Study On Earth Pressure On Retaining Walls On The Basis Of Soil Arching Effect

The determination of forces on structures which are connected to earth mass is of paramount importance in applied Geotcehnical Engineering. Classical earth pressure theories enunciated by Coulomb and Rankine have been widely used for the earth pressure analysis and the design of the retaining structures within the validity of the assumptions of these theories. Coulomb and Rankine,however,had some shortnesses:1.They assumed the lateral earth pressure distribution to be simply hydrostatic;2.In Coulomb's theory,the resultant earth pressures are obtained by the force equilibrium of sliding soil and the soil stress state is non-considered;3.In Rankin's theory,the earth pressures arc obtained by the stress. And, soil arching effect and the computation ofthe related earth pressure had been hot topics in geoteehnical engineering for many years, but there is only a little being done so far.In this dissertation, On the basis of the studies so far available, soil arching effect and earth pressure for retaining structure are studied in-depth. The main original work is as follows:1,Based on combining the idea and methods of two theories, the deficiency of the flat sliding surface in Rankine and Coulomb's theories and non-balance of the moment of sliding soil in Coulomb's theory is analyzed.2,The sliding angle of the passive and seismic states was analyzed by the idea of Zhang Ruiwen in analyzing active earth pressure on rigid retaining walls in the teanslation mode which was used to obtain the formula of slip level of inclination of the fracture surface through the static balance of the horizontal unit of soil.3,On the basis of the studies so far available, the deficiency of the lateral earth pressure coefficient is analyzed. The formulae of the lateral earth pressure coefficient is obtained.4,The value of the vertical stress in the lateral earth pressure coefficient of the solution process is the key. Most of predecessors assume that the level of unit soil surface vertical stress uniform or evenly distributed along the depth. The previous hypothesis was analyzed in this paper. The formula of lateral earth pressure coefficient was obtained by establishing reasonable vertical stress values.5,In the translational displacement mode, according to the equilibrium equation considering the static equilibrium conditions of horizontal unit of soil, the formulae of the passive earth pressure distribution, the resultant earth pressure, and the point of application of resultant earth pressure on retaining wall are respectively set up. And the calculating method obtained is verified rationale by comparing the computed result using this paper's method with the experiment results and the results obtained on the basis of Coulomb and Rankine theories. On this basis, the influence of internal friction angle and the angle of wall friction on the passive earth pressure distribution and passive earth pressure coefficient are subsequently discussed.6,In the translational displacement mode, On the basis of static theory of Mononobe-Okabe, Considering the soil arching effect, the static equilibrium and moment equilibrium equations are then derived from analysis on the stress of the layer of filling which is in a normal stress state using the method of horizontal layer analysis. After that, the formulas of active earth pressure, coefficient of earth pressure and application point of the resultant force which are more usable are respectively obtained. The influence of internal friction angle, wall friction angle, horizontal and vertical seismic coefficient on the angle of sliding surface, active earth pressure, coefficient of earth pressure and application point of the resultant force are numerically analyzed. Furthermore, the results of our method are compared with the results computed by methods in other references and experimental observation.7,Considering the state of turning around a point of the wall, based on the stress Mohr's circle of arching, according to the equilibrium equation considering the static equilibrium conditions of horizontal unit of soil, the formulae of the passive earth pressure distribution, the resultant earth pressure, and the point of application of resultant earth pressure on retaining wall are obtained.