冻土与结构接触面冻结强度压桩法测定系统研制及试验研究
Development of measuring system by pile-pressing method and experimental study on adfreezing strength at interface between frozen soil and structure
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摘要: 为探究冻土与结构接触面冻结强度影响因素及其影响规律,依据接触面冻结强度传统定义,应用压桩法原理研制冻土与结构接触面冻结强度测定系统,并利用该系统开展多影响因素条件下接触面冻结强度测定试验研究。试验研究表明:冻土与结构接触面冻结强度呈现脆性破坏及应变软化,残余强度呈周期性波动及衰变等典型特征;冻土与结构接触面冻结强度受接触面温度和粗糙度影响显著,在试验温度范围内,分别呈线性和对数函数关系。利用埋设于抗压桩身侧面的微型土压力传感器,揭示了接触面压应力沿桩身分布规律,以及接触面压应力随冻结时间、剪切位移变化规律,并将其与接触面温度、冻结强度等变化规律进行对比分析和验证。Abstract: In order to study the influence factors and rules of adfreezing strength at the interface between frozen soil and structure, according to the traditional definition of adfreezing strength at the interface, a measuring system for determining the adfreezing strength by pile-pressing method is developed. Based on this system, a series of experimental studies on the adfreezing strength at the interface are carried out under various influence factors. The experimental results show that the adfreezing strength at the interface between frozen soil and structure exhibits brittle failure and strain softening, and the residual adfreezing strength is characterized by periodic fluctuation and decay. The adfreezing strength is significantly affected by the temperature and roughness of the interface, and they are linear and logarithmic functions respectively in the test temperature range. Using the micro-earth pressure sensor embedded at the side of the compression pile, the variation laws of the compressive stress at the interface with the freezing time, shear displacement and distribution along the pile are revealed, and then they are compared with and verified by those of the interface temperature and adfreezing strength.