Dynamic pressures on rigid cantilever walls retaining. On the basis of the limit equilibrium approach and limit state analysis, this paper presents a solution to compute the seismic earth pressure on the back of a retaining wall. As can be seen in figure 2b, the computed dynamic stress incr ement is zero at the base and maximum at the top of the backfill with the recomme nded point of applica tion of the resulting force at 0. Limit equilibrium analysis imposes a pseudostatic inertial.

The measured distributions of total and dynamic earth pressures, as shown in figures 7 and 8, present that the distributions are nonlinear along the wall height and the amplitude of the earth pressures are proportional to the excited seismic peak accelerations 21, 22. For instance a retaining wall can be used to retain fill along a. The distribution of seismic earth pressures on rigid retaining walls is an important task in design. A new approach for estimating the seismic soil pressure on retaining walls s. The determination of dynamic seismic lateral earth pressures on foundation walls and retaining walls supporting more than 6 feet 1.

Pdf proposed dynamic soil pressure diagram on rigid walls. Earth pressure and retaining wall basics for nongeotechnical engineers richard p. The problem of analyzing seismic earth pressures on retaining structures is complicated by the fact that it involves a dynamic soilstructure interaction that does not lend itself to easy simplification using limit equilibrium. The upper surfaces of the soil layer and the wall are assumed to be free. The available methods of dynamic seismic response of retaining walls can be grouped into three categories 1, 2 depending mainly on the degree of modeling elaboration of the soil material. Thus, more research is required in order to clarify the seismic effects on a buried structure. The problem of analyzing seismic earth pressures on retaining structures is complicated by the fact that it involves a dynamic soil structure interaction that does not lend itself to easy simplification using limit equilibrium. A critical evaluation is made of dynamic pressures and the associated forces induced by ground shaking on a rigid, straight, vertical wall retaining a semi. Pseudostatic lateral earth pressures on brokenback.

Dynamic soil pressures on rigid vertical walls, earthquake. Lateral earth pressures and retaining walls assistant prof. Horizontal earth pressures on rigid vertical walls in liquefied soils with a level ground surface have extensively been studied by many researchers. Kinematic ssi solutions are often formulated for uniform soil conditions, but the shear modulus of most soils is known to increase with mean effective stress, and therefore with depth. A critical evaluation is made of the dynamic pressures and the associated forces induced by ground shaking on a rigid, straight, vertical wall retaining a semiinfinite, uniform viscoelastic layer of constant thickness. Distribution of seismic earth pressures on rigid retaining walls.

The dynamic active earth pressure on retaining structures due to seismic loading is commonly obtained by using the modified coulombs approach which is known as the mononobeokabe method. The lateral movements of the walls are kept below 1% to 2% of the depth of the excavation. Dynamic soil pressures on rigid vertical walls wiley online library. Liquefied soil pressures on vertical walls with adjacent. Static and dynamic active earth pressure springerlink. Earthquake engineering and structural dynamics 23 3. Several researchers have used elastic wave theory to derive seismic soil pressure against a rigid wall. A soil pressure coefficient, k0e, has been introduced to represent the total static and seismic pressures on a rigid or nonyielding wall. Dynamic pressures on a pair of rigid walls retaining. Seismic earth pressures exerted on rigid walls by vertically. Seismic lateral pressures for design of rigid walls guoxi wu and w. Dynamic soil pressures on rigid vertical walls dynamic soil pressures on rigid vertical walls veletsos, a. In the present work the dynamic wall pressures and the associated forces on a pair of rigid walls experiencing base rotation and retaining a uniform, fully. Coefficient k is the ratio of lateral to vertical effective stress at the wallbackfill interface.

Harmonic response of a rigid wall retaining poroelastic soil. Dynamic active earth pressure on retaining structures. In the present work the dynamic wall pressures and the associated forces on a pair of rigid walls experiencing base rotation and retaining a uniform. Beskos department of civil engineering, university of patras, greece abstract the problem of the determination of the dynamic pressures and the associated forces on a rigid, vertical cantilever wall retaining a semiinfinite, uniform, fully. In this paper, a simple nite element model for seismic analysis of retaining walls is introduced. Limit equilibrium analysis imposes a pseudostatic inertial force to a soil. A critical evaluation is made of dynamic pressures and the associated forces induced by ground shaking on a rigid, straight, vertical wall retaining a semi infinite. Recognizing the limitation of the mo method, a simplified method was recently developed to predict lateral seismic soil pressure for building walls. This method has generally been used for cohesionless soils only. The base of the soil layer is excited by a harmonic excitation to simulate earthquake conditions.

