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。 Transparent earth materials and particle image velocimetry (PIV) were used to study the mechanism of bolt pullout by physical model test. In the experiment, four kinds of anchors with different shapes, such as ordinary cylinder type, grenade type, canduna type and Christmas tree type, were used to test the disturbing regularity of each bolt with the anchorage section of anchorage to surrounding soil. Rod displacement and anchoring force, the ultimate bearing capacity and the failure mechanism of anchorage section are analyzed. The experimental results show that under the experimental conditions, except for the grenade-type anchor rod, the influence of various shapes of anchor bolts on soil horizontal displacement is relatively small compared with the vertical displacement before the bolt is extracted and destroyed. The vertical displacement of soil anchor is the largest, reaching 6.0 times the radius of anchor, which is 1.5 times larger than that of ordinary cylindrical anchor. The special-shaped anchor can effectively improve the anchor limit Bearing capacity can be increased by 66% ~ 91% than ordinary cylindrical anchor, of which the ultimate bearing capacity of Christmas tree type anchor is the largest. The effective length, effective cross-sectional area and effective diameter of anchorage section of anchor have direct bearing capacity The ultimate bearing capacity of anchor occurs between the initial failure of anchor interface and soil contact and the failure of the interface between anchor and soil at the interface between anchor section and soil, To the bottom of the development of the anchor to A-type anchor, for example, when the damage developed to the bottom of the anchor 1/3 position, the ultimate bearing capacity of the bolt peaked.