Field Experimental Study on the Load-Carrying Performance of Pressure-Type Anti-floating Anchors

Abstract:

In order to deeply study the bearing performance and displacement law of pressure-type screw-thread steel bars for the prestressing of concrete (PSB) anti-floating anchors, this study took an actual anti-floating project in Qingdao as the background, and carried out field experimental study on three pressure-type PSB anti-floating anchors. The load-displacement evolution law was systematically analyzed by monitoring the displacement changes of anchor bars and grout body in real time, and the bond stress distribution characteristics of PSB anti-floating anchors were revealed. The test results show that the displacement of the anchor bar and grout body increases linearly with the load growth, which is significantly affected by the load level; when the load reaches 60% of the maximum load, the displacement curve rises abruptly and enters an accelerated growth stage; the overall growth of the grout body-displacement curve is linear, with no abrupt change point or bilinear characteristics. The relative displacement between anchor bars and grout body increases with the increase of load. Under the experimental conditions, the average bond stress of the pressure-type PSB anti-floating anchor bar-grout body interface is 0.73 MPa, while the average bond stress of the grout body-rock and soil mass interface is relatively low, which is 0.104 MPa. The bond stress at the interface between the grout body and the rock and soil mass is related to the anchoring length and the anchor hole diameter, and the excessive anchoring length and the anchor hole diameter will reduce the bond stress at the interface between the anchor bar and the grout body.