Loading in 2 Seconds...

CONSOLIDATION ANALYSIS -stuff you should know to complete your lab assignment

Loading in 2 Seconds...

- By
**Jimmy** - Follow User

- 178 Views
- Uploaded on

Download Presentation
## PowerPoint Slideshow about 'consolidation analysis -stuff you should know to complete your lab assignment' - Jimmy

**An Image/Link below is provided (as is) to download presentation**

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

### CONSOLIDATION ANALYSIS-stuff you should know to complete your lab assignment

CIE 366: Soil Mechanics Laboratory

Originally by Mike St. Pierre, 2007

Modified by Will Manion, 2008

Coefficient of Consolidation (cv)

- For every load increment
- 10 increments -- 10 plots
- Holtz and Kovacs(1981) section 9.4, pg 395
- Use the Casagrande logarithm of time curve fitting method.
- Fig. 9.7 on page 398 shows it nicely.

Coefficient of Consolidation (cv)

- cv (cm2/sec)
- T50 = time factor at U = 50%
- Hdr50 = height of drainage at

U = 50%

- t50 = time at U = 50%
- U = percent of primary consolidation
- From Table 9-1 pg 390
- If Uavg = 50%, T50 = 0.197

Coefficient of Consolidation (cv)Casagrande log time method

- Construct a plot of dial reading vs. log of time
- Figure 9.7, pg 398
- 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

Coefficient of Consolidation (cv)Casagrande log time method: R50

- May have to plot data points and complete construction on paper – see next slide
- 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

R100

Void Ratio (e) versus Log Stress (σ)

- Determine initial height and final height for load increment
- Calculate the void ratio for each load increment
- Plot e versus log effective stress
- You will have to print the plot and perform the construction on papershow all work
- Holtz and Kovacs (1981) Figure 8.6, pg 296

On paper, determine values from theVoid Ratio (e) versus Log Stress (σ) plot

- Using methodology from Figure 8.6
- Determine the (most probable) preconsolidation pressure (σ’p)
- Steps from Holtz and Kovacs pg 296
- Choose point of maximum curvature (point A)
- Draw horizontal line from point A
- Draw tangent to curve at point A
- Bisect angle made in Steps 2 and 3
- Extend straight line portion of virgin compression curve through bisector line

On paper, determine values from theVoid Ratio (e) versus Log Stress (σ) plot

- Determine compression index (Cc)
- Slope of virgin compression curve aka the steep part of curve
- Holtz and Kovacs Figure 8.9 pg 316 graphically
- Holtz and Kovacs Figure 8.7 pg 313 analytically
- Determine recompression index (Cr)
- Slope of the unloading/reloading part of curve
- Holtz and Kovacs Figure 8.9 pg 316

Details, Details, Details

- Consolidation Memo
- Due three weeks from today
- ONE PAPER COPY for the whole group
- Hand draw constructions (Make them neat)
- 11 plot attachments (label them appropriately)
- Each lab member responsible for ONE loading increment and cv plot
- Sign bottom right hand corner

Download Presentation

Connecting to Server..