Control of Road Settlement around Stone-Arch Bridges by Material Modification and Embankment

Occurrence of road settlement around bridges is considered as one of the common problems of road operations. In buried bridges, especially in deep valleys, where it is not possible to use soil compaction machinery, significant settlement is observed after road operation. Such settlement mainly reduces the ride quality as well as the safety of the crossing. Based on experience, the deeper the valley and the weaker the soil, the greater the settlement created in these embankments. In this paper, in addition to field assessment of settlement in buried bridges, a suitable method has been presented for embankment around these bridges. In this regard, by finite element method, a sample of bridges buried in deep valleys has been modeled in which the settlement was calculated. The results of the finite element method were compared with the field values of the settlement at one of the studied bridges. The results showed that the settlement was directly related to the width and depth of the valley, the volume of the embankment and the soil type. Also, the results of numerical studies by finite element method showed that the created settlement was strongly affected by the modulus of elasticity of the soil compared to other parameters. If the modulus of elasticity of the materials reduces, the settlement will increase significantly. In this study, a suitable method for embankment around buried bridges in deep valleys has been presented. The results of using this method showed a significant reduction in settlement around buried bridges.