Research and Application of Over-filling Monitoring Technology for Underwater Cast-in-place Piles

Abstract

The quality of the pile head is the construction controlling difficulty of the concrete cast-in-place pile technology when the bored piles, especially the deep foundation piles, are filled with underwater concrete. The hammer method and volume estimation method are widely used to control concrete over filling in the prior technology. However, in the actual operation, these two methods are inclined to cause misjudgment by the field technicians, so it is difficult to accurately determine the height of the concrete, resulting in the under or over height of the pile head, which seriously affect the construction quality and greatly increase engineering costs in construction sites. In order to solve this problem, based on the principle that the mud density of the bored pile and the concrete density are different, and the pressure difference is generated at a certain depth, in this paper a liquid pressure sensor, da-ta acquisition module, wireless communication module, remote network server and monitoring terminal were used to develop an overfilling control-ling device for underwater concrete bored piles. Several engineering field tests were carried out and the test results showed that the device could accurately monitor the timing when concrete reaches the designed pile top elevation position and the specific quantitative height in the underwater pouring process, and can alarm after exceeding the limit as while. The method is simple and practical, and has high promotion value.