أرسل هذا في رسالة قصيرة: Effect of a circular tunnel on ground acceleration responses during earthquakes

  _____     ______              ______            
 /  ___||  /_   _//     ___    /_   _//     ___   
| // __     -| ||-     /   ||   -| ||-     /   || 
| \\_\ ||   _| ||_    | [] ||   _| ||_    | [] || 
 \____//   /_____//    \__ ||  /_____//    \__ || 
  `---`    `-----`      -|_||  `-----`      -|_|| 
                         `-`                 `-`