Physical model test on the effect of different anchoring methods on the mechanical and deformation characteristics of anchored slide-resistant piles

Abstract

Anchored slide-resistant piles are one of the main supporting structures for landslides. To date, there is still a lack of systematic studies on the characteristics of the mechanics and deformation of anchored slide-resistant piles in weak-hard interbedded strata. This study taking weak-hard interbedded strata as the geological background, based on the self-developed flexible inclinometer and automatic loading system, the test system was constructed. Model tests of landslides reinforced by anchored slide-resistant piles were conducted, and the force and deformation characteristics of piles, anchor cables, and sliding mass were revealed in the process of increasing loading force. The influence of the layout of anchor cables on the force and deformation of the pile-anchor was analyzed. The influence mechanism of the stratum with weak-hard interbedded rock on the anchored slide-resistant piles was analyzed by numerical simulation. In addition, the theoretical analysis was carried out by taking the double-anchored pile as an example. The results show that: ① in the landslide-pile-anchor system, the deep displacement of the pile and sliding mass decreases with increasing pile depth, the growth rate of the rear is greater than that of the middle in the sliding mass, and the growth rate of the sliding mass is greater than that of the pile. ② The thrust sharing ratio of the pile-anchor undergoes four stages, which is approximately 9∶1 when it becomes stable. Meanwhile, the bending moment of the pile is distributed in an "S" shape under the action of the anchor cable tension, and the positive and negative bending moments are asymmetrical. ③ The growth rate of the anchor cable tension increases with the increase in the anchoring angle, and the influence of different anchoring angles on the internal force of the pile is mainly reflected in the loaded section. ④ The multianchored pile structure can share more thrust than the single-anchored pile, and the maximal bending moment values of the double-anchored pile and triple-anchored pile are reduced by 22.41% and 40.55%, respectively. ⑤ Compared with the homogeneous stratum, the stress of the bedrock at the interface between a weak and hard rock in the weak-hard interbedded stratum changes abruptly, and the thickness ratios of the weak rock and whether the pile bottom is embedded in hard rock all affect the axial force of the anchor cable and the pile-rock interaction to varying degrees.Meanwhile, the theoretical value for the internal force of the double-anchored pile is closer to the test result. The study results of this paper can provide evidence for the optimal design of projects for landslides reinforced by anchored slide-resistant piles in weak-hard interbedded strata.

Keywords

• landslide
• weak-hard interbedded stratum
• anchored slide-resistant pile
• model test
• thrust sharing ratio of pile-anchor