SHAO G B, FU T G, JIANG T Q, et al． In-situ test study on compressive bearing capacity of PHC pipe pile post grouting in alluvial strata of the lower Yellow River[J]. Journal of Henan Polytechnic University( Natural Science) ，doi: 10.16186/j.cnki.1673-9787. 2025010003.

doi: 10.16186/j.cnki.1673-9787. 2025010003.

Received： 2025-01-03

Revised： 2025-03-04

Online： 2025-10-14

In-situ test study on compressive bearing capacity of PHC pipe pile post grouting in alluvial strata of the lower Yellow River (Online)

SHAO Guangbiao^1,3，FU Tangguo¹，JIANG Tianqi²，CHEN Linlin⁴，LIU Yuewei⁴

1 School of Civil Engineering, Shandong Jianzhu University, Jinan 250101；2 Shandong Dingxing Foundation Engineering Co., Ltd., Jining 272000；3 Key Laboratory of Building Structure Reinforcement and Underground Space Engineering, Ministry of Education, Shandong Jianzhu University, Jinan 250101；4 Shandong Jianzhu University Engineering Appraisal and Reinforcement Research Institute Co., Ltd., Jinan 250013

Abstract: Objectives In order to solve the problems of poor soil squeezing effect and low side resistance of PHC pipe pile caused by short deposition time and high sensitivity of alluvial strata in the lower reaches of the Yellow River, the experimental study on the compressive bearing capacity of PHC pipe pile after grouting under this stratum condition was carried out. Methods The post-grouting method and the length of the test pile were selected as variables, and the in-situ test was carried out based on a project under construction. The post-grouting methods of the test design are pile end post-grouting and pile end pile side compound post-grouting, and a non-grouting control group is set. The construction piles are 15 m and 19 m in length, three test piles in each group. The bearing layers are silty clay and silty soil, respectively. Each group includes composite post-grouting pile, post-grouting pile at pile end and non-grouting pile. The strain sensor is pasted on the pile body of the test pile, and the reaction force meter is installed at the pile end. Combined with the static load test, the variation law of the pile body is explored.

Results The ultimate bearing capacity of the composite post-grouting test piles increased by 77% (15 m) and 55%(19 m) respectively, and the ultimate bearing capacity of the post-grouting test piles increased by 26% (15 m) and 19%(19 m ) respectively. After the compound post-grouting, the lateral resistance of the silt layer is increased by 96%, the lateral resistance of the silty clay layer is increased by 64%, and the relative displacement of the pile-soil required for the lateral resistance of the lower soil to reach the limit is increased from 5~7 mm to 15~20 mm. When the silt is used as the bearing layer, the effect of improving the end resistance is better than that of the silty clay. The end resistance of the composite post-grouting pile type is increased by 1.84 times, and the end resistance of the post-grouting pile type is increased by 1.52 times. Conclusions The post-grouting technology of PHC pipe pile is suitable for alluvial strata in the lower reaches of the Yellow River. It can effectively improve the compressive bearing capacity of PHC pipe pile, improve the stability of pile body, and enhance the elastic-plastic deformation characteristics of pile-soil system. In this paper, compound post-grouting boosts PHC pipe piles' end and side resistance ratios, not lower than those of post-grouted cast-in-place piles in the code. So, it can directly guide engineering practice.

Key words: alluvial strata in the lower Yellow River; PHC pipe pile; pile end post grouting; pile end pile side compound post grouting; in-situ test; compressive bearing characteristic