Analysis of deformations and internal forces of diaphragm walls of a deep excavation by the open excavation method

Hong Nam Nguyen; Thi Minh Mai

doi:10.1117/12.3042078

26 September 2024 Analysis of deformations and internal forces of diaphragm walls of a deep excavation by the open excavation method

Hong Nam Nguyen, Thi Minh Mai

Author Affiliations +

Proceedings Volume 13279, Fifth International Conference on Green Energy, Environment, and Sustainable Development (GEESD 2024) ; 1327926 (2024) https://doi.org/10.1117/12.3042078
Event: Fifth International Conference on Green Energy, Environment, and Sustainable Development, 2024, Mianyang, China

Abstract

This study applies the finite element method to the analysis of deformation and internal force of the diaphragm wall of the excavation pit of a high-rise building during the phased construction by the open excavation method. The simulation results show that the horizontal displacements along the wall depth increase in value with the construction stages, reaching the maximum value at the final construction stage. Both deformation of the diaphragm wall and internal force of the diaphragm wall are controlled within allowable limits. As a result, the impact of the excavation on the adjacent works is small. Parameter studies show that in general, settlement of the ground surface of adjacent structures increases with increasing excavation depth, decreasing distance from the excavation to the adjacent structure, greater depth of initial groundwater level, and higher surface load. The finite element method demonstrates greater capability in simulating deep excavation problems in a more diverse and realistic manner compared to the elastic beam on elastic foundation method.

1. INTRODUCTION

Currently, the trend of constructing high-rise buildings and underground traffic works in big cities in the country is becoming more and more urgent. Therefore, the investigation, design and construction of deep foundation pits of the above works is a concerning topic, especially for areas with bad geology, shallow groundwater levels, and high construction density.

When constructing a deep excavation by the open excavation method, if one does not pay attention to the safety measures to protect the excavation wall, it may cause construction problems, especially leading to failures for neighboring works such as subsidence, cracking, and even collapse of houses. The design and construction of deep excavations are posing many challenges to construction practice in our country.

In urban construction, especially in large cities, underground structures are crucial components of urban technical infrastructure. The general idea is to efficiently utilize underground space for various economic, social, cultural, environmental, and civil defense purposes.

In Vietnam, in recent years, there has been an increasing number of urban underground construction projects, encompassing various types such as basement levels in high-rise buildings, underground parking lots, urban underground roads, underpasses, pedestrian tunnels, underground drainage pipes, etc. These projects involve contractors or investors from various countries. The construction of these types of facilities according to current trends has led to the emergence of numerous deep excavation types. These construction activities invariably have adverse effects on the foundations of existing and operational structures.

Many new issues, sometimes not covered by existing standards, arise during the survey, design, construction, and operation of foundation and substructure projects, including geological and ecological environments. One such impact is the influence of deep excavations on the deformation of nearby foundation structures¹. To address these challenges effectively, designers and constructors need to implement protective measures to safeguard the excavation walls and employ technically and economically sound excavation techniques that ensure environmental safety and avoid detrimental effects on previously constructed neighboring structures, such as the servo steel struts^2,3.

Currently, numerous civil and industrial projects are being built alongside existing structures, such as Landmark 81, Keangnam Hanoi Landmark Tower, Vincom Landmark 81, Bitexco Financial Tower, Vietcombank Tower, Times City Tower, Hanoi Lotte Center, etc. Constructing high-rise buildings like these requires deep excavation, which inevitably leads to deformation of the nearby foundations and structures. This deformation is complex and poses numerous difficult challenges that must be addressed. For large-scale projects, if these issues are not effectively handled, unforeseen disasters could occur during construction.

This study aims to analyze the adverse factors affecting the deformation of neighboring structures’ foundations caused by deep excavation construction and propose appropriate foundation pit design solutions. In addition, this study aims to analyze the deformation and internal force of the diaphragm wall of the deep excavation of high-rise buildings caused by the construction of the phased open excavation method to evaluate the design and propose safety measures in the construction process.

2. SIMULATION OF THE DEEP EXCAVATION PROBLEM

The project of archives of scientific and technological documents and films, photos, and audio recordings was built at 34 Phan Ke Binh Street, Cong Vi Ward, Ba Dinh District, Hanoi City⁴. The project has a construction land area of 1,760 m² and a total construction floor area (including the basement) of 40,625.51 m². There are 19 floors and 3 basements. The building height is 72.3 m. The project is classified as Group A, grade 1.

