In order to implement civil engineering structures, engineers must take into consideration different types of soil properties as basis for their calculations.
This section provides all the instruments needed for the analysis of soil samples and thus predict future behavior, proposing a complete range of soil testing equipment for sample sampling, classification, consolidation, direct shear strength, triaxial strength, compaction, penetration, bearing capacity, permeability, density, geotechnical and chemical tests, in compliance with the main International Standard including EN, ASTM, BS.
Soil Mechanics – Consolidation
The one-dimensional consolidation test, or oedometric test, provides information on the compressibility of a sample restrained laterally while subjected to vertical load. The test can be performed in order to determine the correlation/ratio between the applied pressure and the resulting deformation, or between vertical deformation and time during which a constant pressure is applied. A cylindrical sample is inserted in a non-deformable metal ring and placed between two porous stones (to ensure water drainage and optimal amount of moisture).
Two versions of Oedometer are available: a version with manual application of weights typically used for educational purposes, and a version with fully automatic loading steps application.
Soil Mechanics – Shear
The shear test on soil specimens is performed to measure the resistance to shearing of all those specimens subjected to an orthogonal pressure to the plane.
The sample is placed between two porous stones and metal grids inside a sturdy metal box divided into two halves.
Different versions of shear testing machines are available, from the basic version used for teaching purposes with vertical load application through calibrated weights and dial gauges, to the most advanced and high-performing shear testing machine with fully automatic vertical load application.
Shear speed is applied by means of an electric motor and can be set or calculated automatically according to the consolidation obtained.
Soil Mechanics – Triaxial
The triaxial test brings the sample back to its site conditions through the various steps characterizing the triaxial test (saturation, consolidation) and measure the material resistance to shearing and the connections between stress and strain.
During the standard triaxial test the sample is die-cut or reconstructed in a cylindrical shape, wrapped by an impermeable membrane, laterally confined by hydraulic pressure inside a cell and finally subjected to an axial load which generates the sample breaking.
Various standard triaxial systems, from teaching purposes to advanced laboratory needs, are available complete with dial gauges, dynamometric rings and data acquisition systems for the upgrading.
The Automatic Static and Dynamic triaxial machines complete the range, equipped with control units and first level software which can be completely programmable and controllable remotely.
Field Penetrometers
Available several models of field penetrometers:
- Dynamometric ring penetrometers: for measuring static penetration
- Proctor Penetrometers: for measurement of the degree of compaction of a soil sample
- DCP and lightweight dynamic penetrometers: for determining the geomechanical properties of road pavement layers.
Pocket Penetrometers & Shear Vane Devices
For a rapid evaluation of the compressive strength and the cohesion of soil, various models of pocket penetrometers and shear vane devices are available.
Particle Size Analysis
Complete set used to determine the quantitative size distribution of very fine particles in soils such as clay and silt, having diameters less than 0.075 mm or 0.063 mm.It consists in measuring the time it takes for particles to sediment inside a graduated cylinder. Readings are taken using a soil hydrometer.
Sand Equivalent Test
Comprising a portable test set, it is used to determine the “sand equivalent” value of fine and coarse aggregates.
In order to perform the test it is necessary to shake a test cylinder containing stock solution by hand or automatically using a special mechanical shaker.
Specific Gravity and Water Absorption
Basic equipment to carry out specific gravity and water absorption of fine aggregates.
Atterberg Limits
Water content corresponding to “conventional” passage between different states is defined as Atterberg Limits which vary from one type of clay to another. Thus a clayish soil may appear in one of four states: Solid, Semi-solid, Plastic and Liquid.
Atterberg Limits have been defined and particular procedures created that use specific test equipment such as the Casagrande and Cone Penetrometer Methods.
Specimen Preparation
In order to achieve optimal test results, specimens must be adequately prepared and for this purpose it is necessary to use the correct equipment for each type of test.
Specimen Extruders
Various extruders are available for easily removing the specimens from the sample containers or cutters, including both hand-operated and hydraulic models.
Proctor Test
Where compacted samples are needed, such as density and moisture tests, soil molds are used.
Automatic Proctor CBR Compactors
Fully automatic compactors are used for compacting soil accurately and quickly.
