This paper presents an outline of a historical stone: the Marble of Campiglia, from Tuscany (Italy). A comprehensive review of the literature and archival documents, combined with a new detailed field survey, allowed us to revise the geological setting and exploitation history of this cultural heritage marble, which has been sporadically utilized from Etruscan times to the present day. The Campiglia Marittima Marble (CMM) has a thermal-metamorphic origin associated with the intrusion of a granitic pluton dated to approximately 5.4 Ma. This process gave rise to a marble with peculiar textural, grain size, and fracturing characteristics that influenced extraction techniques and methodologies. The primary exploitation periods of the CMM as an ornamental stone were the Etruscan-Roman era, the Renaissance, and the nineteenth century; currently, it is used exclusively for industrial purposes. A significant number of ancient quarries are located on the western slope of Monte Rombolo, likely attributable to the high variety of commercial marble types available in the area and its strategic location, which facilitated transport routes to the Tyrrhenian Sea. This research aims to bring attention to this historical marble and may support, alongside the potential reopening of selected quarries for restoration purposes, the preservation of the authenticity of the historical artefacts in which it was employed.

The Tuscan marbles, primarily exposed in the Alpi Apuane Metamorphic Complex and the Montagnola Senese ridge, record a protracted deformation history spanning the rheological spectrum from ductile flow to brittle fracturing. While the syn-metamorphic ductile evolution of these units has been extensively studied, the subsequent brittle deformation—specifically post-metamorphic faulting and fracturing—remains poorly constrained. These fracture networks are not only uplift-related features; they record a polyphase brittle history with direct implications for fluid migration, quarry slope stability, and Neogene–Quaternary stress field reconstruction.In this work, we characterize brittle structures within marble from the Montagnola Senese, located along the Mid-Tuscan Ridge in the Northern Apennines. This marble has been quarried since Roman times, making rock mass characterization relevant for both scientific and practical purposes. We adopt a multidisciplinary approach, integrating classical field surveys with 3D digital outcrop models obtained by photogrammetry. Data were collected at the outcrop scale and subsequently extrapolated to define the fracture pattern across the entire Montagnola Senese ridge.The detected fractures and faults cut the marble schistosity, therefore post-dating the last metamorphism event (middle Miocene). Our results reveal at least two brittle deformation phases: (I) a first, left-lateral strike-slip system, followed by (II) extensional structures, which crosscut or reuse the previous ones. Fracture attributes, such as fracture intensity and density, within the non-faulted rock mass were compared to those associated with fault damage zones. These data provide constraints on both quarrying operations and fluid circulation models, whilst contributing to the definition of the tectonic setting of this sector of the Mid-Tuscan Ridge from the middle Miocene to the present day.

Among the non-destructive and non-invasive techniques, the Ground Penetrating Radar (GPR) is widely used to investigate shallow subsurface. GPR analysis is based on the propagation of electromagnetic waves and reconstruction of the medium is based on measurement of the elapsed time between transmission and reception of the impulse. Resolution and investigation depth are closely related to frequency of the signal, as the frequency increases, resolution increases and depth of exploration decreases. Since, several decades, GPR was mostly used for the reconstruction of the geological features of the shallow subsurface and the detection of pipes, tunnels or hidden objects. More recently, thanks to the applications of higher frequency antennas, GPR has been used successfully to reconstruct structural features of buildings and masonry structures, providing critical information especially for historical buildings that underwent multiple construction processes and that are commonly missing detailed architectural information. For this reason, the application of this technique on historic buildings becoming more and more popular. In this study, we present GPR analysis performed in the San Giovanni’s Baptistery in Firenze, that was built during the XI-XII centuries and totally covered by white and dark-green marbles and was object of conservation measurements through centuries under the supervision of the Opera del Duomo (OPA), with the most recent major conservation works performed around 1930. The Baptistery’s interior cover consists of a pseudo-dome, and its external roof is shaped like a pyramid with eight pitches. Due to the lack of detailed documents concerning its masonries structural and textural assemblages, the GPR was performed with multiple antennas (by IDS Georadar, part of Hexagon) in single or array configuration (copular and crosspolar antenna disposal) on the entire structure of the edifices and focusing particularly on the roof and the extrados of the inner dome. The data were processed using GRED HD software, allowing to produce 2D and 3D pictures (tomographies) and allowing to define thickness and structure of the roof, inner dome and walls, so providing new information required to correctly plan focused conservation intervention. This study is performed in the framework of the HGP (Heritage Ground Penetrating Radar) project (CUP:B55F21007810001) funded withing the Next Generation EU program.

