Question

Describe how a consolidated – drained triaxial test is conducted. Feel free to use a sketch to aid your explanation. What quantifies are measured during testing?

Answer 1

In consolidated drained test ,drainage is allowed in both the stages.loading rate is slow to allow water to expel out every where.hence pore water pressure does not build up and we gets effective stress parameters.

It gives two type of curve one for normally consolidated and other for over consolidated.For normal consolidated soil ,the failure envolep passes though the origin and for over consolidated ,it will not have 0 shear strength at zero confining stress.ie it does not passes though the origin

Progressively bigger Mohr circle are formed because initial void ratio will progressively decrease as more and more higher confining pressure is applied ,hence progressively higher deviator stress is required for failure of soil.

Use of CD test

1). Analysis of gradual loading condition

2) to check long term stability of embankment