CVEN30010代写、代写Python、c++编程

日期：2022-09-20 01:26

CVEN30010 Geotechnical Modelling and Design (2022)

Lab Practical Instructions and Assignment Briefs

1. Introduction

The Lab Practical session is designed to facilitate the understanding of the

fundamental concepts of water flow in soils, which include the seepage phenomenon

and quicksand condition. A Cussons Technology permeability apparatus is to be

used in the experiment, as shown in Fig. 1. The experiment is to be conducted in

Francis Lab of Melbourne School of Engineering, located at mezzanine level, Block

D, Building 176.

Fig. 1 Test apparatus from Cussons Technology

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2. Experimental apparatus

As can be seen from the detailed components shown in Fig. 2, the apparatus consists

of a glazed aluminum tank supported on a steel frame, which is designed to contain

the permeable medium (e.g., sand). The front, back and sides of the tank are made

of clear toughened glass (giving scratch-free visibility without the risk of abrasion

of the inner surfaces).

Fig. 2 Components of the permeability apparatus

Fourteen piezometers are connected to the base of the tank with flexible tubes. The

spacing of piezometers is 120 mm as shown in Fig. 3. The left and right sides of the

tank accommodate seven piezometers each, to read the water head. These

piezometers are provided to allow measurement of head at various points along the

permeability tank.

Two removable end baffles are installed in the tank to retain the soil in the middle

part. Two header compartments are thus formed between the baffles and the two

ends of the tank. In the figure, the left compartment is the inlet, whereas the right is

the outlet. The water height in the testing tank can be adjusted and maintained using

the inlet and outlet header compartments.

A water sump tank equipped with a variable speed centrifugal pump acts as a source

of water supply. The water is circulated through the tank via header compartments

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at each end of the tank. Weir tanks piezometer is provided to measure the discharge

rate from the outlet head compartment located at the right-hand side of the tank.

Fig. 3 Schematic of the setup (for illustration purpose and not in scale)

3. Experimental setup

A sheet pile is fitted in the tank (which seals against the front and back walls of the

tank). Two tests were conducted, namely a seepage flow test with constant head

difference and a quick sand test with varying head difference. The first test is

designed to help you understand the concepts of flow nets through tracing the

seepage path and verify the theoretical formula based on Darcy’s Law. The second

is to observe quicksand (piping/ boiling) phenomenon, which helps you understand

the concepts of critical gradient and effective stress principle.

4. Experimental procedure

4.1 Test 1: Seepage flow experiment

(1) Start the circulation pump and adjust the speed to achieve a level of 450 mm in

the left-hand header compartment (inlet) with a steady but small flow in to the

overflow pipe. Adjust the height of the overflow to maintain a water level of

300 mm in the right header compartment (outlet).

(2) Maintain the constant head difference between the two sides of the sheet pile

as shown in Fig. 3.

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(3) Measure the dimensions of the tank, the hydraulic heads and sand level based

on a datum (e.g., the base of the sand). Record the hydraulic head at each

piezometer.

(4) Inject a shot of red dye into the sand away from the glass (approximately in the

middle) on the upstream side and observe where and how the dye reappears.

Please assess the type of the flow (laminar or turbulent) and give explanations

in your report.

(5) Inject a shot of blue dye on the upstream side against the glass. Make sure the

tip of the injection syringe is positioned just below the sand surface. Trace the

path of the flow line by marking the dye’s movement on the glass until the dye

reaches the ground surface on the downstream side.

(6) Repeat the above step at different spots on the upstream side to trace the flow

lines on the glass. Observe the change in velocity of the flow as it travels. Please

explain in your report how and why the velocity changes when the flow gets

closer to the sheet pile or leaves away from the pile. Did you observe the flow

lines intersecting each other? Please give your explanations.

(7) Measure the discharge rate at the water outlet using a beaker (i.e. measuring

cylinder) and a timer. Please convert this flow rate into litres per minute per

metre width of the tank.

