Background Information
Nong Bon Retention Pond was built in 1999, with total area of 644 rai (Thai unit for area) , with the purpose to solve the severe flooding issues of Bangkok. It consists of 3 ponds, one beside each other, each 10 meters deep, with the capacity of 5,090,700 cubic meters of water storage. During drought seasons, the water level of Nong Bon Retention Pond will be controlled at a bit lesser water level than the kongs. By doing this, the water will be forced to flow into the pond and pump out of the pond, this water process is a natural method of water treatment. During raining seasons, the water level in the pond will be reduce by 2 -5 meters, in order to allow the rain to flow into the pond, able to store up to 4 million cubic meters.
The Specific gravity of soil refers to the specific gravity of the solid matter of the soil, which is expressed as Gs. The specific gravity of a solid is the ratio of the weight of a given volume of material to the weight of an equal volume of water at 293 kelvin, or 20 celsius (Pike). This reveals how much lighter or heavier the material is than water. Specific gravity is a dimensionless quantity, meaning it is not expressed in units. Soil’s specific gravity depends on the density of the minerals making the individual soil particles (Pike). The values of the specific gravity of each type of soil are the following: |
The different specific gravities of soil allows civil engineers to determine the soil type as well as whether or not this soil type is suitable for construction. Selecting a building site while maintaining careful consideration of the soil type will ensure stability in the foundation of the house (Berry). The texture of the subsoil indicates the building site potential. If the subsoil is coarse, the soil type would either be sand or silty sand, causing water to drain through it rapidly (Anderson). Coarse textured soil are easily excavated and are very stable during both wet and dry conditions. The soil type of fine textured soil is inorganic clay, which have the tendency to expand as the amount of moisture increases and contract as it decreases (Anderson). Lack of stability in this soil would be able to crack the foundation of the house. Organic soil is not very suitable for construction as the soil would be very compact, however is an adequate garden site (Anderson). |
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Hypothesis
From our observation during our collection of samples at the Nong Bon conservation center, we noticed that the soil nearer to the shoreline at 5.3 m had more clay-like characteristics than the soil further from the shoreline at 26.5 m. Clay, like soil, has the tendency to expand as the amount of moisture increases and will contract when the moisture decreases. If the building site could easily become altered by the moisture, there will be lack of stability in the soil, which will crack the foundation of the house. According to this fact, the soil at 26.5 m from the shoreline is more likely to have the specific gravity near 2.65 since there is more sand characteristic, and the soil at 5.3 m from the shoreline will have the specific gravity near 2.00 or even less than since it have more clay characteristic. Therefore, soil that is further from the shoreline would be more suitable for a building site (for construction) that the one that is nearer to the shoreline.
Variables
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Independent Variable: Distance of soil from the shore (m)
Dependent Variable: Specific gravity of soil Controlled Variables: Mass of soil in the flask during the vacuum pump and tumbling process (g), dryness of the soil after drying in the oven, and volume of the flask (mL), volume of water during the vacuum pump and tumbling process mL |
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Materials Required
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