Construction method of tough protective structure of open cut tunnel of high abrupt slope

The invention discloses a construction method of a tough protective structure of a high-abrupt slope tunnel open cut tunnel. The tough protection structure comprises an open cut tunnel arch foot foundation and a multi-layer gabion cage arch structure. The gabion cage fully utilizes and digests a part of hole slag; the impact kinetic energy of high-potential-energy rockfall and avalanche is absorbed by utilizing the toughness and energy absorption capacity of the gabion cage. According to the implementation of the open cut tunnel foundation, the foundation is built at the arch foot position, and different foundation forms are designed according to different geological conditions. The method has the following advantages: (1) the hole slag of the tunnel in the alpine and gorge region is difficult to treat, the open cut tunnel is constructed by using the gabion cage, the hole slag is reasonably utilized, and the waste slag is reduced; and (2) the basalt fiber and the hole slag belong to low-carbon environment-fri