THE UNIVERSITY OF THE WEST INDIES

ST AUGUSTINE, TRINIDAD

CIVIL AND ENVIRONMENTAL DEPARTMENT

SOIL LABORATORY

CVNG 2009 LABORATORY REPORT GUIDE

(V1.0)

BY: DAMIAN V. A. ALEXANDER

DR. DEREK GAY

LAB REPORT OUTLINE (FOR EACH LAB)

COVE PAGE Includes

- Name of Experiment

- Name of Student

- ID #

- Group #

- Date experiment was performed

- Date for lab report submission

- Course Code

- Year/Semester

TITLE

TABLE OF CONTENT

AIM

OBJECTIVE(S)

APPARARUS USED (A labelled sketch or Picture of all equipment used)

INTRODUCTION (2-3 short paragraphs including equations)

PROCUDURE Written in Point Form

RESULTS Tabulated results

ANALYSIS (CALCULATIONS)

DISCUSSION

CONCLUSION

REFERENCES Chicago manual of style 16th edition (Author-Date)

APPENDIX (This includes the data sheets or raw data obtained from the lab for each lab)

TRIAXIAL TEST

ANALYSIS OF RESULTS

1) Determine the water content of the sample. (Show all working!)

2) Determine the Unit weight () and Dry Unit weight (d) of the sample (Show all working!)

3) Compute (Show sample calculations/units)

a. Axial Strain 1

b. Area Correction A

c. Deviator Stress -

4) Plot vs. 1 for each data set of results (3 graphs) to determine the maximum stress (f) at failure

for each graph.

5) Determine the major principle stress at failure 1f for samples.

6) Plot Mohr-Coulomb failure envelope and then determine the value of (internal angle of friction)

and cohesion.

DISCUSSION

1) Briefly Discuss :

- Coulombs law of soil shear strength

- Modified Coulombs law

- The Mohr-Coulomb yield theory

2) Comment on the graphs plotted (Stress vs Strain and Mohr Circle plot) and the value of (internal

angle of friction) and compare to typical values found for the tested soil.

3) State 3 Errors that may have occurred during the lab and their associated precautions that should be

taken to minimize or remove such errors.

4) Recommend improvements that may be taken to improve the lab in terms of improving its accuracy

and precision.

REFERENCE TEXT :

Michael E. Kalinski, Soil Mechanics Lab Manual, 2nd Edition, John Wiley & Sons, 2011 (page 179)

1D CONSOLIDATION TEST

As part of a full Consolidation Lab Test you have recorded data in respect of the time dependent

deformation of a soil sample due to a single load step. This represents a single load stage of consolidation.

ANALYSIS OF RESULTS

In your write up this test, you would be required to carry out the following analysis of results:

(1)Plot a graph of deformation vs the square root of time t and determine the time to 90% consolidation,

t90. Using this value of t, determine the coefficient of consolidation cv; where Tv = cv.t/D2

(2)Plot a graph of deformation vs log10 of time and determine the time to 50% consolidation, t50. Using

this value of t, determine the coefficient of consolidation cv; where Tv = cv.t/D2

(3)Determine the total compression during this load stage, h and the value of the coefficient of volume

compressibility mv; where mv = (h/h)/.

(4)Determine the permeability k of the sample during this load stage, where cv is given by equation

(2.15).

(5)Determine the pore water pressure at the center of the soil sample at times t25, t50, t75 and t90. (your

solutions should indicate the number of terms required to achieve a stable solution at each time interval)

(6)Determine the degree of consolidation at the center of the soil sample at times t25, t50, t75 and t90. (your

solutions should indicate the number of terms required to achieve a stable solution at each time interval)

(7)Using equation (2.21) and the 100% primary consolidation 100, plot the theoretical time vs settlement

curve and the measured curve on the same axes, compare and comment on these.

NB: SHOW ALL CALCUTIONS AND THERE UNITS! (SAMPLE CALCULATIONS CAN BE

USED FOR REPEATING CALCULATIONS) ATTACHED A COPY OF EXCEL SPREAD

SHEET USED FOR ALL CALCULATIONS ON A CD

userSticky Notedrainage path length

using lab manual eqns

userSticky Note1.15 from 1d consol notes for gay

userSticky Notetime required for 25% consol

use eqn 1.18 to calc pore pressureM = pi/2(2m+1) where pi is in radsm = 0,1,2,3...

userSticky Noteplot on pg 147

userSticky Noteeqn 1.20 and 1.211.20 gives the percent consol for that depth in the soil1.21 gives the percent consol for the entire depth of the sample

userHighlight

userHighlight

DISCUSSION

1) Discuss commenting on the graphs plotted in terms of the data set used and values of Cv (s) obtained.

2) Identify and state applications of the consolidation test.

3) State 3 Errors that may have occurred during the lab and their associated precautions that should be

taken to minimize or remove such errors.

4) Discuss the limitations of 1D consolidation test.

5) Recommend improvements that may be taken to improve the lab in terms of improving its accuracy

and precision.

REFERENCE TEXT :

Michael E. Kalinski, Soil Mechanics Lab Manual, 2nd Edition, John Wiley & Sons, 2011 (page 121)