The use of foil type strain gages on geosynthetics is poorly documented. In addition, very few individuals are versed in proper installation techniques or calibration methods. Due to the limited number of knowledgeable technicians there is no information regarding the susceptibility of these gages to errors in installation by inexperienced installers. Also lacking in the documentation related to the use of foil type strain gages on geosynthetics is the survivability of the gages in field conditions. This research documented procedures for installation, calibration, and survivability used by the project team to instruments a full scale field installation in Marked Tree, AR. This research also addressed sensitivity to installation errors on both geotextile and geogrid.

To document the process of gage installation an experienced technician, Mr. Joe Ables, formerly og the UASCE Waterways Experiment Station, was consulted. Hs techniques were combined with those discovered in related literature and those developed by the research team to develop processes that were adaptable to multiple gage geometries and parent geosynthetics. These processes were described and documented in a step by step manner with accompanying photographs, which should allow virtually anyone with basic electronics knowledge to install these gages properly.

Calibration of the various geosynthetic / strain gage combinations was completed using wide width tensile testing on multiple samples of each materials. The tensile testing process was documented and analyzed using digital photography to analyze strain on the strain gage itself. Calibration factors for each geosynthetics used in the full scale field testing were developed. In addition, the process was thoroughly documented to allow future researchers to calibrate additional strain gage and geosynthetic combinations.

The sensitivity of the strain gages to installation errors was analyzed using wide width tensile testing and digital photography to determine the variability of the data collected from gages with noticeable installation errors as compared to properly installed gages. Induced errors varied based on the parent geosynthetics materials, but included excessive and minimal waterproofing, gage rotation, gage shift, excessive and minimal adhesive, and excessive and minimal adhesive impregnation loads. The results of this work indicated that minor errors in geotextile gage installaton that are noticeable and preventable by the experienced installer have no statistical significance on the data recorded during the life span of the geotextile gages; however the lifespan of the gage may be noticeable shortened by such errors. Geogrid gage installation errors were found to cause statistically significant changes in the data recorded from improper installations.

The issue of gage survivability was analyzed using small scale test sections instrumented and loaded similarity to field conditions anticipated during traditional roadway construction. Five methods of protection were tested for both geotextile and geogrid including sand blanket, inversion, semi-hemispherical PCV sections, neopene mats, and geosynthetic wick drains were selected to protect geogrid installed gages. These methods resulted in survivability rates of 73% and 100% in the full scale installation respectively. (Kode: UMI Number: 1478477) Rak Penelitian 2

This research and documentation may be used to train technicians to install and calibrate geosynthetic mounted foil type strain gages. In addition, technician should be able to install gages in the field with a high probability of gage survivability using the protection methods recommended.