Model Test Research on Bearing Mechanism of Underreamed Ground Anchor in Sand

Abstract

To improve the capacity of ground anchors, scholars and engineers worldwide have developed various types of underreamed anchors with expanded anchor parts. Underreamed anchors have a completely different mechanism from traditional shaft anchors. The expanded section of an underreamed anchor induces an end bearing force to endure the uplift force similar to a reversed pile. Therefore, the total resistance of an underreamed anchor includes friction and end bearing force. To clarify the bearing mechanism of underreamed anchors, a series of model tests were performed using fiber Bragg grating (FBG) sensors and the photogrammetry measuring method. Based on the tests, the distribution and development of the friction and end bearing force of the underreamed anchor model were acquired by the FBG sensors when being pulled out. Moreover, the deformation state of the soil around the anchor model was observed by the digital photogrammetry measuring method. Finally, the interaction mechanism between an underreamed anchor and surrounding sand was obtained, which was identified as the inherent reason for the distribution and development law of the resistance of the underreamed anchor in sand.

Structural parameter variation working on the performance of anti-uplift multibell underreamed anchors

“…Compared with a single enlarged anchor, a multibell underreamed anchor can significantly improve the uplift capacity 10 , and the influence of burial depth cannot be ignored 11 . Scholars have studied the position of the enlarged body on the anchor 12 , the enlargement shape 13 and the underreamed size 14 , 15 , but these factors have not been comprehensively considered.…”

The Influences of Bladder Properties on the Working Performance of the Multibladder‐Type Inflatable Anchor

“…Although the increase of the bladder space shows a positive effect on improving the ultimate pulling force and controlling the anchor deformation, such improvement is less efficient. erefore, it can be inferred that there may be an effective space, and it will produce a reverse effect when exceeding the space [47], which can be explained with that the working area of the bladder is limited, and the effect will be reduced once the bladder space is beyond the area. 6 Advances in Civil Engineering 3.5.…”

Study on the Influence of Radial Pressurization on Anchoring Performance of Bolts

“…Under grout injection, they can seamlessly expand and grout, ensuring continuous support. Guo Gang et al [8] using FBI sensors, monitored the frictional forces and end forces experienced by the hole-expanding anchor rod during pullout. Their findings revealed that the anchor rod's load-bearing capacity primarily stems from the end forces in the expanding section, and this capacity positively correlates with burial depth.…”