Effect of cyclic load on the cbr of a clayey soil
- 1. Effect of cyclic load on the CBR of a clayey soil Prepared by : Ali Yassine Hussein Chreim Mohammad Zein Advisor: Dr. Robert Nini Soil Unloading Soil Reloading Soil Loading
- 2. Project content • Part 1 : Introduction • Part 2 : Literature review • Part 3 : Experimental part • Part 4 : Analysis part • Part 5 : Conclusions and Recommendations
- 4. Introduction The traffic load on a highway is not uniform during the time. The clay is the main subgrade of many countries. California Bearing Ratio (CBR) of clay is weak. The CBR decreases with moisture content. For this reason, the cyclic load will be tested in this project
- 5. Introduction The experiments performed in this project : 1. Proctor test 2. CBR test 3. Atterberg limit 4. Hydrometer test 5. Specific gravity 6. Sieve analysis The cyclic load will be done for 0.1 in and 0.2 in penetration. The CBR will be done for 3 cycles of loading. Six soil samples were collected from Lebanon to get various results.
- 7. Literature Review Ali and Mir, (2016) They used the human hair fibers to enhance the CBR of clayey soil. Frangieh et al.(2015) They tried to improve the CBR value of clay by draining the clay by using a layer of sand between the layers of clay in the CBR mold. Vibhakar and Nahta (2014) They used some fibers in the CBR mold to get higher values on the CBR test. Wojcieh and Gluchowski (2013) They tried to discover how the CBR value of clay is affected by using different type of load . Yetimoglu et al (2005) They studied the effect of reinforcing sand fills with fibers overlying the soft clay.
- 9. Experimental Part • Main experiments 1. Proctor Test: optimum moisture content (OMC) 2. California Bearing Ratio (CBR) loading Unloading Reloading Proctor Test
- 10. Experimental part • Identification Tests Sieve Analysis Atterberg Limits Atterbeg Test Sieve Nb.40
- 11. Experimental part • Identification Tests Specific Gravity Hydrometer test Hydrometer Test Sample Preparation
- 13. Experimental Part • Working on different types of soils was a necessity in order to cover different types of Lebanese clayey soils. Six clayey soil were collected from Lebanon.
- 14. Experimental Part • Result of Experiments Soil (Shoukin) - Silt and Clay fraction = 88.5% - PL=32.6% - Clay fraction =62% - LL=57% - PI=33.33% y = -0.0047x2 + 0.1718x + 14.883 R² = 0.9999 16.2 16.25 16.3 16.35 16.4 16.45 16.5 0 5 10 15 20 25 30 DryunitweightKN/m3 Water content % PROCTOR proctor Poly. (proctor) OMC= 18.28% ODD= 16.45 KN/m3 HYDROMETER ATTERBERG
- 15. Experimental Part • Result of Experiments Soil (Jbaa) y = -0.012x2 + 0.4133x + 7.78 R² = 0.9855 10.2 10.5 10.8 11.1 11.4 0 5 10 15 20 25 30 DryunitweighrKN/m3 water content % proctor proctor Poly. (proctor) -Silt and Clay fraction = 57.59% - PL= 30% -Clay fraction =41.44% - LL=63.81% -PI=33.81% Hydrometer Result Atterberg Result OMC= 17.22% ODD= 11.34KN/m3
- 16. Experimental Part • Result of Experiments Soil (Zawtar) y = -0.0081x2 + 0.3434x + 6.5439 R² = 0.9993 9.5 9.6 9.7 9.8 9.9 10 10.1 10.2 10.3 0 5 10 15 20 25 30 DRyunitweightKN/m3 Water content % proctor proctor Poly. (proctor) -Silt and Clay fraction = 76.99% - PL=43.85% -Clay fraction =53.99% - LL=57.94% -PI=14.09% Hydrometer Result Atterberg Result OMC= 21.2 % ODD= 10.18 KN/m3
- 17. Experimental Part • Result of Experiments Soil (Kfaroman) y = -524.57x2 + 96.282x + 15.763 R² = 0.9864 18 18.5 19 19.5 20 20.5 0% 2% 4% 6% 8% 10% 12% 14% DryunitweightKN/m3 water contrent % Proctor Proctor Poly. (Proctor) -Silt and Clay fraction = 47.82% - PL=19.15% -Clay fraction =24.01% - LL=33.8% -PI=14.65% Hydrometer Result Atterberg Result OMC= 9.7% ODD= 20.22 KN/m3
