Tymoteusz Zydroń

IMPACT OF A TEST METHOD ON THE UNDRAINED SHEAR STRENGTH OF A CHOSEN FLY ASH

The paper presents an assessment of the suitability of a laboratory vane apparatus, a cone penetrometer as well as a shear vane tester and a pocket penetrometer for determination of the parameters of the undrained shear strength of fly ash from the Power Plant “Skawina”. The suitability of the cone penetrometer and the laboratory vane apparatus for the determination of the undrained shear strength of the fly ash has been shown. On the bases of the obtained test results, , drained and undrained shear strengths of the subsoil made of the fly ash under the square pad foundation were calculated according to Eurocode 7. The calculations of the ultimate resistance of the drained subsoil showed that it was several times bigger than its value in undrained conditions. This confirms the need for the proper determination of the angle of internal friction and cohesion as well as the undrained shear strength of fly ashes.

Analysis of rainfall-induced shallow landslides in Jamne and Jaszcze stream valleys (Polish Carpathians) – preliminary results

Abstract Analysis of rainfall-induced shallow landslides in Jamne and Jaszcze stream valleys (Polish Carpathians) - preliminary results. Preliminary shallow landslide susceptibility mapping of the Jamne and Jaszcze stream valleys, located in the Polish Flysch Carpathians, is presented in the paper. For the purpose of mapping, there were used SINMAP and Iverson’s models integrating infiltration and slope stability calculations. The calibration of the used models parameters, obtained from limited field and laboratory tests, was performed using data from 8-9 July 1997, when as a consequence of a very intense rainfall, 94 shallow landslides were observed on meadows and arable lands. A comparison of the slope stability calculation results and the localisation of the noticed shallow landslides showed satisfactory agreement between localisation of the observed and computed unstable areas. However, it was concluded that better simulation results were obtained using Iverson’s model.

Shear strength of clayey soils from the vicinity of Gorlice and Ciężkowice

Abstract The work presents results of maximum and residual strength tests of six clayey soils from the landslide areas near Gorlice and Ciężkowice. The tests were carried out in a direct shear apparatus on samples of dimensions 60 × 60 mm that were sheared at least three times. A shearing strain rate was equal 0.1 mm·min–1, and the range of horizontal deformation of the samples was equal 20%. The results of the tests revealed that multiple shearing of the soil caused a significant decrease of its shear strength, resulting in significant changes in cohesion, and the smaller changes in the angle of internal friction. It was shown that the three-time shearing reduced the initial shear strength of about 50%, and further three series of shearing decreased it approximately 15% more. The study also showed that by using a Coulomb-Mohr shear strength linear equation, the analyzed soils had a little residual cohesion. Therefore, to describe the characteristics of the residual strength, there were used two non-linear equations proposed by Mesri and Shanien (2003) and Lade (2010), which led to the same results. It was also shown that the use of non-linear characteristics of the residual strength at low values of the normal stresses gave more unfavourable results of stability calculations in relation to the method based on the linear strength characteristic taking into consideration the presence of the residual cohesion.

Impact of meteorological conditions on stability of selected slopes in the Wiśnicz Foothills

Abstract Impact of meteorological conditions on stability of selected slopes in the Wiśnicz Foothills. Mass wasting is one of the most important processes influencing the shaping of mountain slopes. Most programs for testing mass wasting are limited to short-time, single observations, and to surface measurements of the big phenomenon ignoring shallow landslides occur resulting in slope covers, or on its border with the rock solid. That is why, when analyzing the causes of mass wasting processes, it is extremely important to assess the influence of meteorological conditions on water circulation in the landslide slope system and the status of stresses in a soil medium that is connected with it. The aim of this work was to determine the course of changes in stability conditions for two selected slopes, connected with meteorological conditions in the period of 2009-2013 on the area of the Wiśnicz Foothills. Numerical analysis were subjected to two slopes in villages the Królówka and the Łychów. Meteorological data for analysis, i.e. air temperature and soil humidity, wind speed, precipitation sum and length, were taken from the station Jagiellonian University in Łazy. To determine the course of changes of stability factor used capabilities Geostudio 2007 (Slope/W, Vadose/W, Seep/W). The work is a pre-development servant indicate the formation of shallow landslides present in silt. Results of the stability calculations confirmed the common opinions that conditions of slope balance are very strongly connected with atmospheric precipitation, but it was also shown that they also depend significantly on thermal conditions. These calculations showed that in the period 2009-2013 the most unfavorable conditions of stability were obtained in May 2010, which is a confirmation of the situation observed in reality. Streszczenie Wpływ warunków meteorologicznych na kształtowanie się warunków stateczności wybranych zboczy Pogórza Wiśnickiego. Jednym z najważniejszych procesów wpływających na kształtowanie stoków górskich zbudowanych z fl iszu karpackiego są ruchy masowe. Tylko na nielicznych obiektach prowadzono kompleksowe, pogłębione badania mechanizmów inicjacji ruchów osuwiskowych. Badania takowe są czasochłonne, a zadowalające i wiarygodne wyniki osiąga się po co najmniej kilkuletnim okresie pomiarów i analiz. Większość programów badań ogranicza się do krótkich, jednorazowych obserwacji i pomiarów powierzchniowych. Uwaga uczestników tych projektów skupia się na dużych osuwiskach strukturalnych obejmujących swoim zasięgiem głęboko zalegające skały trzeciorzędowe, pomijając płytkie osuwiska zachodzące na granicy zwietrzeliny i skał litych oraz w zasięgu samej zwietrzeliny. Celem pracy było określenie przebiegu zmian warunków stateczności wybranych zboczy związanych ze warunkami meteorologicznych występujących w latach 2008-2013 na obszarze Pogórza Wiśnickiego. Dla potrzeb pracy wykorzystano dane meteorologiczne, tj. temperatura powietrza, wilgotność gleby, prędkość wiatru, sumy opadów i liczba dni z deszczem, pochodzące ze Stacji Naukowej IGiGP UJ w Łazach koło Bochni (Pogórze Wiśnickie). Przeprowadzono terenowe i laboratoryjne badania parametrów geotechnicznych gruntów stanowiących pokrywy stokowe wybranych zboczy osuwiskowych we wsiach Królówka i Łychówo. Wcześniej wspomiane dane meteorologiczne, a także dane dotyczące temperatury, wilgotności względnej powietrza wykorzystano w dalszej części pracy do określenia zmian stanu naprężeń dla dwóch zboczy osuwiskowych. W tym celu zastosowano moduły Slope/W, Vados/W oraz Seep/W stanowiące część pakietu GeoSlope. Wyniki analiz potwierdziły, że stabilność zbocza jest silnie związana z opadami atmosferycznymi, ale wykazały również jej istotną zależność od warunków termicznych. Przeprowadzone obliczenia z lat 2009-2013 wykazały, że najbardziej niekorzystne dla zachowania statyki zbocza warunki wystąpiły w maju 2010 roku, co jest potwierdzeniem obserwacji terenowych.