Construction method of ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting

Abstract

The invention discloses an ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method, belonging to the technical field of ultra-low clearance rotary jet grouting. The construction method of the present invention is completed by the cooperation of a drilling rig with a multi-axis mechanical arm, a power head assembly, a sliding mast assembly, a hole-opening drill tool and a rotary jet drilling tool, as well as a high-pressure grouting pump, an air compressor and a ground recovery device, and includes the steps of moving and assembling the rotary jet grouting equipment in a limited micro space, opening a hole in a surface hard shell layer and the rotary jet grouting construction steps. The rotary jet grouting equipment makes the power head and the sliding mast detachable, and the multi-axis mechanical arm design is used to achieve the purpose of flexible movement in a limited micro space and operation in a narrow and tortuous space; during the construction process, a hole is first opened in the surface hard shell layer and then the rotary jet grouting is performed, and during the rotary jet grouting process, a multi-level double-channel rotary jet nozzle is used to realize high-pressure spraying at multiple levels, thereby doubling the construction efficiency and improving the pile quality; at the same time, the vacuum back-suction device can adaptively adjust the opening amplitude of the back-suction hole, and a wireless pressure sensor is used to monitor the bottom hole pressure in real time. No manual intervention is required during the entire rotary jetting process, the construction operation is simpler and more convenient, and the construction cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to a rotary jet grouting device and a construction method thereof, and more specifically to an ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method. Background Art

[0002] The ultra-low clearance high-pressure jet grouting construction method was developed to address the technical challenges encountered when reinforcing or renovating foundations in urban underground spaces or under existing buildings where space is limited. This method allows construction in basements, tunnels, and other low-clearance environments, but faces a series of technical and operational challenges, especially in terms of the applicability of construction equipment, construction efficiency, and cost-effectiveness.

[0003] Technical complexity: Ultra-low clearance construction requires sophisticated equipment and a high degree of technical precision. High-pressure jet grouting technology requires very precise operation, including pressure control of concrete or other injected materials and precise control of injection position. These technical complexities require special design of construction equipment, increasing equipment cost and maintenance difficulty.

[0004] Cost issue: Compared with conventional construction, ultra-low clearance high-pressure jet grouting equipment and its operation have higher costs. The particularity of the equipment requires higher procurement and maintenance costs, and the training of operators also requires more professionalism, which increases the overall construction cost.

[0005] Environmental and safety risks: When ultra-low clearance construction is carried out in a dense urban environment, the vibration and noise caused by the construction may affect surrounding buildings and residents. In addition, improper operation during high-pressure jet spraying may cause safety accidents, such as uncontrolled material spraying.

[0006] Operational limitations: In extreme space conditions, the construction team needs to precisely control the construction process while ensuring safety. The physical limitations in this environment make mechanical operation more difficult, thus affecting construction efficiency and quality.

[0007] Specifically:

[0008] First, the construction equipment cannot complete the construction in a small space, especially some tortuous spaces: high-pressure jet grouting equipment is usually designed as a larger mechanical unit to maintain the required construction capacity and stability, which results in their limited operation in very narrow or tortuous spaces. For example, although some equipment mentioned in the prior art can work in a certain low-headroom environment, for those complex underground structures or foundations of old buildings, such as underground pipeline networks or limited basement passages, the large size and operating radius of the equipment limit its flexibility. In these environments, traditional jet grouting equipment may not be able to enter or rotate, and thus cannot complete the intended reinforcement work.

[0009] Second, construction equipment cannot pass through low passages: Since construction equipment usually has a tall body and complex equipment structure, they face challenges when they need to pass through low passages or door openings. Even equipment designed for ultra-low clearance often needs to be disassembled or partially disassembled before entering the construction site, which not only increases the amount of preparation work before construction, but may also affect the function and stability of the equipment due to reassembly.

[0010] Third, the construction equipment is not efficient: Although high-pressure jet grouting can theoretically quickly complete foundation treatment, in actual operation, due to the limited mobility of the equipment in narrow spaces and the need to frequently adjust the equipment position to adapt to the needs of complex terrain, its construction speed is often lower than expected. In addition, the preparation time for high-pressure jet grouting is long, including the installation and commissioning of equipment and the preparation of spraying materials, which further reduces the overall construction efficiency.

[0011] Fourth, although construction equipment such as MJS (Mechanical Jetting System) has micro-disturbance function, it has the disadvantages of manual identification of operation errors and high cost: Modern high-pressure rotary grouting equipment such as micro-disturbance jetting system (MJS) can reinforce the foundation without destroying the original surrounding soil structure, which is a major technological advancement in theory. However, this system relies on the operator's accurate judgment of geological conditions and jetting effects, and any error may lead to construction quality problems. In addition, the cost of this high-end equipment is very high, including purchase, maintenance and operation training costs, which largely limits its widespread application.

[0012] In summary, although the ultra-low clearance high-pressure rotary grouting construction technology provides a possible solution for urban underground projects, there are still many problems that need to be overcome in terms of equipment adaptability, construction efficiency, operation accuracy and cost control. Summary of the invention

[0013] 1. Technical problem to be solved by the invention

[0014] The purpose of the present invention is to provide an ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method to solve the problems of the existing rotary jet grouting process being difficult to construct in a narrow and tortuous space, having low construction efficiency, being greatly affected by manual operation errors in construction quality, and having high construction costs. The technical scheme of the present invention is adopted, and the rotary jet grouting equipment is optimized to make the power head and the sliding mast detachable, and the foldable multi-axis mechanical arm design is utilized, and the multi-axis mechanical arm can be folded to realize flexible movement in a limited micro space, thereby realizing the purpose of flexible hole opening and rotary jet grouting in a narrow and tortuous space; during the construction process, the power head and the sliding mast are detachable, and the foldable multi-axis mechanical arm is folded to realize flexible movement in a limited micro space, thereby realizing the purpose of flexible hole opening and rotary jet grouting in a narrow and tortuous space; during the construction process, the power head and the sliding mast are detachable, and the power head and the sliding mast are detachable, and the foldable multi-axis mechanical arm is folded to realize flexible movement in a limited micro space, and the foldable multi-axis mechanical arm is folded to realize flexible hole opening and rotary jet grouting in a narrow and tortuous space; during the construction process, ... Holes are opened in the surface hard shell layer and then rotary jet grouting is carried out. During the rotary jet grouting process, multi-level dual-channel rotary jet nozzles are used to achieve high-pressure jetting at multi-level points, which doubles the construction efficiency and improves the quality of piles. At the same time, the innovatively designed vacuum back-suction device can adaptively adjust the opening amplitude of the back-suction hole, and use a wireless pressure sensor to monitor the bottom hole pressure in real time. When the bottom hole pressure exceeds the design pressure, the vacuum back-suction pipeline is opened for suction. No human intervention is required during the entire rotary jet process, which avoids quality problems caused by human operating errors. The construction operation is simpler and more convenient, and the construction cost is greatly reduced.

[0015] 2. Technical solution

[0016] In order to achieve the above object, the technical solution provided by the present invention is:

[0017] The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention comprises the following construction steps:

[0018] S1. Movement and assembly of rotary jet grouting equipment in a limited micro space:

[0019] The rotary jet grouting equipment includes a drilling rig, a power head assembly, a sliding mast assembly, a hole drilling tool and a rotary jet drilling tool. The drilling rig is provided with a foldable multi-axis mechanical arm, which is operated to fold the multi-axis mechanical arm to reduce the overall height of the drilling rig, and to control the drilling rig to move through a low passage to enter a position where rotary jet grouting is required;

[0020] After the drilling rig moves to the designated location, the multi-axis mechanical arm is controlled to extend to the position to be constructed, and the sliding mast assembly is installed at the free end of the multi-axis mechanical arm, and the power head assembly is installed on the sliding mast assembly; at the same time, the high-pressure grouting pump, air compressor and ground recovery device are put into place;

[0021] S2, opening of the surface hard shell layer:

[0022] Install a rotary jet flow divider on the power head assembly, install a hole drilling tool on the rotary jet flow divider, and connect an air compressor pipeline and a vacuum return suction pipeline;

[0023] The power head assembly drives the drilling tool to perform drilling operations on the surface hard shell layer. The drilling tool rotates while drilling, and at the same time, the air compressor pipeline is used to give the drilling tool impact power, and the debris at the bottom of the hole is sucked to the ground recovery device through the vacuum suction pipeline; after the drilling operation, the drilling tool is lifted by the sliding mast assembly, and the drilling tool is disassembled;

[0024] S3, rotary jet grouting construction:

[0025] A jet grouting drill is installed on the jet grouting diverter, the jet grouting drill includes a jet grouting drill rod, a vacuum suction device and a drill bit which are arranged in sequence, a high-pressure polymer interface of the jet grouting diverter is connected to a corresponding high-pressure grouting pump, and a compressed air interface of the jet grouting diverter is connected to an air compressor; and then a test jet is performed to check the safety of each pipeline and the size of the jet pressure;

[0026] After the test jetting is completed, normal drilling is carried out and an extended drill rod is added to reach the designed pile bottom elevation;

[0027] The backstage loads materials according to the design ratio, starts the high-pressure grouting pump and air compressor in sequence, and delivers polymer and compressed air to the multi-level dual-channel jet nozzle at the bottom of the jet drill rod, and performs multi-level high-pressure jetting and stirring of the soil to form piles; at the same time, the jet drill tool is gradually lifted according to the designed lifting speed; after completing a stroke, a section of the extended drill rod is removed, and multi-level high-pressure jetting is continued until the designed pile top elevation is reached;

[0028] During the rotary jet grouting process, the wireless pressure sensor in the vacuum back-suction device monitors the bottom hole pressure in real time. When the bottom hole pressure exceeds the design pressure, the vacuum back-suction pipeline is opened for suction. At the same time, the sealing plunger in the vacuum back-suction device adaptively opens the multi-layer back-suction holes under the action of the bottom hole pressure, and sucks the high-pressure polymer mixture at the bottom of the hole to the ground recovery device.

