Accurately determining the mechanical parameters of surrounding rock in tunnel design and construction presents a significant challenge due to the complexity of the environment. This study proposes a novel approach for inverting these parameters using an advanced optimization method, the Improved Grey Wolf Optimization (IGWO), integrated with a BP neural network (IGWO-BP). Key enhancements such as cubic chaotic mapping, refraction backward learning, nonlinear convergence factors, and updated position formulas were applied to improve the algorithm’s search efficiency. By optimizing the neural network’s weights and biases, a precise relationship between rock mechanics and displacement was established. The method was validated through a case study of the Lianhua Tunnel (YK37 + 330 section), utilizing field data of crown settlement and peripheral displacement. The approach accurately predicted mechanical parameters, with relative errors below 5.02% for crown settlement and 4.15% for peripheral displacement. These results demonstrate the reliability and practical applicability of the proposed technique for tunnel engineering.

Dredged Fill Soil, as a primary foundation material in reclamation projects, exhibits complex physical and mechanical properties, characterized by a high plasticity index, high water content, low density, high compressibility, large void ratio, and low bearing capacity. Its creep behavior is highly sensitive to temperature changes. This study systematically investigates the temperature-dependent creep behavior of reclaimed soil from Humen Port through laboratory experiments, theoretical modeling, and experimental validation. Triaxial creep tests conducted at different temperatures (5 °C, 15 °C, 25 °C, 35 °C) show that increasing temperature significantly exacerbates creep deformation: under undrained conditions, creep strain at 35 °C is nearly 300% higher than at 5 °C, while drainage reduces the strain by approximately 29.3%. Based on these results, a Burgers-type creep constitutive model considering temperature effects is developed, incorporating the impact of temperature on viscosity and elastic modulus. The model’s predictions show good agreement with the experimental results (15 °C: R² = 0.9788; 35 °C: R² = 0.9890), confirming the model’s validity. The research findings provide theoretical and practical references for the long-term stability evaluation and engineering design of reclaimed foundations in complex marine environments.