# Triaxial Test

Topics: Sample, Continuum mechanics / Pages: 6 (1391 words) / Published: Jun 3rd, 2013
TRIAXIAL TEST
(UNCONSOLIDATION UNDRAINED)

INTRODUCTION

The purpose of the test is to determine the undrained shear strength and cohesion of cohesive soil.

PROCEDURE

a. Three set of soil specimens with a dimension of 78 mm height and 38 mm diameter are prepared. The specimens are weighed. b. The specimen is placed on the lower end cap and the top cap on the upper end of the specimen. The entire specimen is covered with rubber membrane and rubber O-rings is fitted on top and bottom of the specimen. Make sure that no air is trapped. c. The specimen is placed on the triaxial cell base with the lower end cap correctly seated or screwed into the cell base. Check that the specimen is aligned vertically. The cell body is lowered into the position over the specimen, taking care not to knock the specimen either with the cell walls or with the end of the piston. The base pedestal is wind up by machine until the specimen just makes contact with the load ring. Water is filled in and the required pressure (50, 100, 150kPa) is applied. d. The strain dial gauge on the pillar is adjusted to read zero or a convenient initial reading. The initial reading of the load and strain dial gauges are adjusted, and then the compression test is started. Normally, the rate of strain applied is 2% per minute until the strain of 20% is reached. The test is repeated on the other two specimens but with different applied pressure so that at least 3 Mohr circles can be plotted.

RESULTS AND CALCULATION

SAMPLE 1

Deformation | Compression | Force gauge | Load (N) | Strain | Area (mm²) | Stress (kPa) | gauge reading | (mm) | reading (mm) | | | | | 0.0 | 0.00 | 0.00 | 0.00 | 0.000 | 1064.1957 | 0.0000 | 7.6 | 0.08 | 10.00 | 6.38 | 0.001 | 1065.2610 | 5.9891 | 15.2 | 0.15 | 18.00 | 11.48 | 0.002 | 1066.3284 | 10.7697 | 22.8 | 0.23 | 21.00 | 13.40 | 0.003 | 1067.3979 | 12.5520 | 30.4 | 0.30 | 23.00 | 14.67 | 0.004 | 1068.4696 | 13.7337 | 38.0 | 0.38