Non-uniform shear stress design method for pressure-dispersive anchors

The existing studies indicate that the shear stress between grout body and rock mass along the anchoring segment of a prestressed anchor is not uniform. The non-uniform shear stress design method is one of the development trends for prestressed anchor design, but the current design methods still treat the shear stress as uniform one. The reason lies in that widely recognized shear stress distribution pattern and formula have not been established. However, the bearing capacity of pressure-dispersive anchors is much higher than that of the tension ones, which means that the shear stress between grout body and rock mass in anchoring segment is more concentrated. So the non-uniform shear stress design method is more necessary to pressure-dispersive anchor. Three indoor full size simulating experiments are undertaken to get the shear stress, and multi-factor numerical simulations are done to discover distribution characters of the shear stress. Two distribution patterns are drawn from the indoor tests and calculations, and key parameters of the shear stress distribution curves are confirmed through the numerical calculations. Equation derivations are done based on the two distribution patterns, and a non-uniform shear stress design method of pressure-dispersive anchor is finally established. It is proved that the proposed method agrees with the indoor experiments and numerical simulations.