CN113529739A

CN113529739A - Coaxial expansion body assembly type support shaftless rotary sprayer and corresponding construction method

Info

Publication number: CN113529739A
Application number: CN202110860489.XA
Authority: CN
Inventors: 王立明; 王冰璇
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-07-28
Filing date: 2021-07-28
Publication date: 2021-10-22
Anticipated expiration: 2041-07-28
Also published as: CN113529739B

Abstract

The coaxial expansion body assembly type support adopts the assembly type suspension section and the coaxial expansion body technology, increases the bearing capacity, reuses materials, reduces the cost, has controllable quality, and brings remarkable optimization and upgrading and updating to the upright column and the inclined support of the traditional foundation pit enclosure; the shaftless rotary sprayer comprises a stator flow conveyer and a rotor sprayer, has no vehicle body and no drill rod, has an automatic forward function, is used for hole leading and rotary spraying expansion construction, can also be used for construction of anchor rods, equal-thickness cement soil walls and related building envelopes, and can finish rotary spraying construction under complex conditions. The assembled support and shaftless rotary sprayer is environment-friendly, shortens construction period, facilitates construction, reduces cost, improves construction quality, has remarkable and unexpected improvements in the aspects of economy, convenience, social beneficial performance and the like compared with the prior art, has more remarkable and outstanding social and economic benefits, and further promotes the industrial upgrading of foundation pit engineering.

Description

Coaxial expansion body assembly type support shaftless rotary sprayer and corresponding construction method

Technical Field

The invention relates to the technical field of foundation pit engineering, in particular to an assembled support, and specifically relates to a coaxial expansion assembled support, a shaftless rotary sprayer and a corresponding construction method thereof.

Background

The foundation pit support (or called foundation pit enclosure) in the foundation pit engineering occupies an important part in the construction cost, and when the foundation pit enclosure pile wall adopts a fulcrum-free enclosure type and cannot meet the requirements of safety and environmental protection, a method of increasing the fulcrum is often adopted to reduce the bending moment and the shearing force of the enclosure pile wall and provide the anti-overturning capability of a support structure. The inner support is a main form of a fulcrum and comprises a flat support (horizontal support) and an inclined support (an included angle is formed between the axis of the inclined support and the horizontal plane), and the flat support generally needs to support an upright post of the flat support vertically.

At present, the upright post in the prior art is generally disposable and can not be reused. The inclined strut in the industry is divided into a traditional inclined cast strut and a front inclined strut, the inclined cast strut can be repeatedly used, but the limit of the inclined cast strut on foundation pit excavation exists, and the front inclined strut (the inclined cast strut is arranged before the earth excavation) is used for integrally arranging a component (a pile body or a pipe body) into a pit bottom soil body, so that the condition of repeated use is rarely achieved at present. In addition, the inclined pile body or the inclined strut body with the same diameter is often surplus in the bearing capacity of the member and insufficient in the bearing capacity provided by the soil body, the expansion of the member in the soil body is carried out by adopting a cement stirring or rotary spraying process which is arranged in the front (which means construction before the member is placed), the requirement that the concentricity or the coaxiality of the cement soil body and the member is difficult to ensure also exists, and the member arranged in the rear (which means construction after the cement soil is placed) can lead to the non-uniform random mixing of the original soil and the cement slurry, thereby leading to the increase of the discreteness of the supporting safety degree and the reduction of the reliability. The technology of synchronous axial grouting jacking outside the component is adopted, but the uniform and effective body expanding effect cannot be obtained.

The conventional rotary spraying process for high-pressure spraying of cement soil leads to the complexity and low efficiency of the process due to frequent disassembly of a drill rod of a pile machine, and even though a high-pressure rotary spraying device with a long drill rod is adopted, the implementation is limited by the limitation of sites and spaces, and the higher requirements of curve-shaped rotary spraying, the placement of an auxiliary supporting structure into a soil body and the like are difficult to complete.

In view of the above problems, there is a need for new and innovative ideas to bring technical progress, and the present invention will provide new and innovative technologies to improve the defects and shortcomings of the prior art.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide an assembly type support which is more cost-saving, green, environment-friendly, efficient and energy-saving, namely a coaxial expansion assembly type support which can be used as an inclined support or a vertical column of a horizontal support outside a foundation pit support; and simultaneously provides a shaftless rotary sprayer for the construction of coaxial expansion assembled supports, the construction of underground water horizontal rotary spraying bodies, the construction of anchor rods of foundation pit engineering, the pore-forming and grooving of enclosure pile walls, the formation of cement-soil walls and other processes.

In order to achieve the purpose, the coaxial expansion body assembly type support adopts the following technical scheme:

the coaxial extension body assembled support comprises a suspension section and a coaxial extension body section, wherein the suspension section is arranged between a pit bottom soil body and an enclosure structure, the coaxial extension body section is arranged below the pit bottom soil body, the coaxial extension body section comprises a lattice bearing frame and coaxial slurry, the lattice bearing frame is coincided with a longitudinal axis of the coaxial slurry, and the coaxial extension body assembled support is an inclined support for supporting a foundation pit or a stand column for supporting a foundation pit and supporting a flat support.

The longitudinal axis is an axis along the length direction of the coaxial expansion body assembled support, and the coaxial longitudinal axes are coincident.

The suspended section is arranged in an assembled mode and comprises an assembled prefabricated standard section capable of being repeatedly used, the prefabricated standard section is arranged in a hollow pipe body and made of steel, concrete or steel concrete composite materials, and the pipe wall of the pipe body is arranged in a solid mode or a lattice mode. The hollow pipe body is internally provided with a pore canal along the extension line direction of the longitudinal axis of the pipe body, and the pore canal penetrates through the longitudinal axis of the coaxial expansion body assembly type support and is directly communicated with the tail end of the lattice type bearing frame.

Optionally, the suspension section and the coaxial extension section are provided as a continuous integral member, and are placed in a soil body after being connected in sections.

Optionally, the prefabricated standard section is set as a solid (non-hollow inside) cylinder and made of steel, concrete or a steel concrete composite material.

Prefabricated standard section adopt assembled connected mode, assembled connected mode based on spacing outer barrel bolt or spacing interior barrel bolt:

the limiting outer barrel bolt is arranged as a barrel, the joint position of the prefabricated standard section is characterized in that the prefabricated standard section is wrapped outside, the inner wall of the prefabricated standard section is matched with the outer wall of the prefabricated standard section and is partially overlapped with two adjacent prefabricated standard sections respectively, the limiting outer barrel bolt is coaxial with the prefabricated standard section and is connected through a steel bolt arranged in the direction perpendicular to the longitudinal axis, the steel bolt penetrates through the prefabricated standard section and the limiting outer barrel bolt or the steel bolt does not penetrate through (is called as a bolt) the prefabricated standard section and the limiting outer barrel bolt, the limiting outer barrel bolt is arranged to limit dislocation or bending of the adjacent prefabricated standard section in the direction perpendicular to the longitudinal axis of the prefabricated standard section, the adjacent prefabricated standard section is directly abutted in the direction parallel to the longitudinal axis, and axial force is directly transmitted. The through is that the steel bolt penetrates through the prefabricated standard section; the non-penetration means that the steel bolt does not completely penetrate through the prefabricated standard section.

