Health State Evaluation Of Under-Water Shield Tunnels Based On Fuzzy Cluster-Time Series Model

Under the background of continuously developing tunnel engineering and Tunnel Health Monitoring,the research progress of tunnel health state analysis,both its theory and analytic techniques,is relatively backward.In this article,the definition of the Tunnel Operating Health State is given and its connotation is also extended.Additionally a real-time tunnel operating health state evaluation model for the whole tunnel structure,based on the Fuzzy Set Theory and Time Series Analysis,is proposed together with the abnormality detection strategy based on the tunnel structural performance analysis.The proposed evaluation model is applied to Nanjing Changjiang Shield Tunnel for its real-time and over-all operating health state analysis in order to obtain its dynamic changing characteristics.During the process of modeling and engineering application,a series of findings are achieved and listed as below:(1)The operating Health State of a tunnel is defined and its connotation includes real-time health state and over-all health state.Based on Fuzzy Set Theory,the mathematical meaning of this new definition is presented.With the advantages of continuous-valued logic,the new definition provides a more accurate and more realistic way to describe the developing process of the tunnel operating status.(2)FC-STW evaluation model is a combination of the Fuzzy Cluster analysis and the expanded high-dimensional Sliding Time-Window method.With the anti-fuzzy property test and the real-time evaluation test,the proposed model is verified to be capable of processing both multi-factor and real-time monitoring measurements.Thus the model can well match with the Tunnel Health Monitoring system.(3)An abnormality detection strategy based on the tunnel structural performance analysis is proposed in this article.Stochastic Error and Local Abnormality are separately defined as two different kinds of abnormal data.By designing the Point Anomaly Test and the Set Anomaly Test,the proposed strategy can be verified.While focusing on the abnormal operating status detection,the Information Analysis Technology and Data Mining are introduced into tunnel health state analysis,which is a new inspiration for the future development.(4)The engineering case study is conducted on the Nanjing Changjiang Shield Tunnel.The real-time operating health state curve,depicting the dynamic changing characteristics of the whole tunnel structure,indicates that a tunnel is a dynamic structure during its operation,tends to stabilize itself gradually and fluctuates seasonally due to the annul changing environmental geological conditions,which is a useful information for the tunnel maintenance system.