中文摘要：

采用透明土材料和粒子图像测速法（PIV）技术,通过物理模型试验研究锚杆拔出机理。在试验中采用普通圆柱型和手榴弹型、糖葫芦型和圣诞树型3种异型共4种不同形状锚固段锚杆,测试获得各锚杆随锚杆锚固段上移对周围土体的扰动规律、锚杆位移与锚固力变化曲线,分析各锚杆锚固段的极限承载力与锚固段破坏机理。试验结果分析表明：在本文试验条件下,在锚杆拔出破坏前,除了手榴弹型锚杆外,各种形状锚杆对土体水平位移影响相对于竖向位移均较小,糖葫芦型和圣诞树型锚杆对土体的竖向位移影响范围最大,达到6.0倍锚杆半径,比普通圆柱型锚杆对土体竖向位移影响范围大1.5倍;异形锚杆可以很有效的提高锚杆极限承载力,比普通圆柱型锚杆可提高66%～91%,其中圣诞树型锚杆的极限承载力最大;锚杆锚固段的有效长度、有效横截面积、有效直径对其极限承载力有直接影响;锚杆极限承载力值是发生在锚杆锚固段与土体接触的界面开始破坏到完全破坏之间,锚杆锚固段与土体接触界面发生破坏,是从锚杆自由段部位开始逐渐往锚杆底部发展,以A型锚杆为例,当破坏发展到距锚杆底部1/3的位置时,锚杆极限承载力达到峰值。

英文摘要：

A small-scale physical modelling system is developed to study the pull-out mechanism of embedded soil nails based on transparent soil and particle image velocimetry（PIV）. Four types of soil anchorages, common cylindrical anchorage, hand grenade shape anchorage, round bead string shape anchorage and Christmas-tree shape anchorage, are set in the experiment to observe the soil displacement impact areas and load-displacement curve. Then the maximum uplift capacity and the failure mechanism of soil anchorages are discussed. From the results, it is shown that before failure happens, all horizontal displacements of soil anchorages are relatively small compared to vertical displacements, except for the hand grenade shape anchorage. The vertical displacements of the round bead string shape anchorage and Christmas-tree shape anchorage have the larger vertical displacement impact area, and both reach 6.0R. The profiled anchorage can effectively provide 66%～91% more force than the normal cylinder anchorage, and the Christmas-tree shape anchorage has the largest uplift load. The anchorage length and effective radius are directly related with the anchorage pull-out resistance. The maximum uplift capacity happens between the pull-out starting and full failure of the soil-soil anchorage interface. When the soil-anchorage interface begins to fail, failure first occurs at the top of soil anchorage, then develops to the bottom along the soil anchorage body. Take soil anchorage type A for an example, when the failure develops 1/3 of its own length to its bottom, the uplift capacity reaches the peak value.