Numerical Prediction of Slope Deformation for the Design of an Anchored Railway Embankment
| Project partner | Gesellschaft für Baugeologie und -messtechnik mbH (gbm) |
| Project duration | 23 months, Start 01.2021, End 12.2022 |
| Project execution |
Frederik Brosz, M.Sc.
, Dr.-Ing. Jan Machaček , Prof. Dr.-Ing. Hauke Zachert |
| Contact | Dr.-Ing. Jan Machaček |
Project Background and Objectives
Over several decades, significant time-dependent settlements of the trackbed have been observed along a roughly 200 m section of DB railway located between two tunnels. In this section, the track bed lies on an artificial embankment approximately 50 m high with a slope of about 35-40 degrees. The slope fill consists of material excavated during the tunnel’s construction.
Previous maintenance measures – particularly ballast tamping – proved effective only in the short term. During investigations into various rehabilitation options, a pronounced shear plane was identified as the main cause of the deformations. Preliminary analyses indicated that permanent slope stabilisation using anchors would be the preferred solution. For the detailed design phase, numerical calculations were carried out to predict slope deformations, taking this stabilisation measure into account.
Methodology and Implementation
Based on borehole data, inclinometer and extensometer measurements, geodetic surveys, and deformation data recorded over several years, two key cross-sections were defined for analysis and subsequently examined numerically using the FE software Plaxis 2D.
A material model capable of representing the time-dependent deformations of the rock fill was calibrated using the measurement data. The geometry of the shear plane was iteratively adjusted until good agreement was achieved between measured and predicted settlements. Anchors and anchor plates were then incorporated into the model; prestressing of the anchors was taken into account. Finally, the time-dependent development of slope deformations was simulated.
The results show a clear reduction in predicted deformations compared to an unstabilised slope. Figure 1 shows the FE model of the slope and the comparison between predicted and extrapolated deformation data.
Results and Outlook
The analyses showed that the anchors significantly reduce the time-dependent predicted deformations of the slope compared to an unstabilised slope. The findings were incorporated into the detailed design phase.
