GEOPHYSICS TECHNOLOGY

Design and manufacturing of custom devices for studying Rock Mechanics

Biaxial and Triaxial press
Rotary machine
Friction devices

Equipped with:

Hydraulic system for confining and movement load
Mechanical system for high velocity movement
Electronic system for control and data acquisition

Custom specification under request:

Confining pressure
Confining temperature
Pore system pressure
Normal and tangential load
Speed and acceleration
Number of pistons for axial load
Sample holders

Example of similar equipment already supplied:

Confining pressure: up to 1000 bar
Confining temperature: up to 250°C
Axial Load: up to 150 KN
Pore pressure: up to 1000 bar
Speed: up to 30 mm/sec (with hydraulic load)
Acceleration: up to 3G (with electromagnetic motor)

Examples of most important equipments design and manufactured are:

BRAVA – Brittel-Rock investigAtionVersatile Apparatus

SHIVA – Slow to HIgh Velocity Apparatus

SHIVA - SLOW TO HIGH VELOCITY APPARATUS

SHIVA is capable of shearing ring-shaped samples at sliding velocities up to 9 m/s, accelerations of 40 m/s2 and normal stresses up to 50 MPa.

INGV performs experiments on rock samples of a variety of compositions using slip velocities and accelerations that simulate slip velocities function that occur during earthquakes.

In addition, TEES srl develop a pore fluid system and a pressure vessel in order to perform experiments that include the physical-chemical processes that occur during slow interseismic periods.

With this apparatus INGV is able to simulate the transient load variation expected during seismic failure on natural faults and measure the related dynamic weakening, frictional evolution and slip velocity on the sample.

Specifications:

Arm increases thrust to 50 kN or 70 MPa
Loadcell (full scale 50 kN, resolution 2.5 N)
measures normal load up to 70 MPa with 0.035 MPa resolution
Brushless engine: peak power 270 kW.
Rotation speed up to 3820 RPM.
Small engine: nominal power 5.15 kW.
Rotation speed up to 5790 RPM
Minimum sliding velocity of 1 μm/s

BRAVA - BRITTEL-ROCK INVESTIGATION VERSATILE APPARATUS

TEES designed and manufactured for INGV the prototype rock deformation biaxial apparatus to examine the physical properties of brittle rocks.

The apparatus is installed in the HP-HT lab at the INGV in Rome.

The machine (about 6Tons weight) consists of a stainless steel pressure vessel with internal diameter of 40 cm, equipped with 2 hydraulic pistons, horizontal for normal stress and vertical for shear stress.

The vessel was designed to be and maintain an internal pressure up to 850bar.

Five holes on the pressure vessel allow to connect up to 100 sensors close the sample when the portholes are closed.

Pistons are driven by two very sensitive voltage control signals servo-valve and can work independently in load or displacement feedback control, obtaining a sliding velocity into the range 0.1 μm/s – 2 cm/s between the samples.

Two load cells with a dynamic load ranging up to 150 Tons and 30Kg of sensitivity are mounted onto each vertical and horizontal pistons.

The apparatus has other three hydraulic pistons positioned on the kart, that operate as fluid pressure intensifier and they are controlled by three proportional valves.

The apparatus has other three hydraulic pistons; two are dedicated for the pore fluid circulation into each sample rock. One piston intensifier is used to keep the confining pressure of oil around to the sample.