What is OCR of a soil?
The overconsolidation ratio (OCR) is a qualitative indicator of this densification or stiffening of the soil, and it is defined as the ratio of the maximum overburden stress ever experienced by the soil (i.e., with the ice sheet on top) to the present overburden stress (i.e., without the ice sheet).
How do you calculate soil OCR?
Can Overconsolidation ratio be less than 1?
How do you determine if a soil is normally consolidated or Overconsolidated?
Does OCR increase with depth?
How do you do a direct shear test?
- placing a soil specimen in the direct shear device (shear box apparatus)
- applying a predetermined normal stress,
- providing the necessary conditions for wetting and/or draining of the specimen,
- consolidating the specimen under the normal stress,
- placing a soil specimen in the direct shear device (shear box apparatus)
- applying a predetermined normal stress,
- providing the necessary conditions for wetting and/or draining of the specimen,
- consolidating the specimen under the normal stress,
What is an Overconsolidated clay?
over-consolidated clay Clay that has been more compacted than would be expected from the existing overburden, e.g. it has been subjected to pressure from overburden that has subsequently been removed by erosion. Compare NORMALLY CONSOLIDATED CLAY. A Dictionary of Earth Sciences.
How do you measure soil OCR?
OCR is evaluated by the formula: OCR = σ’p / σ’yy. If OCR≤1, the soil is considered to be normally consolidated, when OCR> 1 – it is overconsolidated.
What is soil OCR?
The overconsolidation ratio (OCR) is a qualitative indicator of this densification or stiffening of the soil, and it is defined as the ratio of the maximum overburden stress ever experienced by the soil (i.e., with the ice sheet on top) to the present overburden stress (i.e., without the ice sheet).
What is undrained shear strength?
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.
What is Overconsolidation?
The overconsolidation ratio (OCR) is a qualitative indicator of this densification or stiffening of the soil, and it is defined as the ratio of the maximum overburden stress ever experienced by the soil (i.e., with the ice sheet on top) to the present overburden stress (i.e., without the ice sheet).
What does Overconsolidation mean?
noun. Consolidation to an excessive degree; specifically the consolidation of soil to a greater degree than could have been produced by the present pressure of overburden.
How is soil cohesion measured?
You can do it easily if you have the field standard penetration number (N-value). For example, if you have the N value, you can calculate cohesion, Cu=KN, where K=constant=3.5-6.5 kN/sq. m and N= field N-value.
How do you measure soil strength?
The laboratory vane shear test is used for the measurement of undrained shear strength of cohesive soils of low shear strength less than about 0.5 kgf/cm2. This test gives the undrained strength of the soil, and the undisturbed and remolded strengths obtained are also used for evaluating the sensitivity of the soil.
What is OCR of a soil?
The overconsolidation ratio (OCR) is a qualitative indicator of this densification or stiffening of the soil, and it is defined as the ratio of the maximum overburden stress ever experienced by the soil (i.e., with the ice sheet on top) to the present overburden stress (i.e., without the ice sheet).
What is a consolidation test?
Consolidation test is used to determine the rate and magnitude of soil consolidation when the soil is restrained laterally and loaded axially. The Consolidation test is also referred to as Standard Oedometer test or One-dimensional compression test.
How many types of consolidation are there?
Full consolidation, proportionate consolidation, and equity consolidation are the three consolidation methods.
What is OC clay?
over-consolidated clay Clay that has been more compacted than would be expected from the existing overburden, e.g. it has been subjected to pressure from overburden that has subsequently been removed by erosion. Compare NORMALLY CONSOLIDATED CLAY. A Dictionary of Earth Sciences.
What is NC clay?
Clay that is compacted by exactly the amount to be expected from the pressure exerted by the overburden; clay which has never been overloaded. Compare over-consolidated clay. From: normally consolidated clay in A Dictionary of Earth Sciences »
What is a shear box test?
Shear box test is a testing method used to determine the shear strength of a soil sample. Since granular soils cannot be retrieved undisturbed, the soil is re-compacted inside a shear box. The soil’s friction angle is then determined by direct shear and the tests are carried out under saturated conditions.
How is a direct shear test done?
Testing Equipment and Procedure
The soil specimen is placed in an apparatus known as shear box which consists of two metallic plates, two porous stones, two screws, a gripper disk and a loading cap where the normal stress is applied.