Notwithstanding the multiple denominations given by the specialized companies to the methods of application of this technology, the basic systems, even to day, continue being the same two that have been invented, quite simultaneously,in Japan:

· The "CCP" system, or "Chemical Churning Pile", by Nakanishi of the Nissan Freeze Co.

· The "CJG" system, or "Column Jet Grout", better known as the "KAJIMA" method, by Yahiro of the Kajima Corp. Both systems, on the occasion of its participation to the international competition of methods for the stabilization of the Pisa's Tower - the CCP having been awarded with one of three prizes allowed - became known by

italian construction Companies, but they did not pay much attention to it, except one of them that at the moment understood their great importance. It was the "Ettore Colla & Sons" Company of Parma, that immediately (1974) established with Mr. Nakanishi a license agreement related to the CCP system, the reason of being of the former "CCP-Italia" and the present "CCP International" Company. Other italian Companies, only within the decade of `80, made similar agreement related with the Kajima system. It has been the "CCP - Italia" Company the one that first (1974/1979) gave to the system a strong impulse and development, both in equipment - specially by introducing the high pressure pumps for cement grout to conveniently obtain good size columns and also in an ample program of in-situ trials and tests and and of laboratory investigations, with the

specific purpose of acquiring the knowledge, as good as possible, of the interaction the specific purpose of acquiring the knowledge, as good as possible, of the interaction between the techniques of the method and the many different cases of soil context. Early in 1980 the "CCP Italy" decided to share its JG patents' rights with a new company (NOVATECNA) just established in Brazil and tunnelling specialists, and, therefore, to transfer to them all the know-how acquired up to that moment. During these 18 years, NOVATECNA, taking advantage of the multiple, diversified cases of application offered by the extense country along with a wide range of soils to deal with, had the uncommon opportunity of further

developing the technology by always facing the several, progressively complexes and even daring interventions at sound geological-geotechnical and engineering level, often with the support of highly qualified Consultants. , Within this period NOVATECNA operated not only in Brazil, but also in U.S.A., Argentina, Uruguay and Venezuela trough associated companies and, since 1994, also in Portugal trough NOVATECNA EUROPA LTD. that presently turned into the portuguese company NOVATECNA PORTUGAL. Meanwhile, the former "CCP Italy" turned into "CCP International" and while gradually slowing down the application works, it became specialized in jet grouting equipments, particularly in the high pressure pumping groups, the authomatic grout mixing units as well as the jet grouting operation's recording computers.

· The CCP system (that, at the beginning, in Japan, used to jet chemical grouts - from whence arises its name - and only later-on it started with water-cement grout) attacks the soil directly with a violent cement grout jet, produced by a the high pressure upstream of the nozzle.

· The CCP system uses a single steel tube bar trough which the fluid circulates.

· The KAJIMA system attacks the soil with a violent air-coated water jet, impulsed by a water pressure in the range of 50 MPa, that has an increased efficacy because the air coating diminishes the soil turbulence effects over the liquid jet. Simultaneously, by means of a nozzle located 10 to 15 cm

below of the nozzle of the air-water jets, a water-cement grout is jetted out by an internal pressure that - in the standard practise - ranges between 2 and 6 MPa. This grout jet mixes with the particles of soil inside the cylindrical volume just cut and rarefied by the upper air-coated water jet.

· The KAJIMA system uses a bar composed by three concentric steel tubes: the outer for the air, the intermediate for water and the inner one for the water-cement grout.

· Diameters of typical CCP columns used to be 0.8 - 1.0 meter in sand and 0.50 - 0.70 meter in clay. Recent experiences with more advanced parameters and ultra powered pumps,showed columns' diameters of 1.5 - 2.0 meters in sandy-silty-clay. Anyway, the upper limits of the diameter in any case attainable are defined mainly by the available equipments and correlated economic conditions more than by technical limitations.

· Typical Kajima columns may reach diameters of 1.5 - 2.0 meters in clay and of 2 to 3 meters in sand. Yet, this system has the inconvenience that the great quantity of water used to obtain such dimensions removes outwards a great portion of the fine particles of the soil. Based on his CCP system,

Mr. Wataru Nakanishi developed two other techniques, of which for this document only the following-one is significant:

· The "JUMBO GROUT", in which the violent water-cement jet that attacks the soil is now coated - as the water jet of the Kajima system - by an outer coaxial jet of compressed air, so considerably increasing the effective range of the grouting jet.

· The Jumbo Grout system uses a bar composed by two concentric steel tubes: the outer for the air and the inner one for the water-cement grout.

· Typical Jumbo Grout columns' diameters used to be 1.2 up to 2.0

meters, but, in very recent experiences with advanced parameters, columns with diameters exceeding 3m in granular soils and up to 2,8 m in clay were obtained.