A Large-Strain Vacuum-Assisted Radial Consolidation Model for Dredged Sludge Considering Lateral Deformation
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pISSN 1226-7988, eISSN 1976-3808 www.springer.com/12205
DOI 10.1007/s12205-020-1854-8
Geotechnical Engineering
A Large-Strain Vacuum-Assisted Radial Consolidation Model for Dredged Sludge Considering Lateral Deformation Yupeng Cao
a
, Jing Zhang
b
, Jianwen Xu
b
, and Guizhong Xu
c
a
College of Civil Engineering and Architecture, Weifang University, Weifang 261061, China College of Transportation, Shandong University of Science and Technology, Qingdao 266590, China c Geotechnical Research Institute, Yancheng Institute of Technology, Yancheng 224051, China b
ARTICLE HISTORY
ABSTRACT
Received 15 October 2019 Accepted 15 March 2020 Published Online 1 October 2020
A calculation model has been developed for large-strain radial consolidation incorporating lateral deformation in order to solve the problem of poor consolidation prediction for dredged sludge at high water content in vacuum preloading process. The differential solution for the proposed model is given, considering the effect of initial water content on the compression behavior. The model is suitable for unconsolidated soil and normally consolidated soil, which can take into account such factors as lateral deformation, varying compressibility and permeability coefficients, smearing effect, self-weight stress, negative pressure attenuation along the depth, etc. The proposed model is verified by comparing it with other existing theoretical solutions. Poisson's ratio (v) is used to reflect the influence of lateral deformation on soil consolidation. The results show that lateral deformation has an important influence on soil consolidation degree, especially on consolidation degree defined by stress (Up). The consolidation rate increases with the increase of v. The traditional equal-strain solution overestimates the consolidation rate of foundation. At the same normalized elevation, the void ratio increases while the excess pore water pressure decreases with the increase of v.
KEYWORDS Vertical drain Large-strain Consolidation degree Vacuum preloading Dredged sludge
1. Introduction Hundreds of millions of cubic meters of dredged sludge is produced every year in China with dredging projects in ports, waterways, rivers and lakes (Xu et al., 2015; Bian et al., 2018). It is often stored in cofferdams near the sea or beside rivers and lakes to form ultra-soft foundation with high water content. Due to the adoption of cutter and suction dredging method, the dredged sludge has the engineering characteristics of high compressibility, low permeability and low bearing capacity. Normally, the clay particle accumulated around certain area of mud cofferdams, with predominated clay mineral such as illite, smectite, kaolinite (Bian et al., 2020), resulting in poor engineering characteristic for further usage. The foundation formed by the mud need to be reinforced before construction, so as to facilitate the entry of large machinery, reduce uneven settlement, and improve the long-term stability of the structure (Geng and Yu, 2017). The vertical drains combined wi
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