The San Niccolò’ Tower-Gate in Florence, designed by Andrea dell’Orcagna, was built in 1328 as part of the third ring of the city walls of Florence. In the frame of a conservation project promoted by the Municipality of Florence, Belle Arti Office, the Department of Earth Sciences of the University of Florence conducted a series of studies, using NDT and LDT (No Destructive Test, Low Destructive Test) techniques, to characterize the tower’s masonry. The knowledge path followed the Italian Guide Line emitted by the Ministry of Culture for the conservation of historical buildings and the principles established by the International Restoration Charts. This knowledge path had already been tested and followed for the study of several other historical Florentine cultural heritage buildings. The first step regards the geometric survey and the 3D H-BIM restitution. Particular attention had been paid to the geological and foundation setting as an integral part of the building and to the local seismicity, too. The definition of the masonry structure and assemblages had been performed by using seismic, georadar, sonic, and sclerometric investigations. The Tower-Gate’s masonry results showed it to be very well constructed, being in the standard of the historical Florentine buildings of that time. After eight centuries since its construction, the San Niccolò’ Tower-Gate displays a good conservation condition according to the principles of Integrity and Authenticity.

Nell’ambito di un generale Accordo Quadro di collaborazione tra Opificio e DST, ex Art.15 L. 241/1990, è stato sviluppato un programma di studi e ricerche propedeutici alla verifica sismica della sede dell’Opificio in via degli Alfani 78 a Firenze. Seguendo il percorso di conoscenza definito dalla Linee Guida MIBACT 2011 sono state eseguite indagini NDT per definire la struttura ed i materiali di murature ed impalcati. In particolare per questi ultimi sono state eseguite numerose indagini georadar con varie strumentazioni che hanno portato ad identificare la stratigrafia e la tipologie degli impalcati presenti. Su questa base è stato creato un abaco di riferimento con il quale sono state quindi mappati i solai delle varie stanze al fine della loro verifica sismica.As part of a general Framework Agreement for Collaboration between the Opificio and DST, pursuant to Article 15 of Law 241/1990, a program of studies and research was developed preparatory to the seismic assessment of the Opificio headquarters at Via degli Alfani 78 in Florence. Following the knowledge process defined by the 2011 MIBACT Guidelines, NDT surveys were conducted to define the structure and materials of the walls and floors. Specifically, for the latter, numerous georadar surveys were performed with various instruments, which led to the identification of the stratigraphy and typology of the existing f loors. On this basis, a reference schedule was created, which was then used to map the f loors of the various rooms for their seismic assessment

The roadway instability and intense movement of overlying strata created by underground mining in thick coal seams seriously affect safe production and the surface environment. In response to these issues, this study systematically investigated the space compensation effect in goaf areas induced by roof directional pre-splitting technology (RDPT) and its control mechanisms on roadway stability and surface subsidence, employing a comprehensive approach that included theoretical derivation, physical experiments, numerical computations, and engineering verification. A goaf fragmentation-compensation equation and mining damage conservation law were established based on the short cantilever beam (SCB)-gangue expansion synergistic bearing model, elucidating the mechanical mechanism by which RDPT achieved immediate volume filling compensation through enhanced fragmentation expansion coefficients in the caving zone. Field tests demonstrated that compared to non-RDPT areas, RDPT implementation areas showed 0.8 increases in both initial and residual fragmentation expansion coefficients. Significant improvements were observed in key indicators: roof-floor displacement decreased by 50.5

