How to Choose the Type of Soil/Rock Anchor System?

With the continuous development of urbanization, the number of deep foundation pit projects is increasing, and soil/rock anchor technology has received widespread attention.

According to the different types of anchoring sections in the cable, the soil/rock anchor system can be classified as the following: ordinary tensioning anchor system, tension-dispersive anchor system, pressure-dispersive anchor system, and tension-pressure composite anchor system. Different types have their own advantages and disadvantages.

1. The ordinary tensioning anchor system has a simple structure, convenient construction, and low cost. However, the tensile stress in the upper part of the bond length is concentrated, and the slurry is easy to crack, which will affect the anchoring effect.

2. The strands of the bond length of the tension-dispersed anchor system are dispersedly arranged, and the tension load is dispersedly transmitted to different depths of the cable, which can effectively solve the problem of tensile stress concentration. However, since the bond length is twice that of the ordinary tension type, the hole drilling depth needs to be increased. Moreover, due to the different lengths of the strands in the free length, the deformation of the strands is uneven after the deformation of the rock, and its adaptability to deformation is poor.

3. The pressure-dispersive anchor type and tension-pressure composite anchor type anchor system can significantly improve the stress conditions of the anchoring section, effectively improve the anchoring effect, and the free section length is increased compared with the ordinary tension type with the same hole depth, which can better adapt to the deformation of the rock mass. However, due to the complex form of the inner anchoring section, the installation and tensioning are cumbersome, which increases the construction difficulty and the engineering cost.

Under normal geological conditions, the ordinary tensioning anchor system with simple structure, convenient construction, and low cost is selected, which can not only meet the needs of the project, but also effectively improve the construction efficiency, speed up the construction progress, and easily control the project costs. For local slopes with complex geological conditions and poor rock conditions in the anchoring section, tension-dispersed, pressure-dispersed, and tension-compression composite anchor systems can be selected to ensure the project quality.