Soil landslides have strong suddenness and high destructive potential, while traditional reinforcement technologies are limited by large construction disturbance and poor terrain adaptability. This study focuses on a typical silty clay landslide in Jiangxi Province, China. Anchor cable micro-pile clusters are a new composite retaining structure applied in landslide control; however, their three-dimensional collaborative bearing mechanism and design methods remain unclear. Based on Pasternak’s two-parameter foundation beam theory and the ideal elastic-plastic p-y curve of soil around piles, this study establishes a theoretical analytical framework considering pile-soil-anchor cable interactive deformation. FLAC3D numerical simulations and physical model tests with a length scale of 1:10 and a diameter scale of 1:5 was conducted to investigate the effects of pile diameter, spacing, and anchor-cable tension on foundation bearing capacity. Taking the same micro-pile group without anchor cable prestress (T = 0 kN) as the traditional micro-pile baseline, the optimized anchor cable micro-pile cluster at the recommended prestress of T = 50 kN increases the safety factor from 1.52 to 1.78, i.e., by 17.1%, and under the ultimate loading stage, reduces the pile-top displacement from 15.6 mm to 8.7 mm, i.e., by 44.2%. The optimal spacing is five times the pile diameter, with a pile group efficiency coefficient of 0.92. When anchor prestress exceeds 50 kN, reinforcement benefits gradually decrease, and 50–60 kN is recommended. Plum-shaped pile arrangements outperform rectangular layouts, and three rows of piles can satisfy anti-sliding requirements. The calculation error is less than 5%, demonstrating its applicability for slope stabilization engineering in similar silty clay landslides.
