Planet X Module 4
Use this activity as a demonstration of the effects of shaking on different types of foundation soils.
1. Shake Table
2. Quikrete Play Sand or similar fine-grained sand.
3. Clear plastic cup or glass beaker.
4. Velcro for top of shake table and bottom of all materials.
5. Small wooden blocks with small hole drilled into center (size 40 drill bit), wooden skewers and corks for building facsimiles.
Diagram of building facsimile using a wooden block base with a cork mass
attached with a wooden skewer.
Figure 1 Diagram of building facsimile using a wooden block base with a cork mass attached with a wooden skewer.
6. Large, flat rock and piece of soft foam cut to same height.
7. Measuring cup and spoons.
8. Small funnel and plastic medicine dropper with bulb syringe removed or a plastic straw.
1. Construct Shake Table. The following sites have examples and directions for building three different types ranging from simple to motorized. http://lahr.org/john-jan/psn/psn.html http://mceer.buffalo.edu/education/exercises/shtable.asp
2. Gently fill plastic cup with sand almost to the top. Mark level of sand. Attach to shake table with Velcro and shake – sand level should drop due to settlement.
3. Gently refill cup to same level with new sand and attach to shake table with Velcro. Push medicine dropper tube into sand and fill with water using funnel. Final water level should be below the sand level so that the top layer of sand is dry (Approximately 90 mls of water per one cup of sand, water level can also be distinguished on a clear plastic cup). Gently remove funnel and shake – water should rise to top wetting top sand layer.
Diagram of plastic cup of sand filled to just below top using a funnel and
medicine dropper tube.
Figure 2 Diagram of plastic cup of sand filled to just below top using a funnel and medicine dropper tube.
4. Attach building facsimiles to foam and rock using Velcro. (Adhesive may be needed to attach the Velcro to the rock.) Attach both to shake table with Velcro and shake. After shaking ends the building on the foam should continue to vibrate longer.
Figure 3 Photo of shake table with a design similar to John Lahrs (see site link above) constrained to move in one dimension and powered by a variable speed drill. The black stripes on the platform are Velcro. Velcro was attached to the rock using a spray adhesive.