Geosynthetic strain gage installation procedures and alternative strain measurement methods for roadway applications

摘要

ABSTRACT: The measurement of geosynthetic strain is important to the development of numericalnmodels that can predict the behavior of geosynthetic-reinforced flexible pavements. This papernoutlines the key issues regarding foil strain gage selection, installation, and calibration onngeosynthetics for dynamic strain measurement in roadway applications. The flexible nature ofngeosynthetics and the interaction of these materials with the adjacent layers of the pavementnstructure in a dynamic loading application limit the ability to use all types of strain gages andnadhesives. While this paper does not cover every type of geosynthetic, it provides sufficientnprocedural details and illustrations of foil strain gage installations on a variety of geosyntheticsn(woven geotextiles and geogrids, nonwoven geotextiles and punch/drawn geogrids) and then outlinesnseveral alternative methods (wire extensometers, inductance coils and fiber optics) of dynamicnstrain measurement. While foil strain gages and closely spaced wire extensometers provide anlocalized value of displacement on a geosynthetic, wire extensometers and inductance coils providena measure of global displacement (which includes slack in the geosynthetic) and redundancy inntotal strain measurements. Fiber optics is an emerging and very promising method of accuratelynmeasuring strain in geosynthetics, and at least one delivery system has been developed.