Pali Radice (literal translation ‘Root Pile’ from the Italian) is a versatile foundation system using small diameter cast in situ bored piles, developed in Italy in the 1950s. It has been extensively employed as an underpinning/stabilisation system for strengthening existing foundations which are settling or are required to support increased loads.

Common uses

Underpinning to existing structures
Stabilisation of bridge structures and retaining walls
Stabilisation of listed/old structures
Stabilisation of embankments and cuttings
Upgrading of existing structural foundations
Supplementary support for upward or outward extension of existing structures
Boring through obstruction-laden ground to form new load bearing foundations and minipiled retaining walls
Strip footing underpinning
Column base underpinning for adding additional storeys to buildings

Process

The piles are formed using specialist rotary drilling rigs (so that virtually no vibration is transmitted to the structure) by boring a temporary steel casing to depth using a special cutting bit.

A drilling fluid (usually water) is circulated through the casing so that it cools the cutting bit and returns outside the casing, transporting the arisings with it to the settlement tanks. 
To enable the drilling rigs to operate in restricted headroom, short lengths of casing are coupled together during boring.

These specialist rigs are also narrow enough to fit into tight spaces and many are electric-powered, enabling them to operate safely where conditions are limited in other ways.

Advantages

The versatility of the drilling rigs enables piles to be constructed through a succession of strata or artificial obstructions in a single operation
The grout mix can penetrate into the sub-soil, thereby automatically filling any cavities and forming an intimate bond between the pile and the ground
Pali Radice can be formed at any angle, even alongside existing buildings or industrial plant
The special cutting bits enable piles to be constructed through virtually any buried obstruction
Noise levels are far less than those normally associated with other forms of piling
The process is virtually vibration-free because the piles are formed by rotary drilling
Drilling rigs can access working areas via normal doorways and piles can be installed vertically 300 mm from an existing wall measured to the centre line of the pile