Nuevo método de inspección no destructivo con radar de penetración terrestre para evaluar la idoneidad de la inyección de mortero de relleno en tuneladoras

Abstract

This research focuses on the development of a new non

destructive inspection method, based on the interpretation

of electromagnetic waves by means of a ground penetrating

radar (GPR), to evaluate the condition of the backfilling

two-component mortar grouting behind the segmental

lining in tunnels made by tunnel boring machines (TBM). The

data processing by digital models and the analysis of the

propagation speed of the along the backfilling grouting layer

have enabled the technical and operational feasibility of this

novel inspection method.

Once the conceptual framework of the research was defined,

it was possible to validate the developed method in a full

scale operational environment in the Metro of Quito Line 1

(Ecuador). This validation involved a battery of tests collating

the results obtained through the core-drilling extractions in

comparison with the ones obtained with GPR. As a result of

these calibration tests, it was possible to identify a range of

propagation speeds linked to grouting in optimal execution

conditions, as well as other ranges associated with potential

anomalies. Finally, it was possible to implement this new

inspection methodology on a regular basis in the Metro of

Quito, where the conventional quality control by core-drillings

was replaced almost entirely for the new method with GPR.