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Article

Numerical Analysis of Diaphragm Wall Deformation and Surface Settlement Caused by Dewatering and Excavation at Center and End Positions in a Subway Foundation Pit

by
Kaifang Yang
1,2,
Mingdong Jiang
1,2,*,
Minliang Chi
2,* and
Guohui Feng
1,2
1
College of Engineering, Hangzhou City University, Hangzhou 310015, China
2
College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
*
Authors to whom correspondence should be addressed.
Buildings 2025, 15(15), 2796; https://doi.org/10.3390/buildings15152796
Submission received: 27 June 2025 / Revised: 17 July 2025 / Accepted: 6 August 2025 / Published: 7 August 2025
(This article belongs to the Special Issue Research on Rock Mechanics and Rock Engineering, Geotechnical Engineering and Mining Sciences in Construction—2nd Edition)
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Abstract

Metro foundation pits are important components of urban infrastructure projects. Dewatering and excavation are essential stages in foundation pit construction; however, this process can significantly induce groundwater drawdown, as well as diaphragm wall deformation and surface settlement. Based on a subway station foundation pit project, in this study, we employ three-dimensional numerical software to simulate the process of dewatering and excavation. A refined model is used to investigate groundwater seepage, the deformation of the retaining structure, and surface settlement under spatial effects. The finite element model accounts for stratified excavation and applied prestress conditions for the support system within the foundation pit. Its accuracy is validated through a comparison and analysis with measured data from the actual foundation pit. The results indicate that foundation pit excavation leads to significant groundwater drawdown around the pit and the formation of a characteristic “funnel-shaped” drawdown curve. Moreover, extending the diaphragm wall length contributes to maintaining a higher external groundwater level surrounding the foundation pit. The horizontal displacement of the diaphragm wall increases progressively during dewatering and excavation, and the bending moment of the diaphragm wall exhibits a trend consistent with its horizontal displacement. Surface settlement decreases as the length of the diaphragm wall increases.

1. Introduction

The rapid urbanization of densely populated areas in recent years has accelerated the growth of long and narrow underground infrastructure, including subway stations [1,2,3,4]. During the construction of foundation pits for such infrastructure, it is critical to address risks associated with soil unloading while thoroughly assessing the environmental effects of groundwater extraction [5,6,7,8]. This is particularly important in regions with high rainfall and abundant groundwater, where dewatering is essential to ensure a dry and stable working environment while constructing deep subway foundation pits [9,10,11].
Currently, the primary methods used for investigating foundation pit deformation and surface settlement include field measurement data analysis [9,12,13,14], physical model testing [15,16,17,18], and numerical simulation [8,19,20,21,22,23]. Among these methods, advancing computer technology has made numerical modeling increasingly prevalent. The excavation and dewatering of foundation pits are the two primary factors contributing to the deformation of retaining structures and surface settlement. Li et al. [10] conducted a case study of a subway station foundation pit, investigating the excavation–dewatering interaction and proposing an engineering experience-based method for surface settlement evaluation. Artificial recharge wells provide an effective solution for mitigating surface settlement induced through foundation pit dewatering. Zeng et al. [20] contributed to this field by developing a combined recharge well method to control surface settlement. Shi et al. [24] developed a three-dimensional seepage–stress coupled numerical model to investigate deformation processes in deep foundation pits within water-rich strata. Xu et al. [25] identified seepage control as a critical consideration in deep foundation pit engineering. Their study examined a case in which dewatering-induced seepage compromised both the retaining structure and the surrounding environment, underscoring the substantial risks posed by inadequate groundwater management. Yuan et al. [26] employed MIDAS/GTS software to numerically simulate a deep foundation pit in water-rich strata, based on geological exploration reports and design documents, and analyzed seepage-induced effects on retaining structure deformation during pit excavation. Wu et al. [27] employed the finite difference method to investigate the water-blocking effect of the foundation pit through numerically simulating pumping processes. Their results demonstrated that groundwater-level depression correlates with confined aquifer depth.
These studies systematically evaluated three critical phenomena during excavation and dewatering sequences: (1) retaining wall lateral displacement, (2) ground surface settlement, and (3) groundwater seepage. Previous studies have failed to account for several critical factors: (1) the excavation sequence in foundation pit dewatering, (2) the positioning of various support structures, and (3) the construction conditions of retaining elements (e.g., prestress conditions). These omissions prevent the establishment of a refined three-dimensional numerical model. Consequently, it remains impossible to investigate the deformation behavior of retaining structures or analyze the three-dimensional characteristics of surface settlement induced through dewatering and excavation.
This study developed a comprehensive three-dimensional finite element model based on the deep foundation pit project of Nanchang Metro, utilizing advanced numerical software to simulate the complex geotechnical conditions. This study also investigated the three-dimensional evolution of seepage fields induced by combined excavation and dewatering activities, analyzing the deformation of the diaphragm wall and surface settlement at various locations induced through dewatering and excavation under spatial effects. The design of foundation pits must account for the deformation of the diaphragm wall and surface settlement resulting from dewatering and excavation under spatial effects.

