Tunnel constraint anchor cable and method for improving stability of initial support structure

A tunnel constraint anchor cable, comprising steel strands (1) anchored in surrounding rocks, first anchor plates (2) and first anchorage devices (3) installed on surfaces of the surrounding rocks, longitudinal connection members (5) installed between two adjacent steel ribs (4), and second anchor plates (6) and second anchorage devices (7) installed on the longitudinal connection members (5), wherein

• the longitudinal connection members (5) are arranged between the two adjacent steel ribs (4) for initial support, and a third preformed hole (8) for the steel strands (1) to penetrate through is set in a center of each longitudinal connection member (5);
• a first preformed hole (9) and a second preformed hole (10) having diameters larger than diameters of the steel strands (1) are respectively formed in a center of each first anchor plate (2) and a center of each second anchor plate (6);
• and one end of each steel strand (1) is anchored in the surrounding rocks, and the other end penetrates through the first preformed holes (9) and the second preformed holes (10) in sequence, and the first anchorage devices (3) and the second anchorage devices (7) respectively lock the steel strands (1) after the pretightening force is applied.