Geotechnical investigation and stabilization of the foundations of a World Heritage in Portugal, the Guimarães Castle

摘要

Conservation and restoration of monuments and historical areas are disciplines thatrnrequire specific training. The forts and castles are among these monuments that present high complexityrndue to the elevate nature of the forts. Each fort and castle has distinctive engineering and architecturalrnfeatures that turn its study a challenge. In this paper, the methodologies followed in the studies and investigationsrnon ancient forts carried out at University of Porto are briefly presented. Studies concerning fortsrnwith Portuguese legacy are presented. In particular, a specific study is presented focusing on the rehabilitationrnof foundations and walls of Guimarães castle in Portugal. Preliminary diagnosis of the castle wallsrnhas shown important pathologies in two walls, one of them located in the north tower where apparentrncracks and joint openings were clearly visible. In the latter, the cracking pattern was consistent with possiblernfoundation movements that were found likely to be responsible for wall corner rotation which inducedrnsigns of stones’ crushing in the wall base in contact with the foundation rock mass. An assessment ofrnthe causes of the appearance signs of holes or torn threads in the exposed face of the wall and tower ofrnthe extreme southwest of the castle was done, after the site survey with geotechnical laboratory tests. Thernintervention performed was focused both on the foundation and the walls, starting by the foundation stabilizationrnby nailing a set of high-strength blocks of rock mass and careful sealing of the massive networkrnof high strength and consolidation of the most altered and fractured. Subsequently, the wall cracks andrnjoint openings should be repaired, but structural monitoring was started beforehand in order to controlrnany possible movements both during the geotechnical works and for a three year long period after repairingrncracks and joints. Construction issues including logistics and problems found are described, as well asrnthe main outcome of the monitoring process and the finally adopted structural interventions.