2. Establishment of a Refined 3D Numerical Model (Holland)

The numerical simulations in this study were conducted using PLAXIS 3D V22, a finite element analysis software. Compared to other numerical software, PLAXIS 3D offers several advantages, including an intuitive user interface, a streamlined modeling process, and visualization results. PLAXIS offers comprehensive constitutive modeling capabilities, enabling the sophisticated simulation of geotechnical structures and construction processes under complex loading and boundary conditions. The software further facilitates coupled hydro-mechanical analysis, including both steady-state and transient seepage conditions, as well as complex fluid–solid interaction phenomena. These advanced capabilities enable the precise simulation of soil–structure interaction problems in practical engineering applications. This finite element software is widely used by researchers and geotechnical engineers due to its reliability and strength simulation capabilities.

2.1. Model Dimensions and Boundary Conditions

As shown in Figure 1, the numerical model was developed at prototype scale (1:1) based on an actual deep excavation project from Nanchang Metro Line 4 in Jiangxi Province, accurately replicating the geometric dimensions and boundary conditions of the construction site. The station features a two-level underground island platform configuration, utilizing a three-span double-column structural system for optimal load distribution and spatial efficiency. The metro foundation pit is 238.0 m in length, with a standard section width of 22.7 m and an excavation depth of approximately 16.0 m. At both ends of the excavation, the width extends to 24.0 m, with an excavation depth of approximately 18.0 m, as illustrated in Figure 2. These diaphragm walls, constructed from reinforced concrete, are 0.8 m thick. The internal support system consists of one reinforced concrete support and two steel pipe supports. The dimensions of the first support cross-section are 0.8 m × 1 m, with a spacing of 9 m. The steel pipe supports have a diameter of 0.609 m and a wall thickness of 16 mm, with horizontal spacing of 3 m. A cross-sectional view of the foundation pit is shown in Figure 3.
Considering the long and narrow characteristics of the metro foundation pit and the dewatering influence radius, the numerical model was extended to six times the excavation depth in both the longitudinal and widthwise directions of the pit. In the excavation depth, the model was extended to 3 times the excavation depth [28]. Thus, the boundary dimensions of the 3D finite element model were as follows: the X-horizontal direction length was 400 m, the Y-horizontal direction width was 200 m, and the Z-vertical direction depth was 60 m.
The mesh used in the PLAXIS 3D finite element model consisted of 10-node tetrahedral elements. The entire model comprised approximately 100,000 elements and 180,000 nodes, as illustrated in Figure 4. The boundary conditions for the numerical model were as follows: The bottom surface was fully constrained in all directions (X, Y, and Z), constraining any displacement. The four vertical surfaces were constrained only in their respective normal directions, allowing movement parallel to the surfaces. The top surface was treated as a free surface with no constraints, permitting full deformation in response to applied loads.

