Research On Load Diagram Of Gravity Retaining Structures

Gravity retaining structure refers to a kind of retaining structure that balances the earth pressure behind the wall mainly on the gravity of the body of wall. It applies to the slope retaining project in the general area, flooding region and the seismic region. It has been widely used in railway engineering because of its simple structure, its easy materials-obtaining, and its easy construction.There are some assumptions adopted to make the design calculations of the gravity retaining structures, such as, coulomb active earth pressure theory used in calculating the earth pressure, conversion soil column theory used in calculating the train load, etc. For common railways, these assumptions can meet the security requirements. However, with the rapid development of high-speed railway, the speed of the train is significantly improved, and the dynamic load subjected by soil mass behind the retaining wall increases too. The safety and change of stress state of retaining structures began to receive more and more attention by the engineering organization. As a result, it is important and necessary to find out the rational loading diagram of the conversion soil column and the degree of influence by speed improvement on the stability of the retaining wall.A large number of domestic and foreign literature is searched and studied. Research is made on the loading diagram of conversion soil column of railway earth retaining structure in the standard of Germany and Japan, and the loading diagram in highway standard of China. Based on this, centrifuge model test and numerical calculation are carried out to analyze the influence on back earth pressure by the conversion soil column.Centrifuge model test is carried out aimed at two different wall types respectively: gravity shoulder wall and balance weight shoulder wall. Different loading distribution forms are simulated in the tests, including single-line distribution, single-line fully-loaded, two-lane distribution, two-lane fully-loaded. The influence on back earth pressure by the conversion soil column on different distances from the retaining wall is contrasted and analyzed.Based on the site condition of centrifuge model test, numerical analysis and calculation is carried out using the numerical analysis software FLAC3D. The influence on back earth pressure by the loading diagram of conversion soil column is analyzed; the back earth pressure and the wall stability coefficient generated by the dynamic load at different speed and different distribution forms are calculated, and the influence on the back earth pressure and the wall stability coefficient by the train speed improvement is summed up.In this paper, some interesting conclusions are drawn based on centrifuge test and numerical simulation studies of gravity retaining wall in the hope for providing some help in future analysis of gravity retaining wall.