Assessment of the Structural Effects of Blasting by the Analysis of Motion Measurements

摘要

Structures close to a blast respond to the motion of the ground as the ground vibration passes. The response of structures depends on many factors including: (1) The Peak Particle Velocity (PPV) and frequency spectrum of the ground vibration; (2) The natural frequency and damping characteristics of the structure; (3) The shape, nature and physical dimensions of the structure; (4) The exposure time of the structure to the ground motion. As the structure flexes in response to the ground motion, strains are induced in the structure. Strains of sufficient magnitude will result in damage of varying degrees. This paper describes the methodology developed by Terrock to predict the maximum strains induced in any structure from ground PPV measurements. The methodology was developed from measurements of the motion at different points on a range of structures and comparing the predicted strains from Plane Wave Strain Theory with direct strain measurements on the structure itself. A ground PPV limit to prevent damage can then be ascertained when the induced strains are compared to allowable working strains from appropriate design codes and Serviceability Standards for the building material and structural elements involved.