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Analysis of the behavior of structures under the effect of progressive rupture of a cavity

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28 ago 2024
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Figure 1:

Schematic diagram of the empirical approach by Peck (1969).
Schematic diagram of the empirical approach by Peck (1969).

Figure 2:

Real model of the cavity.
Real model of the cavity.

Figure 3:

Experimental scale model.
Experimental scale model.

Figure 4:

Overview of Schneebeli rolls.
Overview of Schneebeli rolls.

Figure 5:

Real and scale model of the structure (Caudron et al, 2007).
Real and scale model of the structure (Caudron et al, 2007).

Figure 6:

Model geometry: (a) global geometry, (b) structure, and (c) cavity diagramming.
Model geometry: (a) global geometry, (b) structure, and (c) cavity diagramming.

Figure 7:

Model meshing.
Model meshing.

Figure 8:

Calculation phases.
Calculation phases.

Figure 9:

Phases 1, 2, and 3: (a) Phase 1 (excavation), (b) Phase 2 (soil + structure), and (c) Phase 3 (loading).
Phases 1, 2, and 3: (a) Phase 1 (excavation), (b) Phase 2 (soil + structure), and (c) Phase 3 (loading).

Figure 10:

Cavity rupture process.

(a)Phase 4 (initial cavity rupture)
(b)Phase 5 (2nd cavity rupture)
(c)Phase 6 (3rd cavity rupture)
(d)Phase 7 (total cavity rupture)
Cavity rupture process. (a)Phase 4 (initial cavity rupture) (b)Phase 5 (2nd cavity rupture) (c)Phase 6 (3rd cavity rupture) (d)Phase 7 (total cavity rupture)

Figure 11:

Calculation launch.
Calculation launch.

Figure 12:

Final phase of rupture.
Final phase of rupture.

Figure 13:

Vertical displacements (numerical, experimental, and analytical) of the footing.
Vertical displacements (numerical, experimental, and analytical) of the footing.

Figure 14:

Horizontal displacements (numerical, experimental, and analytical) of the footings.
Horizontal displacements (numerical, experimental, and analytical) of the footings.

Figure 15:

Differences in displacements of each footing among the three methods.
Differences in displacements of each footing among the three methods.

Figure 16:

Models used in this study: (B) width of the footing, (H) depth of the cavity, (L) cavity spacing, (a) cavity height, and (b) cavity width.
Models used in this study: (B) width of the footing, (H) depth of the cavity, (L) cavity spacing, (a) cavity height, and (b) cavity width.

Figure 17:

Stress in the yy plane.
Stress in the yy plane.

Figure 18:

Vertical and horizontal displacements according to the three ratios.
Vertical and horizontal displacements according to the three ratios.

Figure 19:

The variation in displacements under the three ratios.
The variation in displacements under the three ratios.

Figure 20:

Displacement assembly according to the three ratios.
Displacement assembly according to the three ratios.

Geo-mechanical characteristics of scale model soils_

Characteristics Unit Pulverulent soil Coherent soil
Young's modulus (E) MPa 50–100 50–100
Friction angle (φ) ° 26 28–30
Cohesion (c) KPa ≈ 0 ≈200
Poisson's ratio (ν) / 0.3 0.3
Density (ρ) kg/m3 2200 2200

Properties of structural elements_

Parameters Name Unit Value
Type of behavior Material type - Elastoplastic
Normal stiffness EA kN/m 132000
Flexural rigidity EI KNm2/m 4389
Equivalent thickness d m 0.632
Weight w KN/m/m 10
Poisson's ratio ν - 0.35

Summary of conducted research studie_

Author Year Objective Type
Nakai et al. 1997 Investigate the effect of 3D and expansion on ground movements during tunnel excavation Experimental
Dyne 1998 Analyze the different parameters: the opening of the cavity, the width of the cavity, and the height of the covering Experimental 2D scale model
Burd et al. 2000 Study soil-structure interaction during tunneling under masonry structures and analysis Numerical MEF-OXFEM
Laefer 2001 Study the damage to structures on shallow foundations subject to soil movements induced by excavation Experimental (a small-scale model of 1/10th).
Mahamma 2002 Study the soil-structure interaction phenomena during the collapse of a mine gallery. The collapse of the mine gallery was modeled by successive sinking of a cylinder along the axis of propagation of the rupture Experimental
Shanin et al. 2004 The study of the effect of ground movements and their mechanical behavior during tunnel excavation. Experimental trap model
Boumalla 2005 Vary a number of parameters such as the opening of the cavity, the height of the cover, the rate of initiation of a melt, or the subsidence of the ground Experimental
Sung et al. 2006 Analyze the settlements and ground pressure at the surface due to the tunnel in the cases without and with the foundation structure in the vicinity. Experimental
Castro et al. 2007 Study the “block caving” mining method, not the movements that occur on the surface of the land Experimental large-scale 3D model
Trueman et al. 2008
Lee & Bassett 2007 Simulate the deformation of the tunnel by changing its diameter, to investigate the behavior of existing foundations located near the tunnel Experimental
Kikumoto et al. 2009
Caudron 2007 Characterize the influence of soil-structure interaction during the formation of a sinkhole Experimental and numerical
Deck and Anirudth 2010 To investigate the phenomenon of soil-structure interaction due to mine subsidence, taking into account the influence of length, rigidity of the structure, mechanical properties of the soil, and intensity of subsidence. Numerical 2D model CESAR LCPC
Boramy Hor 2012 Simulate ground movements and their consequences on the surface. Experimental/numerical 3D physical model
Al Heib et al. 2013 Understanding sinkhole consequences on masonry structures using a large small-scale physical modeling. The paper presents the main results of the small-scale physical model designed to study the consequences of subsidence on structures. Present the transfer of movements from the soil to the structure. The objective is to understand and then to predict the real behavior and the damage of structures on subsidence areas. Experimental
Nghiem et al. 2014 Physical model for damage prediction in structures due to underground excavations: a small-scale physical model (1/40 scale factor on the dimensions) under normal gravity. It has been designed for developing and validating experimentally new methods of prediction of damages to masonry structures induced by subsidence (generally resulting from underground excavations of tunnels and mines) Experimental
Keawsawasvong 2021 Limit analysis solutions for spherical cavities in sandy soils under overloading. An investigation on the stability of spherical cavities in sandy soils under overloading at the ground surface is carried out in this study. By using finite element limit analysis, a spherical cavity is numerically simulated under an axisymmetric condition, and the lower and upper bound solutions of the stability of spherical cavities can be obtained Numerical
Yongyao et al. 2023 A numerical simulation study on the evolutionary characteristics of the damage process of karst soil cavity under positive pressure effect Numerical
Keba and Isobe 2024 Bearing capacity of a shallow foundation above the soil with a cavity based on a rigid plastic finite element method. Based on the rigid plastic finite element method (RPFEM), this study investigates the performance of the footing on the soil with a cavity. The RPFEM is used in plane strain conditions and necessitates only a few materials to predict the bearing capacity: the unit weight of the soil, the cohesion, the shear resistance angle, and the dilation angle Numerical