[0029] Furthermore, the multi-axis robotic arm includes a large power arm, an intermediate power arm and a retractable hydraulic power arm. The lower end of the large power arm is movably mounted on a turntable, and the turntable is mounted on the crawler chassis of the drilling rig, so that the multi-axis robotic arm can rotate as a whole; one end of the intermediate power arm is movably mounted on the upper end of the large power arm, and the other end of the intermediate power arm is movably connected to the retractable hydraulic power arm to form a six-axis rotatable retractable power arm.

[0030] Furthermore, a hydraulic oil pump assembly, a control console and an electrical assembly are also installed on the crawler chassis of the drilling rig, and the vacuum back-suction pipeline also includes a hydraulic vacuum back-suction pump installed on the crawler chassis. The hydraulic vacuum back-suction pump, the hydraulic oil pump assembly, the control console and the electrical assembly are distributed around the crawler chassis to form a space in the middle of the crawler chassis for folding a multi-axis mechanical arm. The multi-axis mechanical arm is folded on the crawler chassis to enable the drilling rig to pass through a low passage.

[0031] Furthermore, the rotary jet diverter includes a diverter shell and a rotating shaft body that can rotate freely in the diverter shell, the rotating shaft body can be installed on the power head assembly, and the power head assembly drives the rotating shaft body to rotate; the rotary jet drill rod is provided with a vacuum back-suction channel, a high-pressure polymer channel and a high-pressure gas channel, the vacuum back-suction channel is connected to the vacuum back-suction interface on the diverter shell, and the vacuum back-suction interface is connected to the vacuum back-suction pipeline; the high-pressure polymer channel is connected to the high-pressure polymer interface on the diverter shell; the high-pressure gas channel is connected to the compressed air interface on the diverter shell; the dual-channel rotary jet nozzle is axially spaced at least two groups at the lower part of the rotary jet drill rod, and each group of the dual-channel rotary jet nozzles includes a high-pressure polymer A nozzle and a high-pressure gas nozzle located on the periphery of the high-pressure polymer nozzle, the high-pressure polymer nozzle is connected to the corresponding high-pressure polymer channel, and the high-pressure gas nozzle is connected to the corresponding high-pressure gas channel; the vacuum back-suction device has a multi-layer back-suction hole connected to the vacuum back-suction channel of the rotary jet drill pipe, and the vacuum back-suction device is provided with a wireless pressure sensor, a high-strength spring and a sealing plunger from top to bottom, a back-suction port is provided below the sealing plunger, the sealing plunger is sealed with the multi-layer back-suction hole, and the sealing plunger can move up and down according to the change in the pressure of the polymer mixture in the ground to control the opening and closing and the opening amplitude of the multi-layer back-suction hole; the wireless pressure sensor is communicatively connected to the ground mechanical equipment operating platform to control the start or close of the vacuum back-suction pipeline.

[0032] Furthermore, the suction port is arranged at the lower end of the rod body of the vacuum suction device, and a spiral adjuster is connected to the inner thread of the suction port. The spiral adjuster has a central through hole, and the upper end of the spiral adjuster abuts against the lower end surface of the sealing plunger. The spiral adjuster also has a screwing structure for facilitating the adjustment operation.

[0033] Furthermore, the vacuum back-suction channel is located at the center of the rotary jet drill rod, the high-pressure gas channel is located at the outermost side of the rotary jet drill rod, and the high-pressure polymer channel is located between the vacuum back-suction channel and the high-pressure gas channel; the lower end of the rotary jet drill rod has a junction block for sealing the corresponding high-pressure polymer channel and the high-pressure gas channel, and the junction block is provided with a junction ring groove connected to the corresponding channel, the high-pressure polymer nozzle is respectively connected to the junction ring groove corresponding to the corresponding high-pressure polymer channel, and the high-pressure gas nozzle is respectively connected to the high-pressure gas channel or the junction ring groove corresponding to the high-pressure gas channel.

[0034] Furthermore, the upper end of the rotating shaft body has a stepped rotating joint, and a plurality of channels are correspondingly arranged on the stepped surface of the stepped rotating joint. The diverter housing has a stepped cavity adapted to the above-mentioned stepped rotating joint, and the step surface of the stepped cavity is provided with a diverter groove corresponding to the corresponding channel, and the vacuum back-suction interface, the high-pressure polymer interface and the compressed air interface are respectively connected to the corresponding diverter grooves; the step side walls of the stepped rotating joint are also respectively provided with sealing steel rings that seal with the inner side walls of the stepped cavity.

[0035] Furthermore, the lower end of the rotating shaft body has a diverter joint for connecting an extended drill rod or a rotary jet drill rod, and the two ends of the extended drill rod are respectively provided with an extended drill rod upper joint and an extended drill rod lower joint, and the upper end of the rotary jet drill rod is provided with a rotary jet drill rod upper joint. The diverter joint is complementary in shape to the extended drill rod upper joint and the rotary jet drill rod upper joint, and the extended drill rod lower joint is complementary in shape to the rotary jet drill rod upper joint, and the diverter joint, the extended drill rod upper joint, the extended drill rod lower joint and the rotary jet drill rod upper joint all adopt a stepped butt joint structure.

[0036] Furthermore, the hole-opening drilling tool includes a common drill rod and a down-the-hole hammer drill bit, the upper end of the common drill rod is connected to the rotary jet diverter, and the down-the-hole hammer drill bit is fixed to the lower end of the common drill rod, and the center of the common drill rod and the down-the-hole hammer drill bit both have a debris suction channel.

[0037] Furthermore, a plurality of stirring blades are provided on the outer wall of the rotary jet drilling rod.

[0038] 3. Beneficial effects

[0039] Compared with the existing known technologies, the technical solution provided by the present invention has the following significant effects:

[0040] (1) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention makes the power head and the sliding mast detachable through the optimized design of the rotary jet grouting equipment, and utilizes the foldable multi-axis mechanical arm design. After the multi-axis mechanical arm is folded, it can realize flexible movement in the limited micro-space, thereby realizing the purpose of flexible hole opening and rotary jet grouting in a narrow and tortuous space; during the construction process, a hole is first opened in the surface hard shell layer and then rotary jet grouting is performed. During the rotary jet grouting process, a multi-level double-channel rotary jet nozzle is used to realize high-pressure spraying at multiple levels, thereby doubling the construction efficiency and improving the pile quality; at the same time, the vacuum back-suction device with innovative design can adaptively adjust the opening amplitude of the back-suction hole, and use a wireless pressure sensor to monitor the bottom hole pressure in real time. When the bottom hole pressure exceeds the design pressure, the vacuum back-suction pipeline is opened for suction. No manual intervention is required during the entire rotary jet process, thereby avoiding quality problems caused by manual operation errors, making the construction operation simpler and more convenient, and greatly reducing the construction cost.

[0041] (2) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention comprises a multi-axis mechanical arm including a large power arm, an intermediate power arm and a retractable hydraulic power arm. The lower end of the large power arm is movably mounted on a turntable, and the turntable is mounted on the crawler chassis of the drilling rig, so that the multi-axis mechanical arm can rotate as a whole; one end of the intermediate power arm is movably mounted on the upper end of the large power arm, and the other end of the intermediate power arm is movably connected to the retractable hydraulic power arm to form a six-axis rotatable retractable power arm; the multi-axis mechanical arm has a compact structure after folding and occupies a small space, so that the drilling rig can pass smoothly in a low passage, and the multi-axis mechanical arm has a high degree of freedom and can adapt to complex and tiny spaces, ensuring that the power head and the drilling tool can be extended into a limited tortuous space for rotary jet grouting construction, and has the advantages of flexible movement, diverse application scenarios, and convenient construction in a limited space.

[0042] (3) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention is characterized in that a hydraulic oil pump assembly, a control console and an electrical assembly are also installed on the crawler chassis of the drilling rig, and the vacuum return suction pipeline also includes a hydraulic vacuum return suction pump installed on the crawler chassis. The hydraulic vacuum return suction pump, the hydraulic oil pump assembly, the control console and the electrical assembly are distributed around the crawler chassis to form a space for the multi-axis mechanical arm to fold in the middle of the crawler chassis. The multi-axis mechanical arm is folded on the crawler chassis to enable the drilling rig to pass through a low passage. By adopting this drilling rig structural layout, the overall height of the drilling rig is effectively reduced after the multi-axis mechanical arm is folded, and the multi-axis mechanical arm, the hydraulic vacuum return suction pump, the hydraulic oil pump assembly, the control console and the electrical assembly are integrated and installed on the crawler chassis. The structure is simple and compact, and the operation is convenient, which ensures that the drilling rig can be flexibly moved and rotated in ultra-low clearance scenarios.

[0043] (4) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention comprises a rotary jet diverter including a diverter housing and a rotating shaft body that can rotate freely in the diverter housing. The rotary jet drill pipe has a vacuum back-suction channel, a high-pressure polymer channel and a high-pressure gas channel. A multi-channel high-pressure rotary jet diverter is combined with a multi-level high-pressure jet rotary jet drill pipe, so that the lower part of the rotary jet drill pipe uses multiple dual-channel rotary jet nozzles to achieve multi-level points for high-pressure jetting, which greatly improves the construction efficiency and pile quality. Each group of dual-channel rotary jet nozzles includes a high-pressure polymer nozzle and a high-pressure gas nozzle located on the periphery of the high-pressure polymer nozzle. The high-pressure polymer is sprayed from the center, and the high-pressure gas surrounds the high-pressure polymer jet and is sprayed together, which plays a protective role. The high-pressure strength of the high-pressure polymer jet ensures that the high-pressure jet cuts the soil more effectively; the wireless pressure sensor, high-strength spring and sealing plunger are arranged in the vacuum back-suction device from top to bottom. The sealing plunger can move with the increase of pressure, thereby opening the annular multi-layer back-suction hole, and the polymer mixture at the bottom of the hole is transported to the ground recovery device along the multi-layer back-suction hole under the suction of the vacuum pump, which automatically realizes the effect of increasing the high-pressure reflux channel and realizes the adaptive control of the bottom hole pressure, avoiding the problem of squeezing and disturbance of the surrounding soil due to excessive bottom hole pressure, and realizing the dynamic adjustment of the pressure in the hole; and no longer relying on imported MJS equipment, the construction cost of micro-disturbance rotary jet grouting is greatly reduced, which can be widely used.

