Analysis of Soil Samples Collected in the Berth Region - Research Paper Example

ENS1234Unit Progress Report My Project John Citizen # 12345678 26 May Supervisor: Dr Jane Public The aim of this project is to carry out a comprehensive analysis of soil samples collected from some four different sites in the Berth region: Yanchip, Swan valley, southern River, and Scarborough Beach. In this paper, the methodology that has been used to conduct the analyses will be achieved by conducting several tests including sieve analysis, performing the relative density tests, testing for the angle of repose and finally carrying out a permeability test. The results for the three tests are available and only the test for permeability remains to be conducted. After we have conducted and analysed our tests, a risk management procedure is going to be carried to determine the possible risks that may occur during these tests and finally propose measures that can be taken in order to minimize the risk. Table of Contents 1. Abstract................................................................................................2 2. Introduction...........................................................................................4 3. Testing methodology..............................................................................6 4. Risk assessment.....................................................................................26. 5. Conclusion............................................................................................28 6. References...........................................................................................29 1.0 Introduction 1.1 Introduction Soil is a very fundamental resource that is very crucial in the agricultural industry and more so the engineering sector in building and construction. This plays a very important role in the general economy. Soil has various components that normally play a very crucial role in ensuring that the plant growth occurs in a healthy manner, the regulation of drainage and flow of water is also maintained which is very crucial in engineering and construction. Perth region is located in the coastal plains of Swan a region whose geology is characteristic of sedimentary rocks. The soil samples were collected from four areas: Yanchep, Swan valley, southern River, and Scarborough Beach. In each location, a sample of 100kg of soil was collected for testing in the laboratory and subsequent analysis would follow the test results. This helps to determine the engineering behaviour of soils in the Perth region. Figure 1: The geographical location of Perth 1.2 Objectives The aim of the project is to determine the engineering properties of soils in the Perth region based on an analysis of the soil samples collected from four different places which are Yanchep, Swan valley, southern River, and Scarborough Beach. The main objectives are outlined below. 1. To determine the properties of soils in the field of engineering. 2. To analyse the factors that affect and influence the characteristics of the soil. 3. To come up with behaviour for soils this can be solved using the four methods identified in the experiment. 4. To do a comprehensive analysis of the data on the four methods and finally compare the numbers obtained from the experiments. 1.3 Significance The tests for soils engineering behaviour are very important in the field of Geotechnical engineering. The properties of soil such as compactness, compressibility, permeability and shear strength help Geotechnical engineers to evaluate the stability of natural slopes and manmade deposits. They are able to make a comprehensive assessment to risks in different engineering sites and hence designers are able to make the most appropriate structures suitable for a particular site. In this report we shall illustrate the different methods applied in soil testing and analysis giving the areas of application of each behavioural property of a particular type of soil. 1.4 Report Organisation The progress report consists of seven chapters whereby each illustrating a comprehensive approach to soil analysis. The different methods are discussed between chapter 1 and chapter 4 while the rest gives a summary of the discussions, risk assessment and the sources where this information was obtained from. a) Chapter 1 introduces the method of sieve analysis that is used to determine the relative proportions of the grain sizes of various soil samples and the procedures and results of this method are discussed in details. b) Chapter 2 presents the tests for relative density of a soil sample giving a description of the method, the equipments required, the procedures used for this method and finally the results obtained. c) Chapter 3 addresses the test for the angle of repose in a comprehensive way showing all the procedures, materials used and the expected results. d) Chapter 4 describes the test for permeability and gives an overview of the methods that will be used to conduct this test. e) Chapter 6 focuses on risk management and proposes remedies to minimize the chances of the risk involved. f) Conclusion can be found in Chapter 7 and gives a summary of the discussed methods. 