Abstract: A stop-end pipe is used for formation of joining surfaces between adjacent wall elements made from a concrete casting, of the type consisting of a substantially trapezium-shaped profiled section divided up into at least two wings these wings are resiliently approachable to one another and also have a double internal reinforcing partition able to prevent collapsing as a result of compression. Preferably, the double partition is partially widened out so as to form a guide channel in which a guiding pawl for a working tool is able to slide.

Abstract: According to the present invention, tunnels, particularly shallow tunnels, are constructed by excavating slurry filled cross-trenches in a direction transverse to the axis of the tunnel and at regular intervals along the line or axis of the tunnel. Prefabricated frame elements are inserted into the cross-trenches to, in essence, create the tunnel wall lateral support structure before the tunnel walls are installed. Then the tunnel sidewalls are excavated under bentonite clay or mud slurry to form cross-slots between the previously installed support frames. Precast concrete sidewalls or panels are inserted between the support frames. The frames and sidewalls have interlocking tongue and groove or keyway structures so as to interfit and lock same into position.

Abstract: High density polyethylene sheets are sealed at their lateral edges to form a sheath or envelope for sandwiching a drain mesh. A plurality of spaced apart bore holes is formed along the line of the cut-off and drain barrier and a coupling member is positioned, one in each bore hole, respectively, each coupling member having at least one locking keyway slot formed in a side thereof. These coupling members have stainless steel keyway protectors or cement stops so that cementious material cast in the bore holes so as to stabilize the coupling members do not fill the keyways. After the cementious material has set, the space between bore holes up to the keyway slots is excavated including the cementious material between the facing edges of the keyway material. Then the drain barrier with rigidifying perforated pipes secured in the ends thereof is inserted into the excavated slot with the perforated pipes being telescopically received in and retained by the keyway slots.

Abstract: A method of measuring the deviation of the run of the actual vertical center axis of fluid filled bore holes and trenches relative to the direction of the design center axis thereof which bore holes and trenches are excavated under bentonite slurry comprises inserting into said bore holes and trenches a gauge means suspended from a cable means, whereby said gauge means is arrested inside said bore hole at any desired level, and thereafter a measuring cable means is connected to said gauge means and substantially tensioned and brought to run in an exact vertical direction whereupon above ground level the horizontal deviation of said cable means from the design center line of said bore hole or said trench is measured.