[0044] (5) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention has a suction port arranged at the lower end of the rod body of the vacuum suction device, and a spiral regulator is threadedly connected to the suction port. The spiral regulator has a central through hole, and the upper end of the spiral regulator is abutted against the lower end surface of the sealing plunger. The spiral regulator also has a screw structure that is convenient for adjustment operation. The minimum in-hole pressure can be adjusted by the spiral regulator, which is convenient for accurate control of the in-hole construction pressure and ensuring the quality of pile formation.

[0045] (6) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention has a vacuum back-suction channel located at the center of the rotary jet drill rod, a high-pressure gas channel located at the outermost side of the rotary jet drill rod, and a high-pressure polymer channel located between the vacuum back-suction channel and the high-pressure gas channel. In this way, the size of the vacuum back-suction channel can be designed to be larger, the back-suction flow rate is larger and smoother, and it is convenient to set up multiple dual-channel rotary jet nozzles, and to connect the high-pressure gas channel and the high-pressure polymer channel with the dual-channel rotary jet nozzle, so as to facilitate the production of the rotary jet drill rod; in addition, the lower end of the rotary jet drill rod has a sealing A confluence block is provided for blocking the corresponding high-pressure polymer channel and the high-pressure gas channel, and a confluence ring groove connected with the corresponding channel is provided on the confluence block. The high-pressure polymer nozzle is respectively connected with the confluence ring groove corresponding to the corresponding high-pressure polymer channel, and the high-pressure gas nozzle is respectively connected with the high-pressure gas channel or the confluence ring groove corresponding to the high-pressure gas channel. With this design, the confluence of various channels in the rotary jet drill pipe can be achieved, the injection pressure of the dual-channel rotary jet nozzle can be ensured, and efficient cutting and mixing of the soil can be achieved. At the same time, the confluence block is used for assembly and sealing, the structure is simple, and the difficulty of making the internal channel of the rotary jet drill pipe is reduced.

[0046] (7) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention has a stepped rotary joint at the upper end of the rotating shaft body, and a plurality of channels are correspondingly arranged on the stepped surface of the stepped rotary joint. The diverter housing has a stepped cavity adapted to the above-mentioned stepped rotary joint, and a diverter groove corresponding to the corresponding channel is arranged on the step surface of the stepped cavity, and a vacuum back-suction interface, a high-pressure polymer interface and a compressed air interface are respectively connected to the corresponding diverter groove; the above-mentioned stepped rotary joint structure is adopted, which can not only realize the uniform diversion of each channel, but also facilitate the sealing assembly between each channel, so that the rotary jet diverter is more convenient to manufacture, and the number of channels can be increased or decreased according to the design requirements, thereby realizing the multi-channel high-pressure rotary jet diversion effect of the drilling tool; in addition, the step side walls of the stepped rotary joint are respectively provided with sealing steel rings that are sealed with the inner side walls of the stepped cavity, thereby ensuring the effective isolation and rotary sealing between each channel.

[0047] (8) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention has a diverter joint for connecting an extended drill rod or a rotary jet drill rod at the lower end of the rotating shaft body, and the two ends of the extended drill rod are respectively provided with an extended drill rod upper joint and an extended drill rod lower joint, and the upper end of the rotary jet drill rod is provided with a rotary jet drill rod upper joint, and the diverter joint is complementary in shape to the extended drill rod upper joint and the rotary jet drill rod upper joint, and the extended drill rod lower joint is complementary in shape to the rotary jet drill rod upper joint, and the diverter joint, the extended drill rod upper joint, and the extended drill rod upper joint are complementary in shape to the rotary jet drill rod upper joint, and the diverter joint, the extended drill rod upper joint, and the extended drill rod lower joint are complementary in shape to the rotary jet drill rod upper joint, and the diverter joint, the extended drill rod upper joint, and the extended drill rod upper joint are respectively provided with an extended drill rod upper joint and an extended drill rod lower joint, and the extended drill rod upper joint is provided with an extended drill rod upper joint. Both the lower joint of the rod and the upper joint of the rotary jet drill rod adopt a stepped butt joint structure; the above design can facilitate the assembly of the rotary jet diverter, the extended drill rod and the rotary jet drill rod, and the stepped butt joint structure design can facilitate the connection and sealing of each channel, ensure the independence of each channel in the rotary jet drill, and can effectively avoid the blockage of the channel and the nozzle, thereby ensuring the stability and reliability of the rotary jet drill during the construction process; at the same time, the stepped butt joint design has high connection strength and good coaxiality of the drill, which can further improve the construction stability of the drill.

[0048] (9) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention, wherein the hole-opening drilling tool comprises an ordinary drill rod and a down-the-hole hammer drill bit, has the advantages of high hole-opening efficiency, long service life, and low construction cost; the down-the-hole hammer drill bit is fixed at the lower end of the ordinary drill rod, and the center of the ordinary drill rod and the down-the-hole hammer drill bit both have a debris suction channel, which can quickly discharge the debris and realize the cleaning of the bottom of the hole, thereby further improving the hole-opening efficiency.

[0049] (10) The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention also has a plurality of stirring blades on the outer wall of the rotary jet drill rod, which can be used for the construction of pre-drilled rotary jet mixing piles, so that the polymer mixture is mixed more evenly, further improving the quality of the piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a flow chart of the ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention;

[0051] Figure 2 It is a structural schematic diagram of the drilling rig in the present invention (multi-axis mechanical arm folded state);

[0052] Figure 3 It is a structural schematic diagram of the drilling rig in the present invention (multi-axis mechanical arm is deployed);

[0053] Figure 4 It is a structural schematic diagram of the drilling rig passing through a low passage in the present invention;

[0054] Figure 5 It is a schematic diagram of the assembly of the drilling rig in the present invention when it is moved to the position to be constructed;

[0055] Figure 6It is a schematic diagram of the drilling rig assembled with the power head and the lifting mast in the present invention in the unfolded state;

[0056] Figure 7 It is a schematic diagram of the combined structure of the power head assembly and the lifting mast assembly in the present invention;

[0057] Figure 8 This is a construction scene of the ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention;

[0058] Fig. 9 Another construction scenario of the ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention;

[0059] Fig.10 It is a schematic diagram of the structure of the hole drilling tool in the present invention;

[0060] Fig.11 It is a schematic diagram of the disassembled structure of the rotary jet drilling tool in the present invention;

[0061] Fig.12 It is a schematic cross-sectional structure diagram of the rotary jet drilling tool in the present invention;

[0062] Fig.13 for Fig.12 Schematic diagram of the local enlarged structure at K in the middle;

[0063] Fig.14 It is a schematic diagram of the three-dimensional structure of the rotary jet splitter in the present invention;

[0064] Fig.15 It is a cross-sectional structural schematic diagram of the rotary jet splitter in the present invention;

[0065] Fig.16 It is a schematic diagram of the split structure of the rotary jet splitter in the present invention;

[0066] Fig.17 It is a schematic diagram of the three-dimensional structure of the lengthened drill rod in the present invention;

[0067] Fig.18 It is a schematic cross-sectional structure diagram of the lengthened drill rod in the present invention;

[0068] Fig.19 It is a schematic diagram of the three-dimensional structure of the rotary jet drilling rod in the present invention;

[0069] Fig. 20 It is a schematic cross-sectional structure diagram of the rotary jet drilling rod in the present invention;

[0070] Fig.21 for Fig. 20 A schematic diagram of the local enlarged structure at M in the middle;

[0071] Fig. 22It is a schematic diagram of the three-dimensional structure of the vacuum back-suction device in the present invention;

[0072] Fig.23 It is a cross-sectional structural schematic diagram of the vacuum back-sucking device of the present invention (the sealing plunger is in a normally closed state);

[0073] Fig.24 It is a cross-sectional structural schematic diagram of the vacuum back-sucking device of the present invention (the sealing plunger is in a pressurized and opened state);

[0074] Fig.25 It is a schematic diagram of the structure of the rotary jet drilling tool with stirring blades in the present invention;

[0075] Fig.26 It is a schematic diagram of the construction scene of the ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention.