2.2. Selection of Soil and Retaining Structure Parameters

In this study, the hardening soil model with small-strain stiffness (HSS) was adopted for the 3D finite element soil simulation. Geotechnical engineering practice suggests that soil within a foundation pit excavation generally remains in a small-strain state prior to failure. The HSS model distinguishes between loading and unloading stiffness, making it theoretically more aligned with the actual stress–strain behavior observed during foundation pit excavation. Based on relevant studies [29,30], the empirical relationships between the model parameters are summarized as Eoedref/E50ref/Eurref = 1:0.8–2:3–8, as shown in Table 1.
In the finite element model of the metro foundation pit, diaphragm walls were modeled using plate elements [31,32]. The implementation of interface elements was used to simulate the groundwater-blocking behavior of the diaphragm walls. In the model, reinforced concrete supports were modeled as beam elements, while steel supports were simulated using anchor elements capable of applying the prestressing force. According to the foundation pit retaining structure design, a prestressing force of 700 kN was applied to the supports located at the end, while a prestressing force of 400 kN was applied to the steel supports at all other locations.
The column piles were modeled as embedded beam elements, with geometric properties (diameter, length, spacing) and spatial positioning strictly conforming to the foundation pit cross-sectional design drawings. The specific parameters are provided in Table 2.

2.3. Excavation Conditions

As documented in Table 3 and illustrated in Figure 5, the refined 3D finite element model accurately performed a sequential simulation of the actual construction process, employing a layer-by-layer soil excavation methodology that mirrored the staged implementation observed on site. Dewatering and excavation were conducted concurrently with the installation of support structures [28].
The soil within the foundation pit was segmented into seven longitudinal sections, labeled A to G, and stratified into six layers by depth. This zoning facilitated a step-by-step layered excavation process. A partial view of the excavation condition model is presented in Figure 6.

3. Validation of the Numerical Simulation

Figure 7 presents a comparison of the diaphragm wall horizontal displacements between field-measured data and numerical calculation data, focusing on both the ends and center sections of the foundation pit. As illustrated in Figure 7, the horizontal displacement calculated using the numerical model aligns well with the onsite measured data, with both exhibiting a bulge distribution pattern. The displacement near the top of the diaphragm wall is relatively minimal, suggesting effective restraint from the top supporting structures. The horizontal displacement gradually increases with depth, reaching maximum displacement near the bottom of the foundation pit. Below this, the displacement decreases and eventually approaches zero.
The maximum horizontal displacements, both from the numerical model and onsite measurement, occur near the bottom of the foundation pit. At the center of the pit, the model predicts a maximum displacement of 16.5 mm, whereas the measured data shows a maximum displacement of 20.3 mm, resulting in a difference of 18.8%. At the end shaft, the model predicts a maximum displacement of 11.8 mm, whereas the measured data shows a maximum displacement of 13.8 mm, resulting in a difference of 14.8%. These findings confirm the reliability and accuracy of the finite element model.
As a result, the calculated displacements at both the end shaft and the center of the foundation pit are slightly greater than the measured values. The analysis reveals two primary causes: 1. Existing reinforcement measures in foundation pit engineering were not accounted for in the numerical model, and the numerical model simplified and homogenized the soil layers, resulting in lower measured values compared to calculated ones. 2. The computational method failed to incorporate multiphysics interactions (e.g., seepage–stress coupling), leading to the overestimation of pore water pressure through single-field simulations.

4. Analysis of Numerical Model Results

As shown in Table 4, this study investigated the deformation of the retaining structure and surface settlement during dewatering and excavation under three-dimensional conditions. To estimate the effect of the diaphragm wall length on foundation pit deformation, four different lengths of diaphragm wall were analyzed. This study investigated the deformation patterns during dewatering and excavation, with an initial groundwater table positioned at a depth of −4.0 m.

