Experimental and Theoretical Study on Vacuum Dewatering of Waste Shield Clay Slurry

Abstract:

To address issues such as slag dumping and limited slag transportation under the action of upper vacuum dewatering， a dewatering method of applying a vacuum load at the bottom of the waste slurry is proposed. A series of model tests were conducted on waste clay slurry under four different dewatering loading conditions by using a self-developed dewatering device that can apply a vacuum load at the bottom of the waste slurry. The rule of physical quantities such as settlement at the interface between slurry and water， pore water pressure， water content， and the total amount of water discharged after dewatering are analyzed. The results show that the fourth dewatering loading method has the best dewatering performance. After the fourth dewatering loading method was used to dewater the waste clay slurry with an initial water content of 103.00%， the water content distribution range was 37.10%?62.65%， and the minimum internal pore water pressure was -73.09 kPa， which was close to the vacuum value of -80.00 kPa applied at the bottom. In addition， compared with the other three dewatering loading methods， the average settlement was increased by 106.40%， 2.91%， and 6.15%， respectively， and the total amount of dewatered water increased by 122.0%， 8.0%， and 5.1%， respectively. Meanwhile， a numerical calculation model for vacuum dewatering of waste clay slurry is provided based on piecewise-linear finite difference CS2 model. The sedimentation at the slurry-water interface during the dewatering process of waste clay slurry was numerically simulated， and the effectiveness of the numerical calculation model was verified.