Influence Of EPS Slab On Earth Pressure And Deformation Characteristics Of High Fill Subgrade Arch Culvert In Valley Terrain

The load distribution and fill settlement deformation of highway high fill culvert are complex.It is difficult to accurately calculate the earth pressure distribution and fill settlement deformation by using the current design calculation method,which leads to significant difference between the actual working state of high fill culvert and the design expectation,and threatens the stability of culvert body and the safety of highway operation.Based on the high fill culvert project of Baotou Maoming Expressway(Guangdong section),this paper establishes a three-dimensional spatial model of arch culvert foundation EPS slab,and studies the earth pressure distribution and fill settlement deformation characteristics of high fill arch culvert under different gully shapes and different EPS slab layout parameters by means of geotechnical centrifugal model test and numerical simulation(1)The results show that the earth pressure of high fill arch culvert in valley terrain is less than that in flat terrain,and the settlement of fill in flat terrain is in a negative trend The results show that the earth pressure of high fill arch culvert has a negative correlation with the width of the gully and a positive correlation with the slope of the gully;the most significant gully shape affecting the earth pressure of high fill arch culvert is that the width of the gully is between2 ～ 5 times of the span of the arch culvert and the slope of the gully is between 75 ° and 90 °.(2)EPS board has a significant effect on the earth pressure and fill settlement at the top of high fill arch culvert.After laying EPS board,the earth pressure at the top of culvert changes from "normal distribution" to "W" distribution before laying,and the soil settlement at the top of culvert changes from "W" distribution to "V" distribution.The earth pressure of arch culvert is approximately linearly related to the thickness and width of EPS board.(3)It is proposed that the vertical earth pressure concentration factor KS on the top of arch culvert under different valley terrain and different EPS slab laying conditions is used as an index to evaluate the impact of valley terrain on arch culvert,which supplements and improves the earth pressure coefficient KS on the top of arch culvert in code for design of highway high filled culverts.(4)The load reduction technology of high fill arch culvert is put forward: the original valley topography should be retained as much as possible in the construction,and reverse excavation can be adopted under the conditions of economic and technical feasibility;the laying width of EPS slab should be more than 4 times of the clear span of arch culvert,and the laying thickness should be more than 50 cm.