4.1. Groundwater Drawdown and Seepage Field

Figure 8 and Figure 9 illustrate the groundwater seepage field and the extent of the affected area around the foundation pit resulting from dewatering and excavation under different diaphragm wall lengths.
As illustrated in Figure 8, foundation pit dewatering causes groundwater drawdown outside the pit and a new water table to form. The groundwater drops significantly near the foundation pit, developing a characteristic “funnel-shaped” drawdown curve. Foundation pit dewatering can be effectively simulated by pumping water. As the length of the diaphragm wall increases, it slows the rate of groundwater drawdown near the foundation pit and reduces the affected area.
As illustrated in Figure 8, dewatering and excavation generate a seepage field around the pit, drawing groundwater from distant areas to replenish the adjacent region. Groundwater flows into the foundation pit through two distinct pathways: bypass flow along the diaphragm wall and horizontal flow through the surrounding soil. Increasing the length of the diaphragm wall extends the seepage path of the groundwater, reducing the influence of dewatering on the surrounding seepage field.
As illustrated in Figure 9, the foundation pit design incorporated a 26-m-long diaphragm wall that penetrated into the low-permeability, strongly weathered rock layer, effectively controlling the groundwater levels. Consequently, groundwater drawdown caused by dewatering was substantially reduced, significantly mitigating the environmental impact of the foundation pit’s excavation.

4.2. Horizontal Displacement of the Diaphragm Wall

Figure 10 illustrates the deep horizontal displacement of the diaphragm wall under different dewatering and excavation depths. Horizontal displacements of the diaphragm wall increase proportionally with the excavation depth, reaching maximum values at a wall length of 26 m. The extended diaphragm wall increases the groundwater level outside the pit, thereby amplifying both pore water pressures and effective earth pressures acting on the diaphragm wall.
The maximum horizontal displacement of the diaphragm walls at the pit center and end was extracted from Figure 10 and presented in Table 5. As shown in Table 5, when the excavation depth is relatively shallow, the difference in maximum horizontal displacement between the two locations is small. However, the diaphragm wall at the end exhibits a larger displacement than the diaphragm wall at the pit center. For example, at an excavation depth of 11.5 m, when the diaphragm wall lengths are 20 m, 22 m, 24 m, and 26 m, the difference rates in horizontal displacement between the center and end are −6.3%, −3.2%, −1.4%, and 0.6%, respectively. As the excavation depth increases, the difference in horizontal displacement between the two locations becomes significantly more pronounced. For example, at an excavation depth of 16/18 m, the difference rates in horizontal displacement between the pit center and end are 2.0%, 16.9%, 25.1%, and 32.4% for diaphragm wall lengths of 20 m, 22 m, 24 m, and 26 m, respectively. The results demonstrate that longer diaphragm walls lead to greater displacement differences, with the maximum variation reaching 30.4% between the shortest and longest walls.
The maximum horizontal displacement of the diaphragm wall consistently occurs near the foundation pit. This behavior is influenced by the differing prestressing forces applied to the second and third steel supports at the center and end shaft. Specifically, the end shaft is reinforced with 700 kN of prestressing force, compared to 400 kN at the pit center. When the excavation depth is less than 14 m, the maximum horizontal displacement at the pit center is located above the pit bottom, while it occurs below the pit bottom at the end shaft. However, as the excavation depth reaches the pit bottom, the maximum horizontal displacement at both the pit center and end shaft shifts to approximately 0.5 to 1.0 m above the pit bottom.

4.3. Bending Moment of the Diaphragm Wall

Figure 11 illustrates the bending moment of the diaphragm wall under different excavation depths, where positive values (+) indicate bending toward the inside of the pit and negative values (-) indicate bending toward the outside of the pit. The bending moment distribution closely corresponds to the horizontal displacement trends discussed in Section 4.2, demonstrating consistent structural behavior throughout excavation.
At the end of the foundation pit, the elevated groundwater level leads to increased water and soil loads. Furthermore, the corner effect—a stress concentration phenomenon occurring at pit corners—intensifies the bending moment at this location, resulting in a greater increase compared to other sections.
Whether at the pit center or the end shaft, a longer diaphragm wall results in a greater bending moment. Consequently, foundation pit designs must account for amplified bending moments at the end shaft. To address the additional stresses, the degree of reinforcement should be appropriately increased in these regions.

