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
The article “Down go the dams” by Jane C.Marks aim to provide an informative view on the current pending issue on Dams. The article starts out my mentioning the important nature of dams in our society. For example, Jane C.Marks states that today about 800,000 dams operate worldwide as well as the fact that most were built in the past century, primarily after World War II. Furthermore, the author lays down informative facts about dams such as the fact that dams control flooding and their reservoirs provide a reliable supply of water for irrigation, drinking and recreation which are all very important to society. In an economic standpoint, although it is very high maintenance dams provide jobs for people. The
At Nudgee Beach, erosion was found to have occurred on the edges of the mangrove forest and along the mudflat shorelines. Erosion is typically influenced by natural factors and occurs when pieces of weathered rock or soil are moved – typically by wind and water – from one place to another. Shorelines with lots of sediment and sand are more inclined to be effected by erosional progression. Erosion may also be provoked and accelerated by human interference. For example, if the decision to clear trees and plants from an area is made, erosion is likely to occur as the root systems of plants work to hold the soil in place. If these root systems are removed and erosion does occur, environmental conditions – such as; landslides and flooding – are more likely to take place. Erosion may also cause other plants to tip over, have their underground roots exposed and damaged and contribute to the pollution of local waters; as a result of mud and soil runoff [26]. Erosion at Nudgee Beach was likely to have been influenced by natural factors; however, the development and extension of the Kedron Brook golfing course may contribute to the acceleration of erosional processes and further damage the mangrove
The vials were placed in the water and the oxygen levels were read every 5 minutes until 30 minutes was reached. As the oxygen levels were collected they were put into a table that had all three tubes labeled at each 5-minute increment. After 30 minutes the experiment was completed and the clean up process could begin.
The real question here however is why these dams were installed. Well you see, it all goes back to the Gold Rush. Most accounts of the environmental damage caused by the Gold Rush focus on the direct effects of mining. During the gold rush, many farmers saw the open opportunity to take advantage of miners that had traveled from across the world. They increased the value of their food to outrageous prices.
The thirst for water has lead individuals and organizations to build dams across rivers at an alarming rate. During the early 1900s dams were being built so fast it was no longer big news when a dam was completed. These structures provided controlled irrigation water and hydroelectric power to the communities not only close to the reservoirs and dams, but also provided irrigation water and hydroelectric power to communities many miles away from the river. Negatively blocking the flow of the river has impacted fish ecosystems, increased evaporation of water, and flooded intricately important landscapes. These negative impacts, it can be argued, affect the humans living downstream or within the flood plain of the dam site. Dams
In 1992, The Elwha River Ecosystem and Fisheries Restoration Act of 1992 authorized the US Federal Government to acquire the hydroelectric power projects of Elwha Dam and Glines Canyon Dam, where are located on the Washington State for demolition for habitat restoration and decommissioning. The dam removals began in 2011 and finished in 2014. I wondering that why government decided to remove the dam and what happens in Elwha River after dam removal. In this paper, I write about the following topics: main purpose of the Elwha and Gliens Canyon dam, effects to the Elwha River as well as ecosystem after constructing dam, reasons of the dam removal, process of the dam removal, and effects after dam removal.
The soil has a thick litter layer, but thin humus layers due to fast decomposition. There is also a rapid leaking, which is the downward movement of the nutrients in solution in the soil. Soil is determined by the climate, vegetation, topographic position and soil age.
When deciding whether of not to support the construction of a new dam, we have to use the process of cooperating, communicating, and thinking to come to a logical conclusion that is best for this world. Cooperating is important because it allows people to work together to come to a final decision by using everyones knowledge. Communication is also needed to tell others your opinion and to share the pros and cons of creating a dam. Lastly, thinking like a scientist is greatly needed. When making a decision like this, bias must be out of the opinions given and facts are needed because creating a dam can greatly affect the
1. Maintain a constant water level (head) difference between the two sides of the tank as shown in the diagram by allowing water to overflow through the overflow and outflow tubes. Measure the water level (head) difference.
1. Why was the building of the dam first proposed in 1919 and by whom?
Inflow from the tank was calculated using the known internal dimensions of the tank, the % full reading, and the time step which the data was collected.
The stresses set up in the soil cause deformation of the soil, which occur in three ways:
The Three Gorges Dam is an unfinished project which will be the largest dam ever constructed on the planet Earth. It is situated in China on the third largest river in the world – the Yangtze. The dam has been debated over since the 1919 and is still a hot topic of debate because of its many pros and cons. In 1994 construction began on the dam, and it is expected to be finished by the year 2009. The massive dimensions of the dam are mind boggling and its functions – if the dam actually works – are truly remarkable; however, with such a large structure also comes difficulties, sacrifices, and cynics. The goal of this essay is to lend an understanding of the dam itself, the prospective benefits of
INTRODUCTION: Water assets building is growing massively today. Dams have the most vital part in using water assets. They were developed taxing year before increasing present data about hydrology and hydro mechanics. All through the historical backdrop of the world, dams have been utilized effectively as a part of gathering, putting away and overseeing water expected to manage human advancement. Dams have a lot of positive and negative impacts on the earth. Their advantages like controlling stream administration, subsequently forestalling surges, getting local and water system water from put away water and creating vitality from hydro control. While dam give noteworthy advantage to our general public, their effect on the encompassing incorporates resettlement and migration, financial effect, natural concerns, sedimentation issue, security angles and so on. Notwithstanding their vital social and natural advantages, it is vital to minimize the negative impacts of the hoover dam on the earth with respect to feasible advancement.
The voids are spaces between grains of sand, or cracks in dense rock. All water beneath the land surface occurs within such void space sand is referred to as underground or subsurface water. Subsurface water occurs in two different zones. One zone, located immediately beneath the land surface in most areas, contains both water and air in the voids. This zone is referred to as the unsaturated zone. Other names for the unsaturated zone are zone of aeration and vadose zone. The unsaturated zone is almost always underlain by a second zone in which all voids are full of water. This zone is defined as the saturated zone. Water in the saturated zone is referred to as ground water and is the only subsurface water available to supply wells and springs. Water table is often misused as a synonym for ground water. However, the water table is actually the boundary between the unsaturated and saturated zones. It represents the upper surface of the ground water. Technically speaking, it is the level at which the hydraulic pressure is equal to atmospheric pressure. The water level found in unused wells is often the same level as the water table. AQUIFERS An aquifer is a saturated geologic formation that will yield a usable quantity of water to a well or spring. Ground water occurs in aquifers under two conditions: confined and unconfined. A confined aquifer is overlain by a confining bed, such as an impermeable layer of clay