Analysis of Settlement Behaviour of Soft Ground Under Wide Embankment

Xin Jiang,Jinming Hu,Yanjun Qiu,Xiaoli Chen,Hanyan Gu,Xing Qiu,Yongguo Fu

doi:10.7250/bjrbe.2021-16.543

Xin Jiang, Jinming Hu + Show 5 more

Open Access

https://doi.org/10.7250/bjrbe.2021-16.543

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Abstract

An elastoplastic numerical model for calculating the consolidation settlement of wide embankment on soft ground is established using PLAXIS finite element software to investigate the settlement behaviour of soft ground under the wide embankment. The distribution rules are analysed and compared to narrow embankments, such as surface settlements of ground and embankment, lateral displacement of soft ground at the foot of embankment slope and excess pore pressure in soft ground. The influence rule of elastic modulus of soft ground on the settlement of soft ground under wide embankment is discussed. The results show that the settlement distributions of wide and narrow embankments on soft ground are “W” and “V” shapes, respectively. The maximum settlement of wide embankment is near the foot of the embankment slope, which is unequal to the settlement at the centreline of the embankment. The lateral displacement distribution rules of soft ground are both “belly” shaped at the foot of two types of embankments slope. However, the lateral displacement of the wide embankment is larger in each corresponding stage. During the construction period, the excess pore pressure in the soft ground under the wide embankment is much higher than that of the narrow embankment, so the post-construction consolidation time of the wide embankment is longer. Moreover, the macroscopic settlement rule of the wide embankment is still the same with the increase of elastic modulus of soft ground.

Highlights

With the rapid economic development of many countries, the traffic volume increases rapidly
The results show that the settlement distributions of wide and narrow embankments on soft ground are “W” and “V” shapes, respectively
The expressways with eight lanes or even above ten lanes have become more popular to meet the demand of increasing traffic volume

Summary

Introduction

With the rapid economic development of many countries, the traffic volume increases rapidly. The expressways with eight lanes or even above ten lanes have become more popular to meet the demand of increasing traffic volume. Two ways are adopted to build a wide embankment, i.e., one way is to widen the existing narrow embankment (Allersma et al, 1994; Lu et al, 2020). The theoretical research is relatively mature, especially in ground improvements for reducing differential settlement between new and existing embankment, including gapmethod (Van Meurs et al, 1999), foundation columns (Han et al, 2007), prefabricated vertical drains (PVD) and dry jet mixing (DJM) columns (Jiang et al, 2020). The new wide embankment has no restraint and influence from the adjacent existing embankment, so the settlement characteristics are different from that of the widened embankment (Jiang et al, 2015)

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Discussion

Conclusion