INVESTIGATION ON FILLING HEIGHT OF EMBANKMENT ON UNSATURATED SOFT GROUND WITH STIFF CRUST

The stiff crust commonly distributed in the soft ground area has a good capacity for load transmission in embankment engineering, and its beneficial effect should be brought into a full play.Analytical formulae for both the critical edge load and critical load of unsaturated soft ground are deduced with taking into account of the stress dispersion and self-weight berm of stiff crust.It is assumed that the strength of unsaturated soils is governed by the unified shear strength formulation and a hyperbolic model of suction angle.Then, analytical solutions of the critical edge filling height and critical filling height of embankment are presented, whose applicable conditions and implementation steps are also proposed.Finally, the influences of various parameters involved are conducted on the critical filling height of embankment.The obtained analytical formulae have good comparability and are validated.In addition, the necessity and rationality of the proposed applicable conditions are highlighted.The findings of the study illustrate that, the stiff crust has an overall influence, and the changes about thickness and Young's modulus of stiff crust could be simultaneously considered;the effect of lateral pressure coefficient is remarkable, and thus a real lateral pressure coefficient would be determined by in-situ test;moreover, the differences are significant with different strength criteria, and the effect of intermediate principal stress should be fully considered on the applicable conditions of formulation and filling height of embankment;the effect of high suction is different as compared with that of low suction.