BOTDR分布式检测技术在复杂地层钻孔灌注桩测试中的应用研究

分析了Kagome格栅的等效刚度和屈服面. 其屈服面奇异，由4段直线围成. 利用该屈服面， 估算了Kagome具有I型、II型半无限大裂纹的裂尖塑性区，有限元计算验证了解析预测的 准确性. 与奇异屈服面相比，由Mises光滑屈服面给出的塑性区误差较大. 因此只有弹性情 况，可以将Kagome等效为各向同性；若材料塑性，或应力场奇异性较强，Kagome的强度依 赖于主应力方向，不能用各向同性模型来描述.

BOTDR BASED DISTRIBUTED STRAIN TEST ON BORED PILE BURIED IN COMPLICATED GEOLOGICAL GROUND

This paper presents the principals of bored pile test  using Brillouin optical time domain reflectometer (BOTDR). The formulas used to calculate the displacement, flexibility, axial force, skin friction and end-bearing resistance of piles were presented.  This technique was applied  to pile static load tests under complex geological conditions to detect the strains and internal forces in different types of bored piles. The  test results indicate that the abnormities of the strain distribution  along the piles were found at the positions of hole collapse, weak intercalation, and/or formation interface. On account of the differences of the field conditions and construction techniques, the end-bearing resistances didn't exert fully; the skin friction served as the main resistance to the loads.  The piles bearing characteristics were different each other. 