Abstract
Centrifugal model tests, which can reproduce the deformation process of the slope, play a crucial role in investigating the mechanism of slope failure. The FBG-based sensors, with high precision, electromagnetic resistance, light weight and small size, have been introduced into geotechnical centrifuge monitoring. The slope evolution is a complex multi-parameter dynamic process which involves the interaction of displacement, stress and strain. However, current research is mainly focused on one or two monitoring aspects, i.e., strain or displacement monitoring to study some specific questions. To achieve multi-parameter and real-time monitoring, a comprehensive fiber Bragg grating (FBG) monitoring system including miniaturized anchors, earth pressure gauges, inclinometer pipe and retaining wall, has been designed for geotechnical centrifuge tests. Before the centrifugal test, laboratory calibrations of sensors were carried out. The calibration results indicate that the FBG-based sensors can monitor the strain, stress and displacement variation precisely. The multi-parameter information related to slope stability were captured and analyzed in detail. The stress state of the anchors, strain distribution of retaining wall together with the displacement of the inclinometer pipe indicate the progressive evolutionary process of the model slope. The test results also indicate that the critical centrifugal force for the transition of the sliding surface is 45 g, after which, a sliding surface is formed in the soil above the retaining wall. The feasibility and validity of the monitoring system is verified by a comparison between the results of FBG-based sensors and those of a numerical simulation. In summary, the innovative FBG-based monitoring system has provided a feasible multi-parameter monitoring method in geotechnical centrifugal tests so as to facilitate further in-depth analysis.
Highlights
In geological, geotechnical and environmental engineering, centrifugal tests for small-scale physical slopes can reproduce the deformation process of large-scale slopes [1,2], which is an important method for understanding the behavior of slopes
The feasibility and validity of the monitoring system is verified by a comparison between the results of fiber Bragg grating (FBG)-based sensors and those of a numerical simulation
Zhang et al [21] conducted a FBG-based centrifuge model test to investigate the internal deformation of soil and the failure of a slope
Summary
Geotechnical and environmental engineering, centrifugal tests for small-scale physical slopes can reproduce the deformation process of large-scale slopes [1,2], which is an important method for understanding the behavior of slopes. Zhang et al [21] conducted a FBG-based centrifuge model test to investigate the internal deformation of soil and the failure of a slope. The strain variation during the pressing-in of piles with FBGs attached was monitored and the relationship between the lateral friction resistance and the S/d ratio was revealed in a centrifugal model test [22]. An FBG-based system was developed and the failure process was investigate, by monitoring the surface displacement and strain changes in the anchors and anti-sliding piles [23], but the surface displacement is merely the sum of the longitudinal displacement at this point, which can’t reflect the internal displacement distribution. 0, the derived (6) is applied to calculate deflection of the the deflection of inclinometer: the inclinometer:
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