In addition, the flow rate q can be calculated by using the following empirical

equation provided by the apparatus manufacturer:

= 0.001269?2.353/

where the flow rate q is in the unit of L/min and h is the head in the unit of mm

which can be obtained from the weir tank piezometer. Please calculate the flow

rate based on this empirical equation and convert this flow rate into litres per

minute per metre width of the tank.

(8) In your report, please sketch a flow net to represent the seepage flow in the

sand. Please draw it on the graph paper (with squares) provided in Appendix C.

Make sure the horizontal and vertical dimensions of your sketch are in same

scale. The photo of the experimental flow lines needs to be included for

comparison in your report.

(9) From your sketch of flow net, please calculate the discharge (litres per minute

per metre width of the flow net model) and compare your theoretical

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calculations with test results in step (7). The permeability coefficient of the sand

can be estimated from the Hazen’s Equation, k = 10 d2 , where k is in units of

mm/sec, and d10 is in units of mm (d10 can be estimated based on a particle size

distribution curve). Please find the particle size distribution in Appendix A.

(10) Based on your sketched flow net, please calculate the hydraulic head at each

piezometer. Compare the calculated results with the measured ones in step (3).

The numbering orders of piezometers in your report need to be consistent with

the experimental setup. Additionally, you are required to calculate the

theoretical hydraulic head at the positions marked with black dots (see

Appendix B) based on the flow net in step (8).

(11) Please analyse the discrepancies between the calculated results and test results

mentioned in step (9) and (10). Please give at least 3 reasons to explain it.

4.2 Test 2: Quicksand experiment

(1) The setup of this experiment is similar as that described in Section 4.1 except that

the sheet pile has a shallower embedment (to facilitate the occurrence of

quicksand).

(2) Instead of maintaining a constant head, gradually increase the hydraulic head

difference between the two sides of the test tank, until a quicksand phenomenon

occurs.

(3) Explain the phenomenon by referring to the change in effective stress in the soil

where quicksand occurs. Please give at least 3 methods to control seepage and

avoid the occurrence of quicksand.

5. GeoStudio modelling

You are required to model the experiment in 4.1 using the SEEP/W software and

compare the model outputs with your hand calculations and the experimental results.

Please include sufficient evidence (i.e. geometry, material, boundary conditions and

results) from the SEEP/W outputs such as screenshots of the results to support your

interpretation and analysis.

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6. Report requirement

Lab Practical Report will be assessed individually. Students are required to prepare

the report based on your own experimental data. For students attending the

practical remotely (i.e. online session P6), your experimental data will be provided

separately.

1. Your report should cover all the tasks above.

2. Your report should contain cover, content, seepage flow experiment,

quicksand experiment and SEEP/W modelling. There is no need to repeat the

experimental setup and procedures.

3. Page limit: 6 pages, single spacing, size 12 font. Page limit includes

everything in your report. If your report is beyond the 6-page limit, only the

first 6 pages will be marked.

4. If you have any question, please post it on the Discussion board under the

section of “Discussions on Lab practical”. Remember all technical questions

must be asked on the Discussion board and will not be answered when sent to

personal emails.

5. For Lab Practical related non-technical issues, you can contact Zeliang Li

(zeliangl@student.unimelb.edu.au). Please include ‘CVEN30010’ in the

subject line in your email and remember emailing is for personal issue only.

6. A one-hour online consultation session is scheduled on 4:00 pm Monday in

Week 8 (12th September). Please see Canvas->Zoom for further information

on the meeting.

The due date for submission of the laboratory report is 11:59 pm on Sunday 18

September 2022. Your report should be submitted electronically via the submission

link in Canvas, which will be opened and announced in Week 7. Submissions

through email will NOT be accepted. Please note late submissions incur penalty of

20% per day.

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Appendix A: Sieve analysis result

Table 1 Sieve analysis result