Numerical study of parameters influencing the response of flexible retaining walls

1996 ◽  
Vol 33 (2) ◽  
pp. 290-308 ◽  
Author(s):  
Hans H Vaziri
Keyword(s):  
Finite Element ◽  
Stiffness Matrix ◽  
Numerical Study ◽  
Lateral Displacement ◽  
Limit Equilibrium ◽  
Retaining Wall ◽  
Practical Interest ◽  
Elastic Beam ◽  
Retaining Walls ◽  
Wall Stiffness

A practical numerical model is described for analysis of flexible retaining walls. In terms of capabilities, the model fits between traditional limit equilibrium methods and full finite element approaches; it overcomes many of the limitations associated with the former but is not equipped with the versatility offered by the latter. Using an approach similar to that adopted in boundary-element based models, the wall stiffness is represented by a series of elastic beam elements whose stiffness is combined with that of the prestressed struts and the soil to form, the overall stiffness matrix. The stiffness matrix of the soil is obtained by inversion of flexibility matrices generated by interpolation and sealing of flexibility matrices calculated for a simplified soil model using finite element methods. The soil behaves linearly elastically, as long as the pressures correspond to stress levels lying between the limits. Where the lateral displacement of the wall corresponds to a pressure outside of these allowable limits, correction forces are added until the resulting pressures are within the active or passive pressures. Arching is permitted by considering the forces acting on the wall compared with the forces consistent with possible failure surfaces within the soil. Other features that can be accomodated by the model include struts, variations in water table, and the effects of surcharges. The proposed model has been shown to capture the displacement, anchor loads, and lateral stresses for several field problems. Based on these studies and other field applications of the model a number of points have been observed that are of practical interest; these points are separately listed. Key words: numerical analysis, retaining wall, anchor, arching, soil–structure interaction, deflection.

scholarly journals Numerical Modelling of Structures Adjacent to Retaining Walls Subjected to Earthquake Loading

Geosciences ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 486
Author(s):  
Xiaoyu Guan ◽  
Gopal S. P. Madabhushi
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Retaining Wall ◽  
Free Field ◽  
Retaining Walls ◽  
Earthquake Loading ◽  
Bending Moments ◽  
Sheet Pile ◽  
Novel Approach ◽  
Active Zones

In an urban environment, it is often necessary to locate structures close to existing retaining walls due to congestion in space. When such structures are in seismically active zones, the dynamic loading attracted by the retaining wall can increase. In a novel approach taken in this paper, finite element-based numerical analyses are presented for the case of a flexible, cantilever sheet pile wall with and without a structure on the backfill side. This enables a direct comparison of the influence exerted by the structure on the dynamic behaviour of the retaining wall. In this paper, the initial static bending moments and horizontal stresses prior to application of any earthquake loading are compared to Coulomb’s theory. The dynamic behaviour of the retaining wall is compared in terms of wall-top accelerations and bending moments for different earthquake loadings. The dynamic structural rotation induced by the differential settlements of the foundations is presented. The accelerations generated in the soil body are considered in three zones, i.e., the free field, the active and the passive zones. The differences caused by the presence of the structure are highlighted. Finally, the distribution of horizontal soil pressures generated by the earthquake loading behind the wall, and in front of the wall is compared to the traditional Mononobe-Okabe type analytical solutions.

scholarly journals Influence of parameters of retaining walls and loose soils on the stability of slopes in the new construction of residential complexes

2020 ◽  
pp. 65-75
Author(s):  
Liudmyla Skochko ◽  
Viktor Nosenko ◽  
Vasyl Pidlutskyi ◽  
Oleksandr Gavryliuk
Keyword(s):  
Finite Element ◽  
Slope Stability ◽  
Cross Sections ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Natural State ◽  
Soil Parameters ◽  
Stability Of Slopes ◽  
The Stability ◽  
Stage 1

