Analysis of Deformation and Failure Characteristics of Rock Anchor Foundations in Limestone Strata of Southern Anhui Mountainous Areas

Jiaming Jiang¹Weidong Cheng^2*Xiaodong Cheng²Qiuyang Hong^2*

• ¹School of Materials and Chemical Engineering, Anhui Jianzhu University, Hefei, China
• ²Anhui Jianzhu University, Hefei, China

This study investigates the deformation and failure characteristics of rock anchor foundations in the limestone strata of southern Anhui's mountainous regions, employing a multi-scale methodology combining field tests, laboratory experiments, and numerical simulation. The core findings provide critical quantitative thresholds for engineering design. A critical anchorage depth of approximately 3500 mmwas identified, marking a shift in failure mode: at depths ≤3000 mm, failure occurs by pull-out along the rock-grout interface, while at depths ≥4000 mm, failure transitions to tendon extraction from the grout, with peak capacity observed at 3000 mm depth. Group anchor systems (2×2 configuration) demonstrated a significantly enhanced ultimate pull-out capacity of 3600 KN, a four-fold increase over a single anchor, due to stress superposition. An embedded rock depth of 400 mm was found to be the optimal threshold for improving structural ductility. Furthermore, parameter sensitivity analysis established an optimal diameter ratio criterion of D/d ≥ 3.2as the core parameter for optimizing pull-out performance. These quantitative findings offer direct theoretical support and a practical basis for the design optimization of rock anchor foundations under similar geological conditions.