Seepage Analysis - Revision history

Grichards@gfnet.com at 19:48, 27 August 2024

2024-08-27T19:48:01Z

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	*“If steady-state seepage stability is highly dependent on the success of internal drainage features to control the phreatic surface, check stability assuming partially functioning or plugged drainage systems.”<ref name="NRCS"></ref>		*“If steady-state seepage stability is highly dependent on the success of internal drainage features to control the phreatic surface, check stability assuming partially functioning or plugged drainage systems.”<ref name="NRCS"></ref>
	*When possible, monitoring data from [[piezometers]] can be used to calibrate seepage models.		*When possible, monitoring data from [[piezometers]] can be used to calibrate seepage models.

			A critical aspect of any [[engineering]] analysis is communication. There are a variety of seepage modeling approaches and methodologies, and it is important to owners, consultants, and regulators that clear communication is integrated in the process. General guidance and recommendations regarding both pre- and post-modeling communication are provided on this page: [[Modeling Communication]]. Items specific to seepage analysis that should be considered in advance of any modeling effort are summarized here: [[Pre-Modeling Communication: Seepage Model Considerations]].

	==Best Practices Resources==		==Best Practices Resources==

Mpollei@gfnet.com at 15:12, 11 July 2023

2023-07-11T15:12:43Z

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	==Best Practices Resources==		==Best Practices Resources==
	{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS~~, 2019~~]]		{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS]]
	{{Document Icon}} [[Seepage Analysis and Control for Dams (EM 1110-2-1901) \| Seepage Analysis and Control for Dams (EM 1110-2-1901), USACE~~, 1993~~]]		{{Document Icon}} [[Seepage Analysis and Control for Dams (EM 1110-2-1901) \| Seepage Analysis and Control for Dams (EM 1110-2-1901), USACE]]
	{{Document Icon}} [[Design Standards No. 13: Embankment Dams (Ch. 8: Seepage) \| Design Standards No. 13: Embankment Dams (Ch. 8: Seepage), USBR~~, 2014~~]]		{{Document Icon}} [[Design Standards No. 13: Embankment Dams (Ch. 8: Seepage) \| Design Standards No. 13: Embankment Dams (Ch. 8: Seepage), USBR]]

	==Trainings==		==Trainings==

Grichards at 17:34, 16 March 2023

2023-03-16T17:34:51Z

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	==Guidance for Performing Seepage Analysis==		==Guidance for Performing Seepage Analysis==
	The key inputs to any seepage analysis are:		The key inputs to any seepage analysis are:
	*[[Soil/Rock Permeability Characterization\|Horizontal and ~~Vertical~~ permeability of the soil or rock]]		*[[Soil/Rock Permeability Characterization\|Horizontal and vertical permeability of the soil or rock]]
	*[[Seepage Analysis Boundary Conditions]]		*[[Seepage Analysis Boundary Conditions\|Boundary conditions]]

	Other general guidance when completing a seepage analysis includes:		Other general guidance when completing a seepage analysis includes:

Grichards at 17:34, 16 March 2023

2023-03-16T17:34:10Z

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	==Guidance for Performing Seepage Analysis==		==Guidance for Performing Seepage Analysis==
	~~"Existing embankments may not have achieved steady-state conditions. Thus, use the calculated long-term high-level steady-state~~ seepage ~~condition for both new~~ and ~~existing embankments. For existing embankments, compare~~ the ~~computed phreatic surface with field performance and field measurements, when available, to assure that the computed phreatic surface meets~~ or ~~exceeds that which has occurred over the life of the structure.”<ref name="NRCS"></ref>~~		The key inputs to any seepage analysis are:
			*[[Soil/Rock Permeability Characterization\|Horizontal and Vertical permeability of the soil or rock]]
			*[[Seepage Analysis Boundary Conditions]]