Design charts for seismic pressures against rigid walls subjected to horizontal earthquake shaking are presented for both uniform and nonuniform backfills. An analytical model is presented for evaluating the dynamic increment of lateral earth pressure on perfectly rigid unyielding walls. In this paper, a series of centrifuge tests was conducted to investigate the effects of embankments resting on ground surfaces on the pressure on the rigid vertical walls. Yener ozkan august 2003, 101 pages lateral pressures on nonyielding walls due to surface strip loads were investigated considering the nonlinear stressstrain behaviour of the soil by finite. Seismic earth pressures on retaining structures and basement. They simplified the problem by assuming zero vertical displacement v 0in the soil mass. In order to design soilretaining structures such as retaining walls2 and sheet pile walls 3, it is necessary to determine the magnitude of the lateral pressures to which the structure is subjected.

Seismic earth pressures on rigid and flexible retaining walls. The dynamic excess pore water pressures due to the vertical and horizontal components of earthquakes decrease slightly with the decrease in the degree of saturation from 0. The method is focused on the building walls rather than retaining walls and specifically considers the dynamic soil properties and frequency content of the design motion in its formulation. A complete study to determine the seismic active earth pressure behind a rigid retaining wall by pseudo dynamic approach has been carried out by deepankar.

Pdf using finite element nonlinear analysis, the dynamic soil pressure on perimeter. Dynamic response of soil pressure on retaining wall. We examine the influence of vertical heterogeneity of shear modulus on kinematic ssi for rigid walls. Dynamic earth pressure profile on rigid walls, after matthewson et al. Matsuo and ohara 1960 obtained an approximate elastic solution using a twodimensional analytical model. Evaluation of dynamic soil pressures acting on rigid. Hysteretic damping in the soil skeleton may also be present.

Seismic earth pressures on retaining structures and. The dynamic response of a watersaturated linear poroelastic soil layer over bedrock retained by a pair of rigid cantilever walls to a horizontal seismic excitation is obtained analytically. Feb 01, 2006 liquefied soil pressures on vertical walls with adjacent embankments liquefied soil pressures on vertical walls with adjacent embankments okamura, m ishihara, m tamura, k. Dynamic soil pressures asce 498 wood 1973 dynamic earth pressures myths, realities and practical ways for design. Experimental results on earth pressures on rigid wall under. Numerically, eqd is equal to the horizontal seismic coefficient, k. Seismic lateral pressures for design of rigid walls wutec. The lateral pressure behind a wall will vary depending on whether the wall is going away from soil or towards soil. In this approach, the retaining wall is considered as a vertical flexible beam and the soil is assumed to be a linearelastic material with hysteretic damping. Horizontal earth pressures on rigid vertical walls in liquefied soils have extensively been studied by many researchers for the level ground surface condition.

Weber course content content section 1 retaining walls are structures that support backfill and allow for a change of grade. Static behaviour of retaining walls soil pressure distribution. During earthquake ground shaking earth pressures on retaining structures can cyclically increase and decrease as a result of inertial forces applied to the walls and kinematic interactions between the stiff wall elements and surrounding soil. Dynamic soil pressures on rigid vertical walls technical. Dynamic excess pore water pressures by dynamic soil. Design of earth retaining structures for dynamic loads, prof h. Seismic active earth pressure behind retaining wall.

Dynamic pressures on rigid cantilever walls retaining poroelastic soil media. This work deals with the evaluation of the dynamic pressures and the associated forces on a pair of rigid vertical cantilever walls retaining a uniform, fully saturated poroelastic layer of soil. Dynamic poroelastic soil pressures on a pair of rigid. Conventional methods either use pseudostatic approaches of analysis even for dynamic cases or a simple singledegree of freedom model for the retaining wallsoil system. A summary is presented of recently contributed simple approximate solutions for the dynamic pressures and the associated forces induced by ground shaking on rigid vertical walls. Evaluation of dynamic soil pressures acting on rigid culverts. The effective stress is the intergranular stress calculated by subtracting the pore pressure from the total stress as described in soil mechanics. Solutions are based on a simplified model of soil response which. This paper examines the dynamic soil pressures and associ.

