饱和黏土中球(柱)孔瞬时扩张及超孔隙水压力研究

The Study of Expansion of Spherical Cavity and Excess Pore Water Pressure about the Spherical( Cylindrical) Cavity in Saturated Clay

因孔内压力瞬间加载到指定状态,球(柱)孔塑性区土体受力特征符合不固结不排水状态.基于此得出了针对饱和黏性土体中球(柱)孔扩张问题的屈服准则,此准则与Tresca准则形式相同.通过该屈服准则得出了饱和土体中球(柱)孔扩张问题的总应力场.然后通过弹性区、塑性区和弹塑性界面的特征求解出弹性区和塑性区超孔隙水压力;再根据有效应力原理,得出球(柱)孔扩张问题的有效应力场.最后利用推导出的理论成果,对沉桩引起的超孔隙水压力的实测值与计算值进行了比较分析.

As the internal pore pressure increases instantly to the target state,the stress state of the plastic zone around the spherical( cylindrical) cavity can be categorized as the three axle test non-consolidation and non-drainage( uu test). Based on which,a new yield criterion with the similar expression as Teresca criterion was proposed. The total stress field was first calculated utilizing the new criterion,the excess pore pressure field of elastic zone and plastic zone were then derived by the characteristics of the elastic zone,plastic zone and elastic-plastic interface,and the effective stress field was finally derived based on the effective stress principle. To validate the new criterion,a field test was conducted to investigate the excess pore water pressure around the pile surface,and the calculated results fit well with the test results.