	“Include a separate foundation phreatic surface as appropriate at sites with limited foundation seepage [[cutoff]], particularly in sites with confined seepage that results in uplift at the downstream toe.”<ref name="NRCS"></ref>		Other general guidance when completing a seepage analysis includes:
			*"Existing embankments may not have achieved steady-state conditions. Thus, use the calculated long-term high-level steady-state seepage condition for both new and existing embankments. For existing embankments, compare the computed phreatic surface with field performance and field measurements, when available, to assure that the computed phreatic surface meets or exceeds that which has occurred over the life of the structure.”<ref name="NRCS"></ref>
	“If steady-state seepage stability is highly dependent on the success of internal drainage features to control the phreatic surface, check stability assuming partially functioning or plugged drainage systems.”<ref name="NRCS"></ref>		*“Include a separate foundation phreatic surface as appropriate at sites with limited foundation seepage [[cutoff]], particularly in sites with confined seepage that results in uplift at the downstream toe.”<ref name="NRCS"></ref>
			*“If steady-state seepage stability is highly dependent on the success of internal drainage features to control the phreatic surface, check stability assuming partially functioning or plugged drainage systems.”<ref name="NRCS"></ref>
	When possible, monitoring data from [[piezometers]] can be used to calibrate seepage models.		*When possible, monitoring data from [[piezometers]] can be used to calibrate seepage models.

	==Best Practices Resources==		==Best Practices Resources==

Grichards at 17:25, 16 March 2023

2023-03-16T17:25:26Z

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	The purposes of completing a seepage analysis for a dam include:		The purposes of completing a seepage analysis for a dam include:
	*Ensuring that seepage does not exit on the face of the dam. This may indicate a potential for internal erosion from an unfiltered outlet.		*Ensuring that seepage does not exit on the face of the dam. This may indicate a potential for internal erosion from an unfiltered outlet.
	*Estimating the phreatic surface for various loading conditions to support slope stability analysis.		*Estimating the phreatic surface for various [[Loading Conditions\|loading conditions]] to support [[Slope Stability\|slope stability]] analysis.
	*Estimating seepage quantity to support drain design.		*Estimating seepage quantity to support drain design.

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	*"'''Numerical Methods''' – Use computer based numerical methods to analyze seepage in cases where graphical solutions are not practical, there is complex stratigraphy or there is a need to account for saturated and unsaturated or transient flow. Designers can use these methods to estimate seepage quantities and pore water pressures an evaluate the exit gradient for embankments and foundations, as well as uplift pressures acting on appurtenant concrete structures or soil blankets.”<ref name="NRCS"></ref>		*"'''Numerical Methods''' – Use computer based numerical methods to analyze seepage in cases where graphical solutions are not practical, there is complex stratigraphy or there is a need to account for saturated and unsaturated or transient flow. Designers can use these methods to estimate seepage quantities and pore water pressures an evaluate the exit gradient for embankments and foundations, as well as uplift pressures acting on appurtenant concrete structures or soil blankets.”<ref name="NRCS"></ref>

	==Guidance for Seepage Analysis==		==Guidance for Performing Seepage Analysis==
	"Existing embankments may not have achieved steady-state conditions. Thus, use the calculated long-term high-level steady-state seepage condition for both new and existing embankments. For existing embankments, compare the computed phreatic surface with field performance and field measurements, when available, to assure that the computed phreatic surface meets or exceeds that which has occurred over the life of the structure.”<ref name="NRCS"></ref>		"Existing embankments may not have achieved steady-state conditions. Thus, use the calculated long-term high-level steady-state seepage condition for both new and existing embankments. For existing embankments, compare the computed phreatic surface with field performance and field measurements, when available, to assure that the computed phreatic surface meets or exceeds that which has occurred over the life of the structure.”<ref name="NRCS"></ref>

