GB2272464A - Soil strengthening - Google Patents

Abstract

A method of strengthening soil includes the steps of burying in the soil, in the vicinity of an area which is to be load bearing, one or more circular reinforcements. The reinforcements might be of ring form, channelled, or cylindrical, and might be formed, for example from used tyres.

Description

EARTH REINFORCEMENT The present invention is concerned with earth reinforcement.

A prime consideration in any construction project, whether for buildings or for transport pathways, is the load bearing properties of the foundation soil. The capacity of soil is determined by a number of factors, some of which may vary considerably as a result of uncontrollable factors such as climate. Many methods of enhancing soil strength are well established, and include, for example, piling, ground treatment by cement, chemical stabilisation, and dewatering.

There are also many methods known which use soil reinforcement techniques where various types of anchors are buried in the soil. The expense of these known methods is significant, sometimes to the extent that it is the deciding factor as to whether or not a project is viable.

There is therefore continuous research into methods for improving soil strength at acceptable cost.

According to the present invention a method of strengthening soil includes the step of burying in the soil, in the vicinity of an area which is to be load bearing, one or more circular reinforcements.

The circular reinforcements might be of ring form, having a toroidal or a channelled cross-section, or might be cylindrical, and might be formed of any suitable material such as metal, geotextiles, geogrids, or fibre- reinforced concrete. Used tyres might also be used, as may sections of pressure piping.

The circular reinforcements might be used singly, but will usually be present in number, being arranged, for example, in one or more rings, lines, combinations thereof, or even randomly.

The reinforcements might be installed by, for example, direct driving, which may be assisted by percussive action, particularly in granular soils. Alternatively the reinforcements might be rotated to produce a partial cutting, partial driving and partial displacement action. Th some cases excavation, positioning of the reinforcements and replacement of soil might be called for. It might be desirable or even necessary in some cases to compact the soil after burial of the reinforcements therein, and this might be effected by normal compaction methods such as pile-driving, which might be amplified by the use of inserts such as short rods, batons, or wedges.

The reinforcements improve the load and bearing characteristics of soil in which they are buried by constraining the lateral and shear forces induced in the soil by a vertical load. Expansion of the reinforcements in response to expansion of soil contained therein will be resisted not only by the inherent strength of the reinforcements themselves but also by the presence of soil outside the reinforcements. There is also a friction effect between the soil and surfaces of the reinforcements which resists relative vertical movement between the two and therefore increases soil strength.

It will be realised that the size of each particular reinforcement, the numbers of reinforcements used for a particular installation, and the disposition of the reinforcements will depend on the type of soil present and on the nature of the support which the soil is required to provide. Varying the various parameters to optimise any particular installation in terms of strength and of cost is the task of those skilled in this particular type of installation.

Claims (5)

1. What is claimed is: 1. A method of strengdhening soil including the step of burying in the soil, in the vicinity of an area which is to be load bearding, one or more circular reinforcements.
2. 2. A method as claimed in Claim 1 wherein there are several rinforcements.
3. 3. A method as claimed in Claim 1 or in Claim 2 wherein each reinforcement is of ring form, having a toroidal or a channelled cross-section.
4. 4. A method as claimed in Claim 1 or in Claim 2 wherein each reinforcement is of cylindrical form.
5. 5. A method of strengthening soil substantially as herein described.