深圳湾海底淤泥大变形固结试验研究

深圳湾海底淤泥含水量很高,在外加荷载作用下,其固结压缩过程具有明显的大变形特征。选取深圳湾西部通道口岸处海水下3 m海底淤泥制作土样,对重塑土样进行固结及渗透交叉试验。通过测定土样的孔压、压缩变形以及渗透过程中的排水量,研究深圳湾海底淤泥的体积压缩系数、大变形固结系数的变化规律。研究结果表明:深圳海底淤泥的大变形固结系数在常用荷载内变化不大,设计估算时可作为常数,而体积压缩系数在固结过程中随孔隙比的变化较大,如假定其为常量采用简化的解析求解,会使得出的结果误差较大,甚至大于采用Terzaghi固结理论计算的偏差。

Large Strain Consolidation Test on the Marine Clay of Shenzhen Bay

The natural water content of the marine clay in Shenzhen Bay is very high.The compression and consolidation of the marine clay under additional load feature obviously with large strain consolidation.Soil samples,collected from the port of Shenzhen-Hongkong Western Corridor under seawater at about 3 m depth,were remoulded to carry out the consolidation and permeability cross test.During the test,the pore pressure,compressive displacement,and volume of water drained out from the samples were measured,the development regularity of the volume compression parameter and the coefficient of large strain consolidation were estimated.Results show that the large strain consolidation coefficient g of Shenzhen marine clay changed very little within conventional loading,which can be regarded as a constant in the design estimation.While the volume compression coefficient mv changed greatly with the void ratio during the consolidation process.If the mv is presumed as a constant in simplified analytic solution,the errors of the results calculated by large strain consolidation theory would be very great,even greater than those calculated by Terzaghi consolidation theory.