The invention discloses a combined supporting device consisting of a net stand and concrete and an application thereof in the underground
engineering. The net stand is composed of a plurality of horizontal, vertical, cable-stayed connecting
pipe fittings connected by multidirectional joints, and an anchor rod and an anchor
pile are connected with the net stand through a pad and nuts, and connected with surrounding rock at the other end, wherein the gap between the net stand and surrounding rock is filled with the concrete. The application comprises the steps of manufacturing of multidirectional joints and connecting
pipe fittings, connection of steel
bushing cylindrical joints and the net stand, hanging of steel net pieces between net stand and surrounding rock and filling of filling backboard bag with concrete or sprayed concrete after the installation of the net stand, and hanging of a flexible film pump at the inner side of the net stand to inject the concrete to form the net stand and concrete combined support. The invention is characterized by ready-to-install structure, simple use, low cost, good entirety and rational structure stress to co-load the
ground pressure through the entirety formed by the net stand and surrounding rock. The invention is especially suitable for the tunnel support of bad grounds which contain water and feature quagginess and fractures and other complex stratums, and is widely used for the temporary or permanent support of subsurface
engineering such as mine workings, traffic tunnels, water conservancy and national defense.