Drainage network for water conservancy projects

Short Description:

Product Detail

The drainage network in water conservancy projects is a system used to drain water bodies in water conservancy facilities such as dams, reservoirs, and levees. Its main function is to effectively drain seepage water inside the dam body and levees, lower the groundwater level, and reduce pore water pressure, thus ensuring the stability and safety of water conservancy project structures. For example, in a dam project, if the seepage water inside the dam body cannot be drained in a timely manner, the dam body will be in a saturated state, resulting in a decrease in the shear strength of the dam material and increasing potential safety hazards such as dam landslides.

Drainage Principle
- The drainage network in water conservancy projects mainly utilizes the principle of gravity drainage. Inside the dam body or levee, due to the existence of a water level difference, water will flow from a high place (such as the seepage area inside the dam body) to a low place (such as drainage holes, drainage galleries) under the action of gravity. When water enters the drainage holes or drainage galleries, it is then drained to a safe area outside the dam body, such as the downstream river channel of the reservoir or a special drainage pond, through a pipeline system or channel. At the same time, the existence of the filter layer enables the soil structure to remain stable during the drainage process, avoiding the loss of soil inside the dam body or levee due to drainage.

Applications in Different Water Conservancy Projects
- Dam Projects:
  - In a concrete dam, in addition to setting up drainage holes and drainage galleries, drainage facilities will also be set up at the contact area between the dam body and the foundation to reduce the uplift pressure on the dam foundation. Uplift pressure is an upward water pressure at the bottom of the dam. If not controlled, it will reduce the effective compressive stress at the bottom of the dam and affect the stability of the dam. By draining the seepage water from the dam foundation through the drainage network, the uplift pressure can be effectively reduced. In an earth-rock dam project, the layout of the drainage network is more complex and needs to consider factors such as the permeability of the dam body material and the slope of the dam body. Usually, vertical drainage bodies and horizontal drainage bodies will be set up inside the dam body, such as drainage sand columns wrapped in geotextiles.
- Levee Projects:
  - Levees are mainly used for flood control, and the focus of their drainage networks is to drain seepage water from the levee body and foundation. Drainage pipes will be set up inside the levee body, and cut-off walls and drainage relief wells will be set up in the foundation part. The cut-off wall can prevent external water bodies such as river water from permeating into the foundation, and the drainage relief wells can drain the seepage water inside the foundation, lower the groundwater level of the foundation, and prevent potential disasters such of piping in the foundation.
- Reservation Projects:
  - The drainage network of a reservoir not only needs to consider the drainage of the dam but also the drainage of the surrounding mountains. Intercepting ditches will be set up on the slopes surrounding the reservoir to intercept surface runoff such as rainwater and direct it to drainage channels outside the reservoir, avoiding rainwater from washing the slopes and permeating into the reservoir dam foundation. At the same time, the drainage facilities of the reservoir dam itself must ensure that the seepage water from the dam body can be drained in a timely manner to ensure the safety of the dam.

Parameter Items	Unit	Example Values	Description
Diameter of Drainage Holes	mm (millimeter)	50, 75, 100, etc.	The inner diameter size of the drainage holes, which affects the drainage flow and the filtration of particles with different sizes.
Spacing of Drainage Holes	m (meter)	2, 3, 5, etc.	The horizontal or vertical distance between adjacent drainage holes, which is set according to the engineering structure and drainage requirements.
Width of Drainage Galleries	m (meter)	1.5, 2, 3, etc.	The width dimension of the cross-section of the drainage gallery, which should meet the requirements of personnel access, equipment installation and smooth drainage.
Height of Drainage Galleries	m (meter)	2, 2.5, 3, etc.	The height dimension of the cross-section of the drainage gallery. Together with the width, it determines its water flow capacity and other characteristics.
Particle Size of Filter Layers	mm (millimeter)	Fine sand: 0.1 - 0.25 Medium sand: 0.25 - 0.5 Gravel: 5 - 10, etc. (examples for different layers)	The particle size range of the materials in each layer of the filter layer, ensuring that it can drain water while preventing the loss of soil particles.
Material of Drainage Pipes	-	PVC, Steel Pipe, Cast Iron Pipe, etc.	The materials used for drainage pipes. Different materials have differences in strength, corrosion resistance, cost, etc.
Drainage Flow Rate	m³/h (cubic meters per hour)	10, 20, 50, etc.	The amount of water discharged through the drainage network per unit time, reflecting the drainage capacity.
Maximum Drainage Pressure	kPa (kilopascal)	100, 200, 500, etc.	The maximum pressure that the drainage network can withstand, ensuring its stable operation under normal and extreme working conditions.
Drainage Slope	% (percentage) or Degree	1%, 2% or 1°, 2°, etc.	The inclination degree of drainage pipes, galleries, etc., using gravity to ensure the smooth drainage of water.