Numerical investigation on replacement depth of black cotton soil for controlling cracking of highway embankment

Abstract

The replacement depth of black cotton soil (BCS) was investigated to control the cracking of the highway embankment. With the help of the user subroutines Abaqus, the FEM model of the highway embankment on BCS was constructed. The change of major principal stress within the highway embankment due to the water losing shrinkage of BCS was simulated. The results indicate the tensile stress caused by shrinkage of BCS extends gradually to the inner side of the embankment along the slope surface, finally reaches the threshold and results in the cracking of highway embankment. There is a critical value of BCS depth and its replacement depth, respectively. Beyond this value, the cracking of embankment is mainly controlled by the shrinkage of BCS outside the subgrade. The weight of earth filling can restrain the embankment cracking caused by shrinkage of BCS. To control the cracking of high-filled highway embankment on deep BCS, the top 1.2 m of BCS should be replaced. For low-filled highway embankment, the replacement depth of shallow BCS should be greater than 0.8 m, while that of deep BCS should not be less than 1.2 m, moreover, measures such as slope protection should also be used.

Keywords:

• Black cotton soil
• water losing shrinkage
• stress distribution
• embankment cracking
• replacement depth

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the [Jiangsu Planned Projects for Postdoctoral Research Funds] under Grant [number 2020Z422], [the Open Fund of Guangxi Key Laboratory of Road Structure and Materials] under Grant [number 2019gxjgclkf003], [Huai'an Natural Science Research Program] under Grant [number HABZ201915].