The problem of analyzing the deformation of the ground and the retaining structure of the deep excavation during construction by the phased open excavation method was simulated by the finite element method. Analysis was performed according to the plane strain problem, using the software Plaxis, version 8.6, Netherlands⁵. The two cross sections selected for analysis are the North-South section (NS) and the East-West section (EW). The simulated North- South section consists of 1460 triangular elements (Figure 1). The simulated East-West section consists of 1607 triangular elements (Figure 2).

Figure 1.

North-south section.

Figure 2.

East-west section.

The foundation pit has a length of 30 m, a width of 62.6 m and a depth of 11.5 m. The distances from the excavation to the neighboring structures to the South, North, East, and West are 20 m, 6 m, 17 m and 11 m, respectively. The surface loads in the South; North; East; and West of the building are 80 kN/m²; (30 kN/m² and 25 kN/m²); 30 kN/m²; and (30 kN/m² and 40 kN/m²), respectively.

The bracing system (KING-POST) uses 2H300 shaped steel. The bracing has the following dimensions: B=300 mm, H=300 mm, t₁=10 mm, t₂=15 mm. The weight is 188 kg/m, area A=237 cm², E=2.10⁸ kN/m², EA=4.74×10⁶ kN. The elevations of bracing 1: -2.0 m, bracing 2: -5.3 m, bracing 3: -8.6 m. The average distances of the supports in the horizontal and vertical directions are 4.0 m and 3.3 m, respectively.

The diaphragm wall is a cast-in-place concrete, 1000 mm thick to stabilize the deep foundation pit during construction. The wall is made from barrette piles, rectangular cross-section, 2.8 m wide. The barrette sections are waterproof and connected with rubber gaskets and steel, working together through the top girder and the side girder placed close to the wall inside of the basement. The barrette wall is kept stable during construction by a steel truss system. Using the barrette wall as a boundary diaphragm wall for the 3 basements, both as a combined earth retaining wall barrier and to withstand the vertical loads transmitted by the above structures. The barrette wall uses durable concrete grade B25 (grade 300), ϕ32 steel of AIII with Rs= 365 MPa. The diaphragm wall thickness of 100 cm, depth of 35 m, E=2.57×10⁷ kN/m², EA=2.57×10⁷ kN/m, EI=2.14×10⁶ kNm²/m, w=14.1 kN/m/m, v=0.2. The diaphragm wall is simulated by the Plate element, plane strain problem.

Bored piles for the foundation use concrete grade C30. Steel ϕ<10 uses AI steel with Ra=2200 kg/cm³, barbed wire ϕ<10 uses AIII steel with Ra=3600 kg/cm³.

There are two types of bored piles with different diameters D=1.2 m (D1200) and 1.0 m (D1000). The average distance between bored piles is assumed to be 3.5 m. Pile top elevation: -12.5 m, pile tip elevation: -37 m. The bored pile is modeled as the Plate element. The model parameters of bored piles D1000 and D1200 are shown in Table 1.

Table 1.

Model parameters of bored piles.

Parameters	Unit	D1000	D1200
Cross-sectional area, A	m2	0.785	1.1304
Unit weight, w	kN/m/m	0.942	1.356
Moment of inertia, I	m4	0.049	0.102
EA	kN/m	5.774E+06	8.314E+06
EI	kNm2/m	3.609E+05	7.483E+05
v	-	0.2	0.2

The ground soil consists of 7 layers from top to down as follows⁶. Layer 1 is sand backfilling 1.7 m thick. Layer 2 is low plastic clay, 7.5 m thick, soft plastic. Layer 3 is low plastic clay, 10.6 m thick, liquid state. Layer 4 is low plastic clay, 3.9 m thick, semi-hard state. Layer 5 is medium-coarse, medium-grained sand, 13.1 m thick. Layer 6 is coarse sand mixed with gravel, very dense, 5.6 m thick. Layer 7 is gravel and sand with a thickness of 32.7 m. The soil is modeled as the Hardening -Soil model⁷ (see Table 2).

Table 2.

Hardening soil model parameters.