2.0 Background Soil is a very fundamental resource for the agricultural industry as well as the building and construction sector and the general economy. Soil has very important engineering behavioural properties that are used by Geotechnical engineers to make a proper analysis of the suitability of an area taking into consideration the determined properties. Mamlouk and Zaniewski (2009) in their in their publication, Materials for civil engineering, take a critical approach on their analysis of soil as an engineering material, they observe that soil has a wide range of behavioural properties that can be used to solve a number of environmental problems that are related to geology, the stability of soil in settlement areas and the drainage problems in different terrains. In engineering works, soil testing is of great importance as it helps to determine the composition of the soil sample as well as the behavioural properties that are of critical importance to the field of engineering. The western Australian region where Perth is located in the coastal plains of Swan a region whose geology is characteristic of sedimentary rocks and the soils have a high percentage of sand in them (MacArthur et al.). The soil samples were collected from four areas: Yanchep, Swan valley, southern River, and Scarborough Beach. In each location, a sample of 100kg of soil was collected for testing in the laboratory and subsequent analysis would follow the test results. This test will be very crucial in determination of the engineering behaviour of the soils of the four regions. 3.0 Proposed Approach The approach in determining the behaviour of soils in Perth will be achieved through a number of analysis tools and methods which include: sieve analysis, measuring the relative density, tests for the angle of repose as well as carrying out permeability tests. The actual procedure entailed taking soil samples in four different locations within Perth region of subjecting the soil samples to various tests and analysis methods in order to determine their composition, properties and engineering behaviours. Tests have already been carried out to determine the characteristics including: sieve analysis, testing to determine the relative density of the soil the soil, testing for the angle of repose as well as testing for the permeability of the soil. 4.0 Preliminary Results and Discussions Chapter 1 Sieve analysis Sieve analysis and standard grain size analysis of the soil samples collected from the four different sites in the Berth region was carried out to determine the relative proportions of the grain sizes of the different soil samples that were collected. For the tests, we shall need the following apparatus a) Balances with limits of performance b) Sieves to determine the suitable sizes complying with AS 1152. c) An oven complying with AS 1289 is thermostatically controlled to operate at 1050C to 110oC. d) Sample dividers of appropriate size openings. e) Dishes and trays. f) Sieve brushes and a wire or other stiff brittle brush. g) Reinforced 75 µm washing size. h) Mechanical sieve shakers. i) Mechanical dispersion apparatus. Reagents Sodium hexametaphosphate dispersing solution prepared by dissolving either 33grams of haexametaphosphate with 7g of anhydrous sodium carbonate or 18.9 grams of hydrated sodium carbonate in distilled water to make 1000ml of solution. Procedure First we must separate the soil sample that we have into a number of sizes as required using the necessary sieves to obtain the desired specimen such that we have: coarse grained specimen, fine grained specimen and intermediate specimen. Next conduct the process of sieving in the three stages identified such that you will be working with three samples of the soil: coarse grained, intermediate soil and fine grained soils. It is a common practice in this test to use the 19mm and 2.36mm sieves to separate the coarse and intermediate sieve analyses the intermediate and the fine sieve analyses respectively. Sieving may be done by use of hands or by use of mechanical shakers. The materials that are retained in the 19mm or any other larger sieve is manipulated and sieved by hand. If sieving is manipulated by hand, it is important that we keep the sample moving in a continuous manner over the surface of the sieve. This can be achieved by using a lateral and a vertical motion accompanied by a jarring action. One should continue sieving until the mass passing through the sieve every minute is reduced to less than 1%. Care should be taken not to overload the sieves as this may damage them and affect the accuracy of the results. Table1: Some common sieve sizes Sieve no. Size in mm 4 4.75 10 2.00 20 0.841 40 0.420 70 0.210 100 0.150 200 0.075 Results and analysis The results of the mechanical analyses are presented by logarithmic plots known as particle distribution curves. The use of a logarithmic graph allows better visualization of data that are changing with an exponential relationship. The advantage of this method is that it can bring out features in the in the data that would not easily be easily seen if both variable had been plotted linearly. Figure 2: particle distribution chart for the results obtained from the sieve analysis test. Calculations Some important tests were conducted and the results are calculated below: