The Bang Lang dam is one of the major hydro dams in Thailand

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The Bang Lang dam is one of the major hydro dams in Thailand

Question # 00104243 Posted By: echo7 Updated on: 09/17/2015 01:57 PM Due on: 10/17/2015

Subject Engineering Topic General Engineering Tutorials:

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Assignment 4. Interpretation and analysis of geotechnical data

Due date:17 June (week 15)

Submission:Safe-Assign online submission

Learning objectives: This activity will provide students with opportunities to develop critical skills necessary to correctly interpret and analyse results of field and laboratory investigations and demonstrate the skills needed to produce comprehensive and concise reports.

Weight: 25%.

Group A: You are in this group if the first letter of your family name is in the range from A to K (including).

Task description: The Bang Lang dam is one of the major hydro dams in Thailand. After its completion, the neighbouring slopes began to experience some slope stability issues during rainy seasons. An underground spillway tunnel was then considered to avoid any risk associated with slope instability. Field investigations, including geological mapping and joint survey, and laboratory testing were performed to collect more information regarding the properties of rocks in that area. The obtained data are presented below in the forms of maps, borehole logs, and the results of laboratory tests.

Your task is to interpret andanalyse the obtained results and

- draw a cross-section of the slope and identify the major geological units;

- for each geological unit,when possible, determine the strength characteristics of rocks and rock mass including the unconfined compressive strength of rocks/rock mass, shear strength of jointed rocks, and the friction angle of rocks/rock mass;

- determine the rock mass rating (RMR), and characterize the properties of the rock mass.

You need to present and discuss your findings in the form of a report (max 10 pages, excluding references and appendix).

Report structure (optional):

1. Introduction (What is the problem? What is the objective? Based on the data provided, what investigation was performed?).

2. Description of thestudy area.

3. Interpretation and analysis of the data(you need todraw a cross-section and discuss the properties of rocks which are given in the bore logs)

4. Summary and conclusions (you may also include some recommendations regarding the preferable location of the tunnel).

5. References (if necessary).

6. Appendix (if necessary).

Note:Maximum 10 pages (excluding references and appendix).

You need to provide a cross-section in your report.

No plagiarism.

Late submission will be penalised (1 day = -10 points).

Marking criteria

Minimum Standard.

Report Structure. The document is written in a clear and concise manner and includes most of the elements that would be expected in this report. The majority of the section headings appropriately describe the information provided within the text. The majority of the text is written as a clearly structured narrative and is organised in a logical manner. The report provides an acceptable level of description of the project and its outcomes within the set page limit.

Effectiveness of Presentation. Although the document may contain some spelling or grammatical errors, these errors are not significant in nature and do not affect the understanding of the material presented in the discussion. The document includes figures and tables where appropriate, these are presented in a clear manner, include appropriate captions and are supported by some discussion in the main text of the document.

Project Structure including analysis of data and their evaluation. The student has demonstrated that they are able to explain the issues related to the project undertaken. Although the explanation of some of these issues is limited, the discussion presented indicates that the project undertaken has accounted for these issues.

Higher Range.

Report Structure. The document is written in a clear and concise manner and includes all of the elements that would be expected in this report. All of the section headings appropriately describe the information provided within the text. The text is written as a clearly structured narrative and is organised in a logical manner. The report provides a clear description of the project and its outcomes within the set page limit.

Effectiveness of Presentation.The document contains no spelling or grammatical errors and the reader is able to clearly understand the material presented in the discussion. The document includes figures and tables where appropriate, these are presented in a clear manner, include appropriate captions that clearly describe the figure or table and are supported by a high level of discussion in the main text of the document.

Project Structure including analysis of data and their evaluation. The student has demonstrated that they have identified and analysed the issues related to the design, planning, data collection and analysis. Although the analysis of some of these issues is limited, the discussion presented indicates that the project structure has accounted for these issues.

Figure 1. Map of the studied area, and a line for the cross-section A-A’.

