| Retaining wall is a kind of supporting structure commonly used in civil construction, water conservancy and hydropower, traffic engineering, which can be reinforced or ward off the adverse geological body, deformation and failure to effectively control the wall before, after the structure. How to accurately calculate the earth pressure distribution, resultant force and its application point on retaining wall is the key to play its role, which involves a basic subject of the soil mechanics and geotechnical engineering field; the calculation method of Classical Rankine’s and Coulomb’s earth pressure theory and limit equilibrium theory based on the development of the because of its mechanical principle is clear, simple calculation, still as a theoretical basis for engineering design of support structures. However, a large number of engineering practice and research show that:the classical earth pressure theory is not only applicable scope is relatively limited, the calculation results will not fully reflect the actual stress state of retaining walls, and the theory itself has many disputes.In the scope of application, Rankine theory is only applicable to the wall back is vertical and smooth, the backfill surface level; while the Coulomb theory requires filling as the ideal bulk, which is only suitable for non cohesive soil. But in practical engineering is not smooth wall back upright, the backfill are cohesive soil, when the wall and cohesive soil relative displacement, wall back fill and not only effect between friction, there is also some adhesive force, this phenomenon has some engineering pile test confirmed.In the theoretical result, the classical earth pressure theory that earth pressure is linear distribution, action point of resultant force and distance is1/3times of the wall height of the wall. But the engineering test, model test and numerical analysis results show that:the ultimate limit state, Rankine and Coulomb active earth pressure force error is relatively small, but the distribution of earth pressure is nonlinear, the resultant point higher than1/3times of the wall height, and analysis of the classical earth pressure theory results only in specific situations can be established.Deficiencies in the theory itself,(1) the Coulomb theory ignores the distribution of earth counterforce, only consider the balance stress of horizontal and vertical sliding wedge, and not considering moment equilibrium of sliding wedge, but it’s the action point of resultant earth pressure position of analytical solution of the force condition;(2) Rankine theory ignores the wall back and fill between friction shear stress, but by the friction shear stress caused by soil arching effects on the earth pressure distribution and its application point;(3) the classical earth pressure theory for translation mode retaining wall paper, but in engineering practice, retaining wall under various conditions constraints, wall may occur in different deformation mode, the soil shear strength of play along the wall to the uneven distribution;(4) classical earth pressure theory is only suitable for calculating the ultimate state, but by supporting object constraints, can make the filling behind the wall to wall displacement limit equilibrium state does not usually occur, earth pressure of active earth pressure and passive earth pressure between, namely non-limit state earth pressure. So the wall movement modes, motion displacement, arching effects etc. All of these factors will have an important impact on the earth pressure.In this paper based on the previous studies, the anti-stress distribution and action point of resultant force for Coulomb theory, generalized Coulomb earth pressure, cohesive or non-cohesive backfill conditions considering wall deformation mode and displacement effect of non-limit state earth pressure and other aspects of the theory of computation for further study, combined with field and laboratory the existing research results were compared to verify the proposed theory. |
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