Ground improvement refers all techniques employed in the engineering of soil to achieve the desired properties. It has become a major branch in civil engineering over the last few decades, and their use is growing rapidly. At present there are numerous techniques applied to treat various types of soils such as compaction, grouting and use of geosynthetics. For our thesis, we are doing a research on the ground improvement technique by jet grouting.
Jet grouting is a procedure of mix-in-place. It involves the controlled erosion of soil particles using high-pressured erosive jets of grout or water. These eroded soils become mixed with the grout to form treated mass or elements, which maybe of the shape of column, plane or wings. Interlocking of these individual elements are used to form jet grouted structures to achieve the desired stability or permeability. Jet grouting can be carried out on any type of soil independent of the grain size and permeability, with the exception of soils with large number of cobbles and hard cohesive soil whose strength cannot be overcome by the jet. It is can also be use to treat stratified soil. Simple cementitious grouts are used exclusively in jet grouting. Bentonite and other form of admixture are sometimes added to improve properties.
Jet grouting has been widely used in several fields of civil engineering, which includes earth retaining and foundation works, slope stabilisation, ground water control, waste deposits sealing, tunnelling and underpinning of buildings. Case studies of jet grouting projects in Italy and New Haven, USA have been done, to look into the process, construction and quality control of successful jet grouting process.