Plastic Limit It is defined as the water content at which a soil would just start to crumble when rolled into a thread of 3mm diameter. Procedure (Acc. to IS:2720 part 5) i) Take about 8gm of the soil and add some known quantity of water starting from lower value, if thread is broken add some more known quantity of water and repeat the process. roll it with fingers on a glass plate. The rate of rolling should be between 80-90 strokes per minute to form a diameter of 3mm.
Results and Discussion: 1. Variation of Swelling (Murram soil) • Free swelling test was performed on Raipur soil by successive increment of percentage of gypsum by weight. • Gypsum was added to the soil by 2, 4, 6, 8 and 10% by weight. It was noted that increase in gypsum content increases the swelling of soil. Table 1 Variation of swelling of Murram due to increase in gypsum content Gypsum content (in %) Swelling in water Swelling in kerosene Initial Final Initial Final 0% 11 12 11 11 2% 11 13 11 11 4% 11 13 11 11 6% 11 13.5 11 11 8% 11 14 11 11 10% 11 14 11 11 2.
Fig. 22.214.171.124 Casagrande’s Liquid Limit Apparatus Plastic limit is the boundary condition of moisture content after which soil in plastic state changes to semi solid state. The purpose of determination of plastic limit is defined as the moisture/ water content at which soil will just begins to crumble when rolled into a thread of 3mm in diameter. For plastic limit 15g of oven dried soil passes through IS 0.425 mm sieve and mixed distilled water thoroughly until soil mass becomes plastic enough to be easily moulded in a ball with fingers and takes its portion of ball and rolled it on a glass plate with the plam into a thread like structure. The thread should be in a uniform diameter and length till it covers around 3mm diameter.
Soil and its origin Soil is the unconsolidated mineral or organic material which forms the outer loose layer of earth surface that serves as a natural growth medium for land plants. Soil originates from disintegrated rock materials. These rocks could be igneous, sedimentary or metamorphic. The simultaneous and continuous weathering of rocks by physical and chemical elements results in formation of parent materials. The action of biosphere (Living components of soil) on the parent materials forms soil.
For a soil in its densest condition, its void ratio is the lowest and it exhibits the highest shear strength and the greatest resistance to compression. Porosity of a soil depends on the shape of graind, uniformity of grain sizes and condition of sedimentation. Hence porosity itself does not indicate whether a soil is in a loose or dense state. The compactness or denseness of granular soils can be evaluated quantitatively by the relative density (D_r). Relative density or density index is the ratio of the difference between the void ratios of a cohesionless soil in its loosest state and existing natural state to the difference between its void ratios in the loosest and densest states, Adeyeri (2015) and is defined
Vegetation located in prairies, forests, and other natural areas also plays a similar role. The surface of the soil works as a filter that allow water pass through at a certain rate which known as the infiltration rate or infiltration capacity. A runoff may be created when precipitation deposits water to the soil surface quicker than it can be absorbed. The excess water stays on the surface and flows downslope as runoff. If the rate of precipitation is 5 centimeters per hour, but the rate of infiltration is only 2.5 centimeters per hour, surface runoff is produced at the rate of 2.5 centimeters per hour, even if the soil is not entirely soaked.
Groundwater exceeding the limit of 300 mg/l is considered to be very hard (Sawyer and McCartly 1967). In the study area 6.45 % and 93.55% (Table 3) of the samples fall in the water type of hard and very hard type respectively. TH ranges from 212 to 3,600 mg/l with the average value of 777 mg/l. The spatial distribution of the TH is shown in Fig. 6.
Lab Report #3: Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/ft3 (600 kN-m/m3)) Soil compaction demonstrates how the soil will behave considering factors such as physical and chemical properties, moisture content, method of compaction, amount of compactive effort, and thickness of layer or “lift” being compacted when a compactive effort was added to it. This results to a compaction curve which is a plot of dry density versus moisture content. This was obtained by compacting moist soil with prescribed added amount of water in a compaction mold and getting the moisture content of a subspecimen retrieved from the center of the compacted mixture. The peak of the curve is a point showing the optimum moisture
4. Result and Discussion According to the Lithofacies, Electrofacies, and Litostratigraphic correlation, there are at least six main facies namely: (A) Calcareous siltstone in the depth of 1565 – 1574 meters, (B) Silty shale in the depth of 1574 – 1588 meters, (C) High burrowing very fine sandstone in the depth of 1595.0 – 1600.35, (D) Fine sandstone with slight mud drapes in the depth of 1600.35 – 1603.55 meters, (E) Organic Shale in the depth of 1603.55 – 1604,95 meters, and (F) Very fine sandstone to intercalated siltstone and shale in the depth of 1604.95 – 1608.35 meters. The Litostratigraphic Correlation can be seen in figure 3. Figure 3: Litostratigraphic Correlation The volume of shale was calculated to determine the amount of shale