Mechanical Characteristics Research Of Pipe Culverts Under High Embankments In Southern Mountain Areas By Centrifuge Modelling Tests

As the development of infrastructure construction in China, Culverts prevail in nowadays highway engineering. Pipe culverts, whose analysis and design theory are not precisely determined, are frequently used under high embankments in mountain areas. As a result, diseases occur continually because of the disparity between the mechanical analyses and practical condition. Hence, interactions among the pipe culvert, embankment fill, subgrade and, if required, foundation should be clarified to ensure actions applied on culvert are precisely determined, and that mechanical analyses can well describe practical conditions, and that the serviceability of the culvert is well kept, and that the design is with both practicability and cost-performance.The investigation of landform and geological condition along the Baotou-Maoming Highway Project shows that the soft soil are widely distributed and the valley landform is quite complex, which leads to the great increasing of embankment fill height. To cover these features, the fill heights of embankments, subgrade modulus, valley conditions and load shedding measurements under different work conditions are studied synthetically by using centrifugal test. Main results are following:(1) High embankment of the pipe culvert is defined as the fill height approaches 6.0m, for the equal settlement plane is usually formed 5.6~8.2m above the culverts and the minimum fill height at which the equal settlement occurs is 6m.(2) The compression of soil and stress occurred on the culvert may be overwhelmed as long as the fill height on the plane area is around 15~50m. EPS Plates are suggested to be assembled with the thickness of 50~75cm, 75~100cm, and 100~125cm respectively when the fill height are 15~20m, 20~40m and 40~50m.(3) Pipe culvert failure may occur under the 20m-fill-height embankments when the subgrade modulus excesses 15 MPa. An assemblage of EPS Plates with the thickness of 50~75cm is suggested to reduce the stress occurred on the culvert top.(4) An assemblage of EPS Plates with the thickness of 50~75cm is suggested when the fill height excesses 20 m and the valley width is more than 5 times of culvert diameter and the slope degree is over 45°.(5) Regression formula of Earth pressure and Earth pressure concentration applied on the Pipe culvert under multi-factor conditions.(6) Suggestions for design and construction on pipe culvert in southern mountain areas are given based on the research.The achievement of this research provides a theoretical basis for the design and construction of pipe culverts under high embankments, which is with great theoretical significance and engineering value.