Application of Self Drilling Anchor Bolt in Deep Foundation Pit Supporting

In recent years, urban buildings are developing toward high-rise, and the application of underground space in construction is more widely, which brings tremendous pressure to the maintenance of deep foundation pit.

In conventional soil nailing projects, soil nails must be placed after drilling holes, and pour the cement grout into the holes where the steel bars are placed. The leakage part of steel bars should be solidified with the steel mesh and concrete on the slope. But when it comes to the soil mass which is soft and contains a large amount of sand, it is easy to collapse and shrinkage in the process of drilling and cause soil and water loss. This type of support greatly reduces the bearing capacity of the foundation.

In this case, the self drilling anchor bolt can be used as supporting tool. The anchor bar is permanently retained in the soil layer after drilling to a certain depth, and the cement slurry is injected into the hollow structure during the rotation of the anchor bar. Cement slurry solidifies in the process of anchor bar rotation and fastens the anchor bar to the foundation. This support pattern not only avoids the problem of soft soil collapse, but also achieves the effect of anchoring foundation. Moreover, the self drilling anchor bolt is convenient and rapid to construct, and it can adapt to a variety of soil properties, so it has a bright prospect in the future.