Oedometers for Soil Consolidation Testing

  1. Home
  2. Soil Mechanics Testing Equipment
  3. Oedometers for Soil Consolidation Testing
Oedometers for Soil Consolidation Testing
Request Quote Get Catalogue

Soils settle under load, and the oedometer measures how much and how fast. A specimen restrained laterally is loaded vertically in successive increments while water drains through its faces, and the compression and its rate are recorded. The results feed settlement and consolidation-rate estimates for foundations, embankments and structural fills. Incremental consolidation is described in ASTM D2435 and BS 1377-5, and the standard gives two alternative procedures: one with constant load-increment durations and one that advances each increment after primary consolidation. A consolidation series can run for days, so frame stiffness, load accuracy and how little the operator has to touch between steps decide how repeatable the series is.

Two loading methods are offered. The classic frame uses a lever arm carrying dead weights, with a rigid aluminum alloy structure and three lever ratios so one weight set covers a wider stress range. Pneumatic loading removes the weights: a servo-controlled air system applies the increments automatically, around the clock, with results shown live on a PC. Both accept standard consolidation cells in a range of specimen sizes, and both can produce a digital record. The same cell on the front-loading frame serves the consolidation test and the permeability test. Cells, gauges or transducers and software are ordered to suit the specimens. Installation, calibration and training come from NextGen engineers.

Read More...

What a Consolidation Test Measures

A consolidation test shows how a soil specimen compresses over time under stepwise vertical loading, with drainage allowed vertically and sideways deformation prevented. The compression curve gives the magnitude of settlement, and the time readings give its rate. Engineers use both to estimate settlement under structural fills, embankments and foundations. The response is sensitive to specimen disturbance and saturation, so specimen handling matters as much as the frame.

Swelling can be studied on the same equipment: the ACE drives incremental consolidation and one-dimensional swell tests pneumatically, and a time or step basis can be programmed for the end of each test.

Standards and Test Methods

ASTM D2435 describes incremental loading consolidation in an oedometer or consolidation cell and gives two alternatives. Test Method A uses constant load-increment durations, commonly 24 hours or multiples, with timed readings on a minimum of two increments. Test Method B takes time and deformation readings on all increments and advances each one after primary consolidation. BS 1377-5 covers compressibility, permeability and durability tests for soils, and the same NG-Oedometer cell serves both the standard consolidation test and the permeability test.

Choosing a Loading Method

The NG-Oedometer applies load through a lever arm with hanger positions for 9:1, 10:1 and 11:1 ratios. At 11:1 it reaches 9.061 MPa on a 20 cm2 specimen of 50.47 mm diameter, and a weight application guide pairs each cell, beam ratio and weight set. The ACE oedometer loads pneumatically through a servo-valve to 15 kN, runs tests 24 hours a day, and one PC can control up to 60 ACE units. It needs compressed air at up to 10 bar, and a compressor is available where the laboratory has no air line.

Consolidation Cells and Accessories

Cells are chosen by specimen size, from 50.47 mm diameter and 20 cm2 up to 112.80 mm diameter and 100 cm2, and each carries its own calibration disk on the automatic frame. Consolidation cells, weight sets, gauges or transducers, software and PC are listed as separate items, so the quote is built around the specimens. The front-loading frame adds a screw jack support that takes the load while the specimen and cell are being set up. Reporting on the automatic frame uses Geo-Analysis templates that conform to BS or ASTM standards.

For Laboratories

One partner to equip your complete soil mechanics laboratory

Soil testing rarely stops at one machine. NextGen equips the whole geotechnical laboratory, from consolidation and shear testing to triaxial systems, vane apparatus and moisture determination, and stays responsible for it after delivery.

  • Equipment, fixtures and software
  • Installation, training, calibration
  • Lifetime technical support

Build My Soil Lab

Products

2 products

Nothing matches that filter. Show all products

FAQs

The argument for the automatic ACE is time rather than accuracy alone: a consolidation series runs for days, and every load change made by hand is a chance for it to drift. The ACE runs 24 hours a day and one PC controls up to 60 units. The front-loading frame covers the same standards at a lower cost per position and has a compact footprint, which suits a bank of frames.

Yes. The NG-Oedometer can be fitted with linear potentiometric transducers and connected to a data acquisition unit, so a mechanical frame still produces a digital record. The ACE takes a displacement transducer and a load cell on two analogue channels, with closed loop feedback, and shows results live on the PC. Data can then be processed with Geo-Analysis templates that conform to BS or ASTM standards.

Five cell models cover specimens from 50.47 mm diameter and 20 mm height (20 cm2) through 63.50 mm, 71.40 mm and 75 mm to a 112.80 mm diameter specimen of 25 mm height (100 cm2). The ACE frame accepts standard cells from 50.47 to 112.80 mm diameter, and the NG-Oedometer weight guide lists the same five cell models. Each cell on the ACE carries its own calibration disk.

Compressed air. The ACE loads through a high precision pneumatic servo-valve and needs an air supply of up to 10 bar. Where the laboratory has no air line, the NG-D2015 compressor of 13.2 gallons (50 L) can be used. Consolidation cells, Geo-Analysis templates, test software and the PC are not included and are ordered separately, so tell us the specimen sizes and how many positions you plan to run.

The NG-Oedometer has three hanger positions on the lever arm, giving ratios of 9:1, 10:1 and 11:1, so the same weight set covers a wider range of stresses. The maximum load is quoted at 11:1: 1,848 kg, which is 9.061 MPa on a 20 cm2 specimen of 50.47 mm diameter. A weight application guide on the page pairs each consolidation cell with its beam ratio and weight set.