Evaluation of the risk associated with karstic processes in Miocene gypsum in south-eastern Madrid (Spain)

Abstract

IzvlečekUDK 551.435.8:552.5 (460Madrid)"628.42" Félix Escolano Sánchez, Alberto Mazariegos de la Serna & José María del Campo Yagüe: Ocena tveganj povezanih z zakrasevanjem miocenske sadre v jugovzhodnem Madridu (Španija) V jugovzhodnem Madridu je veliko reliefnih oblik, ki kažejo na zakrasevanje miocenske sadre. To predstavlja tveganje, ki ga moramo upoštevati pri urbanističnem načrtovanju. V članku predstavljamo celovit pristop, ki temelji na geomorfoloških analizah aeroposnetkov, mikrogravimetričnih in geotehničnih raziskavah, s katerim smo zaznali in izmerili morfološke značilnosti, ki so povezane z aktivnim zakrasevanjem sadre. Analiza tveganj temelji na študiji dejavnikov tveganja in se osredotoča na ranljivost in oceno uspešnosti strukturnih ukrepov za blažitev vpliva zakrasevanja v prsti na strukturne temelje. Ključne besede: Sadra, kraški procesi, dejavniki tveganja, strukturni blažilni ukrepi. Relief formations characteristic of karstification processes affecting the Miocene gypsum formations existing in south-eastern Madrid have been discovered in that area of the city. These relief formations can pose significant risks to future urban development plans. The purpose of this article is to present an integrated model created from a geomorphological analysis of south-eastern Madrid through aerial photographs, geophysical inspections (microgravimetry) and geotechnical studies (in situ drilling and testing), in order to identify and measure the morphologies associated with karstic processes whose locations, dimensions and geotechnical characteristics are prone to causing damages that could pose a potential risk. The risk analysis is based on a study of the risk factors, focusing on vulnerability and the measurement of structural mitigation measures capable of preventing the damages that could be caused by the interaction between structural foundations and the morphological consequences of karstic processes on the soil.

Strategies on Reuse of Clayey Expansive Soils as Embankment Material in Urban Development Areas: A Case Study in New Urbanized Zones

“…Finally, a methodology is established in order to contribute to the improvement and development of new techniques that have been proven valid for this type of land, and, the future fields of application are described. The growing demand for urban land in the city of Madrid in recent years has made it necessary to use geotechnically problematic areas which have historically been avoided [1][2][3]. Without any doubt, the lands in the southeast of Madrid are the most relevant in this aspect, not only because they are the new and future areas of expansion of the capital city of Spain, but also because they pose a barrier to the social and economic growth of the city due to their clayey and potentially expansive nature [4].…”

“…One of the most representative characteristics of these types of deposits is the density. They are materials with a very low density and a range of values of between 0.76 and 1.68 g/cm 3 with an average value of 1.24 g/cm 3 , due to the presence of sepiolite and saponite materials. The natural humidity of all the analyzed samples shows values ranging between 18.4% and 70.5%, with an average value of 34.1%.…”

Chemical Injections Realized with Null Pressure for Underpinning the Foundation of an 18th Century Building Located in the Historical City of Cuenca (Spain)

“…When this initial lifting is observed, it means that the consolidating action is being directed vertically upward and that this is the direction that offers the least resistance, while the surrounding soil offers greater resistance in respect of the decrease in the structural load, which means that the foundation soil has been compacted enough to withstand not only the increase in static loads, but also the loads created by the lifting [5,6].…”

“…The density of the liquid mixture is equal to 1070 kg/m 3 , very close to that of water. Under these conditions, the expanding volume is equal to 30 times the original volume of the mixture [5,6].…”

Influence of Natural Cavities on the Design of Shallow Foundations

“…This is a relatively frequent problem worldwide, given the vast areas where these types of rocks appear. In the history of construction, there are many examples of failures of this nature, and the issue is the subject of periodic meetings of experts [1] and of studies evaluating their risk [2]. In Spain, these three types of rock masses are all present, with the surfaces occupied by limestones and dolomites covering 30% of the territory each, while 12% is occupied by evaporitic rocks [3].…”