The limiting inner cylinder bolt is arranged as a cylinder body, the joint position of the prefabricated standard section is embedded in the prefabricated standard section, the outer wall of the limiting inner cylinder bolt is matched with the inner wall of the prefabricated standard section and is partially overlapped with two adjacent prefabricated standard sections respectively, the limiting inner cylinder bolt is coaxial with the prefabricated standard sections and is connected through a steel bolt arranged in the direction perpendicular to the longitudinal axis, the steel bolt penetrates through the prefabricated standard section and the limiting inner cylinder bolt or the steel bolt does not penetrate through (is called as a bolt) the prefabricated standard section and the limiting inner cylinder bolt, and the limiting inner cylinder bolt is arranged to limit dislocation or bending of the adjacent prefabricated standard sections along the longitudinal axis perpendicular to the prefabricated standard sections.

Optionally, the limiting outer cylinder bolt and the limiting inner cylinder bolt are connected with transverse ribs in a plane perpendicular to the longitudinal axis, the transverse ribs are arranged between the ends of the adjacent prefabricated standard sections, the transverse ribs can prevent the limiting outer cylinder bolt (provided with the inner transverse ribs) or the limiting inner cylinder bolt (provided with the outer transverse ribs) from sliding along the longitudinal axis, the limiting outer cylinder bolt and the limiting inner cylinder bolt have similar effects as the steel bolt, and the adjacent prefabricated standard sections transmit axial force through the transverse ribs in a direction parallel to the longitudinal axis.

The prefabricated standard section and the cylinder bolt are made of steel, concrete or steel concrete composite materials.

Optionally, the pipe wall of the pipe body of the prefabricated standard section is arranged in a lattice mode and comprises longitudinal angle steel, a transverse batten plate and end plates, bolt holes are formed in the end plates, and the end plates are connected together through bolts between the prefabricated standard section in the lattice mode.

Optionally, the assembled suspension section can be used as a stand column of a flat support independently.

Optionally, the coaxial extension section can be used as an engineering pile for vertically supporting a building or a structure.

The lattice force-bearing frame comprises centripetal longitudinal lattices parallel to the longitudinal axis and transverse lattices not parallel to the longitudinal axis: the longitudinal lattices are distributed on the periphery of the longitudinal axis in parallel, the cross section is triangular, rectangular, polygonal, trapezoidal, T-shaped, L-shaped, circular or annular, the material is a steel or steel concrete composite material, the centripetal direction means that the distance between the extension line of the long side direction of the cross section of the longitudinal lattices and the longitudinal axis is shortest, namely the width of the surface of the longitudinal lattices facing to the center of the cross section of the lattice type bearing frame is shortest; the cross lattices are connected with the vertical lattices intersected with the transverse lattices to provide stability for the vertical lattices, the cross sections of the cross lattices are rectangular or circular or T-shaped or L-shaped, and the materials are reinforcing steel bars or steel plates or section steel.

The coaxial slurry is arranged to be coaxial and concentric with the lattice type bearing frame or the coaxial expanding body assembled type support cement soil, cement body or concrete cylinder, and is made by the rotary spraying equipment which penetrates through the assembled hollow pore channel of the prefabricated standard section from the ground, namely, the high-pressure rotary sprayer sprays cement slurry, and the cement soil slurry formed after cutting and stirring the original state soil in and around the lattice type bearing frame is solidified. The tail end of the lattice type bearing frame close to the ground is called a first tail end, the tail end far away from the ground is called a second tail end, and the first tail end is connected with the suspension section or the transition section. The centripetal arrangement of the longitudinal lattices of the lattice type bearing frame reduces the blocking range of the longitudinal lattices on high-pressure injection, and increases the effective coverage range of coaxial slurry.

Furthermore, a conical end is additionally arranged at the second tail end of the lattice type bearing frame, the conical end is set to be a solid body, the front end of the conical end is sharp, and the material is steel or concrete or a steel concrete composite material.

Optionally, the tapered end is arranged in a lattice manner, and includes a solid lattice, a side wall hole and a tapered end hole, the side wall hole is arranged on the tapered surface of the lattice tapered end, and is arranged as a backflow channel of fluid (including soil slurry and cement soil slurry); the conical end hole is arranged at the conical tip of the lattice type conical end (namely the conical tip of the conical end becomes a hole) and is arranged as a jet channel of a high-pressure jet flow, and the high-pressure jet flow is high-pressure water flow or high-pressure (cement) slurry flow or air flow; the solid structure is a body or a solid body with a lattice type conical end.

Optionally, increase between lattice formula load-bearing frame and the unsettled section and set up the changeover portion, connect unsettled section and lattice formula load-bearing frame, hole bottom elevation and foundation bedplate set up the changeover portion within range, the changeover portion make by permanent body, the material is concrete, steel or steel concrete combined material.

The lattice type bearing frame and the plurality of prefabricated standard sections are directly placed in the soil body section by section through set construction equipment, or holes are led in advance through the set construction equipment at a preset position, and then the lattice type bearing frame and the plurality of standard sections are placed in the soil body section by section. In any way, the conical end of the lattice type bearing frame is a necessary arrangement for opening up a pore channel in a soil body, so that the interior of the lattice type bearing frame is hollow or partially hollow, even if soft soil or sandy soil is locally reduced in diameter or collapsed, the interior of the lattice type bearing frame is at least partially hollow, and the subsequent rotary spraying process is simpler and more effective; under the working condition of a guide hole, the conical end of the lattice type bearing frame has a guiding function, and after the construction is finished and the coaxial expansion assembled support starts to bear the load, the conical end can directly support the soil body to provide end resistance. Thus, the tapered end is a multi-functional member.

Optionally, the tapered end at the second end of the lattice type bearing frame is arranged in a lattice type, a rotary spray head of rotary spray equipment is arranged in a tapered end hole of the lattice type tapered end, high-pressure spray water flow or slurry flow (fluid) cuts a soil body in front of the lattice type tapered end through the tapered end hole, backflow slurry (fluid) flows out through a side wall hole to form a hole as a guide hole, a channel is provided for the insertion of the lattice type bearing frame and the assembled standard section, or the insertion resistance is reduced. Namely, high-pressure spraying (rotary spraying) and the arrangement of the lattice type bearing frame and the assembled standard section are carried out simultaneously, so that the work efficiency is improved. After the lattice type bearing frame and the assembled standard section are placed into the set positions, the rotary nozzle of the rotary spraying equipment begins to withdraw towards the outside of the hole, and high-pressure jet flow of cement slurry is used for cutting and stirring soil bodies in or around the lattice type bearing frame to form coaxial slurry.

The lattice type conical end is an essential component when the jet grouting equipment is used for leading holes, and has the function that the solid type conical end does not have, because the solid body of the solid type conical end blocks the soil body in front of the conical end from being cut.

