Advanced Sensing for Real-Time Monitoring of Geotechnical Systems

Abstract

Landslides, lateral spreading and other similar forms of ground failure due to natural disasters impact communities around the world. These ground failures continue to result in human suffering, billions of dollars in property losses, and environmental degradation. As our society becomes ever more complex and urban areas continue to spread, the economic and societal costs of landslides and other ground failures will continue to rise. Although our understanding of the mechanisms of failure and large ground deformation due to rains, floods and earthquakes have improved considerably over the last two decades; the goal of significantly reducing losses from ground failure due to natural hazards remains elusive. This state of affairs stems from the limitations of existing real-time sensing and monitoring tools as well as inadequate predictive capabilities of current computational models. Real-time monitoring programs are essential to develop warning systems of impending danger from active landslides in any site specific or regional hazard program. The current state-of-the-art in real-time monitoring of active slopes is either based on very expensive monitoring systems or on measurement of ground surface displacements. The work presented in this paper constitutes a major step in the direction of establishing a low cost real-time monitoring system for active ground. A ShapeAccelArray sensor is being developed, taking advantage of promising new advances in the fiber optic and micro-machined electromechanical sensor (MEMS) technologies (Danisch et al., 2004). This sensor array is capable of simultaneously measuring acceleration and permanent ground deformation down to tens of meters of depth. The sensor array would be capable of measuring in situ (field) 3D ground deformation as well as 2D soil acceleration at 0.5 m to 1 m intervals. The paper presents the preliminary design of the new sensor array as well as preliminary results from tests aimed at validating and calibrating the accelerations and displacements measured using the newly developed sensor array. The accelerations and displacements measured using the ShapeAccelArray sensor are compared to those measured using traditional accelerometers and displacement sensors. Finally, conclusions are drawn on the effectiveness and accuracy of the new sensor array.