Analytical Study on the Pullout Distribution of an Anchor with Multiple Grout Bulbs

An important research topic in reinforcing deep soft soil slopes is the pullout distribution of a long anchor with multiple grout bulbs under various factors. The nonlinear variation between the compaction effect and grout bulb diameter was first quantitatively described using an exponential model. The pullout force of a long anchor with multiple grout bulbs was then calculated using a modified model considering the compaction effect. After verification based on the model test data, a parametric analysis was carried out on the elastic modulus of the anchor rod, grout bulb diameters, bulb numbers, and bulb sequences. The results indicated that a larger elastic modulus leads to a more obvious hardening behavior and a lower mobilized displacement of the pullout force. The grout bulb diameter significantly influences the ultimate pullout force and the mobilized displacement of the pullout force. Although the bulb number affects the ultimate pullout force and the distribution of the pullout force, the mobilized displacement of the pullout force does not change. For a long anchor with multiple grout bulbs, the sequence of the bulb diameters has a significant impact on the ultimate pullout force and the distribution and mobilized displacement of the pullout force.