锚杆-砂浆界面粘结滑移关系的试验研究与破坏过程解析

o research the bond-slip relationship between the bolt and cement mortar for rock foundation, the pull out test for short bolt in laboratory and uplift test for long bolt in field were carried out respectively. In laboratory, 6 kinds mix proportions of cement mortar were mixed to estimate the effect of the compression strength and sand ratio of mortar on bold-slip relationship. The best mix proportion is presented. Based on local deformation theory, a mathematics model is built, which could describe the change process of bolt-mortar interface undergo elastic, plastic softening and slip with uplift loading increase. The model was applied to analyze the field test data. The result show that the effective anchorage depth is a constant value if uplift loading is less than elastic ultimate loading, else it will increase, and attenuation degree of axis force with depth will slow because of interface plastic soften and cracking occur in top of bolt if uplift. Finally, the calculation formula of effective anchorage depth extend with uplift loading increase is presented.