Detection of In-site and Cause Analysis of Splitting Cracks of Vertical Wall for Large-scale three-direction Pre-stressed Aqueduct

摘要

Splitting cracks were found in the three-directional pre-stressed aqueduct of a large scale diversion project in north China. Based on internal structural characteristics of the vertical wall of aqueduct, the Impact Imaging Method (IIM) was adopted for the detections of cracks distribution, seriousness and damage area ratio of the internal cracks and the damage cause analysis. The core test and numerical simulation by 3D-FEM with prefabricated joints element were also adopted for verifications. The drilled cores showed that the IIM has high accuracy and resolutions on the internal crack distributions. It provides reliable fundamental data for decisions of the wall repair strategies. Both field test results and numerical analysis showed that the frost of the water inside the corrugated pipes that contained the pre-stress tendon led to the internal splitting cracks, which was due to the incompact grouting into the pipes. This accident teaches us the significance for the grouting quality control of the corrugated pipes inside the post-tensioned structures in cold regions of northern China.