This paper presents a review of literature related to the vacuum consolidation ground improvement technique, focusing on issues affecting efficiency of performance and the application of the technique in peaty ground.Although it is now widely considered to be effective for reducing post-construction settlement, studies on vacuum consolidation in peat have, to date, mostly been limited to field trials. This paper offers an overview of the development and theory behind the technique. Issues affecting the efficiency of vacuum systems and recent advances in predicting the ground response to vacuum preloading are described. The application of the technique in peaty soils is investigated; an overview is also provided of some geotechnical properties that distinguish peat from soft mineral soils, highlighting lessons learned from relevant case studies.

ABSTRACT:This paper presents a review of combined vacuum consolidation and surcharge preloading which is arguably more sustainable approach to soft-soil ground improvement than other strategies in reducing post-construction settlements. Vacuum consolidation has become more prevalent with technological developments in vertical drains, pumps and geosynthetics. Satisfactory vacuum pressures can be sustained at greater depths and for longer periods than in the recent past. Soft soil deposits may experience different issues depending on whether vacuum or surcharge preloading is employed. Surcharging alone may lead to outward lateral deformations and shear failure whereas vacuum alone induces inward lateral deformations, producing crack formation along the boundaries of the treatment area. By balancing these two approaches, respective outward and inward ground movements can be minimised.

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