| Most of the bridges built in the early years are subjected to conditions, generallyused gravity pier foundation, their size, weight and waterproof area are large, and thusthe basis of these bridges impacted by the erosion is particularly significant Recentyears，many bridge destruction events are caused by flooding erosion, huge casualtiesand property are loses. It becomes an important factor that the pile instability causedby bridge pile soil river erosion, it has an important engineering significance to carryout stability evaluation of the erosion bridge. The detection method of the bridgefoundation scour diversified, single-beam and multi-beam measurement methods areadopt, however, these methods are highly error costs, subject to environmental impact,monitoring method could been continuous in situ is rarely. In this paper, by theresearch of soil resistivity, we developed the pile soil probe dipped in a certain depth;the probe could be used for real-time monitoring of the top interface soil elevationchange. Based on the mechanism of bridge pile foundation scour and erosion analysis,we discuss the impaction cased on the stability of the bridge foundation, and buildmight exist in the mechanical erosion model. We got the calculation method forcedchange process and the stability describing criteria on the bridge pile foundation. Theultimately we developed monitoring data processing and stability determine software, Andwe realized large-scale bridge piles security evaluation and early warning.The paper is divided into four chapters. The first chapter mainly described thebridge pile in situ monitoring, resistivity testing technique, bridge piles the erosionstability of the situation related research at home and abroad, thesis research purposes,content, technology roadmap and research and innovation. Chapter Two studies on insitu monitoring system design. We described the probe developed from the electrode probedesign, structure and materials etc. Study the measured apparent resistivity curves reflect theability of the soil and water interface by resistivity probe through laboratory experiments. Wedesigned the main part of the hardware and software, achieved data acquisition and remote transmission. Based on the significant differences in resistivity of the water andsediment we infer soil and water interface position, we obtain apparent resistivity withdepth curve distribution by experiments, verify the accuracy of the probe to determinethe water interface, and discuss the changes in the rates with depth of the probe whenthe abnormal situation of apparent resistivity. Chapter Three we analysis the type ofbridge erosion foundation stability, research and bridge pile force condition andanalyze the stability of the pile. We analysis three cases of loss of bearing capacity,such as displacement on the pier sliding, subsidence, overturning. Build the formulaof stability determine. Research force of the bridge piles under differentcircumstances and the software of stability determine, entering the known parametersof the bridge piles as well as the data detected by probe, determine the stability of thebridge piles, The ultimately we realize large-scale bridge piles security evaluation andearly warning. Chapter Four gives the overall conclusions of the paper and next steprecommendations.This thesis is based on dynamic real-time observation of resistivity changes in theriver bridge piles in the surrounding water interface position; we determined thestability of the bridge piles by the software, realized real-time observation on the riverwater interface changes. Research is mainly applied to the real-time monitoring offlood or strong erosion status, and appropriates warning according to monitoringresults, prevents the sudden destruction disasters of bridges caused by the scouringeffect. |
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