桩锚式支护桩内力和变形测试研究

Test Study on the Internal Force and Deformation for Anchored Bracing Pile

为了研究桩锚式支护桩的内力和变形特性,对桩身钢筋应力和圈梁的侧向位移进行了监测,得到了桩身的弯矩分布图和侧向位移分布图。监测结果表明:随着开挖深度的增加,基坑内侧的最大弯矩逐渐增大,而且其作用位置向下偏移;设置锚杆改变了桩身弯矩的分布特征,最大弯矩的数值减小,其作用点位置下移,桩身的侧向位移显著减小;基坑开挖过程中基坑开挖的空间效应显著,基坑测试段中部的桩身弯矩较其他部位桩身的弯矩值大,且支护段中部的侧向位移最大;基坑开挖至基底后,桩身负弯矩的最大值发生在坑底内侧附近,本次测试结果可为桩锚支护结构的设计提供可靠的依据。

In order to study the internal force and deformation for anchored bracing pile,stress of steel bar in the pile had been monitored,based on the stress of steel bar,the moment distribution along the bracing pile was obtained,the lateral displacement of pile top was also monitored during the excavation.The test results suggested that the maximum moment of inner side of foundation pit increased with the increasing of foundation pit depth,the position of its action point moved downward.The character of moment distribution was changed by installation of anchor. Using anchor to control the lateral displacement of foundation pit is effective. The space effect of the process of excavation was obvious, the maximum moment of pile lies at middle part was larger than that at other part, the lateral displacement happened in the middle part was also the most. As the excavation finished, the maximum moment of pile occurred about at the bottom of foundation pit.