斜坡地基静力触探试验离散元分析

Discrete Element Method Analysis of Cone Penetration Tests on Sloping Ground

摘要:

通过二维离散元模拟斜坡地基静力触探试验,研究试验过程中锥尖阻力的变化以及斜坡地基的宏微观力学响应。结果表明:归一化锥尖阻力峰值在坡角较小时无明显提升,在坡角足够大时提升明显,稳定值随着坡角增大略微减小,说明斜坡边界对表层土力学性能影响明显,而对深层土影响较弱;锥尖贯入过程中,斜坡地基探杆两侧土体变形不对称,坡上一侧膨胀,坡下一侧压缩,不对称性随着坡角增大而增大;贯入到表层时,探杆两侧微观接触力链不对称,坡上一侧具有更大应力,但当贯入到深层时力链趋向于对称,其临界深度随着坡角增大而增大,与坡角呈近似线性关系。

Abstract:

Much investigative work has been conducted on cone penetration tests on flat ground; however,research on cone penetration tests on slopping ground is scarce.Two-dimensional discrete element method simulation of cone penetration tests on sloping ground were performed,in which the tip resistance and micro-macro mechanical behavior of the cut slope was studied.The experimental results showed that the peak value of the normalized tip resistance does not increase when the slope angle is below a specific value,but increases when the slope angle is high.Nevertheless, the residual value decreases slightly with the increase of slope angle,indicating that the boundary of cut slope greatly affects the regolith,not the subsoil.As penetration proceeds,the deformation of the soil at the two sides of the cone is asymmetric with dilation on the upslope and compression on the downslope.This asymmetry increases with the slope angle.As the cone penetrates into the regolith,the force chains at different sides of the cone are asymmetric with higher stress on the upslope.However,as the penetration proceeds into the subsoil,the force chains tend to be symmetric.The critical depth of penetration symmetry increases with slope angle forming a linear relationship.