Coaxial slurry, construct by conventional jet grouting stake machine and make and form, the drilling rod of jet grouting stake machine, as the rotatory power transmission component of stake machine unit head, as the transfer passage of cement thick liquid again, the drilling rod passes the cavity passageway of prefabricated standard section, reach the terminal toper end of second of lattice formula bearing frame inboard the inner space of lattice formula bearing frame begin to spout soon to high-pressure jet cutting lattice formula bearing frame original state soil body and inside residual soil body around to form the cement thick liquid with the grout stirring, form coaxial slurry after the thick liquid solidifies.

Optionally, the lattice type bearing frame and the assembled standard section are placed in the set positions, the rotary spraying equipment is placed in the hollow pore channel, the first end of the lattice type bearing frame starts to move to the second end, the rotary spraying expanding body is carried out, the lattice type bearing frame is withdrawn after the rotary spraying equipment reaches the second end, the second rotary spraying expanding body is carried out, and coaxial slurry is formed after the slurry is solidified.

Furthermore, the coaxial slurry is manufactured by a shaftless rotary sprayer. The shaftless rotary sprayer adopts the following technical scheme:

the shaftless rotary sprayer is not provided with a drill rod and a rotating shaft (shaftless drill rod is called shaftless for short), only a soft high-pressure flow transmission pipe is arranged (liquid and gas are transmitted by the flow transmission pipe and are called fluid and flow transmission together), and special power setting is not needed, namely, a rotary spraying pile machine is not arranged. The power of the rotary spraying is from the rotary power brought by the flowing direction of the fluid, namely the rotary power is from the grouting pump, and the grouting pump is necessary equipment of the conventional rotary spraying pile machine.

Compared with the conventional jet grouting pile machine, the shaftless jet grouting machine saves the jet grouting pile machine and the drill rod, and greatly reduces the construction cost; compared with the conventional rotary jet pile machine which is complicated in frequently connecting and disassembling the drill rod, the construction speed and the construction convenience of the shaftless rotary jet device are greatly improved; in addition, the flow delivery hose of the shaftless rotary sprayer can be bent, so that the shaftless rotary sprayer can finish the curve (and the channel or the path of the rotary spraying can be turned) rotary spraying construction process which cannot be finished by the conventional rotary spraying pile machine.

The shaftless rotary sprayer comprises a stator flow conveyer and a rotor sprayer which are communicated into a whole and can rotate relatively, wherein the rotor can rotate along a longitudinal axis, and the stator cannot rotate along the longitudinal axis. The longitudinal axis is the longitudinal axis of the shaftless rotary sprayer.

The stator flow transmission device is a fixed and non-rotating component, is hollow inside and is externally connected with a high-pressure flow transmission pipe, and the flow transmission pipe is used for transmitting liquid or gas and other fluids. The cross section of the stator current conveyor is in the form of square, round, polygonal and the like.

The rotor ejector has a circular cross section, is hollow inside and is provided with a flow conveying pore passage and a high-pressure jet orifice, and the rotary power of the rotor ejector is set, which comprises the following modes: the rotor ejector is internally provided with a spiral flow conveying pore channel (the internal spiral blades are the same as the spiral channels), and the rotor ejector is driven to rotate when fluid passes through; or the rotor ejector is provided with two fluid jet ports, the outflow direction of the jet ports deviates from the circle center of the circular section to the radial direction around, the jet lines of the high-pressure jet flows are parallel and symmetrically distributed on two sides of the circle center of the circular section at intervals of a set distance, and a couple formed by the recoil force of the two high-pressure jet flows drives the rotor ejector to rotate; or, the outer part of the rotor ejector is provided with inclined blades (equivalent to turbine blades) which are symmetrical relative to the longitudinal axis, namely, the outer backflow driving blades are arranged, and the backflow slurry outside the rotor ejector body drives the rotor ejector to rotate. The above-mentioned means may be used alone or in combination.

The shaftless rotary sprayer has an automatic forward function due to the forward impact action of high-pressure fluid.

Furthermore, high-pressure jet orifices of the rotor injector are arranged on the end face of the front end of the rotor injector in pairs and are arranged at preset jet angles, the direction of the high-pressure jet flow is inclined to the longitudinal axis and is intersected with the longitudinal axis, and the jet, cutting and stirring processes of the front end and the periphery can be finished simultaneously.

Furthermore, the shaftless rotary sprayer is constructed to manufacture a horizontal high-pressure jet rotary sprayer deep in the soil body for pit bottom reinforcement or pit bottom flat support of foundation pit enclosure. When a conventional rotary jet pile machine is constructed and used for manufacturing a horizontal rotary jet body, a large deep pit must be excavated to hoist the rotary jet pile machine into the pit for construction due to the unbendable drill rod, and complicated procedures such as precipitation, foundation pit support and the like are involved.

And adopt shaftless rotary sprayer, then the technology becomes extremely simple, need not precipitation and strut, only need squeeze into the soil body with vertical steel pipe or entity stake, form vertical hole (also can utilize the stake hole of engineering stake), put into a director in vertical hole, the director set up to barrel (being the body) or lattice formula (or muscle body), have the steering angle who sets for, shaftless rotary sprayer rear end connects an elastic locator, elastic locator set up to body or muscle body, be made by high elasticity steel, can bend and can keep straight again, under the assistance of director, utilize elastic locator to put into the vertical hole in the soil body and accomplish the level and turn, shaftless rotary sprayer can be under the construction preparation level to high pressure rotary sprayer.

Furthermore, the shaftless rotary sprayer is used as hole guiding equipment, or a rotary spraying anchor rod or a precast concrete engineering pile in the construction foundation pit enclosure is positioned through a rigid positioner, and a lattice type conical end is used for manufacturing high-pressure spraying hole guiding or coaxial slurry. The rigid positioner is arranged into a pipe body (the pipe body can be used for positioning measures of other processes at the same time) or a rib body (the rib body can also be used as the rib body in the anchor rod at the same time). Compared with the conventional rotary jet pile machine, the construction speed and the construction convenience of the shaftless rotary jet device are greatly improved because the drill rod does not need to be frequently installed and detached, and pile machine equipment is omitted. The rigid locator is made of steel, concrete or steel concrete composite material.

Furthermore, the rigid positioner constructed by the shaftless rotary sprayer is vertically arranged in a soil body and is used as a positioning rod of the equal-thickness cement soil wall, namely a ground positioning rod. The ground positioning rod is vertically arranged at the end part of the cement soil wall forming device and provides positioning and guiding effects for downward movement construction of the cement soil wall forming device, and the end part of the cement soil wall forming device is provided with a U-shaped end or an annular end which is clamped on the ground positioning rod to limit the position deviation of the cement soil wall forming device along the longitudinal or transverse horizontal direction.

Optionally, the ground positioning rod may be guided to the hole by the aid of other mechanical equipment, and then sunk by the aid of a shaftless rotary sprayer.

Optionally, the cement soil wall forming device adopts a mast-free wheel stirrer, the mast-free wheel stirrer adopts a suspension type wheel stirrer, and a ground positioning rod which is arranged in advance is used for positioning and guiding control.