4.4. Surface Settlement Outside the Foundation Pit

Figure 12 illustrates the surface settlement around the foundation pit at different excavation depths, and excavation creates a distinct settlement trough on the ground surface. Notably, the maximum settlement does not occur directly at the top of the diaphragm wall but is located within a distance of approximately 0.5 to 1.0 times the excavation depth. Surface settlements decrease progressively with distance from the foundation pit, following a characteristic attenuation pattern.
When the diaphragm wall length is less than 22 m, surface settlement at the pit center is smaller than at the end shaft. However, when the diaphragm wall length exceeds 22 m, the settlement at the pit center exceeds that observed at the end shaft. For a diaphragm wall length of 26 m, the difference in settlement between the pit center and the end shaft increases from 0.104 mm to 4.89 mm as the excavation depth increases.
During dewatering and excavation, surface settlement outside the pit decreases as the diaphragm wall length increases. When the foundation pit is excavated to the bottom, the length of the diaphragm wall is increased significantly to reduce the surface settlement. In the design of a foundation pit, increasing the length minimizes the influence of the surrounding environment.

5. Conclusions

Based on a deep foundation pit of a subway in Nanchang, finite element software was used to establish a three-dimensional refined numerical model, with this study investigating the three-dimensional seepage field around the pit, the deformation of the diaphragm wall, and surface settlement caused by foundation pit dewatering and excavation. The following conclusions have been drawn:
(1)
A refined 3D numerical model for foundation pit dewatering and excavation was established using the finite element software PLAXIS. The numerical model successfully revealed the critical mechanisms underlying foundation pit deformation and support force distribution. The efficiency was compared to traditional empirical methods. The model incorporated staged excavation and prestressed support conditions. Its accuracy was validated through comparison with field-measured data, confirming its reliability for analyzing the behavior of foundation pit dewatering and excavation.
(2)
Foundation pit dewatering and excavation led to significant groundwater drawdown around the pit and the formation of a characteristic “funnel-shaped” drawdown curve. Increasing the length of the diaphragm wall effectively reduced the groundwater drawdown near the pit and constrained the zone of dewatering influence.
(3)
A longer diaphragm wall resulted in higher external groundwater levels, thereby increasing the horizontal displacement of the diaphragm wall during dewatering and excavation. When the excavation depth reached the pit bottom, the maximum horizontal displacement typically occurred 0.5 to 1.0 m above the pit bottom.
(4)
The bending moment distribution in the diaphragm wall aligned with its horizontal displacement pattern. As the length of the diaphragm wall increased, internal forces became more significant. Foundation pit design should account for these variations by enhancing structural reinforcement to ensure safety and stability.

Author Contributions

Conceptualization, K.Y. and M.J.; methodology, K.Y. and M.C.; software, K.Y., M.J. and M.C.; validation, K.Y. and G.F.; formal analysis, K.Y., M.C. and G.F.; investigation, M.C. and G.F.; data curation, K.Y. and M.J.; writing—original draft preparation, K.Y., M.J. and M.C.; writing—review and editing, M.C. and G.F. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Natural Science Foundation of China (grant numbers 52408395 and 52408448) and the Special Financial Grant from the China Postdoctoral Science Foundation (grant number 2025T180880).

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors on request.

