Pilot tests on methods to form working platform on soft clay

Pilot tests on the usage of vacuum preloading combined with short prefabricated vertical drains (PVDs) to form a working platform for future soil improvement work were conducted at a land reclamation site in Tianjin, China. The short PVDs were connected using three methods – the conventional vacuum preloading method, fish-bone connectors and embedded horizontal pipes. To investigate the influence of PVD spacing, short PVDs were installed in square grids with spacings of 0·4 m and 0·6 m. The ground surface settlement, pore water pressures, water content and undrained shear strength of the soil were measured during the specific period of vacuum preloading. The pilot tests indicated that short PVDs connected using embedded vacuum pipes installed at 0·4 m spacing were the most suitable method to form a working platform on the surface of the dredged marine clay. This method yields a substantial saving on construction cost and time while exhibiting similar efficiency to the conventional vacuum preloading method...

[1]  John P. Carter,et al.  Ground Deformation Induced by Vacuum Consolidation , 2005 .

[2]  Thiam-Soon Tan,et al.  Hyperbolic method for consolidation analysis , 1991 .

[3]  Siewann Tan.  Validation of hyperbolic method for settlement in clays with vertical drains , 1995 .

[4]  Siew-Ann Tan,et al.  Comparison of the Hyperbolic and Asaoka Observational Method of Monitoring Consolidation with Vertical Drains. , 1996 .

[5]  Buddhima Indraratna,et al.  Performance and Prediction of Vacuum Combined Surcharge Consolidation at Port of Brisbane , 2011 .

[6]  Buddhima Indraratna,et al.  Vacuum Preloading Techniques - Recent Developments and Applications , 2008 .

[7]  Jian Chu,et al.  Soil improvement by the vacuum preloading method for an oil storage station , 2000 .

[8]  Robert D. Holtz,et al.  Prefabricated vertical drains (PVDs) in soft Bangkok clay: a case study of the new Bangkok International Airport project , 2002 .

[9]  Jian Chu,et al.  Consolidation of cement-treated sewage sludge using vertical drains , 2005 .

[10]  A. Kumar,et al.  Enhancement of efficiency of prefabricated vertical drains using surcharge, vacuum and heat preloading , 2011 .

[11]  Hamid Nikraz,et al.  Instrumentation at Changi land reclamation project, Singapore , 2009 .

[12]  Arul Arulrajah,et al.  Reclamation of a slurry pond in Singapore , 2009 .

[13]  Akira Asaoka,et al.  OBSERVATIONAL PROCEDURE OF SETTLEMENT PREDICTION , 1978 .

[14]  Jian Chu,et al.  Soil improvement for a storage yard using the combined vacuum and fill preloading method , 2005 .

[15]  Arul Arulrajah,et al.  Soil improvement works for an offshore land reclamation , 2009 .

[16]  Masaaki Terashi,et al.  Chapter 4 Key Issues in the application of vertical drains to a sea reclamation by extremely soft clay slurry , 2005 .

[17]  Bengt B. Brons.  Stabilization of very soft clay using geofabric , 1987 .