Experimental Study on Vacuum Dehydration of Waste Silty Clay Slurry in Shield Tunneling

doi:10.12141/j.issn.1000-565X.230736

Abstract

Abstract:

The waste silty clay slurry produced during shield construction has the characteristics of high water content, low strength and small particle size and it has difficulties in rapid consolidation. How to effectively dehydrate and cure is the key to reduce environmental pollution in the process of transportation or storage. Based on the self-developed waste slurry vacuum dehydration device, this study carried out indoor dehydration model tests under four different forms of dead weight, dead weight and vacuum, dead weight stabilization and vacuum, dead weight stabilization and graded vacuum. It analyzed the distribution laws of sediment-water interface settlement, pore water pressure, dehydration volume and residual slurry moisture content after dehydration of waste silty clay slurry under different loading modes. Finally, the dewatering effect of the waste silty clay slurry was compared under different loading modes. The test results show that among the four dewatering methods, the loading method of first dewatering the waste silty clay slurry by self weight, and then applying vacuum to the bottom part of the waste silty clay slurry has the best dewatering effect on the waste silty clay slurry, which can effectively reduce the water content of the waste silty clay slurry. After dewatering the waste silty clay slurry with initial water content of 97.50%, the water content distribution range is 28.21%~34.25%, and the minimum pore water pressure can reach -72.92 kPa. Meanwhile, based on the idea of segmented linearization, a one-dimensional dehydration theoretical analysis model for waste slurry was established. This model numerically simulates the sedimentation of the sediment-water interface during the dehydration process of waste silty clay slurry, and compares the results of numerical simulation with the test results. Then the optimal loading method was explored by simulation analysis of dehydration efficiency under different loading modes. This study can provide a theoretical and practical basis for the rapid dehydration treatment of shield waste silty clay slurry.

Key words: waste silty clay slurry, vacuum dehydration, segmental linearization, pore water pressure, settlement, water content

CLC Number:

TU44

GAO Xinjun, WANG Jianbo, SU Qinghui, et al. Experimental Study on Vacuum Dehydration of Waste Silty Clay Slurry in Shield Tunneling[J]. Journal of South China University of Technology(Natural Science Edition), 2024, 52(11): 69-82.

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试验编号	泥浆高度/cm	脱水工况
B1	60	自重
B2	60	自重+真空
B3	60	自重稳定+真空
B4	60	自重稳定+分级真空

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