Effects of jet grouting on the performance of braced retaining wall

Abstract

This project studies and reports on the performance and behavior of braced excavation under

the presence of jet grout piles. Two-dimensional analyses were carried out with the help of

finite element software PLAXIS 2D.

The analyses were carried out for a 20 m deep excavation in clay supported by a 26 m long

wall. A total of 108 different cases were considered where the presence and thickness of the

jet grout piles were varied. Varying excavation widths, wall stiffness and clay undrained

shear strength were also considered. Comparisons of the retaining wall deflections, wall

bending moments, strut forces, basal heave safety factor and plastic points patterns were

carried out.

In general, jet grouting performs more effectively in low strength soil compared to high

strength soil. Results indicate that the presence of jet grout effectively reduces the wall

deflection especially for retaining walls with lower stiffness. Strut forces on the other hand

are more effectively reduced for struts closer to the formation level than struts close to the

ground surface.