DESCRIPTION

Technical Description

A descriptive method in the study of seepage and groundwater flow is the visualisation of the streamlines and their graphical representation as a flow net. The flow net provides information about the seepage of water in dams and sheet piles.

HM 169 can be used to visualise streamlines in seepage and groundwater flow on different models using a contrast medium. Furthermore, the effects of water pressure on different structures are displayed as pressure curves.

The trainer consists of a transparent tank with a sand filling. Various models can be placed in the sand bed to demonstrate typical structures. The experimental section is separated from the feed and discharge chambers by fine mesh screens. A valve is used to adjust the water supply. Using a contrast medium it is possible to make streamlines visible, as they occur in seepage and groundwater flow. A tempered glass viewing window allows for optimal observation of the experiments.

Various models allow an extensive range of experiments, such as pressure distribution on retaining walls or seepage and groundwater flow under sheet piles. The "foundation" and "retaining wall" models are equipped with tubes to show the pressures on the models.

In the experimental section there are measuring connections to detect groundwater levels. Groundwater levels are displayed on 14 tube manometers.

HM 169 contains a closed water circuit with storage tank and pump.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments

- determining flow nets in permeable media graphically
  * streamlines under a sheet pile
  * streamlines through an earth dam
  * drainage at an open ditch
- determining the pressure curve at a foundation
- determining the pressure curve at a retaining wall
- groundwater levels over time in various models