- 18. Experimental Part • Result of Experiments Soil (Houmin) y = -0.0336x2 + 1.3967x + 2.9169 R² = 0.9997 15 15.5 16 16.5 17 17.5 18 10 15 20 25 30 DryunitweightKN/m3 Water content % Proctor Proctor Poly. (Proctor) -Silt and Clay fraction = 50.35% - PL=44.82% -Clay fraction =31.28% - LL=60.76% -PI=15.94% Hydrometer Result Atterberg Result OMC= 20.78% ODD= 17.43 KN/m3
- 19. Experimental Part • Result of Experiments Soil (Kfartbnit) y = -0.0114x2 + 0.514x + 10.451 R² = 0.9924 14.4 14.8 15.2 15.6 16 16.4 0 5 10 15 20 25 30 DryunitweightKN/m3 Water content % proctor proctor Poly. (proctor) -Silt and Clay fraction = 88.53% - PL=33.33% -Clay fraction =62.01% - LL=52.74% -PI=19.41% Hydrometer Result Atterberg Result OMC= 22.54% ODD= 16.25 KN/m3
- 20. Experimental part : CBR • Soil 1 ( Houmin) 0 0.2 0.4 0.6 0.8 1 1.2 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 PressurekPA Penetration(in) Virgin clay 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 0.1 0.2 0.3 0.4 Presaure(kPa) Penetration(in) At 0.1 in cbr loaded cbr reloaded cbr reloaded 2 cbr reloaded 3 CBR Loaded CBR reloaded CBR reloaded 2 CBR reloaded 3 0 0.5 1 1.5 2 2.5 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Pressure(kPa) Penetration(in) At 0.2 in cbr loaded cbr reloaded cbr reloaded 2 cbr loaded 3 CBR loaded CBR reloaded CBR reloaded 2 CBR reloaded 3
- 21. Experimental part : CBR • Soil 2 (Jbaa) 0 0.05 0.1 0.15 0.2 0.25 0.3 0 0.1 0.2 0.3 0.4 Pressure(kPa) Penetration(in) Virgin clay 0 0.05 0.1 0.15 0.2 0.25 0.3 0 0.1 0.2 0.3 0.4 Pressure(kPa) Penetration(in) At 0.1in cbr loaded cbr reloaded CBR loaded CBR reloaded CBR reloaded 2CBR reloaded 3 0 0.05 0.1 0.15 0.2 0.25 0.3 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Pressure(kPa) Penetration(in) At 0.2in cbr loaded cbr reloaded cbr reloaded 2 cbr loaded 3 CBR loaded CBR reloaded CBR reloaded 2 CBR reloaded 3
- 22. Experimental part : CBR • Soil 3 (Kafaroman) 0 0.5 1 1.5 2 2.5 3 3.5 4 0 0.1 0.2 0.3 0.4 Pressure(kPa) Penetration(in) Virgin clay 0 0.5 1 1.5 2 2.5 3 3.5 4 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Pressure(kPa) Penetration(in) At 0.1in cbr loaded cbr reloaded cbr reloaded 2 cbr reloaded 3 CBR loadedCBR reloadedCBR reloaded 2CBR reloaded 3 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Pressure(kPa) Penetration(in) At 0.2in cbr loaded cbr reloaded cbr reloaded 2 cbr reloaded 3 CBR loaded CBR reloaded CBR reloaded 2 CBR reloaded 3
- 23. Experimental part : CBR • Soil 4 (Kfartbnit) 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Pressure(kPa) Penetration(in) Virgin clay 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0 0.1 0.2 0.3 0.4 Pressure(kPa) Penetration(in) At 0.1in cbr loaded cbr reloaded CBR loaded CBR reloaded CBR reloaded 2 CBR reloaded 3 0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Pressure(kPa) Penetration (in) At 0.2in cbr loaded cbr reloaded cbr reloaded 2 cbr loaded 3 CBR loaded CBR reloaded CBR reloaded 2 CBR reloaded 3
- 24. Experimental part : CBR • Soil 5 (Shoukin) 0 0.05 0.1 0.15 0.2 0.25 0.3 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Pressure(kPa) Penetration(in) Virgin clay 0 0.05 0.1 0.15 0.2 0.25 0 0.1 0.2 0.3 0.4 Pressure(kPa) Penetration(in) At 0.1in cbr loaded cbr reloaded cbr reloaded 2 cbr reloaded 3 CBR loaded CBR reloaded CBR reloaded 2 CBR reloaded 3 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0 0.1 0.2 0.3 0.4 Pressure(kPa) Penetration(in) At 0.2in cbr loaded cbr reloaded cbr reloaded 2 cbr loaded 3 CBR loaded CBR reloaded CBR reloaded 2 CBR reloaded 3
- 25. Experimental part : CBR • Soil 6 (Zawtar) 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Pressure(kPa) Penetration(in) Virgin clay 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 0.1 0.2 0.3 0.4 Pressure(kPa) Penetration(in) At 0.1in cbr loaded cbr reloaded CBR loaded CBR reloadedCBR reloaded 2CBR reloaded 3 0 0.2 0.4 0.6 0.8 1 1.2 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 Pressure(kPa) Penetration(in) At 0.2in cbr loaded cbr reloaded cbr reloaded 2 cbr loaded 3 CBR loaded CBR reloaded CBR reloaded 2 CBR reloaded 3