Soil layer	Unit	1	2	3	4	5	6	7
γ	kN/m3	16	18.2	16.6	19.8	16.5	17	18
γsat	kN/m3	20	18.3	16.9	20.1	21.5	22	23
c	kN/m2	1	29	20	33	1	1	1
ϕ	degree	28	7.2	4.817	16.233	33	39	40
ψ	degree	0	0	0	0	3	9	10
E50ref	MPa	10	6.6	1.1	12.7	30	35	50
Eurref	MPa	30	19.8	3.3	38.1	90	105	150
ν	-	0.2	0.2	0.2	0.2	0.2	0.2	0.2
m	-	0.5	0.5	0.5	0.5	0.5	0.5	0.5
k	m/day	0.864	0.0422	0.053	0.021	1.0	1.0	1.0

The groundwater level is located at an elevation of -4 m from the natural ground surface. During the construction process, the contractor proposes to use the drainage ditch system arranged inside the foundation pit to collect water into the mobile sumps, then use pumps with a capacity of 40 m³ to lower the groundwater level. Therefore, it can be assumed that the groundwater level is lowered at the elevation of -11.5 m when digging to the bottom of the foundation pit (elevation -11.5 m), from the natural ground (elevation 0.0).

The foundation pit can be excavated by the following stages⁴:

Preparation stage: First, the diaphragm wall is constructed. Next is the construction of bored piles. During the construction of bored piles, combine the construction of a number of kingposts plugged into the piles. Locating and driving, pressing kingposts H400, H350. Drilling wells to lower the groundwater level and driving return wells outside the diaphragm wall to balance groundwater.

Stage 1: Remove the top soil layer to an elevation of -2.5 m. Installing 2H300 layer 1 (shoring) bracing system at an elevation of -2.0 m.

Stage 2: Excavating the soil from -2.5 to -5.8 m. Pumping water to lower the groundwater level in the foundation pit to an elevation of -5.8 m, and installing the 2H300 layer 2 (shoring) bracing system at the elevation of -5.3 m.

Stage 3: Excavating the soil from -5.8 to -9.1 m. Pumping water to lower the groundwater level in the foundation pit to the elevation of -9.1 m. Construction and installation of 2H300 layer 3 (shoring) bracing system at an elevation of -8.6 m.

Phase 4: Excavation continues from the elevation of -9.1 m to the elevation of the bottom of the foundation (-11.5 m). Pumping water to lower the groundwater level in the foundation pit to the bottom of the foundation pit.

3. RESULTS AND DISCUSSION

3.1

North-south section

Figures 3 and 4 show the horizontal displacement diagrams of the diaphragm walls south and north of the excavation, respectively. Horizontal displacement along the wall depth increases in value according to the construction stages, reaching the maximum value at the final construction stage (stage 4). The maximum horizontal displacement values of the southern and northern diaphragm walls are 3.4 cm and 3.9 cm, respectively. The maximum displacement values appear at the position on the wall located below the bottom of the excavation, about 3 m away. The maximum horizontal displacement of the wall is within the allowable limit according to current regulations⁸.

Figure 3.

Horizontal displacement of the barrette wall south of the excavation pit.

Figure 4.

Horizontal displacement of the barrette wall north of the excavation pit.

Figures 5 and 6 show the moment diagrams of the diaphragm wall south and north of the excavation, respectively. The maximum moment values in diaphragm wall are 1787 kNm and 1176 kNm, respectively, for the south and north walls. The diaphragm wall has a rectangular cross-section bxh=I00×80 cm, the longitudinal reinforcement in tension is 9ϕ28 A-III, the longitudinal reinforcement in compression is 5 ϕ 28 A-III, the durability level of concrete is B25 (Grade 300). The calculation result of the maximum moment value in the wall is 1916 kNm, which is smaller than the limit value M_gh=2192 kNm. Thus, the reinforced concrete structure of the barrette wall ensures bearing capacity.

Figure 5.

Moment of the barrette wall south of the excavation pit.

Figure 6.

Moment of the barrette wall north of the excavation pit.

3.2

East-west section

Figures 7 and 8 show the horizontal displacement graph of the western and eastern barrette walls, respectively, with the maximum horizontal displacement values of 3.0 cm and 2.9 cm, respectively. Similar to the north-south section, the horizontal displacement in the wall depth increases in value with the construction stages. The maximum value at the position on the wall located below the bottom of the excavation, about 3 m away, appeared at the final construction stage. The maximum horizontal displacement of the wall is within the allowable limit⁸.

Figure 7.

Horizontal displacement of the barrette wall west of the excavation pit.

Figure 8.

Horizontal displacement of the barrette wall to the east of the excavation.

