Open cut tunnel containing iron sand counterweight layer and construction method of open cut tunnel

The invention relates to an open-cut tunnel containing an iron sand counterweight layer. The open-cut tunnel comprises a tunnel bottom plate, tunnel side walls, the iron sand counterweight layer and a tunnel internal road surface. The tunnel side walls are located on the left and right sides of the tunnel bottom plate, the iron sand counterweight layer is laid on the upper end face of the tunnel bottom plate, and the tunnel internal road surface is constructed on the upper end face of the iron sand counterweight layer. The invention further relates to a construction method of the open-cut tunnel containing the iron sand counterweight layer. The construction method comprises the following steps that a, the tunnel bottom plate and the tunnel side walls are constructed; b, constructing an iron sand counterweight layer, paving layer by layer, and compacting layer by layer; and c, constructing a tunnel internal pavement including a road pavement base layer and a pavement surface layer. The method is easy and conve