基于BOTDA的桩锚结构受力分析研究

Research on Force Analysis of Pile-anchor Structure Based on BOTDA

文中基于布里渊光时域分析(BOTDA)技术对桩锚结构的微应变监测,探讨其在深基坑工程中的受力特征。通过研究应变光缆对基坑开挖全过程的测量数据,反向分析支护桩的受力情况。结果表明,基坑变形小,整体稳定;监测应变反推的桩身内力分布及传递规律明显且贴切实际,在桩锚结构上的锚索作用位置及坑底以下2.5 m处的弯矩相对最大;土压力的分布规律与常规不一致,当存在多排预应力锚索时,支护桩上作用的土压力值小于经典土压力理论计算值。

Based on the micro-strain monitoring of pile-anchor structures based on BOTDA technology,its stress characteristics in deep foundation pit engineering is discussed.Through the data of the whole excavation process of the foundation pit by the strain optical cable,the stress situation of the supporting pile is studied by the back analysis method.The results show that the deformation of the foundation pit is small and the whole foundation is stable.The distribution and transmission law of the internal force of the pile body is obvious and in line with the actual situation,and the bending moments are relatively maximum at the action position of the anchor cable on the pile anchor structure and 2.5 m below the pit bottom.In addition,the distribution law of earth pressure is inconsistent with the conventional one.When there are multiple rows of prestressed anchor cables,the earth pressure acting on the supporting pile is less than the calculated value of classical earth pressure theory.