Objective: During a rocket launch, the rocket barrel generates a strong impact load on the runway, and the load-bearing performance of the runway needs to meet specific requirements. The most critical control indicator of this performance is the runway settlement value at the impact center. Earlier launch test data revealed that, if the runway settlement at the impact center can be controlled within 0.070 m, its impact on launch will be negligible. Accurately predicting the load-bearing performance of the runway pavement and selecting a launch pavement that meets the requirements have become prominent issues that need to be solved. Hence, studying the load-bearing capacity of the pavement under impact loads is of great significance. Methods: Existing analyses of the pavement impact dynamic response are mostly based on elastic or elastoplastic layered systems, focusing on the surface and base layers and simplifying the soil foundation as an elastic medium. However, one of the most important factors causing the settlement and deformation of a site is the insufficient bearing capacity of its soil foundation. The reasona[KG-0.15mm]b[KG-0.1mm]le selection of the basic soil structure model and the sensitivity analysis of parameters are important in evaluating the feasibility of unsupported launch. This article proposes an accurate nonlinear numerical simulation model to study the settlement deformation law of pavement under impact loads, conducts sensitivity analysis of key parameters, identifies key factors controlling site deformation, provides key control indicators for site selection, proposes targeted pavement strengthening schemes, and conducts numerical verification. Results: This study explored the deformation behavior and bearing capacity of two typical low-grade pavements, namely cement concrete pavement and asphalt concrete pavement, under impact loads. The following four conclusions were drawn from this study. First, the most important factor affecting the settlement of the impact center was the strength of the soil foundation, and this settlement was mainly caused by the settlement deformation of the soil foundation. The settlement deformations of the surface and base layers had little effect. Second, for cement concrete pavement, a surface layer thickness of 15 cm, a base layer thickness of 20 cm, and a soil foundation rebound modulus of over 30 MPa could meet the impact settlement requirements. For soil foundations with a rebound modulus below 25 MPa, the settlement requirements could not be met. Third, for asphalt concrete pavement, a surface layer thickness of 7 cm, a base layer thickness of 20 cm, and a soil foundation rebound modulus of 35 MPa or above could meet the impact settlement requirements. For soil foundations with a rebound modulus below 30 MPa, the settlement requirements could not be met. Finally, the simple steel pad reinforcement effect in the pavement strengthening scheme was limited. Improving the stiffness of the steel pad itself was the key to controlling the impact settlement. The reinforcement effect of the 10 cm thick empty box lattice steel pad was ideal, which could significantly reduce the impact settlement. Conclusions: Regardless of regional differences, the soil foundation rebound modulus of domestic medium and high-grade pavements can generally reach 30 MPa. Even if there is a soft foundation, necessary foundation treatment measures are usually taken in the design stage to control post-construction settlement. Considering that after years of operation, the roadbed will be further consolidated and compacted, the soil foundation rebound modulus will subsequently increase. Therefore, medium and high-grade pavements can meet the requirements of an impact load. Attention should be given to the situation of a soft foundation under the surface "hard shell" of a low-grade pavement, which needs to be confirmed through site investigation and testing (such as geophysical exploration). In case of an emergency launch, a steel pad reinforcement plan should be supplemented to ensure safety.