Among the programmes aimed at developing a standard model for properties and state of the Earth’s crystalline crust, those dealing with drilling the Kola (SG-3), Ural (SG-4) and German (KTB) superdeep boreholes yielded the most interesting results. No marked depth dependence of rock volume density and seismic wave velocities was observed in the sections of SG-3 and SG-4. A new result of the investigations is the discovery of strongly anisotropic rocks in the SG-3, SG-4 and KTB sections. In the massifs of the Kola and German superdeep boreholes such rocks constitute the majority of the drilled sections. The presence of the velocity anisotropy as well as the complex structure of the rocks composing crystalline metamorphosed sequences greatly hamper the interpretation of the results obtained from the seismic survey conducted at the surface., Felix F. Gobratsevich., and Obsahuje bibliografii
Preferential flow paths in the crust, as caused by the presence of the Luchlompolo fault in the drilled section of the Kola Superdeep Borehole (SG-3) and the dip angle of the rock structural elements (layering, schistosity, banding), are favourable for migration of deep fluids to the Earth’s surface. An investigation of the structure, anisotropy and permeability of rocks under PT-conditions in the SG-3 section, in addition to the occurrence of He-isotopes, reveals that the high-permeability zones of the exposed crustal segment are related to two important structural elements of the section: in the upper zone - to the Luchlompolo fault, in the lower one to the contact between the Proterozoic and Archaean complexes. The obtained results on the rock samples from SG-3 indicate a rough correlation between permeability and elastic anisotropy of various rock samples. Simulating increased PT-conditions, corresponding to the relevant depths of 6-8 km document the overlapping temperature and pressure effect, i.e. resulting in a sharp decrease of rock permeability., Felix F. Gorbatsevich, Serafim V. Ikorsky and Andrey V. Zharikov., and Obsahuje bibliografii
Geopolymers are one of the modern materials that can replace Portland cement. These materials are characterized by both high strength and high heat resistance. Foam geopolymers provide thermal protection. Foamed geopolymers with coke dust fill at 3 % relative to the base geopolymer (binder) and hollow corundum microspheres at 1 % and 3 % relative to the binder were examined. Compressive strength was found to be most affected by the addition of 3 % corundum hollow spheres. For flexural strength, this cannot be unequivocally demonstrated, as foamed geopolymers are themselves brittle and strengths with 5 % coke dust and 3 % corundum take place within statistical uncertainty. and Geopolymery jsou jedny z aktuálních materiálů, kterými je možno nahradit portlandský cement. Tyto materiály se vyznačují jak vysokou pevností, tak vysokou žárovou odolností. Tepelnou ochranu poskytují vypěněné geopolymery, které byly zkoumány s výplní z koksového prachu v množství 5 % vzhledem k základnímu geopolymeru (binderu) a dutých korundových mikrokuliček v množství 1 % a 3 % vzhledem k binderu. Bylo zjištěno, že pevnost v tlaku nejvíce ovlivňuje přidání 3 % korundových dutých kuliček. U pevnosti v ohybu toto nelze jednoznačně prokázat, protože vypěněné geopolymery jsou samy o sobě křehké a pevnosti s 5 % koksového prachu a 3 % korundu se odehrávají v rámci statistické nejistoty.