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Geotechnical Engineering–I [CE-221]
BSc Civil Engineering – 4th Semester
by
Dr. Muhammad Irfan
Assistant Professor
Civil Engg. Dept. – UET Lahore
Email: mirfan1@msn.com
Lecture Handouts: https://groups.google.com/d/forum/2016session-geotech-i
Lecture # 16
16-Mar-2018](https://image.slidesharecdn.com/16-180923184544/85/Geotechnical-Engineering-I-Lec-16-Soil-Compaction-Practice-Problems-1-320.jpg)
Geotechnical Engineering-I [Lec #16: Soil Compaction - Practice Problems]
- 1. 1 Geotechnical Engineering–I [CE-221] BSc Civil Engineering – 4th Semester by Dr. Muhammad Irfan Assistant Professor Civil Engg. Dept. – UET Lahore Email: [email protected] Lecture Handouts: https://groups.google.com/d/forum/2016session-geotech-i Lecture # 16 16-Mar-2018
- 2. 2 You are a Project Engineer on a large dam project that has a volume of 5×106 yd3 of select fill, compacted such that the final void ratio in the dam is 0.80. Your boss, the Project Manager delegates to you the important decision of buying the earth fill from one of three suppliers. Supplier A sells fill at Rs. 50/yd3 with e = 0.90 Supplier B sells fill at Rs. 33/yd3 with e = 2.00 Supplier C sells fill at Rs. 44/yd3 with e = 1.60 Which one of the three suppliers is the most economical, and how much will you save? Practice Problem #8
- 3. 3 Based on the previous problem data, if the fill dumped into the truck has an e = 1.2, how many truck loads will you need to fill the dam? Assume each truck carries 10 yd3 of soil. Practice Problem #9
- 4. 4 Practice Problem #10 A proposed earth embankment is required to be compacted to 95% of Standard Proctor dry density. Tests on the material to be used for the embankment gives maximum dry density of 1.98 Mg/m3 at optimum content of 12%. The borrow pit material in its natural condition has a void ratio of 0.6. If Gs for borrow pit material is 2.7, what is the minimum volume of borrow material required to make 100 cu. m of acceptable compacted fill.
- 5. 5 Practice Problem #11 A sand deposit was compacted dry to an in-place void ratio of 0.45. For this sand emax = 0.7 and emin = 0.3. Determine the relative density and relative compaction of this deposit. Gs = 2.65.
- 6. 6 Practice Problem #12 a. Why does a vibratory roller compact the granular soils more effectively? Explain. b. Laboratory compaction test results of a soil fill compacted at site are: Specifications call for the compacted density to be at least 95% of the maximum laboratory density and w within + 2% of OMC. In a sand replacement test, the volume of the soil excavated was 1160 cm3. It weighed 2210 grams wet and 1880 grams dry. i. What is the compacted dry density in the field? ii. What is the field moisture content? iii. What is the degree of compaction? iv. Does the test meet the specifications? v. What is the degree of saturation of the field sample? vi. If the sample was saturated at constant density, what would be the moisture content? 𝛾d (Mg/m3) 1.62 1.66 1.72 1.70 1.63 1.57 w % 12.4 13.3 15.5 17.4 18.3 20.1
- 7. 7 Practice Problem #13 During subsoil investigations in a sand deposit, it was found that SPT blow count is very low. Subsequent tests on the sand revealed that it had an average in-situ void ratio of 0.70. The maximum and minimum void ratios were found to be 0.75 and 0.35 respectively. It was decided to densify the sand deposit by subsurface explorations. After the densification was carried out, the average void ratio of the deposit was found to be 0.55. Calculate the change in in-situ relative density of the sand deposit. Would the SPT blow count increases or decreases after densification?
- 8. 8 CONCLUDED REFERENCE MATERIAL An Introduction to Geotechnical Engineering (2nd Edition) By R. D. Holtz, W. D. Kovacs and T. C. Sheahan Chapter #5 Principles of Geotechnical Engineering – (7th Edition) Braja M. Das Chapter #6