Centrifugal and Numerical Modeling of Buried Structures. Volume 3. A Centrifuge Study of the Behavior of Buried Conduits Under Airblast Loads

摘要

The principle object of the research was to provide a better understanding of the behavior of the soil-structure interaction phenomena associated with buried conduits subjected to airblast loads. A parametric study was performed to experimentally determine the effects of airblast loads on 4-in diameter micro-concrete pipes, embedded horizontally in a dry sand. The parameters varied in the study included the gravity level, the applied airblast pressure level, the relative density of the dry sand, burial depth of the structure, and the relative stiffness between the structure and the soil. A geotechnical centrifuge was used to create the proper in-situ stress conditions in the sample during each test. Dynamic stress gages were utilized to measure the applied airblast on the sample surface, the normal stresses acting at the soil-pipe interface, and in the free-field conditions. Proximitors positioned inside of the structures were used to measure the resulting deflections. The results of the experimental study verified the importance of testing models at increased gravity levels, and determined the feasibility of the dynamic stress gages for measurement of contact and free-field stresses. Interesting trends in contact stresses around the circumference of the pipe; variations of 20 percent in relative density of the sand produced no significant changes in contact stress levels.