Relief Shelves 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

Impact of Relief Shelves on Earth Pressure Reduction Under At-Rest Conditions: Physical Modeling Tests

Impact of Relief Shelves on Earth Pressure Reduction Under At-Rest Conditions: Physical Modeling Tests

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.

Numerical Evaluation of the Relief Shelves for Lateral Thrust Reduction on Wall under At-Rest Condition

Numerical Evaluation of the Relief Shelves for Lateral Thrust Reduction on Wall under At-Rest Condition

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

Active earth pressure on retaining wall with a relief shelf: a novel analytical method

Active earth pressure on retaining wall with a relief shelf: a novel analytical method

Limit analysis of the retaining wall with relief shelves under static surcharge loading using FEM

Limit analysis of the retaining wall with relief shelves under static surcharge loading using FEM

Behavior of Rigid Retaining Walls with Relief Shelves: An Analytical Approach

Behavior of Rigid Retaining Walls with Relief Shelves: An Analytical Approach

Facies architecture and depositional model for a fine‐grained hybrid‐energy delta: An example from the Upper Cambrian to Lower Ordovician Barik Formation, Central Oman

Recognizing ancient deltas' depositional architecture is challenging due to the complex interplay of the fluvial, waves, and tidal processes. The integration of field‐based sedimentological and trace fossils studies of the Late Cambrian‐Early Ordovician Barik Formation in Central Oman allowed better identification of different lithofacies architectures and depositional process signatures. The Barik Formation is a major tight‐gas reservoir in the Oman Sedimentary Basins, where it is over 800‐m thick. The only outcrop analogue is in the Qarn Mahatta Humaid area, where ca. 50‐m thickness of the formation is exposed and extends laterally over 5 km. This study revealed the presence of four lithofacies associations, including (a) mouth bar/shoreface, (b) tidal flat, (c) tidal channel, and (d) delta distributary channels using 12 logged sections. The depositional features identified in the field include tidal, wave/storm, and fluvial. The tidal signatures are represented by mud‐drapes, large‐scale reactivation surfaces, sigmoidal cross‐bedding, and climbing and flaser bedding, predominantly in the mixed mud‐sand tidal flats of the lower delta plain and delta distributary channels of the upper to lower delta plains. The wave/storm signatures are represented by wave ripples and small‐scale hummocky cross‐stratification in the mouth bar/shoreface of the delta front platform. The fluvial and subaerial signatures are represented by the occurrence of the scour surfaces with lag deposits of channel‐fill and the development of desiccation mud‐cracks. The Barik Formation delta sandstones form amalgamated sheet‐like bodies prograding to the north‐northeast and deposited along a ramp‐type low relief basin. This prograding delta represents a highstand system tract. This study presents an example of the ancient fine‐grained hybrid‐energy prograding delta, where fluvial processes operated beside the tidal and wave/storm processes over a broad and low relief shelf in a vegetation‐free system.

Rigid diaphragm wall with a relief shelf to mitigate the deformations of soil and shallow foundations subjected to normal faulting

Previous studies developed several types of weak and soft walls to deviate reverse fault ruptures and to absorb the compressional soil deformation. However, different strategies are required to address the extensional soil deformation caused by normal faulting. This study proposes a rigid diaphragm wall with a relief shelf (RDWRS) to mitigate soil and shallow foundation deformations in normal fault. The relief shelf is applied to keep the stability of the diaphragm wall and to protect the shallow foundation on the ground surface. Numerical modeling is performed to investigate the diaphragm wall-normal fault interaction mechanisms and the effects of RDWRS on deformation mitigation of shallow foundations. The RDWRS shows promising effects concerning the mitigation of soil and shallow foundation deformations. The protection effects depend on soil depth, foundation width, foundation location, surcharge pressure, wall depth relative to the rupture, the width of the relief shelf, and the distance between the wall and the foundation. As this paper presents the results of numerical modeling, experimental studies are suggested for future studies. Besides, the economy of the RDWRS should be comprehensively considered when applying this method.

