Vliv klimatickych pomeru na stabilitu vychozu paleozoickych hornin Landeku

Climatic conditions (in a sense of Rybář in Ondrášik - Rybář 1991) obviously play an important role as a geodynamic permanent or episodic element of factor (cf. Pašek et al. 1995) effecting the integrity and stability of a rock massif. Permanent or prolonged factors result in gradually cumulative phenomena which may later activate slope movements, whereas the episodic factors act quickly, thus causing sudden slope movements. In the case of the Landek Paleozoic rock massif, the local rock movement is represented by a rockfall type resulting in toppling, falling and sliding in terms of slope movements classification introduced by Nemčok et al. (1974).
The outcrops of Landek were declared a National Nature Monument, and their accessibility has been improved in 2012, due to the construction of a bicycle path that runs along their south-eastern foot. In August 2013 however, the path was closed due to an obstruction caused by rockfall. This event raised a question of how to protect the bicycle path, keep it passable, and avoid any danger. The City of Ostrava commissioned some companies to employ relevant remediation techniques (Skopal - Ryšávka 2013; Skopal - Ptáček 2015) in order to make the path safe. The suggested conventional remediation methods, such as surface stabilization using anchored wire mesh, or other technical elements turned out to be inconvenient due to their degrading these significant and spectacular outcrops. As the weather conditions might have played an important role in the local rockfalls, available meteorological data and records regarding the rockfall events, from the Czech Hydrometeorological Institute (the Ostrava-Poruba branch) were analyzed and interpreted. Consequently, judging from meteorological records the varying climatic conditions are likely to have triggered local rock falling (episodic factor).
To mechanical strain of massif by climatic condition occurs mainly during the fluctuations temperature around 0 °C (freezing - thawing), by intense water saturation during long-lasting rains or during suddenly short-lasting storm activity and in high summer temperatures (tropical days > 30 °C).
Subsequently, the Economic Development Department of the City of Ostrava, in cooperation with the Czech Geological Survey, was made an information board to notify visitors about the possibility of rock falls, and when it is safe or risky to enter the bicycle path with regard to climatic conditions (Malík 2014). In order to increase safety of the path, concrete barriers were installed in selected sections along the outcrops as a temporary protection barrier, which are unattractive from an aesthetic point of view but make passing safe.