Abstract
In this report, the effective and economical design methods for reinforcing the shield tunnel of underground transmission cables in the case of the changes of external loads are described. First, the necessary of reinforcing were evaluated based the maximum of external load changes. Then, the soundness of a tunnel was evaluated by both site measurement of present external loads and structural calculation. The effective and economical design methods were studied by focusing on the concept of changing reinforcement specifications according to reinforcement duration, and considering the measurement method of external loads. The reinforcement range and interval in the longitudinal direction of a tunnel were designed based on the results of site measurement. Moreover, the simple load test on an existing tunnel was conducted for investigating the mechanism of a tunnel and improving the accuracy of the design methods and structural calculation methods.