Optionally, the soil cement wall forming device adopts a box type combined shaftless rotary sprayer, the box type combined shaftless rotary sprayer adopts a suspension type, and comprises a box type outer barrel and a group of shaftless rotary sprayer(s) arranged inside the outer barrel, the group of shaftless rotary sprayer is arranged on a horizontal direction sliding rod inside the outer barrel through a rotating shaft, can slide along the horizontal direction of the sliding rod and can rotate around the rotating shaft according to a preset angle, the horizontal direction sliding and the rotation are realized by a direction controller connected to the shaftless rotary sprayer, the direction controller is communicated with the natural ground and is controlled on the ground, and the direction controller is set as a mechanical traction rope or a fluid control pipe. The outer cylinder has multiple functions: providing a space for the shaftless rotary sprayer to move freely; ensuring and checking the cutting range of the shaftless rotary sprayer; as a base or support for a shaftless spinner. The horizontal section of the box-type outer cylinder is rectangular, circular or annular, the section sizes of the sliding rod and the rotating shaft are circular or annular, and the box-type outer cylinder, the sliding rod and the rotating shaft are made of steel.

Furthermore, the hauling ropes are symmetrically arranged on two sides of the shaftless rotary sprayer and are arranged in a closed ring shape, so that the function of adjusting the position and the spraying direction of the shaftless rotary sprayer is achieved, and the function of identifying and positioning the horizontal position of the shaftless rotary sprayer on the ground can be achieved; the fluid control pipes are symmetrically arranged on two sides of the shaftless rotary sprayer, and fluid is injected into the shaftless rotary sprayer alternately so as to control the horizontal sliding direction and the rotating direction of the shaftless rotary sprayer.

So far, the two main forms of the existing equal-thickness cement-soil wall, namely, the channel type stirring and the double-wheel stirring, have huge bodies and high-rise towers or masts, which not only make the equipment heavy and expensive, but also cause safety problems in the construction process due to the stability of the high-rise equipment, on the other hand, the equipment is difficult to be adopted when the operation space is limited under a high-voltage line or a bridge, a building and the like, and the double-wheel slotter adopts a suspended body (without masts), but has the cost three times as high as that of the double-wheel stirring equipment with masts due to a complex sensing and positioning adjusting system in the double-wheel slotter, and the cost of the original double-wheel stirring equipment is expensive. Therefore, the mast of the double-wheel stirring equipment is eliminated, the function of the ground locating rod is used for replacing the mast, and the suspended mast-free wheel stirrer (wheel stirring equipment) is adopted, so that the manufacturing cost of the double-wheel stirring equipment can be reduced, the double-wheel stirring equipment can be conveniently used for construction in a limited space, and the use convenience and the application range of the double-wheel stirring equipment are improved.

Furthermore, the shaftless rotary sprayer can be formed by injection molding of high-strength plastics, and the price is low enough to be used as a disposable product, so that the cost of the box-type combined shaftless rotary sprayer is lower than that of a mast-free wheel stirrer, and the box-type combined shaftless rotary sprayer can be left in an underground soil body even after being used for one time.

Furthermore, at least two ground positioning rods are connected into a whole to form a lattice or truss type enclosure structure, a box type combined shaftless rotary sprayer is arranged at the lower end of the enclosure structure and sinks to a preset depth together, and the box type combined shaftless rotary sprayer and the cement soil form a foundation pit enclosure wall together. The flow transmission pipe is directly communicated with the ground, or the flow transmission pipe is replaced by a ground positioning rod.

The invention discloses a construction method of a coaxial expansion assembled support, which comprises the following steps:

the first step is as follows: manufacturing a prefabricated standard section, manufacturing a lattice type bearing frame at the same time, and transporting to a construction site;

the second step is that: positioning on site, and guiding holes by using mechanical equipment at the position of the preset coaxial expansion body assembly type support;

the third step: erecting a positioning frame, connecting the lattice type bearing frame or the transition section with the first section of the prefabricated standard section, and hoisting and placing the lattice type bearing frame or the transition section into the lead hole;

the fourth step: connecting the second section of the prefabricated standard section with the first section of the prefabricated standard section, and continuously placing the second section of the prefabricated standard section into the first section of the prefabricated standard section, and repeating the steps until the second section of the prefabricated standard section reaches a preset position in the depth of the soil body;

the fifth step: and inserting a drill rod of the conventional rotary jet pile machine into a hollow pore channel of the prefabricated standard section to reach a preset depth, or placing a shaftless rotary jet device into the preset depth, and starting cement paste or water rotary jet expanding until the completion.

The invention discloses another construction method of a coaxial expansion assembly type support with a jet grouting lead hole embedded support, which comprises the following steps:

the first step is as follows: simultaneously manufacturing a prefabricated standard section and a lattice type bearing frame, and transporting to a construction site;

the second step is that: positioning on site, namely placing a lattice type bearing frame with a lattice type conical end at a set position, installing a shaftless rotary sprayer with a guide rope (a steel wire rope and the like) in a conical end hole of the conical end, penetrating a high-pressure flow delivery hose through a longitudinal pore passage in the lattice type bearing frame, and connecting the high-pressure flow delivery hose with a grouting pump;

the third step: starting a grouting pump, taking the lattice type bearing frame as a guide frame, starting high-pressure rotary spraying, and simultaneously assisting to jack the lattice type bearing frame into a soil body by mechanical equipment according to conditions;

the fourth step: when the lattice type bearing frame is about to completely enter the soil body, a first prefabricated standard section is installed and connected, jet grouting jacking is continued, and the next prefabricated standard section is sequentially and circularly installed until the embedding of all prefabricated standard sections is completed;

the fifth step: and (4) pulling the shaftless rotary sprayer to retract by using a guide rope, and continuously and rotatably spraying cement slurry in the lattice type bearing frame until the cement slurry reaches the first tail end of the lattice type bearing frame, thereby completing the construction of coaxial slurry.

The invention relates to a construction method of an equal-thickness cement-soil wall, which comprises the following steps:

the first step is as follows: arranging a positioning facility on the ground, arranging a ground positioning rod body with a shaftless rotary sprayer and a lattice type conical end at the lower end of a first section, arranging a soil body by using the shaftless rotary sprayer and ensuring the verticality, installing a second section of ground positioning rod body, and repeating the steps to finish the construction of the ground positioning rod, wherein mechanical equipment is used for guiding holes to improve the construction efficiency when necessary;

the second step is that: after two preset ground positioning rods are constructed in place, a guide groove is dug between the two preset ground positioning rods, the cement soil wall former is hung into the guide groove, and the U-shaped ends at the two ends of the wall former are clamped on the ground positioning rods;

the third step: starting the cement soil wall forming device, cutting and stirring soil bodies on the lower portion of the cement soil wall forming device to form a sinking space, lifting and continuously spraying cement slurry when the cement soil wall forming device reaches a preset depth, stirring to form a first cement soil groove, and constructing next cement soil grooves at intervals in sequence to finish a first batch of cement soil walls at intervals;

the fourth step: and pulling out the ground positioning rod, and constructing a second batch of cement-soil walls at intervals in sequence by taking the adjacent first batch of cement-soil grooves arranged at intervals as positioning and guiding grooves before the cement-soil slurry of the first batch of cement-soil walls is solidified, and repeating the steps to form the complete cement-soil walls with the same thickness.

