Drawing flow net for seepage under the sheet piles Abaqus

Project Overview

In this tutorial, the seepage of water through soil beneath a concrete dam is simulated using Abaqus. The main objective is to obtain the flow lines and equipotential lines from the numerical analysis and use them to construct the flow net.

This example is based on Example 9.10 from the Sam Helwany book. The numerical model represents seepage through the soil beneath a concrete dam containing a row of sheet piles.

Model Description

The concrete dam has a 60-m-wide base and is underlain by a 90-m-thick soil layer. The permeability coefficient of the soil is k = 0.03 cm/s, and the soil is assumed to be isotropic.

A row of sheet piles is included beneath the concrete dam. The sheet piles have an embedded length of 15 m and are located at the heel of the dam.

Sheet Pile Modeling

In the numerical model, the sheet pile is represented by a narrow V-shaped gap. The sheet piles are positioned at the heel of the dam to increase the seepage path beneath the structure.

Water Reservoir

The water level in the reservoir is set to a height of 12 m. This water head provides the hydraulic driving force for the seepage through the soil beneath the dam.

Boundary Conditions

Appropriate hydraulic boundary conditions are applied to simulate the seepage problem. The bottom surface of the concrete dam is defined as an impermeable boundary.

These boundary conditions control the movement of water through the soil and allow the seepage path around the sheet piles to be reproduced in the Abaqus model.

Element Type

The soil is modeled using a plane-strain coupled pore fluid element. This type of element allows the coupled behavior of the soil skeleton and pore fluid to be considered in the seepage analysis.

Equipotential Lines

The equipotential lines are obtained from the hydraulic results of the Abaqus analysis. Each equipotential line represents points having the same hydraulic head.

Flow Lines

The flow lines represent the paths followed by water as it flows through the soil beneath the dam and around the sheet piles.

Flow Net

The flow lines and equipotential lines are superimposed to form the flow net. The resulting flow net provides a graphical representation of the seepage pattern beneath the concrete dam and around the sheet piles.

Results

The Abaqus results are used to visualize the seepage behavior beneath the concrete dam. The flow lines and equipotential lines are extracted from the numerical results and superimposed to obtain the final flow net.

This example demonstrates how Abaqus can be used to simulate seepage beneath hydraulic structures and to visualize the effect of sheet piles on the seepage path.

What You Will Learn

• How to model seepage through soil beneath a concrete dam.
• How to model sheet piles in a seepage problem.
• How to define an isotropic soil permeability.
• How to define hydraulic boundary conditions.
• How to use plane-strain coupled pore fluid elements.
• How to obtain equipotential lines from Abaqus results.
• How to obtain flow lines from Abaqus results.
• How to construct a flow net using Abaqus results.
• How to visualize seepage around sheet piles.

Key Features

• Seepage analysis beneath a concrete dam.
• Example 9.10 from the Sam Helwany book.
• 60-m-wide dam base.
• 90-m-thick soil layer.
• Isotropic soil.
• Permeability coefficient of 0.03 cm/s.
• 15-m embedded sheet piles.
• Sheet piles modeled as a narrow V-shaped gap.
• 12-m-high water reservoir.
• Impermeable bottom surface of the concrete dam.
• Plane-strain coupled pore fluid elements.
• Flow lines and equipotential lines.
• Final flow-net construction.
• Free Abaqus tutorial.