From the distribution curve we can determine the following: a) Effective size of the soil particle. b) Uniform coefficient of the soil. c) Coefficient gradient. To calculate the uniform coefficients for each soil sample: Soil 1 This soil sample was gathered from Southern River From the graph, we the following information can be extracted: a) The amount of fine grains is lesser than the coarse grains. b) The intermediate grains take the highest percentage of the entire soil sample. This means that this soil is not capable of holding alot of water. D10=0.16 D30=0.175 D60=0.25 Soil 2 This soil sample was extracted from Swan Valley. The following details can be extracted from the graph: a) The curve starts at approximately 7% of the weight of the soil sample and moves in a smooth way. b) The percentage of fine grains in the soil sample is less than intermediate grains in the sample. c) This means that the soil has very good engineering behaviour. D10=0.17 D30=0.25 D60=0.5 Soil 3 This soil sample was obtained from Scarborough. From the graph, the following information can be deduced: a) It starts at approximately 4% and moves from the finest in smooth curve. b) The percentage composition of the coarse grains, intermediate grains and fine grains is almost the same. D10=0.18 D30=0.6 D60=0.80 Soil 4 This soil was obtained from Yeachap area. From the graph of soil 4, we can gather the following information: a) It starts from approximately 1% of the weight of the soil. The percentage of fine materials drops to zero as a result of the reduction in the amount of fine materials. b) The curve is smooth and the rate of change is changing constantly. c) We can conclude that the amount of finer grains is lower than the amount of intermediate and coarse grains. Therefore, the soil sample retains very little amount of water. D10=0.00 D30=0.6 D60=0.75 In this method of soil analysis, there is a possibility of errors accumulating leading to inaccurate results. Errors may result from factors such as loss of some sediments of the soil sample during the process of sieving, inaccurate readings accumulated through human error and evaporation of water during the experiment due to the changing temperatures within the lab. Errors related to inaccurate reading of results may be cumulative in nature leading inaccurate results. However, they are parameters that have been set in this method to take care of these shortcomings such that the results obtained are free from ruggedness, bias and they have a degree of precision in them. Chapter 2 Test for relative density In soil geology and mechanics, relative density is defined as the ratio between the maximum index void ratio and field void ratio of a free draining and cohesion less soil. During the analysis, the determination of the relative density of the soil samples was of great importance in evaluating the engineering characteristics of the soil samples from the four regions of the Perth: Yapchen, Swan valley, southern River, and Scarborough Beach especially in reference to the compactness characteristics of the soil as this is a major factor in determining the stability characteristics of the soil. After we have conducted the relative density test, we shall be in a position to determine some very fundamental engineering properties of the soil samples including: the compressibility properties, the shear strength and permeability of the soil. As indicated earlier, these properties a dependent on the compactness of the soil and this plays a major role in engineering works. Relative density of the soil is the ratio expressed as a fraction and therefore we must determine the greatest index void of the soil. In this case, we are going to use the relative density obtained from the test together with the compacter to determine the state of compactness of the soil. Apparatus To conduct the test, the following apparatus were needed: a) A vibrating table and molding assembly composed of standard mold. b) Guide sleeves. c) Surcharge base plate. d) Surcharge weights. e) Surcharge base plate handle. f) Dial indicator gauge. g) Balance scoop. h) Straight ledge. The following reference standards will be adhered to in this test. 1) ASTMD 4254-Standard Test methods for minimum index density and unit of soils and calculation of relative density 2) ASTMD 4253-Standard test methods for maximum index density and unit weight of soils using a vibratory table. Results and analysis In the analysis of the results, the following parameters must be determined as they are very crucial in determining the compactness characteristics of the soil. ) . The results for the relative density are presented in the chart below. Figure 3: Distribution curve showing the results for the relative density Chapter 3 Test for the angle of repose The ISO definition for the angle of repose is the baser angle of the cone obtained by the flow of water under specified conditions. The soil material on the slope surface is on the threshold of descending at an angle. It can range from 0o-900. The test determines the load carrying capacity of soils, stability of slope and pipe capacity. It is obtained frictional resistance component, cohesive component, and shear stress strain characteristics. The angle of repose can be used in the