Study on the influence of expansive soil slope on bridge foundation under excavation and rainfall conditions

Abstract

Abstract Expansive soil is a kind of special soil that mainly composes of hydrophilic minerals and has significant deformation characteristics of water absorption expansion and water loss shrinkage. The characteristics often bring great harms to engineering construction. Relying on the bridge foundation on the expansive soil slope of the Yangtze‐to‐Huaihe Water Diversion Project, this study simulates the humidity field with temperature field for expansive soil using the numerical simulation method when short‐term or long‐term rainfall occurs during slope excavation. The horizontal deformation of bridge foundation on expansive soil slope considering four factors such as self‐weight of slope soil, excavation unloading rebound, hygroscopic expansion of expansive soil, and decrease of soil strength caused by change of water content was studied herein. The research results show that during the excavation process, the bridge foundation produces a horizontal displacement towards the top of the slope, and the rainfall after excavation introduces a decrease to the horizontal displacement of the bridge foundation and gradually develops in the opposite direction. During the excavation process, the rebound of slope excavation is the main factor affecting the horizontal displacement of the bridge foundation. Under short‐term rainfall conditions, the hygroscopic expansion of the slope soil becomes the main influencing factor. Under long‐term rainfall conditions, the main influencing factors of horizontal deformation of bridge foundation are the self‐weight of slope soil and the decrease of soil's strength.

Keywords

• bridge foundation
• excavation
• expansive soil slope
• rainfall