DEVELOPMENT OF SOIL DISPLACEMENT AND STRAIN GAGES
Abstract
For evaluation of the effects of nuclear or chemical explosions, the horizontal and vertical transient displacements of the ground nearby or of certain structural elements need to be measured. Integration of accelerometer or velocity gage records is unsatisfactory for many purposes, and direct displacement measurement is desired. Similarly, improved devices for measuring earth strain from large explosions are desired. Of the several displacement gages considered, the design consisting of a geared compound pendulum was found optimum for most applications. This design was first used and tested as an aperiodic gage with considerable success, but it had operational drawbacks. These have been eliminated by changing to a long-period undamped periodic gage, at the cost of greater departure from direct proportionality between output and displacement. Numerical means for correcting gage records for gage characteristics have been devised, resulting in greater accuracy over longer periods than was practically feasible with the aperiodic gages. It was concluded that earth strain gages at depth should be grouted in place in relatively small holes, using a grout no less compliant than the formation. A strain gage was devised which is particularly adapted for installation on a wire line associated with other instruments. Means for avoiding errors caused by the presence of the wire line were devised. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1961
- Accession Number
- AD0282685
Entities
People
- L.m. Swift
Organizations
- SRI International