Performance Of Embankment Dams Research Articles

A new approach for identification of dispersivity class of soils by combining physical and chemical tests

The safety and performance of embankment dams after impounding water are highly related to the characteristics of the selected dam material. Impermeability is achieved by using clay soils as the core material in embankment dams. It has been observed that there are many collapsed dams, especially when dispersive soils with very low internal erosion resistance are used in the impermeable zone. For this reason, such soils should be determined at the design stage and not used in the construction of embankment dams. The dispersion mechanism is known to be controlled by clay mineralogy and cations in the pore fluid of soil. The physicochemical behaviour of the clay-water system is crucial to clarify the dispersion mechanism. Physical and chemical tests used for determining the dispersibility potential of soils are extensive and time-consuming methods. An alternative method has been proposed within the scope of this study. Three user-friendly and practical models based on Gene Expression Programming (GEP) were produced using chemical and double hydrometer test results to predict dispersion percentage (D%). In addition, a new classification criteria was proposed to identification of dispersivity class based on pinhole test data. If the dispersion percentage is less than 12% is soil is classified as non-dispersive, the dispersion percentage is between 12% and 30% and greater than 30%, it is defined as intermediate and dispersive, respectively. With this proposed criterion, more consistent and successful results were obtained for the dispersivity class.

ICOLD 2023, Gothenburg Sweden: Turkish experience of the February 2023 seismic event

This technical briefing provides a summary of the findings and assessments presented by the DSI (State Hydraulic Works, Türkiye) team during the ICOLD 2023 meeting regarding the performance of embankment dams during the seismic events that occurred in February 2023. Two powerful earthquakes with moment magnitudes (Mw) initially estimated to be between 7.5 and 7.8 struck the eastern Anatolian Fault Line, impacting several embankment dams in the region. The seismic activity resulted in significant lateral displacements, settlements and cracks in the embankment dams structures. For the first earthquake, peak acceleration recorded at the nearest station (TK4614 – Pazarcik) was 2.21g, for the second earthquake, the peak acceleration recorded at the nearest station (TK4612 – Goksun) was 0.59g. The presentation at the conference, as reported here, provided valuable insights into the performance of the embankment dams during and after earthquakes.

Performance-based seismic assessment of vulnerability of dam using time history analysis

The current performance-based seismic assessment procedure can be computationally intensive as it requires many time history analyses (THA) each requiring time intensive post-processing of results. Time history analysis is a part of structural analysis and is the calculation of the response of a structure to any earthquake. It is one of the main processes of structural design in regions where earthquakes are prevalent. The objective of this study is to evaluate the seismic performance of embankment dam located on the Oued RHISS in the Province of AL HOCEIMA using the THA method. To monitor structural behavior, the seismic vulnerability of structure is evaluated under real earthquake records with considering the soil-structure-fluide interaction. In this study, a simple assistant program is developed for implementing earthquake analyses of structure with ANSYS, ground acceleration–time history data are used for seismic analysis and dynamic numerical simulations were conducted to study and identify the total response of the soil-structure system.

Estimation of Earthquake-Induced Crest Settlements of Embankments

Problem statement: Freeboard requirement, a major consideration in the design of embankment dams, is controlled to a great extent by the crest settlements during earthquakes. Approach: The parameters that influence earthquake induced crest settlement had been studied using 152 published case histories on performance of embankment dams during earthquakes. Results: Based on the results a correlation had been proposed for obtaining preliminary estimates of earthquake-induced crest settlements. The correlation used the ratio of the peak horizontal ground acceleration and the yield acceleration as the estimator. Conclusion/Recommendations: The database analysis also indicated that crest settlements are larger where the fundamental periods of the embankment were similar to the predominant periods of the earthquake. Earthquake magnitude and the vertical component of earthquake ground motion, on the other hand, appeared to have a small influence on crest settlement.

Implications of pyritic rockfill on performance of embankment dams

Evidence from the extractive industries shows the impact of the historic use of pyritic materials as rockfill in tailings management and mine waste disposal facilities and demonstrates the often detrimental influence on geotechnical and geochemical performance. The oxidation of pyrite and other sulphide minerals can result in significant changes in the structural zones of embankment dams, and may have serious implications for the construction of both tailings-confining and water-retaining structures. The presentation on this topic at the 2006 BDS conference in Durham revealed a surprising lack of knowledge on the subject among many dam engineers. This paper presents, in summary, the geotechnical and geochemical implications of the untoward inclusion of even small quantities of pyritic rockfill on embankment performance using, in particular, a recent embankment rehabilitation project in Portugal to exemplify the associated problems. The paper concludes with a brief review of the methods available to correct the effects of oxidation within an embankment and to improve stability and environmental performance.