Rock material internal blasting crack propagation speed sensor and testing method thereof

The invention discloses a rock material internal blasting crack propagation speed sensor and a test method thereof. The sensor comprises a substrate, an enameled wire and a Dupont wire. The base is made of mica sheets and is in the shape of a plurality of concentric rings nested on the same plane, and the rings are fixed through connecting bridges. An enameled wire is adhered to the surface of each circle of circular ring along the ring body, and the end parts of the two sides of all the enameled wires are guided to the main connecting bridge; a plurality of Dupont wires are bonded on the surface of the main connecting bridge along a bridge body, and the Dupont wires respectively complete electric connection between the enameled wire and an external detonation velocity instrument; when a rock model is manufactured, the blast hole prefabricated part and the sensor are packaged into the rock model together; during blasting test, the expansion speed of rock blasting cracks between the enameled wires is calculate