深基坑支护方案比选的效率系数数值模拟与评判

摘要

为给深基坑工程设计方案的选择提供便于应用的判别方法 ,以某紧邻地铁车站深基坑工程为实例 ,运用大型通用有限元软件ABAQUS建立了三维数值分析模型 ,对不同支护方案下基坑施工的实际过程进行了数值模拟 ,提出了以桩长效率系数与桩径效率系数作为评判支护方案的支护效果及经济性的标准 .数值模拟结果表明 :当桩长效率系数与桩径效率系数增大时 ,支护结构侧向位移逐渐减弱 ,支护作用逐渐增强 ,但二者并非越大越好,在桩长效率系数与桩径效率系数达到最大值前,支护作用均随二者的增加而显著增强 ,当二者达到最大值后 ,支护作用的增强效果不再显著,经济性逐渐减弱 ,而二者达到最大值时对应的桩长和桩径即为最优值 .%In order to provide a method of discriminant for easy application for design scheme of deep foundation pit engineering selection ,one deep foundation pit adjacent to the subway station is taken as an example .The large-scale general finite element software ABAQUS is used to establish three-dimensional numerical analysis model .The actual process of building foundation construction under the excavated hole with different supports and protections plans is simulated .The standard of the supporting effect and economy of using the pile length and pile diameter coefficient of efficiency is put forward as the evaluation of support scheme .The results show :With the increase of the pile length efficiency coefficient and pile diameter efficiency coefficient ,the supporting structure of the lateral displacement decreases gradually ,and the supporting effect is enhanced .However ,it is not the more the better .Before the pile length efficiency coefficient and pile diameter efficiency coefficient reach the maximum values ,the support effect increases along with the two and significantly enhances .When they reach the maximum values ,the supporting enhancement is no longer significant ,and the efficiency weakens gradually .When the two reach the maximum values ,the corresponding pile length and pile diameter become the optimum values .