Keywords retaining walls, rigid walls, dynamic pressure, soil structure interaction. Dynamic earth pressure myths, realities and practical. Dynamic soil pressures on rigid vertical walls veletsos. Dynamic earth pressure myths, realities and practical ways for design carlos coronado and javeed munshi. Dynamic active earth pressure on retaining structures 723 figure 1. The gravity wall retaining walls are thick and stiff enough that they do not bend. Seismic earth pressures of retaining wall from large shaking. The model incorporates nonlinearity in the behavior of near wall soil, wall exibility and elastic free eld soil response. Arching effect for confined backfill in tall rigid walls. Limit equilibrium analysis imposes a pseudostatic inertial force to a soil wedge behind the wall the mechanism behind the widelyused. Dynamic soil pressures on vertical walls scholars mine.

This solution is an extension of a previously published analytical model analyzing response of underground structures to vertically propagating waves. Nevertheless, such simplification is the essence of the most commonly used limit equilibrium method. The upper portions of the vertical side walls of the excavation are supported in stages as the excavation is deepened. The effects of both harmonic and earthquakeinduced excitations are. Due to the complexity of the soilwall interaction, numerical techniques have recently been adopted to compute the seismic earth pressure against a retaining wall alhomoud and whitman, 1994. Seismic earth pressure exerted on rigid walls by vertically. For the first time wood, et al 1 developed an equivalent static elastic solution for the dynamic soil pressure on nonyielding walls, using linear elastic finite element method 1. The journal aims to encourage and enhance the role of mechanics and other disciplines as they relate to earthquake engineering by providing opportunities for the publication of the work of applied mathematicians, engineers and other applied scientists involved in solving problems closely related to the field of earthquake engineering and geotechnical earthquake engineering. The lateral earth pressure is important because it affects the consolidation behavior and strength of the soil and because it is considered in the design of geotechnical engineering structures such as retaining walls, basements, tunnels, deep foundations and braced excavations.

Seismic earth pressures a technical note oasys software. It has been recognized that time histories of earth pressures during an earthquake consist of the monotonic increase and the dynamic fluctuations. Gazetasa aschool of civil engineering, national technical university, athens, greece bmueser rutledge consulting engineers, new york, usa accepted 11 november 2004 abstract while limitingequilibrium mononobeokabe type solutions are still widely used in designing rigid. For intermediate cases, the dynamic earth pressures are somewhere between the maximum and minimum value see ref. Synopsis an effective numerical method for the dynamic analysis of soil pressures on retaining walls has been proposed. Dynamic response of underground structures in sand. A complete study to determine the seismic active earth pressure behind a rigid retaining wall by pseudodynamic approach has been carried out by deepankar. A new approach for estimating the seismic soil pressure on. Cantilever reinforcement reinforcement counterfort 4.

Seismic lateral pressures for design of rigid walls. For instance a retaining wall can be used to retain fill along a slope or it can be used to. A general solution for the determination of total i. Dynamic soil pressures on rigid cylindrical vaults. The walls of the excavation are pervious enough so that water pressure does not build up behind them. Counterfort strectcher headers filled with soil face of wall 5. The dynamic earth pressures are comparatively small for pga less than 0. For the analysis and design of retaining walls in earthquakeprone zones, accurate estimation of dynamic earth pressures is very important. Table 2 variations of the dynamic excess pore water pressures. Gravity retaining walls fig 1 a are the oldest and simplest type of retaining walls.

Soil dynamics and earthquake engineering journal elsevier. Conventional methods either use pseudostatic approaches of analysis even for dynamic cases or a simple singledegree of freedom model for the retaining wall soil system. Vertical pressures for roller compacted concrete wall rcc lateral soil pressures. This result was expected as pressures are a function of soil displacement and minimal displacements are present in the bedrock layer i. Liquefied soil pressures on vertical walls with adjacent embankments liquefied soil pressures on vertical walls with adjacent embankments okamura, m ishihara, m tamura, k. Berrak teymur retaining walls are usually built to hold back soil mass 1. The coefficient of lateral earth pressure, k, is defined as the ratio of the horizontal effective stress.

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