Cantilever Retaining Wall Research Articles

Examining Active Earth Pressure: Translational Mode Impacts on Cantilever Retaining Walls with Relief Shelves

Examining Active Earth Pressure: Translational Mode Impacts on Cantilever Retaining Walls with Relief Shelves

Optimization Of Cantilever Retaining Wall Design Using Improved Teaching-Learning-Based Optimization Algorithms

Retaining structures play a crucial role in geotechnical engineering to support soil levels, prevent slope failure, and create flat surfaces for construction. Designing these structures involves optimizing internal and external stability while minimizing material usage and cost. This study focused on optimizing reinforced concrete cantilever retaining walls using the Teaching-Learning Based Optimization (TLBO) algorithm and an improved version (I-TLBO) with agents. In the context of the study, geometric-structural design variables, geotechnical -structural constraints, and optimization processes were examined. Minimizing weight and minimizing cost of the wall were the objectives considered in the cantilever retaining wall design process. The optimization results were compared with other algorithms in the literature, such as genetic algorithms, evolutionary strategies, and particle swarm optimization. The improved TLBO algorithm demonstrated superior performance, achieved lower design dimensions, and reduced costs. It provided more efficient solutions that pushed design constraints closer to their limits, resulting in a cost-effective and structurally sound cantilever retaining wall design. As a result of the study, the I-TLBO algorithm was found to be more cost and weight-effective than other methods in the optimization of cantilever retaining wall design.

The Behavior of Concrete Cantilever Retaining Walls During Far-Field and Near-Fault Earthquakes

Abstract The dynamic behavior of retaining walls is a complicated subject and a considerable design challenge, particularly under seismic conditions. Seismologists and investigators have an interest in near-fault earthquakes with significant velocity pulses because it can cause considerable displacements in constructions with respect to far-field earthquakes and consequently rise the hazard of earthquake-caused failure of structures. Despite there are several studies have investigated the seismic behavior of retaining structures, but the researches about retaining walls subjected to the influence of near fault like pulse earthquakes is still not adequate. The current study targets to numerically assess the dynamic performance of concrete cantilever retaining walls during far field ground motions (FFGMs) and near-fault ground motions (NFGMs). The nonlinear analysis of time history is conducted using the finite element method for three cantilever retaining wall models. The results of the analysis gained in terms of top horizontal displacement of the wall, active seismic earth pressure, and acceleration response of the system, which have been considered to recognize the impact of near fault earthquake on retaining structures. Additionally, the influence of different PGA of NF and FF earthquakes has been studied.

Numerical Investigation of Seismic Behaviour for a Flexible Cantilever Retaining Wall with Cohesive Backfill

In the seismic design of flexible cantilever walls retaining cohesive backfill soil, the common practice is to neglect the cohesion effect. Dynamic lateral earth pressure is typically evaluated based on approaches primarily intended for cohesionless soils or through analytical pseudo-static methods. Nevertheless, both experimental and theoretical evidence has demonstrated significant effects due to soil cohesion that are not accounted for by these methods. This study involved finite element modeling (FE) of a flexible cantilever wall with a height of 5.4m, supporting homogeneous cohesive backfill under initial static and seismic loadings. The calculated active earth thrust was then compared with values obtained experimentally and through conventional analytical methods. The obtained results indicate that the presence of soil cohesion significantly reduces seismic demands on flexible cantilever retaining walls, resulting in a substantial reduction of seismic active earth pressures and total seismic thrust by up to 50% and 52%, respectively. It enhances also the overall stability of the system by shifting the point of application of seismic thrust toward the base of the wall, thereby increasing the safety margin. In addition, it significantly decreases the wall displacement at the stem top, with reductions of up to 104% compared with the case involving cohesionless backfill. It was observed that the conventional methods recommended by some seismic regulations largely underestimate seismic active pressure.

