Abstract: A tamper device including a shaft for driving a tamper head, and a shield. A tamper head is attached to the end of the shaft for tamping a lift of aggregate in a cavity formed in a ground surface. A shield attached to the tamper device and spaced a predetermined distance above a top surface of the tamper head, the shield having a predetermined length extending upwardly above the tamper head sufficient to prevent sidewalls of a cavity in soft soil in which the tamper device is used from failing and collapsing into the cavity. Methods of constructing aggregate columns with thicker lifts are also disclosed.

Abstract: A primary earth penetrating mandrel formed of a hollow shell steel plate octagonal in cross-section has an upper end and a blunt lower end joined by an upwardly and outwardly tapered wall. The mandrel is driven down in the earth to simultaneously form a vertical tapered cavity while compacting the sidewall of the cavity to provide structural integrity. The mandrel is then moved upwardly from the bottom of the cavity and aggregate is deposited in the bottom of the cavity then the mandrel is lowered so that its blunt lower end densifies the aggregate by vertical vibratory action and static force and repeating these until the pier top is near the surface of the earth at which time the upper aggregate portions are densified by the primary mandrel or a secondary mandrel having a substantially larger lower end surface than the lower end surface of the primary mandrel.

Abstract: A tamper device including a shaft for driving a tamper head, and a shield. A tamper head is attached to the end of the shaft for tamping a lift of aggregate in a cavity formed in a ground surface. A shield attached to the tamper device and spaced a predetermined distance above a top surface of the tamper head, the shield having a predetermined length extending upwardly above the tamper head sufficient to prevent sidewalls of a cavity in soft soil in which the tamper device is used from failing and collapsing into the cavity. Methods of constructing aggregate columns with thicker lifts are also disclosed.

Abstract: A primary earth penetrating mandrel formed of a hollow shell steel plate octagonal in cross-section has an upper end and a blunt lower end joined by an upwardly and outwardly tapered wall. The mandrel is driven down in the earth to simultaneously form a vertical tapered cavity while compacting the sidewall of the cavity to provide structural integrity. The mandrel is then moved upwardly from the bottom of the cavity and aggregate is deposited in the bottom of the cavity then the mandrel is lowered so that its blunt lower end densifies the aggregate by vertical vibratory action and static force and repeating these until the pier top is near the surface of the earth at which time the upper aggregate portions are densified by the primary mandrel or a secondary mandrel having a substantially larger lower end surface than the lower end surface of the primary mandrel.

Abstract: A slotted mandrel is used in displacement pier construction. Longitudinal slots are formed in the sides of the hollow mandrel which allow for the introduction of aggregate efficiently into the mandrel from a hopper through which the mandrel passes while being driven into the ground. Water may also be employed with the aggregate. Once in the ground the mandrel is raised to release the aggregate (and water if present) into the formed hole in lifts and a mandrel head then compacts the aggregate in the hole. This apparatus and method obviates the need for complicated and expensive hoppers that are raised with the mandrel or the use of expensive aggregate delivery systems.

Abstract: A primary earth penetrating mandrel formed of a hollow shell steel plate octagonal in cross-section has an upper end and a blunt lower end joined by an upwardly and outwardly tapered wall. The mandrel is driven downwardly in the earth to simultaneously form a vertical tapered cavity while compacting the sidewall of the cavity to provide structural integrity. The mandrel is then moved upwardly from the bottom of the cavity and aggregate is deposited in the bottom of the cavity following which the mandrel is lowered so that its blunt lower end engages the deposited aggregate and densifies the aggregate by vertical vibratory action and static force with these steps being repeated until the pier top is near the surface of the earth at which time the upper aggregate portions are densified by either the primary mandrel or a secondary mandrel having a substantially larger lower end surface than the lower end surface of the primary mandrel.

Abstract: A slotted mandrel is used in displacement pier construction. Longitudinal slots are formed in the sides of the hollow mandrel which allow for the introduction of aggregate efficiently into the mandrel from a hopper through which the mandrel passes while being driven into the ground. Water may also be employed with the aggregate. Once in the ground the mandrel is raised to release the aggregate (and water if present) into the formed hole in lifts and a mandrel head then compacts the aggregate in the hole. This apparatus and method obviates the need for complicated and expensive hoppers that are raised with the mandrel or the use of expensive aggregate delivery systems.

