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Quicksand Lab Report

Decent Essays

Quicksand is a condition forms when saturated loose sand is suddenly agitated (loss its stress force). Thus, lose it strength as it cannot support its own weight. In the laboratory, the sand was compressed when a load is applied on it and later the water fill in the gaps between the sand grains and as a result, the sand becomes saturated and called “semiliquid state”. Furthermore, effective stress is calculated by total stress and pore water pressure.

where, effective stress; = total stress; and = pore water pressure.
The pore water pressure keeps increasing until the effective stress of soil equals to zero, hence, the strength of the soil equals to zero as well. There is no more intergranular connection between the soil particles and the soil started to behave like a liquid.

In the experiment, water is flowing through the soil from left side entering right side of the tank by upwards motion (see Figure 5). This is happen as critical gradient is exceeded, the soil moves upward, and the water boiling and piping occurs and push up the water. The water is flowing through the way like a pipe inside the soil, the soil being pushed up and boils. This when the quicksand condition occurs. As soil loses its strength, the foundation sinks because it does not have any more strength (no more intergranular connection between particles) and cannot support the weight anymore. However, later when the water flow stops, soil regains its strength. Moreover, the set up of the sand tank create water to gradually increase the water level head difference between the two sides until a quicksand condition and piping is observed.

Figure 5: Picture of The Tank after Quicksand and Piping Occurred

Note: The blue linein figure 5 is represent flow of water inside the tank in the experiment after the set-up tank been removed.

Part 3: Engineering Design Applications

Explain why and how quicksand conditions and piping have to be considered in the design of embankment dam. In addition, provide an example of a dam failure where quicksand conditions and piping caused the failure. You can include one figure to illustrate your answer.
Dam is a barrier constructed that hold water to form a reservoir generate as a water supply. It is

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