Analytical and Numerical Study of the Hydro-Mechanical Behavior of a Cantilever Retaining Wall in Upward Seepage Conditions

Analytical and Numerical Study of the Hydro-Mechanical Behavior of a Cantilever Retaining Wall in Upward Seepage Conditions

Analysis of Cantilever Retaining Wall as Landslide Mitigation on a Tributary of Cisadane River Bogor City

Bogor City has a high level of rainfall and is included in an area with a high potential for landslides. In March 2021, there was a landslide in a densely populated residential area at RT. 02/03 Cipaku Village, Bogor Selatan District. The landslide occurred on the slopes at the tributary of Cisadane River and adjacent to the nearest connecting bridge. The length of the landslide is 6 meters and as high as 7 meters from the water surface. Mitigation steps to prevent subsequent landslides are needed by constructing a retaining wall, so a cantilever-type retaining wall is chosen by considering the soil parameters and landslide conditions. The results of the analysis show that the stability of the retaining wall against shear (Fs) = 1.04 < SF = 1.5 and for stability against overturning (Fo) = 0.56 < SF = 1.5. Thus, the overall retaining wall is not able to withstand the load of the soil behind it. In terms of stability to the bearing capacity of the soil, the ultimate soil capacity (qs) = 94.149 kN/m2 > V = 243.535 kN/m2. Thus, the subgrade can withstand the load of the retaining wall. Therefore, to meet shear stability and overturning stability, the retaining wall is reinforced by using a bored pile foundation. The results of the foundation analysis showed that the allowable capacity (Qs) was obtained at 584.8 kN.

Optimum Cost Prediction of Reinforced Concrete Cantilever Retaining Walls

Reinforced concrete cantilever retaining walls (RCCRWs) are widely used in civil engineering projects as a common type of retaining structure. The design of these structures focuses on ensuring safety against various failure scenarios and compliance with standard building code requirements. This research aims to enhance the design process of RCCRWs by developing a specific code and optimizing it through a metaheuristic-based algorithm. In this study, the cost prediction of RCCRWs is also investigated through a parametric study involving key variables such as wall height, seismic zone, backfill material properties, and backfill inclination angle. To achieve this, non-linear regression analysis is employed to establish an empirical correlation, enabling cost estimation for optimized RCCRWs. The resulting prediction equation is simple to use, requiring only limited inputs. Therefore, it can be applied during the initial stages of a project, making a valuable contribution in determining approximate costs for RCCRW projects.

Determination of Passive Earth Pressure on a Cantilever Retaining Wall in a Narrow Foundation Pit Based on Logarithmic Spiral Sliding Surface

The distribution of passive earth pressure on a cantilever flexible retaining wall in a narrow foundation pit is significantly affected by the adjacent retaining wall and the width of the foundation pit. The deformation mode of the cantilever retaining wall rotating around the displacement zero point makes the soil layer below the displacement zero point retain a nonlimit passive state. The functional relationship between soil mechanical parameters and horizontal displacement in the nonlimit state region, considering the influence of displacement, is established. A new combined failure mode of the soil mass in the passive zone of the narrow foundation pit is proposed, which is the logarithmic spiral fracture surface in the nonlimit state region and the broken line fracture surface in the limit-state region. On this basis, a passive earth pressure calculation model of a narrow foundation pit is proposed and solved by differential layer method. The solution of the passive earth pressure coefficient strictly meets the static equilibrium conditions in vertical and horizontal directions as well as the moment equilibrium conditions. A numerical example is used to analyze the influence of the width of the foundation pit. The smaller the narrow foundation pit width, the greater the passive earth pressure in the lower soil layer and it even greatly exceeds the Coulomb earth pressure distribution. The earth pressure distribution acting on the lower part of the wall near the zero point of displacement decreases sharply and bends. The passive earth pressure distribution is calculated by the theoretical method and compared with the laboratory model test results as well as the engineering test results. It is found that the proper selection of the initial soil mechanical parameters affects significantly the magnitude and distribution of lateral pressure in the nonlimit state region. When the internal friction angle of soil φ0 is small, the lateral pressure in the lower nonlimit state area is relatively small. When both φ0 and δ0 are small, the pressure distribution is closer to the test results and the existing theoretical calculation results.

