ZHENG C, SHANG W C, SONG H X,et al.Study on the load-bearing behavior of rock-socketed piles under multidirectional horizontal cyclic loading[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(4):11-21.

doi:10.16186/j.cnki.1673-9787.2026020003

Received:2026/02/02

Revised:2026/04/30

Published:2026/06/17

Study on the load-bearing behavior of rock-socketed piles under multidirectional horizontal cyclic loading

Zheng Can1, Shang Wenchang2, Song Hexing1, Liu Junwei2,3, Lai Huaiyuan1, Hu Yukun2, Qi Guangyu2, Zhang Yingyu2, Dai Xingke2,4

1.Guangdong Electric Power Design Institute Co.， Ltd.， China Energy Engineering Group， Guangzhou  510670， Guangdong， China;2.School of Civil Engineering， Qingdao University of Technology， Qingdao  266000，Shandong，China;3.Qingdao Key Laboratory of Intelligent Port Construction and Operation and Maintenance， Qingdao  266520，Shandong，China;4.Shanghai Municipal Engineering Design Institute （group） Co.， Ltd.， Shanghai  200092， China

Abstract: Objectives The horizontal load-bearing mechanism of rock-socketed single piles under different loading paths remains unclear. Therefore， this study investigates the load-bearing behavior of rock-socketed piles subjected to multidirectional horizontal cyclic loading.  Methods Based on a self-developed horizontal cyclic loading test apparatus， field horizontal cyclic loading tests were conducted in four loading directions (0°, 45°, 90°, and 135°）to investigate the horizontal load-bearing behavior of rock-socketed piles under multidirectional cyclic loading.  Results The results indicate that the horizontal displacement of the pile decreases with increasing embedded depth. Multidirectional horizontal cyclic loading subjects the surrounding rock mass to cyclic pressures from different directions， resulting in plastic deformation around the pile. The plastic deformation gradually stabilizes with variations in loading direction and the number of loading cycles. The increase in pile bending moment is mainly concentrated within the first 15 loading cycles. After 1 000 cycles， the bending moment no longer increases. The fixity provided by the weathered rock layer is mainly concentrated within the embedded depth range of 0-1.5 m. The peak surrounding rock resistance occurs at an embedded depth of 0.5 m and remains unchanged with the number of loading cycles. As the number of loading cycles increases， the surrounding rock resistance gradually stabilizes. The p-y curves under 0°， 45°， and 90°horizontal cyclic loading are approximately linear， whereas the p-y curve under 135° loading exhibits a nonlinear response. After more than 15 loading cycles， the surrounding rock reaction begins to decrease， accompanied by a reduction in the stiffness of the pile-rock interface.  Conclusions Multidirectional cyclic horizontal loading causes the horizontal load-bearing mechanism of rock-socketed piles to exhibit pronounced path-dependent characteristics， with the shallow strongly weathered rock mass playing a dominant role in controlling the bearing performance. Multidirectional cyclic loading accelerates the degradation of the equivalent stiffness of the pile-rock system and promotes the development of a nonlinear p-y response. In the later loading stages， rock mass failure becomes the key factor limiting the horizontal bearing capacity of rock-socketed piles.

Key words:multidirectional horizontal cyclic loading;rock-socketed pile;surrounding rock resistance;- curve