Grouting Anchor Pile Foundation Treatment Works

Anchoring for soils and rocks is an important branch in the area of geotechnical engineering. The technology of anchoring for soils and rocks can fully transfer and raise the abilities of self-intensity and self-stability, improve the stress condition, enhance the stability of structure by using the inside-resistance of rocks-soils body, thus improve the security in the course of construction,The technology of anchor bar, because of easy, economic, and secure to construct, was using to hold the roof of coal mine from the beginning of twenties century. It gained a very big improvement on the theory and the practice for dozens of years. Many domestic and foreign companies use analytical methods of theoretical analysis, model experiment, field analysis, etc. to provide theoretical basis for anchor bar designing and constructing of complicated stratum. At the same time, our country and some region and department concerned have published relevant specification for anchor bar designing and constructing. Fumble and use in practice have a tendency to exceed the theory. In our country, the technologies of anchor bar have a wide using in the area of slope treatment, bridge,tunnel, underground-project, mine, foundation pit and the structure of resistance to buoyancy and inclination, etc. Developed to present, it become one of the best ways of economic and effective in improving the stability of geotechnical engineering, solving the problem of stability in complicated geotechnical engineering, and decreasing the construction' s difficulty of the built-in piles.Grouting anchor bar is one of types of anchor bar, which is most in use in the technology of anchoring for soils and rocks. This paper is in the light of the example of pile foundation disposal of the Long Yin Gang Bridge. First, it uses the theory of anchoring and takes the shearing stress of piles as the designed value of bolt-locking force. We have a bold try in the practice by using the designing and constructing way of taking steel rails as anchor bars. This way can fully use the resistance-extension intensity of steel rails attaining the goal of designed bearing capacity. It can decrease the built-in depth effective. It can decrease the construction' s difficulty and enhance the stability of pile foundation in the complicated stratum through the way of using three to five small anchoring piles in the same pile foundation. Second, the small steel bar cage was used to strength the pile foundation in the area of Karst cave developed. It can play a positive role in enhancingthe bending-resistance and torsion-resistance. Especially, it can make things convenient for construction because the steel bar' s arrangement in the cage is distributed over all around, and is easy to install the pouring piles at the center. The separation angle of anchor bar and horizontal line was generally designed to ten to forty-five degrees. But in this project because pile foundation mainly bear vertical pressure, the separation angle of anchor bar and horizontal line was designed to ninety degrees. And the pile foundation was designed to have no bearing plate and anchorage. It can achieve the same results. We use grouting anchor bar in the construction, and take the role of filling, penetrating, compacting of cement grout to achieve the club-footed pile' s result. So the plan of pile foundation disposal is reasonable, economic and secure. It fully achieves the desired results. It plays a certain reference and guidance roles to the designing and constructing of the similar project.