Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Determination of Co-efficient The similarity between the laboratory curve and theoretical curve is used for the determina...
Methods Generally used methods are:  Square root of time fitting method  Logarithm of time fitting method
Square root of time fitting method This method, developed by Taylor, utilizes theoretical  relationship between U and √Tv...
Time Consolidation Curve
Co-efficient of Consolidation (Cv) From curve,   cv (cm2/sec)                T90 = time factor                when U is 9...
Logarithm of time fitting method This method, developed by A. Casagrande, determines 100% U on semi log plot of laborator...
Logarithm of time fitting method Construct a plot of dial reading vs. log of time To determine Ho = Initial height of s...
Coefficient of Consolidation (cv)Casagrande log time method: R50   determine Ro, when U = 0%      this is NOT your first...
RoR100
RoR50 = (R100-Ro) / 2R100
Coefficient of Consolidation (cv)                cv (cm2/sec)                T50 = time factor at U =                 50...
Determination of co efficient of consolidation method
Determination of co efficient of consolidation method
Determination of co efficient of consolidation method
Upcoming SlideShare
Loading in …5
×

Determination of co efficient of consolidation method

25,047 views

Published on

Published in: Education

Determination of co efficient of consolidation method

  1. 1. Determination of Co-efficient The similarity between the laboratory curve and theoretical curve is used for the determination of the co-efficient of consolidation (Cv) of soil.
  2. 2. Methods Generally used methods are:  Square root of time fitting method  Logarithm of time fitting method
  3. 3. Square root of time fitting method This method, developed by Taylor, utilizes theoretical relationship between U and √Tv. The relationship is linear up to value of u equal to about 60%. It was observed that at U=90%, value of √Tv is 1.15 times value obtained by extension of the initial straight line portion. A curve is plotted from consolidation test results between dial gauge reading (R) as ordinate and √T.
  4. 4. Time Consolidation Curve
  5. 5. Co-efficient of Consolidation (Cv) From curve, cv (cm2/sec) T90 = time factor when U is 90% d = drainage path t50 = time when U is 50% U = percent of primary consolidation
  6. 6. Logarithm of time fitting method This method, developed by A. Casagrande, determines 100% U on semi log plot of laboratory time consolidation curve by theoretical curve between U and log Tv.
  7. 7. Logarithm of time fitting method Construct a plot of dial reading vs. log of time To determine Ho = Initial height of specimen Rstart = 0 (if you zeroed the dial at the beginning of the test) R50 you determine from the plot
  8. 8. Coefficient of Consolidation (cv)Casagrande log time method: R50  determine Ro, when U = 0%  this is NOT your first reading  determine R100, when U = 100%  then average to find R50,  which then graphically corresponds to t50
  9. 9. RoR100
  10. 10. RoR50 = (R100-Ro) / 2R100
  11. 11. Coefficient of Consolidation (cv)  cv (cm2/sec)  T50 = time factor at U = 50%  d = drainage path  t50 = time at U = 50%  U = percent of primary consolidation  If Uavg = 50%, T50 = 0.197

×