THEORY 2.1 EXPANSIVE SOILS Soils which expand when water is added and which shrink when they dry out are called expansive soils. This continuous change in soil volume causes the structures built on this soil to move unevenly and crack. Expansive soils pose a significant hazard to foundations especially for light buildings. The characteristics of expansive soils are due to the presence of swelling clay minerals. As they get wet, the clay minerals absorb water molecules and expand; conversely, as they dry they shrink, resulting in large voids in the soil. Swelling clays control the behavior of any type of soil if the percentage of clay is more than about 5 percent by weight. Soils with smectite clay minerals, such as montmorillonite, exhibit the most profound swelling properties. Expansive soils can be recognized in the laboratory by their plastic properties. Inorganic clays of high plasticity, generally those with liquid limits exceeding 50 percent and plasticity index over 30, usually have high inherent swelling capacity. Expansion of soils can also be measured in the laboratory directly, by immersing a remolded soil sample and measuring its volume change. In the field, expansive soils can be easily recognized in the dry season by the deep cracks in the ground surface. The zone of seasonal moisture content fluctuation can extend from three to forty feet deep. This creates cyclic shrink/swell behavior in the upper portion of the soil column, and cracks can extend up to much greater depths. Foundation Damage by Expansive Soils: Expansive soils damage foundations by uplift as they swell with increase in moisture content. The swelling soils lift up and crack lightly-loaded, continuous strip footings, and frequently cause distress in... ... middle of paper ... ...lime is spread on the top. The soil and lime are lifted by an elevator to a mixer carried on a travelling platform where water is added and mixing is done. The mixture is then discharged onto the subgrade. It is spread with the help of a grader and compacted. Uniform mixing and accurate control on water added can be ensured in this method. The only disadvantage is that the plant is costly. Stationary Plant method In the stationary plant method, the excavated soil is brought to a stationary mixing plant. At the plant, lime and water are added and mixed with the soil. The mixture is then transported back to the desired location, dumped, spread and compacted. This method affords an accurate proportioning of materials and thorough mixing. The depth of treatment can be easily controlled. The method is slower and may prove expensive due to additional haulage of the soil.
As we have observed throughout the centuries, colonialism has immensely shaped the majority of countries of modern society. In the essay “The Impact of Colonization and Western Assimilation on Health and Wellbeing of Canadian Aboriginal People”, Cathy MacDonald & Audrey Steenbeek developed significant points that reflect as connections to the essay “Virgin Soils Revisited” emphasizing the devastating impact colonialism has had on the wellbeing and health initiatives imposed on the Native Americans and the Aboriginal people of Canada to this day. Both indigenous populations have endured the hardships of poor health, racial issues such as oppression, and cultural assimilations due to the long-lasting effects of colonialism.
As you may or may not know there are many types of farming. For those farming types, there are many tillage methods used. Depending where the farm is located is how the farmer knows what method to use. The methods used are No Till, One pass, Conventional, Conservation, and chisel plow plus. Let’s start out with No Till.
Three substances mainly make fertilisers: nitrogen, phosphorous and potassium. Their percentage in the solution will change the effectiveness on a determinate plant; for example is recommended to use high proportion of nitrogen fertilizers during the spring growth of spurts. The fertilisers can be spitted in two categories: organic that contains a low level of nitrogen, phosphorous and potassium and aren’t toxic to the environment and synthetic that are made by a high concentration of the three substances and can be corrosive to the environment if are overused.