The estimation of the Floor Response Spectrum (FRS) is fundamental for the characterization of the seismic demand at different heights of a structure, particularly for assessing seismic safety of both local mechanisms and non-structural elements. This paper aims to provide insight into the assessment of floor response spectra in masonry towers by presenting and discussing the results of an investigation carried out on the San Niccol & ograve; Tower in Florence, Italy. To determine the tower's dynamic properties, Ambient Vibration Tests (AVT) and Operational Modal Analysis (OMA) were conducted, that revealed a complex structural behaviour influenced by geometric irregularities and material heterogeneity. The floor response spectra were evaluated using three complementary approaches: (i) a simplified analytical formulation provided by the latest Italian Standards, (ii) an experimental method based on seismic interferometry, and (iii) a numerical approach based on Finite Element (FE) linear time-history analyses. The comparison of results from these procedures shows that, while code-based simplified formulations offer a practical tool for preliminary estimation of floor response spectra, they can be highly sensitive to modal parameters, which may significantly influence the predicted seismic demand. In this respect, this study stresses the importance of integrating experimental and numerical methods for a more reliable evaluation of FRS in slender historic structures.

To tackle stress concentration and resource waste in coal mining, this study proposes an innovative non-pillar retained roadway (NPRR) method. It integrates three core components: negative Poisson’s ratio (NPR) anchor cable support, directional pre-splitting technology (DPT), and an adaptive temporary support system. The approach employs staged stress compensation, synchronized with mining phases. It eliminates protective pillars and optimizes the surrounding rock stress environment. Multi-scale validation included laboratory experiments, numerical simulations, and field trials. Results showed: (1) NPR anchor cables provided continuous radial stress compensation, high pre-stress, and large elongation. (2) DPT reduced stress levels and optimized the stress environment in the surrounding rock. (3) Temporary support controlled dynamic convergence during goaf compaction. Compared to conventional pillar-based methods, this strategy reduced excavation volume by 50

A critical review of studies concerning the attribution of the provenance of marble from the Apuan Alps (Italy) (AAM) used for historical–monumental buildings and artefacts is proposed based on its O/C isotopic and EPR signature. First, a summary of the geological origin of AAM and its geo-structural evolution and setting is presented. A review of the exploitation history of AAM is then discussed. This geological and historical information is used as categorical information to better constrain the literature multimethodic database, containing numerous data, including O/C isotopic and EPR spectroscopic parameters. A robust multivariate statistical analysis of the combination of all these data is performed. The results point to the fact that the O/C isotopic and EPR signature can help in attributing an analysed AAM sample to a marble extraction district, and to a certain extent also to a site, whereas the discrimination of the individual quarry appears to not yet be achievable.

The San Niccolò’ Tower-Gate in Florence, designed by Andrea dell'Orcagna, was built in 1328 as part of the third ring of the city walls of Florence. In the frame of a conservation project promoted by the Municipality of Florence, the Department of Earth Sciences of the University of Florence conducted a series of studies, using NDT techniques, to characterize the tower's masonry. Based on geological, seismic, georadar, sonic, and scleometric investigations, the Tower's masonry was found to had been excellently constructed and, after eight centuries, remains in good condition.

Research on the failure behavior of Longmaxi shale is vital for shale reservoir reconstruction. Shale inherently contains some initial micro-cracks, which significantly affect its strength and failure behavior. In this paper, a refined boundary multi-level parallel bonded grain-based model (multi-level PB-GBM) in Particle Flow Code (PFC2D) was developed, and the effect of inherent initial damage on shale strength and failure behavior was quantitatively investigated. The results showed that inherent initial damage significantly influences the failure pattern and mechanical properties of shale. The newly generated cracks of the initially damaged samples are significantly self-organized compared with those of the undamaged samples, indicating that the inherent initial damaged cracks induce the orientation and aggregation of micro-cracks. High initially damaged samples mainly demonstrate by splitting-shear coupled fracture as a result of the co-evolution of primary and secondary microcracks. Generally, rock strength gradually decreases as the initial damage increases. When the inherent initial damage within the sample is low, the rock strength is greatly influenced by confining pressure, whereas when the initial damage is high enough, the initial damage contributes more to the rock strength.

