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Wuttichai Prachantrikal Master Candidate Geotechnical Engineering Civil and Environmental Engineering University of Missouri - Columbia Hydraulic Conductivity.

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Presentation on theme: "Wuttichai Prachantrikal Master Candidate Geotechnical Engineering Civil and Environmental Engineering University of Missouri - Columbia Hydraulic Conductivity."— Presentation transcript:

1 Wuttichai Prachantrikal Master Candidate Geotechnical Engineering Civil and Environmental Engineering University of Missouri - Columbia Hydraulic Conductivity of MoDOT Type 5 Base Rock Geotechnical Engineering

2 Background Objective Scope of Work Methodology Results to Date Ongoing Activities Geotechnical Engineering

3 Type 5 Base Rock is a material containing a wide particle size distribution of gravel, sand, and fines. Used for the base of roadways. Geotechnical Engineering

4 Type 5 Base on Roadway ~4 inches Geotechnical Engineering Hydraulic conductivity of the base for good drainage practice should be about 1 cm/s

5 “The conventional undrained pavements which fail prematurely from water damage are extremely uneconomical in the long-run when compared with well drained pavement” Life undrain pavement ~ yrs Life well drain pavement ~ yrs (H.R.Cedergren, 1967) Geotechnical Engineering

6 Rigid Surface Base Subbase Infiltration No drainage

7 Geotechnical Engineering

8 Objective: Determine the hydraulic conductivity of MoDOT Type 5 base rock and the impact of fines content on the hydraulic conductivity Geotechnical Engineering

9 Scope of work: 1.For a single Type 5 source: a. grain size distribution b. compaction curve c. hydraulic conductivity ( of the compaction curve) 2. Effects of fines content: a. compaction curve b. hydraulic conductivity c. long term flow Geotechnical Engineering

10 Methodology: 1.Sieving 2.Compaction 3.Permeability Testing Geotechnical Engineering

11 Sieving: Geotechnical Engineering

12 Type 5 Grain Size Distribution MoDOT Spec. Percent Fine Range from 0 to 15 percent Sieving: Geotechnical Engineering

13 Aggregate Used in Test Boone Quarries, Columbia, Missouri Fines (Passing #200) – Sieved out Re-Blend the Aggregate to Percent 0, 3, 6, 9, 12, 15% Geotechnical Engineering

14 Compaction ASTM D698 Standard Proctor 6” Diameter 4.5” Height Mold 56 Blows per lift – 3 lifts Geotechnical Engineering

15 Compaction Geotechnical Engineering  max w opt

16 Permeability Testing Rigid-wall, Double-Ring: Geotechnical Engineering

17 Constraints: 1.4” diameter mold 2.Side wall leakage 3.1/8” diameter port 4.S r < 1 Rigid-wall, Double-Ring:

18 6-inch constant head test: Geotechnical Engineering 6” mold

19 6-inch constant head test: Advantages: 1.6” diameter 2.Saturated S r =1 3.Large Flow Capacity 6” mold Geotechnical Engineering

20 inflow overflow Type5 outflow 25.25” 4” 5” 4-inch long-term flow test: GT Geotechnical Engineering

21 Result to Date: 1. Grain Size Dist. Boone County Quarries Geotechnical Engineering Unmodified

22 Grain Size Dist. Boone County Quarries Geotechnical Engineering 0% Fine

23 2. Compaction Curve Geotechnical Engineering

24 Compaction Curve (cont’) Geotechnical Engineering

25 3. Hydraulic Conductivity – 4.5% Fine Rigid Wall Double Ring Geotechnical Engineering

26 k w/ soil (max) = 2 x10 -4 cm/s k inner ring = 1.1x10 -2 cm/s (k system ) k outer ring = 9.3x10 -3 cm/s (k system ) k system > k w/soil OK Geotechnical Engineering Rigid Wall Double Ring (Calibration)

27 Hydraulic Conductivity – 3%Fine Geotechnical Engineering

28 Hydraulic Conductivity of Type 5 Base Geotechnical Engineering

29 Hazen (1911) k(cm/s) = D 10 2 Moulton (1979) k(ft/d) = [ 6.214x10 5 D n ]/P D 10 = particle size in mm at 10% passing n = porosity P 200 = percent passing No.200 Geotechnical Engineering

30 Predicted k vs. Measured k Geotechnical Engineering

31 Summary of Results Geotechnical Engineering

32 Long term flow Geotechnical Engineering

33 Observation to Date Geotechnical Engineering Percent fines in unmodified Type 5 base ~ 4-5% 4 in Rigid Wall Double Ring give much lower k than 6 in permeameter Max Dry Unit weight increase with fine content k decrease with fines content k measure is close to k hazen at both 0, 3% but higher at 6% fines k measure is close to k moulton at 6% but lower at 3% fines Flow rate decrease with time in Long term flow and get to the steady state at about 50 hrs

34 Geotechnical Engineering On Going Activities Continue on 6,9,12,15 Percent Fine Long term flow (Awilda) Field k

35 Question?

36 Grain Size Dist. Boone County Quarries Geotechnical Engineering 3% Fine

37 Grain Size Dist. Boone County Quarries Geotechnical Engineering 6% Fine

38 Geotechnical Engineering Compaction Curve (cont’)

39 Geotechnical Engineering

40 Hydraulic Conductivity - 0% Fine Geotechnical Engineering

41 Hydraulic Conductivity – 6%Fine Geotechnical Engineering


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