Deformation Characteristics and Base Stability of a Circular Deep Foundation Pit with High-Pressure Jet Grouting Reinforcement

This study investigates the deformation characteristics and base stability of a circular diaphragm wall support system (external diameter: 90 m, wall thickness: 1.5 m) with pit bottom reinforcement for the South Anchorage deep foundation pit of the Zhangjinggao Yangtze River Bridge, which uses layer...

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Main Authors: Xiaoliang Zhu, Wenqing Zhao, Junchen Zhao, Guoliang Dai, Ruizhe Jin, Zhiwei Chen, Wenbo Zhu
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/12/6825
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author Xiaoliang Zhu
Wenqing Zhao
Junchen Zhao
Guoliang Dai
Ruizhe Jin
Zhiwei Chen
Wenbo Zhu
author_facet Xiaoliang Zhu
Wenqing Zhao
Junchen Zhao
Guoliang Dai
Ruizhe Jin
Zhiwei Chen
Wenbo Zhu
author_sort Xiaoliang Zhu
collection DOAJ
description This study investigates the deformation characteristics and base stability of a circular diaphragm wall support system (external diameter: 90 m, wall thickness: 1.5 m) with pit bottom reinforcement for the South Anchorage deep foundation pit of the Zhangjinggao Yangtze River Bridge, which uses layered and partitioned top-down excavation combined with lining construction. Through field monitoring (deep horizontal displacement of the diaphragm wall, vertical displacement at the wall top, and earth pressure) and numerical simulations (PLAXIS Strength Reduction Method), we systematically analyzed the deformation evolution and failure mechanisms during construction. The results indicate the following: (1) Under the synergistic effect of the circular diaphragm wall, lining, and pit bottom reinforcement, the maximum horizontal displacement at the wall top was less than 30 mm and the vertical displacement was 0.04%H, both significantly below code-specified thresholds, verifying the effectiveness of the support system and pit bottom reinforcement. (2) Earth pressure exhibited a “decrease-then-increase” trend during the excavation proceeds. High-pressure jet grouting pile reinforcement at the pit base significantly enhanced basal constraints, leading to earth pressure below the Rankine active limit during intermediate stages and converging toward theoretical values as deformation progressed. (3) Without reinforcement, hydraulic uplift failure manifested as sand layer suspension and soil shear. After reinforcement, failure modes shifted to basal uplift and wall-external soil sliding, demonstrating that high-pressure jet grouting pile reinforcement had positive contribution basal heave stability by improving soil shear strength. (4) Improved stability verification methods for anti-heave and anti-hydraulic-uplift were proposed, incorporating soil shear strength contributions to overcome the underestimation of reinforcement effects in traditional pressure equilibrium and Terzaghi bearing capacity models. This study provides theoretical and practical references for similar deep foundation pit projects and offers systematic solutions for the safety design and deformation characteristics of circular diaphragm walls with pit bottom reinforcement.
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issn 2076-3417
language English
publishDate 2025-06-01
publisher MDPI AG
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spelling doaj-art-3fd172e4e6c342aeb140c561fe5f4f5f2025-08-20T02:24:30ZengMDPI AGApplied Sciences2076-34172025-06-011512682510.3390/app15126825Deformation Characteristics and Base Stability of a Circular Deep Foundation Pit with High-Pressure Jet Grouting ReinforcementXiaoliang Zhu0Wenqing Zhao1Junchen Zhao2Guoliang Dai3Ruizhe Jin4Zhiwei Chen5Wenbo Zhu6Road & Bridge International Co., Ltd., Beijing 100010, ChinaSchool of Civil Engineering, Southeast University, Nanjing 211189, ChinaRoad & Bridge International Co., Ltd., Beijing 100010, ChinaSchool of Civil Engineering, Southeast University, Nanjing 211189, ChinaSchool of Civil Engineering, Southeast University, Nanjing 211189, ChinaSchool of Civil Engineering, Southeast University, Nanjing 211189, ChinaSchool of Civil Engineering, Southeast University, Nanjing 211189, ChinaThis study investigates the deformation characteristics and base stability of a circular diaphragm wall support system (external diameter: 90 m, wall thickness: 1.5 m) with pit bottom reinforcement for the South Anchorage deep foundation pit of the Zhangjinggao Yangtze River Bridge, which uses layered and partitioned top-down excavation combined with lining construction. Through field monitoring (deep horizontal displacement of the diaphragm wall, vertical displacement at the wall top, and earth pressure) and numerical simulations (PLAXIS Strength Reduction Method), we systematically analyzed the deformation evolution and failure mechanisms during construction. The results indicate the following: (1) Under the synergistic effect of the circular diaphragm wall, lining, and pit bottom reinforcement, the maximum horizontal displacement at the wall top was less than 30 mm and the vertical displacement was 0.04%H, both significantly below code-specified thresholds, verifying the effectiveness of the support system and pit bottom reinforcement. (2) Earth pressure exhibited a “decrease-then-increase” trend during the excavation proceeds. High-pressure jet grouting pile reinforcement at the pit base significantly enhanced basal constraints, leading to earth pressure below the Rankine active limit during intermediate stages and converging toward theoretical values as deformation progressed. (3) Without reinforcement, hydraulic uplift failure manifested as sand layer suspension and soil shear. After reinforcement, failure modes shifted to basal uplift and wall-external soil sliding, demonstrating that high-pressure jet grouting pile reinforcement had positive contribution basal heave stability by improving soil shear strength. (4) Improved stability verification methods for anti-heave and anti-hydraulic-uplift were proposed, incorporating soil shear strength contributions to overcome the underestimation of reinforcement effects in traditional pressure equilibrium and Terzaghi bearing capacity models. This study provides theoretical and practical references for similar deep foundation pit projects and offers systematic solutions for the safety design and deformation characteristics of circular diaphragm walls with pit bottom reinforcement.https://www.mdpi.com/2076-3417/15/12/6825circular diaphragm walldeep foundation pitdeformation characteristicshigh-pressure jet grouting pilesanti-heave stabilityanti-hydraulic-uplift stability
spellingShingle Xiaoliang Zhu
Wenqing Zhao
Junchen Zhao
Guoliang Dai
Ruizhe Jin
Zhiwei Chen
Wenbo Zhu
Deformation Characteristics and Base Stability of a Circular Deep Foundation Pit with High-Pressure Jet Grouting Reinforcement
Applied Sciences
circular diaphragm wall
deep foundation pit
deformation characteristics
high-pressure jet grouting piles
anti-heave stability
anti-hydraulic-uplift stability
title Deformation Characteristics and Base Stability of a Circular Deep Foundation Pit with High-Pressure Jet Grouting Reinforcement
title_full Deformation Characteristics and Base Stability of a Circular Deep Foundation Pit with High-Pressure Jet Grouting Reinforcement
title_fullStr Deformation Characteristics and Base Stability of a Circular Deep Foundation Pit with High-Pressure Jet Grouting Reinforcement
title_full_unstemmed Deformation Characteristics and Base Stability of a Circular Deep Foundation Pit with High-Pressure Jet Grouting Reinforcement
title_short Deformation Characteristics and Base Stability of a Circular Deep Foundation Pit with High-Pressure Jet Grouting Reinforcement
title_sort deformation characteristics and base stability of a circular deep foundation pit with high pressure jet grouting reinforcement
topic circular diaphragm wall
deep foundation pit
deformation characteristics
high-pressure jet grouting piles
anti-heave stability
anti-hydraulic-uplift stability
url https://www.mdpi.com/2076-3417/15/12/6825
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