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The cellars are usually the result of previous quarrying activities. The area of these cavities
nowadays located under urban areas and usually makes difficult the urban developments.
There are some areas in Budapest where cellars are found below future construction sites
therefore detailed investigation of these cellar systems are required. The inv...
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... The stability of these openings are always in question, especially when they are used as tourist attractions (Rybár et al. 2017). Construction activity above these abandoned quarries and galleries causes the additional load, which lead to further stability problems to these openings (Zenah et al. 2019;Zenah and Görög 2021). Therefore, a detailed geotechnical investigation is necessary in such cases. ...
... There are several software codes dealing with geotechnical analysis, such as MATLAB (Mollon et al. 2010;Janič et al. 2019), Rocscience (RS2 Bukaçi et al. 2016;Zenah et al. 2019), Examine (Andersson et al. 2004)), FLAC3D (Emad 2017), Abaqus (Sharma et al. 2018). The stability of this kind of cavities depends on several factors, such as material and rock mass properties, changes in the stress and geometrical characteristics (Cała et al. 2016). ...
... Rocscience (RS2) program was used for the calculations, one of the roc-science software packages; it is a 2D finite element program for soil and rock applications. RS2 can be used for: excavation design, slope stability, groundwater seepage, probabilistic analysis, consolidation, and dynamic analysis capabilities (Zenah et al. 2019;Bukaçi et al. 2016). Those calculations were done in different cases. ...
There are historic subsurface dimension stones in the capital of Hungary (Budapest) that were excavated in porous limestone. The stability of these subsurface openings is important, since most of them are located in urban areas, where existing buildings or new structures are planned to be built. The paper presents a detailed study considering the geometry of the system and the mechanical parameters of the limestone. The geometry of the cellar system was obtained using terrestrial laser scanning (TLS). The cover beds are few meters in thickness, and the width of the pillar is between 2.50 and 3.98 m, according to the measurements. The rock mass parameters which were used in the calculations were obtained from laboratory tests. A finite element (FEM) software Rocscience (RS2) were applied to model the stability of the galleries. Calculations were made for various geometries taking into account the thickness of cover beds and the width of pillars. Altogether 70 models were made. A surface load of 150 kN/m2 was also applied to model the buildings. New relationships between cover bed thickness, pillar width and displacements are outlined to compare these results to previous works. The strength reduction factor was also calculated for all geometries, indicating the changes in the stability of these underground quarries and pointing out the importance of cellar geometries.
... A lot of modelling software are used to evaluate the stability of the cavities, like MATLAB [11], FLAC [12], and Rocscience software [13] [14] [15]. In some cases, the collapse of cavities located in a [16], those collapses cause a loss in properties and lives. ...
Construction work above previous mining area is always a great challenge from the engineering point of view. In the southern part of Budapest, the previous mining activities resulted more than a hundred thousands of square meters of cavities. These cellars cut into porous limestone with different depth, but mostly close to the surface; nowadays, these cellars are located inside a residential area, and some part of the undermined area is planned to build because this is an empty and valuable area. For the construction of these improvements, it is necessary to perform detailed investigations and stability calculations.This paper is introducing the detailed investigation process of a significant cellar which will be involved by construction activities. Three buildings are planned to build above it. The studied cellar located in the 22nd district of Budapest, Hungary, with a depth between 4.3 – 7.7 m, with a wide range of pillars’ width between 0.73 – 7.7 m according to the studied cross-sections. The investigation starts with geometrical measurements and core drillings to map the rock mechanical properties of the host rock. Several laboratory tests were done for obtaining rock mechanical parameters for modelling. After creating the geotechnical model, it was used for FEM calculations using RS2 software. Four cross-sections were chosen across the cellar system in different locations and
various directions modelling the surface load of the planned building. The stability of the cellar was studied from two different viewpoints: firstly, the factor of safety was determined, and secondly, the settlement was calculated as an effect of the surface load. A displacement measurement system was set up in several cross-sections of the cellar to compare the calculated and real displacements in the future.
Keywords. undermined area, cellar, porous limestone, FEM modelling, safety factor
... Subsurface openings such as human-made cellars or natural caves are common in urban areas worldwide and can endanger human life and the built environment when these structure collapse (Marschalko et al., 2012). Cellars are known from France (Al Heib et al., 2015;Smeray et al., 2000), Spain (Fuentes et al., 2010), Italy (Ciotoli et al., 2015) and from Hungary (Görög et al., 2013;Vamos et al., 2015;Zenah et al., 2019). The construction period (from Roman times to present) and the excavation methods are different, but in most cases, these structures are cut in rocks without additional support. ...
... A similar set of cellars are found in the cities of Hungary, representing various ages from the Middle Age to the 19th century (Gálos et al., 1981). These cellars are found at different depth located close to the surface (Görög et al., 2013;Zenah et al., 2019), or at greater depth (Gálos et al., 1981). The usage of the cellars also varies from agricultural utilisation like wine storage (Fuentes et al., 2010) and mushroom production, or public spaces hosting social and cultural events (for example, restaurants) or even smaller openings that are used as water-sewer systems (Marasović et al., 2014). ...
... It compares mechanical parameters of this Hungarian highly porous limestone with the data published on testing of other limestones worldwide (Bednarik et al., 2014;Ghafoori et al., 2018;Ozguven and Ozcelik, 2013). It emphasises the importance of test conditions and the loss of strength due to water saturation (Vásárhelyi, 2005;Zenah et al., 2019). These are key issues since the stability of these subsurface openings strongly depend on the mechanical parameters of the host rock. ...
Four different porous limestone lithotypes were collected from the cellar system of Budapest (Hungary). All lithologies have high porosities ranging from 16 to 30%. The laboratory analyses focused on the mechanical properties testing to assess the strength changes due to water saturation. The density, ultrasonic sound wave propagation, uniaxial compressive strength (UCS) and indirect tensile strength (determined by Brazilian test) test were measured on cylindrical specimens according to EN and ASTM standards in the laboratory. Both dry and water-saturated samples were tested. The results indicate that four lithotypes have distinct strength parameters, and both the UCS and the indirect tensile strength decrease with water saturation. The largest decrease in strength was observed at fine-grained porous limestone and at fine- to medium-grained limestone with a decrease in strength of over 50%. On the contrary, the strength loss of coarse porous limestone is in the order of 16 to 14% of UCS and indirect tensile strength, respectively. Comparing the data set of this study with previous works on various limestones, a good correlation was found between density and Brazilian tensile strength. The presented data set was used as the input parameters for calculating the stability of dry and water inundated cellars. The FEM (Finite Element Methods) calculations of cellar stability indicate that the displacement of water-saturated cellars is nearly triple of the dry ones and that the factor of safety reduced from 1.74 in air-dry condition to 1.07 in water-saturated conditions.
