Visual Classification and Microscopic Analysis

For the visual classification portion of the lab several tests were performed to determine the type of soil being tested using the naked eye. The soil seemed to have a rounded (smoothly curves sides and no edges) shape, a slight organic odor, a light grey/brown color consistency, and depending on the area of the container a dry or moist condition. A stoppered tube test was preformed to gage the range of the particle sizes. It was noted that the soil was mostly sand because the particles immediately settled out during the test. Some fines were noticed during the testing and very few particles of organic matter were floating on the top of the water. The soil had a high dispersibility because it settled in under 4 seconds and was roughly 97% sand, 2.5% fines and .5% organic. Further testing also revealed that the hardness of the soil in question was low because it took little effort to break. Overall the soil was believed to be quarts due to the characteristics tested above.The soil being tested also had no dry strength, specimen crumbled when handled. From a toughness perspective the soil had none and a 3mm thick thread could not be rolled from the soil, making the soil nonplastic in nature.

During the microscopic analysis portion of this lab a microscope with magnification levels of 10X, 60X, and 200X were used to inspect the soil sample.At 10X (Figure 1M) magnification the soil appears to be a light brown in nature having a rounded particle shape, with particle sizes all relatively the same size. As the magnification was increased to 60X (Figure 2M) the color of the particles began to look more transparent, the edges of the particles became more angular, and the fines particles became visible. At this level of magnification organic particles could be seen and particles of various colors were observed. Finally at the 200X (Figure 3M) level the soil clearly had a distinct angular edge, the individual particles looked almost clear and the fines particles could clearly be seen between the sand particles.

The USCS classification of this soil would be a uniformly graded sand, this is made apparent in the lab due to the uniform size of the particles and the low content of fines and gravels. When comparing the USCS classification to the visual classification the soil being tested falls into the sand category based on the grain size distribution.

Figure 1M: 10X Magnification

Figure 2M: 60X Magnification

Figure 3M: 200X Magnification