Comparative Analysis of Cantilever Retaining Wall with and without Column

Abstract: Retaining walls play a crucial role in civil engineering projects, providing stability to soil, preventing erosion, and mitigating landslides. To design and analyse these walls effectively, a profound understanding of soil mechanics, structural engineering principles, and various wall configurations is required. One notable configuration is the Cantilever Retaining Wall, which is known for its simplicity and effectiveness in resisting lateral earth pressures. However, for taller retaining walls, incorporating a column has shown potential in achieving greater cost-efficiency. This research aims to conduct a comprehensive analysis of cantilever retaining walls, comparing those with and without a column system. The study utilizes manual calculations, as well as software tools like STAAD Pro and Excel spreadsheets, for design optimization. Adherence to the guidelines specified in the Indian Standard IS 456:2000 for reinforced concrete structures ensures compliance with industry standards. The research involves a thorough examination and design of both the Cantilever Retaining Wall (CRw) and the Column Cantilever Retaining Wall (CCRw), considering a 35-meter span and heights ranging from 3 to 9 meters. Through a comprehensive evaluation of construction costs, this study concludes that the CCRw configuration offers superior costeffectiveness compared to the CRw configuration.

Experimental and Theoretical Study for a Displacement-Controlled Design Method of Embedded Cantilever Retaining Walls (Piles)

Displacement control is critical to the design of retaining walls, especially in urban areas, to avoid any potential damage to adjacent structures during excavations. In this study, model tests are first conducted to investigate the stress and deformation mechanisms of an embedded cantilevered retaining (ECR) wall during excavations. The development of the wall top displacement and the active and passive earth pressures acting on the ECR walls during excavations are studied. Upon the experimental observations, a displacement-dependent earth pressure coefficient is proposed to derive an analytical solution to predict both the active and passive earth pressure acting on the ECR wall (pile), where the displacement value and displacement mode of the ECR wall (pile) are taken into account. Comparisons between the model predictions and test results are carried out. A good agreement is observed, which shows the validity of the proposed solution. Based on the proposed solution, a displacement-controlled method for the design of ECR walls (piles) that takes into account the location of the rotation point is proposed. Parametric studies are conducted to demonstrate the impact of deformation control and excavation depth on the design parameters of ECR walls (piles).

Seismic Active Earth Pressure of Infinite Width Backfilled Soil on Cantilever Retaining Wall with Long Relief Shelf under Translational Mode

In the area of high seismic intensity, there were few methods for calculating active earth pressure (Ea). Especially for the cantilever retaining wall with long relief shelf (CRW-LRS), the theoretical method lags behind the practical engineering. The seismic active earth pressure (ES) of the CRW-LRS subject to translational mode was researched. By finite element method (FEM), the failure mode of the active limit state under seismic load was evaluated. The results show that the backfill behind the wall generates the first sliding surface at the wall heel bottom, the second at the wall heel top, and the third at the relief shelf top. The calculation formula of ES under long relief shelf failure mode was proposed using the limit analysis method of a horizontal differential layer. The calculation results were compared with the FEM results to prove the rationality and reliability of the theoretical solution. The effects of relief shelf relative length (l) and position (m), wall heel length (n), internal frictional angle of the backfill (ϕ), seismic horizontal acceleration (ah), and seismic vertical acceleration (aV) on ES were studied.

