The Application of Non-destructive Detection Technology for Hidden Leakage in the Enclosure with Electric Field in a Deep Excavation Project in Shanghai, China

The hidden leakage of enclosure is a major risk source of deep excavation projects, and there is no effective method to detect the leakage at present. This paper introduces a non-destructive detection technology based on electric field for hidden leakage of enclosure in deep excavation projects by analyzing the distribution of electric field inside the foundation pit. The later excavation of a deep excavation project in Shanghai verifies that the detection results is convincing, which confirms that this method can accurately identify the hidden leakage in the foundation pit before excavation. And this method is applicable to various types of in-situ walls used to support excavations, including diaphragm walls, deep mixed walls, reinforced concrete retaining walls, etc. It is able to rapidly, accurately pre-detect the hidden leakage of the retaining structure, and provides early warning of leakage in enclosure. Therefore, the strong technical support for reinforcing the foundation pit is also proposed after detection.