Unsaturated slope stability and seepage analysis of a dam. This paper presents the results of seepage and stability analyses of the considered earth dam using finite element method. The porewater pressure, whether positive or negative, is. It involves identifying the source of the leak and designing a solution to rectify the problem. Characterization and analysis of rainfall was required to evaluate the water level, net infiltration, and seepage within dam i. Potential multiple seepage faces integrating seepw and slopew effect of suction on stability 3 geometry and boundary conditions the seepage portion of the analysis is illustrated in figure 1.
Flow quantity is a key parameter in quantifying seepage losses from a reservoir or indentifying a potential water supply for domestic or industrial use. The seepage analysis is divided into two categories viz. What is difference between permeability and seepage. The value of the coefficient of permeability k depends on the. Conducting seepage analysis is a critical step to the success of geotechnical engineering projects.
References this publication is adapted from the unified facilities criteria of the united states government which are. The flow of water through soils, called seepage, occurs when there is a difference in the water level energy on the two sides of a structure such as a dam or a sheet. Design equations, criteria, and examples are discussed in the technical literature. Permeability and seepage the coefficient of permeability or permeability in soil mechanics is a measure of how easily a fluid water can flow through a porous medium soil. Considerations relating to seepage analysis prepare cross sections to scale showing the boundaries of the. Chapter 6 soil seepage and drainage pile buck magazine. Ahmed soil mechanics notes chapter five permeability and seepage through soil. Finite element free surface seepage analysis without mesh. Finite element free surface seepage analysis 15 in equation 2 p is the fluid pressure, y is the unit weight of fluid and z is the elevation at the point under consideration. Engr 3150 principles of soil mechanics permeability and seepage chapter 7.
Determination of seepage and analysis of earth dams case. Also, an equation has been presented to calculate the seepage from the body of embankment dam with oblique core which, the passing discharge rate is a function of core angle. To estimate the phreatic surface within an embankment. A variety of approaches have historically been utilized to per. Seepage depends on several factors, including permeability of the soil and the pressure gradient, essentially the combination of forces acting on water through gravity and other factors. Concrete gravity and arch dams are subject to seepage through the foundation and abutments. Indian institute of technology, kanpur 1 module 2 lecture 9 permeability and seepage 5 topics 1. Pdf seepage analysis through earthfill dams having.
It is defined as the property of a porous material which permits the passage or seepage of water or other fluids through its interconnecting voids. Finite element analysis of partially saturated seepage. The permeability coefficient is used to compute the quantity and rate of water flow through soils in drainage and seepage analysis. For the love of physics walter lewin may 16, 2011 duration. General pressure, head, and total head darcys law measurement of permeability general. Seepage is the water reservoir finding its way downstream through pervious material or through imperfections in the dam. If you continue browsing the site, you agree to the use of cookies on this website. An introduction to seepage, slope and settlement of levees. Analysis of seepage with nonlinear permeability using. Property of a soil which permits the flow of water permeability is defined as the property of a porous material which permits the passage or seepage. An analytical approach for levee underseepage analysis. The role of drainage system is also vital as it shifts the phreatic surface ensuring the safety of downstream toe. Further analysis of hydraulic conductivity in granular soils based on.
Seepage analyses were performed for the sections shown in table a1. Permeability and seepage through soil slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Site information specifically relating to permeability of materials and seepage flow. In general, the slope is comprised of multiple layers with a finer, lower permeability layer located half way up the slope face. Ahmed soil mechanics notes chapter five permeability. Seepage, in soil engineering, movement of water in soils, often a critical problem in building foundations. Seepage is phenomenon of movement of fluid through permeable medium for example water on one side of dam comes out from the other side through seepage in ground which we control by providing sheet piles. The seepage velocity is related to the value of coefficient of permeability by the equation. Hydraulic conductivity is another term used for permeability, often in environmental engineering literature. Seepage analysis water flow through soil subsurface. Seepage analyses are carried out for the following reasons. Seepw generated porewater pressures in slopew stability. All earth and rockfill dams are subject to seepage through the embankment, foundation, and abutments.
