Steel-strip reinforced earth walls stabilize through the pullout resistance of the reinforcements. Soil dilation during the pullout of ribbed reinforcements may contribute to the evolution of pullout resistance; however, few studies have clarified this mechanism by investigating how soils behave with increasing pullout displacement. The ribs of the reinforcements enhance the pullout resistance, although the influence of the rib dimensions on the evolution of pullout resistance with increasing pullout displacement has not been sufficiently revealed. In the present study, a triaxial pullout apparatus is developed and pullout tests are conducted using ribbed reinforcements with different rib-inclination angles under isotropic stress. The displacement and strain fields in the soils during the pullout of the reinforcements are investigated by X-ray micro CT and a digital image correlation technique. It is found that larger rib-inclination angles provide higher pullout resistance at an early stage of the pullout because of the higher bearing resistance related to the more significant soil densification above the ribs. With increasing pullout displacement, the reinforcements with different rib-inclination angles come to behave as almost one in the same since a rigid soil wedge related to the passive soil failure is generated above the ribs. This tendency results in similar soil deformation characteristics and pullout resistance levels for every reinforcement beyond the soil failure state, although the rib-inclination angles are different.

钢带加固土墙通过加固物的拉拔阻力来稳定。拔出带肋钢筋时的土壤膨胀可能会导致拔出阻力的演变；然而，很少有研究通过研究土壤如何随着拔出位移的增加而阐明这一机制。加强筋的肋增强了拉拔阻力，尽管肋尺寸对拉拔阻力随拉拔位移增加的演变的影响尚未得到充分揭示。在本研究中，开发了一种三轴拉拔装置，并在各向同性应力下使用具有不同肋倾角的带肋钢筋进行拉拔试验。通过X射线显微CT和数字图像相关技术研究了钢筋拔出过程中土壤中的位移和应变场。发现较大的肋骨倾斜角在拉拔的早期阶段提供更高的拉拔阻力，因为与肋骨上方更显着的土壤致密化相关的承载阻力更高。随着拉拔位移的增加，由于在肋上方产生了与被动土破坏相关的刚性土楔，因此具有不同肋倾角的钢筋表现得几乎相同。尽管肋骨倾斜角度不同，但这种趋势导致超出土壤破坏状态的每个加固物的土壤变形特征和抗拔力水平相似。