[0076] Explanation of the symbols in the schematic diagram:

[0077] 100, drilling rig; 11, crawler chassis; 12, multi-axis mechanical arm; 12-1, large power arm; 12-2, intermediate power arm; 12-3, retractable hydraulic power arm; 13, hydraulic vacuum suction pump; 14, hydraulic oil pump assembly; 15, control console; 16, electrical assembly; 200, power head assembly; 21, drill pipe mounting hole; 300, lifting mast assembly; 400, jet drilling tool; 41, jet diverter; 41-1, diverter housing; 4 1-2, rotary shaft; 41-2-1, diverter joint; 41-2-2, stepped rotary joint; 41-2-3, sealing steel ring; 41a, vacuum suction interface; 41b, first high-pressure polymer interface; 41c, second high-pressure polymer interface; 41d, third high-pressure polymer interface; 41e, compressed air interface; 42, extended drill pipe; 42-1, extended drill pipe upper joint; 42-2, extended drill pipe lower joint; 43, rotary jet drill pipe; 4 3a, vacuum back-suction channel; 43b, first high-pressure polymer channel; 43c, second high-pressure polymer channel; 43d, third high-pressure polymer channel; 43e, high-pressure gas channel; 43-1, upper joint of jet-jet drill pipe; 43-2, dual-channel jet-jet nozzle; 43-2a, high-pressure polymer nozzle; 43-2b, high-pressure gas nozzle; 43-3, confluence block; 43-3-1, confluence ring groove; 43-4, stirring blade; 44, vacuum back-suction device ; 44-1, rod body; 44-1-1, back suction port; 44-1-2, multi-layer back suction holes; 44-1-3, back suction channel; 44-1-4, confluence chamber; 44-2, wireless pressure sensor; 44-3, high-strength spring; 44-4, sealing plunger; 44-5, spiral regulator; 45, drill bit; 41', ordinary drill rod; 42', down-the-hole hammer drill bit; 500, high-pressure grouting pump; 600, air compressor; 700, ground recovery device. DETAILED DESCRIPTION

[0078] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0079] [Example]

[0080] Combination Figure 1 As shown, the ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of this embodiment includes the following construction steps:

[0081] S1. Movement and assembly of rotary jet grouting equipment in a limited micro space:

[0082] The rotary jet grouting equipment includes a drilling rig 100, a power head assembly 200, a sliding mast assembly 300, a hole drilling tool and a rotary jet drilling tool 400. In order to facilitate the movement of the drilling rig 100 in an ultra-low clearance micro space, the power head assembly 200, the sliding mast assembly 300 and the drilling rig 100 are designed to be detachable. The drilling rig 100 is used as a carrier of the rotary jet grouting equipment, and is provided with a foldable multi-axis mechanical arm 12. The sliding mast assembly 300 is detachably mounted on the multi-axis mechanical arm 12, and the power head assembly 200 is mounted on the sliding mast assembly 300. The sliding mast assembly 300 can drive the drilling tool assembly 400 to drill or lift. The power head assembly 200 is used to drive the drilling tool to rotate. After the sliding mast assembly 300 is disassembled, the multi-axis mechanical arm 12 is operated to fold to reduce the overall height of the drilling rig 100, and the drilling rig 100 is controlled to walk through a low passage to enter a position where rotary jet grouting is required; wherein, Figure 2 The multi-axis robot arm 12 is shown in a folded state. Figure 3 The multi-axis robot arm 12 is shown in the expanded state; Figure 4 As shown, when the multi-axis robot arm 12 is in the folded state, the height of the drilling rig 100 is greatly reduced, and it can pass through low passages such as basement doorways, thereby solving the problem that the existing rotary jet grouting equipment is restricted by low passages and cannot be used in ultra-low clearance occasions.

[0083] like Figure 5 As shown, after the drilling rig 100 moves to the designated position, the multi-axis mechanical arm 12 is controlled to extend to the position to be constructed, and the sliding mast assembly 300 is installed at the free end of the multi-axis mechanical arm 12, and the power head assembly 200 is installed on the sliding mast assembly 300, forming Figure 6 In the state shown, since the multi-axis mechanical arm 12 has multiple degrees of freedom, it can flexibly extend into some tortuous spaces for construction. Meanwhile, the high-pressure grouting pump 500, the air compressor 600 and the ground recovery device 700 are in place. Figure 8 and Fig. 9Different arrangement scenarios of the high-pressure grouting pump 500, the air compressor 600 and the ground recovery device 700 are shown, that is, multiple high-pressure grouting pumps 500 can be arranged horizontally or vertically, and can be arranged specifically according to the on-site space.

[0084] S2, opening of the surface hard shell layer:

[0085] Since this construction method is mainly used for the reinforcement of existing buildings, there is often a hard shell layer such as concrete in the space of the existing building, so it is necessary to open holes on the surface before the rotary jet grouting construction. The specific construction process is:

[0086] A rotary jet flow divider 41 is installed on the power head assembly 200, a hole drilling tool is installed on the rotary jet flow divider 41, and an air compressor pipeline and a vacuum return suction pipeline are connected; Fig.10 As shown, in this embodiment, the above-mentioned hole-opening drilling tool includes a common drill rod 41' and a down-the-hole hammer drill bit 42'. The upper end of the common drill rod 41' is connected to the rotary jet diverter 41, and the down-the-hole hammer drill bit 42' is fixed to the lower end of the common drill rod 41'. The centers of the common drill rod 41' and the down-the-hole hammer drill bit 42' are both provided with a debris suction channel. The down-the-hole hammer drill bit has the advantages of high hole-opening efficiency, long service life, and low construction cost.

[0087] During construction, the power head assembly 200 is used to drive the drilling tool to perform drilling operations on the surface hard shell layer. The drilling tool rotates while drilling, and at the same time, the air compressor pipeline is used to give the drilling tool impact power, and the debris at the bottom of the hole is sucked to the ground recovery device 700 through the vacuum back-suction pipeline, which can quickly discharge the debris and achieve the cleaning of the bottom of the hole, further improving the drilling efficiency; after the drilling operation, the drilling tool is lifted by the sliding mast assembly 300 and the drilling tool is disassembled. The above-mentioned rotary jet diverter 41 can use the same diverter as the rotary jet grouting construction process, or an existing diverter can be used. In this embodiment, it is preferred to use the same diverter to facilitate on-site operation; if different diverters are used, the diverters need to be disassembled together after the drilling is completed.

[0088] S3, rotary jet grouting construction:

[0089] A jet grouting drill 400 is installed on the jet grouting diverter 41. Fig.11 and Fig.12As shown, the jet grouting drill 400 includes a jet grouting drill rod 43, a vacuum suction device 44 and a drill bit 45 which are arranged in sequence. The upper end of the jet grouting drill rod 43 is fixed on the jet grouting diverter 41, the vacuum suction device 44 is fixed on the lower end of the jet grouting drill rod 43, and the drill bit 45 is fixed on the lower end of the vacuum suction device 44. The above-mentioned drill bit can adopt a multi-wing alloy drill bit; at the same time, the high-pressure polymer interface of the jet grouting diverter 41 is connected to the corresponding high-pressure grouting pump 500, and the compressed air interface 41e of the jet grouting diverter 41 is connected to the air compressor 600; then a test injection is carried out to check the safety of each pipeline and the injection pressure;

[0090] After the test jetting is completed, normal drilling is carried out, and an extended drill rod 42 is added to reach the designed pile bottom elevation position;

[0091] The backstage feeds materials according to the design ratio, starts the high-pressure grouting pump 500 and the air compressor 600 in sequence, and delivers the polymer and compressed air to the multi-level dual-channel rotary jet nozzle 43-2 at the bottom of the rotary jet drill rod 43 under high pressure, and performs multi-level high-pressure jetting and stirring of the soil to form piles; at the same time, the rotary jet drill 400 is gradually lifted according to the designed lifting speed; after completing a stroke, a section of the extended drill rod 42 is disassembled, and multi-level high-pressure rotary jetting is continued until the designed pile top elevation is reached; after reaching the designed pile top elevation, the last 1m can be repeatedly jetted and stirred;

[0092] During the rotary jet grouting process, the wireless pressure sensor 44-2 in the vacuum suction device 44 monitors the bottom hole pressure in real time. When the bottom hole pressure exceeds the design pressure, the vacuum suction pipeline is opened for suction. At the same time, the sealing plunger 44-4 in the vacuum suction device 44 adaptively opens the multi-layer suction holes 44-1-2 under the action of the bottom hole pressure, and sucks the high-pressure polymer mixture at the bottom of the hole to the ground recovery device 700.

[0093] The above-mentioned polymer refers to cement paste, curing agent, and various high molecular polymers, and the polymer mixed liquid refers to a mixture formed by mixing cement paste, curing agent, and various high molecular polymers with soil and air.

[0094] The above-mentioned ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method is adopted. The power head and the sliding mast are made detachable through the optimized design of the rotary jet grouting equipment, and the foldable multi-axis mechanical arm design is used. After the multi-axis mechanical arm is folded, it can be flexibly moved in a limited micro space, so as to achieve the purpose of flexible hole opening and rotary jet grouting in a narrow and tortuous space. During the construction process, a hole is first opened in the surface hard shell layer and then rotary jet grouting is carried out. During the rotary jet grouting process, a multi-level double-channel rotary jet nozzle is used to realize high-pressure spraying at multiple levels, so that the construction efficiency is doubled and the pile quality is better. At the same time, the vacuum back-suction device with innovative design can adaptively adjust the opening amplitude of the back-suction hole, and use a wireless pressure sensor to monitor the bottom hole pressure in real time. When the bottom hole pressure exceeds the design pressure, the vacuum back-suction pipeline is opened for suction. No manual intervention is required in the entire rotary jet process, which avoids quality problems caused by manual operation errors, makes the construction operation simpler and more convenient, and greatly reduces the construction cost.

[0095] Reference Figure 2 , Figure 3 and Figure 6 As shown, in this embodiment, the multi-axis mechanical arm 12 includes a large power arm 12-1, an intermediate power arm 12-2 and a telescopic hydraulic power arm 12-3. The lower end of the large power arm 12-1 is movably mounted on a turntable, and the turntable is mounted on the crawler chassis 11 of the drilling rig 100, so that the multi-axis mechanical arm 12 can rotate as a whole; one end of the intermediate power arm 12-2 is movably mounted on the upper end of the large power arm 12-1, and the other end of the intermediate power arm 12-2 is movably connected to the telescopic hydraulic power arm 12-3 to form a six-axis rotatable telescopic power arm. Each connection joint between the large power arm 12-1, the intermediate power arm 12-2 and the telescopic hydraulic power arm 12-3 can be independently rotated and controlled, and the length of the telescopic hydraulic power arm 12-3 can be extended and retracted. The multi-axis mechanical arm 12 has a compact structure after folding and occupies a small space, so that the drilling rig can pass smoothly in a low passage. The multi-axis mechanical arm 12 has a high degree of freedom and can adapt to complex and tiny spaces, ensuring that the power head and drilling tools can be extended into a limited micro space for rotary jet grouting construction. It has the advantages of flexible movement, diverse application scenarios, and convenient construction in a limited space. As a specific embodiment, the rotation axis at both ends of the large power arm 12-1 is preferably set horizontally, and the intermediate power arm 12-2 can rotate along its axis as a whole, so that the large power arm 12-1, the intermediate power arm 12-2 and the telescopic hydraulic power arm 12-3 can be compactly folded together and can be flexibly controlled in three-dimensional space. The rotation control of the large power arm 12-1, the intermediate power arm 12-2 and the telescopic hydraulic power arm 12-3 and the telescopic control of the telescopic hydraulic power arm 12-3 can all be hydraulically controlled.