The invention discloses another construction method of a foundation pit enclosure wall comprising an enclosure structure and an equal-thickness cement-soil wall, which comprises the following steps of:

the first step is as follows: manufacturing an integral enclosure structure comprising a plurality of ground positioning rods, and connecting the lower end of the enclosure structure with a box type combined shaftless rotary sprayer;

the second step is that: excavating a guide groove at a preset site position, putting an integral type enclosure structure, installing a guide positioning frame of the integral type enclosure structure, starting a grouting pump to start high-pressure rotary spraying water or cement soil slurry, and sinking the enclosure structure along a space cut by the box type combined shaftless rotary sprayer under the action of the dead weight of the enclosure structure or external auxiliary mechanical equipment;

the third step: and (5) the enclosure structure reaches the preset embedding depth (whether the shaftless rotary sprayer is taken out is determined according to the condition), and then the construction of the enclosure wall is completed.

Compared with the prior art, the invention has the advantages that:

1. the assembled prefabricated standard section of the coaxial expansion body assembled support can be repeatedly used, and the cost is reduced.

2. Compared with the inclined strut with the same diameter, the lattice type bearing frame enables the diameter of coaxial slurry sprayed coaxially and rotatably to be far larger than that of the prefabricated standard section, the bearing capacity of the component of the prefabricated standard section of the suspended section and the bearing capacity of the soil body of the coaxial expansion body section are simultaneously exerted to a reasonable level, the waste of materials is reduced, and the effective utilization of the materials is improved.

3. Compared with the construction of preposed cement soil, the construction process of coaxial rotary spraying is adopted for the postposition coaxial slurry, so that the longitudinal axis inosculation degree of the coaxial slurry and the lattice type bearing frame is higher, and the construction quality of the coaxial expander section is easier to ensure and improve.

4. The lattice type bearing frame and the coaxial slurry bear the weight of together, so that the material cost is reduced, the diameter of the coaxial expansion body is remarkably enlarged, the soil body bearing capacity of the coaxial expansion body section is improved at low cost, the distance of the front inclined strut is enlarged and even reaches twice as much as that of the prior art, the improvement enables the foundation pit earth excavation to be more convenient, and the point is one of the biggest defects of the front inclined strut.

5. Compared with the construction process of the conventional jet grouting pile machine, the shaftless jet grouting device saves mechanical equipment of the jet grouting pile machine, reduces construction cost, has the characteristic that the shaftless jet grouting device does not need to be provided with or provided with a jet grouting drill rod, enables the high-pressure jet grouting process to be fast and convenient, can be simply constructed and manufactured into a horizontal jet grouting cylinder with a pit bottom flat support, and brings unprecedented progress to foundation treatment and foundation pit support.

6. The shaftless rotary sprayer auxiliary pore-forming technology is utilized to place the lattice type bearing frame and the prefabricated standard section, and meanwhile, the construction of coaxial slurry is completed, so that hole guiding equipment is saved, and the construction speed and efficiency are improved.

7. The shaftless rotary sprayer is used for manufacturing the ground positioning rod, so that the cement-soil wall forming device can save the cost of equipment and can complete cement-soil wall construction under complex conditions; the box-type combined shaftless rotary sprayer can replace expensive wheel stirring equipment to construct equal-thickness cement-soil walls and can construct foundation pit enclosure walls.

Drawings

Fig. 1 is a longitudinal sectional view of the overall structure of the coaxial expansion body assembly type support of the present invention.

Fig. 2 is a longitudinal section of the overall structure of the coaxial expansion body assembly type support adopting a lattice type prefabricated standard section.

Fig. 3 is a cross-sectional view of a solid prefabricated modular segment of the present invention.

Fig. 4 is a cross-sectional view of a lattice prefabricated standard section of the present invention.

Fig. 5 is a cross-sectional view of a coaxial expander section of the present invention.

FIG. 6 is a longitudinal section of the bolt connection mode of the limiting outer cylinder of the prefabricated standard section.

FIG. 7 is a longitudinal cross-sectional view of the spacing inner barrel bolting pattern of the prefabricated modular segment of the present invention.

Fig. 8 is a longitudinal section of the shaftless swirler of the present invention provided with a spiral flow duct.

FIG. 9 is a cross-sectional view of a rotor jet with parallel offset high pressure jets in accordance with the present invention.

FIG. 10 is a longitudinal cross-sectional view of a rotor jet with an external return flow driver blade according to the present invention.

FIG. 11 is a side elevational view of a rotor injector of the present invention with an external return flow driver blade.

FIG. 12 is a side elevational view of a rotor jet with end-face parallel offset crossover high pressure jets in accordance with the present invention.

FIG. 13 is a vertical cross-sectional view of the horizontal high-pressure rotary sprayer of the invention for ground construction.

Fig. 14 is a vertical cross-sectional view of a pilot hole or construction bolt using a shaftless rotary sprayer of the present invention.

Fig. 15 is a front elevation view of the lattice tapered end of the second end of the lattice carrier of the present invention.

FIG. 16 is a longitudinal cross-sectional view showing the positional relationship between the cross-ribbed restraining barrel pin and the pre-fabricated standard segment of the present invention.

FIG. 17 is a vertical cross-sectional view of the present invention using the positioning rod for placing ground to construct cement-soil wall with equal thickness.

FIG. 18 is a horizontal cross-sectional view of a concrete wall of equal thickness constructed by using a positioning rod for placing ground according to the present invention.

FIG. 19 is a vertical sectional view of the box-type combined shaftless rotary sprayer of the present invention for constructing equal thickness cement soil wall.

Reference numerals:

1-a suspended section, 11-a prefabricated standard section, 111-longitudinal angle steel, 112-a transverse batten plate, 12-a connecting joint, 121-a limiting outer cylinder bolt, 122-a bolt, 123-a through steel bolt, 124-a transverse rib, 131-a limiting inner cylinder bolt and 14-an end plate; 2-coaxial extension section, 21-coaxial slurry, 22-transition section, 23-lattice type bearing frame, 231-longitudinal lattice and 232-transverse lattice; 24-a tapered end; 3-pit bottom soil body; 4-shaftless rotary sprayer, 41-stator flow conveyer, 411-fluid, 412-flow conveyer, 42-rotor sprayer, 421-spiral duct, 422-jet orifice, 423-external reflux driving blade, 43-high pressure jet, 44-reflux slurry and 45-rotor sprayer section center; 5-an elastic locator; 6-a guide; 7-a rigid locator; 8-lattice tapered end, 81-solid lattice, 82-side wall hole, 83-tapered end hole; 9-soil cement wall forming device, 90-box type combined shaftless rotary sprayer, 91-ground positioning rod, 92-soil cement, 931-U-shaped end, 932-box type outer cylinder, 933-sliding rod, 94-rotating shaft, 95-steering shaft and 951-direction controller.

