Browsing by Subject "dynamic loads"

Now showing 1 - 3 of 3

Access status: Open Access ,
A contribution to the design of powered roof support for operations in a rockburst-hazardous environment
(Wydawnictwa AGH, 2020) Świątek, Janina; Stoiński, Kazimierz; Styrylski, Konrad
The paper presents an example of a numerical analysis using ANSYS to optimise the design of powered roof support designed to operate in rock mass tremor hazard conditions. The areas of excessive stress in the structure of powered roof support were identified, taking into account the increase in rock mass loading resulting from tremors. An increase in the load impacting on the support as a result of rock mass tremors is the cause of excessive stresses in the section structure. The paper aims to identify them and to find ways to apply the design using numerical analysis. The analysis was conducted for roof support type ZRP-15/35-POz produced in Repair and Production Plant (ZRP-Bieruń) of Polish Mining Group S.A. (PGG S.A.) The introduction of reinforcements in places of increased stress in the support section structure should increase its operational safety in the excavation.
Access status: Open Access ,
Ocena zagrożenia tąpaniami w kopalniach podziemnych uwzględniająca parametry drgań blisko ognisk wstrząsów - doświadczenia z polskich kopalń
(2007) Mutke, Grzegorz
To study the rockburst hazard and underground mine working stability it is essential to know not only the static loads but also the dynamic loads. The performed analysis of the effects of mine tremors from the Upper Silesian Coal Basin, and of their intensity and various types of damage, clearly shows that they only occurred when the tremor sources were located close to the openings (mostly up to 100 m). These observations show that the ground motions parameters at such distances may be crucial for the occurrence of a rockburst because the high values of the PPV parameter are proportional to high dynamic stresses and underground hazards. An empirical criterion for potential rockburst hazard has been developed based on the worked out correlation dependences. In analyzing the documented database of 120 rockbursts from the Upper Silesian Coal Basin that occurred during a period from 1988 to 2006, the above mentioned criterion was verified. It has been found, that 90% of the rockbursts occurred in the area where peak particle velocity (PPV) reached values ranging from 0,05 m/s to 1 m/s. The investigation results presented in this this paper may be used in both the spatial and time table planning of mining operations under predicted high seismicity conditions and the rational choice of support and preventive actions ensuring functionality of mine workings and improvement in work safety level.
Access status: Open Access ,
Stanowiskowe badania elementów obudów górniczych przy ich dynamicznym obciążeniu
(2007) Pacześniowski, Krzysztof; Pytlik, Andrzej; Radwańska, Ewa
This paper presents results of stand tests of elements of mine supports with increased resistance to dynamic loads. The increased resistance of the mine supports subjected to the tests is a result of improved work on the hitherto designs of supports. The application of the increased supports results in increasing safety on longwalls and mine roads in the areas with ground tremor hazard. This paper shows dynamic characteristics of reaction of the mine support elements the resistance of which to dynamic loads has been improved as compared to the hitherto constructive solutions. Also the stand used for testing elements of mine supports under dynamic loads is described. The technical possibilities of the stand as well as the measurement and recording instruments used during the test are presented.