[0096] like Figure 6As shown, in this embodiment, a hydraulic oil pump assembly 14, a control console 15 and an electrical assembly 16 are also installed on the crawler chassis 11 of the drilling rig 100, and the vacuum back-suction pipeline also includes a hydraulic vacuum back-suction pump 13 installed on the crawler chassis 11. The hydraulic vacuum back-suction pump 13, the hydraulic oil pump assembly 14, the control console 15 and the electrical assembly 16 are distributed around the crawler chassis 11 to form a space for the multi-axis mechanical arm 12 to fold in the middle of the crawler chassis 11. The multi-axis mechanical arm 12 is folded on the crawler chassis 11 so that the drilling rig 100 can pass through a low passage. With this drilling rig structural layout, the overall height of the drilling rig is effectively reduced after the multi-axis mechanical arm 12 is folded, and the multi-axis mechanical arm 12, the hydraulic vacuum back-suction pump 13, the hydraulic oil pump assembly 14, the control console 15 and the electrical assembly 16 are integrated and installed on the crawler chassis 11, with a simple and compact structure and convenient operation, ensuring that the drilling rig can be flexibly moved and rotated in ultra-low clearance scenarios. Preferably, the hydraulic oil pump assembly 14 is arranged at the rear of the crawler chassis 11, and the multi-axis mechanical arm 12 is installed at the front of the crawler chassis 11, which is conducive to the balance of the center of gravity of the entire drilling rig. In this embodiment, the crawler chassis 11 can adapt to different construction environments and is flexible in turning. The suction port of the hydraulic vacuum suction pump 13 is connected to the vacuum suction interface 41a of the rotary jet diverter 41, which can suck out the polymer mixture in the ground and transport it to the ground recovery device. The hydraulic oil pump assembly 14 is the hydraulic power source of the drilling rig, which can provide power for the walking of the crawler chassis 11, the movement of the multi-axis mechanical arm 12, and the operation of the hydraulic vacuum suction pump 13. The console 15 may have a display screen, a plurality of joysticks and switches for controlling the various execution parts of the rotary jet grouting operation. The electrical assembly 16 integrates electrical components and control circuits for realizing electrical control of the entire rotary jet grouting system. In addition, if Figure 7 As shown, the power head assembly 200 is mounted on the lifting mast assembly 300, and a drill rod mounting hole 21 for mounting a drilling tool is provided on the power head assembly 200, and the lifting mast assembly 300 can drive the power head assembly 200 to move up and down. The above-mentioned power head assembly 200 and the lifting mast assembly 300 can adopt existing structures, which will not be described in detail here.

[0097] The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of this embodiment adopts a multi-level rotary jet grouting design to improve the construction efficiency. For this purpose, it is necessary to use a rotary jet diverter 41 and a rotary jet drill rod 43 with an optimized design. The rotary jet diverter 41 is used to distribute the rotary jet cutting gas and liquid medium into the drill tool, and ensure that the drill tool can rotate 360° continuously, overcoming the problem that the MJS equipment can only swing and spray, resulting in low construction efficiency. Figures 14 to 16As shown, in this embodiment, the above-mentioned jet splitter 41 includes a splitter housing 41-1 and a rotating shaft body 41-2 that can rotate freely in the splitter housing 41-1. The rotating shaft body 41-2 can be installed on the power head assembly 200, and the power head assembly 200 drives the rotating shaft body 41-2 to rotate. During this process, the splitter housing 41-1 can basically not rotate. The jet drill rod 43 is used to spray outward through the nozzle to form a jet to cut and stir the soil, such as Fig.13 and Fig.19 and Fig. 20 As shown, the rotary jet drill rod 43 has a vacuum back-suction channel 43a, a high-pressure polymer channel and a high-pressure gas channel 43e. The vacuum back-suction channel 43a is connected to the vacuum back-suction interface 41a on the diverter housing 41-1, and the vacuum back-suction interface 41a is connected to the vacuum back-suction pipeline; the high-pressure polymer channel is connected to the high-pressure polymer interface on the diverter housing 41-1; the high-pressure gas channel 43e is connected to the compressed air interface 1e on the diverter housing 41-1; at least two groups of dual-channel rotary jet nozzles 43-2 are axially spaced at the lower part of the rotary jet drill rod 43, and each group of dual-channel rotary jet nozzles 43-2 is axially spaced at least two groups. 3-2 both include a high-pressure polymer nozzle 43-2a and a high-pressure gas nozzle 43-2b located on the periphery of the high-pressure polymer nozzle 43-2a, the high-pressure polymer nozzle 43-2a is connected to the corresponding high-pressure polymer channel, and the high-pressure gas nozzle 43-2b is connected to the corresponding high-pressure gas channel 43e; during the rotary jet grouting process, the polymer liquid can be transported to the nozzle of the rotary jet drill rod 43 through the high-pressure polymer interface and the high-pressure polymer channel respectively, and at the same time, the gas is transported to the nozzle of the rotary jet drill rod 43 through the compressed air interface 41e and the high-pressure gas channel 43e to form a high-pressure cutting jet. In addition, the polymer inputted from the high-pressure polymer interface is transported to the high-pressure polymer nozzle 43-2a through the high-pressure polymer channel and ejected outwardly, and the high-pressure air inputted from the compressed air interface 41e is transported to the high-pressure gas nozzle 43-2b through the high-pressure gas channel 43e and ejected outwardly. In this process, the high-pressure polymer is ejected from the central high-pressure polymer nozzle 43-2a, and the high-pressure gas surrounds the high-pressure polymer jet and ejects from the high-pressure gas nozzle 43-2b together. The high-pressure gas can protect the high-pressure strength of the high-pressure polymer jet, thereby ensuring that the high-pressure jet cuts the soil more effectively and mixes more evenly. Since the high-pressure jet can be used for cutting and stirring the soil at multiple levels, the construction speed can be doubled for each additional level, thereby achieving an effect of doubling the construction efficiency and better pile quality, solving the problem of low construction efficiency of existing rotary jet grouting equipment.

[0098] In this embodiment, the vacuum back-suction channel 43a is located at the center of the rotary jet drill rod 43, the high-pressure gas channel 43e is located at the outermost side of the rotary jet drill rod 43, and the high-pressure polymer channel is located between the vacuum back-suction channel 43a and the high-pressure gas channel 43e. The vacuum back-suction channel 43a is a central circular hole, and the high-pressure polymer channel and the high-pressure gas channel 43e are a number of through holes evenly distributed circumferentially. In this way, the size of the vacuum back-suction channel 43a can be designed to be larger, and the back-suction flow rate can be larger and smoother; at the same time, it can facilitate the setting of multiple dual-channel rotary jet nozzles 43-2, facilitate the connection between the high-pressure gas channel 43e and the high-pressure polymer channel and the dual-channel rotary jet nozzle 43-2, and facilitate the production of the rotary jet drill rod. Fig.21 As shown, the lower end of the jet grouting drill rod 43 has a confluence block 43-3 for blocking the corresponding high-pressure polymer channel and high-pressure gas channel 43e, and the confluence ring groove 43-3-1 connected to the corresponding channel is provided on the confluence block 43-3, and the high-pressure polymer nozzle 43-2a is respectively connected to the confluence ring groove 43-3-1 corresponding to the corresponding high-pressure polymer channel, and the high-pressure gas nozzle 43-2b is respectively connected to the high-pressure gas channel 43e or the confluence ring groove 43-3-1 corresponding to the high-pressure gas channel 43e. With this design, the confluence of each channel in the jet grouting drill rod 43 can be achieved, the injection pressure of the dual-channel jet grouting nozzle 43-2 can be ensured, and the efficient cutting and mixing of the soil can be achieved; at the same time, the confluence block 43-3 is used for assembly and blocking, the structure is simple, and the difficulty of making the internal channel of the jet grouting drill rod 43 is reduced.

[0099] For the internal structure of the jet grouting drill rod 43, combined with Figures 19 to 21Taking the arrangement of three groups of dual-channel jet nozzles 43-2 as an example, the three groups of dual-channel jet nozzles 43-2 are arranged on the outer side wall of the jet drill rod 43 along the axial direction of the drill tool. Correspondingly, the high-pressure polymer channels are also provided with three independent groups, namely, the first high-pressure polymer channel 43b, the second high-pressure polymer channel 43c and the third high-pressure polymer channel 43d. The first high-pressure polymer channel 43b, the second high-pressure polymer channel 43c and the third high-pressure polymer channel 43d are arranged from the inside to the outside. Similarly, the high-pressure polymer interfaces on the jet diverter 41 are also provided with three groups, namely, the first high-pressure polymer interface 41b, the second high-pressure polymer interface 41c and the third high-pressure polymer interface 41d. The first high-pressure polymer interface The port 41b is connected to the high-pressure polymer nozzle 43-2a in the lowermost dual-channel rotary spray nozzle 43-2 through the corresponding first high-pressure polymer channel 43b, the second high-pressure polymer interface 41c is connected to the high-pressure polymer nozzle 43-2a in the middle dual-channel rotary spray nozzle 43-2 through the corresponding second high-pressure polymer channel 43c, and the third high-pressure polymer interface 41d is connected to the high-pressure polymer nozzle 43-2a in the uppermost dual-channel rotary spray nozzle 43-2 through the corresponding third high-pressure polymer channel 43d. In this way, the three groups of dual-channel rotary spray nozzles 43-2 can independently configure high-pressure polymer jets, and can perform high-pressure jet cutting and mixing of soil at multiple levels. The construction speed is three times that of the prior art, and the quality of piles is better. In addition, the upper end of the jet grouting drill rod 43 is directly or indirectly connected to the rotary shaft 41-2 of the jet grouting diverter 41 through the extended drill rod 42. According to the designed pile foundation depth, the jet grouting drill rod 43 can be directly installed on the jet grouting diverter 41 for use, or the length of the jet grouting drill rod 43 penetrating into the ground can be increased by extending the drill rod 42. The number of extended drill rods 42 can also be determined according to needs. The channel in the extended drill rod 42 corresponds to the channel on the jet grouting drill rod 43.