Detailed Description

In order to clearly understand the technical contents of the present invention, the following examples are given in detail.

Referring to fig. 1 to 19, the coaxial expansion body assembly type support includes a suspension section 1 and a coaxial expansion body section 2, a transition section 22 is additionally arranged between the suspension section 1 and the coaxial expansion body section 2 as required, a pit bottom soil body 3 is arranged in the range of the transition section 22, the suspension section 1 includes a prefabricated standard section 11 and a connection joint 12, the prefabricated standard section 11 is arranged as a hollow pipe body, the connection joint 12 is arranged as a limit outer cylinder bolt 121 or a limit inner cylinder bolt 131, a bolt 122 or a through steel bolt 123 connects the prefabricated standard section 11 and the limit outer cylinder bolt 121, or the bolt 122 or the through steel bolt 123 connects the prefabricated standard section 11 and the limit inner cylinder bolt 131, or the limit outer cylinder bolt 121 and the limit inner cylinder bolt 131 are provided with a transverse rib 124 to limit the sliding of the cylinder along the longitudinal axis; optionally, the pipe wall of the pipe body of the prefabricated standard section 11 is arranged in a lattice manner, and includes a longitudinal angle steel 111, a transverse batten plate 112 and an end plate 14, the end plate 14 is provided with a bolt hole, and the lattice type prefabricated standard sections 11 are connected together through a bolt 122; the coaxial extension body section 2 comprises coaxial slurry 21 and a lattice type bearing frame 23, the lattice type bearing frame 23 comprises a centripetal longitudinal lattice 231 and a centripetal transverse lattice 232, a tapered end 24 is additionally arranged at the end of the lattice type bearing frame, the coaxial slurry 21 is made of cement, cement or concrete which is coaxial and concentric with the lattice type bearing frame 23 and is made of rotary spraying equipment which penetrates through a hollow pore of the prefabricated standard section 11.

The rotary spraying equipment adopts conventional equipment and can also adopt a shaftless rotary sprayer 4, the shaftless rotary sprayer 4 comprises a stator current conveyor 41 and a rotor sprayer 42, and the stator current conveyor 41 is externally connected with a high-pressure current conveying pipe 412. The rotor injector 42 is hollow and provided with a flow passage and a high-pressure injection port 422, and the rotation of the rotor injector 42 is provided by the following modes: a spiral duct 421 for conveying fluid is arranged inside the rotor ejector 42, and the fluid drives the rotor ejector 42 to rotate when passing through; or, the rotor injector 42 is provided with two high-pressure jet orifices 422, the jet orifices 422 deviate from the radial line of the center of circle 45 of the section of the rotor injector to the periphery, the jet lines of the two high-pressure jet flows 43 are parallel and symmetrically arranged at two sides of the center of circle 45 of the section of the rotor injector at intervals of set distance, and the rotor injector 42 is driven to rotate by a couple formed by the recoil force of the two high-pressure jet flows 43; alternatively, the rotor sprayer 42 may be externally provided with an inclined external back flow driving vane 423 that is symmetrical with respect to the longitudinal axis, and the rotor sprayer 42 may be rotated by the back flow slurry 44 outside the rotor sprayer 42.

The method is characterized in that a shaftless rotary sprayer 4 is adopted to construct a horizontal rotary spraying body on the natural ground, a guider 6 is arranged in a vertical hole constructed on the ground, the rear end of the shaftless rotary sprayer 4 is connected with an elastic positioner 5, the elastic positioner 5 is utilized to place the shaftless rotary sprayer 4 into a vertical hole in the soil body and finish horizontal turning under the assistance of the guider 6, and the shaftless rotary sprayer 4 is constructed to manufacture the horizontal rotary spraying body.

The shaftless rotary sprayer 4 is used as hole guiding equipment, or a rotary spraying anchor rod or a precast concrete engineering pile in the construction foundation pit enclosure, is positioned by the rigid positioner 7, and is used for manufacturing a high-pressure spraying hole guiding or coaxial slurry 21 by utilizing the lattice type conical end 8. The lattice type taper end 8 comprises a solid lattice 81, a side wall hole 82 and a taper end hole 83, the side wall hole 82 is arranged on the taper surface of the lattice type taper end 8, and the taper end hole 83 is arranged at the taper point of the lattice type taper end 8.

The rigid positioner 7 is vertically arranged in a soil body, is used as a positioning rod for constructing a cement soil wall with equal thickness, namely a ground positioning rod 91, is vertically arranged in a U-shaped end 931 at the end part of the cement soil wall former 9, provides positioning and guiding effects for downward movement of the cement soil wall former 9, limits the position deviation of the cement soil wall former 9 along the longitudinal or transverse horizontal direction, and stirs the construction cement soil 92.

Further, the cement soil wall forming device 9 is provided as a box type combined shaftless rotary sprayer 90, the box type combined shaftless rotary sprayer 90 comprises a box type outer cylinder 932 and a group of shaftless rotary sprayers 4 arranged inside the outer cylinder, the group of shaftless rotary sprayers 4 are arranged on a horizontal sliding rod 933 inside the box type outer cylinder 932 through a rotating shaft 94, slide horizontally along the sliding rod 933 and can rotate around the rotating shaft 94 according to a preset angle, the horizontal sliding and the rotation are realized by a direction controller 951 connected to the shaftless rotary sprayer 4, the direction controller 951 passes through the natural ground by a steering shaft 95, and the horizontal position and the spraying direction of the shaftless rotary sprayer 4 are controlled on the ground.

Example 1

The first step is as follows: manufacturing a prefabricated standard section and transporting to a construction site;

the second step is that: a concrete precast pile is driven into the position of a supported upright column to serve as an upright column pile, when the pile top of the precast pile is located at a set position at the upper part of the natural ground elevation, a limiting outer cylinder bolt or a limiting inner cylinder bolt is installed at the upper end of the precast pile, a first section of the precast standard section is hoisted and sleeved into the limiting outer cylinder bolt or sleeved on the limiting inner cylinder bolt, whether a bolt is installed or not is determined according to whether the limiting cylinder bolt is provided with a transverse rib, and a second section of the precast standard section is installed repeatedly;

the third step: constructing a first cast-in-place concrete flat support or installing an assembly type precast concrete flat support at the tail end of the upper part of the uppermost precast standard section, excavating the earthwork to a second flat support position, constructing and installing the second flat support by using a reserved steel member outside a limiting cylinder bolt as a support, and repeatedly installing the flat supports;

the fourth step: and excavating the earthwork of the foundation pit to the bottom, pouring a foundation slab, removing the bottommost horizontal brace, repeating the steps, removing the topmost horizontal brace, disassembling the prefabricated standard section of the hanging stand column, and conveying the prefabricated standard section to the next foundation pit for engineering recycling.

