Shinji Konishi

DETECTING OF VOIDS NEAR SURFACE IN BOX-TYPE CONCRETE SEGMENT OF SUBWAY SHIELD TUNNEL WITH INFRARED THERMOMETRY

The state of temperature environment in the tunnel was cleared due to long term measurement of tem-perature in the tunnel by fixed thermometers in a section of a shield tunnel with box-type segments for the purpose of developing a non-destructive and contact free method using infrared thermometry to detect non-visual voids effectively. Moreover, the authors carried out every seasonal movement measurement by an infrared thermography and compared with results of hammering tests found some voids. From the results, follows were cleared. Winter season was suitable for the detection with the method in the area of the investigation. Accuracy of voids by infrared thermometry was approximately equal with it by hammering test when the temperature at measurement satisfied temperature environmental conditions. 鉄道トンネル内において表層コンクリートの浮きを赤外線パッシブ法により，非破壊・非接触で効率的に検査する方法を検討するために，中子型セグメント構造のシールドトンネル区間において，温度計を設置して坑内温度計測を行い長期にわたる坑内の温度環境を把握し，季節毎（8月，11月，1月）の赤外線サーモグラフィによる移動計測を行い，浮きを検出し打音法と比較した．その結果，今回の調査範囲においては，11月~1月が調査に適した期間であること，赤外線熱計測による浮きの検出は，計測時の温度環境の条件を満たせば打音調査に対して概ね同程度の精度を確保していることが明らかとなった．

SHIELD TUNNELING ADVANCEMENT SIMULATION USING 3D FEM CONSIDERING DISTANCE FACTOR AND ITS VALIDATION

A new approach of shield tunnel advancement for soil deformation calculation is presented using 3D finite element method. Applying step by step tunneling loads in this method, total soil deformation is calculated by summation of induced displacement from the first loading step to the current step deformation. In this approach, shield machine face distance from monitoring locations is taken as a factor which affects way of calculating soil displacement. If TBM machine face distance from the monitoring location is assumed to be less than a specific distance say “D”, drained condition is used to calculate soil deformation; on the other hand, if the machine face distance from monitoring location is more than “D”, undrained condition is used for soil deformation calculation. Additionally field data of an EPB shield tunneling site were gathered and used to investigate the validity of proposed approach.