What is the undrained shear strength of clay?

What is the undrained shear strength of clay?

The undrained shear strength (su) is defined as one-half of the peak value of (P1 – P3). For CU tests, the slower strain rates of Raymond should be retained to more closely approximate field rates of loading. The UU test provides a measure of Su at the in situ water content of the sample.

Is clay drained or undrained?

Clay behavior depends on the rate of loading (or unloading). When “fast” stress changes take place then clay behavior is typically modeled as “Undrained” while slow stress changes or long term conditions are typically modeled as “Drained”. In the software, the default behavior of a clay type soil is set as “Undrained”.

What is the difference between drained and undrained test of soil shear strength?

Drained Shear Strength: The soil is free to dilate or contract during shear if the soil sample is totally drained. Undrained Shear Strength: Whenever water is not allowed to flow in or flow out of the soil then the stress path is called as undrained stress path.

What is CU for clay?

undrained shear strength
The undrained shear strength (cu) is considered one of the most basic para- meter characterizing soils in engineering practice. The particular importance of cu is in the case of clayey soil. This parameter also is the basis for the classification of soil according to the ISO standard.

Is drained or undrained shear strength higher?

Compared to drained strength ( c ′ , ϕ ′ c’, \phi’ c′,ϕ′), undrained shear strength is often much easier and cheaper to measure. It can be derived from an unconfined compression test (UU triaxial), vane shear test or simply using a pocket penetrometer.

What is undrained analysis?

If the soil is normally consolidated clay, the short-term (undrained) analysis governs due to development of positive pore water pressure. If the soil is overconsolidated clay, the long-term (drained) analysis governs due to development of negative pore water pressure in the short-term.

What is Cu in clay soil?

The undrained shear strength (cu) is considered one of the most basic para- meter characterizing soils in engineering practice. The particular importance of cu is in the case of clayey soil. This parameter also is the basis for the classification of soil according to the ISO standard.

Is Direct Shear Test drained or undrained?

The Direct Shear Test is used for determination of the consolidated drained (or undrained) shear strength of soils. The test is performed by deforming a specimen at a controlled rate on or near a single shear plane.