Acknowledgments

We deeply appreciate the helpful and efficient work of the editors and reviewers.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Nanchang Metro Line 4 and site photograph.
Figure 1. Nanchang Metro Line 4 and site photograph.
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Figure 2. A schematic diagram of the foundation pit retaining structure.
Figure 2. A schematic diagram of the foundation pit retaining structure.
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Figure 3. A cross-section of a foundation pit with a retaining structure.
Figure 3. A cross-section of a foundation pit with a retaining structure.
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Figure 4. Mesh generation unit drawing of subway foundation pit.
Figure 4. Mesh generation unit drawing of subway foundation pit.
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Figure 5. Vertical section direction unloading of the foundation pit.
Figure 5. Vertical section direction unloading of the foundation pit.
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Figure 6. A numerical model of foundation pit soil excavation and the installation of support structures. (a) Stage 5. (b) Stage 10.
Figure 6. A numerical model of foundation pit soil excavation and the installation of support structures. (a) Stage 5. (b) Stage 10.
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Figure 7. The horizontal displacement of the diaphragm wall.
Figure 7. The horizontal displacement of the diaphragm wall.
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Figure 8. Groundwater seepage field and groundwater for different diaphragm wall lengths. (a) The length is 20 m. (b) The length is 22 m. (c) The length is 24 m. (d) The length is 26 m.
Figure 8. Groundwater seepage field and groundwater for different diaphragm wall lengths. (a) The length is 20 m. (b) The length is 22 m. (c) The length is 24 m. (d) The length is 26 m.
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Figure 9. The influence range of groundwater under different diaphragm wall lengths. (a) The length is 20 m. (b) The length is 22 m. (c) The length is 24 m. (d) The length is 26 m.
Figure 9. The influence range of groundwater under different diaphragm wall lengths. (a) The length is 20 m. (b) The length is 22 m. (c) The length is 24 m. (d) The length is 26 m.
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Figure 10. The horizontal displacement and excavation depth in the foundation pit. (a) Excavating to −5.0 m. (b) Excavating to −8.0 m. (c) Excavating to −11.5 m. (d) Excavating to −14.0 m. (e) Excavating to the bottom of pit.
Figure 10. The horizontal displacement and excavation depth in the foundation pit. (a) Excavating to −5.0 m. (b) Excavating to −8.0 m. (c) Excavating to −11.5 m. (d) Excavating to −14.0 m. (e) Excavating to the bottom of pit.
Buildings 15 02796 g010
Buildings 15 02796 g011
Figure 11. The bending moment and excavation depth in the foundation pit. (a) Excavating to −5.0 m. (b) Excavating to −8.0 m. (c) Excavating to −11.5 m. (d) Excavating to −14.0 m. (e) Excavating to the bottom of the pit.
Figure 11. The bending moment and excavation depth in the foundation pit. (a) Excavating to −5.0 m. (b) Excavating to −8.0 m. (c) Excavating to −11.5 m. (d) Excavating to −14.0 m. (e) Excavating to the bottom of the pit.
Buildings 15 02796 g011
Buildings 15 02796 g012
Figure 12. The surface settlement and excavation depth in the foundation pit. (a) Excavating to −5.0 m. (b) Excavating to −8.0 m. (c) Excavating to −11.5 m. (d) Excavating to −14.0 m. (e) Excavating to the bottom of the pit.
Figure 12. The surface settlement and excavation depth in the foundation pit. (a) Excavating to −5.0 m. (b) Excavating to −8.0 m. (c) Excavating to −11.5 m. (d) Excavating to −14.0 m. (e) Excavating to the bottom of the pit.
Buildings 15 02796 g012
Table 1. The physical and mechanical parameters of soils.
Table 1. The physical and mechanical parameters of soils.
Soil StratumSoil Numberγ/(kN/m3)E50ref
/(kN/m2)		Eoedref
/(kN/m2)		Eurref
/(kN/m2)		c′
/kPa		φ′
/(°)		νG0ref
/(kN/m2)		K
/(m/d)
Fill①18.510,000800030008250.236,0005
Silty clay③-118.86000600030,0009.326.10.240,0000.004
Fine sand③-219.613,20011,00033,0006310.290,00015
Medium sand③-319.825,00025,00075,000730.70.2150,00040
