| With the rapid economic development of China, tunnel engineering has being developed extensively around the country, and there are more and more large-scale tunnel projects under construction. Shield method has increasingly being favored by builders due to its inherent advantages in terms of construction technique, and there are more and more tunnel projects adopting shield method for construction. Construction safety has always been the most concerned issue for builders who carry out tunnel project with shield method, moreover, how to obtain monitoring information and judge the safety state of tunnel is the key to safeguard construction safety. For long and large tunnel projects, how to solve these problems is especially urgent.To solve the problem of judging tunnel's construction safety state, this paper carries out research on the following factors concerned about shield method construction of tunnel: automatic monitoring, analysis of monitoring data, advance alarm and alarm of safety state.First, this paper studies the insufficiency of traditional monitoring methods, and analyzes the advantage of adopting automatic monitoring in large-scale tunnel engineering; then, an automatic monitoring scheme is designed for the Chongming tunnel so as to satisfy the need of data in construction.Second, this paper introduces wavelet transformation method into the treatment of monitoring data. This paper also carries out study on error handling principle based on wavelet analysis, and by selecting reasonable wavelet function and threshold, the error handling of monitoring data is realized and the results are satisfactory.Thirdly, based on previous theories, this paper proposes the deformation mechanism and rules during the advancing process of shield tunnel, and analyzes the front pressure balance principle of shield, so as to making the preparation for further research.Fourthly, through the analysis of present alarm value within China, this paper... |
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