Figures 9 and 10 show moment diagrams of the western and eastern barrette walls of the excavation, respectively. The maximum barrette wall moment values are 1664 kNm and 1605 kNm for the West and East diaphragm walls, respectively. Since the diaphragm wall sections have the same cross-sectional structure, the maximum moment value in the wall of the East-West section is 1664 kNm (<M_gh=2192 kNm). Thus, the reinforced concrete structure of the barrete wall ensures bearing capacity.

Figure 9.

Moment of the barrette wall west of the excavation pit.

Figure 10.

Moment of the barrette wall east of the excavation pit.

Since the project of archives of scientific and technological documents and films, photos, and audio recordings was in the design period, the observation data during the construction was impossible to obtain to check the design. Thus, we must implement the comparison between the FEM simulation with another method such as beam on elastic foundation (Winkler model). In addition, we conducted a parameter study to determine the key factors that affect the ground deformation of the nearby structures as a result of the construction of an excavation pit.

4. ADVERSE FACTORS AFFECTING THE DEFORMATION OF NEIGHBORING STRUCTURES’ FOUNDATIONS

4.1

Problem

An excavation problem simulated using a plane problem diagram is considered. Because the excavation is symmetric, only half of the problem needs to be considered (Figure 11). The parameters for simulating the problem are as follows:

Figure 11.

Modeling of an excavation problem.

Excavation dimensions: Length L=30 m; actual width B=60 m (simulated in the planar problem with B=1 m); depth H_k=12 m. Distance from the excavation to the nearby structure: L=1 m. Surface load: q=20 kN/m². Groundwater level at +2.0 m relative to natural ground level. Supporting structure: KING-POST (using H-shaped steel). Support level 1: H300 steel, dimensions: B=300 mm, H=300 mm, t₁=10 mm, t₂=15 mm; Weight: 94 kg/m, cross-sectional area: 118.5 cm², Elastic modulus: E=2×10⁸ kN/m², Longitudinal stiffness: EA=2.37×10⁶ kN; Elevation: -2.00 m; average distance: 4.0 m. Support levels 2 & 3: H400 steel; Dimensions: B=400 mm, H=400 mm, t₁=13 mm, t₂=21 mm; Weight: 171 kg/m; Cross-sectional area: 217.3 cm²; Elastic modulus: E=2×10⁸ kN/m²; Longitudinal stiffness: EA=4.35×10⁶ kN; Elevation: -5.0 m & -7.0 m; Average distance: 4.0 m.

Diaphragm wall: simulated using Plate elements, considered for 1 m of wall length; Concrete: C30, thickness: 60 cm; Depth: 18 m; Elastic modulus: E=2.57×10⁷ kN/m²; Cross-sectional area: A=0.6 m²; Moment of inertia: I=0.018 m⁴; Longitudinal stiffness: EA= 1.54×107 kN/m; Bending stiffness: EI=4.63×10⁵ kNm²/m; Unit weight: w=9.2 kN/m²/m (due to the wall not being completely buried in soil, one side is exposed to ground). Model parameters for diaphragm wall: cross-sectional area A=0.6 m²; unit weight W=9.2 kN/m²/m; moment of inertia I=0.018 m⁴; EA=1.54×10⁷ kN/m; EI=4.63×10⁵ kNm²/m.

Subsoil consists of 2 layers: Layer 1 (clay) with a thickness of 10 m, and layer 2 (mixed clay) with a thickness of 20 m. The subsoil is simulated using Mohr-Coulomb and Hardening-Soil models with values as shown in Table 3. Note that in Table 3, it is assumed E_oed^ref=E₅₀^ref; E_ur^ref=3E₅₀^ref.

Table 3.

Soil model parameters.

	Unit	Mohr-coulomb (undrained)	Hardening-soil (undrained)
Parameter\Model	-	Clay	Mixed clay	Clay	Mixed clay
γ	kN/m3	15.3	19.54	15.3	19.54
γsat	kN/m3	16.14	19.96	16.14	19.96
c’	kN/m2	9.2	18.9	9.2	18.9
ϕ’	degree	10.5	14.5	10.5	14.5
	kN/m2	1624	4220	1624	4220
	kN/m2	-	-	1624	4220
	kN/m2	-	-	4872	12660
v	-	0.3	0.3	-	-
vur	-	-	-	0.2	0.2
k	m/day	1×10-4	1×10-3	1×10-4	1×10-3
m	-			0.5	0.5

The construction sequence for the foundation pit is assumed to consist of a preparation phase and 7 steps as below:

Preparation phase: The work includes: the construction of diaphragm wall; drilling and installation of bored piles, with some kingposts installed concurrently into the piles; positioning and installation of H400 and H350 kingposts; drilling of wells to lower the groundwater level; external water wells beside the diaphragm wall to balance groundwater (water compensation).

