Techno Press
Techno Press

Geomechanics and Engineering   Volume 1, Number 3, September 2009, pages 179-191
DOI: http://dx.doi.org/10.12989/gae.2009.1.3.179
 
Optimum PVD installation depth for two-way drainage deposit
J.-C. Chai, N. Miura, T. Kirekawa and T. Hino

 
Abstract     [Full Text]
    For a two-way drainage deposit under a surcharge load, it is possible to leave a layer adjacent to the bottom drainage boundary without prefabricated vertical drain (PVD) improvement and achieve approximately the same degree of consolidation as a fully penetrated case. This depth is designated as an optimum PVD installation depth. Further, for a two-way drainage deposit under vacuum pressure, if the PVDs are fully penetrated through the deposit, the vacuum pressure will leak through the bottom drainage boundary. In this case, the PVDs have to be partially penetrated, and there is an optimum installation depth. The equations for calculating these optimum installation depths are presented, and the usefulness of the equations is studied by using finite element analysis as well as laboratory model test results.
 
Key Words
    prefabricated vertical drain (PVD); ground improvement; vacuum consolidation; laboratory test; pre-loading; soft clayey deposit.
 
Address
J.-C. Chai: Department of Civil Engineering, Saga University, 1 Honjo, Saga 840-8502, Japan
N. Miura: Institute of Soft Ground Engineering, Co., Ltd., 4-1-52 Ohtakara, Saga 840-0811, Japan
T. Kirekawa: Institute of Soft Ground Engineering, Co., Ltd., 4-1-52 Ohtakara, Saga 840-0811, Japan
T. Hino: Institute of Lowland Technology, Saga University, 1 Honjo, Saga 840-8502, Japan
 

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