List of scale factors_

Symbol Scale factor concerned Dimension Value
L* Length of reference L 1/40
x* Coordinates L 1/40
E* Modulus of elasticity ML−1 t−2 3/40
ρ* Density ML−3 3
g* Acceleration of gravity Lt−2 1
F* External punctual force MLt−2 3/64000
p* Superficial force ML−1 t−2 3/40
U* Displacement L 1/40
σ* Constraint ML−1 t−2 3/40
γ* Inertia acceleration Lt−2 1

Geo-mechanical characteristics of different materials (Caudron, 2007)_

Layer Materials E (MPa) υ Rtraction (MPa) Cohesion (MPa) φ (°)
8 Marls 70 0.25–0.30 0.30 0.80 28
2 and 5 Stones 100 0.25–0.30 0.30 0.80 29
6 Clay sand 130 0.25–0.30 0.20 1.2 30
3 and 9 Limestone 20 0.25–0.30 0.80 2.00 31
7 Stones 200 0.25–0.30 01 1.00 35
4 Marls 50 0.25–0.30 0.1 0.20 26
1 Stones 50 0.25–0.30 0.20 0.40 27

List of similarity laws_

Number Similarity law Meaning of scale factors
1 x*/L*=1 Equality of coordinates relative to length scale
2 U*/L*=1 Equality of displacements relative to length scale
3 U0*/L*=1 Equality of displacements at origin relative to length scale
4 g**=1 Equality of acceleration scale to gravity scale
5 E*L*2/F*=1 Conservation of the ratio of elasticity modulus scale by length squared to force scale
6 Y*t*2/L*=1 Identity of acceleration and length scales as time cannot be altered
7 P*L*2/F*=1 Conservation of the ratio of pressure scale times length squared to force scale
8 0*L*2)/F*=1 Conservation of the ratio of stress scales times length squared to force scale
9 *γ*L3*)/F*=1 Conservation of the ratio between scales of quantities determining inertia force relative to force scale

Structure characteristics in real size and scale model_

Characteristics Values
Real model Scale model
Module (MPa) 33000 2475
Section (m2) 0.04 25×10−6
Inertia (m4) 1.33×10−4 52×10−12
Loading (kPa) 10 0.75

Empirical formulas for determining i (Dolzhenko, 2002)_

Authors Proposed expression Soil type Calculated i value
Atkinson & Potts. (1977) i = 0.25(1.5C + D) Dense sands with surcharge 3.65 m
Oteo & Sagaseta. (1982) i = 0.525H + 0.42R Granular soils 5.67 m
Dyer et al. (1986) i = 0.29H Loose to medium dense sand 2.60 m
Al Abram (1998) i = 0.15H + 0.5D Analogical soil 3.60 m

Soil properties_

Parameters Name Unit Pulverulent soil Coherent soil Air
Material model Model - Mohr-Coulomb Mohr-Coulomb Mohr-Coulomb
Material type Type - Drained Drained Drained
Soil unit weight above phreatic level γunsat kN/m3 17 20 5
Soil unit weight below phreatic level γsat kN/m3 19 22 5
Permeability in horizontal direction kx m/day 1 0 1
Permeability in vertical direction ky m/day 1 0 1
Young's modulus E kN/m2 100000 100000 5
Poisson's ratio ν - 0.3 0.3 0.1
Cohesion c kN/m2 2 200 1
Friction angle φ ° 26 26 5
Dilatancy angle ψ ° 7 9 1
Strength reduction factor interne Rinter - 1 1 1
Lingua:
Inglese
Frequenza di pubblicazione:
4 volte all'anno
Argomenti della rivista:
Geoscienze, Geoscienze, altro, Scienze materiali, Compositi, Materiali porovati, Fisica, Meccanica e dinamica dei fluidi