![]() Dans ce contexte, une évaluation précise du risque chutes de blocs est devenue cruciale pour les gestionnaires et les pouvoirs publics. Cet aléa cause chaque année de nombreux dommages aux biens ou aux personnes. L’aléa chute de bloc est lié au détachement d’un bloc rocheux depuis une paroi verticale ou sub-verticale, qui se propage rapidement vers l’aval sous l’effet de la gravité par rebonds successifs. From a practical point of view, and despite epistemic uncertainties related to the rockfall magnitude/frequency relation, the parameterization of the trajectory model and the absence of a site-specific vulnerability curve, this study clearly demonstrates the value of QRA as a reproducible and objective method for risk zoning and risk management. On a spatial plan, these results make it possible to identify the areas most prone to risk and show that a large proportion of the total risk is concentrated on a few buildings located in the Le Coteau neighborhood. The results, expressed as the mean surface destroyed per year, demonstrate (i) the protective effect of the forest stand for block volumes up to 7 m³, and (ii) the surprisingly high proportion of total risk due to intermediate volume classes (7–12 m³). Here, the risk for buildings is calculated at the scale of the municipality of Crolles (southeastern slopes of the Chartreuse Mountains, French Alps), by considering a wide range of volumes (1–20 m³) and the 300-m-high sub-vertical cliff overhanging the village. Given the importance of characterizing the risk in an objective and reproducible manner, this study proposes a quantitative risk analysis (QRA) procedure accounting for the specificities of the rockfall process. In this context, a precise rockfall risk analysis has become essential for authorities and stakeholders. Every year, some rockfalls reach urbanized areas, causing damage to structures and injuring people. This name originated from the fact that large quantities of rock loosened by some of the larger rock bursts displaced quantities of air, with the result that a blast of air passed through the mine workings.The rockfall phenomenon is defined as a rock block that detaches from a vertical or sub-vertical cliff and travels down the slope in rapid motions. 4, record 1, English, - rock%20burst Record number: 1, Textual support number: 2 OBSįor "air blast" : In former years rock bursts were sometimes referred to as "air blasts". A large proportion of these "bumps" or "bounces" are actually "coal bursts" due to fracturing of pillars and remnants and need not involve any fracturing of roof or floor rock. 8, record 1, English, - rock%20burst Record number: 1, Textual support number: 1 OBSįor "coal burst" : Rock bursts and "coal bursts" in coal mines are generally designated by the term "bumps" or "bounces". Frequently, a large volume of gas(usually methane) is suddenly released during a rock burst in a coal mine. Where the coal or the associated rocks are particularly strong and depths are much above average, these stresses may be relieved by rock bursts, which are relatively violent outbursts of the coal into the rooms and entries. If the coal pillars, the roof, or the floor are able to yield gradually, the effects of the stresses are relieved by floor heaving, or by pillar or roof failure. In areas of very deep mining, as additional weight is supported by the pillars on the coal face, stresses may so build up that the yield point is reached. 7, record 1, English, - rock%20burst Record number: 1, Textual support number: 1 CONT ![]() The sudden failure of walls or pillars in a mine caused by the weight or pressure of the surrounding rocks, and accompanied by a violent release of energy. Record number: 1, Textual support number: 1 DEF
0 Comments
Leave a Reply. |