ANALYSIS ON HEAVE-RESISTANT STABILITY CONSIDERING THE EFFECT OF EXCAVATION WIDTH

In recent years, more and more narrow excavations have been executed accompanying the construction of subway stations and underground galleries. The existing calculation methods of heave-resistant stability are mainly based on the soil bearing capacity limit equilibrium theory and slip circle method around the bottom support, ignoring the effect of excavations width. This paper performs numerical simulation of deep foundations under different widths, and puts forward a new model for the calculation of heave-resistant stability in narrow excavation based on the regularity of critical slip surface. The coefficient of passive earth pressure when the width of the backfill is limited is modified. In this case, the paper analyzes the effect of width of excavation and embedded depth of retaining walls. The study shows that the heave-resistant stability of narrow excavation is higher and the effect of width in sandy foundation is more obvious than in mucky soil. The theoretical method is applied to an engineering instance and experimental data confirm its rationality.