Experiment on vertical earth pressure of high-fill culverts in Tumen-Hunchun expressway

To investigate the pattern of soil pressure on vertical direction of a culvert and the arching effect,earth pressure cells were buried on the top of the test culvert located in pile number RK365 + 510 in Tumen-Hunchun expressway to measure the vertical earth pressure under the fill soil heights of 4,6,8,10,12,14,16,18 and 20 m. The vertical earth pressure under different fill soil heights was analyzed. The calculation according to General Code for Design of Highway Bridges and Culverts( JTGD60-2004) was carried out. The errors between the calculated results and the measured results were analyzed. The results show that the vertical earth pressure on the culvert increases with the fill soil height,when the height is not more than 8 m; that the measured vertical earth pressure is larger than the calculated one due to the stress concentration effect of earth pressure cells; that the measured vertical earth pressure on the culvert table is larger than the one on the top of the culvert because of the arching effect above the culvert. Because the arching effect is unstable, the vertical earth pressure varies non-linearly. The transfer of soil arching effect was verified by the numerical difference between the measured vertical earth pressure on the culvert table and the one on the top of the culvert. The result calculated bysoil column methodin the code was larger than the measured result. Structure is not cost-efficient because the design is too safe. It was suggested that the fill soil on the top of culvert was assumed as load,the calculation expression of earth pressure under different soil heights was deduced according to the load distribution diffusion principle. A culvert can be divided into several sections with different size to improve its optimization potential.