Manual Excavation
Method

Hand Dug Tunnelling is a traditional form of trenchless method, which can be formed location with imited working space locations. The soil is usually stabilize by chemical grouting injected into the ground to allow more stability. Sheetpiles or U-Channels are driven horizontally into the ground ahead to form a rectangular or square shaped
tunnel. The excavation is carried out by manually excavation the soil out within the driven supports. Portal frames are installed inside the tunnel to provide additional suport to the tunnel.The advantage of this trenchless method is the tunnel alignment can be curved in both horizontal and vertical direction, or even 90 degrees perpendicular which allows greater flexibility in congested locations.