Influence of Geological Structure on Dam Behavior and Case Studies

Abstract

Complex engineering projects including large dams require extensive reconnaissance. The study of geological relationships is therefore of major importance, with emphasis on the characteristics of the geological structures. Accordingly, geologic structure affects dam site and reservoir behavior in three ways: (1) its impact on the geomechanical properties of rocks; (2) the importance of geologic structures in the identification and assessment of karst hydrogeology; and (3) its role in seismotectonic and seismic risk analysis of dam projects. Site geology and availability of various geologic data obtained from site investigation are key points in dam construction. Geological structure plays an important role in dam site geology and imposes major limitations on dam behavior during and after construction stages. This role has its own effect on major subjects such as: morphotectonics of rivers; geotechnical properties and engineering geology of dam sites; and hydrogeology of dam abutments and reservoir. The variability and complexity of geological structures regarding their tectonic situation result in different scenarios regarding dam's behavior. This chapter examines the link between geological structure and dam behavior during and after construction period by describing four dam case examples: two earth (Marun and Gotvand) and two concrete (Karun-1 and -3) dams in Iran.

Study of Geometric Elements for the Proposed Protecting Dam Reservoir in Al-Fat'ha Area, Iraq

“…Relationships between the geometric elements and water level, and between each, are essential in geometric studies. It is possible by these relationships to predict the changes that may occur on the ground surface after the beginning of the storage [17]. In addition, to determine the exposures of geological formations that may be submerged when the water level is raised in the reservoir.…”

“…The member is not exposed to any part of the proposed reservoir. In general, the thickness of these rocks ranges from (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) m, except for limestone, its thickness reached 6 m [2]. The upper member, which exposed in the western and southwestern sides of the studied reservoir, consists of sequences of limestone, claystone, siltstone, and thin layers of gypsum [2] that are less dangerous on the foundations of dam and the reservoir, Figure 2.…”

Upstream and Downstream Changes in the Channel Width and Sinuosity Due to Dam Construction in Tropical Rivers: The Case of Colombia

“…Although geology is considered essential in influencing river morphology, a few studies have considered the riverbank's composition in the study of the morphological effects of dams. It is more common to use the geological information to define the right place to build a dam, analyzing, for instance, the rock type and geological structure [86]. Studies dealing with the morphological effects of dams use geologic information to obtain a context of the area of interest with lithological descriptions at a regional scale, but this information is not included in the morphodynamic analysis.…”