The stability of the slope in the existing and design provisions is investigated, the constructive decisions of retaining walls on protection of the territory of construction of a residential complex in a zone of a slope are substantiated. The stability of the slope when using rational landslide structures is estimated. The results of the calculation of the slope stability for five characteristic sections on the basis of engineering-geological survey are analyzed. For each of the given sections the finite-element scheme according to the last data on change of a relief is created. The slope was formed artificially by filling the existing ravine with construction debris from the demolition of old houses and from the excavation of ditches for the first houses of the complex. Five sections along the slope are considered and its stability in the natural state and design positions is determined. Also the constructive decisions of retaining walls on protection of the territory of construction of a residential complex as along the slope there are bulk soils with various difference of heights are substantiated. This requires a separate approach to the choice of parameters of retaining walls, namely the dimensions of the piles and their mutual placement, as well as the choice of the angle of the bulk soil along the slope. The calculations were performed using numerical simulation of the stress-strain state of the system "slope soils-retaining wall" using the finite element method. An elastic-plastic model of soil deformation with a change in soil parameters (deformation module) depending on the level of stresses in the soil is adopted. Hardening soil model (HSM) used. Calculations of slope stability involve taking into account the technological sequence of erection of retaining walls and modeling of the phased development of the pit. The simulation was performed in several stages: Stage 1 - determination of stresses from the own shaft, Stage 2 - assessment of slope stability before construction, Stage 3 - installation of retaining wall piles, Stage 4 - assessment of slope stability after landslides. Based on these studies, practical recommendations were developed for the design of each section of the retaining wall in accordance with the characteristic cross-sections.

scholarly journals Seismic internal stability assessment of geosynthetic reinforced earth retaining wall in cohesive soil using limit analysis

2019 ◽  
Vol 281 ◽  
pp. 02008
Author(s):  
Hicham Alhajj Chehade ◽  
Daniel Dias ◽  
Marwan Sadek ◽  
Fadi Hage Chehade ◽  
Orianne Jenck
Keyword(s):  
Limit Analysis ◽  
Limit Equilibrium ◽  
Retaining Wall ◽  
Cohesive Soil ◽  
Retaining Walls ◽  
Reinforced Soil ◽  
Seismic Stability ◽  
Collapse Mechanism ◽  
Kinematic Theorem ◽  
Soil Retaining Walls

Assessment of internal seismic stability of geosynthetic reinforced cohesive soil retaining walls with likelihood for developing cracks in the failure mechanism is typically done with the limit equilibrium method. However, in this paper, the kinematic theorem of limit analysis combined with the discretization method are used to implement the crack formation in the collapse mechanism in the internal seismic assessment of geosynthetic reinforced soil retaining walls within the framework of the pseudo-static approach. The presence of the crack leads to an increase of the required reinforcement strength that prevent the failure of the structure.

Studying The Settlement of Backfill Sandy Soil Behind Retaining Wall Under Dynamic Loads

2020 ◽  
Vol 38 (7A) ◽  
pp. 992-1000
Author(s):  
Reham E. Hamdi ◽  
Mohammed Y. Fattah ◽  
Mohammed F. Aswad
Keyword(s):  
Relative Density ◽  
Sandy Soil ◽  
Limit Equilibrium ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Dynamic Loads ◽  
Dense Sand ◽  
Burden Test ◽  
Long Time ◽  
Cohesion Less Soil

For a long time, the seismic examination of retaining walls has been contemplated by a few strategies dependent on the basic augmentation of Coulomb's limit equilibrium investigation. These techniques cannot gauge the removal of the refill soil upheld by the wall. A trial examination is completed to contemplate the vertical settlement on sandy soil under dynamic loads with other burden amplitudes, vibration frequencies, relative density, and various separations between the establishment and holding divider. The model balance utilized in this investigation is square. Dynamic burden test is done on cohesion less soil with three burden amplitudes (0.25 ton, 0.5 ton and 1 ton), three vibration recurrence (0.5 Hz, 1 Hz and 2 Hz), two density of sandy soil (30% loose sand and 70% dense sand) and three unique separations between the establishment and retaining wall. It has been seen that the change is increment with the burden of abundance and decreased by increasing the separation between the establishment and retaining wall. There is an unimportant result of recurrence on the aggregate settlement. The settlement decrement by incrementing the relative density