Step 1: Excavation of surface soil to elevation -2.0 m.

Step 2: Installation of shoring system (shoring) H300 at elevation -1.0 m.

Step 3: Excavation from elevation -2.0 m to -6.0 m. Pumping water to lower the groundwater level in the pit to elevation of -6.0 m.

Step 4: Installation of shoring system (shoring) H400 at elevation -5.0 m. Pumping water to maintain groundwater level in the pit at elevation -6.0 m.

Step 5: Excavation from elevation -6.0 m to -10.0 m. Pumping water to lower the groundwater level in the pit to elevation of -10.0 m.

Step 6: Construction and installation of shoring system (Shoring) H400 at elevation -9.0 m; pumping water to maintain groundwater level in the pit at elevation -10.0 m.

Step 7: Continued excavation from elevation -10.0 m to the bottom of the footings (-12.0 m); Pumping water to lower the groundwater level in the pit to elevation -13.0 m.

The deformation simulation was conducted using the finite element Plaxis version 8.2⁵. Finite element mesh includes triangular elements with 15 nodal points.

The simulation results by finite element were compared with those by the beam on elastic foundation⁹ (Winkler model).

Figure 12 compares the settlement calculation results of the ground surface using the elastic beam on elastic foundation method⁹; finite element method (Mohr-Coulomb model); and finite element method (Hardening-Soil model), considering the influence of excavation depth H_k(H_k=2 m, 6 m, 10 m, 12 m). In each comparison case, parameter values L and q are fixed (L=1 m, q=20 kN/m²), and the initial groundwater level is fixed at -2 m elevation.

Figure 12.

Comparison of settlement calculation results of the ground surface influenced by the excavation depth.

Figure 13 compares settlement results of the ground surface calculated by the beam on elastic foundation method; by the finite element method (Mohr-Coulomb model); and finite element method (Hardening-Soil model), with considering the influence of distance from excavation edge to adjacent structure L (L=1 m, 2 m, 5 m, 7 m, 9 m, 12 m). In each comparison case, parameters H_k, q, and initial groundwater level are fixed (H_k=12 m, q=20 kN/m², groundwater level at - 2 m elevation).

Figure 13.

Comparison of settlement calculation results of the ground surface influenced by the distance from the excavation edge to the adjacent structure.

Figures 12 and 13 show that at the excavation edge position, both methods provide reasonably consistent settlement results. For the beam on elastic foundation method, the maximum settlement occurs at the excavation edge position, decreasing gradually with distance from the excavation. For the finite element method, settlement of the adjacent structure’s ground surface forms a concave curve. Generally, settlement of the adjacent structure’s ground surface calculated by the finite element method shows larger values compared to settlement calculated by the elastic beam on elastic foundation method. Finite element analysis using the Hardening-Soil model gives larger settlement values for the adjacent structure’s ground surface compared to analysis using the finite element method with the Mohr-Coulomb model.

Figure 14 compares settlement calculation results of the ground surface using the beam on elastic foundation method; finite element method with the Mohr-Coulomb model; and finite element method with the Hardening-Soil model, considering the influence of surface load q (q=10 kN/m², 20 kN/m², 30 kN/m², 40 kN/m² and 50 kN/m²). In each comparison case, again, parameters H_k and L are fixed (H_k=12 m, L=1 m), and initial groundwater level is fixed at -2 m elevation. Figure 14 shows that the influence of surface load on settlement of the adjacent structure’s ground surface according to the elastic beam on elastic foundation method is negligible, whereas, for the finite element method, the influence of surface load q on settlement of the adjacent structure’s ground surface is significant. For the elastic beam on elastic foundation method, the largest settlement of the adjacent structure’s ground surface occurs at the excavation edge position, decreasing gradually with distance from the excavation. For the finite element method, however, settlement of the adjacent structure’s ground surface forms a concave curve. The finite element method with the Hardening-Soil model generally gives larger settlement values for the adjacent structure’s ground surface compared to settlement calculated by the Mohr-Coulomb model.

Figure 14.

Comparison of settlement calculation results of the ground surface influenced by the surface loading.

