IN-SITU INVESTIGATION ON CAUSES OF ROAD SURFACE SINKING AT HAITAI DISTRICT OF TIANJIN HI-TECH INDUSTRIAL PARK

Road surface sinking is a serious hidden risk for safety travelling in city. There is a close relation among road surface sinking, underground cave and sewage pipe linkage in Haitai District of Tianjin Hi-tech Industrial Park. In this paper, a generation mechanism of road surface sinking is studied through site investigation, geological radar detection, pipeline robot endoscopic detection technology, engineering drilling and 3-dimensional geological modeling. Through study, it is proven that the generation mechanism is representative and typical in coastal area. The weak nature(geological) system interacts with artificial(engineering) system under complex control of multiple factors. The pipeline is buried in safe soil. Its lateral and vertical immigration can occur due to natural settlement and compaction. It can cause crack and damage to sewage pipes at the joints, which further makes the underground water above the pipeline leaking into the pipeline. Then caves are formed due to loss of particles of soil. It finally leads to road surface sinking. Accordingly, treatment measures before burying pipeline and after occurrence of road surface sinking are proposed respectively. The focus is to prevent exchange of underground water and sewage water in the pipeline due to damage of pipeline and to avoid loss of soil particles surrounding the pipeline.