OCD59 UNIVERSITY OF BOLTON WESTERN INTERNATIONAL COLLEGE FZE BEng (HONS) IN CIVIL ENGINEERING SEMESTER ONE EXAMINATION 2016/2017 GROUND AND WATER STUDIES 1 MODULE NO: CIE4009 Date: Saturday 14 January 2017 Time: 10.00am -1.00pm INSTRUCTIONS TO CANDIDATES: There are FIVE questions on this paper. Answer ANY FOUR questions. Answer SECTION A and SECTION B on separate answer books. All questions carry equal marks. Marks for parts of questions are shown in brackets. This examination paper carries a total of 100 marks. Formula sheet/supplementary information is provided at the end of each section. All working must be shown. A numerical solution to a question obtained by programming an electronic calculator will not be accepted.
Page 2 of 18 SECTION A Question 1 (a) (b) With the aid of suitable equations briefly explain the difference between laminar and turbulent flow in pipes. (4 marks) For the measurement system shown in Figure Q1a, the pipeline and manometer fluids are water and mercury respectively. The densities are ρ= 1000kg/m 3 for water and ρ=13600kg/m 3 for mercury. If x = 0.75m and h = 1.2 m, find the pressure at Y in kn/m 2. (7 marks) (c) Figure Q1a. A pipeline 200 mm in diameter and 10 km long transfers water between reservoirs with water levels 350m AOD and 300m AOD respectively. Determine the flow rate between the reservoirs if the pipe material is having pipe wall roughness ks = 0.03mm. HRS Tables are attached on Page 4. (8 marks) (d) A trapezoidal canal has a bottom width of 3m and sides with a slope of 1 vertical to 2 horizontal. The depth of water is 1.2m when the discharge is 3.51m 3 /s. Calculate the slope of the channel bed using the Manning formula if Manning s Coefficient, n = 0.022. (6 marks) Total 25 marks Please turn the page
Page 3 of 18 Question 2 (a) A rectangular pontoon, 3m long, 1.5m wide and 0.8m high has a weight of 9050 N. The pontoon is located in sea water of density 1025kg/m 3 with its 0.8m sides vertical. The centre of gravity is at the geometric centre of the pontoon. Calculate the metacentric height and comment on the stability of the pontoon. (8 marks) (b) Briefly describe what is meant by frictional energy loss. Determine the loss of head due to friction in a cast iron pipe 400m long and 150mm in diameter which carries 43 l/s. Use the Darcy equation with λ = 0.02. (4 marks) (c) Water is discharged from a reservoir into the atmosphere through a pipe 100 m long. There is a sharp entrance to the pipe and the diameter is 75mm for 20m from the entrance. The pipe then enlarges suddenly to 150mm in diameter for the remainder of its length. A valve in the 75mm pipe has a kl = 1.5 when fully open. Taking into account the loss of head at entry, at the valve and at the enlargement, calculate the difference of level between the surface of the reservoir and the pipe exit which will maintain a flow of 10 l /s. Take λ as 0.02 for the 75mm pipe and 0.025 for the 150mm pipe. (13 marks) Total 25 marks Please turn the page for supplementary information for SECTION A
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Page 5 of 18 Formulae Sheet P gh Q AV 2 P1 v1 z ρg 2g 1 2 P2 v 2 z ρg 2g 2 hf hl h f 2 L v 2g d L Q 12.1 d 2 5 h h f L S 0 K L x L 2 v. 2g KL entry to pipe = 0.5 ; KL exit to pipe = 1 ; ( v1 v2 ) h L ( sudden exp ansion) 2g 2 Q A n 2 1. 3 R. S 2 o R A P END OF SECTION A Please turn the page for Section B
Page 6 of 18 SECTION B Question 1 (a) Give the particle size range for fine grained soils with its soil classification symbol. Discuss the concept of soil plasticity as it relates to fine grained soils. Ensure that your answer outlines why soil plasticity is important for civil engineering earthworks. (4 marks) (b) Describe how Standard Penetration Test results predict the geotechnical engineering properties when carried out in firm to stiff sandy CLAY and also in a medium dense coarse GRAVEL. Ensure that your answer states how the test results from an SPT test are written down and interpreted. (5 marks) (c) A constant head permeameter was set up contained coarse sand with an effective size D10 of 0.12mm. The timings required to collect 250ml of water were recorded at the following manometer readings. Determine the average value of k and compare this with Hazen s empirical relationship. The value for constant C, for coarse grained soils ranges from 0.008 to 0.015. The diameter of the sample and distance between the manometers are 100mm each respectively. Table Q1 (c) Time to collect Q 2 min 25s 3 min 15s 4 min 55s Manometer A reading (mm) 157 191 262 Manometer B reading (mm) 24 89 195 (6 marks) Question 1 continued over the page
