基于SMP破坏准则的岩土平面应变滑移线场理论

Slip Line Field Theory of Geotechnical Plane-strain Based on SMP Failure Criterion

选择平面应变破坏时的中间主应力σ2=(σ1σ3)～(1/2)更适合于岩土材料,本文提出了基于SMP破坏准则的岩土平面应变问题的滑移线场理论。该理论与基于Mohr-Coulomb破坏准则的滑移线场理论相比,由于考虑了中间主应力效应,能使土体强度参数提高15%～37%左右。通过算例计算验证表明:基于SMP破坏准则的滑移线Prandtl解比基于Mohr-Coulomb破坏准则的滑移线Prandtl解和Terzaghi解值都偏大;基于SMP破坏准则上限法计算的竖直坑壁临界高度同样比基于Mohr-Coulomb破坏准则计算的临界高度值大。该理论进一步发展了岩土平面应变滑移线场理论体系,应用于工程实际能产生一定的经济效益。

This paper demonstrates that intermediate principal stress σ2=√（σ1σ3） is more suitable for geotechnieal materials under plane strain failure condition, puts forward plane-strain slip line field theory based on the SMP failure criterion and points out the difference of the theory, in comparison with the slip line field theory based on Mohr-Coulomb failure, is that the intermediate principal stress effect is considered and the values of soil strength parameters are improved by about 15% to 37% . Case study shows that Prandtl solution value based on the new theory is greater to a certain degree than both Prandtl and Terzaghi solution values based on Mohr-Coulomb failure criterion, and the critical height of the vertical pit wall calculated based on SMP failure criterion is greater than the critical height calculated based on Mohr-Coulomb failure criterion. The theory developed in this paper promotes the geoteehnical plane strain slip line field theory, solves the problems of calculation methods considering real stress state in geotechnical engineering,and can produce some economic benefits in geotechnicaI engineering.