Soil and rock are the main composition of the planet’s crust. Rock is often considered a consolidated material but soil is described as an unconsolidated remains and deposits of solid particle that have been formed by the breakdown of rocks. Soils can be grouped into two categories depending on the method of deposition. Residual soils have formed from the weathering of rocks and remain at the location of their origin. Residual soils can include particles having a wide range of sizes, shapes and compositions depending on amount and type of weathering and the minerals of parent rock. Transported soils are soils that have been relocated from their original place. Transportation may have resulted from the outcome of gravity, wind, water glaciers or human activities. Transported soil particles are often segregated according to size during the transportation process. The method of transportation and deposition has significant effect on the …show more content…
• Water content: the smaller the moisture in the soil, the greater the soil suction will be, soil suction will hold its maximum value when the soil is free of any moisture (dry). • Plasticity index of soil: soil suction will be greater in a soil which has greater plasticity index than in the one which has lower plasticity index. • History of drying and wetting: soil suction is less during wetting time than it is during drying time. • Soil structure: the size of interstices in a soil depends upon the structure of the soil, change in the formation would lead to change in the size of interstices and thus change the soil suction. • Temperature: temperature changes can change the soil suction, temperature increase would decrease soil tension and result in decrease in suction, and alike, fall in temperature would cause an increase of
How does the bare soil surface type affect the amount of runoff? Speculate why this happens.
The SHANSEP method was first established by Ladd and Froott in 1974 at Massachusetts Institute of Technology (MIT). SHANSEP gives design procedure for clay showing normalized behaviour. It gives a way of taking into account the previous stress history of the soil, particularly overconsolidation. In this method, the sample is consolidated under several times greater stresses than its yield consolidation stress (normally, 1.5 to 4 times) and is then swell back to its field effective stress to minimize the adverse effect of soil disturbance.
Dense to very dense natural and compacted foundation soils had settled a maximum of 4inches or four-tenths of a percent of the wall height. By the comparison of the
Soil erodibility is an estimate of the ability of the soil to resist erosion based on the physical characteristics. Generally, soils with faster infiltration rates, high levels of organic matter and improved structure have a greater resistance to erosion. Sand, sandy loam, and loam textured soils tend to be less erodible to than silt, very fine sand, and clay textured soils. Sediments with high sand or silt contents and areas with steep slopes erode more easily. Similarly, this also applies to highly fractured or weathered rocks (Frankl, Deckers, Moulaert,Van Damme, Haile, Poesen, & Nyssen, 2014). Below is a law on soil erosion.
What is soil? “Soil is a complex mixture of eroded rock, mineral nutrients, decaying organic matter, water, air, and billions of living organisms, most of them microscopic decomposers.” (Miller and Spoolman, 211). As stated, soil is made when a mixture of items such as eroded rock and mineral nutrients come together. Soil is used in a plethora of ways. Soil is where many of the nutrients plants need to grow comes from, soil purifies water, and even absorbs carbon dioxide from the atmosphere to be stored as carbon compounds (Miller and Spoolman, 211). Scientists study soil to develop a better understanding how this crucial factor in human’s survival functions and how to make sure humans don’t waste this precious resource (Miller and Spoolman, 211).
Effect of overburden pressure. Soils of same density will give smaller count near ground surface.
It is important to remember that the consolidation process is not the only one controlling the rate of the settlements in clay. Even when the excess pore water pressure has completely dissipated, different physical phenomena cause continued settlement. While this secondary compression is present from the beginning of the consolidation process, towards the end of primary consolidation its contribution
This paper reviews various methods used for the stabilization of the soil in the past. Papers summarizes the experiments done by the various researchers. As the soil weakness is the major cause of failure or degradation of structures standing on weak soil. A stabilized soil provides good contact between the foundation and the structure. The transfer of load takes place easily if the soil is stabilized. So the stabilization of soil is required and this paper enlightens some techniques and experiments which was used in the past and were found to be correct in increasing the shear strength of soil.
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.
The driving force, due to the weight of the soil, tends to move the soil mass down slope. The resisting force, due to the strength of the soil along the base of the soil mass, or “slip surface,” tends to hold the soil mass in place. If the driving force is greater than the resisting force, the soil mass will slide along the slip surface and a slope stability failure will occur. The potential for failure for a given soil mass is quantified in terms of the Factor of Safety, which is defined as the resisting force divided by the driving force. If the Factor of Safety is greater than 1.0, the soil mass will not
Management of soil is concerned with the ways of making the soil of better structure and quality. There are various methods employed by the farmers to do that-
A soil consists of an accumulation of particles which may be of a single mineral type, such as clean quartz sand, or more usually a mixture of a number of mineral types, each with a different particle density. The particle density of the solids comprising a mass of the soil is that of the mineral itself for a single mineral type. However, a soil consisting of a variety of minerals is mainly concerned with the mean particle density of the mass as whole, and this is the sense in which the specific gravity is used here. The concept of density is defined to mass per unit volume.
The soil profile is made up of layers called horizons. The thickness of horizons vary but they are usually parallel with the earth’s surface. Weathering of soil starts at the top and goes down so the most changed soil is the top layer and the deeper layers are more original to the parent material. Sometimes soil horizons stand out but other times it is hard to se...
Urbanization: Soil is considered as water reservoir. Urbanization acts in creating amount of impermeable surface due to construction of buildings, roads, drainage, sewage, flood relief channel etc. It reduces the amount of infiltration and percolation. Water tends to experiment the runoff process rather than infiltration. This contributes to increase in
Some soils have exceptionally good properties which is useful for plant growth and some soils are hard to cultivate. One of the major causes of tillage addiction is soil compaction also known as tillage pan.The intensity of tillage depends on the level of soil compaction. The huge mechanical stress applied to soil by powerful machinery is also an outcome of compaction. These forces lead to the loss of soil aggregates and pore spaces.