Strengthening cohesive soils

Claim 2

Apparatus for stabilizing cohesive soil to substantial depths which involves driving down into the earth an implement designed as an injector for a binder and having binder outlet apertures formed adjacent its lower end, which appartus comprises a rotarytype earth drill having a drill head mounted on the end of a drill rod and provided with one or more helices and with a number of outlet apertures communicating with pressurized-binder supply conduit extending downwardly through the drill rod, said outlet apertures being located in a lower cutting face of a helix and distributed radially over these faces, means for rotating the drill in a desired direction of rotation, means effective upon screwing the earth drill upwardly to forcibly impart thereto an upwardly directed feed movement which during each revolution of the drill is considerably smaller than the pitch of the helix or helices, the drill head being adapted to positively distribute the binder over the entire cross section of the drill head.

Claim 3

Apparatus as claimed in claim 1, characterized in that below the helix or helices provided with outlet apertures for the binder there is provided one or more further helices which have the function to mix the deposited binder with the soil and to effect a packing action on the underlying column of soil admixed with the binder.

Claim 4

Apparatus as claimed in claim 1, characterized in that the helices are straightly cut off at a lower edge provided with outlet apertures, and in that each helix carries at the said lower edge a foldable cutter which is adapted during screwing down the earth drill into the ground to occupy a position to close off the binder fluid outlet apertures but upon rotating the drill in the opposite sense to pivot into a position to open the apertures.

Claim 5

Apparatus according to claim 1, characterized in that the drill rod is guided by a guide column, the upper end of the rod being rotatably but axially non-displaceably mounted in a slide slidable along said guide column and having the vertical feed movement transmitted thereto by means of an endless chain extending about sprockets journalled on the guide column.

Claim 6

Apparatus according to claim 1, characterized in that the rotational movement of the drill and its vertical feed movement are derived from a common power source so that the feed movement is proportional to the rotational movement.

Claim 7

Apparatus according to claim 5, characterized in that the vertical feed movement is transmitted from a drive shaft for the drill through a change-speed gearing.

Claim 8

Apparatus according to claim 5, characterized in that the earth drill is adapted to receive air-borne binder powder.

Claim 9

Apparatus according to claim 1, characterized in that there is provided for supplying binder fluid to the outlet apertures of the drill crown a pump of a conventional type adapted to deliver a predetermined fluid volume per revolution.

Claim 10

Apparatus according to claim 8, characterized in that the pump is connected to the same source of power as the earth drill through an overrunning clutch in such a way as to be inoperative during screwing down the drill into the earth, but to deliver during the screwing withdrawal of the drill an amount of binder fluid proportional to the feed movement of the drill.

Claim 11

Apparatus for stabilizing cohesive soil to substantial depths which involves driving down into the earth an implement designed as an injector for a binder and having binder outlet apertures formed adjacent its lower end, which apparatus comprises a rotary-type earth drill having a drill head mounted on the end of a drill rod and provided with one or more helices and with a number of outlet apertures communicating with pressurized-binder supply conduit extending downward through the drill rod, means for rotating the drill in a desired direction of rotation, means effective upon screwing the earth drill upwardly to forcibly impart thereto an upwardly directed feed movement which during each revolution of the drill is considerably smaller than the pitch of the helix or helices, the drill head being adapted to positively distribute the binder over the entire cross section of the drill head, a lost-motion clutch being mounted in the drill rod and adapted, through the intermediary of a movement transmitting system, upon relative movement between the clutch members, to actuate a valve mounted in the binder fluid supply conduit so as to cause the valve to be closed during screwing down the drill into the earth but to be opened when, during its withdrawal from the earth, the drill is rotated in the opposite sense.

Claim 12

Apparatus for stabilizing cohesive soil to substantial depths which involves driving down into the earth an implement designed as an injector for a binder and having binder outlet apertures formed adjacent its lower end, which apparatus comprises a rotary-type earth drill having a drill head mounted on the end of a drill rod and provided with one or more helices and with a number of outlet apertures communicating with pressurized-binder supply conduit extending downward through the drill rod, means for rotating the drill in a desired direction of rotation, means effective upon screwing the earth drill upwardly to forcibly impart thereto an upwardly directed feed movement which during each revolution of the drill is considerably smaller than the pitch of the helix or helices, the drill head being adapted to positively distribute the binder over the entire cross section of the drill head, a lost-motion clutch being mounted in the drill rod and adapted, through the intermediary of a movement transmitting system, upon relative movement between the clutch members, to actuate a valve mounted in the binder fluid supply conduit so as to cause the valve to be closed during screwing down the drill into the earth but to be opened when, during its withdrawal from the earth, the drill is rotated in the opposite sense.

