第9章-Environmental effects and safety of blasting.ppt

9 Environmental effects and  safety control of blasting 9.1 Introduction 9.2 Fly-rock 9.2.1 Causes and alleviation 9.2.2 Protective measures 9.3 Ground vibrations 9.3.1 Causes 9.3.2 Estimation equation 9.3.3 Reducing ground vibrations 9.4 BLASTING SAFETY 9.1 Introduction There are four environmental effects of blasting in general:? 1)? Fly-rock 2)? Ground vibrations 3)? Air-blast and noises 4) Dust and gases Fly-rock is a potential cause of death, serious injury, and property damage. Ground vibrations and air-blast are potential causes of property damage and human annoyance, but are very unlikely to cause personal injury. Fly-rock, ground vibrations, and air-blast all represent wasted explosive energy. Excessive amounts of these undesirable side effects are caused by improper blast design or lack of attention to geology. When excessive side effects occur, part of the explosive energy that was intended to give the proper amount of rock fragmentation and displacement is lost to the surrounding rock and atmosphere. Serious dust or gas problems are sometimes caused by blasting. Pre-blast survey When blasting in vicinity of structures such as homes, hospitals, schools, and churches, a pre-blast survey, documenting the condition of the structures, is often beneficial. A pre-blast survey has a twofold purpose. First, it increases communications between the community and the blast operator. Good public relations are the operator’s best means of reducing blasting complaints. A pre-blast survey helps the operator to maintain good community relations. Pre-blasting surveys have been found to be an excellent investment. The second purpose of a pre-blast survey is to provide a baseline record of the condition of a structure against which the effects of blasting can be assessed. When combined with a post-blast survey, this will help assure equitable resolution of bl