The 110-mining method, a rising and revolutionary non-pillar longwall mining method, can obviously expand coal extraction ratio and minimize roadway incidents. However, in case of composite hard roof, problems such as difficulty in commanding the entry steadiness and insufficient fragmentation and bulking of the goaf gangue are prevalent. In this study,a 110-mining method for roadway surrounding rock stability control technology based on a compensation mechanism was proposed. First, the composite hard roof cutting short cantilever beam(SCB) model was built and the compensation mechanism including stress and space dual compensation was studied.Subsequently, the controllable elements influencing the roadway steadiness were confirmed to consequently put forward a control technology based on stress compensation for entry support and space compensation for the fragmentation and bulking of goaf gangue. The control technology was finally verified through onsite engineering experiments in terms of composite hard roof. The adoption of the 110-mining method with compensation control technology indicated good support effect on the roadway. The initial and residual expansion coefficients of the goaf gangue increased by 0.6 and 0.6, respectively, and the maximum and average working resistances of the working face support decreased by 10.9% and 13.8%,respectively. Consequently, the deformations of reserved entry decreased, and entry steadiness was enhanced. The presented technique and effects got probably have practical values for non-pillar mining functions in comparable field.

In the field of conservation and protection of heritage buildings, knowledge plays a fundamental role, emphasized by national and international rules and regulations. This aspect becomes fundamental when conducting the structural assessment of a historical building. This study envisaged a cognitive phase via the application of advanced survey and diagnostic methodologies to define the materials, construction techniques, and state of conservation of the structural system of a specific building forming part of Florence’s heritage. The information complex produced formed the basis for the structural assessment and for the experimentation of the BIM methodology within the creation of databases for the management of cognitive processes of historical buildings. The case study is one of the gates of the last circle of walls of the 14th century and is the only one that has maintained its original height, despite modifications: the gate/tower of San Niccolò. The research conducted, in addition to achieving a structural assessment of the tower, has allowed the creation of a dynamic model for organizing and consulting the information, laying the groundwork for the creation of a conservation and maintenance plan.

To overcome large deformation of deep phosphate rock roadways and pillar damage, a new type of constant-resistance large-deformation negative Poisson's ratio (NPR) bolt that can withstand a high pre-stress of at least 130 KN was developed. In the conducted tests, the amount of deformation was 200–2000 mm, the breaking force reached 350 KN, and a high constant-resistance pre-stress was maintained during the deformation process. A stress compensation theory of phosphate rock excavation based on NPR bolts is proposed together with a balance system for bolt compensation of the time-space effect and high NPR pre-stress. Traditional split-set rock bolts are unable to maintain the stability of roadway roofs and pillars. To verify the support effect of the proposed bolt, field tests were conducted using both the proposed NPR bolts and split-set rock bolts as support systems on the same mining face. In addition, the stress compensation mechanism of roadway mining was simulated using the particle flow code in three dimensions (PFC3D)-fast Lagrangian analysis of continua (FLAC3D) particle-flow coupling numerical model. On-site monitoring and numerical simulations showed that the NPR excavation compensation support scheme effectively improves the stress state of the bolts and reduces the deformation of the surrounding rock. Compared to the original support scheme, the final deformation of the surrounding rock was reduced by approximately 70%. These results significantly contribute to domestic and foreign research on phosphate-rock NPR compensation support technology, theoretical systems, and engineering practices, and further promote technological innovation in the phosphate rock mining industry.

Research on the failure behavior and hydraulic fracturing mechanism of Longmaxi shale is vital for deep shale gas exploitation. The anisotropic properties of shale, especially bedding properties, significantly affect its cracking behavior. In this study, by embedding the smooth joint model (SJM) into the parallel bond model (PBM) in two-dimensional particle flow code (PFC2D), uniaxial compression and fluid–solid coupling hydraulic fracturing models with different bedding properties were quantitatively established, and the effects of bedding properties on the failure behavior and hydraulic fracturing mechanism of Longmaxi shale were investigated. The results demonstrated that bedding properties significantly affect the failure pattern, strength response and hydraulic fracture propagation of shale. Shale failure is controlled by bedding inclination, bedding strength, and maximum principal stress, which mainly depends on their competition mechanism. In addition, it is found that the secondary induced fractures associated with primary through-bedding fractures tend to have larger fracture networks compared with those associated with primary along-bedding fractures.

