A Review on Effects and Control of Seepage through Earth-fill Dam

Omofunmi, O. E.; Kolo, J. G.; Oladipo, A. S.; Diabana, P. D.; Ojo, A. S.

doi:10.9734/cjast/2017/28538

Cited by 31 publications

(15 citation statements)

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“…It is a large annual regulation reservoir used primarily for flood control, taking into account the comprehensive utilization of irrigation, industrial and urban water. The total reservoir capacity is 922 million m 3 different reservoir water level behaviors are analyzed. It is found that rapid drawdown of the reservoir water level decreases the stability of the upstream slope.…”

Section: Field Measurements Of Dam During Droughtmentioning

confidence: 99%

“…It is a large annual regulation reservoir used primarily for flood control, taking into account the comprehensive utilization of irrigation, industrial and urban water. The total reservoir capacity is 922 million m 3 The dam is a 1545.4 m long earthfill dam ( Figure 2). The crest is 7.0 m wide, at an elevation of 110.40m.…”

Section: Field Measurements Of Dam During Droughtmentioning

confidence: 99%

“…Rapid change from drought to flood brings a sharp rise in reservoir water level. Both such rapid rise of the phreatic line and reverse seepage in the case of sudden drawdown can lead to internal erosion of the dam and instability of the dam slope [3,4]. Research on slope instability due to rapid drawdown is plentiful [3,[5][6][7], but works on unsteady seepage and slope stability during rapid filling, and especially during wet-dry cycles with crack formation, are scarce [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…Under extreme hydrological conditions, soil characteristics and unsteady seepage through dams are complex problems due to the influence of cracks and unsaturation. According to a study of cracks on a dam slope and unsaturated soil characteristics under severe drought conditions, it is found that the key factor that affected the crack width was not soil water content, but water content gradient [3,10]. To study soil characteristics under dry-wet cycles, Zhang [11] combined many experimental data sets to determine how the moisture absorption-desorption curve varies with the number of dry-wet cycles.…”

Section: Introductionmentioning

confidence: 99%

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Unsteady Seepage Behavior of an Earthfill Dam During Drought-Flood Cycles

Marenče

Bricker

2018

Geosciences

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Climate change with extreme hydrological conditions, such as drought and flood, bring new challenges to seepage behavior and the stability of earthfill dams. Taking a drought-stricken earthfill dam of China as an example, the influence of drought-flood cycles on dam seepage behavior is analyzed. This paper includes a clay sample laboratory experiment and an unsteady finite element method seepage simulation of the mentioned dam. Results show that severe drought causes cracks on the surface of the clay soil sample. Long-term drought causes deeper cracks and induces a sharp increase of suction pressure, indicating that the cracks would become channels for rain infiltration into the dam during subsequent rainfall, increasing the potential for internal erosion and decreasing dam stability. Measures to prevent infiltration on the dam slope surface are investigated, for the prevention of deep crack formation during long lasting droughts. Unsteady seepage indicators including instantaneous phreatic lines, equipotential lines and pore pressure gradient in the dam, are calculated and analyzed under two assumed conditions with different reservoir water level fluctuations. Results show that when the water level changes rapidly, the phreatic line is curved and constantly changing. As water level rises, equipotential lines shift upstream, and the pore pressure gradient in the dam’s main body is larger than that of steady seepage. Furthermore, the faster the water level rises, the larger the pore pressure gradient is. This may cause internal erosion. Furthermore, the case of a cracked upstream slope is modelled via an equivalent permeability coefficient, which shows that the pore pressure gradient in the zone beneath the cracks increases by 5.9% at the maximum water level; this could exacerbate internal erosion. In addition, results are in agreement with prior literature that rapid drawdown of the reservoir water level is detrimental to the stability of the upstream slope based on embankment slope stability as calculated by the Simplified Bishop Method. It is concluded that fluctuations of reservoir water level should be strictly controlled during drought-flood cycles; both the drawdown rate and the fill rate must be regulated to avoid the internal erosion of earthfill dams.

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Section: Field Measurements Of Dam During Droughtmentioning

confidence: 99%

“…It is a large annual regulation reservoir used primarily for flood control, taking into account the comprehensive utilization of irrigation, industrial and urban water. The total reservoir capacity is 922 million m 3 The dam is a 1545.4 m long earthfill dam ( Figure 2). The crest is 7.0 m wide, at an elevation of 110.40m.…”

Section: Field Measurements Of Dam During Droughtmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Unsteady Seepage Behavior of an Earthfill Dam During Drought-Flood Cycles

Marenče

Bricker

2018

Geosciences

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“…(Irzooki, 2016) was used SEEP/W code to run on homogenous earth dam models with horizontal toe drain, a new equation was found for computing the quantity of seepage. (Omofunmi et al, 2017) reviewed on effects and control of seepage through earth-fill dams. San Luis dam used to evaluate the unsaturated and transient seepage analysis in which pore-water pressures at failure and progression of the phreatic surface through the fine-grained core for drawdown stability analyses (Stark et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Estimating Seepage Quantity through Homogenous Earth-Fill Dam with Horizontal Drainage Using Different Methods

2020

ZJPAS

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Seepage is the main cause of failure of earthen dams; to prevent this failure, excessive seepage problems should be controlled. In this study, lowest seepage quantity through homogenous earth dam with horizontal filter by different methods was estimated. SEEP/W code in (GeoStudio software 2012) and (Slide software 6.025) was used to investigate 972 models with various upstream and downstream face slopes, horizontal filter lengths, free boards, top widths, dam heights and permeability coefficients. Results showed that, comparing the seepage rates obtained from Slide and GeoStudio softwares has average differences of ratio of seepage discharge to permeability coefficient and filter length (q/kL) was less than 2%. Furthermore, nonlinear empirical equation was developed using (SPSS 22) program. The comparison of seepage quantity measured by SEEP/W and Slide versus its quantity calculated from empirical equations gave a coefficient of determination (R 2 = 0.815, 0.788) respectively. Multilinear perceptron (MLP) was used as suitable type of artificial neural network (ANN) with a base structure (5-4-1) in which 75% of data sets were for training and 17.2% were for testing. The quantity of seepage predicted by ANN compared with obtained seepage rates from SEEP/W and Slide has (R 2 =0.923, 0.942) respectively. Finally, the average percent of errors of empirical equation, Slide Program and ANN was 15.814%, 8.519% and 1.060% respectively. This means that, seepage quantities obtained from ANN was more accurate than other methods may be due to different ways of analysis.

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