关键词: 桩承式路堤, 高速铁路, 土拱效应, 动力响应, 数值分析

Abstract: The mechanism of soil arching effect is the key technical problem for load transfer of pile supported embankment. However, the soil arching in pile supported embankment under high-speed railway load is not well investigated. Based on the code for design of high-speed railway, a three-dimensional finite element analysis model of pile supported reinforced embankment under high-speed railway load is established, and its correctness is verified by the existing research results. According to the numerical model, the dynamic response of subgrade under the high-speed railway load is analyzed, including the variation of vertical displacement with time at different depths of roadbed and embankment load, as well as the distribution of velocity and acceleration along the depth. The results show that the vertical displacement of the roadbed and the embankment surface changes with time in an inverted M shape periodically, while the embankment bottom changes in a V shape periodically. It is also found that the velocity and acceleration decrease by 80% along the depth of subgrade. Then, the influence of different factors including pile spacing, embankment height and the properties of the embankment fill on the stresses and settlements are comprehensively analyzed. Hence, the soil arching effect in piled embankment under high-speed railway loading can be investigated. It shows that the soil arching effect remains valid but weakened under the dynamic loading, which weakens the maximum under the peak load, while restores under the valley load. Also it is found that the influences of pile spacing and embankment height are obvious on soil arching effect under dynamic loading, while the effects of friction angle and dilatancy angle of embankment fill are relatively small.

Key words: piled embankment, high speed railway, soil arching effect, dynamic response, numerical simulation