A method of forming a foundation in the ground, comprising the steps of—forming a foot (11) in the ground (100); —forming a column (12) made from a load bearing material in the ground (100) on top of the foot (11); and —forming a pile (13) in the material column (12) such that the pile (13) extends down to the material foot (11) or into the material foot (11).

A method of forming a foundation in the ground, comprising the steps of—forming a foot (11) in the ground (100); —forming a column (12) made from a load bearing material in the ground (100) on top of the foot (11); and —forming a pile (13) in the material column (12) such that the pile (13) extends down to the material foot (11) or into the material foot (11).

The present invention discloses a jetting, expansion and extrusion combined pile, a construction method thereof and a spiral jetting, expansion and extrusion drilling rig used in the method. A pile of the combined pile comprises a pile body (101), an expanded body (103) and a pile end (106). At least one double-frustum-shaped expanded body (103), which is integrally formed with the pile body (101), is arranged on the pile body (101). The expanded body (103) is located in a vertical soil layer position, which has higher deformation modulus and shear strength, of the pile body (101), and at least two wing plates (102) which are uniformly distributed in the circumference direction and basically perpendicular to the axis of the pile are arranged on the pile body (101). The diameter of the pile above the expanded body (103) is larger than or equal to that of the pile below the expanded body (103). The drilling rig in the present invention comprises an upper section and a lower section, the diameter of the upper section is larger than that of the lower section, and the expanded body can be produced in any required position conveniently. When the expanded body (103) is located at the upper part or in the middle of the combined pile, if the diameter of the pile above the expanded body (103) is larger than that of the pile below the expanded body (103), the consumption of concrete can be greatly reduced.

The present invention discloses a jetting, expansion and extrusion combined pile, a construction method thereof and a spiral jetting, expansion and extrusion drilling rig used in the method. A pile of the combined pile comprises a pile body (101), an expanded body (103) and a pile end (106). At least one double-frustum-shaped expanded body (103), which is integrally formed with the pile body (101), is arranged on the pile body (101). The expanded body (103) is located in a vertical soil layer position, which has higher deformation modulus and shear strength, of the pile body (101), and at least two wing plates (102) which are uniformly distributed in the circumference direction and basically perpendicular to the axis of the pile are arranged on the pile body (101). The diameter of the pile above the expanded body (103) is larger than or equal to that of the pile below the expanded body (103). The drilling rig in the present invention comprises an upper section and a lower section, the diameter of the upper section is larger than that of the lower section, and the expanded body can be produced in any required position conveniently. When the expanded body (103) is located at the upper part or in the middle of the combined pile, if the diameter of the pile above the expanded body (103) is larger than that of the pile below the expanded body (103), the consumption of concrete can be greatly reduced.

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.

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 present application discloses a construction method for pouring concrete in a karst cave. Concrete streaming is pumped into a hollow passage of a drill stem, then opens the one-way openable sealing cover with a pre-tensioned spring on a reaming drill bit and enters the karst cave to complete pouring of the concrete. When the karst cave is relatively low, low-slump plain concrete mixed with quick-setting agents is injected through a drilling rig and the hollow drill stem to form a concrete pier; when the karst cave is relatively high, the hollow drill stem is sleeved into a thin-walled steel shell, and the thin-walled steel shell is synchronously sunk into the drilled hole while drilling, enters the karst cave and is socketed into a stable rock stratum, then concrete is pumped into the thin-walled steel shell from the bottom of the pile, and finally, a reinforcement cage is inserted to form a cast-in-place pile. Compared with the existing karst cave treatment methods, the construction method according to the present application can greatly reduce the consumption of materials, improve the mechanization of construction, simplify the construction process, shorten the construction period and reduce the engineering cost, and the cast-in-place pile with thin-walled steel shell, formed when the karst cave is relatively high, can further improve the bearing capacity of the foundation.

The present application discloses a construction method for pouring concrete in a karst cave. Concrete streaming is pumped into a hollow passage of a drill stem, then opens the one-way openable sealing cover with a pre-tensioned spring on a reaming drill bit and enters the karst cave to complete pouring of the concrete. When the karst cave is relatively low, low-slump plain concrete mixed with quick-setting agents is injected through a drilling rig and the hollow drill stem to form a concrete pier; when the karst cave is relatively high, the hollow drill stem is sleeved into a thin-walled steel shell, and the thin-walled steel shell is synchronously sunk into the drilled hole while drilling, enters the karst cave and is socketed into a stable rock stratum, then concrete is pumped into the thin-walled steel shell from the bottom of the pile, and finally, a reinforcement cage is inserted to form a cast-in-place pile. Compared with the existing karst cave treatment methods, the construction method according to the present application can greatly reduce the consumption of materials, improve the mechanization of construction, simplify the construction process, shorten the construction period and reduce the engineering cost, and the cast-in-place pile with thin-walled steel shell, formed when the karst cave is relatively high, can further improve the bearing capacity of the foundation.

Provided are a concrete foundation structure capable of firmly fixing a precast concrete foundation to a ground, and a method for constructing the concrete foundation structure. A concrete foundation structure 10 includes a precast concrete foundation 16 having a projecting portion 30 embedded in a ground G. An anchor plate 20 is placed inside an excavation hole 18 formed in the ground G, and the precast concrete foundation 16 and the anchor plate 20 are connected by a connecting member 22. In the excavation hole 18, a backfill portion 24 is formed of a backfill material 94 including a solidifying material and soil. A filler layer 26 is formed of a filler 96 containing a solidifying material between the precast concrete foundation 16 and the backfill portion 24. The precast concrete foundation 16 has a through-hole 42 through which the connecting member 22 is inserted, and the filler 96 forming the filler layer 26 is filled through the through-hole 42.

Provided are a concrete foundation structure capable of firmly fixing a precast concrete foundation to a ground, and a method for constructing the concrete foundation structure. A concrete foundation structure 10 includes a precast concrete foundation 16 having a projecting portion 30 embedded in a ground G. An anchor plate 20 is placed inside an excavation hole 18 formed in the ground G, and the precast concrete foundation 16 and the anchor plate 20 are connected by a connecting member 22. In the excavation hole 18, a backfill portion 24 is formed of a backfill material 94 including a solidifying material and soil. A filler layer 26 is formed of a filler 96 containing a solidifying material between the precast concrete foundation 16 and the backfill portion 24. The precast concrete foundation 16 has a through-hole 42 through which the connecting member 22 is inserted, and the filler 96 forming the filler layer 26 is filled through the through-hole 42.