Research On The Vertical Earth Pressure Theory Beneath The Layered Buried High-Stacked Embankment

With Chinese western development, there are more and more above 20m high embankments and corresponding culverts. However, because lack of the reasonable vertical earth pressure theory for designing culverts, some of them fail in the period of construction or after completion of work for using smaller size of structure, in some case culverts under high embankments are designed to bear uncertain pressures with over big size and lead to more cost. So the issue of how to design the culvert economically and safely is concerned more and more.Based on the culvert under Jinyu high embankment of Chongqing priority project, the vertical earth pressure distribution and change characteristic are studied in the paper through on-the-spot arrangement of the test components, calculations of different theories, numeric simulation and so on. The research results have instructive to the design and construction of the culvert under high embankment. On the basis of these, the paper put forward the effective method of reducing the vertical earth pressure on the culvert.The fruits and the work of research in the thesis as follow:(1) The variable principle of vertical earth pressures on the culvert beneath high embankment are investigated in the thesis. The results of the test and the numeric simulation show that the vertical earth pressures are obviously lower than theoretical value byσ=γH , the pressures on the top of culvert increase nonlinearly with the variation of height of embankment.(2) The nonlinear theories of vertical earth pressure calculation on the culvert beneath high embankment are investigated in the thesis. The results of regression analyses and Compared the nonlinear theory with other theory of vertical earth pressures indicate the pressures of nonlinear formula withσ=ξγHm are very close to the test, the pressures for designing culvert are more economic and safe, it is the reasonable method for vertical earth pressure calculation at present.(3) The arching action above the culvert under high embankment is investigated in the thesis. The results of test and numeric simulation indicate that the soil arching are formed above the culverts under high embankment, instability is the characteristic of the soil arching, and a part of pressure is still transferred to the top of culvert when the height of fill is increase.