When comparing the elastic beam on elastic foundation method with the finite element method using the Mohr-Coulomb and Hardening-Soil models, clear differences in settlement of the adjacent structure’s ground surface are observed. These differences in the shape of settlement curves using the finite element method may be due to the influence of excavation support structures and the influence of lowering the groundwater level during construction.

In addition to the parameters H_k, L, and q, settlement calculated by the elastic beam on elastic foundation method also depends on parameters k_r and f₁. Furthermore, k_r and f₁ are determined empirically. Therefore, within the excavation vicinity, settlement of the adjacent structure’s ground surface using the two aforementioned methods may be suitable if appropriate k_r and f₁ coefficients are chosen. Note that k_r is the coefficient considering the influence of the type of soil-retaining structure of the excavation, derived from observed actual building displacements near the excavation; f₁ is an empirical coefficient, representing the maximum surface settlement⁹.

Since the number of comparison cases in this study is limited, for example regarding soil characteristics and excavation support structures, multiple scenarios need to be considered to provide a more comprehensive evaluation of the suitability of simulation parameters using the elastic beam on elastic foundation method compared to the finite element method.

Note that the finite element method has advantages over the elastic beam on elastic foundation method because, in addition to settlement, it also considers lateral displacement of the ground and vertical displacement at the bottom of the excavation. In practice, during deep excavation, both lateral displacement of the ground and the excavation support structures are of significant concern.

In the problem of deep excavation analyzed using the finite element method described above, we have presented a mathematical model to calculate and assess factors influencing deformation of the adjacent structure’s ground surface. However, the excavation support structure model lacks practical significance due to: significant lateral displacement of retaining walls, large internal forces of the walls, large settlement of adjacent structure’s ground surface, and vertical displacement at the bottom of large foundation pits, which may not ensure safety during construction. For this problem case, appropriate construction measures and designs are necessary, such as increasing stability of the excavation support structure by: increasing thickness and depth of diaphragm walls, increasing concrete strength and reinforcing steel of diaphragm walls, enhancing stability of bracing systems, and possibly using preloading method for bracing systems to reduce lateral displacement of bracing systems, thereby reducing lateral displacement of diaphragm walls.

Furthermore, the elastic beam on elastic foundation method does not simulate the range of soil surface behavior as well as the finite element method¹⁰· To verify settlement calculation results of the ground using the elastic beam on elastic foundation method and the aforementioned finite element method, field deformation measurements are necessary.

5. CONCLUSIONS

The influence of the construction process of the deep excavation of the project Archive of scientific and technological documents of film, photo, and audio recording of the National Archives Center III has been simulated with finite element model according to the plane strain problem. Two representative sections: the North-South section and the East-West section have been selected for stress-strain analysis at different excavation stages. The simulation results of the stage construction deformation show that the calculated deformation of the diaphragm wall and the internal force of the diaphragm wall are within the allowable limits. As a result, the impact of the excavation of the excavation on the adjacent works could be under control.

The parameter studies of deformation in the ground of adjacent structures near deep excavations involve two layers of soil and were conducted using the elastic beam on elastic foundation method and the finite element method (Mohr-Coulomb and Hardening-Soil models). The study considers influential parameters such as excavation depth H_k(H_k=2 to 12 m), distance from the excavation to the adjacent structure L (L=1 to 12 m), and construction load q (q=10 to 50 kN/m²). The calculation results indicate: significant parameters affecting the deformation of the ground of adjacent structures near deep excavations include excavation depth H_k, distance L from the excavation edge to the adjacent structure, initial groundwater depth, and surface load q. In general, settlement of the ground surface of adjacent structures increases with increasing Hk, decreasing L, greater depth of initial groundwater level, and higher surface load q. The finite element method demonstrates greater capability in simulating deep excavation problems in a more diverse and realistic manner compared to the elastic beam on elastic foundation method.

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Hong Nam Nguyen and Thi Minh Mai "Analysis of deformations and internal forces of diaphragm walls of a deep excavation by the open excavation method", Proc. SPIE 13279, Fifth International Conference on Green Energy, Environment, and Sustainable Development (GEESD 2024) , 1327926 (26 September 2024); https://doi.org/10.1117/12.3042078

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KEYWORDS

Elasticity

Finite element methods

Deformation

Design

Plastics

Safety

Sand

1.

INTRODUCTION

2.

SIMULATION OF THE DEEP EXCAVATION PROBLEM