[Objective] Autogenous volume deformation is a key factor affecting the cracking resistance of dam concrete; however, its meso-scale mechanism is often neglected in engineering practice. Meso-scale modeling of full-graded dam concrete has long faced challenges of low efficiency and poor mesh quality, particularly in reconciling, within a unified model, the scale disparity between a maximum aggregate size of up to 150 mm and an interfacial transition zone (ITZ) thickness of only about 50 μm, which prevents accurate representation of the true meso-structural characteristics. To address this issue, we propose a random aggregate batch placement method. [Methods] By optimizing the aggregate generation algorithm and introducing an efficient spatial positioning criterion, rapid placement and high-volume simulation of four-graded aggregates were achieved. An adaptively coordinated meshing technique for the interfacial transition zone was combined with local mesh refinement and geometric smoothing at aggregate-mortar interfaces, thereby constructing a two-dimensional meso-scale analytical model of full-graded dam concrete that accurately captured the micrometer-scale interfacial geometry and mechanical properties. Based on this model, the stress distributions and their evolution within the interfacial transition zone and the mortar matrix were systematically investigated under two autogenous volume deformation modes—shrinkage and expansion—and under different constraint conditions, including single-sided and four-sided constraints. [Results] 1) Different autogenous volume deformation modes governed the spatial distribution characteristics of meso-scale stresses. Under autogenous shrinkage, tensile stresses were concentrated in the cement mortar regions adjacent to sharp aggregate corners because the shrinkage of the mortar matrix was restrained by aggregates, with the local stresses reaching 3.6-4.0 MPa, approaching the tensile strength limit of the mortar. In contrast, under micro-expansion deformation, the restriction of expansion by aggregates caused the tensile stress concentration zones to shift to the specimen surface and the corner regions of internal interfacial transition zones, with a significant increase in the stress concentration factor, indicating that the interfaces became the weak links under expansion conditions. 2) Constraint conditions played a critical role in regulating the stress state of concrete. Compared with a single-sided constraint, the four-sided constraint simulating the strong restraint of a dam foundation significantly amplified the adverse effects of shrinkage deformation, with the shrinkage-induced tensile stresses in the cement mortar generally increasing by 0.8-1.2 MPa, and the local tensile stress at interfaces even exceeding 4.0 MPa, resulting in a sharp increase in cracking risk. Under the same constraint conditions, however, the positive effect of micro-expansion deformation was effectively transformed, causing the concrete as a whole to remain in a compressive stress state and thereby significantly enhancing its cracking resistance. 3) Based on the maximum tensile stress criterion and by comprehensively considering the actual tensile strengths of the mortar and the interfacial transition zone, the safe deformation threshold for high crack-resistant concrete was determined. The autogenous volume deformation of full-graded dam concrete should be strictly controlled within the range of -9×10^-6 to 11×10^-6. In addition, sensitivity analysis further revealed the influence patterns of key parameters. When the elastic modulus ratio between mortar and aggregate varied by ±20%, the elastic moduli of the mortar and aggregate had a significant effect on the maximum tensile stress of the specimen. Therefore, in dam concrete design, attention should be paid to the coordination between the elastic moduli of mortar and aggregates to prevent excessive tensile stresses induced by autogenous or external deformation. Meanwhile, deformation control indices should be dynamically adjusted according to specific constraint conditions. [Conclusion] Adopting a deformation control strategy of “low shrinkage or micro-expansion” and precisely limiting the deformation magnitude within the above threshold range is an effective approach to enhancing the cracking resistance of dam concrete from the perspective of material design. The established meso-scale model and the obtained quantitative conclusions provide direct evidence for performance-based crack resistance design of concrete. They also offer clear guidance for concrete mix proportion design, optimization of expansive agent dosage, and crack control in practical engineering, and provide a reliable analytical approach for in-depth investigation of deformation coordination and cracking evolution mechanisms of dam concrete at the meso-scale.