ABSTRACT
Of all forms of ground improvement systems, jet grouting must be regarded as one of the most versatile. With this technique it is possible to strengthen, cut-off groundwater and provide structural rigidity with a single application. It can also be regarded as one of the most technically demanding of ground improvement systems requiring equally both technical excellence in design and construction because failure of either component will result in failure of the product. Figure 5.1 shows the principle method of application whereby either
high-pressure water or grout is used to physically disrupt the ground, in the process modifying it and thereby improving it. In normal operation the drill string is advanced to the required depth and then the high-pressure water or grout is introduced while withdrawing the rods. As discussed below in Section 5.2, jet grouting has a considerable history
of development from its initial use to current practice. In the field of jet grouting, the most notable advancements have been in Japan where the technique has been refined to its present day capability by careful attention to detail in all aspects of the system. Through the years, careful research and execution has resulted in increasing column diameter and range of applicable soils. This development is set out also in Section 5.2. Within this chapter it is hoped that the practicing engineer will under-
stand how jet grouting came into existence, the technical complexity and design requirements needed for a successful application and indeed the range of applications that jet grouting can be put to. Reference should also be made to the contents of the chapter on jet grouting
in the first edition of Ground Improvement for further reading and in particular details of column layouts typically adopted which is not repeated here.