Numerical Study of Plastic Strains on Slope Instability

2012 ◽  
Vol 548 ◽  
pp. 363-366
Author(s):  
Mao Hu Wang ◽  
Zhen Liang Xu
Keyword(s):  
Finite Element ◽  
Slope Stability ◽  
Safety Factor ◽  
Numerical Study ◽  
Limit Equilibrium ◽  
Strength Reduction ◽  
Slope Instability ◽  
Open Pit ◽  
Instability Criterion ◽  
Incremental Search

This article simulates an open pit slope stability using the ANSYS software, which is based on the finite element strength reduction theory, three kinds of slope instability criterion of the strength reduction method are applied to judge whether the slope is on the limit equilibrium state, the incremental search method is used to search the safety factor of the slope stability, and the results show that, the slope body damages when the plastic zone developed from the top to the bottom, in the numerical simulation the finite element iteration calculation didn’t just converge, the corresponding former level of reduction factor is the safety factor, This article can have a guiding significance on the safety production of the open-pit mine.

Microstructure-Based Random Finite Element Method Model for Freezing Effects in Soils and Cold Region Retaining Walls

2020 ◽  
Vol 2674 (11) ◽  
pp. 708-719
Author(s):  
Shaoyang Dong ◽  
Xiong (Bill) Yu
Keyword(s):  
Finite Element ◽  
Retaining Wall ◽  
Element Model ◽  
Retaining Walls ◽  
Frozen Soils ◽  
Frost Action ◽  
Mechanical Responses ◽  
Random Finite Element Method ◽  
Random Finite Element ◽  
Method Model

This paper describes the development of a random finite element model that allows holistic simulation of the phase transition and consequent development of internal stress and volume changes in frozen soils. The simulation capabilities of the model are first validated with laboratory scale experiments. The validated model is then implemented to study the soil lateral stress on the retaining wall subjected to frost action. The results show that the frost action leads to an increase of lateral stresses along the retaining wall. Strategies to mitigate the frost loads on the retaining wall are analyzed with this model; drainage of water in the backfill and use of thermal insulation layer both help to mitigate the lateral frost loads. Overall, by accounting for the spatial nonhomogeneity and coupled thermo-mechanical responses in frozen soils, the model provides holistic simulation of the responses of retaining walls subjected to freezing conditions.

Seismic Strengthening Methods and Analysis of Instability of Gravity Retaining Walls

2014 ◽  
Vol 971-973 ◽  
pp. 2141-2146
Author(s):  
Tian Zhong Ma ◽  
Yan Peng Zhu
Keyword(s):  
Safety Factor ◽  
Limit Equilibrium ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Retaining Walls ◽  
Theoretical Formula ◽  
Seismic Strengthening ◽  
Gravity Retaining Wall ◽  
Overturning Stability ◽  
The Stability

Using the frame supporting structure of pre-stressed anchor bolt seismic strengthening technology reinforced the instability of gravity retaining wall. Earth pressure of retaining wall in seismic reinforcement after shall take between active and static earth pressure for the form of the distribution . In this paper, based on the limit equilibrium theory, and the whole stability for retaining walls is analysis, the theoretical formula of the stability safety factor between stability against slope and overturning safety factor is derived. By calculation and comparative analysis with an example, the stability safety factor of gravity retaining wall with introducing this strengthening technology is improved obviously. Keywords: frame anchor structure; seismic strengthening; anti-slip and anti-overturning; stability coefficient;

scholarly journals Numerical Study of Geosynthetic-Reinforced Soil Wall Subjected to Static Footing Loading

