The Research On Several Problems Of The Earth Pressure Alculation Theory

It is well known that Coulomb’s theory of earth pressure and Rankine’s theory ofearth pressure are still widely used in engineering construction because they aresimple and easy to be mastered. Although the two classical theories are based on theirrespective assumptions with very strict conditions, many special cases will appear inpractical engineering. Directly adopting the classical theories will often lead toerroneous results. Basing on the two theories and considering their existing defects,many scholars put forward some new solutions, but up to now those solutions stillneed be further gone in.This paper carried out some pointed discussions respectively for some existingearth pressure theories, and put forward some new ideas so as to make the mechanicalmechanism between soil and retaining structures more clear and the calculation forthe earth pressure more simple and accurate.The following are the research for someproblems:（1）Proceeding from the limit equilibrium theory，as a solution to the problemof limit soil mass and its corresponding sliding surface behind the wall underRankine’s active theory, this paper pointed out the reasonable form of the slidingplane, and argued for the answer of corresponding sliding surface of limit soil massunder Rankine’s active earth pressure. Appropriate interpretation was given as well tothe problem of tensile stress behind the wall under Rankine’ theory. On basis,according to the relationship between tensile strength and shear strength of soil, thispaper derived the formulas of active earth pressure by considering the tensile stress ofthe soil.The conclusion of this paper is a supplement and improvement to Rankine’searth pressure theory.（2）In practical engineering, the surface of filled soil behind the retaining wallis often uneven, and the active earth pressure on the wall can not be calculateddirectly by the classical earth pressure theory.Aware of practical engineering, thispaper studied the earth pressure for retaining structure for the different fillingsurfaces.（3）The stress state of the soil behind the retaining wall was analyzed:Considering the problems in Coulomb’s theory, such as the imbalance phenomenon ofstatic torque of the limiting equilibrium soil mass behind the wall and no matching ofsliding plane and the stress state, improved method was put forward. In addition, this paper also studied the soil arching effect of soil mass behind the retaining wall, thearch crown of a minor principal stress arch and some problems of soil arch effectprinciple. Calculation method was proposed for lateral pressure coefficient.（4）Simulation analysis and numerical verification were carried out by using ofa finite element software, relating to the research in this paper.