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Thermo-mechanical coupled damage behavior of pre-damaged rock sculptures and monuments - laboratory experiments and numerical simulations: Thermo-mechanical coupled damage behavior of pre-damaged rock sculptures and monuments - laboratory experiments and numerical simulations

Cotttaer sandstone is a quite popular material used for sculptures and monuments for almost 1,000 years. Such sculptures and monuments will be damaged after several years. The reasons for that could be different: mechanical damage due to carving by sculptors, expansion stresses due to salt crystallization or temperature change. Damages also happen sometimes after inappropriate consolidation.
Cottaer sandstone before and after consolidation was investigated by lab testing and numerical simulations in this thesis. The aim is to develop a simulation strategy which can simulate the thermomechanical coupled damage behavior at grain size level. The main research works of this thesis are as follows:
*Uniaxial compression tests, Brazilian tension tests and size effect tests were carried out to investigate the mechanical parameters of original Cottaer sandstone.
*Ultrasonic wave velocity measurement and special biaxial flexural tests were carried out to determine how deep the consolidation material penetrates and how much strength of sandstones is increased by using two different injection materials.
*A Voronoi-based numerical simulation strategy was developed which considers grain size, grain shape and pore size. Mineral components, intra- and inter-granular contacts and intra- and inter-granular fracturing were considered as well.
*Uniaxial compression tests and Brazilian tension tests of unconsolidated sandstone were simulated. This simulation strategy can capture inter- and intra-granular fracturing.
*Prediction of thermo-mechanical coupled behavior of consolidated and unconsolidated sandstone samples was performed. The simulation results show that thermal properties of grains and filled pores have influence on temperature distribution and fracture development in the sandstone. Also, thermal induced displacements are strongly influenced by boundary condition.

Identiferoai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:23163
Date13 September 2017
CreatorsLi, Jun
ContributorsKonietzky, Heinz, Blum, Philipp, Yang, Shengqi, Technischen Universität Bergakademie Freiberg
Source SetsHochschulschriftenserver (HSSS) der SLUB Dresden
LanguageEnglish
Detected LanguageEnglish
Typedoc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text
Rightsinfo:eu-repo/semantics/openAccess

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