System for installing material in the ground

Procedure for inserting a wall of material into the ground, including the steps:

• of providing a caisson P, wherein:
• the caisson P is a structure having a generally tubular wall, the wall being in two separably engageable sectors, PA and PB, which are such, when enagaged, as to form a complete encirclement around a hollow interior;
• the caisson is so formed as to be capable, when the two separable sectors are engaged, of being pile-driven into the ground as an integral whole tubular unit;
• of pile-driving the caisson P, with the two sectors PA and PB engaged, down into the ground;
• with the caisson P in place in the ground, of extracting the native soil from the hollow interior of the caisson P;
• with the caisson P still in place in the ground, of introducing a body of material into the hollow interior of the caisson P;
• of extracting sector PB from caisson P, and removing sector PB from the ground, sector PA remaining in the ground;
• of providing a second caisson Q, corresponding to caisson P, caisson Q having corresponding separable sectors QA and QB;
• wherein the structure of the sectors is such that sector QA is separably engageable with sector PA when sector PB is separated from sector PA, and sector PA is separably engageable with sector QA when sector QB is separated from sector QA;
• after extracting sector PB, of engaging sector QA with sector PA;
• of pile-driving the caisson Q, the caisson Q having the two sectors QA and QB engaged, down into the ground;
• with the caisson Q in place in the ground, of extracting the native soil from the hollow interior of the caisson Q;
• with the caisson Q still in place in the ground, of introducing a body of material into the hollow interior of the caisson Q;
• of extracting sector QB from caisson Q, and removing sector QB from the ground, sector QA remaining in the ground;
• after extracting sector QB, of engaging sector PA with sector QA;
• of enagaging sector PB once more with sector PA, thereby re-forming caisson P;
• of pile-driving the caisson P, the caisson P having the two sectors PA and PB engaged, down into the ground;
• of inserting and removing the caissons P and Q into the ground progressively, sector by sector, in overlapping configuration, thereby progressively forming in the ground a continuous wall of the introduced material.

Procedure for sealing the joints, and the bottom, of an anti-leakage in-ground barrier composed of sheet metal elements pile-driven into the ground, wherein:

• the elements are formed with mechanically-interlocking edge-forms at the joints between the elements, which, when interlocked, and when the elements have been driven into the ground, define and form the walls of a cavity at the joint extending from the surface to the bottom of the barrier, the cavity being, in plan view, in series with any leak-path present in the interlocked edge-forms;
• at or adjacent to the bottom of the cavity, the wall of the cavity is provided with a through-hole;
• a sealant injection tube is provided, which is so adapted that the tube can be sealably connected inside the cavity to the through-hole, being sealed to the extent that sealant injected into the tube passes out through the through-hole, and does not enter the cavity;
• the tube is connectable to the through-hole, inside the cavity, in such a manner than the tube can be disconnected therefrom;
• the through-hole is formed with a plug-seat;
• a self-sealing plug is provided, which, when urged into contact with the plug-seat, seals itself thereto, and closes off the through-hole;
• the procedure includes the steps:
• of placing the sealant injection tube inside the cavity, with an upper end of the tube accessible at the surface, and which extends down the cavity to, or adjacent to, the bottom thereof;
• of connecting the tube to the through-hole;
• of injecting sealant through the tube and through the through-hole, into the ground outside the cavity at, or adjacent to, the bottom of the cavity;
• after having injected the sealant through the through-hole, of placing the plug in the tube, whereby the plug passes down the tube along with the sealant when the sealant is injected through the tube, and whereby the plug seals itself into the plug-seat;
• after the plug is sealed into the plug-seat, of disconnecting the tube from the through-hole;
• of passing a flush-pipe down into the cavity, from the surface, and flushing out the cavity until the cavity is clean and clear;
• of passing a sealant injection tube down into the cavity, from the surface, and of injecting sealant into the cavity, from top to bottom, thereby sealing off the said leak-path at the joint.

Procedure for installing in the ground a prism of a treatment material and a watertight barrier comprising elements of the type that are suitable to be pile-driven into the ground, including the steps:

• of providing a caisson, wherein:
• the caisson has a generally tubular wall, which is such as to form a complete encirclement around a hollow interior;
• the wall of the caisson is so formed as to be capable of being pile-driven into the ground as an integral whole tubular unit;
• of pile-driving the caisson down into the ground;
• with the caisson in place in the ground, of introducing a body of the treatment material into the hollow interior of the caisson;
• of withdrawing the caisson up out of the ground, whereby a prism of the treatment material is left in the ground;
• of inserting the waterproof barrier down into the ground, and of so positioning adjacent elements of the barrier that respective edges of the adjacent elements are spaced apart in such a manner as to define a physical gap or gate in the barrier, between the edges of the adjacent elements of the barrier, through which groundwater may flow;
• wherein, in respect of both the said adjacent elements of the barrier:
• the location of the edge of the element of the barrier during and after insertion is such that a first portion of the barrier lies outside the prism of the treatment material, and a second portion of the barrier, being a portion which includes the said edge of the element of the barrier, extends into, and lies within, the said prism of the material:
• in a cross sectional plan view of the prism and the barrier after insertion of the barrier, a substantial length of the periphery of the barrier lies in contact with the said treatment material;
• and the position of the barrier relative to the prism is such that groundwater may flow around the barrier and through the prism of material.