Active Earth Pressure against Cantilever Retaining Walls with a Long Relief Shelf in Rotation about the Top

A cantilever retaining wall with a long relief shelf (CRW-LRS) is a particular type of retaining wall, but no studies have yet reported on rotation about the top of this type of retaining wall. This work studied failure mechanisms in semi-infinite non-cohesive soils in rotation about the top using the finite element elastoplastic analysis method (FEEA). By considering the influence of both the relief shelf and rotational stress from the soil, a formula for calculating the active earth pressure (Ea) was developed using the horizontal differential layer limit analysis method. Four different parameters were studied, i.e., unloading plate's geometric conditions, heel length and the internal friction angle of the backfill, in terms of their influence on the Ea distribution, resultant force etc. The lowest Ea was found when the relief shelf' relative position m = 0.4.

Displacement-Controlled Analysis of Embedded Cantilever Retaining Walls

An uneconomical design of embedded cantilever retaining (ECR) walls unnecessarily restricts the lateral wall movement, whereas unwarranted wall displacement induced ground settlement can jeopardize the functionality of neighboring structures. Thus, correct estimation of the wall displacement under working conditions is imperative for a safe and economical design. This paper presents an analytical method for the displacement-controlled analysis of ECR walls in cohesionless soils, which can be used to calculate the required embedment depth for a prescribed wall displacement and retaining heights. Alternatively, when the retaining height and the embedment depth of an ECR wall are given, the lateral wall displacement can also be calculated. A displacement-dependent earth pressure mobilization model is proposed to derive the mobilized soil stresses along the wall height. The required embedment depth of the wall is determined by assuming rigid rotation of the wall about a point near the toe and satisfying the horizontal force and moment equilibriums. Analytical formulations are provided to determine the bending moment distribution and the ground settlement. The effect of construction by excavation is also taken into the analysis. The results show that the required embedment depth and the maximum bending moment increase exponentially with decreasing wall displacement. The depth of the pivot point is located at around 0.9 times the embedment depth. The validity of the proposed method is demonstrated by comparing the calculated results with those of the available numerical and experimental studies. The proposed method can provide first-hand design solutions of ECR walls without performing rigorous numerical and experimental studies.

A Prediction Model for the Deformation of an Embedded Cantilever Retaining Wall in Sand

This paper proposes a prediction model based on the mobilizable strength design method with an equilibrium model to predict the deflection of an embedded cantilever retaining wall in sand. The variation in the location of the pivot point within the retaining wall and the sand dilation are considered. Based on the stress–strain relationships obtained by triaxial tests, the designer can determine a specific shear strain and corresponding mobilized earth pressure for the retaining wall to achieve a global equilibrium. Then, the wall deflection, including rotation and flexure, can be derived. The locations of the pivot points obtained by this method are compared with the results predicted by the minimization approach. Finally, the prediction precision is validated via centrifuge tests and numerical model data published in prior investigations.

Active Earth Pressure against Cantilever Retaining Walls with the Long Relief Shelf Rotating about the Bottom

Active Earth Pressure against Cantilever Retaining Walls with the Long Relief Shelf Rotating about the Bottom

Seismic Performance of Cantilever Retaining Walls with Tire Shreds as Compressible Inclusion

Seismic Performance of Cantilever Retaining Walls with Tire Shreds as Compressible Inclusion

Optimization of Reinforced Concrete Cantilever Retaining Wall using Particle Swarm Optimization

The design of structures depends on designer’s experience and generally, the designer proceeds with trial and error until he arrives at a design which satisfies prescribed limit states. This is especially true for reinforced concrete structures in which the structural configuration is decided first and then reinforcement requirements are determined, resulting in higher cost. Retaining walls involve a large number of variables and therefore have been far from optimization. However, since retaining walls comprise of 20-30 percent of the cost of highways in hilly regions, their optimization is critical to economy of the project. Particle Swarm Optimization (PSO) does not require the objective function to be linear or differentiable and hence is ideally suited for optimization of retaining walls. This study uses PSO as a tool for the optimizing a Cantilever RC Retaining Wall. The objective function consists of two parts - cost function and penalty term. A program and GUI was developed to implement PSO. A reduction in cost was achieved from 8% -17% depending on the height of retaining wall, while the optimization in weight varied from 9%-34%.

