Study on the technology of shotcrete support for broken surrounding rock in Xishimen iron mine

In order to solve the problems of high cost and unsatisfactory performance of arch support in the roadway of skarn and better integrity ore parts in the northern area of Xishimen iron mine, anchor net spraying technology is adopted to support the roadway.In order to obtain the ideal support effect, the support parameters need to be studied.Firstly, point load and structural plane surveys were performed.Based on this, the generalized Hoek-Brown strength criterion was used to reduce the physical and mechanical parameters of the rock blocks to obtain the mechanical parameters of the ore body and skarn.Secondly, the Q values of the ore body and skarn were calculated according to the Q system rock mass classification method, and the supporting parameters were selected and the construction scheme is formulated.Finally, numerical simulation verification of the support effect of the roadway is carried out according to the design scheme, and it is applied in practice.The results show that:for skarn and ore parts that are not subjected to mining pressure, the use of 2.4 m long anchor rods for bolt-net-spray support can meet the requirements of stability.Under this premise, 1 800 yuan can be saved in the support cost of per meter roadway.