Index Properties and Strength Index Properties and Strength of Artificial Soil Using the of Artificial Soil Using the Harvard Miniature Method Harvard Miniature Method Krystal Wilbourn, REU Student Krystal Wilbourn, REU Student Kalaiarasi Vembu, Graduate Mentor Kalaiarasi Vembu, Graduate Mentor & & Dr. C., Vipulanandan, Faculty Mentor Dr. C., Vipulanandan, Faculty Mentor
Objective Objective The overall objective of this research project was to investigate the relationships between the index properties and strength of artificial soil prepared using the Harvard Miniature Method.
Introduction Introduction Compaction characteristics of soil are usually determined by conducting Standard Procter tests in the laboratory over the soil and the test results are utilized in the field for different construction and also for ensuring the quality of construction. However, the test is quite costly and time consuming If the estimation of the moisture-density relationship could be developed on the basis of some tests which are quick to perform, less time consuming and cheap, then the process will help the constructors enormously
Intro Cont’d Intro Cont’d In the present study, moisture-density relationship from Harvard Miniature compaction method with the help of index properties and compressive strength of the soil was studied.
tests performed included the unconfined The tests performed included the unconfined The compression test using the Harvard Miniature compression test using the Harvard Miniature apparatus, liquid limit, and plastic limit tests apparatus, liquid limit, and plastic limit tests Harvard Miniature Apparatus Liquid Limit Test Device Plastic Limit Sample
Materials & Methods Materials & Methods • A compilation of artificial soil mixtures were used in varying proportions in order to better observe characteristics • Mixtures consisted of poorly graded sand with a specific gravity of 2.65, kaolinite with specific gravity of 2.623 and bentonite with specific gravity of 2.89
Sieve Analysis Sieve Analysis Sieve Analysis 100 90 80 70 Percent Finer, % 60 50 40 30 Sand Bentonite 20 Kaolinite 10 0 0.0001 0.001 0.01 0.1 1 Particle Diameter, mm Grain size distribution of sand, kaolinite and bentonite
Compaction Test Compaction Test • Compaction is a process by which the soil particles are artificially rearranged and packed together into a closer state of contact by mechanical means in order to decrease the porosity of the soil and increase its dry density
Harvard Miniature Compaction Harvard Miniature Compaction Harvard Miniature compaction apparatus. (A=tamper, B=mold with collar attached to the base, C=device to remove mold collar without tearing last layer, D=sample extruder, E- compacted samples.
Index Properties Index Properties USCS Artificial Liquid Plastic Plasticity Classific Mixture Limit (%) Limit (%) Index (%) ation 30K70S 15.77 0 15.77 CL-ML 50K50S 23.91 15 8.21 CL-ML 70K30S 31.709 22 15.92 CL B10K40S50 68.25 12 56.25 CH B15K35S50 80.816 10 70.85 CH B20K30S50 106.7 14 93.1 CH 30B70S 142.19 18 124.08 CH 50B50S 213.006 27 185.81 CH 70B30S 342.45 36 306.4 CH
Plasticity Index vs. Liquid Limit Plasticity Index vs. Liquid Limit 100B PI vs LL 100K 450 30B 70S 400 50B 50S Plasticity Index (%) 350 70B 30S 300 250 30K 70S 200 50K 50S 150 70K 30S 100 50 10B 40K 50S 0 15B 35K 50S 0 100 200 300 400 500 600 700 20B 30K 50S Liquid Limit (%) U Line
Max Dry Density vs. Opt Moisture Max Dry Density vs. Opt Moisture Content Content 360 340 Max. Dry density (pcf) 320 300 280 260 240 B, K & S 220 B & S 200 K & S 10 12 14 16 18 20 22 24 Optimum Moisture Content (%)
Max Dry Density vs. Liquid Limit Max Dry Density vs. Liquid Limit Opt MC vs LL 30B 70S 100 Dry Opt Moisture Content 50B 50S 80 30S 70B 60 (psi) 70S 30K 40 30S 70K 20 15B 35K 50S 0 20B 30K 50S 0 100 200 300 400 50K 50S Liquid Limit (%) 10B 40K 50S
Max Dry Density vs. Plasticity Index Max Dry Density vs. Plasticity Index 400 y = -0.1139x + 312.63 R 2 = 0.212 350 300 Max. Dry density 250 200 150 100 50 0 0 50 100 150 200 250 300 350 Plasticity Index
Optimum Moisture Content vs. Optimum Moisture Content vs. Liquid Limit Liquid Limit y = 0.0155x + 15.327 25 R 2 = 0.219 Optimum Moisture Content (%) 20 15 10 5 0 0 50 100 150 200 250 300 350 400 Liquid Limit (%)
Compressive Strength vs. Moisture Compressive Strength vs. Moisture Content (K, S) Content (K, S) 90 80 70 60 30K 70S Qu (psi) 50 50K 50S 40 70K 30S 30 20 10 0 0 5 10 15 20 25 30 Moisture Content %
Optimum Moisture Content vs. Optimum Moisture Content vs. Plasticity Index Plasticity Index Opt MC vs PI 30B 70S 100 50B 50S 80 70B30S Opt MC 60 30K70S 40 50K 50S 20 70K30S 0 10B 40K 50S 0.00 100.00 200.00 300.00 400.00 15B 35K 50S Plasticity Index 20B 30K 50S
Compressive Strength vs. Moisture Compressive Strength vs. Moisture Content (B, K, S) Content (B, K, S) 60 50 40 B10 K40 S50 Qu 30 B15 K35 S50 B20 K30 S50 20 10 0 0 5 10 15 20 25 Moisture Content %
Compressive Strength vs. Moisture Compressive Strength vs. Moisture Content (B, S) Content (B, S) 60 50 40 Qu (psi) 30B 70S 30 50B 50S 70B 30S 20 10 0 10 15 20 25 30 Moisture Content %
Dry Unit Weight vs. Moisture Dry Unit Weight vs. Moisture Content (B,S) Content (B,S) Bentonite and Sand 340 320 Dry Unit Weight (pcf) 300 280 260 30B 70S 50B 50S 240 70B 30S 220 200 10 15 20 25 30 Moisture Content %
Dry Unit Weight vs. Moisture Dry Unit Weight vs. Moisture Content (K, S) Content (K, S) Kaolinite and Sand 450 400 Dry Unit Weight (pcf) 350 300 30K 70S 50K 50S 250 70K 30S 200 0 5 10 15 20 25 30 Moisture Content (%)
Dry Unit Weight vs. Moisture Dry Unit Weight vs. Moisture Content (B, K, S) Content (B, K, S) Bentonite, Kaolinite and Sand 320 310 Dry Unit Weight (pcf) 300 B10 K40 S50 290 B15 K35 S50 B20 K40 S50 280 270 260 8 13 18 23 Moisture Content %
Conclusion Conclusion • The liquid limit and plasticity index of artificial soil increases with increase in clay content and the increase is more pronounced in bentonite/sand and bentonite/kaolinite/sand mixtures • Max dry density decreases and OMC increases with increase in bentonite/kaolinite/sand mixtures • OMC increases with increase in bentonite and decreases with the increase in kaolinite in bentonite , kaolinite and sand mixtures for the same sand content
Conclusion Cont’d Conclusion Cont’d • Peak shear strength increases with increase in clay content except for 50K 50S miture which shows high strength • In the bentonite, kaolinite and sand mix B10K40S50 shows high strength • Relationship between strength and index properties has been brought out based on the test
Recommend
More recommend
