Research On Earth Pressure Acting On Retaining Wall From Limited Backfills Subgrade

In the construction of road, it is inevitable to build half-filled and half-dugembankment because of restrictions of complicated topographic conditions. In orderto ensure the stability of half-filled and half-dug embankment, embankment retainingwall should be constructed. Calculation of earth pressure is the key issue in retainingwall design, which affects the safety of the retaining wall design. Half-filled andhalf-dug embankment belongs to limited backfills, so the earth pressure acting onretaining wall is limited backfills pressure. At present retaining wall design is mainlybased on the calculation of active earth pressure. To reach the state of active earthpressure needs sufficient displacement, while in actual projects some retaining wallswill not have enough displacement. For the calculation of active earth pressure fromfinite backfills, only resultant force can be obtained by the method of specification,while the distribution law of pressure cannot be known. In the theory of Coulombearth pressure, earth pressure distribution is assumed to be linear. However, someexperimental results show that the distribution of earth pressure is nonlinear. Thisarticle mainly includes the followings:1. Based on the concept of mobilized angle of internal friction, the static earthpressure acting on retaining wall from semi-infinite backfills embankment isestablished after the analysis of Mohr’s cycle, and the static earth pressure fromlimited backfills embankment is also established after taking the effect of retainingwalls back and rock excavation face into consideration, meanwhile comparison withactive earth pressure calculation method in specification has been done. Calculationformula of static earth pressure coefficient is established in different conditions.2. Based on the assumption of movement associated flow rule, for the movementmode of translation, formula of active earth pressure on retaining wall fromsemi-infinite two-layered backfills is established by using the method of level-layeranalysis. For two-layered and limited backfills embankment, taking the effects ofbedrock excavation faces into consideration, calculation analysis of active earth pressure acting on retaining wall is done in different cases.3. This paper presents a numerical study on the behavior of active earthpressures and earth pressures at rest behind a rigid retaining wall with limitedbackfills embankment based on ANSYS, and analyze the size and distribution ofearth pressure acting on retaining wall. Effect on earth pressure of friction coefficientbetween contact surface and backfills, internal friction angle of backfills andinclination of excavation face is analyzed.