Claim 13

Apparatus according to claim 10, characterized in that the earth drill, working as an injection nozzle, is adapted to supply binder in the form of a dry powder.

Claim 14

Apparatus according to claim 11, characterized in that the earth drill is adapted to receive easily breakable capsules, fed by means of pressure air and containing powdered binder.

Claim 15

Apparatus according to claim 11, characterized in that a gas tight supply tube for the air-borne binder is positioned above the hollow drill bar, the lower end of said supply tube freely emerging in a chamber in the drill head that communicates with outlet channels for the binder, and has a cross-sectional dimension such that between the tube and the surrounding drill bar wall an air flow channel is formed which has a ring-shaped cross-section, the area of which is substantially greater than the inner cross-section area of the tube, and which at the top communicates with the free air through preferably adjustable throttle apertures.

Claim 16

Apparatus according to claim 13 having an adjustable throttle valve for the discharging of air, characterized in that the adjustment of the throttle valve is controlled from the driving mechanism of the earth drill so that the pressure of the gas flowing through the chamber always is greater than the pressure from the earth mass or the ground water around the drill head.

Claim 17

Apparatus for stabilizing cohesive soil to substantial depths which involves moving down into the earth an implement designed as an injector for a binder and having binder outlet apertures formed adjacent its lower end, which apparatus comprises a rotary-type earth drill having a drill head mounted on the end of a drill rod and provided with one or more helices and with a number of outlet apertures communicating with pressurized-binder supply conduit extending downward through the drill rod, means for rotating the drill in a desired direction of rotation, means effective upon screwing the earth drill upwardly to forcibly impart thereto an upwardly directed feed movement which, during each revolution of the drill, is considerably smaller than the pitch of the helic or helices, said outlet apertures being positioned close to the drill head spindle below the upper end of a helix or helices, and that below the binder discharge aperture or apertures there are provided one or more further helices which have a breadth successively increasing from the drill spindle and have the function to move by their outer edges, in a radial direction, the binder material deposited in the earth mass over the cross section of the drill hole and to mix the binder with the adjacent portions of the soil filling the drill hole.

Claim 18

Apparatus for stabilizing cohesive soil to substantial depths which involves moving down into the earth an implement designed as an injector for a binder and having binder outlet apertures formed adjacent its lower end, which apparatus comprises a rotary-type earth drill having a drill head mounted on the end of a drill rod and provided with one or more helices and with a number of outlet apertures communicating with pressurized-binder supply conduit extending downward through the drill rod, means for rotating the drill in a desired direction of rotation, means effective upon screwing the earth drill upwardly to forcibly impart thereto an upwardly directed feed movement which, during each revolution of the drill, is considerably smaller than the pitch of the helic or helices, said outlet apertures being positioned close to the drill head spindle below the upper end of a helix or helices, and that below the binder discharge aperture or apertures there are provided one or more further helices which have a breadth successively increasing from the drill spindle and have the function to move by their outer edges, in a radial direction, the binder material deposited in the earth mass over the cross section of the drill hole and to mix the binder with the adjacent portions of the soil filling the drill hole.

Claim 19

Apparatus for stabilizing cohesive soil to substantial depths which involves moving down into the earth an implement designed as an injector for a binder and having binder outlet apertures formed adjacent its lower end, which apparatus comprises a rotary-type earth drill having a drill head mounted on the end of a drill rod and provided with one or more helices, a capsule feeding tube being provided for the feeding of easily breakable capsules containing powdered binder to outlet apertures for the binder, provided in the drill head, said tube being gas-tight inserted in the hollow drill bar and at the lower end on its inner side provided with capsule breaking cutters, and above these cutters provided with air discharge apertures in the tube wall, and that the ring-shaped air flow channel between the tube and surrounding drill bar wall communicates with the outer air through preferably adjustable throttle apertures.

Claim 20

Apparatus for stabilizing cohesive soil to substantial depths which involves moving down into the earth an implement designed as an injector for a binder and having binder outlet apertures formed adjacent its lower end, which apparatus comprises a rotary-type earth drill having a drill head mounted on the end of a drill rod and provided with one or more helices, a capsule feeding tube being provided for the feeding of easily breakable capsules containing powdered binder to outlet apertures for the binder, provided in the drill head, said tube being gas-tight inserted in the hollow drill bar and at the lower end on its inner side provided with capsule breaking cutters, and above these cutters provided with air discharge apertures in the tube wall, and that the ring-shaped air flow channel between the tube and surrounding drill bar wall communicates with the outer air through preferably adjustable throttle apertures.