• Investigating the settlement of high embankments under HSR train loads. • Applying an advanced simulation model by Plaxis API with Python remote scripting. • Developing a reliable settlement estimation using the GEP algorithm. • Optimising the design of the GRPS system with geocell reinforcement. The construction of high-speed railway (HSR) embankments on soft ground areas is a geotechnical challenge due to excessive settlement and long-term deformation. Thus, this study evaluates the effectiveness of deep cement mixing (DCM) piles reinforced by a geocell system (GPRS) as a ground improvement method. An advanced automated simulation framework using Python remote scripting was developed to examine the effects of train load, embankment height, soft soil thickness, and the number of geocell layers. Approximately 336 data points on the settlement of the HSR embankment was extracted from Plaxis analysis. The highest equivalent train load was 100 kN/m 2 and the settlement of the embankment fluctuated from 22 to 65 mm. A Gene Expression Programming (GEP) algorithm was then applied to develop a reliable regression among the key variables with high accuracy (R = 0.99) and low errors. The parametric study indicated that the geocell reinforcement could significantly improve the lateral resistances, mobilise the membrane effect within the fill material, and reduce vertical stress and cumulative settlement. The research findings provide critical insights for improving the design process, optimising GRPS reinforcement using geocell, and enhancing predictive capabilities for HSR embankment settlement under various ground conditions.

Abrasive erosion induced by a mixture of fluid flow and fine particles is a typical type of bridge damage in the high mountain region of Southwest China. In this study, a field survey of abrasion damage to the Duxiufeng Bridge is carried out to investigate the practical abrasion damage state of two adjacent cylindrical concrete piers and their distribution. The rear surface of the bridge pier also experiences severe abrasion damage, which is often overlooked in single pier cases. Then, numerical models are built to investigate the abrasion damage, where the particles are modeled with discrete phase models. Cases with a single bridge pier and two adjacent cylindrical piers are used for analysis. The results indicate that the abrasion damage increases with the position varying from the middle of the front surface to the lateral sides of the circular cross section. This abrasion damage pattern is directly related to the flow velocity, which describes the energy distribution with the uniform fine particle size assumption. Diffraction and vortex shedding effects cause rear surface erosion. The damage state increases when there is an adjacent downstream bridge pier. The downstream bridge pier has a limited impact on the abrasion damage of the upstream pier on the front and side surfaces. Owing to the sheltering effect, the abrasion damage is significantly mitigated for the downstream bridge pier.