Bore logs

Borehole BH-1.

Depth, m

Rock Type

Degree of

weathering

Characteristics of joints

Rock mass properties

RQD

%

Joint spacing

Joint characteristics

Ground water

Density

g/cm³

Data from lab tests

0.2

Soil with inclusions of small rock pieces

3

14.6

Shale

30

4

joint surfaces are slickensided, undulating, and highly weathered; joint are separated by about 3-5 mm, filled with clay

3

2.3-2.5

Samples were collected at a depth of 7 m and a series of triaxial tests were performed (Table 1).

22.5

Mudstone

72

3

joint surfaces are generally stepped and rough, tightly closed and unweathered with occasional stains

2

2.7-2.9

Samples were collected at a depth of 7 m. JRC of joints about 14-16, Schmidt hammer tests on the rock joint surfaces resulted in an average value of Schmidt hammer rebound number of 37, the peak friction angle was 65°, and the residual friction angle was 30°.

40.0

End of borehole

Granite

84

2

joint surfaces are slightly rough, slightly weathered with stains; no clay found on surface, apertures generally less than 1 mm,

2

3.1-3.3

Samples were collected at a depth of 30 m and shear box tests were carried out (Table 2).

Point load strength index was 5.5 MPa.

I

II

III

IV

V

VI

1: > 3m

2: 1~3m

3: 0.3~1m

4: 5~30cm

5: < 5cm

1:completely dry

2: dry

3: moist only

I : Fresh ~ VI completely weathered

Borehole BH-2.

Depth, m

Rock Type

Degree of

weathering

Rock mass properties

RQD

%

Density

g/cm³

Joint spacing

Ground water

0.1

Soil with inclusions of small rock pieces

3

13.9

Shale

35

2.2-2.4

4

3

22.7

Mudstone

70

2.6-2.8

3

2

40.0

End of borehole

Granite

84

3.1-3.3

2

I

II

III

IV

V

VI

1: > 3m

2: 1~3m

3: 0.3~1m

4: 5~30cm

5: < 5cm

1:completely dry

2: dry

3: moist only

I : Fresh ~ VI completely weathered

Borehole BH-3.

Depth, m

Rock Type

Degree of

weathering

Rock mass properties

RQD

%

Density

g/cm³

Joint spacing

Ground water

16.3

Shale

33

2.2-2.4

4

2

22.9

Mudstone

72

2.6-2.8

3

40.0

End of borehole

Granite

86

3.1-3.3

2

I

II

III

IV

V

VI

1: > 3m

2: 1~3m

3: 0.3~1m

4: 5~30cm

5: < 5cm

1:completely dry

2: dry

3: moist only

I : Fresh ~ VI completely weathered

Borehole BH-4.

Depth, m

Rock Type

Degree of

weathering

Rock mass properties

RQD

%

Density

g/cm³

Joint spacing

Ground water

16.9

Shale

32

2.2-2.4

4

2

24.2

Mudstone

70

2.6-2.8

3

40.0

End of borehole

Granite

86

3.1-3.3

2

I

II

III

IV

V

VI

1: > 3m

2: 1~3m

3: 0.3~1m

4: 5~30cm

5: < 5cm

1:completely dry

2: dry

3: moist only

I : Fresh ~ VI completely weathered

Table 1. Results of triaxial tests on samples of shale.

s_3f, MPa	0	2	5	7
s_1f, MPa	17.2	32.1	45.3	56.0

Table 2. Results of shear box tests on samples of granite.

s, MPa	0	2	5	7
t, MPa	7.2	12.5	15.8	19.2

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score 3 · Accepted Answer · 09/17/2015 01:57 PM

Solution: The Bang Lang dam is one of the major hydro dams in Thailand

Tutorial # 00098610 Posted By: echo7 Posted on: 09/17/2015 01:57 PM

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The Bang Lang dam is one of the major hydro dams in Thailand

Solution: The Bang Lang dam is one of the major hydro dams in Thailand

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