ALBERT

Description: This chapter provides a general review of ongoing activities related to the geotechnical applications of the acoustic emission (AE) technique on various rock specimens. Recent and current worldwide AE studies are reviewed. This study highlights some key issues concerning the applications of many methods ranging from simple event counting with few AE sensors to complex focal mechanism investigations using multiple AE sensors.

Description: The pyramids on the Giza plateau close to Cairo in Egypt belong to the most important structures in the history of mankind. The Great Pyramid built by Pharaoh Cheops (Khufu) is about 4500 years old and was already described as one of the Seven Wonders of the Ancient World by the Greek historian Herodotus. Besides some deterioration throughout the centuries, the Cheops Pyramid has barely changed since its construction. It is one of the most visited and investigated structures on earth. However, few systematic investigations are reported using modern geophysical measurement methods. Based on findings during Muon measurements as part of the ScanPyramids project, a joint team from Cairo University and Technical University of Munich including researchers from different countries had the opportunity to perform three measurement campaigns between 2020 and 2022. These measurements have been part of a capacity-building training of young scientists and included ground penetrating radar (GPR), ultrasound, electrical resistivity tomography, passive seismic, and others. Some results are presented focusing on the pros and cons of the individual techniques considering the requirements of cultural heritage and the difficult measurement conditions: large blocks of limestone with strong surface deteriorations, joints of unknown conditions, sidewall reflections, and restricted access. Geodetical surveys determining measurement positions, image fusion, and numerical simulations have been of tremendous help to interpret the data and are also discussed.