1-¿Cómo se construye una PRESA?/ ¿Cuántos tipos de presas hay/ En RD cuáles de TIERRA y de CONCRETO?

Introduction to Dams and Their Importance

Overview of Dams

• José Espinoza introduces the topic of dams, emphasizing their significance for human life.

• Engineer Raúl Brito, a specialist in dam construction and hydraulic engineering, joins the discussion to share insights on dam technology.

Historical Context

• The first significant dam in the Dominican Republic was the Tavera Dam, completed in 1972. This marked the beginning of important infrastructure projects in the country.

• Other notable dams include Sabana Yegua and several concrete dams like Firmware and La Fecha.

Construction Technologies for Dams

Site Selection Process

• The selection of a site for dam construction involves various factors, including geological studies using modern techniques such as aerial photography.

• Engineers assess foundation conditions to determine rock quality at potential sites; good quality rocks favor earth dam constructions.

Foundation Considerations

• If foundation quality is poor, engineers may opt for earth dams that require less stringent technical specifications.

• Sites with unsuitable foundations can be improved by creating initial barriers or curtains to support construction.

Excavation and Core Construction

Initial Steps in Dam Building

• After site selection and geological assessments, excavation begins. For earth dams, stability is provided by embankments constructed above and below a core made from clay.

Core Stability Techniques

• The core's stability relies on granular materials or compacted clay. A trench is excavated beneath it to locate competent rock layers essential for structural integrity.

Foundation Treatment Methods

Ensuring Structural Integrity

• The foundation's competence is evaluated through standard penetration tests (SPT), which are crucial for determining suitability for high structures (20 to 40 meters).

Treatment Procedures

• Once excavation reaches suitable depths, an initial curtain is created through perforations that facilitate further treatment of the foundation area.

• The method known as "Jean" involves injecting grout into these perforations to enhance foundation strength before proceeding with construction.

Construction Process of Earth Dams

Foundation Preparation and Injection Process

• The foundation is designed to be placed under pressure that does not damage it, ensuring no cracks occur. This involves a series of layers being applied once the initial direction is completed.

• Secondary drilling occurs between primary holes, followed by two injections in specific conditions to ensure proper filling and stability. The trenches are left perfectly sealed after injection completion.

Clay Core Placement

• A clay core is installed, which can vary in difficulty based on infiltration levels; minimal infiltration allows for easier placement in 25 cm thick layers for optimal compaction. Each layer aims for a high density percentage during installation.

• In cases where complications arise, adjustments are made above the core level to maintain structural integrity during construction processes like those seen at the "shock train" site related to the company "La Piña de la Salud."

Drainage and Instrumentation Setup

• Vertical pipes connected to a larger perforated tube facilitate water injection into the trench, which has a depth of 50 to 70 cm with PVC tubes sloped towards designated points at the foundation's ends. Permanent pumping stations are required for continuous water management during core construction.

• Before clay placement begins, instrumentation such as piezometers and inclinometers must be installed to monitor water levels and pressures within the dam structure effectively. These instruments help assess potential risks associated with water pressure fluctuations.

Filtration Systems

• A vertical sand filter is placed at the base of the dam structure, extending from its bottom up through its column, complemented by horizontal filters at contact zones with downstream materials to manage seepage effectively. This dual filtration system enhances overall stability against water flow issues within the dam body.

• The design includes both vertical and horizontal filters that work together to mitigate any leakage or seepage problems that may arise from reservoir operations or rainfall impacts on structural integrity. Filters consist of multiple layers including gravel and sand for effective drainage management.

Construction Steps Overview

• Initial steps involve clearing all vegetation and debris from areas designated for construction while removing low-quality materials from both valley sections and dam abutments before excavation begins down to foundational depths (11–45 meters below spillway levels). Proper site preparation is crucial for successful dam construction outcomes.

• Following site clearance, fill material is placed systematically as part of constructing earth dams, ensuring each layer meets engineering standards necessary for long-term durability and performance under operational conditions once completed.

Overview of Hydraulic Structures

Key Components of the Structure

• The discussion begins with the explanation of filter clay and both vertical and horizontal filters, which are essential for managing water flow in hydraulic structures.

• It is noted that alongside these components, a spillway is constructed to handle overflow from the reservoir when it reaches maximum capacity.

• The elevation at which the spillway operates is crucial; it starts draining excess water entering from the reservoir once filled to its designated level.

• A detailed description of a dam structure reveals it stands 90 meters high, primarily built from clay and other materials, emphasizing its engineering significance.

Structural Layout and Functionality

• The layout includes a service road above the dam for maintenance access, indicating practical considerations in design for operational efficiency.

• The core structure of the dam is highlighted as being critical to its integrity, showcasing how various materials contribute to overall stability and functionality.