Example 2

The first step is as follows: making a vertical hole in a soil body or utilizing a vertical hole left by an engineering pile, placing a guider in the hole, and connecting an elastic positioner at the tail end of a shaftless rotary sprayer;

the second step is that: after the shaftless rotary sprayer and the elastic positioner pass through the guider, the elastic positioner bends towards the horizontal direction under the assistance of the guider, a high-pressure grouting pump is started, and the shaftless rotary sprayer is started to start rotary spraying;

the third step: after the shaftless rotary sprayer reaches a preset position, continuously and spirally spraying cement paste while withdrawing to form a horizontal rotary spraying body;

the fourth step: and withdrawing the elastic positioner and the shaftless rotary spraying device, taking out the guider, completing the construction, and continuing to construct the next horizontal rotary spraying body.

Example 3

The first step is as follows: digging a groove, constructing a guide hole on the wall of the groove, and connecting a rib body rigid positioner at the tail end of the shaftless rotary sprayer;

the second step is that: placing the shaftless rotary sprayer and the rib rigid positioner into the guide hole, starting a high-pressure grouting pump, and starting the shaftless rotary sprayer to start rotary spraying;

the third step: after the shaftless rotary sprayer reaches a preset position, the rib rigid positioner is kept in the hole, cement paste is continuously sprayed in a rotary mode while the rib rigid positioner is withdrawn, a horizontal rotary spraying anchor rod is formed, and the shaftless rotary sprayer can be kept in the hole according to the condition.

The assembled support and shaftless rotary sprayer provided by the invention is environment-friendly, shortens the construction period, facilitates construction, reduces the cost, improves the construction quality, has remarkable and unexpected improvements in the aspects of economy, convenience, social beneficial performance and the like compared with the prior art, has more remarkable and outstanding social benefits and economic benefits, and further promotes the industrial upgrading of foundation pit engineering.

In this specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims

1. The utility model provides a coaxial extension assembled supports, its characterized in that, coaxial extension assembled support, including unsettled section and coaxial extension section, unsettled section set up between end of a pit soil body and envelope, coaxial extension section set up under the end of a pit soil body, this coaxial extension section includes lattice formula bearing frame and coaxial slurry, lattice formula bearing frame with the longitudinal axis coincidence of coaxial slurry, coaxial extension assembled support set up to bracing or the stand of excavation supporting flat stay of excavation supporting.

2. The coaxial expansion assembled support according to claim 1, wherein the suspended section is configured as an assembled structure and comprises a reusable assembled prefabricated standard section, the prefabricated standard section is configured as a hollow pipe body, the pipe wall of the hollow pipe body is configured as a solid type or a lattice type, a pore passage extending along the longitudinal axis direction of the pipe body is arranged in the hollow pipe body, and the pore passage penetrates through the longitudinal axis of the coaxial expansion assembled support and is directly communicated with the lattice type bearing frame;

the prefabricated standard sections are in an assembly type connection mode, the assembly type connection mode is based on a limiting outer cylinder bolt or a limiting inner cylinder bolt, the limiting outer cylinder bolt is arranged as a cylinder body, the limiting outer cylinder bolt is used for wrapping the prefabricated standard sections at the joint positions of the prefabricated standard sections, the inner walls of the limiting outer cylinder bolts are matched with the outer walls of the prefabricated standard sections and are partially overlapped with the two adjacent prefabricated standard sections respectively, the limiting outer cylinder bolts are coaxial with the prefabricated standard sections and are connected through steel bolts arranged in the direction perpendicular to the longitudinal axis, and the limiting outer cylinder bolts are arranged for limiting the dislocation or bending of the adjacent prefabricated standard sections in the direction perpendicular to the longitudinal axis of the prefabricated standard sections;

the limiting inner cylinder bolt is arranged as a cylinder body, is embedded in the prefabricated standard section at the joint position of the prefabricated standard section, is matched with the inner wall of the prefabricated standard section at the outer wall and is partially overlapped with two adjacent prefabricated standard sections respectively, is coaxial with the prefabricated standard section and is connected with the prefabricated standard section through a steel bolt arranged in the direction vertical to the longitudinal axis, and is arranged for limiting the dislocation or bending of the adjacent prefabricated standard sections in the direction vertical to the longitudinal axis of the prefabricated standard section;

the limiting outer cylinder bolt and the limiting inner cylinder bolt are connected with transverse ribs in a plane vertical to the longitudinal axis, the transverse ribs are arranged between the end parts of the adjacent prefabricated standard sections, and the transverse ribs prevent the limiting outer cylinder bolt or the limiting inner cylinder bolt from sliding along the direction of the longitudinal axis;

the coaxial extension section is independently used as an engineering pile for supporting a building or a structure.

3. The coaxial expansion assembled support of claim 1, wherein the lattice-type force-bearing frame comprises centripetal longitudinal lattices parallel to the longitudinal axis and transverse lattices not parallel to the longitudinal axis, the longitudinal lattices are distributed in parallel on the periphery of the longitudinal axis, the transverse lattices are connected with the intersecting longitudinal lattices to provide stability for the longitudinal lattices, and the centripetal arrangement of the longitudinal lattices reduces the obstruction of the longitudinal lattices on high-pressure jet and increases the effective coverage range of the coaxial slurry.

The lattice type force-bearing frame comprises a first tail end and a second tail end, the first tail end is connected with a suspension section or a transition section, a conical end is additionally arranged at the second tail end, the transition section is arranged between the prefabricated standard section and the lattice type force-bearing frame, and the conical end is arranged as an entity; or the tapered end is arranged in a lattice type and comprises a solid lattice, a side wall hole and a tapered end hole, the side wall hole is arranged on the tapered surface of the lattice type tapered end and is used as a backflow channel of fluid, and the tapered end hole is arranged at the tapered tip of the lattice type tapered end and is used as a jet channel of high-pressure jet flow;

the coaxial slurry is set to be cement soil or cement body coaxial with the lattice type bearing frame, and is formed by solidifying cement soil slurry formed by cutting and stirring the soil body inside and around the lattice type bearing frame by high-pressure jet flow sprayed by the rotary spraying equipment penetrating through the hollow pore canal of the prefabricated standard section; the coaxial slurry is constructed and manufactured by a rotary jet pile machine or a shaftless rotary jet device.

4. The coaxial expansion fabricated support of claim 3, wherein the shaftless jet aerator is of a structure without a drill rod and a jet aerator, and the tail end of the shaftless jet aerator is connected with a flow delivery hose, the flow direction of the fluid is utilized to bring the rotating power of the shaftless jet aerator, and the shaftless jet aerator automatically moves forwards under the action of the forward impulse force of the high-pressure fluid, and is used for hole guiding or jet aerator construction.

5. The construction method of the coaxial expansion body assembly type support as claimed in any one of claims 1 to 4, wherein the construction method comprises the following steps:

the fifth step: and inserting a drill rod of the conventional rotary jet pile machine into a hollow pore channel of the prefabricated standard section to reach a preset depth, or placing a shaftless rotary jet device into the preset depth, and starting cement slurry rotary jet expansion until the cement slurry rotary jet expansion is completed.