- 27. Analysis Part: Increment Ratio Summary Table CBR virgin CBR First cycle CBR Second cycle CBR Third cycle Soils Location 0.1 in 0.2 in 0.1 in IR 0.2 in IR 0.1 in IR 0.2 in IR 0.1 in IR 0.2 in IR S1 Houmin 0.9 1.08 0.8 0.89 0.99 0.92 0.79 0.87 1.11 1.03 0.83 0.92 1.59 1.48 S2 Kafaroman 2.23 2.93 1.9 0.85 2.88 0.98 2.14 0.96 3.31 1.13 2.57 1.15 3.69 1.26 S3 Kafartbnit 0.29 0.35 0.33 1.15 0.34 0.96 0.29 1 0.41 1.16 0.3 1.04 0.49 1.39 S4 Shoukin 0.15 0.22 0.19 1.25 0.22 1 0.2 1.31 0.24 1.11 0.19 1.25 0.3 1.35 S5 Zawtar 0.33 0.44 0.38 1.15 0.52 1.2 0.4 1.21 0.7 1.6 0.42 1.27 0.82 1.88 S6 Jbaa 0.12 0.22 0.17 1.49 0.22 1.02 0.2 1.7 0.22 1.01 0.22 1.91 0.25 1.13
- 28. Analysis Part: identification tests Summary Table Soil Location Soil 1 Houmin Soil 2 kafaroman Soil 3 Kfartbnit Soil 4 shoukin Soil 5 Zawtar Soil 6 Jbaa Plastic Limit % 44.82 19.15 33.33 23.6 43.85 30 Liquid Limit % 60.76 33.80 52.74 56.93 57.94 63.81 Plasticity Index % 15.94 14.65 19.41 33.33 14.09 33.81 Specific Gravity 2.55 2.64 2.73 2.51 2.54 2.62 OMC % 20.78 9.7 22.54 18.28 21.2 17.22 Maximum dry density Kg/m3 1743 2022 1625 1645 1018 1134 Sand Fraction % 14.14 48.3 9.56 11.17 6.94 18.09 Silt and clay fraction % 50.35 47.82 88.53 84.71 76.99 57.59 Clay Fraction % 31.28 24.01 62.01 52.44 53.99 41.44 Silt Fraction % 19.07 23.81 26.52 32.27 23 16.15
- 29. Analysis Part The soil S2 with highest sand and smallest clay fraction has the maximum value of CBR for virgin soil and under cyclic load. The soil S2 with highest CBR has the highest ɣd for proctor test. The increment ratio for CBR in : First cycle of load ranges between 0.85→1.25 Second cycle of load ranges between 0.87→1.698 Third cycle ranges between 0.92→1.9
- 30. Analysis Part The clay fraction alone cannot play any role affecting the CBR increment. The soil S5 that has the lowest sand fraction which is equal to 6.94% presents the highest increment ration at 0.2 in. The soil S6 that has the lowest silt fraction which is equal to 16.15%, shows the highest increment ration at 0.1 in
- 31. Part 5 Conclusion and Recommendation
- 32. Conclusions and Recommendations Conclusions: • The cyclic load affects positively the CBR of a clayey soil. • Under higher penetration 0.2 in ,the increasing of CBR under cyclic load is higher for some soils: S4, S5 and S6 than 0.1 in penetration. (higher is the applied traffic surcharge, better is the CBR under cyclic load). • The cyclic load shows better CBR results than the continuous load.
- 33. Conclusions and Recommendations Recommendations: • The research will be better if more samples are tested. • More cycles are beneficial to be done to see if the results will stay the same. • The results will be more adequate if the conditions of the laboratory are enhanced. • Using the RLT machine is important to get various results.
Editor's Notes
- #2: The cyclic can be defind as its shown in th slide by loading unloading reloading. The traffic load is an important example about this kind of load since cars do not exist all the time on the highway.
- #3: During our presentation we are going to cover all chapters of this project. First,I will start by a small introduction about our project,than I will talk about the literature review wich contains some articles similar to our project’s idea. Than we will wxpose one of the main part of the project wich is the experimental part. After that we will talk about the analysis part where results are compared and analysed to reach the conclusions and recommendations.
