Gilson Soil Consolidation Testing
[ Ссылка ]

Karl von Terzaghi, (father of modern soil mechanics) defined soil consolidation as, "Any process which involves a decrease in water content of saturated soil without replacement of water by air".

Pioneers in the field of soil mechanics testing recognized early on that this predictable soil behavior would allow them to calculate the rate and amount of consolidation for a given load.
Therein an important consideration into the design of earthworks and structural foundations to soil consolidation testing was introduced. In the early 1900’s a loading device to measure one-dimensional deformation of soil samples was already in use.
And the OEDOMETER was developed to measure characteristics of soils in earthen dam slope failures. Which are concepts still in use today in soil consolidation testing.

Today, ASTM test method D2435, and its AASHTO equivalent T 216, are the most common one-dimensional soil consolidation tests performed. Soil samples mounted in specialized testing fixtures called consolidometers are positioned in consolidation load frames for incremental loading, where deformation of the soil sample is measured.

Consolidometers are testing fixtures in a variety of diameters (2 to 4in (50 to 100mm) diameter and 1in (25mm) height) that precisely hold a soil specimen between two porous stones for consolidation testing. All within a precision ring.

There are two types of consolidometers, Fixed ring consolidometers and Floating ring consolidometers. Fixed ring consolidometers have the sample ring fixed in place so the sample is loaded only from the top. Which is suitable for a wider range of soil types, including softer soils. Floating ring consolidometers have sample rings that are not fixed during use but supported by the friction of the specimen. Which is suitable for stiffer soils.

LOAD FRAMES
The prepared consolidometer is then mounted on the consolidation load frame for testing. Consolidation load frames provide a platform and loading mechanism for soil consolidometers by applying a stabilize and specified axial incremental load very quickly, without impact, and maintain those loads for a specified period of time.

There are two type of load frames: Dead-weight consolidation load frames and Pneumatic consolidation load frames. Dead-weight consolidation load frame provides accurate axial loads to the soil sample through a system of suspended hanging weights. Sample deflection can be monitored analog or digitally. And generally an experienced operator with practiced technique will produce more repeatable results using this method. The Pneumatic consolidation load frame use precision controlled compressed air to apply and maintain the entire range of consolidation test loads. Resulting in overall greater accuracy, efficiency and ease of use.

Measuring Load and Deformation
For dead-weight load frames, determining sample load is a matter of knowing the mass of the free weight(s), the loading ratio of the beam, and the surface area of the sample. (Managing finer adjustments can take time and requires manual manipulation of the weights.) For pneumatic machines, the pressure regulator control is adjusted to the desired sample load. (Fine adjustments are easier to make with the pneumatic devices.)

Monitoring deformation values for either type of consolidation test method can be performed in a number of ways including using mechanical and digital dial indicators, LVDTs and data collection system like Gilson's Data Acquisition Software that calculates and reports in accordance with ASTM and AASHTO standards.

For more information go to [ Ссылка ]








one dimensional consolidation test / soil consolidation example problems / consolidation test of soil ppt / oedometer consolidation test lab report / consolidation test graph / consolidation test analysis / consolidation test lab report excel / coefficient of consolidation / oedometer test / preconsolidation pressure / compression index formula / one dimensional consolidation test / normally consolidated clay / consolidometer / consolidation test lab report pdf / consolidation of soil ppt / soil consolidation example problems / degree of consolidation formula / consolidation test astm / consolidation geotechnical engineering / direct shear test machine / soil settlement pdf / consolidation cell / astm d5856 / consolidation test graph / objective of consolidation test / oedometer test procedure pdf / soil settlement pdf

свернуть