复杂环境下单支点内支撑结构力学变形特性研究

Study on Mechanics and Deformation Characteristic of Internal Support Structure with Single-support in Complex Environment

针对土质差、开挖深度大且环境复杂的城市基坑工程,探索单支点内支撑式围护结构的可行性,采用MIDAS GTS NX有限元软件,建立内支撑式排桩支护结构分析模型,重点研究排桩和支撑系统的内力及变形规律,结合现场监测数据,验证了复杂环境下单支点内支撑结构的安全性。研究结果表明:排桩呈现"鼓肚型"的变形特点,最大位移值约为开挖深度的0.13%,最大弯矩作用点约为开挖深度的0.79倍;冠梁最大位移位于每侧中部,支撑轴力的监测值与理论值基本一致。

In view of the city foundation excavation engineering with poor soil quality, large excavation depth and complex environment, to explore the feasibility of supporting structure with single-support, this paper used MIDAS GTS NX finite element software, established the analysis model of internal supportingpile structure, mainly studied the internal force and deformation law of row piles and supporting system, combined with field monitoring data, verified the security of the internal support structure with single- support in the complex environment. The research results show that the row of piles presented deformation characteristics of ＇ drum belly type ＇ , the maximum displacement is about 0.13% of the excavation depth, the maximum bending moment locates about 0.79 of excavation depth, the maximum displacement of the crown is located in the middle of each side, the monitoring value of the support axial force is basically consistent with the theoretical value.