- #4: The chapter 1 will be the introduction
- #5: We chows to study the effect of cyclic load on the cbr of a soaked clay for many reasons: First,the traffic load on a highway is not uniform during time,and since the traditional cbr is done by a continuos load of the piston on the soil,so the two cases are not similar. More over,in many countries and especially in Lebanon the subgrade is formed from clay. This kind of soil shows a weak value of cbr and especially when it is soaked.
- #6: The experiments performed on this project are divided in two categories: The main experiments wich are the proctor test and the cbr test . And the identification tests such as atterberg limit,hydrometer test and specific gravity. The cyclic load is performed at 0.1 and 0.2 un penetration because they are the standard values. 6 samples are collected from south Lebanon and they are tested under 3 cycles to get various results.
- #7: Now I will be taking about the literature review
- #8: We found some articles where researches tried to enhance the cbr of clay. The first one ali and mir used te human hair fibers to enhance the cbr of a clayey soil. And the date of publication shows that it is a recent research. Faranjieh…… Vibhakar…. Wojisi….. Yetimoglo…. These researches have some weak points because some of them adding new materials to the soil and others did not used many samples to see the effect of the cyclic load. Because of this we are going to study the cyclic load in details. Now I will give the turn to ali to explain the wxperimental part.
- #10: The main experiment in this project are proctor test and California bearing ratio (CBR). The proctor test is an experiment to get the optimum moisture content and dry unit weight after compaction. The cbr test is performed to discover the relation between the pressure done by the piston and its penetration . The cbr under a cyclic load means that there are 3 phases first one is loading second one is unloading and third one is reloading.
- #11: we also have the identification test , sieve analysis is done to get the % of particules passing nb 200 wich is clay and silt fraction and nb 4 which is sand fraction. And the atterberg limits in order to get the liquid limit pastic limits and plastisty index. This pictures show the preparation of soil to atterberg test by using sieve nb 40
- #12: we also have the specific gravity was nesecity in order to finish the hydrometer calcuations. And the hydromter test give us the silty and clayey fraction and especially the clayey fraction.
- #13: This chart shows the ditails of our works in this 2 semester from collecting different type of soils , then the 2 categories of tests are performed especially CBR test which is done by continuous load and cyclic load t 0.1 in and 0.2 in penetrations , finally the result are collected and analyzed to get the conclusion.
- #14: The 6 soils are from the south of Lebanon , wen brought them from houmin ,kfaromen , choukin, jbaa zawtar and kfartbnit. We worked in different type of soil because is better to cover different types of Lebanese clayey soils. Most of simple were very wet , we had to dry them by using the oven at temperature of 55 c because we need specific moisture content such as 10 15 20 25 to plot the parabola of proctor test .
- #15: This graph shows the dry unit weight on function of water content to get the OMC and max dry unit weight according to the highest point on this parabola. Furthermore , we put its equation and to be very specific we put the error which is R ad since its close to 1 our works is right. The hydrometer results are presented in this slide as clay fraction And the atterberg limits in order to get the liquid …..
- #16: This soil from jbaa has a weak maximum dry unit weigt which is equal to 11.34
- #17: And this soil from zawtar also has a lowest dry unit weight 10.18 with high percentage of clay fraction equal to 53.99
- #18: this soil from kafaromen has a low OMC which is 9.7
- #19: These are the result of soil houmin
- #20: These are the result of soil kfartbnit
- #21: This is the heart of this project which is the CBR test. This 3 graph show 3 different cases of this test. The first one is done as traditional CBR where the vergin clay is tested by continuous load. The second graph show the result of 3 cycle at 0.1 in pene. First we started the test by continuous load of the piston to 0.1 in pene. Then we sweetshed off the machine for 10 min. then we reloaded the soil to 0.1 in pene. We repeated this cycle 3 times. The third graph shows the result of 3 cycle at 0.2 in pene. The work is similar to the previous case but here the continuous load is done to 0.2 in pene. The upper curve is done to 0.3 in pene in the second and third cruve tobe able to compare it to thevergin clay.
- #22: This soil has Disttterbnss at 0.1 in penetration
- #23: This soil have a constant increment at 0.2 in penetration .
- #24: This is the result of kafrtbnit soil
- #25: This is the result of shoukin soil
- #26: This is the result of zawtar soil , it has a higher increment at 0.2 in than 0.1 in penetration
- #34: We need to make this test on more samples to have more results which will give us the chance to a better analysis. We also need to do more cycles to see if the behavior of the soil will keep the same and to see when it will reaches the fatigue faze. The result will be more adequate if we enhanced the conditions of the laboratory such as temperature and humidity because these conditions can damage the results. It will be beneficial to repeat this work by using the repeated load triaxle machine because having results for the same test using two machines is very important and gives more results. Thank you for ur listening and we are ready for ur questions.