design of equipment for processing particulate solids as hoppers, silo and conveyor belts for transporting the material. It also evaluates whether a slope of uncompacted gravel bank will collapse. Apparatus a) Glass funnel agitator comprising of two rods b) Base plate c) Transparent plastic vessel d) Funnel support e) Supporting rod f) Graduated measuring cylinder. Procedure In order to determine the angle of repose of the cone, the volume of the product is passed through the cone in the form of powder or granules. A special funnel is placed at a fixed height above a completely flat and level plate. Figure 4: an illustration of the setup of a repose test apparatus Results and analysis The results obtained from the test for the angle of repose are recorded in the table below. Table 2: The results obtained from the test for the angle of repose. column Height A Height B Height C Height D Height E Soil 1 35.82mm 33.52mm 35.30mm 35.05mm 34.34mm soil 2 36.85mm 36.90mm 37.39mm 36.81mm 37.29mm soil 3 33.05mm 33.13mm 33.02mm 3470mm 35.47mm soil4 37.49mm 36.95mm 37.40mm 37.74mm 37.87mm soil 1 - Southern River soil soil 2 - Swan Valley soil soil 3 - Scarborough soil soil 4 - Yeachap soil Height average Angle D10 D10 soil 1 34.81mm 34.84 degree 0.2 0.26 soil 2 37.05mm 36.54 degree 0.2 0.36 soil 3 33.87mm 34.12 degree 0.19 0.22 soil 4 37.49mm 36.86 degree 0.12 0.19 Using the formula above: The angle of repose was determined for each location. Table 3: Results for the angle of repose Location Angle of repose soil 1 - Southern River soil 34.84 degree soil 2 - Swan Valley soil 36.54 degree soil 3 - Scarborough soil 34.12 degree soil 4 - Yeachap soil 36.86 degree Figure 5: graph of high height against the weight of soil collected. Figure 6: Linear graph of weight of soil ample collected for the four locations versus the high values of soil Table 3: Repose test weight analysis results for the four locations.   cm 0 10 20 30 40 50 Soil 1 Yanchep 1175.9 1201 1204.8 1212.8 1225.4 1221.5 Soil 2 Southern River 1522.1 1546.7 1555.7 1561.7 1577.1 1574.7 Soil 3 Swan Valley 1464.5 1496.9 1508.5 1523.1 1526.2 1520.7 Soil 4 Scarborough Beach 1388.5 1401 1415.9 1432.5 1435.9 1441.9 Chapter 4 Test for permeability This is the last part of the project whose tests is yet to be done hence the results are not available for analysis. According to the project timeline, the test for the permeability will be carried out sometimes next semester. The test for permeability is used to determine the hydraulic conduction of soils. The properties of soil determined so far can be classified as either physical or mechanical properties as shown in the tree diagram below. During the test, a known constant pressure through the sample of known dimensions forcing water and the rate of flow can be determined. The test primarily determines whether sand and gravel soils are suitable for drainage purposes. The constant head test method and the falling head test method are the commonly used tests for permeability. The slope created during the test is used to measure the rate at which water flows through the soil. Water is forced by a known constant pressure through a soil specimen of known dimensions and from these details, the rate of flow can be determined. 1. Constant head test It is used on samples that represent materials that are to be used as backfill for abutments, as permeable materials for underdrain, materials for sand drains as well as sand blankets foe. The constant head test is based on the assumption of a laminar flow of water in the soil. In this test, as a rule of thumb, the ratio of the cell diameter of the largest grain should be greater than 12 (Head 1982). Figure 7: An illustration of the set up of a simple constant head test. Calculations involving the constant head test. 2. Falling head test Falling head test is used to determine the drainage characteristics of relatively fine grained soils and is usually performed on soil samples that are generally undisturbed. It is applicable for both coarse grained soils as well as fine grained soils. The test is of particular importance in analysis of seepage characteristics of water through porous materials. Permeable materials have continuous voids within their structure and are therefore able to permit passage of fluids through conditions that are interconnected to one another. The principle of the falling head is the Darcy’s law for laminar flow which states that the rate of laminar flow is proportional IA In this test it is assumed that the soil remains constant during the test (soil should be completely saturated and hence have a steady laminar flow condition). Figure 8: Illustration of a set up of the falling head test Calculations involving falling head test Coefficient of permeability can be calculated as: Application of the permeability test The permeability test conducted on the soil samples is very important in: a) Estimation of the quantity of underground seepage. b) Solving of problems that involve pumping seepage of water from construction excavation sites. c) The stability analysis of earthwork structures and retaining walls that are usually subjected to seepage forces. An example of such a structure is a dam. Chapter 5 Risk Assessment While working with the equipment and