锚–土界面剪切蠕变试验及其经验模型研究

为了研究土层灌浆锚杆锚–土界面剪切蠕变特性,提出了一种新颖的锚–土界面蠕变试验方法,并设计制作了相应的试验装置。通过分级加载蠕变试验,得到了锚–土界面剪切蠕变曲线,采用"陈氏加载法"将分级加载曲线转化为分别加载曲线。分析试验结果发现,锚–土界面衰减蠕变阶段的位移–应力关系采用幂函数、位移–时间关系采用改进双曲线函数拟合效果最好。由此建立了适合锚–土界面衰减蠕变阶段的经验蠕变模型,该模型可更好地拟合并预测衰减蠕变曲线。同时,在该衰减蠕变模型基础上,引入Kachanov损伤因子考虑加速蠕变损伤,建立了适合锚–土界面加速蠕变阶段的加速(损伤)蠕变模型。

Tests on shearing creep of anchor-soil interface and its empirical model

A novel creep test method for anchor-soil interface is proposed to investigate the shearing creep characteristic of anchor-soil interface for grouted anchors in soil. The corresponding test apparatus is also designed and manufactured. The shearing creep curves of anchor-soil interface in multi-stage loading are obtained, and they can be transformed to the creep curve at each specific loading level by employing Chen's method. The results suggest that the power function and modified-hyperbolic function demonstrate good performance in the fitting of displacement-stress and displacement-time relationships respectively. A novel empirical creep model for anchor-soil interface is established based on these fitting techniques, capable of fitting and predicting the decayed creep curve at each stress level in a better agreement. On the basis of this decayed creep model, the accelerating (damage) creep model applicable to accelerating creep phase is proposed by introducing the Kachanov damage factor to represent the accelerating creep damage for anchor-soil interface.