既有施工基坑加深开挖下复合桩锚支护结构分析

介绍了一种用于加固既有施工基坑加深开挖的复合桩锚支护结构,并使用有限元方法对复合桩锚支护结构变形与基坑整体稳定性进行了深入研究。研究结果表明:随着新旧支护桩间距增大,新桩与旧桩最大水平位移均减小;随着新桩支护高度增加,新桩最大水平位移增大,而旧桩最大水平位移基本不变。基坑整体稳定性安全系数随着新旧支护桩间距增大而增大,而与新桩支护高度基本无关,新旧支护桩间距对基坑滑裂面形式起控制作用。既有施工基坑加深开挖采用复合桩锚支护结构加固时,可通过增大新旧支护桩间距和减小新桩支护高度来控制基坑变形和提高基坑整体稳定性。监测数据表明该基坑支护结构加固设计方法是可行的,具有一定的参考价值。

Analysis on deformation and stability of foundation pit deeper excavation reinforced by composite pile-anchor supporting structure

We introduce the composite pile-anchor support structure that is used to reinforce a foundation pit deeper excavation project. The deformation of the composite pile-anchor retaining structure and the stability of foundation pit are studied through the finite element numerical simulation method. The results show that the maximum horizontal displacement of new piles and the old one decrease with the increasing of old and new pile spacing; with the increasing of the height of new pile, the maximum horizontal displacement of new piles increases, while the old ones basically remain the same. The stability factor increases with the increasing of old and new pile spacing, while it almost has no relation with the height of new pile. The old and new pile spacing has control effect on the slide surface pattern. For the reinforcement of the foundation pit deeper excavation, the spacing increase of old and new piles and decrease of new pile height can effectively control the deformation. The monitoring data shows that the strengthening method of the foundation pit support structure is feasible, which has reference value.