Week 9 Lab Goals

The goals for the lab today is test using the water and the grid, and to start making the presentation for next week and have that finished by the end of the week due to majority of the group heading home for the weekend.

Intrasoil Grid Phase 2

As the initial design for the grid was being created, the leftover material proved useful for a second kind of grid. This grid is disconnected and instead of supplying an outline of a structure, the pieces enclose the soil. A picture can be seen below:

The same measurements were taken as in phase 1. The angle decreased only by .8% upon applying immediate pressure. After 30 minutes, the angle decreased by another 18%. So far, the grid structures may actually be weakening the slope instead of helping. There are a few more that need to be tested. Grid structures 1 & 2 also need to be tested under rain simulation.

Intrasoil Grid Phase 1

This weekend, a few of the grid designs were tested under applied pressure. The first tested was our very initial design, simply structural squares. A photo can be seen below:

The first test resulted in failure after less than a minute due to the container being bumped. The next test was successful and ran for 30 minutes with the bricks used as applied pressure. Measurements were taken before applying pressure, immediately after, and after the 30 minute time interval. The angle from the first stage to second had a 6.22% increase. This may be due to the compression of the soil as the bricks were laid or from sliding of the soil. The change between immediately after and after 30 minutes was a 6.27% decrease. 

A decrease shows that the soil eroded. This may have to take into the account the change in slope as a result of putting the grid in place. Testing on these changes have been done and will be added to the blog in coming posts. This angle decrease is a larger percent from that of the toe wall. Multiple structures of the grid will be tested in the coming week.