TTA30-1 Bench-type Triaxial Testing Apparatus

Used to determine the shear resistance of soil to measure the stability of soil structure.

Total stresses are normally measured in a triaxial cell where the sample is subject to an all round confining pressure. A load is applied through a piston onto a pressure pad, with the sample being confined within a rubber membrance so that no drainage in or out of the specimen is allowed.

Pore water pressuers are not normally measured and the undrained test is often referred to as the QU-TXL test.

An etension of the QU test is the uncolidated undrained test(UU); this is similiar to the QU test but is run at a slower rate in order to measure pore water pressure

Effective stress tests are usually referred to as consolidated drain(CD) or consolidated undrained (CU). Generally the CD test is applicable to sands, while both many special test variations within these basic test groupings.