Description of activities

The Laboratory of Applied Geophysics 1 is equipped with instruments for the characterization of the physical properties of soils and rocks through the determination of electrical, elastic and thermal parameters, as well as of their variations related to changes in different physical-structural properties, such as porosity, fracturing, degree of saturation, humidity, etc.

In particular, soil, rock and building material samples are characterized by the estimation of the following physical parameters: electrical resistivity, chargeability, spontaneous polarization, elastic waves velocity, temperature. Measurements of the electrical and elastic parameters are generally performed by varying the water content, to obtain characteristic curves of the examined parameters as a function of the degree of saturation or the species and percentage of contaminants of the saturation fluid.

Micro-geophysics measurements on specimens simulating masonry materials are generally carried out by means of 2D or 3D investigations, for detecting changes in resistivity, spontaneous potential and seismic wave velocity, and by means of thermal infrared thermography measurements, for detecting temperature variations of the investigated specimen surface. The definition of these variations allows to characterize, through appropriate modeling of the acquired data, the endogenous causes of material degradation (i.e. porosity, cracking, delamination, humidity, etc.) in terms of depth, geometry and nature of the anomaly sources.

Laboratory equipment and supplies:

• STING R1 IP georesistivimeter (Advanced Geosciences, Inc.)
• KEITHLEY 2700 Multimeter / Switch System with 20 Channels Multiplexer module
• HP 6920B voltage generator
• HP 34401A high precision digital multimeter (1 mV) and resolution (0.0001%)
• FLUKE 8840A high precision ammeter (1 mA) and resolution (0.005%)
• CONTROLS E46 ultrasonic pulse generator
• Ultrasonic transducers with central resonance frequency of 54 kHz and 150 kHz
• HAMEG INSTRUMENTS HM 2005 analog oscilloscope
• PICO ADC-200 high speed analog / digital converter
• Precision balance
• Heating and drying oven
• Vacuum bell jar
• Vacuum pump
• Multielectrode geoelectric tomography system (with ECG electrodes) for microgeophysical measurements
• Specimens simulating architectural structures with defects

Research and teaching

The developed laboratory tests are aimed at contributing to different research topics in the fields of geophysics and applied geology and, in particular, for: landslide studies and analysis of slope stability; aquifer characterization, through the definition of functional relationships between geophysical and hydrogeological parameters; study of soil and groundwater pollution phenomena, through the definition of functional relationships between geophysical parameters and nature and concentration of pollutant elements; identification of endogenous causes of degradation of architectural structures for engineering and/or Cultural Heritage purposes.

The laboratory is also used for practical exercises in the teaching of Applied Geophysics and Electromagnetic Methods of Geophysical Exploration, and in orientation activities for high school students, as well as experimental activities related to the development of Master’s Degree and PhD theses.

Depressurization process of rock samples (a) and saturation by capillary rise (b).

Equipment for electrical resistivity (a) and P-wave velocity (b) measurements. (c) Oven for samples drying during a measurement cycle.