Optimal Design of Cantilever Retaining Wall Using Relief Shelve: A Review

The sectional dimensions of retaining wallessentially depends on the active lateral earth pressure acting on it. Many researchers have struggledon researches to minimize the effective lateral pressure and to adopt the optimized and economical design for retaining walls. Provision of relief shelves to retaining walls reduces the lateral earth pressure, this type of retaining wall is considered as a special type of retaining wall. For high cantilever wall, there will maximum bending moments and shear force for which providing relief shelves will be beneficial.This paper conducts thorough review of analysis and design of cantilever retaining wall with and without relief shelves, study the effect of provisions of relief shelf as aplatform in cantilever retaining wall. The arrangement of the reinforcement at the critical junction where relief shelve platform connecting to the stem wall is to be analyzed and studied to feasibility to install actual on site. Keywords: Cantilever retaining wall, relive shelve, lateral earth pressure, economical design, finite element method Cite this Article: Ajinkya S. Saraf, Ajay G.Dahake. Optimal Design of Cantilever Retaining Wall Using Relief Shelve: A Review. International Journal of Structural Engineering and Analysis . 2020; 6(1): 29–39p.

Investigation of active earth pressures and failure mechanism of retaining walls with a relief shelf

Various studies of retaining walls with relief shelves tend to rely on the proposition of reducing soil pressures behind the wall, according to the location and the width of relief shelf. The previous numerical studies did not predict the optimum reduction rate of earth pressure and the shape of failure mechanism. The finite-difference code fast Lagrangian analysis of continua is used to evaluate the active earth pressure behind a retaining wall with one relief shelf placed at different levels with a variable width. The soil behind the wall is modelled by an elastoplastic constitutive model with a Mohr–Coulomb yield criterion. The effects of soil non-associativity as well as the interface of soil–wall and relief shelf–soil are investigated. The reduction of earth pressure is estimated by the rate R, defined as the ratio of the reduced active thrust to the total active thrust of a wall without a relief shelf. The rate R is evaluated numerically and by using Klein’s solution. The obtained results enable determination of the appropriate position and width of the relief shelf to evaluate the optimum values of R.

Performance of a Rigid Retaining Wall with Relief Shelves

AbstractEarth pressure on a retaining wall decides the sectional dimensions of the wall, and there have been several attempts in the literature to reduce the earth pressures on the retaining walls,...

Retaining walls with relief shelves

Cantilever retaining wall with pressure relief shelves is considered as a special type of retaining wall. The concept of providing pressure relief shelves on the backfill side of a retaining wall reduces the total earth pressure on the wall, which results in a reduced thickness of the wall and ultimately in an economic design of a cantilever wall. A limited number of solutions and measurements can be found for this type of wall in the literature. The shapes of the measured earth pressure distributions differ among studies because the model scales were different; for example, the wall during one measurement was permitted to move but was not permitted to move in the other measurements. This paper presents a Finite Element analysis of this type of wall using PLAXIS2D-AE.01. The reduced total active earth pressure due to the provisioning of shelves is depicted. It was found that the shelves had a significant effect on the resulting earth pressure distribution. The distribution approximately followed the distribution of the solution by Klein (Calculation of retaining walls (in Russian). Vysshaya Shkola, Moscow, 2014). It also followed the shape of the measurements of Yakovlev (Experimental investigation of earth pressure on walls with two platforms in the case of breaking loads relieving on the backfill. Odessa Institute of Naval Engineers, pp 7–9, 1974). A parametric study was conducted to enable a discussion of the effects of the number of shelves, shelf rigidity, and shelf position on the resulting distribution of the lateral earth pressure, wall top movement, and acting maximum flexural moment of the wall. For high retaining walls and for some repair systems for constructed walls that have problems with stability, it is recommended to provide the cantilever wall with a shelf at a third of the wall height from the top of the wall or more shelves at different levels. Suggested updates are provided to enhance the manual solution of Klein in the calculation of the acting maximum bending moment of the wall.

Investigation of failure of a rigid retaining wall with relief shelves

Investigation of failure of a rigid retaining wall with relief shelves