J. Tanner Blackburn

Automated Monitoring of Supported Excavations

This paper describes remote and automatic monitoring systems for measuring vertical and horizontal displacements and tilt of structural elements. An automated total station and system of tiltmeters were employed at the excavation for the Ford Engineering Design Center. The 9.1-m-deep excavation was made through fill and soft clays and undercut the shallow foundations for a building 6 m from the edge of the excavation. The excavation support system consisted of a sheet pile wall supported by two levels of cross-lot and diagonal internal bracing. The two automated systems, the structural support system and construction details are described. Selected ground and structural responses collected by the automated systems are compared to those collected with conventional methods. The accuracies of the measured automated responses are discussed. The tilt meter data are shown to supplement the inclinometer data so that structural responses of an adjacent structure to the excavation can be evaluated.

Representing internal bracing systems in 3-D models of deep excavations

Internal bracing in conventional 2-d finite element models of deep excavations is modeled by averaging the stiffness of the internal braces over their spacing and considering the bending stiffness of the wall about its neutral axis in the plane of bending. The effects of the waler connecting the brace and wall are usually ignored. When making a 3-d simulation, each internal brace can be modeled individually. In this case, when evaluating the 3-d distribution of ground movements and structural responses, the effects of the waler should be considered. However, it is not feasible to explicitly model each waler and all the connections between the brace, waler and wall. This paper summarizes the considerations related to such simulations, presents the results of parametric studies that show the effects of sheeting flexibility parallel to the wall and compares results of 3-d finite element simulations to responses at the Ford Design Center excavation in Evanston, IL.

Development and Evaluation of Automated, Wireless Instrumentation for Geotechnical Monitoring

This extended abstract describes the development of an expandable wireless sensor node to monitor potential landslide hazards in remote locations. The development and evaluation aspects are described in the following order: data transmission, power management, and field evaluation. Brief conclusions are presented, along with a discussion of future and ongoing research.Copyright