Several Questions for Ensuring Quality of Soil Nailing Engineering
Soil nailing is a reliable, easy and low-cost supporting structure, which has been used in many kinds of foundation pit excavation engineering. Also, several questions about construction of soil nailing need to be noticed in advance to ensure quality of engineering.
1. Excavation depth of each layer.
Construction of soil nailing is layered, from top to bottom, first excavate one layer and then support one layer. Before installing soil nail, it’s easy to appear partial collapse and even whole structure destroy. So after excavation of every layer, soil nail should be installed rapidly. At the same time, excavation depth of each layer should not be too deep to ensure structure’s safety.
Soil nailing support generally adopts pressure grouting. Soil nailing hole should be fully filled, in order to avoid weakening function of soil nailing and influencing stability of entirety.
During process of soil nailing construction, underground water should be drained away effectively. Underground water has thread for construction and function of soil nailing, so it should be lowered under excavation face.
4. Installing angle of soil nailing.
It’s indicated by test that soil nailing can be stressed only small deformation of soil body occurs. To give full play of function of soil nailing, installing direction of soil nail should have certain angle with soil body’s possible shearing slip face, which can make soil nail be stressed and enhance soil body’s shear strength. Generally, it’s believed that installing angle of soil nail should be slanting downward about 0°～15°.