A New Method for Monitoring Geogrid Deformation Based on OFDR Technology

ABSTRACT Geogrid is widely used in slope, retaining wall, embankment, and other projects as the new geosynthetic material. In order to master the deformation behavior of geogrid, this study employs advanced optical frequency domain reflectometry (OFDR) technology to capture the deformation of geogrid; the optical fiber sensor installation method is considered; the influence of colloidal layer on strain transmission is explored; the medium type around the geogrid is changed; and the deformation characteristics of geogrid during the pulling process are analyzed. The results reveal that the strain of slotted layout is larger compared with tie layout, and the deformation trends of the two layouts are the same. The colloidal layer demonstrates an excellent strain transfer efficiency, with a coefficient of 97 %. The geogrid pulling test successfully measures the deformation of geogrid in both sand and air medium using OFDR technology. The strain of the geogrid in sand medium is small; it indicates that the surrounding medium effectively restrains the deformation of geogrid.