Different size molds may be used with interchangeable compaction hammers.
CBR Frames and Equipment
Various models of loading machines are available for performing CBR test, from the simplest hand-operated models with analog readout to the fully-automatic digital models with integrated data acquisition.
A wide range of accessories necessary for the test are also foreseen.
Universal Multipurpose Testers
Universal testing machines can be deemed an essential choice for any laboratory. Capacity may be selected between 50 kN and 200 kN.
Both have an integrated data logger for data acquisition via transducers, data storage on USB pen drive and SD card as well as software for communication to a PC.
Load Rings and Dial Indicators
Load rings are used for load compression measurement applied by the testing machine. Made from hardened alloy steel, they are chrome-coated and complete with upper and lower coupling blocks having M10 female gas thread. The accuracy is ± 1% of applied load and repeatability is within 0.2% Each ring is supplied complete with calibration chart.Large range from 0.5 kN to 100 kN in the following versions:
- S370 Serie with dial gauge 0.01 mm graduation
- S371 Serie with dial gauge 0.001 mm graduations
- S372 Serie with digital gauge 0.001 mm graduations, with RS232 port and battery.
Load Cells and Displacement Transducers
Electrical equipment for automatic readings. Made of high quality materials, they are strongly recommended when high accuracy in testing is required.
Electric and strain gauge load cells must be connected to the automatic data acquisition system mod. S334.Transducers are provided with cable, connector and signal conditioner.
Moisture Condition Apparatus
This apparatus is used to measure the minimum comparative effort required to produce near full compaction of a soil, and the rate at which a sample of chalk lumps are crushed. The unit can be used to classify chalk as a fill material with saturated moisture content. The apparatus comprises a robust frame where a rammer falls, mold, scale, counter, accessories.
Chemical and Water
Comparative tests methods based on chemical and organic analysis of soils in general.
Field Density
The sand cone equipment is very useful to evaluate the in-place density of soils having maximum particle size of up to 51 mm.
It is possible to use big and small samples using different capacities set.
Advanced Compaction and Density
Advanced technologies are used to accurately measure density and percentage of compaction of soil in the field where intuite and quick operations are necessary.
The information given is useful to have a fast target of the soil under test, values that can be useful for further tests like Proctor or Marshall.
The instrumentation of this sector is easy to use and does not require an electrical supply.
Relative Density of Cohesionless Soil
The apparatus of this section is used to determine the relative density of cohesionless soils when conventional compaction testings are not satisfatcory.
This method is really useful in case of soils with free-draining properties through vibratory compaction.
Clegg Hammer
This apparatus is used to obtain an indication of the degree of compaction of soil. Recorded valves can be directly correlated to the CBR test method.
User can quickly enable/disable the readout unit to calculate the 4th drop % CBR following Dr. Clegg’s revised and updated equation with inter-drop CIV check TREND algorithm. Main features:
- Well-proven and stable components.
- Easy to use, no set-up is required.
- Back lit highly readable alpha numeric display.
- Optionally fitted Bluetooth with PC Software to allow data transfer of CIV, %CBR, time and data of up to 10000 drop tests.
Vibrating Compaction Hammer
It provides an alternative method for the compaction of soil samples in the determination of dry density/moisture content relation (called Proctor), unconfined compressive strength of stabilized soils and CBR tests. This hammer is also used for the compaction of asphalt in the percentage refusal density and for compacting concrete cube or beam samples.
Plate Bearing Test
Plate bearing test is used in earthworks and soil foundations to evaluate the composition and consequent deformability of the soil. This gives an indication of the total load capacity of the soil under test. Also used in road construction engineering.
Permeability Test
Soil permeability is formally expressed using a coefficient which can be measured by constant head and falling head methods. The two methods can be used with granular soils as well as with clay and sand.
Strength of Stabilized Soil
These tests are carried out with the aim to determining the unconfined compressive strength of soils with medium grains and fine ones through different set for different specimen measures.
Geophysics
Basing on seismic refraction or reflection methods, this technique is useful to deal with physical properties of soil and to draw precise soil layers according to the response of each one to the seismic signals. The information achieved is commonly used for further calculations of parameters using literature correlations.