Page 7 of 18 Question 1 continued (d) The results of a dry-sieving test on a soil sample of initial mass 217.4 g are given below: Table Q1 (d) Sieve size (mm) Mass retained (g) 3.35 0 2.0 2.5 1.18 12.5 0.60 57.7 0.425 62.0 0.30 34.2 0.212 18.7 0.150 12.7 0.063 13.1 Tray 4 (i) Determine cumulative percentage passing and plot the particle size distribution (PSD) on the chart provided in Figure Q1a on Page 8. (ii) Using the PSD curve, provide a soil classification NAME and symbol. (8 marks) (2 marks) Total 25 marks Question1 continued over the page
Page 8 of 18 Question 1 continued FIGURE Q1a Candidate Number. PLEASE ATTACH THIS SHEET TO YOUR ANSWER BOOKLET Please turn the page
Page 9 of 18 Question 2 (a) Sketch a Soil Model Diagram and show every term on your soil model diagram with the corresponding algebraic term for the respective mass and volume of the solids, water and air. (NOTE: Do NOT simply use the terms MA, MW, MS, VA, VW and/or VS). (2 marks) (b) Using the soil model diagram outlined in Q2(a) show the algebraic expression for the following soil properties ; (i) Bulk Density, ρb (ii) Dry Density, ρd (iii) Degree of Saturation, Sr (iv) Air Void Content, Av (NOTE: Do NOT simply use the terms M A, M W, M S, V A, V W and/or V S). (4 marks) (c) A container containing a sample of moist soil was weighed and had a mass of 37.82g; the empty container had a mass of 16.15g. After drying, the container and soil were weighed again and had a mass of 34.68g. Determine the void ratio of the soil if the air-voids content is (a) zero (b) 5 per cent (Gs = 2.7) (3 marks) (d) A specimen of clay soil was tested in the laboratory and the following data were collected: Mass of wet specimen, M1 = 148.8g Mass of dry specimen, M2 = 106.2g Volume of wet specimen, V = 86.2 cm² Specific gravity of soil, Gs = 2.70 Question 2 continued over the page
Page 10 of 18 Question 2 continued Determine: (i) Moisture content % (ii) Bulk Density, kg/m 3 (iii) Dry unit weight, kn/m 3 (iv) Void Ratio (v) Porosity (vi) Degree of saturation % (6 marks) (e) The results of a classification test conducted on a soil sample are shown below; Table Q2 (a) Plastic Limit Test Test 1 Test 2 Mass of empty tin (g) 20 21 Mass of tin + wet soil (g) 44 43.60 Mass of tin + oven dried soil (g) 39.15 39 Table Q2 (b) Liquid Limit Test Cone penetration (mm) 15.9 17.7 19.1 20.3 21.5 Moisture content (%) 32.6 42.9 51.6 59.8 66.2 (i) Using the data above and Figure Q2a on Page 11, as appropriate, determine the Index Properties for this soil. Ensure that you fully define what the Index Properties are for fine-grained soils. (8 marks) (ii) Provide a soil classification name and symbol for this soil using Figure Q2b on Page 12 (2 marks) Total 25 marks Question 2 continued over the page
Page 11 of 18 Question 2 continued FIGURE Q2a. PLEASE ATTACH THIS SHEET TO YOUR ANSWER BOOKLET Candidate Number. Question 2 continued over the page
Page 12 of 18 Question 2 continued FIGURE Q2b. PLEASE ATTACH THIS SHEET TO YOUR ANSWER BOOKLET Candidate Number. Please turn the page
Page 13 of 18 Question 3 (a) Desk study in Phase 1 of Ground Investigation is of paramount importance. The client should be encouraged to undertake a desk study to assess the site prior to specifying a Phase 2 ground investigation. Explain the significance of desk study and also state the comprehensive range of reference sources used for Phase 1 site investigation. (6 marks) (b) State why good quality soil sampling should be conducted. Briefly explain the two categories of soil samples and its application. (3 marks) (c) A British standard 2.5kg light compaction test on a soil sample (Gs = 2.70) gave the following results: Table Q1(c) Moisture Content (%) Bulk Density (kg/m 3 ) 5 1870 8 2040 10 2130 13 2200 16 2160 19 2090 (i) Using the data provided in the above table, plot the compaction curve on Figure Q3a on Page 15 to obtain the maximum dry density and the optimum water content. (8 marks) Question 3 continued over the page
Page 14 of 18 Question 3 continued (ii) Explain, by annotating your graph, how you would draw the 0% and 5% air voids curve on this graph (with the water contents 10%, 14% and 18%)and explain why it does not coincide with the Line of optimum. (6 marks) (iii) Estimate the air void content at the maximum dry density of the soil. (2 marks) Total 25 marks Question 3 continued over the page
Page 15 of 18 Question 3 continued FIGURE Q3a. PLEASE ATTACH THIS SHEET TO YOUR ANSWER BOOKLET Candidate Number. END OF SECTION B END OF QUESTIONS Please turn the page for formula sheet for Section B
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Page 17 of 18 8 9 10. Hazen s Formula, k = C.(D10) 2 Please turn the page
Page 18 of 18 END OF PAPER