Dams and Levees are engineered barriers designed to retain surface water. These structures are often required to limit water losses and pore-pressures through the barrier. This is often difficult to achieve because ideal natural materials are not always available at the site. As a result, advanced designs of dams and levees may include internal drains or barriers to trap or collect seepage water or to dissipate the hydraulic head that drives flow through the dam. Operation of the dam under changing water levels can further complicate the required design. Finally, it is imperative that the dam or levee be stable under construction, operation, and draw down conditions.
GeoStudio is a suite of software products that can be used to evaluate the performance of dams and levees with varying levels of complexity. The seepage, settlement, filling/draining, and stability performance of the structure can be simulated during the entire construction sequence. Either long-term (steady state) or detailed transient analyses can be done to consider time-dependent responses. Pore-water pressures and stresses can be included in an advanced stability analysis. The response of the structure to earthquake loading or ground freezing/thawing can also be investigated.
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Stability analysis during rapid drawdown is an important consideration in the design of embankment dams. Using SLOPE/W, stability during rapid drawdown can be analyzed in two approaches, namely the “effective strength” approach and the “staged undrained strength” approach. The purpose of this illustrative example is to show how to conduct a rapid drawdown analysis using the stage undrained strength approach.
GSZ: (1) (2) (3) (4)PDF
Stability analysis during rapid drawdown is an important consideration in the design of embankment dams. Using SLOPE/W, stability during rapid drawdown can be analyzed in two approaches; namely the “effective strength” approach and the “staged undrained strength” approach. The purpose of this example is to show how to conduct a rapid drawdown analysis using the effective stress approach.
The San Fernando earthquake occurred in California in 1971. The earthquake created a liquefaction failure at the Lower San Fernando Dam and Reservoir. This analysis demonstrates the advantages of using QUAKE/W with other GeoStudio products to analyze the multiple issues that arose with this case.
There are several different ways that pore-water pressures can be defined within SLOPE/W. For the simplest scenarios, a piezometric line can be drawn with hydrostatic conditions assumed both above and below the piezometric line. For more complex pore-water pressure situations, you can integrate results from a SEEP/W finite element analysis where the total heads at each node are computed and used by SLOPE/W. Another option is to specify different pore-water pressure heads at discrete points within the SLOPE/W profile using the pressure head spatial function option.
SLOPE/W is the leading slope stability software for computing the factor of safety of earth and rock slopes. SLOPE/W can effectively analyze both simple and complex problems for a variety of slip surface shapes, pore-water pressure conditions, soil properties, analysis methods and loading conditions.
SEEP/W analyzes groundwater flow within porous materials such as soil and rock. Its formulation enables analyses ranging from simple saturated steady-state problems to sophisticated saturated/unsaturated time-dependent problems.
SIGMA/W performs stress and deformation analyses of geotechnical, civil and mining works. It can perform a simple linear elastic deformation analysis or a highly sophisticated soil-structure interaction analysis with non-linear material models and coupling to seepage analysis.
QUAKE/W enables dynamic analysis of earth structures subjected to earthquake shaking, or point dynamic forces from a blast or a sudden impact load. It determines the motion and excess pore-water pressures that arise due to shaking.
CTRAN/W models the movement of contaminants through porous materials such as soil and rock. CTRAN/W can be used to model simple diffusion-dominated systems through to complex advection-dispersion systems with first-order reactions.