Research on the Vertical Bearing Capacity of Concrete-Filled Steel Tube Composite Piles by Mixing Method
To address the issues of low shear strength, susceptibility to eccentricity, and alignment difficulties in post-inserted core piles, a new type of steel tube concrete integrated mixing composite pile has been independently developed. This pile type replaces the conventional mixing pile shaft with a...
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MDPI AG
2025-04-01
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| author | Chaosen Tian Ping Li Rongxi Yv Yixin Li Bohan Li |
| author_facet | Chaosen Tian Ping Li Rongxi Yv Yixin Li Bohan Li |
| author_sort | Chaosen Tian |
| collection | DOAJ |
| description | To address the issues of low shear strength, susceptibility to eccentricity, and alignment difficulties in post-inserted core piles, a new type of steel tube concrete integrated mixing composite pile has been independently developed. This pile type replaces the conventional mixing pile shaft with a larger diameter steel tube equipped with mixing blades. After forming the external annular cement mixing pile, the steel tube is retained, and the hollow core is filled with concrete. To thoroughly explore the vertical compressive bearing characteristics of the steel tube concrete mixing composite pile and clarify its vertical compressive behavior, static load field tests and PLAXIS 3D finite element numerical simulations were conducted on four test piles of different sizes to analyze the vertical bearing performance of the steel tube concrete mixing composite pile. The research results indicate that for a composite pile with a length of 40 m, an outer diameter of 1000 mm, and a steel tube diameter of 273 mm, the ultimate bearing capacity of a single pile is 7200 kN, with the steel tube concrete core contributing approximately 81% of the vertical bearing capacity, while the cement mixing pile contributes around 19%. Based on the characteristic that the maximum axial force is concentrated in the upper half of the pile length, an innovative variable-diameter design with a reduced wall thickness of the steel pipe in the lower part of the pile was proposed. Practical verification has shown that, despite the reduced material usage, the load-bearing capacity remains largely unchanged. This effectively validates the feasibility of the “strong upper part and weak lower part” design concept and provides an effective way to reduce construction costs. |
| format | Article |
| id | doaj-art-d538188dbf0c41aeba0b715587e73eb8 |
| institution | OA Journals |
| issn | 2076-3417 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | MDPI AG |
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| spelling | doaj-art-d538188dbf0c41aeba0b715587e73eb82025-08-20T01:49:20ZengMDPI AGApplied Sciences2076-34172025-04-01159502210.3390/app15095022Research on the Vertical Bearing Capacity of Concrete-Filled Steel Tube Composite Piles by Mixing MethodChaosen Tian0Ping Li1Rongxi Yv2Yixin Li3Bohan Li4State Key Laboratory of Precision Blasting, Hohai University, Nanjing 210024, ChinaState Key Laboratory of Precision Blasting, Hohai University, Nanjing 210024, ChinaChina Railway Shanghai Design Institute Group Co., Ltd., Shanghai 200070, ChinaState Key Laboratory of Precision Blasting, Hohai University, Nanjing 210024, ChinaState Key Laboratory of Precision Blasting, Hohai University, Nanjing 210024, ChinaTo address the issues of low shear strength, susceptibility to eccentricity, and alignment difficulties in post-inserted core piles, a new type of steel tube concrete integrated mixing composite pile has been independently developed. This pile type replaces the conventional mixing pile shaft with a larger diameter steel tube equipped with mixing blades. After forming the external annular cement mixing pile, the steel tube is retained, and the hollow core is filled with concrete. To thoroughly explore the vertical compressive bearing characteristics of the steel tube concrete mixing composite pile and clarify its vertical compressive behavior, static load field tests and PLAXIS 3D finite element numerical simulations were conducted on four test piles of different sizes to analyze the vertical bearing performance of the steel tube concrete mixing composite pile. The research results indicate that for a composite pile with a length of 40 m, an outer diameter of 1000 mm, and a steel tube diameter of 273 mm, the ultimate bearing capacity of a single pile is 7200 kN, with the steel tube concrete core contributing approximately 81% of the vertical bearing capacity, while the cement mixing pile contributes around 19%. Based on the characteristic that the maximum axial force is concentrated in the upper half of the pile length, an innovative variable-diameter design with a reduced wall thickness of the steel pipe in the lower part of the pile was proposed. Practical verification has shown that, despite the reduced material usage, the load-bearing capacity remains largely unchanged. This effectively validates the feasibility of the “strong upper part and weak lower part” design concept and provides an effective way to reduce construction costs.https://www.mdpi.com/2076-3417/15/9/5022soft soil foundationfield testbearing capacityvariable diameter |
| spellingShingle | Chaosen Tian Ping Li Rongxi Yv Yixin Li Bohan Li Research on the Vertical Bearing Capacity of Concrete-Filled Steel Tube Composite Piles by Mixing Method Applied Sciences soft soil foundation field test bearing capacity variable diameter |
| title | Research on the Vertical Bearing Capacity of Concrete-Filled Steel Tube Composite Piles by Mixing Method |
| title_full | Research on the Vertical Bearing Capacity of Concrete-Filled Steel Tube Composite Piles by Mixing Method |
| title_fullStr | Research on the Vertical Bearing Capacity of Concrete-Filled Steel Tube Composite Piles by Mixing Method |
| title_full_unstemmed | Research on the Vertical Bearing Capacity of Concrete-Filled Steel Tube Composite Piles by Mixing Method |
| title_short | Research on the Vertical Bearing Capacity of Concrete-Filled Steel Tube Composite Piles by Mixing Method |
| title_sort | research on the vertical bearing capacity of concrete filled steel tube composite piles by mixing method |
| topic | soft soil foundation field test bearing capacity variable diameter |
| url | https://www.mdpi.com/2076-3417/15/9/5022 |
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