Effect of Pile Spacing on Load Bearing Performance of NT-CEP Pile Group Foundation

The NT-CEP pile is an innovative type of pile that builds upon the conventional concrete straight-hole cast-in-place pile. It primarily consists of two components: the main pile and the bearing plate. The key factors influencing its load-bearing capacity include the pile diameter, the cantilever dim...

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Main Authors: Yongmei Qian, Hualong Li, Wei Tian, Hang Yu, Yingtao Zhang, Ming Guan, Zhongwei Ma
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Buildings
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Online Access:https://www.mdpi.com/2075-5309/15/9/1404
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author Yongmei Qian
Hualong Li
Wei Tian
Hang Yu
Yingtao Zhang
Ming Guan
Zhongwei Ma
author_facet Yongmei Qian
Hualong Li
Wei Tian
Hang Yu
Yingtao Zhang
Ming Guan
Zhongwei Ma
author_sort Yongmei Qian
collection DOAJ
description The NT-CEP pile is an innovative type of pile that builds upon the conventional concrete straight-hole cast-in-place pile. It primarily consists of two components: the main pile and the bearing plate. The key factors influencing its load-bearing capacity include the pile diameter, the cantilever dimensions of the bearing plate, and the slope of the bearing plate’s foot, among others. The pile spacing significantly influences the bearing capacity of NT-CEP pile group foundations. The overall bearing capacity of an NT-CEP pile group foundation is not merely the sum of the ultimate bearing capacities of individual piles; rather, it results from the interactions among the pile bodies, the cap, and the foundation soil. Advancing the design theory of NT-CEP pile groups and enhancing their practical applications in engineering requires an in-depth investigation of how different pile spacings influence the load-bearing performance of pile group foundations. This objective can be achieved by exploring the soil damage mechanisms around side, corner, and central piles. This exploration helps in clarifying the influence of pile spacing on the load-bearing performance. Based on research findings regarding the bearing capacity of single and double pile foundations, this paper utilizes ANSYS finite element simulation analysis to model six-pile and nine-pile groups. Because these arrangements are universally adopted in engineering practice, they are capable of accounting for the pile group effect under various pile spacings and row configurations. The nine-pile group comprises corner piles, side piles, and a center pile, enabling a comprehensive analysis of stress variations among piles at different positions. As six-pile and nine-pile groups represent common pile configurations, studying these two types can provide valuable insights and direct references for optimizing pile foundation design. The study systematically investigates the influence of varying piles spacings on the bearing capacity of NT-CEP pile group foundations. It concludes that, as pile spacing decreases, The displacement of the top of this pile increases. thereby enhancing the group piles effects. Conversely, increasing the spacing between piles represents an effective strategy for elevating the compressive capacity of the NT-CEP pile-group foundation. Larger spacing also increases the vertical load-bearing capacity of the central piles, enhances the lateral friction resistance of corner piles, and heightens the load-sharing proportion between the bearing plate and the pile end. Furthermore, increasing pile spacing raises the ratio of load sharing by the foundation soil for both the CEP nine-pile foundation and the CEP six-pile foundation. The reliability of the simulation study has been verified by a visualization small scale model test of a half cut pile.
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spelling doaj-art-bbb351e3fff54d878f1cb4edb76283ca2025-08-20T02:58:44ZengMDPI AGBuildings2075-53092025-04-01159140410.3390/buildings15091404Effect of Pile Spacing on Load Bearing Performance of NT-CEP Pile Group FoundationYongmei Qian0Hualong Li1Wei Tian2Hang Yu3Yingtao Zhang4Ming Guan5Zhongwei Ma6College of Civil Engineering, Jilin Jianzhu University, Changchun 130118, ChinaCollege of Civil Engineering, Jilin Jianzhu University, Changchun 130118, ChinaSchool of Transportation Science and Engineering, Jilin Jianzhu University, Changchun 130118, ChinaYanji Branch of Jilin Expressway Group Co., Ltd., Yanji 133000, ChinaChina Construction Fifth Engineering Bureau Co., Ltd., Changsha 410004, ChinaChina Construction Fifth Engineering Bureau Co., Ltd., Changsha 410004, ChinaChina Construction Fifth Engineering Bureau Co., Ltd., Changsha 410004, ChinaThe NT-CEP pile is an innovative type of pile that builds upon the conventional concrete straight-hole cast-in-place pile. It primarily consists of two components: the main pile and the bearing plate. The key factors influencing its load-bearing capacity include the pile diameter, the cantilever dimensions of the bearing plate, and the slope of the bearing plate’s foot, among others. The pile spacing significantly influences the bearing capacity of NT-CEP pile group foundations. The overall bearing capacity of an NT-CEP pile group foundation is not merely the sum of the ultimate bearing capacities of individual piles; rather, it results from the interactions among the pile bodies, the cap, and the foundation soil. Advancing the design theory of NT-CEP pile groups and enhancing their practical applications in engineering requires an in-depth investigation of how different pile spacings influence the load-bearing performance of pile group foundations. This objective can be achieved by exploring the soil damage mechanisms around side, corner, and central piles. This exploration helps in clarifying the influence of pile spacing on the load-bearing performance. Based on research findings regarding the bearing capacity of single and double pile foundations, this paper utilizes ANSYS finite element simulation analysis to model six-pile and nine-pile groups. Because these arrangements are universally adopted in engineering practice, they are capable of accounting for the pile group effect under various pile spacings and row configurations. The nine-pile group comprises corner piles, side piles, and a center pile, enabling a comprehensive analysis of stress variations among piles at different positions. As six-pile and nine-pile groups represent common pile configurations, studying these two types can provide valuable insights and direct references for optimizing pile foundation design. The study systematically investigates the influence of varying piles spacings on the bearing capacity of NT-CEP pile group foundations. It concludes that, as pile spacing decreases, The displacement of the top of this pile increases. thereby enhancing the group piles effects. Conversely, increasing the spacing between piles represents an effective strategy for elevating the compressive capacity of the NT-CEP pile-group foundation. Larger spacing also increases the vertical load-bearing capacity of the central piles, enhances the lateral friction resistance of corner piles, and heightens the load-sharing proportion between the bearing plate and the pile end. Furthermore, increasing pile spacing raises the ratio of load sharing by the foundation soil for both the CEP nine-pile foundation and the CEP six-pile foundation. The reliability of the simulation study has been verified by a visualization small scale model test of a half cut pile.https://www.mdpi.com/2075-5309/15/9/1404pile spacingnew concrete plate expanding pilepile groupcompressive load resistance
spellingShingle Yongmei Qian
Hualong Li
Wei Tian
Hang Yu
Yingtao Zhang
Ming Guan
Zhongwei Ma
Effect of Pile Spacing on Load Bearing Performance of NT-CEP Pile Group Foundation
Buildings
pile spacing
new concrete plate expanding pile
pile group
compressive load resistance
title Effect of Pile Spacing on Load Bearing Performance of NT-CEP Pile Group Foundation
title_full Effect of Pile Spacing on Load Bearing Performance of NT-CEP Pile Group Foundation
title_fullStr Effect of Pile Spacing on Load Bearing Performance of NT-CEP Pile Group Foundation
title_full_unstemmed Effect of Pile Spacing on Load Bearing Performance of NT-CEP Pile Group Foundation
title_short Effect of Pile Spacing on Load Bearing Performance of NT-CEP Pile Group Foundation
title_sort effect of pile spacing on load bearing performance of nt cep pile group foundation
topic pile spacing
new concrete plate expanding pile
pile group
compressive load resistance
url https://www.mdpi.com/2075-5309/15/9/1404
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