This study investigates the role of complex networks of discontinuities (bedding, joints, fracture, and faults) for fluid flow dynamics within carbonate rock masses. Understanding and modelling how discontinuities interconnect and interact is crucial for resource management industries (e.g., geothermal energy and carbon capture), as well as for managing problem of water inflow during tunnelling. Our methodology integrates fieldwork studies with remote sensing techniques, including ground and drone-based photogrammetry, to build accurate models of discontinuity networks. We present how using machine and deep learning algorithms for semantic segmentation improves the identification of discontinuities in photogrammetric data and minimises biases induced by manual identification. This approach provides fast and reliable tools, essential in resource management and tunnelling operations. By merging theoretical insights with practical applications, we provide a comprehensive framework for understanding and modelling rock mass flow dynamics, vital for both management of engineering works and sustainable resource use.

The Monteferrato area is the source site of "Verde Prato" that, together with Carrara Marble, forms the visual duotone that typifies Renaissance buildings in Tuscany. Verde Prato is a serpentinized peridotite that crops out close to Figline di Prato. At the beginning of the 20th century, Gustav Steinmann visited and described the ophiolitic outcrops of Figline di Prato, which contributed to his recognition of the "Steinmann Trinity", i.e., the common co-occurrence of serpentinites, pillow basalts and cherts. The Steinmann Trinity concept, in turn, formed an essential step in the development of ophiolite theories, sea-floor spreading, and plate tectonics. Because of the cultural, artistic and geologic importance of the Monteferrato serpentinized peridotite, the Tuscan Region classified these quarries as historical sites in its list of the Historical Ornamental Stones Quarries. Within the Monteferrato serpentinites, large portions of the original peridotite are locally partially preserved, still presenting original microstructure of the mantle protolith. These peridotites preserve vestiges of subcontinental mantle deformation that occurred during the early stages of lithosphere extension, which opened the Ligurian Tethys in the Early Jurassic. Static crystallization of peridotitic minerals was followed by bulk serpentinization. Successive veins formed, filled by chrysotile and lizardite, with the former cutting the latter. Antigorite is also present in veins, but crosscutting relationships with the other veins are unclear. A tentative interpretation of the veining events relates the antigorite vein formation associated with the gabbro intrusions into the serpentinized peridotite, while the transition from chrysotile to lizardite relates to the activation of an extensional tectonic regime, perhaps linked to the closure of the Ligurian Tethys and bending of the subducting plate. Serpentinization may also provide the key to understand how the Monteferrato peridotites were ultimately emplaced within the Monte Morello Unit.

Purpose The paper is aimed at assessing the safety of the Giotto's Bell Tower, with special attention to its foundation system, i.e. the foundation works and soil. The tower, well known all over the world, has a squared plan, with sides of 14.45 m each, and a total height equal to 84.7 m. The structural response of the tower is assessed with reference to the gravitational load and to the expected seismic action, quantified according to the seismic hazard of the site and the foundation soil. Design/methodology/approach A simplified analysis has been performed to check the safety level of the tower to seismic actions. Special attention has been paid to quantify the horizontal actions representing the seismic loads. Such quantification, indeed, has been made both through the elastic spectrum of the tower and by performing a site response analysis on the foundation soil, represented as a one-dimensional stratification of soil layers, described on the basis of experimental investigations. After defining the loading actions, a simplified assessment of the foundation safety has been made by considering the action over foundation, the geotechnical data and the safety factor. Findings The findings of the paper concern the assessment of the safety of the tower's foundation system. A lot of experimental data on the foundation soil, provided by various geological investigations, have been provided and used for the assessment. Moreover, the mechanical properties of the materials used for the structure have been collected and shown in the paper. Originality/value The paper collects a lot of technical information regarding the Giotto's Bell Tower, both regarding its foundation soil and the constituting materials. On the basis of the collected information, a structural analysis has been made to assess the seismic safety of the tower, and the results of such assessment are provided and discussed.