Study On Calculation Of Earth Pressure Behind Retaining Wall Under Static And Dynamic Loads And Its Related Issues

The studies on the calculation of seismic earth pressure under static and dynamic loads and the sliding surface of the rigid retaining wall under limit state are presented. The calculation method of earth pressure with multi-layered and the stability of the retaining wall under seismic loads are investigated, and corresponding calculative formulas are deduced.The principal contents and original work are as follows:1. Based on the sliding plane hypothesis, a formula is derived for the calculation of earth pressue with the consideration of the cohesion force on sliding plane and the adhesive force on interface of soil backfill and retaining wall. The formula can be degenerated to Coulomb’s and Rankine’s earth pressure expressions. Results show that the Coulomb’s and Rankine’s earth pressure expressions are the special case of the present solution. The earth pressure of complex condition can be calculated using the current formula.2. A resonable formula is derived for the calculation of seismic active earth pressure on retaining wall with multi-layered cohesive soil backfill. The formula can be degenerated to the calculation formula of homogeneous backfill. The calculation results of present study are compared with those of improved layer method and measured values, and the results accorded well with the measuring results. The active earth pressure acting on retaining wall with granular soil can be calculated by the method of layer analysis, whereas, it is suggested to adopt the method proposed in this chapter to calculate the active force with cohesive soil backfill.3. Based on the differential element method and variational principle, the sliding surface of the rigid retaining wall under active and passive conditions is studied, and the analyitc solution to the sliding surface curve is derived. The effects on the active earth pressure of the retaining wall and various parameters of the soil backfill with curved sliding surface are analyzed, revealing the the cohesion and internal friction angle of the backfill are the key factors determining the value of active force.4. A modified pseudo-dynamic approach is proposed to overcome some shortage in method of seismic earth pressure calculation. The formulas are derived for the calculation of lateral earth pressure and total earth pressure under seismic condition by using pseudo-dynamic method. The effects of various parameters of retaining wall and backfill on the seismic earth pressure are explored. The formulas for the computation of safety factor against sliding and overturning are also presented by pseudo-dynamic analysis.5. In view of the shortages of the existing sensor in testing rigid load and semi-rigid load, a new strain beam sensor is developed. The component structure and working principle of the new sensor is introduced, and the advantages of this new earth pressure sensor are summarized. The feasibility and reliability of the earth pressure sensor are examined by laboratory experiments.The calculation theory for earth pressure of retaining wall presented in this paper is an useful supplement to existing theory. The new approach and new results presented in this paper can be used in stability and earthquake-resistance design of retaining wall.