Anchoring Mechanism and Bearing Characteristics of the Inflatable Controlled Anchor

Abstract

The support technology of temporary slope engineering such as building foundation pit, has the problems of small anchorage force, non-recyclable and excessive length of anchor. Focusing on these issues, this study puts forward a new support structure system named as inflatable controlled anchor. This new type of anchor was designed and manufactured for field test. To investigate the performance of the proposed anchor, a series of full-scale field model tests were carried out with the variables of inflation pressure, anchorage length, embedment depth, and steel strip thickness. The results show that the bearing capacity of inflatable controlled anchor mainly depends on the friction resistance between the steel strips and the hole wall. The rubber membrane as an independent part only provides the compressive pressing to steel strips, and the bearing capacity can be greatly improved by increasing the inflation pressure. The bearing capacity of the anchor is also improved by the increasing of anchorage length and embedment depth. If the thickness of the steel strips is too thin, the steel strip has obvious bending deformation under inflation pressure, which affects the anchoring effect, so the thickness of steel strip has a critical value of 5 mm. According to the experimental results, the working mechanism of inflatable controlled anchor is discussed, and the calculation method for the bearing capacity is proposed. The calculated values of the proposed formula are basically consistent with the experimental results, which verifies the correctness of the formula for forecasting the bearing capacity of inflatable controlled anchor.