[0100] The vacuum back-sucking device 44 acts like an adaptively opened valve, which can automatically open when the pressure in the hole is greater than the set pressure to achieve the back-sucking of the polymer mixture in the hole, reduce the pressure in the hole, and thus reduce the squeezing and disturbance of the surrounding soil. Figure 22 to Figure 24As shown, the vacuum back-suction device 44 has a multi-layer back-suction hole 44-1-2 connected to the vacuum back-suction channel 43a of the rotary jet drill rod 43, and the vacuum back-suction device 44 is provided with a wireless pressure sensor 44-2, a high-strength spring 44-3 and a sealing plunger 44-4 from top to bottom. The sealing plunger 44-4 has a back-suction port 44-1-1 below, and the sealing plunger 44-4 is sealed with the multi-layer back-suction hole 44-1-2. The sealing plunger 44-4 can move up and down according to the change in the pressure of the polymer mixture in the ground to control the opening and closing and opening amplitude of the multi-layer back-suction hole 4-1-2. The vacuum back-suction device 44 has an adaptive micro-disturbance effect. When the pressure of the polymer mixture in the ground increases, the pressure acts upward on the sealing plunger 44-4. When the pressure in the ground on the sealing plunger 44-4 is greater than the elastic force of the high-strength spring 44-3, the sealing plunger 44-4 automatically moves upward to open the multi-layer back-suction hole 44-1-2. The greater the pressure in the ground, the greater the opening amplitude of the multi-layer back-suction hole 44-1-2. The polymer mixture at the bottom of the hole is transported to the ground recovery device along the multi-layer back-suction hole under the suction of the vacuum pump, which automatically achieves the effect of increasing the pressure return channel. No manual intervention is required during the entire rotary grouting process, avoiding quality problems caused by manual operation errors, making the construction operation simpler and more convenient, and solving the problem that the existing rotary grouting equipment needs to rely on the operator to manually adjust the back-suction flow according to the sensed underground stress, which is complicated to operate and easy to affect the construction quality due to operation errors. The wireless pressure sensor 44-2 is connected to the ground mechanical equipment operating platform for communication and is used to control the start or close of the vacuum back-suction pipeline. The wireless pressure sensor 44-2 can transmit the hole pressure to the ground mechanical equipment operating platform, such as the above-mentioned control console 15, in real time. The ground mechanical equipment operating platform (control console 15) can adjust the pumping pressure of the high-pressure pump and the start and stop of the hydraulic vacuum back-suction pump 13 according to the hole pressure, thereby dynamically adjusting the hole pressure. Specifically, the vacuum back-suction device 44 includes a rod body 44-1 fixedly installed at the lower end of the rotary jet drill rod 43, and an installation cavity is provided in the rod body 44-1. A wireless pressure sensor 44-2, a high-strength spring 44-3 and a sealing plunger 44-4 are installed in the installation cavity from top to bottom. A multi-layer back-suction hole 44-1-2 cooperating with the sealing plunger 44-4 is provided on the side wall of the installation cavity. The multi-layer back-suction hole 44-1-2 is connected to the vacuum back-suction channel 43a of the rotary jet drill rod 43 through the back-suction channel 44-1-3 on the rod body 44-1. The lower end of the rod body 44-1 has a back-suction port 44-1-1 opposite to the sealing plunger 44-4. The sealing plunger 44-4 can move according to the change in the pressure of the polymer mixture in the ground to control the opening and closing and the opening and closing amplitude of the multi-layer back-suction hole 4-1-2.For the convenience of manufacturing, the installation cavity and the back-suction channel 44-1-3 can be arranged on the central insert, and the central insert is integrally installed inside the mounting rod body 44-1. The back-suction channel 44-1-3 is distributed on the periphery of the installation cavity. The multi-layer back-suction holes 44-1-2 are arranged at the lower part of the installation cavity, and multiple layers can be evenly distributed circumferentially. The sealing plunger 44-4 can slide up and down in the installation cavity and maintain the closed state of the multi-layer back-suction holes 44-1-2 under the action of the high-strength spring 44-3 (such as. Fig.23 As shown in the figure, at this time, since the multi-layer back-suction holes 44-1-2 are closed, the underground mixed liquid will not be back-sucked; when the pressure of the underground mixed liquid increases and the pressure of the mixed liquid on the sealing plunger 44-4 is greater than the elastic force of the high-strength spring 44-3, the sealing plunger 44-4 is forced to move upward, and at this time, part of the multi-layer back-suction holes 44-1-2 are opened, and then the vacuum pump is used to suck the polymer mixed liquid at the bottom of the hole to the ground recovery device (as shown in the figure). Fig.24 As shown in the figure, the bottom hole pressure is reduced; the greater the pressure of the mixed liquid at the bottom of the hole, the greater the opening of the multi-layer back-suction holes 44-1-2, and the greater the amount of mixed liquid back-suction. When the pressure of the mixed liquid at the bottom of the hole decreases with the back-suction, the sealing plunger 44-4 moves downward to reduce the opening amount of the multi-layer back-suction holes 44-1-2 or close the multi-layer back-suction holes 44-1-2, thereby realizing adaptive regulation of the bottom hole pressure. The high-strength spring 44-3 mentioned above adopts a high-strength high-manganese alloy compression spring, and the pressure of the high-strength spring 44-3 changes with the movement of the sealing plunger 44-4. One end of the high-strength spring 44-3 acts on the wireless pressure sensor 44-2, and the other end acts on the sealing plunger 44-4. A confluence chamber 44-1-4 is provided at the top of the rod body 44-1, and a plurality of back-suction channels 44-1-3 are connected to the confluence chamber 44-1-4. After the rod body 44-1 is installed to the lower end of the jet-jet drill rod 43, the confluence chamber 44-1-4 is connected to the vacuum back-suction channel 43a. In addition, a back-suction port 44-1-1 is provided at the lower end of the rod body 44-1 of the vacuum back-suction device 44. A spiral adjuster 44-5 is connected to the inner thread of the back-suction port 44-1-1. The spiral adjuster 44-5 has a central through hole. The upper end of the spiral adjuster 44-5 abuts against the lower end surface of the sealing plunger 44-4. The spiral adjuster 44-5 also has a screwing structure for facilitating the adjustment operation. The screw adjuster 44-5 can be rotated by the screwing structure, so that the screw adjuster 44-5 moves up and down relative to the rod body 44-1, and then the initial position of the sealing plunger 44-4 and the initial compression state of the high-strength spring 44-3 can be adjusted, and the minimum hole pressure can be adjusted, which is convenient for accurate control of the hole construction pressure and ensures the quality of pile formation. The above-mentioned screwing structure can adopt at least two columns arranged on the lower end surface of the screw adjuster 44-5, and the columns are connected and rotated by special tools to achieve the position adjustment of the screw adjuster 44-5, or the central through hole of the screw adjuster 44-5 can be designed as an inner hexagonal shape, and adjusted by an inner hexagonal wrench.

[0101] Further references Figures 14 to 16 As shown, in this embodiment, the upper end of the rotary shaft body 41-2 has a stepped rotary joint 41-2-2, and a plurality of channels are correspondingly arranged on the stepped surface of the stepped rotary joint 41-2-2, and the channels can be circular through holes evenly distributed on the corresponding stepped surfaces; the diverter housing 41-1 has a stepped cavity adapted to the stepped rotary joint 41-2-2, and a diverter groove corresponding to the corresponding channel is arranged on the step surface of the stepped cavity, and the vacuum back suction interface 41a, the high-pressure polymer interface and the compressed air interface 41e are respectively connected to the corresponding diverter groove; the drilling tool has a stepped cavity adapted to the stepped rotary joint 41-2-2, and a diverter groove corresponding to the corresponding channel is arranged on the stepped surface of the stepped cavity. The suction channel is connected to the vacuum suction interface 41a through the diverter groove, and can be connected to the hydraulic vacuum suction pump 13 through the vacuum suction interface 41a. The high-pressure polymer interface can be connected to the high-pressure grouting pump 500. The high-pressure grouting pump 500 inputs the polymer from the corresponding high-pressure polymer interface into the drill tool, and distributes it to each polymer channel through the corresponding diverter groove. The compressed air interface 41e can be connected to the ground air compressor 600. The air compressor 600 inputs the compressed air from the compressed air interface 41e into the drill tool, and distributes it to each high-pressure air channel through the corresponding diverter groove. The above-mentioned stepped rotary joint structure can not only realize the uniform diversion of each channel, but also facilitate the sealing assembly between each channel, making the production of the rotary jet diverter more convenient, and the number of channels can be increased or decreased according to the design needs, realizing the multi-channel high-pressure rotary jet diversion effect of the drill tool. In addition, the step side walls of the stepped swivel joint 41-2-2 are respectively provided with sealing steel rings 41-2-3 that are sealed with the inner side walls of the stepped concave cavity. The sealing steel rings 41-2-3 can be made of high-elasticity steel rings, which can ensure effective isolation and rotational sealing between the internal channels of the rotary jet splitter 41, and at the same time ensure the stable rotational movement of the splitter housing 41-1 and the rotary shaft body 41-2. Since the splitter housing 41-1 with the vacuum back-suction interface 41a, the high-pressure polymer interface and the compressed air interface 41e does not rotate with the rotary shaft body 41-2, the rotary jet splitter 41 can be rotated continuously to meet the construction requirements of continuously rotating mixing piles and high-pressure rotary jet piles.