2021 ◽  
Vol 17 ◽  
pp. 13-20
Author(s):  
Ananya Srivastava ◽  
Sagar Jaiswal ◽  
Vinay Bhushan Chauhan
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Numerical Study ◽  
Complex Structure ◽  
Retaining Walls ◽  
Ultimate Bearing Capacity ◽  
Reinforced Soil ◽  
Geosynthetic Reinforced Soil ◽  
Reinforced Soil Wall ◽  
Offset Distance

This study intends to examine the behavior of a GRS wall with static footing loading above it, while varying the positions of the footing. For the study of behavior of such complex structure, finite element modeling is handy and enables to look into the various stress/strain developed in the numerical model. In view of the above, a series of finite element (FEM) simulations using a software (Optum G2) is performed for the analysis of the GRS wall. The governing parameters, such as footing width (B), reinforcement length (L), offset distance (D), are evaluated and the effect of these factors on the ultimate bearing capacity (q) and settlement (s) of the footing is presented in this study. The results depict that the settlement of the footing substantially reduced in the range of 36% and its ultimate bearing capacity is increased to 42% more than the conventional retaining walls.

scholarly journals Simplified Method for Calculating the Active Earth Pressure on Retaining Walls of Narrow Backfill Width Based on DEM Analysis

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Minghui Yang ◽  
Bo Deng
Keyword(s):  
Urban Areas ◽  
Limit Equilibrium ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Friction Angle ◽  
Retaining Walls ◽  
Cohesionless Soil ◽  
Particle Flow Code ◽  
Active Earth Pressure ◽  
Dem Analysis

Spaces for backfills are often constrained and narrowed when retaining walls must be built close to existing stable walls in urban areas or near rock faces in mountainous areas. The discrete element method (DEM), using Particle Flow Code (PFC-2D) software, was employed to simulate the behavior of cohesionless soil with narrow width behind a rigid retaining wall when the wall translation moved away from the soils. The simulations focused on the failure model of the soil when the movement of the wall reaches the value where active earth pressure occurs, and the shape of the sliding surface was captured. Then, based on the limit equilibrium method with the obtained slip surfaces in PFC-2D, a simplified analytical method is presented to obtain a solution of the active earth pressure acting on rigid retaining with narrow backfill width. The point of application of the active earth pressure is also obtained. The calculated values agree well with those from physical tests in the previous literature. Furthermore, the effects of the width of the backfill, internal friction angle of soil, and wall-soil friction angle on the distribution of active earth pressure are discussed.

scholarly journals Evaluating the Role of Geofoam Properties in Reducing Lateral Loads on Retaining Walls: A Numerical Study

2021 ◽  
Vol 13 (9) ◽  
pp. 4754
Author(s):  
Muhammad Imran Khan ◽  
Mohamed A. Meguid
Keyword(s):  
Numerical Study ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Retaining Walls ◽  
Expanded Polystyrene ◽  
Wall Structure ◽  
Eps Geofoam ◽  
Lateral Earth Pressure ◽  
Backfill Soil

Expanded polystyrene (EPS) geofoam is a lightweight compressible material that has been widely used in various civil engineering projects. One interesting application of EPS in geotechnical engineering is to reduce the lateral earth pressure on rigid non-yielding retaining walls. The compressible nature of the EPS geofoam allows for the shear strength of the backfill soil to be mobilized, which leads to a reduction in lateral earth pressure acting on the wall. In this study, a finite element model is developed and used to investigate the role of geofoam inclusion between a rigid retaining wall and the backfill material on the earth pressure transferred to the wall structure. The developed model was first calibrated using experimental data. Then, a parametric study was conducted to investigate the effect of EPS geofoam density, relative thickness with respect to the wall height, and the frictional angle of backfill soil on the effectiveness of this technique in reducing lateral earth pressure. Results showed that low-density EPS geofoam inclusion provides the best performance, particularly when coupled with backfill of low friction angle. The proposed modeling approach has shown to be efficient in solving this class of problems and can be used to model similar soil-geofoam-structure interaction problems.

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