipe changes from parabola to double-hump as the pipe diameter varies from 0.5 m to 5.0 m. The pipe deformation and soil pressure keep increasing with the pipe diameter, but the safety margin for prism load decreases gradually. Pipe deformation and soil pressure are very sensitive to the elastic modulus and Poisson’s ratio of backfill. Friction coefficients of soil-soil (trench sidewall) and pipe-soil have great influences on the soil pressure, while the bedding material and backfill cohesion have small effects on it.

Pipe-Soil Interaction and Sensitivity Study of Large-Diameter Buried Steel Pipes

Full scale investigation of GCL damage mechanisms in small earth dam retrofit applications under earthquake loading

https://www.jstage.jst.go.jp/article/jcigsjournal/31/0/31_167/_pdf

Full-scale shaking table tests for small earth dams with sloping core zone and geosynthetic clay liner

Field buried pipe tests were conducted using steel pipes with 3500mm-diameter and 26mm-thickness as a part of Irrigation Pipeline Project. In current design for irrigation pipeline in Japan, there are no design criteria for pipeline with diameter larger than 3000 mm. In the field tests, two cases of backfilling methods were employed. In Case 1, soil-cement was used as backfill material to a height of half the diameter measured from the bottom of the pipe. In Case 2, soil-cement was used as backfill to a height of quarter diameter measured from the bottom of the pipe. The mixed rock, which was recycled crushed concrete and crushed gravel, was backfilled above soil-cement to the top of the pipe. The pipe was buried under a depth of approximately 3.0 m in both cases. Displacement transducers were installed in the pipes and strain gauges were attached to the inner of the pipe. Earth pressure transducers and pore water pressure transducers were installed in the backfill materials around the pipes. The deformations in each of the backfilling stage were measured. It is found that the behavior of the buried pipe was strongly influenced by backfilling methods and external force.

Field Test for Buried Large Steel Pipes with Thin Wall

https://www.jstage.jst.go.jp/article/jcigsjournal/31/0/31_175/_pdf

Influence of geosynthetic clay liner laid in a staircase shape in embankment on seismic behavior of small earth dam

This paper presents an overview of field tests for buried pipe, which were conducted using steel pipes with 3500 mm diameter and 26 mm thickness. In this full-scale test, five kinds of construction site were employed. The depth of soil cover was approximately 3.0 m in every case. Sheet pile method was employed in Case-5, and open-cut method was conducted in the other cases. Displacement transducers were installed in the pipe and strain gauges were circumferentially attached to the inner of the pipe. The deformation of pipe was observed for over a year by those measures. Therefore, it is found that the behavior of the buried pipe was strongly influenced by backfilling methods. In addition, FEM analyses were conducted to confirm the behavior of soil-pipe interaction. Thus, it is found that the inhomogeneous strength of backfill materials brings local deformation of the pipe.

Tetsuya Oda

Papers

Seismic performance of small earth dams with sloping core zones and geosynthetic clay liners using full-scale shaking table tests

Full-scale shaking table tests for small earth dams with sloping core zone and geosynthetic clay liner

Field Test for Buried Large Steel Pipes with Thin Wall

Influence of geosynthetic clay liner laid in a staircase shape in embankment on seismic behavior of small earth dam

Field Measurement and Numerical Analysis for Buried Large Diameter Steel Pipes