The front side of the hand-dug shield is equipped with excavating machinery and excavating device, which is called semi-mechanical shield。The excavating device has three forms: bucket type, cutting type and mixed type。Shovel type is suitable for clay and gravel mixed layer, cutting type is suitable for hard clay and hard sand layer, mixed type is suitable for good self-supporting soil layer。If the soil is hard, the cutting head of the soft rock boring machine can be installed。Its application scope is basically the same as that of hand-dug shield。