A Critical Review on Design of RCC Cantilever Retaining Wall

This paper provides an innermost and the dynamics role of the RCC Cantilever Retaining Wall in soil strata of different region especially on hilly and mountainous area of Himalayan range, analysis depending upon the previous research paper done by using different software. As we live on 21st century a result of population boom and new technology of different engineering properties developed day to day life. This is the major issue especially in the case of developing country where lot of earthwork is being carryout. Highway Bridges, flyover, Tunnel, Dams, Reservoirs and Cannels are constructed and developing rapidly in the big cities as well as in the countryside, making the study of RCC Cantilever Retaining Wall as an essential part of structural design process to Control flood, landslide of backfilling and natural Phenomena and for the economic purpose. The effect, on which the structures stands, especially in the highly seismic zones, the dynamic behavior of soil as well as retaining structure, should be well known by the designer. The effects of structures standing in a steep slope to each other are the main issue of cantilever retaining structure, as well as by-soil-structure interactions. In this paper, various methods of RCC Cantilever Retaining structure are carried out by various researchers in different software.

Design Optimization of Reinforced Concrete Cantilever Retaining Walls: A State‐of‐the‐Art Review

The booming growth of computational abilities in the 21st century has led to its assimilation and benefit in all horizons of engineering. For civil engineers, these advancements have led to groundbreaking technologies such as BIM, automation, and optimization. Unfortunately, even in an era of dwindling resources and dire need for sustainability, optimization has failed to attract implementation in practice. Despite an exponential growth as an area of research interest, the optimization of engineering structures such as reinforced concrete (RC) is still a complex task that requires multidisciplinary knowledge, hindering its practicability. Although past review papers have delved into this topic, they have only been able to cover the breadth of information available by covering broader aspects of optimization of structures. This study on the other hand aims to cover this topic in depth to uncover problem specific trends and issues, by focusing only on optimization of RC cantilever retaining walls. Although there is an abundance of research studies on this topic, there is an absence of any critical review to tie them up, and concurrently with its broader scope, it suffers the same lack of applicability in the field. The in‐depth review presents a summarization of all the online publications including research articles, conference papers, and theses to the best of authors’ knowledge on the topic of RC cantilever retaining wall optimization. Geographical trends, regional developments, and prominent journals have been identified. The design codes, problem formulation, objectives, constraints, variables, and their optimization techniques are tabulated for ease of understanding. Unique areas of development investigated by the different researchers have been highlighted. Lastly, comprehensive recommendations for future works have been detailed with a focus on improving its applicability and assimilation into the construction industry.

Dynamic Loads and Different Soil Characteristics Examination on Optimum Design of Cantilever Retaining Walls Utilizing Harmony Search Algorithm

Optimum the cantilever retaining wall design for different soils and dynamic earthquake effects is presented here. In the investigation of optimum wall design-based metaheuristic, the harmony search algorithm was considered for different design cases which include five soil and two earthquake characteristics. Earthquake characteristics of mild and severe were obtained regarding two locations which was selected from Turkey Earthquake Risk Map. For selected two locations and local soil classes, map spectral acceleration coefficients were utilized defined in Turkish Building Earthquake Code-2018. Sliding, overturning, and bearing capacity safety factors were taken as design constraints for checking stability criteria of the cantilever retaining wall which is given in Turkish Building Earthquake Code-2018. Since the cost-based wall weight of the optimization problem was taken as the objective function, obtained optimum wall dimensions which are discrete design variables were compared in terms of different design cases. It is seen that the wall dimensions increase in order to meet the design criteria in case of the earthquake load increases when the obtained optimum design by the optimization analyzes are examined. Another result obtained for the same earthquake zone is that the wall dimensions and therefore the cost mostly increase in weak quality soils.