[0102] In order to facilitate the connection of drilling tools, in the present embodiment, the lower end of the rotating shaft body 41-2 has a diverter joint 41-2-1 for connecting the extended drill rod 42 or the rotary jet drill rod 43, and the two ends of the extended drill rod 42 are respectively provided with an extended drill rod upper joint 42-1 and an extended drill rod lower joint 42-2, and the upper end of the rotary jet drill rod 43 is provided with a rotary jet drill rod upper joint 43-1. The diverter joint 41-2-1 is complementary in shape to the extended drill rod upper joint 42-1 and the rotary jet drill rod upper joint 43-1, and the extended drill rod lower joint 42-2 is complementary in shape to the rotary jet drill rod upper joint 43-1, and the diverter joint 41-2-1, the extended drill rod upper joint 42-1, the extended drill rod lower joint 42-2 and the rotary jet drill rod upper joint 43-1 all adopt a stepped butt joint structure. For example, when the diverter joint 41-2-1 adopts a stepped convex joint, the extended drill pipe upper joint 42-1 adopts a stepped concave joint with complementary shapes, the extended drill pipe lower joint 42-2 adopts a stepped convex joint, and the rotary jet drill pipe upper joint 43-1 adopts a stepped concave joint with complementary shapes. The above design can facilitate the assembly of the rotary jet diverter 41, the extended drill pipe 42 and the rotary jet drill pipe 43, and the stepped butt joint structure design can facilitate the connection and sealing of each channel, ensure the independence of each channel in the rotary jet drill, effectively avoid the blockage of the channel and the nozzle, and ensure the stability and reliability of the rotary jet drill during the construction process; at the same time, the stepped butt joint design has high connection strength and good drill coaxiality, which can further improve the construction stability of the drill. In addition, the rotary jet diverter 41, the extended drill pipe 42 and the rotary jet drill pipe 43 can be fixed by the threaded connection of the stepped joint, or the stepped butt joint can be connected with the flange after docking.

[0103] In order to facilitate the production of jet grouting drill tools, the rotating shaft 41-2, the extended drill rod 42 and the jet grouting drill rod 43 are all assembled by sleeve connection of steel pipes, and the corresponding holes on the rotating shaft 41-2, the extended drill rod 42 and the jet grouting drill rod 43 are all arranged on the wall of the corresponding steel pipe. With the above-mentioned steel pipe sleeve assembly structure, the production of the rotating shaft 41-2, the extended drill rod 42 and the jet grouting drill rod 43 is simpler and more convenient, which reduces the production cost of the drilling tools; and the drill rod structure has high strength and can cope with the construction of micro-disturbance jet grouting piles in soils with different physical properties. For details, please refer to Fig.15 and Fig.16As shown, the rotating shaft body 41-2 is made of 5 layers of steel pipes, the central hole of the first circle of steel pipes from the inside to the outside is the suction channel connected to the vacuum suction interface 41a, and the multiple through holes distributed around the pipe wall are the first high-pressure polymer channels connected to the first high-pressure polymer interface 41b, and the upper ends of the first high-pressure polymer channels are connected through the corresponding diverter grooves in the diverter shell 41-1; the second circle of steel pipes is sleeved on the outside of the first circle of steel pipes, and the height of the second circle of steel pipes is less than the height of the first circle of steel pipes to form a stepped structure at both ends, and the multiple through holes distributed around the pipe wall of the second circle of steel pipes are the second high-pressure polymer channels connected to the second high-pressure polymer interface 41c, and the upper ends of the second high-pressure polymer channels are connected through the corresponding diverter grooves in the diverter shell 41-1; the third circle The steel pipe is sleeved on the outside of the second circle of steel pipe, and the height of the third circle of steel pipe is less than that of the second circle of steel pipe, so as to form a stepped structure at both ends. The several through holes distributed around the wall of the third circle of steel pipe are the third high-pressure polymer channels connected to the third high-pressure polymer interface 41d, and the upper ends of each third high-pressure polymer channel are connected through the corresponding diverter groove in the diverter shell 41-1; the fourth circle of steel pipe is sleeved on the outside of the third circle of steel pipe, and the height of the fourth circle of steel pipe is less than that of the third circle of steel pipe, so as to form a stepped structure at both ends. The several through holes distributed around the wall of the fourth circle of steel pipe are the high-pressure air channels connected to the compressed air interface 41e, and the upper ends of each high-pressure air channels are connected through the corresponding diverter groove in the diverter shell 41-1; the fifth circle of steel pipe is sleeved on the outside of the fourth circle of steel pipe. The structure of the extended drill pipe 42 and the rotary jet drill pipe 43 is similar to that of the above-mentioned rotating shaft body 41-2. The main difference is that the height and combination position of each circle of steel pipe are different. For example, Fig.17 and Fig.18 As shown, the heights of the steel pipes of the extended drill rod 42 are substantially the same, and the steel pipes are staggered and spliced ​​from the inside to the outside to form a stepped joint structure; Fig. 20 As shown, the heights of the various circles of steel pipe of the jet grouting drill rod 43 are different. When combined to form a stepped joint structure at the upper portion of the jet grouting drill rod 43, an assembly space for installing a manifold block 43-3 is reserved at the lower end according to the position of each dual-channel jet grouting nozzle 43-2, and the manifold block 43-3 is used to achieve the blocking and gathering and connecting functions of the corresponding channels.

[0104] like Fig.25 As shown, as another embodiment, a plurality of stirring blades 43-4 are further provided on the outer wall of the jet grouting drill rod 43. The stirring blades 43-4 can stir the polymer mixture during construction, so that the polymer mixture is mixed more evenly, further improving the quality of the pile, and can be used for the construction of pre-drilled jet grouting piles.

[0105] Fig.26A construction scene of the ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of this embodiment is shown. Due to the space limitations of existing buildings, existing rotary jet grouting equipment is difficult to enter a small space for construction. The present invention cleverly solves the problem of limited space through a special drilling rig design and a multi-axis mechanical arm 12. At the same time, it cooperates with the design of a sliding mast and a power head to enable the drill to enter a small space for rotary jet grouting construction. And through the innovative improvement of the drilling tool, the adaptive micro-disturbance vacuum back-suction device is used to solve the squeezing and disturbance problems of the surrounding soil layers caused by rotary jet grouting, and the reinforcement of existing buildings is achieved. In addition, by cooperating with a multi-channel high-pressure rotary jet diverter and multiple high-pressure rotary nozzles, multi-level point high-pressure injection can be achieved, which greatly improves the efficiency of rotary jet grouting construction.

[0106] Compared with the prior art, the ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method of the present invention has the following beneficial effects:

[0107] 1. The multi-axis rotatable three-section mechanical arm can transport the power head and drilling tools to narrow and tortuous spaces for rotary grouting. In addition, the power head and the lifting mast are detachable, and the three-section mechanical arm can be folded and laid flat, so that it can pass through low passages smoothly, thus achieving the purpose of flexible hole opening and rotary grouting in narrow and tortuous spaces.

[0108] Second, the multi-channel, multi-layer, and multi-level high-pressure rotary grouting construction method is adopted, which changes the original single-point high-pressure rotary grouting construction method into a multi-level double high-pressure rotary grouting method, which greatly improves the construction efficiency and improves the pile quality;

[0109] 3. Using the micro-disturbance vacuum back-absorption method, the high-pressure mixed polymer transmits the pressure to the sealing plunger at the front end of the vacuum back-absorption device in the underground space, thereby compressing the high-strength spring at the rear end, so that the front sealing plunger moves backward as the pressure increases, thereby opening the annular multi-level back-absorption channel switch, and the polymer mixture at the bottom of the hole is transported to the ground recovery device along the multi-layer back-absorption channel under the suction of the vacuum pump; because the device used in the entire micro-disturbance vacuum back-absorption automatically achieves the effect of increasing the pressure reflux channel, there is no need for manual intervention in the entire rotary spraying process, and automation is achieved to avoid quality problems caused by manual operation errors. At the same time, the wireless pressure sensor at the bottom can transmit the pressure in the underground hole to the mechanical equipment operating platform in real time, and can dynamically adjust the pressure in the hole. Since the vacuum back-absorption device is fully domestically produced and does not rely on imports, the construction cost of micro-disturbance rotary spraying grouting is greatly reduced, and it can be widely used.

