Soil nail and soil body can combine together and form compound body, which will promote slope stability and carrying capacity, improve ductility, avoid collapse and benefit for construction security.

1. The framework restraint function of soil nail.

Because of soil nail’s self stiffness and intensity, compound body is formed when it inserts into soil, which becomes an integral whole and has restraint for deformation of soil.

2. The load-sharing function of soil nail.

In compound body, soil nail and soil body bear load and stress together, so it has the load-sharing function. Because of soil nail’s high tensile, shearing strength and bending rigidity, stress is transferring gradually to soil nail after reaching plastic state. When fracture is appeared, it is more prominent for soil nail’s load-sharing function. There are several factors affecting proportion of soil nail’s load-sharing: relative stiffness, spatial position and stress level of compound soil.

3. Stress transfer and diffusion function of soil nail.

When load reaching a certain extent, crack on slope surface and inside soil has developed into a certain width, at this time, the stress is largest. Partial stress transfers to stable soil body and diffuses in large scale soil, which reduces the concentrated degree of stress.

4. Restraint function of slope deformation.

Installing reinforcing mesh sprayed concrete face on slope is an effective component of soil nail. It has restraint function for slope’s deformation, which depends on frictional resistance between soil nail and soil body.