Introduction the paper presents stability and seepage analysis performed in unsaturated regime to take care of the infiltration through the dam. Reynolds number there remains now the question of the determination of. In the context of the discussions and examples in this document and in using the seepw software, the term seepage is used to describe all movement of water. In the factual definition, piping is the forming of an open channel from entry point to exit point. Pressure or flow boundary conditions are then applied to the model to define the initial conditions for seepage analyses. Seepage and stability analyses of earth dam using finite. Seepage, deformation, and stability analysis of sandy and clay. The final soil parameters used in the seepage analysis of the stadium conglomerate at 2 percent wet of optimum are summarized below. Stochastic analysis of seepage through natural alluvial.
Generally, the following items are required to evaluate site conditions for making seepage analysis. Darcys law, permeability, factors affecting permeability, determination of permeability laboratory and field methods, permeability of stratified soil deposits. Permeability and seepage fundamentals of soil mechanics for. Permeability and seepage fundamentals of soil mechanics. Seepage control is necessary to prevent excessive uplift pressures, sloughing. Seepage analysis is primarily concerned with water leaking from a contained source, generally a tank, a pool, a dam or similar structures, into the surrounding soil. In a porous environment analysis, with use of the obtained data and specification f o different boundary conditions effectively been used different layers of the dam and seepage analysis with the figure 2. Let b and l are the width and length of the field respectively. C 2 k s c 2 is a constant that may be used to differentiate between soil type and severity of the seepage condition, and. An equation that has been proposed for absolute permeability k of sandy soils is. Permeability of all materials in the condition under which they will exist after the structure has been constructed.
Permeability can vary over a wide range, depending on soil structure and composition, making possible. The seepage rate q through the dam can be computed from the flownet. Chapter pdf available february 2018 with 11,417 reads. Seepage pressure, quick condition, laplace equation for two dimensional. Subspecialties hydraulic fracture permeability testing seepage analyses. In seepage problems the velocity of flow is very small and the velocity head is. Seepage modeling with seepw geoslope international. Keywords anisotropy, consolidation, nonlinearity, seepage. Laboratory tests are appropriate for undisturbed samples of finegrained materials and compacted materials in dams, filters, or drainage structures.
Critical hydraulic gradient and quicksand unconfined flow nets and approximations in conventional formulation. Seepage analysis through earthfill dams having random fields m. Site information specifically relating to permeability of materials and seepage flow must be collected for each site. For crossplane permeability, the capacity of the geotextile must meet or exceed the crossplane permeability k s of the soil, where 6. Lecture 9 numerical analysis of seepage notes edurev. A column of water in equilibrium with the pore pressure at b would rise to a. Let b be at a height z above some arbitrary datum level aa in fig. Consulting services incorporated csi, a lexington, kentucky based engineering consulting firm, is wellequipped and experienced to perform this analysis.
Kaerkheh dam is made up in mesh within the aid of software some meaningful tables and figures are. Pdf engr 3150 principles of soil mechanics permeability and. Introduction freesurface seepage problems have been attracting interests of many engineers and mathematicians due to the strong nonlinearity as well as the importance in designing the. Excessive seepage leads to dam safety issues, if not treated carefully. This type of analysis also provides additional critical information, such as an estimate of the quantity of seepage that passes through the levee foundation over time. Ppt permeability and seepage ronilo parina academia. Purpose of seepage analysis dams must be designed and maintained to safely control seepage. Sivakugan 2005 1 chapter 7 permeability and seepage 7. Porepressures associated with groundwater flow are of particular concern in geotechnical engineering. Introduction bernoullis equation darcys law laboratory determination of permeability permeability of stratified soils seepage velocity stresses in s. View dam seepage analysis research papers on academia.
Page 1 nptel advanced geotechnical engineering dept. Consider a point b in a mass of saturated uniform porous soil. Geometry of the structure and the related upstream and down stream water levels during the planned operation. Definition, darcys law and tests definition of permeability. The analysis of seepage flow through a dam, a ditch for exca. An analysis of system flexibility and its effect on time lag in pore water pressure measurements. Groundwater, seepage and permeability geotechnical and. The mechanics of seepage analysis nrcs irrigation toolbox. This includes information for locating boundaries between materials of different permeability. Permeability and seepage applied soil mechanics wiley. Permeability or hydraulic conductivity values horizontal and vertical are then assigned to the layers as soil type designations.
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