Abstract: A primary earth penetrating mandrel formed of a hollow shell steel plate octagonal in cross-section has an upper end and a blunt lower end joined by an upwardly and outwardly tapered wall. The mandrel is driven downwardly in the earth to simultaneously form a vertical tapered cavity while compacting the sidewall of the cavity to provide structural integrity. The mandrel is then moved upwardly from the bottom of the cavity and aggregate is deposited in the bottom of the cavity following which the mandrel is lowered so that its blunt lower end engages the deposited aggregate and densifies the aggregate by vertical vibratory action and static force with these steps being repeated until the pier top is near the surface of the earth at which time the upper aggregate portions are densified by either the primary mandrel or a secondary mandrel having a substantially larger lower end surface than the lower end surface of the primary mandrel.

Abstract: Installation of support piers for a structure comprises the steps of positioning a hollow tube in a soil matrix followed by removal of soil from the hollow core, filling the core with an aggregate, subsequent raising and lowering of the hollow tube, compacting the aggregate by means of a mechanical device affixed to the bottom of the hollow tube to and also applying lateral forces to the aggregate against the walls of the cavity formed in the soil matrix, thereby pushing a portion of the aggregate laterally into the soil matrix.

Abstract: A method and special mechanical apparatus for installation of support pier for structure comprises positioning a hollow tube apparatus in a soil matrix wherein the hollow tube apparatus has a hollow core and is susceptible to lateral and longitudinal movement, removing soil from the hollow core and then filling that core with an aggregate followed by raising and lowering of the hollow tube apparatus by means of a special bottom mechanical device in a manner which compacts the aggregate and also applies lateral forces to the aggregate against the walls of the cavity in the soil matrix, pushing a portion of the aggregate into the soil matrix.

Abstract: A method and mechanical apparatus for installation of support pier for structure comprises positioning a hollow tube apparatus in a soil matrix wherein the hollow tube apparatus has a hollow core and is susceptible to lateral and longitudinal movement, removing soil from the hollow core and then filling that core with an aggregate followed by raising and lowering of the hollow tube apparatus by way of a bottom mechanical device in a manner which compacts the aggregate and also applies lateral forces to the aggregate against the walls of the cavity in the soil matrix, pushing a portion of the aggregate into the soil matrix.

Abstract: A method and special mechanical apparatus for installation of support pier for structure comprises positioning a hollow tube apparatus in a soil matrix wherein the hollow tube apparatus has a hollow core and is susceptible to lateral and longitudinal movement, removing soil from the hollow core and then filling that core with an aggregate followed by raising and lowering of the hollow tube apparatus by means of a special bottom mechanical device in a manner which compacts the aggregate and also applies lateral forces to the aggregate against the walls of the cavity in the soil matrix, pushing a portion of the aggregate into the soil matrix.

Abstract: A method and apparatus for installation of a support pier for a structure comprises positioning a hollow tube apparatus in a soil matrix wherein the hollow tube apparatus has a hollow core and is susceptible to lateral and longitudinal movement, removing soil from the hollow core and then filling that core with an aggregate followed by raising and lowering of the hollow tube apparatus by a bottom mechanical device in a manner which compacts the aggregate and also applies lateral forces to the aggregate against the walls of the cavity in the soil matrix, pushing a portion of the aggregate into the soil matrix.

Abstract: A method and special mechanical apparatus for installation of support pier for structure comprises positioning a hollow tube apparatus in a soil matrix wherein the hollow tube apparatus has a hollow core and is susceptible to lateral and longitudinal movement, removing soil from the hollow core and then filling that core with an aggregate followed by raising and lowering of the hollow tube apparatus by means of a special bottom mechanical device in a manner which compacts the aggregate and also applies lateral forces to the aggregate against the walls of the cavity in the soil matrix, pushing a portion of the aggregate into the soil matrix.