后植筋技术在CFG桩复合地基静载试验中的应用

Application of post⁃installed steel bars technology in static load test of CFG pile composite foundation

为了克服传统堆载法静载试验的局限性,提出在试验桩周围工程桩上后植钢筋的方式组成反力系统的新型静载试验。以某高层建筑CFG桩复合地基为例,详细介绍了后植筋锚桩反力系统的设计。该新型反力系统成功应用于最大加载量为4498.2kN的CFG桩复合地基静载试验,相比传统堆载法可减小使用配重91.7%,节约费用78.8%。该新型反力系统中各后植筋轴力表现为靠近主梁的较大,远离主梁的较小,最远端后植筋轴力发挥不充分。后植筋锚桩反力法对于静载试验具有较重要的工程实用价值。

In order to overcome the limitation of static load test of traditional surcharge method,a new static load test of reaction system was proposed by post⁃installed steel bars on the engineering pile around the test pile.Taking the CFG pile composite foundation of a high⁃rise building as an example,the design of the reaction system of the anchor pile with post⁃installed steel bars was introduced in detail.The new reaction system has been successfully applied to the static load test of CFG pile composite foundation with maximum load of 4498.2kN.Compared with tradition surcharge method,the use of counterweight can be reduced by 91.7%and the cost can be saved by 78.8%.In the new reaction system,the axial force of each post⁃installed steel bars is larger near the main beam and smaller away from the main beam,and the axial force of the farthest post⁃installed steel bars is not fully played.The new reaction method of anchor pile with post⁃installed steel bars has important engineering practical value for static load test.