Grichards at 17:25, 16 March 2023

2023-03-16T17:25:08Z

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	[[Category:Seepage Analysis and Filter Design]]		[[Category:Seepage Analysis and Filter Design]]
	----		----
	“Evaluate the effects of seepage for all dams. The evaluation must address all potential embankment and foundation seepage related failure modes, including the potential for internal erosion, erosive flow along defects, internal stability, and uplift pressures to damage the embankment, its foundation, and appurtenant structures. The evaluation should be commensurate with the complexity, function, and [[Hazard Potential Classification\|hazard potential classification]] of the structure. Seepage control and management must be adequate to accomplish the intended reservoir function, provide a safety operating structure, and prevent damage to downstream property."<ref name="NRCS">[[Technical Release 210-60: Earth Dams and Reservoirs \| TR-210-60 Earth Dams and Reservoirs, NRCS, 2019]]</ref>		“Evaluate the effects of seepage for all dams. The evaluation must address all potential embankment and foundation seepage related failure modes, including the potential for internal erosion, erosive flow along defects, internal [[stability]], and uplift pressures to damage the embankment, its foundation, and appurtenant structures. The evaluation should be commensurate with the complexity, function, and [[Hazard Potential Classification\|hazard potential classification]] of the structure. Seepage control and management must be adequate to accomplish the intended reservoir function, provide a safety operating structure, and prevent damage to downstream property."<ref name="NRCS">[[Technical Release 210-60: Earth Dams and Reservoirs \| TR-210-60 Earth Dams and Reservoirs, NRCS, 2019]]</ref>

	“Seepage analyses should begin with the simplest and most conservative method to analyze the embankment and foundation. Perform progressively more detailed and complex analysis to the extent required, establishing that the design features will safety reduce, intercept, filter, and discharge seepage."<ref name="NRCS"></ref>		“Seepage analyses should begin with the simplest and most conservative method to analyze the embankment and foundation. Perform progressively more detailed and complex analysis to the extent required, establishing that the design features will safety reduce, intercept, filter, and discharge seepage."<ref name="NRCS"></ref>

			==Purposes of Seepage Analysis==
			The purposes of completing a seepage analysis for a dam include:
			*Ensuring that seepage does not exit on the face of the dam. This may indicate a potential for internal erosion from an unfiltered outlet.
			*Estimating the phreatic surface for various loading conditions to support slope stability analysis.
			*Estimating seepage quantity to support drain design.

			==Types of Seepage Analysis==
	“One or more of the following methods of analysis, listed in order of increasing complexity or other industry standard practices may be required to determine if the structure will safely accommodate seepage:		“One or more of the following methods of analysis, listed in order of increasing complexity or other industry standard practices may be required to determine if the structure will safely accommodate seepage:
	*"'''Qualitative Methods''' – For some simple structures with favorable conditions, the seepage performance of the structure can be satisfactorily predicted with limited quantitative analysis. The seepage evaluation for these structures should address the same factors as for more complex analyses. Designers can develop seepage control features for these structures using standard practices based on experience and history of satisfactory performance with similar conditions. The analysis should clearly convey the rational used in the analysis and the justification for the seepage control features incorporated into the design.		*"'''Qualitative Methods''' – For some simple structures with favorable conditions, the seepage performance of the structure can be satisfactorily predicted with limited quantitative analysis. The seepage evaluation for these structures should address the same factors as for more complex analyses. Designers can develop seepage control features for these structures using standard practices based on experience and history of satisfactory performance with similar conditions. The analysis should clearly convey the rational used in the analysis and the justification for the seepage control features incorporated into the design.
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	*"'''Numerical Methods''' – Use computer based numerical methods to analyze seepage in cases where graphical solutions are not practical, there is complex stratigraphy or there is a need to account for saturated and unsaturated or transient flow. Designers can use these methods to estimate seepage quantities and pore water pressures an evaluate the exit gradient for embankments and foundations, as well as uplift pressures acting on appurtenant concrete structures or soil blankets.”<ref name="NRCS"></ref>		*"'''Numerical Methods''' – Use computer based numerical methods to analyze seepage in cases where graphical solutions are not practical, there is complex stratigraphy or there is a need to account for saturated and unsaturated or transient flow. Designers can use these methods to estimate seepage quantities and pore water pressures an evaluate the exit gradient for embankments and foundations, as well as uplift pressures acting on appurtenant concrete structures or soil blankets.”<ref name="NRCS"></ref>

