<p>Pressurized hydraulic tunnel linings undergo long-term cyclic loading from static water pressure and hydraulic transients, causing cumulative concrete damage that affects structural safety and service life. This study examines the coupled effects of compaction and damage in saturated concrete under cyclic loading, addressing gaps in current damage models. Equal amplitude cyclic uniaxial compression and splitting tensile tests are performed on C30 and C50 concretes. At low cycle counts and load amplitudes, compaction dominates, increasing compressive strength by up to 5% for C30 and 2.5% for C50, and enhancing C50 tensile strength by 15.17%. At higher cycles and medium-to-high loads, damage accumulation prevails, reducing compressive strength by up to 20.05% for C30 and 15.31% for C50; tensile strength degradation also intensifies with load. Low-strength concrete shows rapid damage growth and plasticity, while high-strength concrete maintains compaction effects and hysteretic strengthening up to 50 cycles under low loads. A damage evolution model, integrating Basquin and Paris equations with compaction effects, predicts strength and modulus degradation accurately, with determination coefficients exceeding 0.86. These findings clarify the nonlinear interaction between damage and compaction in saturated concrete. A novel damage evolution model, integrating the Basquin and Paris equations with a compaction term, is proposed. This model uniquely captures the dual effects of strength degradation and compaction-induced recovery, providing a more accurate theoretical basis and a potential tool for fatigue life assessment.</p>