The invention relates to a foundation engineering method and a construction apparatus for producing a columnar structure in the ground, in which a foundation engineering tool is driven in a rotating manner about an axis of rotation and introduced with a feeding motion into a ground, wherein the columnar structure is produced in the ground. According to the invention it is provided that during the production of the columnar structure a rotating motion and a feeding motion of the foundation engineering tool are recorded over time and forwarded to an evaluation unit, in that by means of a sensor means at least one further processing parameter is recorded over time during the production of the columnar structure in the ground and is forwarded to the evaluation unit and in that by the evaluation unit a three-dimensional model of the columnar structure is produced and displayed.

A concrete inside interface processing structure for secant pile construction, including secant concrete pile, formed plain concrete pile, rotary jet grouting piles, steel mesh sheet, ribbed steel bar, Y-shaped connecting piece, reinforced concrete pile, and U-shaped connecting piece; drilled holes are arranged at intervals along axis of the formed plain concrete pile; the ribbed steel bar is anchored in each drilled hole; the steel mesh sheet is formed by connecting longitudinal bars and transverse bars, and driven into a soil body between the formed plain concrete piles; the concrete layer is formed by spraying concrete on the steel mesh sheet; the reinforced concrete pile is cast at outside of the formed plain concrete pile, and tangent to the formed plain concrete pile, and interlocked with the rotary jet grouting piles; the rotary jet grouting piles are tangent to the formed plain concrete pile or secant concrete pile.

A concrete inside interface processing structure for secant pile construction, including secant concrete pile, formed plain concrete pile, rotary jet grouting piles, steel mesh sheet, ribbed steel bar, Y-shaped connecting piece, reinforced concrete pile, and U-shaped connecting piece; drilled holes are arranged at intervals along axis of the formed plain concrete pile; the ribbed steel bar is anchored in each drilled hole; the steel mesh sheet is formed by connecting longitudinal bars and transverse bars, and driven into a soil body between the formed plain concrete piles; the concrete layer is formed by spraying concrete on the steel mesh sheet; the reinforced concrete pile is cast at outside of the formed plain concrete pile, and tangent to the formed plain concrete pile, and interlocked with the rotary jet grouting piles; the rotary jet grouting piles are tangent to the formed plain concrete pile or secant concrete pile.

A ground improvement apparatus includes: an irrotational sun gear fixed to an irrotational inner pipe inside a rotatable outer pipe; a planetary gear rotatably supported on a rotatable agitation shaft and configured to rotate while meshing with the sun gear; and an inverse rotation mechanism meshing with the planetary gear and rotating the agitation shaft in an opposite direction of the planetary gear. The agitation shaft is suspended on a connection member attached to the outer pipe so as to rotate in synchronization with a rotation center of the inverse rotation mechanism. A ground where the outer pipe is penetrated and a solidifying material discharged from the agitation shaft are agitated and mixed with each other by agitation blades radially attached to the agitation shaft with a trajectory of distal ends of the agitation blades drawing a substantially polygonal shape by rotation of the agitation shaft.

A ground improvement apparatus includes: an irrotational sun gear fixed to an irrotational inner pipe inside a rotatable outer pipe; a planetary gear rotatably supported on a rotatable agitation shaft and configured to rotate while meshing with the sun gear; and an inverse rotation mechanism meshing with the planetary gear and rotating the agitation shaft in an opposite direction of the planetary gear. The agitation shaft is suspended on a connection member attached to the outer pipe so as to rotate in synchronization with a rotation center of the inverse rotation mechanism. A ground where the outer pipe is penetrated and a solidifying material discharged from the agitation shaft are agitated and mixed with each other by agitation blades radially attached to the agitation shaft with a trajectory of distal ends of the agitation blades drawing a substantially polygonal shape by rotation of the agitation shaft.

A grouting and pile forming device includes a compartment box and a double-spiral-tube structure. The double-spiral-tube structure includes an outer spiral tube and an inner spiral tube, which are nested and fixed together. A top part of the outer spiral tube and a top part of the inner spiral tube are hermetically connected. An inner space of the inner spiral tube forms a grouting cavity. A space between the outer spiral tube and the inner spiral tube forms a drainage and delivery cavity. A plurality of drainage and delivery holes are provided in a tube body of the outer spiral tube. A construction method for strengthening soft soil through the grouting and pile forming device includes the following steps: 1) operation preparation; 2) downward spiral penetration; 3) drainage consolidation; 4) chemical consolidation; 5) upward spiral lifting; and 6) repeated operation until all soil to be strengthened is treated.

A grouting and pile forming device includes a compartment box and a double-spiral-tube structure. The double-spiral-tube structure includes an outer spiral tube and an inner spiral tube, which are nested and fixed together. A top part of the outer spiral tube and a top part of the inner spiral tube are hermetically connected. An inner space of the inner spiral tube forms a grouting cavity. A space between the outer spiral tube and the inner spiral tube forms a drainage and delivery cavity. A plurality of drainage and delivery holes are provided in a tube body of the outer spiral tube. A construction method for strengthening soft soil through the grouting and pile forming device includes the following steps: 1) operation preparation; 2) downward spiral penetration; 3) drainage consolidation; 4) chemical consolidation; 5) upward spiral lifting; and 6) repeated operation until all soil to be strengthened is treated.

Provided is a novel drilling apparatus for drilling into prepared ground surfaces and natural ground conditions. The apparatus includes a mast assembly, a support structure assembly flexibly coupled with the mast assembly, a plurality of drill assemblies affixed to the support structure assembly, and a frame. Also provided is a method of drilling into a ground surface, by providing a drilling apparatus having a mast assembly, a support structure assembly flexibly coupled with the mast assembly, a plurality of drill assemblies affixed to the support structure assembly, and a frame. Each of the drill assemblies include a hollow drill rod with a drill bit at one end, the bit having exterior cutting elements and interior fluid diverters. Pressurized fluid and torque is supplied to the drill rods, and by means of the mast assembly and support structure assembly the drill rods are moved downward so that using the downward and rotational force, and the pressurized fluid, the drill bits drill into the ground surface.

Methods of preparing cast-in-place geopolymer piles using electrical heating wire (130) to provide heat to cure the piles are described. The heating wire (130) can be associated with a reinforcement cage (120) inserted in the pile shaft. Rod-shaped heating units comprising electrical heating wire (130) can be inserted into a pile shaft and can be reusable. Geopolymer piles with high compressive strength can be prepared from mixtures of class F fly ash and aqueous sodium hydroxide by heating the piles with the heating wire to a stable curing temperature for at least about 24 hours.

The invention relates to a foundation engineering method and a construction apparatus for producing a columnar structure in the ground, in which a foundation engineering tool is driven in a rotating manner about an axis of rotation and introduced with a feeding motion into a ground, wherein the columnar structure is produced in the ground. According to the invention it is provided that during the production of the columnar structure a rotating motion and a feeding motion of the foundation engineering tool are recorded over time and forwarded to an evaluation unit, in that by means of a sensor means at least one further processing parameter is recorded over time during the production of the columnar structure in the ground and is forwarded to the evaluation unit and in that by the evaluation unit a three-dimensional model of the columnar structure is produced and displayed.