	“Analyze downstream slope [[stability]] of new or previously constructed dams under steady-state seepage conditions. Perform the analysis with the reservoir elevation at the highest normal pool level.”<ref name=~~"NRCS"></ref>~~		==Guidance for Seepage Analysis==

	"Existing embankments may not have achieved steady-state conditions. Thus, use the calculated long-term high-level steady-state seepage condition for both new and existing embankments. For existing embankments, compare the computed phreatic surface with field performance and field measurements, when available, to assure that the computed phreatic surface meets or exceeds that which has occurred over the life of the structure.”<ref name="NRCS"></ref>		"Existing embankments may not have achieved steady-state conditions. Thus, use the calculated long-term high-level steady-state seepage condition for both new and existing embankments. For existing embankments, compare the computed phreatic surface with field performance and field measurements, when available, to assure that the computed phreatic surface meets or exceeds that which has occurred over the life of the structure.”<ref name="NRCS"></ref>

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	“If steady-state seepage stability is highly dependent on the success of internal drainage features to control the phreatic surface, check stability assuming partially functioning or plugged drainage systems.”<ref name="NRCS"></ref>		“If steady-state seepage stability is highly dependent on the success of internal drainage features to control the phreatic surface, check stability assuming partially functioning or plugged drainage systems.”<ref name="NRCS"></ref>

			When possible, monitoring data from [[piezometers]] can be used to calibrate seepage models.

	==Best Practices Resources==		==Best Practices Resources==

Grichards at 20:46, 15 March 2023

2023-03-15T20:46:12Z

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	==Best Practices Resources==		==Best Practices Resources==
	{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]]		{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]]
			{{Document Icon}} [[Seepage Analysis and Control for Dams (EM 1110-2-1901) \| Seepage Analysis and Control for Dams (EM 1110-2-1901), USACE, 1993]]
	{{Document Icon}} [[Design Standards No. 13: Embankment Dams (Ch. 8: Seepage) \| Design Standards No. 13: Embankment Dams (Ch. 8: Seepage), USBR, 2014]]		{{Document Icon}} [[Design Standards No. 13: Embankment Dams (Ch. 8: Seepage) \| Design Standards No. 13: Embankment Dams (Ch. 8: Seepage), USBR, 2014]]

Grichards at 22:30, 21 February 2023

2023-02-21T22:30:51Z

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	{{Video Icon}} [[On-Demand Webinar: 3-D Effects on Estimation of Gradients, Seepage Flows and Evaluation of Internal Erosion Potential Failure Modes]]		{{Video Icon}} [[On-Demand Webinar: 3-D Effects on Estimation of Gradients, Seepage Flows and Evaluation of Internal Erosion Potential Failure Modes]]
	{{Video Icon}} [[On-Demand Webinar: Seepage Rehabilitation for Embankment Dams]]		{{Video Icon}} [[On-Demand Webinar: Seepage Rehabilitation for Embankment Dams]]
			{{Website Icon}} [[Technical Seminar: Seepage Through Earth Dams]]

	</br>		</br>

Rmanwaring at 20:07, 20 December 2022

2022-12-20T20:07:10Z

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	==Best Practices Resources==		==Best Practices Resources==
	{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs\|Technical Release 210-60: Earth Dams and Reservoirs ~~(Natural Resources Conservation Service)~~]]		{{Document Icon}} [[Technical Release 210-60: Earth Dams and Reservoirs \| Technical Release 210-60: Earth Dams and Reservoirs, NRCS, 2019]]
	{{Document Icon}} [[Design Standards No. 13: Embankment Dams (Ch. 8: Seepage)\|Design Standards No. 13: Embankment Dams (Ch. 8: Seepage) ~~(Bureau of Reclamation)~~]]		{{Document Icon}} [[Design Standards No. 13: Embankment Dams (Ch. 8: Seepage) \| Design Standards No. 13: Embankment Dams (Ch. 8: Seepage), USBR, 2014]]

	==Trainings==		==Trainings==

Grichards at 06:10, 14 December 2022

2022-12-14T06:10:48Z

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	</br>		</br>
	Citations:		{{Citations}}
	~~<[[references]] />~~

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