Rounded gravel③-620.535,00035,000105,0002340.2210,000120
Weathered rock⑤-1-220.2-------1
Note: In the table, γ is the unit weight of the soil, c′ is the effective cohesion, φ′ is the effective friction angle, E50ref is the triaxial loading Young’s modulus at 50% of shear strength, Eoedref is the oedometric loading modulus, Eurref is the unloading–reloading Young modulus, m is the power function parameter, Pref is the reference pressure, and G0ref is the reference shear stiffness.
Table 2. The parameters of the retaining structure.
Table 2. The parameters of the retaining structure.
Retaining StructureUnit ElementE/(kN/m2)νEA/(kN/m2)Prestressing/(kN)Location/m
Diaphragm wallPlate 35 × 1060.2---
Reinforced concrete supportBeam30 × 1060.2--−1.5
Steel supportAnchor--7.5 × 106700, 400−7.0, −11.0
Column-pileEmbedded beam30 × 106----
Where E is the elastic modulus, A is the cross-sectional area, and ν is Poisson’s ratio.
Table 3. The key construction stages.
Table 3. The key construction stages.
Work ConditionConstruction ActivitiesWork ConditionConstruction Activities
Initial stageGenerating the initial ground stress and activating the underground diaphragm wall and column piles.Stage 8Excavating the soil in zones A5, C4, E3, and G2 and setting up supports.
Stage 1Excavating the soil in zone A1 and setting up supports.Stage 9Excavating the soil in zones B5, D4, and F3 and setting up supports.
Stage 2Excavating the soil in zones A2, B1, and C1 and setting up supports.Stage 10Excavating the soil in zones A6, C5, E4, and G3 and setting up supports.
Stage 3Excavating the soil in zones B2 and D1, and setting up supports.Stage 11Excavating the soil in zones B6, D5, and F4 and setting up supports.
Stage 4Excavating the soil in zones A3, C2, and E1 and setting up supports.Stage 12Excavating the soil in zones C6, E5, and G4 and setting up supports.
Stage 5Excavating the soil in zones B3, D2, and F1 and setting up supports.Stage 13Excavating the soil in zones D6 and F5 and setting up supports.
Stage 6Excavating the soil in zones A4, C3, E2, and G1 and setting up supports.Stage 14Excavating the soil in zones E6 and G5 and setting up supports.
Stage 7Excavating the soil in zones B4, D3, and F2 and setting up supports.Stage 15Excavating the soil in zones F6 and G6 and setting up supports.
Table 4. Numerical simulation conditions.
Table 4. Numerical simulation conditions.
ConditionDiaphragm Wall LengthExcavation Depth
Dewatering and Excavation20 m−1.5 m, −5.0 m, −8.0 m, −11.5 m
−14.0 m, −16.0/−18.0 m (Center/End)
22 m
24 m
26 m
Table 5. The difference rate of maximum horizontal displacement between the center and end.
Table 5. The difference rate of maximum horizontal displacement between the center and end.
Diaphragm Wall Length/mExcavation Depth/mMaximum Horizontal Displacement/mmThe Difference Rate Between Center and End
CenterEnd
20 m11.5
16/18		6.516.92−6.3%
15.0014.702.0%
22 m11.5
16/18		6.666.87−3.2%
15.0712.5116.9%
24 m11.5
16/18		7.037.13−1.4%
16.3412.2425.1%
26 m11.5
16/18		8.208.150.6%
20.4513.8332.4%
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Yang, K.; Jiang, M.; Chi, M.; Feng, G. Numerical Analysis of Diaphragm Wall Deformation and Surface Settlement Caused by Dewatering and Excavation at Center and End Positions in a Subway Foundation Pit. Buildings 2025, 15, 2796. https://doi.org/10.3390/buildings15152796

AMA Style

Yang K, Jiang M, Chi M, Feng G. Numerical Analysis of Diaphragm Wall Deformation and Surface Settlement Caused by Dewatering and Excavation at Center and End Positions in a Subway Foundation Pit. Buildings. 2025; 15(15):2796. https://doi.org/10.3390/buildings15152796

Chicago/Turabian Style

Yang, Kaifang, Mingdong Jiang, Minliang Chi, and Guohui Feng. 2025. "Numerical Analysis of Diaphragm Wall Deformation and Surface Settlement Caused by Dewatering and Excavation at Center and End Positions in a Subway Foundation Pit" Buildings 15, no. 15: 2796. https://doi.org/10.3390/buildings15152796

APA Style

Yang, K., Jiang, M., Chi, M., & Feng, G. (2025). Numerical Analysis of Diaphragm Wall Deformation and Surface Settlement Caused by Dewatering and Excavation at Center and End Positions in a Subway Foundation Pit. Buildings, 15(15), 2796. https://doi.org/10.3390/buildings15152796

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