The site is located in Sacramento County along both banks of the American River. The project involved the construction of several cutoff walls under the embankments, with a minimum thickness of 3ft [0.9m] and an overall length of about 820yd [750m], in order to integrate the existing waterproofing works to reduce filtration phenomena.
2002 | 2003
The project included slurry walls diaphragms where possible, integrated with jet grout treatments in the most problematic areas (presence of sub-services, road and railway intersections, limited headroom conditions) with the aim of creating a 3ft [0.9m] thick cutoff wall inside and below the levees.
The work was carried out both in lithologically homogeneous as well as very diversified sections. The deposits involved in the works consisted mainly of sand, clay and silt with sporadic accumulations of gravel and pebbles at depths greater than 55ft [17m].
A particular feature was the construction of a very extensive test field which, compared to a work that involved the execution of not many columns, involved the construction of as many as 85 Jet Grout elements including columns, panels and circular sectors. This is because the client wanted to investigate multiple aspects before choosing the best methodology and geometry for the project. The method chosen for the work was the Pacchiosi Jet Grouting Triple System (PS3).
All Jet Grouting treatments were installed using a triple-fluid technology (air, water and grout), using a bottom-up installation procedure. Complete works has required approximately 120 PS3 Jet Grouting columns -also inclined- with a diameter of 8.25ft [2.5m] and 20ft [6m] extended thin panels, with drilling about a depth of 100ft [30m].
Continuous monitoring of Jet Grouting parameters using PRS3 real time data collection system and vertical measurement at each grout element were provided during field trial and production work on the levees.
