Abstract:

Aiming at the non-limit active earth pressure distribution of sand under the rotating about the base (RB) mode of rigid retaining wall around the bottom of the wall, the active failure process of sand is analyzed by discrete element numerical simulation. The results show that in the non-limit active state, when the friction angle of the soil at different depths becomes the limit value, the horizontal displacement required at this point is approximately the same, which is about 0.03%H. When the soil-wall friction angle reaches the limit value, the horizontal displacement required at this point is approximately linear with the depth z, that is S_δ =0.12%z; and there are many parallel "quasi sliding surfaces" in the soil behind the wall in the process of retaining wall moving. According to the simulation results, this paper modifies the calculation formula of friction angle mobilization value proposed by Liu, takes the thin layer parallel to the sliding surface in the soil wedge behind the wall as the oblique differential element by using the oblique differential element method, establishes the static equilibrium equation of the element in the non-limit active state, and obtains the calculation formula of non-limit active earth pressure against different displacements of the retaining wall under RB mode. Finally, the calculation results are compared with the simulation results and the measured data of model test, which verifies the rationality of the theoretical formula proposed in this paper.

Key words: non-limit active state, discrete element simulation, rotating about the base, sand, earth pressure, oblique differential element method, soil-wall friction angle