现场锚定板拉拔试验的数值模拟需考虑施工过程中复杂几何特征三维部件之间的多重连接接触和严重的局部大变形,一般的数值模型很难获得理想的收敛效果.本文以某原型多锚定板挡土墙室内试验为数值模拟对象,通过分析锚定板拉拔过程中的力学变形特性,系统提出了锚定板拉拔三维问题平面应变化的思路.首先针对试验砂土-ε3/ε1与径向应变-ε3之间不具有线性关系的特征,修正了邓肯-张E-模型;其次基于承载力相等原则,分别建立了锚杆、锚定板的等效计算公式,并进一步基于太沙基地基极限承载力模型对锚定板进行了形状调整;最终建立了锚定板拉拔试验的等效平面应变数值模型,并对四种工况进行了全过程模拟.结果表明:计算值与试验值吻合较好;3种工况下锚定板极限承载力的计算平均值与实测值的误差仅在1%左右.这说明本文所提出的模型等效方案和数值模拟取得了较好的效果,其思路和具体实施方法可为类似工程的数值模拟提供参考.%For the reasons of multiple contacts between complex geometry 3D units and severe local large deformation during the construction process,the numerical simulation of anchor plate field pullout test is hard to obtain convergent results.A Full-size multi-anchor retaining wall was studied to propose a method for the plane strain modeling of 3D anchor plate pullout problem based on the analysis of mechanical deformation characteristics in the pullout process.Firstly,the Duncan-Chang E- model was revised to compatible with the nonlinear relationship between-ε3/ε1 and-ε3 of the tested sand;Secondly,the theoretical formulas were established to modify the sizes of anchor rod and plate respectively according to the principle of equal bearing capacity.The shape of anchor plate was further adjusted based on Terzaghi ultimate bearing capacity theory of foundation.Lastly,the equivalent plane strain numerical model of full-size anchor plate retaining wall pullout test was established to simulate the whole pullout course of four experimental conditions.The result shows that:the calculated curve agree well with the experiment ones.The error between average calculated value and test ones of ultimate bearing capacity is only about 1%,which means that the equivalent program and simulation have made a good effect.This specific implementation method can provide a reference for the numerical simulation of similar projects.
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