Abstract：With the development of underground engineering in cities，people pay more attention to the calculation of earth pressure for limited soils in foundation supporting projects. However，Rankine¢s and Conclom¢s theories based on semi-infinite space assumption are not suitable for calculating the earth pressure of limited soils. Based on the limit equilibrium theory and the hypothesis of planar sliding plane，a formula for calculating the angle of shear failure in limited soils is deduced with the consideration of cohesion force and the width of limited soils. And then，a formula is proposed to calculate the active earth pressure of limited soils exerted against the supporting system. The formula shows that the angle of shear failure of limited soils is no longer the one in Conclom¢s theory. And the angle of shear failure is no long equal to 45°+j/2，but is a variable related to the width of limited soils，the cohesion of soil，the friction angle of soil and the depth. It is found that the angle of shear failure of limited soils increases nonlinearly with the increase of the depth，and decreases with the increase of the width of limited soils and the cohesion of soil. It is interesting that the angle of shear failure in limited soils decreases firstly with the increase of friction angle of soil，but latterly it will increase with the increase of friction angel of soil when it reaches to a certain degree. Finally the calculated results using the deduced formulas for the angle of shear failure and the active earth pressure of limited soils are analyzed by comparison with those of Rankine¢s theory. It proves the present formulas are reasonable.