[0110] The present invention and its embodiments are described schematically above, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and creatively designs a structure and an embodiment similar to the technical solution without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. Ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method, characterized in that: The construction steps include: S1. Movement and assembly of rotary jet grouting equipment in a limited micro space: The rotary jet grouting equipment comprises a drilling rig (100), a power head assembly (200), a lifting mast assembly (300), a hole-opening drill and a rotary jet grouting drill (400); the drilling rig (100) is provided with a foldable multi-axis mechanical arm (12); the multi-axis mechanical arm (12) is operated to fold so as to lower the overall height of the drilling rig (100), and the drilling rig (100) is controlled to move through a low passage and enter a position where rotary jet grouting is required; After the drilling rig (100) moves to the designated position, the multi-axis mechanical arm (12) is controlled to extend to the position to be constructed, and the sliding mast assembly (300) is installed at the free end of the multi-axis mechanical arm (12), and the power head assembly (200) is installed on the sliding mast assembly (300); at the same time, the high-pressure grouting pump (500), the air compressor (600) and the ground recovery device (700) are put into place; S2, opening of the surface hard shell layer: A rotary jet flow divider (41) is installed on the power head assembly (200), a hole drilling tool is installed on the rotary jet flow divider (41), and an air compressor pipeline and a vacuum return suction pipeline are connected; The power head assembly (200) is used to drive the drilling tool to perform drilling operations on the surface hard shell layer. The drilling tool rotates while drilling, and at the same time, an air compressor pipeline is used to give the drilling tool impact power, and the debris at the bottom of the hole is sucked to a ground recovery device (700) through a vacuum suction pipeline. After the drilling operation, the drilling tool is lifted by the lifting mast assembly (300) and the drilling tool is disassembled; S3, rotary jet grouting construction: A jet grouting drill (400) is installed on the jet grouting diverter (41), wherein the jet grouting drill (400) comprises a jet grouting drill rod (43), a vacuum suction device (44) and a drill bit (45) which are arranged in sequence; a high-pressure polymer interface of the jet grouting diverter (41) is connected to a corresponding high-pressure grouting pump (500); and a compressed air interface (41e) of the jet grouting diverter (41) is connected to an air compressor (600); and then a test jet is performed to check the safety of each pipeline and the size of the jet pressure; After the test jetting is completed, normal drilling is carried out, and an extended drill rod (42) is added to reach the designed pile bottom elevation position; The backstage loads materials according to the ratio specified in the design, and starts the high-pressure grouting pump (500) and the air compressor (600) in sequence, and delivers the polymer and compressed air to the multi-level double-channel rotary grouting nozzle (43-2) at the bottom of the rotary grouting drill rod (43) under high pressure, and performs multi-level high-pressure grouting and stirring of the soil to form a pile; at the same time, the rotary grouting drill (400) is gradually lifted according to the designed lifting speed; after completing one stroke, a section of the extended drill rod (42) is removed, and the multi-level high-pressure rotary grouting is continued until the designed pile top elevation is reached; During the rotary jet grouting process, the wireless pressure sensor (44-2) in the vacuum suction device (44) monitors the bottom hole pressure in real time. When the bottom hole pressure exceeds the design pressure, the vacuum suction pipeline is opened for suction. At the same time, the sealing plunger (44-4) in the vacuum suction device (44) adaptively opens the multi-layer suction holes (44-1-2) under the action of the bottom hole pressure, and sucks the high-pressure polymer mixture at the bottom of the hole to the ground recovery device (700).

2. The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method according to claim 1 is characterized in that: The multi-axis mechanical arm (12) comprises a large power arm (12-1), an intermediate power arm (12-2) and a telescopic hydraulic power arm (12-3); the lower end of the large power arm (12-1) is movably mounted on a rotary table, and the rotary table is mounted on a crawler chassis (11) of the drilling rig (100), so that the multi-axis mechanical arm (12) can rotate as a whole; one end of the intermediate power arm (12-2) is movably mounted on the upper end of the large power arm (12-1), and the other end of the intermediate power arm (12-2) is movably connected to the telescopic hydraulic power arm (12-3), forming a six-axis rotatable telescopic power arm.

3. The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method according to claim 2 is characterized in that: A hydraulic oil pump assembly (14), a control console (15) and an electrical assembly (16) are also installed on the crawler chassis (11) of the drilling rig (100); the vacuum return suction pipeline also includes a hydraulic vacuum return suction pump (13) installed on the crawler chassis (11); the hydraulic vacuum return suction pump (13), the hydraulic oil pump assembly (14), the control console (15) and the electrical assembly (16) are distributed around the crawler chassis (11) to form a space in the middle of the crawler chassis (11) for folding a multi-axis mechanical arm (12); the multi-axis mechanical arm (12) is folded on the crawler chassis (11) so that the drilling rig (100) can pass through a low passage.

4. The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method according to claim 1, 2 or 3, characterized in that: The rotary jet flow divider (41) comprises a flow divider housing (41-1) and a rotating shaft (41-2) that can rotate freely in the flow divider housing (41-1); the rotating shaft (41-2) can be installed on a power head assembly (200), and the power head assembly (200) drives the rotating shaft (41-2) to rotate; the rotary jet drill rod (43) has a vacuum back-suction channel (43a), a high-pressure polymer channel and a high-pressure gas channel (43e); the vacuum back-suction channel (43a) is connected to the vacuum back-suction channel (43e) on the flow divider housing (41-1). The vacuum back-suction interface (41a) is connected to the vacuum back-suction pipeline; the high-pressure polymer channel is connected to the high-pressure polymer interface on the splitter housing (41-1); the high-pressure gas channel (43e) is connected to the compressed air interface (1e) on the splitter housing (41-1); at least two groups of dual-channel rotary jet nozzles (43-2) are axially spaced apart at the lower part of the rotary jet drill rod (43), and each group of dual-channel rotary jet nozzles (43-2) includes a high-pressure polymer nozzle (43-2a) and a A high-pressure gas nozzle (43-2b) is located on the periphery of the high-pressure polymer nozzle (43-2a), the high-pressure polymer nozzle (43-2a) is connected to the corresponding high-pressure polymer channel, and the high-pressure gas nozzle (43-2b) is connected to the corresponding high-pressure gas channel (43e); the vacuum back-suction device (44) has multiple layers of back-suction holes (44-1-2) connected to the vacuum back-suction channel (43a) of the jet-jet drill rod (43), and the vacuum back-suction device (44) is provided with wireless pressure sensors (44-2) in sequence from top to bottom. , a high-strength spring (44-3) and a sealing plunger (44-4), wherein a suction port (44-1-1) is provided below the sealing plunger (44-4), the sealing plunger (44-4) is sealed with the multi-layer suction hole (44-1-2), and the sealing plunger (44-4) can move up and down according to the change in the pressure of the polymer mixture in the ground to control the opening and closing and the opening amplitude of the multi-layer suction hole (4-1-2); the wireless pressure sensor (44-2) is connected to the ground mechanical equipment operating platform for controlling the start or close of the vacuum suction pipeline.

5. The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method according to claim 4 is characterized in that: The suction port (44-1-1) is arranged at the lower end of the rod body (44-1) of the vacuum suction device (44); the suction port (44-1-1) is internally threadedly connected with a spiral adjuster (44-5); the spiral adjuster (44-5) has a central through hole; the upper end of the spiral adjuster (44-5) abuts against the lower end surface of the sealing plunger (44-4); and the spiral adjuster (44-5) also has a screwing structure for facilitating adjustment operation.

6. The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method according to claim 4 is characterized in that: The vacuum back-suction channel (43a) is located at the center of the rotary jet drill rod (43), the high-pressure gas channel (43e) is located at the outermost side of the rotary jet drill rod (43), and the high-pressure polymer channel is located between the vacuum back-suction channel (43a) and the high-pressure gas channel (43e); the lower end of the rotary jet drill rod (43) is provided with a confluence block (43-3) for blocking the corresponding high-pressure polymer channel and the high-pressure gas channel (43e); the confluence block (43-3) is provided with a confluence ring groove (43-3-1) connected to the corresponding channel; the high-pressure polymer nozzle (43-2a) is respectively connected to the confluence ring groove (43-3-1) corresponding to the corresponding high-pressure polymer channel; and the high-pressure gas nozzle (43-2b) is respectively connected to the high-pressure gas channel (43e) or the confluence ring groove (43-3-1) corresponding to the high-pressure gas channel (43e).

7. The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method according to claim 4 is characterized in that: The upper end of the rotating shaft body (41-2) is provided with a stepped rotating joint (41-2-2), and a plurality of channels are correspondingly arranged on the stepped surface of the stepped rotating joint (41-2-2); the diverter housing (41-1) is provided with a stepped cavity adapted to the stepped rotating joint (41-2-2); the stepped surface of the stepped cavity is provided with a diverter groove corresponding to the corresponding channel; the vacuum back-suction interface (41a), the high-pressure polymer interface and the compressed air interface (41e) are respectively connected to the corresponding diverter grooves; and the step side walls of the stepped rotating joint (41-2-2) are also respectively provided with sealing steel rings (41-2-3) that are sealed with the inner side walls of the stepped cavity.

8. The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method according to claim 7 is characterized in that: The lower end of the rotary shaft body (41-2) is provided with a diverter joint (41-2-1) for connecting an extended drill rod (42) or a jet-jet drill rod (43); the two ends of the extended drill rod (42) are respectively provided with an extended drill rod upper joint (42-1) and an extended drill rod lower joint (42-2); the upper end of the jet-jet drill rod (43) is provided with a jet-jet drill rod upper joint (43-1); the diverter joint (41-2-1) is complementary in shape to the extended drill rod upper joint (42-1) and the jet-jet drill rod upper joint (43-1); the extended drill rod lower joint (42-2) is complementary in shape to the jet-jet drill rod upper joint (43-1); and the diverter joint (41-2-1), the extended drill rod upper joint (42-1), the extended drill rod lower joint (42-2) and the jet-jet drill rod upper joint (43-1) all adopt a stepped joint structure.

9. The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method according to claim 1, 2 or 3, characterized in that: The hole-opening drilling tool comprises a common drill rod (41') and a down-the-hole hammer drill bit (42'); the upper end of the common drill rod (41') is connected to a rotary jet flow divider (41); the down-the-hole hammer drill bit (42') is fixed to the lower end of the common drill rod (41'); and the centers of the common drill rod (41') and the down-the-hole hammer drill bit (42') are both provided with a debris suction channel.

10. The ultra-low clearance micro-space multiple high-pressure micro-disturbance rotary jet grouting construction method according to claim 1, 2 or 3, characterized in that: A plurality of stirring blades (43-4) are also provided on the outer wall of the jet-jet drill rod (43).

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