Preliminary results of GPR field prospection carried out in the area of the prehistoric mining field Borownia (Ćmielów, Ostrowiec Świętokrzyski District) are presented. This mining field forms a belt (30-50 m wide and 700 m long), starting from the valley edge of the Kamienna River southeastwards. Southeastern and western parts of the site have preserved the original post-exploitation relief. Geology of the Borownia mining field was examined and acquired radiograms revealed three distinct zones of anomaly concentrations. The central zone (B) is clearly a fragment of the prehistoric mining field, confirmed not only by the GPR sounding but also by archeological surveys. The other two zones have not yet been investigated in detail yet but their surface and archaeological examination may determine only whether their underground structures are natural or have been created by humans. Data obtained during the GPR prospection at the Borownia archaeological site confirmed usefulness of 100, 250 and 500 MHz antennas. The relatively large depth range and good resolution are due to favorable geological conditions.

This pa per pres ents the test re sults of hor i zon tal hy drau lic con duc tiv ity (k) of fen peats from east ern Po land. Three fen peatlands in the Lubartów Pla teau (3 ob jects marked as LP1, LP2 and LP3) and two in the Siedlce Pla teau (2 ob jects marked as SP1 and SP2) have been se lected. The ob jects rep re sent a val ley bog type and are sim i lar in peat thick ness, but dif fer ent in area size. They also vary in terms of bo tanic com po si tions and ba sic phys i cal and chem i cal pa ram e ters of peats. BAT permeameter was used for in situ mea sure ments of hor i zon tal hy drau lic con duc tiv ity. Hor i zon tal hy drau lic con duc tiv ity of the peats var ies from 1.3 ´ 10 -8 to 1.1 ´ 10 -6 m/s. The low est val ues of hor i zon tal hy drau lic con duc tiv ity were ob served for silted (high-ash) car bon ate peats and amor phous or pseudo-fi brous peats, while the high est val ues were ob served for unsilted (low-ash) non-car bon ate peats of fi brous struc ture. The anal y sis of vari abil ity of hor i zon tal hy drau lic con duc tiv ity showed that the low est val ues were ob served in each case for the bot tom of the stud ied pro file. The study al lowed to in di cate the specific ar eas within the peatlands dif fer ing in per me abil ity, and iden tify the role of in di vid ual ob jects as nat u ral geo log i cal bar riers.Key words: hy drau lic con duc tiv ity, nat u ral geo log i cal bar ri ers, peat, val ley bog.

This paper addresses the problem of assessing the leakproofness of the bottom of a deep foundation trench, secured by cavity wall, using geophysical methods of electrical resistivity tomography. The study was conducted on a large construction project in Lublin, in a place where there are complicated soil-water conditions: the groundwater level is above the proposed depth of foundation trench, the subsoil is heterogeneous, and there are karsted and weathered carbonate sediments with confined aquifer below the bottom of the trench. A hydraulic fracture occurred at the bottom of the trench during the engineering works, which caused the water flow into the trench. In order to recognize the soil-water conditions the first stage of geophysical measurements of electrical resistivity tomography (ERT) was made. The applied methodology allowed to determine the extent of the hydraulic fracture zone within the bottom of foundation trench. In order to assess the leakproofness of Diaphragm Wall the geophysical ERT measurements were repeated (stage 2) A clear reduction in the value of the electrical resistivity of soils in the area of hydraulic fracture was caused by clay injection. The results of ERT measurements are discussed and graphically presented.

wrzykraj, P. 2016. Stress-strain behaviour analysis of Middle Polish glacial tills from Warsaw (Poland) based on the interpretation of advanced field and laboratory tests. Acta Geologica Polonica, 66 (3), 561-585. Warszawa.The selected parameters of the Wartanian and Odranian tills, with relation to their spatial occurrence, grain size distribution, mineralogical composition, matric suction and other physical characteristics, are presented. The assessment of the lithogenesis and stress history on the microstructure is attempted. The comparison of the compression and permeability characteristics from field and laboratory tests has been performed. Laboratory consolidation tests carried out with up to 20MPa vertical stress, revealed two yield stress values, one in the range of a couple hundreds kPa, the other in the range of a couple thousands kPa. Based on those results, the reliability of the soil preconsolidation assessment, with the use of the two different methods is discussed. The aspect of the triaxial strength reduction under the dynamic loading of diverse frequency and amplitude is raised. The research results depict a variety of possible geological-engineering characteristics, under the divergent constraints scenarios, of compression or strength weakening origin. The effects of the specialized research program will widen the possibilities of physio-mechanical and structural characterization of soils for geological-engineering purposes.

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