Once you have determined the feel of the soil (plastic, silty, sandy, or smooth) and made a ribbon, compare the length of the ribbon on the soil texture table to find out your soil
Moisture from rain and the elements are retained at the bottom of your home, causing dirt, mulch, and mud to splash on the foundation. Not
Soil liquefaction describes a phenomenon whereby a saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid. The phenomenon is most often observed in saturated, loose (low density), sandy soils. This is because the loose sand has a tendency to compress when a load is applied; dense sands by contrast tend to expand in volume. If the soil is saturated by water, then water fills the gaps between soil grains. In response to the soil compressing, this water increases in pressure and attempts to flow out from the soil to zones of low pressure (usually upward towards the ground surface). However, if the loading is rapidly applied and large enough, or is repeated many times (e.g. earthquake shaking, storm wave loading) such that it does not flow out in time before the next cycle of load is applied, the water pressures may build to an extent where they exceed the contact stresses between the grains of soil that keep them in contact with each other. These contacts between grains are the means by which the weight from buildings and overlying soil layers are transferred from the ground surface to layers of soil or rock at greater depths. This loss of soil structure causes it to lose all of its strength. According to the
In April 2013, a special memorial playground opened in Sea Bright, NJ. The project, The Sandy Ground Project: Where Angels Play, was organized by New Jersey’s Firefighter’s Mutual Benevolent Association. The playground was one of twenty-six playgrounds being installed in New Jersey, New York, and Connecticut towns honoring the children and teachers killed in the massacre at Sandy Hook Elementary School. Each town that received a playground was a town directly impacted by Superstorm Sandy. This particular playground is dedicated to Anne Marie Murphy, a special education teacher, wife, mother, and hero who passed away during the horrific shooting and is located on Sea Bright Beach which was brutally devastated by Superstorm Sandy.
Proctor test is a laboratory method of experimentally determining the optimal moisture content at which a given soil type will become most dense and achieve it’s maximum dry density. The main principle of the test is compaction process by which the bulk density of an aggregate of matter is increased by driving out air. For any soil , for a given amount of compactive effort, the density obtained depends on the moisture content. Standard proctor test properties shown in The test show that moisture content is between 3.9 % and 18.2 %. Standard proctor test properties shown in Figure 13.
soil sample. Figure 4.2 shows the result of liquid limit. Table of Atterberg limit results are shown in Appendix E. The liquid limit shown is 55 %, taken at the 20 mm penetration. The liquid limit of 55 % shows the soil has a high plasticity and demand of water to achieve a liquid state.
Slow Release - This is also a popular option. The granules are just spread out on top of the soil and dissolve over a long period of time. The downside to this method is that you cannot determine when the plants are fed, leading to inconsistencies.
Phytoextraction is the uptake and storage of pollutants in the plants stem or leaves. Some plants, called hyperaccumulators, draw pollutants through the roots. After the pollutants accumulate in the stem and leaves the plants are harvested. Then plants can be either burned or sold. Even if the plants cannot be used, incineration and disposal of the plants is still cheaper than traditional remediation methods. As a comparison, it is estimated a site containing 5000 tons of contaminated soil will produce only 20-30 tons of ash (Black, 1995). This method is particularly useful when remediating metals. Some metals are also being recycled from the ash.
Home gardens offer a wide variety of benefits to the environment and serve a diverse group of people. Home gardening provides a source of fresh produce and free of chemicals, it also gives you complete control over the chemicals and products used during the growing process. A home garden allows you to pick the produce when its ripe, unlike produce at the store is often picked before its fully ripe. The quality and flavor of the freshly picked produce from home is better than the produce that might have unknown chemicals and was likely picked several days or weeks before being sold. The produce retains more nutrients when consumed shortly after being picked, making your home garden vegetables a healthier option. A garden also provides a positive environmental impact. The compost allows you to recycle certain kitchen and yard waste into a nutrient-rich additive for the garden. This provides natural fertilizer for you plants and reduces the wastes you produce. If you choose to avoid or limit chemical use, you reduce pollution from your gardening activities. Besides being good for the environment gardens have environmental gains for us. Gardening help control urban temperatures, If the environmental landscape design is effective it can cool your home in summer and warm it in winter, it can also reduce the energy cost by up to 20%. Gardening, and all the physical activity that goes along with it, leads to a better overall physical health, weight loss, improve you bones, and reduces the risk of having osteoporosis. “In a study of 3,310 older women, researchers from the University of Arkansas found that women involved in yard work and other types of gardening exercises had lower rates of osteoporosis than joggers, swimmers, and women wh...
...ce water can leak onto the aquifer in your underground source of drinking water so you need to check your water. Some warnings signs of a sinkhole can gradual localized ground settlement doors and windows fail to close properly cracks in a foundation a circular pattern of ground cracks the sinking area Vegetation stress due to a lowered water table.