Failure mechanism analysis of soil behind a perforated rigid wall by the upper bound method with rigid translatory moving element
The stability issue of soil behind the underground rigid continuous wall with openings under overload has broad applications.Considering the width of rectangular opening on the wall is large enough,and the interface between rigid wall and soil is completely smooth,refer to the idea of the rigid block upper bound method to assume simplified failure mechanism of retained soil behind rigid diaphragm wall transformed into an initial triangular mesh.An iterative cyclic approach that involves mesh update such as nodes addition,elements reduction,diagonal swapping,and layered element refinement was proposed.Stability analysis of retained soils behind underground walls with an opening was studied by using upper bound method with rigid translatory moving element.Based on multi-level nonlinear programming,more accurate upper bound solutions for the critical loading factor coefficient σs/c were obtained.Based on these solutions,slip-line failure mechanisms behind rigid diaphragm wall and quantitative ranges and expanded boundaries were defined.In subsequent computation,the upper bound solutions for the critical overloading coefficient σs/c in form of charts was generated for various parameters.The results are drawn as follow.1)Typical failure mechanism characteristics behind the rigid wall are characterized by overall subsidence area above soil above and at the opening.The failure area is mainly in rigid block groups of densely slip-line area in the core region in front of the opening,and primary sliding surfaces on the periphery.The critical overloading factor σs/c increases with an increase in the internal friction angle ϕ of the soil,with a considerable increase in subsequent procedure.σs/c exhibits an approximate linear increase with an increase in the ratio of opening depth to width(C/D).Compared to ϕ and C/D,the variation in soil density parameter γD/c has mild impact on σs/c.With an increase in γD/c,σs/c increases.It shows an approximate linear decrease.The influence of the shear dilation angle parameter ψ/ϕ on σs/c is closely related to the increase in ϕ.The results of this study provide data support for the quantitative analysis of stability failure mechanisms,research in failure mechanisms,and the adoption of treatment measures in practical engineering for retained soil behind rigid diaphragm walls.
国家科技期刊平台
NSTL
万方数据
