Geomechanics Lab Report Essay Example

Geomechanics Lab Report Essay Example Geomechanics Lab Report Paper Geomechanics Lab Report Paper Aim The main intention of this investigation was to determine the various stages of the Attributer Limits. These included the liquid limit test (AL), plastic limit test (PL), plastic index test (Pl) and linear shrinkage (LS) of a soil sample provided by the administration. This was then followed by a sieve analysis to determine the particle size distribution of another soil sample so that a suitable classification in both situations could be made in accordance with the Australian Standards ASSAYS 1993. Procedure (Sample preparation) On commencement of the experiment, each group was provided with two arts of grammas of soil retrieved from the field and then oven dried by the experiment supervisor. One part of the soil sample was coarse grain gravel for the particle size distribution chart and sieve analysis, whilst the remaining 500 grams of soil was of fine grained fraction. * Preparation of Coarse Grained Fraction During this procedure the mass of grammas of soil was recorded and soaked in water for duration of 24 hours. This was then followed by placing the soil sample into a 0. Mm mesh sieve and the entire fine particle was washed away using running tap water and a small spray bottle until the water had started running Lear. The sieved sample was then transferred in a tray which was again put into the oven at 1 00 degrees for 24 hours. * Preparation of Fine Grained Fraction The remainder of the 500 grams of the sample was then sieved through a 0. 425 mm mesh sieve and the contents collected. This procedure was done until approximately 150 to grammas of material was successfully passing sieve. : Procedure (Sieve Analysis) This procedure involved the sieve analysis of the coarse fraction. This involved weighing the mass of the oven dried coarse grained fraction so that we are able to determine the particle size distribution. For this experiment the mass of coarse fraction used was 312. 10 grams. This was then followed by arranging the sieves from top to bottom in order from larger gaped mesh in the sieve to the smaller one (i. E. 37. Mm to 0. Mm) and then pouring the sample in the top sieve whilst shaking it for approximately 10 minutes. This provided mechanical energy to the soil allowing for it to pass all the sieve layers. The next procedure involved recording the soil mass that had accumulated on each sieve and the bottom pan. Furthermore the percentage of original mass retained and cumulative passing % vs Article size plot has been constructed as shown in Appendix A. As shown in the plot it can be noted that the results obtained were not accurate enough for the effective size values of D_II and D 30 to be calculated. Yet the effective size D 60 was able to be found and was shown to be 1. Mm as shown in the particle size vs.. Percentage passing table in appendix A. Due to the fact that all effective size values have not been able to be attained from the graph, the uniformity coefficient C_u and the coefficient of curvature were not able to be calculated. Yet if they could be then they would be calculated using these equations: u=DIODE where CUE=Coefficient of Curvature C=Coefficient of Curvature All values record ed have been further discussed in the results section of this report. Procedure (Attributer Limits determination) * Liquid Limit (AL) The liquid limit test west performed on the fine Sandy soil over the course of two sessions to determine the water content (percentage) at the point when the soil started to behave with liquid qualities. This test procedure involved gradually adding water to a round well created in two thirds of the soil sample on a glass plate. Then using two spatulas the sample was mixed until a smooth paste was formed. This was then followed by placing a small amount of the sample into the liquid limit device and leveling it horizontally using the spatula to create a smooth surface. Using the grooving tool the sample in the cup was divided in half. To determine the number of blows the handle of the mechanism was rotated at a speed of two blows per second and the number of blows recorded until the soil closed the groove to a length of 1 CM. It was expected that the number of blows be as close to 25+ or 3 as possible. The group was successful in our fourth attempt where 28 blows were recorded. Once the sample was successful it was removed room the liquid limit cup and placed within a tin and the mass weighed. This was determined to calculate the moisture content percentage. The mixture in the liquid limit range was placed in a 0. 25 meter length mould with a internal diameter of 0. 025 meters and left on top of the oven so that the linear shrinkage could be determined. All values obtained are discussed in the results. * Plastic Limit (PL) To determine the plastic limit (as a percentage), after which the soil could no longer be deformed; water was added to the remaining one third of the dry soil on a separate glass plate and molded by hand. Small amounts of the soil were rolled on the flat glass plate until they formed into a diameter of 3 mm and then started to break apart. According to SASHAYS it was proved that the soil had reached its plastic limit. This soil was then placed in a tin and similarly to the liquid limit all mass values of the tin and sample were recorded. These were left to dry in the oven. All results obtained the following day have been discussed in the results section. Linear Shrinkage (%) As instructed, results for the linear shrinkage were collected after duration of 24 hours from the laboratory and the linear shrinkage (in percentage) was lactated using the formula: where Ls=Recorded Shrinkage L=Lillian Length of Sample In addition to the linear shrinkage, all dry mass results were also collected from the previous day and recorded as shown in the results section of this report. * Plastic Index Conduction of the plastic limit and linear shrinkage test led to the calculation of the moisture content in percentage and this further allowed us to calculate the plastic index using the formula.