6. The construction method of the coaxial expansion body assembly type support as claimed in any one of claims 1 to 4, wherein the construction method comprises the following steps:

the second step is that: positioning on site, namely placing a lattice type bearing frame with a lattice type conical end at a set position, installing a shaftless rotary sprayer with a guide rope in a conical end hole of the conical end, and penetrating a high-pressure flow delivery hose through an inner pore passage of the lattice type bearing frame and connecting the high-pressure flow delivery hose with an injection pump;

the third step: starting a grouting pump, taking the lattice type bearing frame as a guide frame, starting high-pressure jet grouting of a pilot hole, and simultaneously assisting to press the lattice type bearing frame into a soil body by mechanical equipment according to conditions;

the fourth step: when the lattice type bearing frame is about to completely enter the soil body, installing and connecting a transition section or a first prefabricated standard section, continuing jet grouting jacking, and sequentially and circularly installing the next prefabricated standard section until the embedding of all prefabricated standard sections is completed;

7. The construction method of the coaxial expansion body assembly type support as claimed in any one of claims 1 to 2, wherein the suspended section is used for a vertical column of a foundation pit flat support, and the construction method comprises the following steps:

the second step is that: a concrete precast pile is driven into the position of a supported upright column to serve as an upright column pile, when the pile top of the precast pile is located at a set position at the upper part of the natural ground elevation, a limiting outer cylinder bolt or a limiting inner cylinder bolt is installed at the upper end of the precast pile, a first section of the precast standard section is hoisted and sleeved into the limiting outer cylinder bolt or sleeved on the limiting inner cylinder bolt, whether the bolt is installed or not is determined according to the existence of a transverse rib of the limiting cylinder bolt, and a second section of the precast standard section is installed repeatedly according to the determination;

the fourth step: and excavating the earthwork of the foundation pit to the bottom, pouring a foundation slab, removing the bottommost horizontal brace, repeating the steps until the topmost horizontal brace is removed, disassembling the prefabricated standard section with the column lifted away, and conveying the prefabricated standard section to the next foundation pit project for recycling.

8. The shaftless rotary sprayer is characterized by comprising a stator flow conveyer and a rotor sprayer, wherein the stator flow conveyer and the rotor sprayer are communicated into a whole and can rotate relatively, the rotor sprayer is arranged to rotate along a longitudinal axis, and the stator flow conveyer is arranged not to rotate along the longitudinal axis; the stator current conveyor is hollow inside and is externally connected with a high-pressure current conveying pipe; the cross section of the rotor ejector is circular, the rotor ejector is hollow and is provided with a flow conveying pore passage and a fluid ejection opening;

the rotary power of the rotor ejector is set as follows: a spiral flow conveying channel is arranged in the rotor ejector, and fluid drives the rotor ejector to rotate when passing through the spiral flow conveying channel; alternatively, the first and second electrodes may be,

the rotary power of the rotor ejector is set as follows: the rotor ejector is provided with two fluid jet ports, the outflow direction of the jet ports deviates from the circle center of the circular section to the radial direction around, the jet lines of the high-pressure jet flows are parallel and symmetrically distributed on two sides of the circle center of the circular section at intervals of a set distance, and the rotor ejector is driven to rotate by a couple formed by the recoil force of the two high-pressure jet flows; alternatively, the first and second electrodes may be,

the rotary power of the rotor ejector is set as follows: the external reflux driving blades which are symmetrical relative to the longitudinal axis and inclined are arranged outside the rotor ejector, and the rotor ejector is driven to rotate by virtue of the reflux slurry outside the rotor ejector;

the shaftless rotary sprayer is of a structure of a shaftless, drillpipe-free and rotary spraying pile machine, the tail end of the shaftless rotary sprayer is connected with a high-pressure flow delivery hose, rotary spraying power is derived from rotary power brought by the flow direction setting of fluid, and the shaftless rotary sprayer has an automatic forward function and is used for hole leading or rotary spraying body construction of a linear path or rotary spraying construction process of a curved path which cannot be completed by a conventional rotary spraying pile machine.

9. The shaftless rotary sprayer according to claim 8, wherein the shaftless rotary sprayer is used in groups to form a box type combined shaftless rotary sprayer used as a cement soil wall forming device, the box type combined shaftless rotary sprayer is of a suspension type and comprises a box type outer barrel and a group of shaftless rotary sprayers arranged in the box type outer barrel, the group of shaftless rotary sprayers are arranged on a horizontal sliding rod in the outer barrel through a rotating shaft, slide horizontally along the sliding rod and rotate around the rotating shaft according to a preset angle;

the horizontal sliding and rotation are realized by a direction controller connected to the shaftless rotary sprayer, and the direction controller is a mechanical traction rope or a fluid control pipe; the box-type outer cylinder is used as a base or a bracket of the shaftless rotary sprayer, provides a moving space for the shaftless rotary sprayer, and ensures and checks the cutting range of the shaftless rotary sprayer;

the hauling ropes are symmetrically arranged on two sides of the shaftless rotary sprayer, and the horizontal position and the spraying direction of the shaftless rotary sprayer are adjusted; the fluid control pipes are symmetrically arranged on two sides of the shaftless rotary sprayer, and fluid is injected into the shaftless rotary sprayer alternately so as to control the horizontal sliding direction and the rotating direction of the shaftless rotary sprayer.

10. A construction method using the shaftless rotary sprayer of claim 8, for constructing a horizontal rotary sprayer installed deep in a soil body, comprising the steps of:

11. A construction method using the shaftless rotary sprayer of claim 8, for constructing a cement-soil wall of an equal thickness, said construction method comprising the steps of:

the first step is as follows: arranging a positioning facility on the ground, arranging a ground positioning rod body with a shaftless rotary sprayer and a lattice type conical end at the lower end of a first section, utilizing a guide hole of the shaftless rotary sprayer to insert a soil body and ensuring the verticality, installing a second section of ground positioning rod body, and repeating the steps to complete the construction of the ground positioning rod, wherein mechanical equipment can be used for guiding the hole to improve the construction efficiency when necessary;

the second step is that: after two preset ground positioning rods are constructed in place, a guide groove is dug between the two preset ground positioning rods, the cemented soil wall forming device is hung into the guide groove, and the U-shaped ends at the two ends of the cemented soil wall forming device are clamped on the ground positioning rods;

12. A method of constructing a foundation pit enclosure comprising a building envelope and a cementitous wall of equal thickness using the shaftless jet grouting apparatus of claim 8, said method comprising the steps of:

the first step is as follows: manufacturing an integral enclosure structure comprising a plurality of ground positioning rods, and connecting a box type combined shaftless rotary sprayer at the lower end of the enclosure structure, wherein a flow transmission pipe of the box type combined shaftless rotary sprayer is directly communicated with the ground or is replaced by the ground positioning rods;

the second step is that: excavating a guide groove at a preset site position, placing an integral enclosure structure, installing a guide positioning frame of the integral enclosure structure, starting a grouting pump to start high-pressure rotary spraying water or cement soil slurry, and sinking the enclosure structure along a space cut by the box type combined shaftless rotary sprayer under the action of the dead weight of the enclosure structure or external auxiliary mechanical equipment;

the third step: and the building enclosure reaches the preset embedding depth, and the construction of the building enclosure is finished.