The related investigations show that there are many differences in views of academic and engineering circles about the definition and the work mechanism of soil nailing and composite soil nailing.

There exists a chaotic phenomenon in deep foundation pit bracing by soil nailing at present. How to design a soil nailing bracing becomes a key and urgent problem in geotechnical circle.

The carbides in the matrix prevent dislocation from moving, and pin effect of the carbides in the grain boundary keep grain boundary from sliding, and creep resistance of steel is improved.