扩底抗浮锚杆的抗拔承载特性试验研究

Field Tests and Research on Uplift Capacity of Expanded Anchor

我国东南沿海地下水位普遍较高,位于该地区的筏形基础大都需要考虑基础抗浮问题。笔者研发了一种采用向底部空腔二次注浆扩孔形成扩底截面的扩底抗浮锚杆,在此基础上,就该装置的抗拔承载性状及荷载传递机理进行了现场试验研究,给出了实际应用的预期效果。测试结果表明,该装置在软土地基中扩孔效果良好,其承载性能显著优于普通锚杆。试验结果揭示了具有扩底截面的抗浮锚杆的轴向应力和剪应力分别随荷载水平和锚固深度变化的分布。相比较而言,扩底抗浮锚杆具有布置灵活,构造、受力合理等特点,可作为软土地区的基础抗浮设计的优选方案。

The groundwater level along the southeast coast of China is generally high.The problem of foundation anti-floating needs to be concerned for the raft foundations in southeast China.A new type of post-grouting expanded anchor that using constraints to form an enlarged by the soil bags was designed.A Full-Scale test about this anchor were carried out.The uplift capacity and mechanical characteristics of this device was acquired by step-loading,and expected effects of this expanded anchor were given out.The test results show that the device has good hole expansion effect in soft soil foundation,and its bearing performance is significantly better than that of ordinary anchor bolt.The test results reveal the distribution of axial stress and shear stress of anti floating anchor with enlarged bottom section with load level and anchorage depth,respectively.In comparison,the expanded bottom anti floating anchor rod has the characteristics of flexible layout,reasonable structure and stress,and can be used as the optimal scheme for foundation anti floating design in soft soil area.