reagents necessary for these tests, one is prone to several risks that may arise during the experiment. There is need to analyse the possible risks that can come up and propose the possible solutions to these risks. Most of the risks have been rated as either being medium or low and hence there is no possibility of them resulting in a catastrophic accident. However, there is need to come up with solutions to these risks to avoid any harm happening to the people working on the project. Using a decision matrix we shall analyse the level of risk in a comprehensive way and propose possible solutions to these risks. Figure 9: Decision matrix for the risks involved and the possible solutions task criteria Hazards Level of risk Control Vibrating machine Eyes, hands and body injury Medium Make sure that the machine is turned off before putting on the sample. Make sure that the nuts and bolts are tight before turning on the machine. Keep distance when the machine has been put on. Vibrating table for density Hands, upper body injury, feet injury and lung problems Medium Make sure that you have protective clothing both ob your hands and feet. Make sure that you put on goggles before operating the machine. Make sure that you put the sample carefully on the machine. Shear test machine Hands injury, feet and fingers Low Keep your hands and feet away from the machine Constant head Feet injury and upper body injury Low Make sure that you make the slippery spots on the floor Electrical machine Electrical shock medium Make sure that there is no water close to the machine. Make sure that the machine is plugged in properly. While conducting the tests in the lab, it is advisable that everyone working on this project should be dressed in the right protective clothing to avoid any harm. Proper shoes should be worn together with gloves in the hands when handling the apparatus. Conclusion In conclusion, determination of soil composition, properties and behaviour of a given area is of great importance in solving problems related to environmental impacts and related to geology, soil settlement and water flow among others. Although there are a few risks involved in the soil testing and analysis, the project risk assessment has shown the average risk involved in the project is medium. A number of control measures have been proposed to help minimize the risk levels during the course of the project. The methods used to analyse the engineering behaviours of the soils have been effectively used to determine the suitability of soils and the final test for permeability is expected to help determine the most appropriate soil foe engineering related activities. References Wyrwoll, K. (2003). The geomorphology of the Perth region, Western Australia. Australian Geomechanics, 38(3):17–32. Carbon, B.A. 1973. Some aspects of soil-plant water relations in a coarse soil. MSc Thesis, University of Western Australia. White, R.E. 1997. Principles and Practice of Soil Science: The Soil as a Natural Resource. 3rd ed. Blackwell Science, Oxford. Topp, G.C., Galganov, Y.T., Ball, B.C. and Carter, M.R. 1993. Soil water desorption curves. In: Carter, M.R., ed., Soil Sampling and Methods of Analysis. Lewis Publishers, Florida: 569–580. McArthur, W.M. and Bettenay, E. 1960. The development distribution of the soils of the Swan Coastal Plain, Western Australia. Soil Publication No 16, CSIRO, Melbourne. Ahmed, M., Sharma, M.L. and Richards, Q.D. 1996. Evaluation of field sampling methods for soil water quality. Aminuddin, B.Y., Sharma, M.L., and Willett, I.R., eds., Agricultural impacts on groundwater quality. Proceedings of an international workshop held in Kota Bharu, Kelantan, Malaysia, 24–27 October. A C I A Proceedings No 61. Sharma, M.L., Herne, D.E., Byrne, J.D.M. and Kin, P.G. 1995. Leaching of nutrients beneath urban lawns to an unconfined sandy aquifer. CSIRO Division of Water Resources Report No. 95-12, 111pp Mitchell, J., Hooper, D. (2005). Permeability of Compacted Clay. Journal of Geotechnical Engineering, ASCE 91, 4, 41-65 Mamlouk, M., Zaniewski, J. (2009). Materials for Civil and Construction Engineers. Menlo Park CA: Addison-Wesley. Gee, G.W. and Bauder, J.W., Particle-size analysis in Klute, A., ed., Methods of soil analysis part 1 : physical and mineralogical methods, American Society of Agronomy-Soil Science Society of America, Madison, WI, 1986. Soil Survey Laboratory Methods Manual : Soil Survey Investigations Report No. 42, United States Department of Agriculture - Natural Resources Conservation Service - National Soil Survey Center, 1996. Joseph E. Bowles, Engineering Properties of Soils and Their Measurement, McGraw-Hill Book Company, New York, 1970. T.William Lambe, Soil Testing for Engineers, John Wiley & Sons, Inc.,New York, 1951. Karl Terzaghi and Ralph B. Peck, Soil Mechanics in Engineering Practice, 2d ed., John Wiley & Sons, Inc., New York, 1967. Soil Survey Laboratory Information Manual, 1995: Soil Survey Investigations Report No. 45, United States Department of Agriculture - Natural Resources Conservation Service - National Soil Survey Center. Dr Anand J Puppala, Lecture notes, Determination of coefficient, The University of Texas at Arlington of permeability of sand by constant head soil mechanics laboratory, Read More