HNCB43 Hydraulics for Civil Engineering - Higher National Certificate/Diploma in Construction and the Built Environment
Learning Outcome 1: Apply concepts of physics to develop solutions to hydrostatic and hydrodynamic problems
Learning Outcome 2: Calculate forces related to fluids at rest and in motion
Learning Outcome 3: Develop practical solutions for the distribution of fluids within correctly sized pipes
Learning Outcome 4: Calculate the hydrostatic pressure exerted on substructures for a given context
Assignment Brief
Scenario A mine has to wash certain impurities out of the ore one of which is highly toxic before it is sent to the processing plant. The water needs to be stored in a pond which is emptied every hour of the day with a 28 m3 road tanker where it is transported to a chemical treatment plant. The mine works for twelve hours a day and it produces 50m3 per hour of toxic waste water.
Task 1
Discuss a) the size of the pond that is needed allowing for possible interruptions of the tankers' timetable
b) discuss the possible design of the pond either
i) using very expensive concrete which is totally waterproof or
ii) using a different kind of waterproof lining to prevent seepage such as a heavy gauge plastic liner or
iii) using locally available clay
c) what inspection system would be used to check for seepage?
d) Some other factors to consider the road to the mine is an unmade narrow winding road and below the road and the mine is a small town where most of the miners and their families live there is often ice on the road in winter and the surface of the road deteriorates during heavy rain
The families are very worried about pollution from this wash water and road traffic accidents and have asked that an alternative arrangement be made by laying a pipeline to a new pond which would be situated near to the main highway alongside the existing ore transporter belt which would provide a much more secure access to the water needed for treatment
Discuss possible solutions and choose one which you will illustrate.
LO2 Calculate forces related to fluids at rest and in motion
Task 2 a) In the above scenario use Darcey Weisbach equation to calculate the minimum pipe diameter given the following information. The distance between the mine and the main highway is 10km. The height of the mine is 250m above datum and the height of the main highway at the nearest point to the mine is 125m above datum. You may assume that the Darcey Weisbach friction f value is 0.01
b) Would the pipe be laid on the surface or dug into a shallow trench? Discuss the advantages and disadvantages of each and reach a conclusion as to what choice you would make
c) What happens if the flow is not enough to completely fill the pipe? Assume that the pipe has a diameter 0.5m and is carrying 50m3per hour and the slope of the pipe is determined by the difference in height between the start and end of the pipe, and the length of the pipe, what would be the mean velocity of flow assuming that the pipe was made of smooth plastic (you will need to look the friction up) The height of water is 0.4m and the calculation of the hydraulic radius is best done using the online calculator at Hydraulic Radius Calculator | Wetted Perimeter (omnicalculator.com)
d) discuss the differences between a full pipe flow and a partially full pipe flow.
LO3 Develop practical solutions for the distribution of fluids within correctly sized pipes
Task 3
a) Using this same scenario the detoxification plant is some 25km away from the mine and a further development was to examine the possibility of a pipeline going directly into the detoxification plant. It is also a further 50m down towards the datum point. Calculate what the maximum head loss could be provided so that the only force moving the water was gravity. Now check that a pipe of 0.18m diameter would be sufficient to move the required waste water. Assume that the Darcey Weisbach friction is 0.01.
b) The mine owners would like to open up 24/7 working which would at least double the amount of toxic waste the would need to be treated. How would this affect the minimum pipe size? Prepare a graph of Pipe diameter for a range of waste arisings from 0.01 to 0.06 m3/second which would advise the mine owners of the feasibility of their proposal
Task 4
a) At the treatment plant they would prefer to do batch treatment of 400m3 of toxic washings at a time. The proposal is to store the waste in a reservoir with a dam at one end so that there is a head of at least 10m of water which will then push the waste through the system without any mechanical assistance so the location of the reservoir will be at the highest point of the treatment station and the treatment would be carried out in the main process area situated 20m below. The reservoir would be 10m above the process area. There is only room for a reservoir 8m wide and 25m long. At any one time there could be up to three days delivery of toxic waste stored there when the mine is working 24/7 (24 hours a day 7 days a week) Three sides of the reservoir are built into the surrounding hill but one side of the reservoir is a boundary wall. What is the total force exerted by the waste water on the wall? Assume that the density of the water is 1000kg/m3
b) The treatment room is situated directly underneath the floor of the reservoir, what is the total load on the treatment room ceiling?
Attachment:- Hydraulics for Civil Engineering.rar