软基堆载对邻近桥桩作用的数值分析

Numerical Analysis of Adjacent Bridge Piles Influenced by Surcharge Loads on Soft Foundation

基于研究软基堆载对邻近桥桩性状的复杂作用以及探讨对应软土地基加固方法的原因,采用有限元分析软件PLAXIS8.2对广深沿江高速公路深圳段海滨大道后施工堆载对邻近沿江高速桥桩性状的影响进行研究。通过对软基土层、堆载位置、堆载大小对邻近桥桩性状的影响,以及对两种软土地基加固方法效果进行比较分析,研究结果显示软基土层的塑性破坏是引起邻近桥桩应力和应变的根本原因,堆载距离相比堆载大小对邻近桥桩的性状影响更为明显。另一方面,对该滨海大道软土地基,采用水泥搅拌桩法(保证桩长、桩径)或强夯块石墩法(穿透亚黏土层)进行加固处理,都能有效减小土体的侧向位移和土体的沉降,减小对邻近桥桩的侧向作用,从而使变形控制在允许范围内以及保障桥桩安全使用。

In order to research the complex influence of surcharge load on soft soil on behavior of adjacent bridge piers and discuss the reinforcement methods for soft soil foundation,the FE analysis software Plaxis8. 2 is used to simulate the behavior of coastal expressway bridge piles influenced by the nearby surface loads in the post-construction of seaside avenue of Shenzhen section in Guangzhou-Shenzhen expressway. The influences of soft soil layer,location and weight of surcharge loads on the performance of the adjacent piles are compared,and the effects of 2 reinforcement ways of soft soil foundation are compared. The result shows that（ 1） the stress and strain of piles are caused by the plastic failure of soft soil layer,and the influence of surcharge load distance on the adjacent bridge piles is more obvious than the influence of surcharge load size;（ 2） for the coastal road,the lateral deformation of its soft foundation could be controlled in the allowable range to protect the safety service of the bridge piers through effectively reduce the lateral displacement and subsidence of the soil and reduce the side effect on adjacent bridge piers by using cement mixing pile method（ guarantee pile’s length and diameter） or tamping method（ penetrate clay layer） for consolidation.