A low-return high-pressure rotary jet composite grouting method and equipment

Abstract

The present invention discloses a low-return grouting, high-pressure rotary jet composite grouting method and equipment, which includes the following steps: inserting a low-return grouting, high-pressure rotary jet composite drill tool connected to a drill rod into a hole sealer, and drilling downward for a first set distance, while simultaneously pressing cement-stabilized slurry from top to bottom toward the bottom of the hole to fill and grout a fixed pipe section of the first set distance; repeating the above steps until drilling downward to a target distance to form multiple sections of fixed pipes; utilizing the low-return grouting, high-pressure rotary jet composite drill tool to rotary jet high-pressure thixotropic cement-based slurry toward the fixed pipe to cut, stir, and grout the fixed pipe and the surrounding strata, while simultaneously lifting the drill rod and the low-return grouting, high-pressure rotary jet composite drill tool for a second set distance until the fixed pipe is completely grouted; and sealing the hole sealer. The static pressure grouting technology and the high-pressure pulsating rotary jet grouting technology are combined in time sequence to give full play to the advantages of the two grouting technologies, and composite grouting is performed to adapt to different construction strata conditions.

Description

Technical Field

[0001] The invention relates to the technical field of drilling and grouting, in particular to a low-return high-pressure rotary jet composite grouting method and equipment. Background Art

[0002] Currently, excessive precipitation during foundation construction causes pore water to drain from the soil, leading to slope instability during compression and settlement. This precipitation adversely impacts the surrounding environment, as ground settlement corresponds to groundwater level drop. The curved distribution of groundwater level drop inevitably causes uneven settlement of adjacent buildings, leading to cracks, tilting, and even collapse of pipelines. High pressure water levels can easily lead to sudden surges during construction in pits within pits, such as elevator shafts. The quality of anti-floating anchors in underground garages is difficult to guarantee, posing safety risks such as floating in basements. Currently, high-pressure jet grouting and anti-floating anchors are the primary methods used for water diversion. Static pressure grouting and high-pressure jet grouting are two of the most commonly used grouting techniques.

[0003] Among some related technologies, the advantage of high-pressure jet grouting technology is that it has better control over the flow of slurry. Most of the slurry is stirred and mixed with the stripped soil to consolidate into a rotary jet pile body. Only a small part of the slurry will spread outside the effective reinforcement range, and the slurry will replace some of the original fine soil particles, resulting in a high-strength pile body. High-pressure jet grouting technology can be directed and positioned according to design requirements for spraying, and can form cylindrical, plate-shaped or fan-shaped consolidation bodies to meet various design requirements. Compared with static pressure grouting, high-pressure jet grouting technology is applicable to more soil types and has a certain degree of complementarity. The grouting effect is best in sandy soils.

[0004] Conventional high-pressure jet grouting requires drilling to a predetermined depth using a geological drill, and then lowering the high-pressure jet grouting pipe to the bottom of the hole to start high-pressure jet grouting from bottom to top. The actual construction operation process is cumbersome and inefficient, and it cannot meet the engineering requirements under various complex conditions and will cause 20% to 30% of the return.

[0005] The use of slurry will have a serious impact on the surrounding environment and cause a large amount of resource waste, which is contrary to the purpose of green construction. It cannot achieve the expected reinforcement effect when there are large boulders or block (collapse) stone layers. The relevant underground structures need to be reinforced, drained and anti-floating.

[0006] Among other related technologies, static pressure grouting technology is based on the principles of air pressure, hydraulic pressure and electrochemistry. A slurry with strong curing properties is transported to the corresponding soil layer through a grouting pipe. The slurry replaces the space where air and moisture exist in the original soil particles or rock cracks through filling, compaction, penetration and splitting. The slurry will then undergo a curing reaction with the originally loose soil particles or rock cracks and finally bond them into a whole, thereby improving the physical and mechanical properties of the rock and soil.

[0007] The disadvantage of static grouting technology is that the flow range of the grouting slurry is poorly controlled. The slurry will disperse to areas outside the designed range, causing slurry leakage or slurry leakage, making it difficult to accurately control the reinforcement range. In order to effectively control the reinforcement range through static grouting, when reinforcing clay or fine sand layers, the slurry is mainly injected into the original soil layer through compaction and splitting. The consolidated body formed after reinforcement has low strength due to the uneven distribution of slurry, resulting in poor reinforcement effect and low economic benefits.

[0008] Therefore, when faced with soft, clay soil, fine sand layer, pebbles and other geological layers, how to effectively reinforce the foundation and prevent seepage is an urgent problem that needs to be solved. Summary of the Invention

[0009] The purpose of the present invention is to provide a low-return high-pressure rotary jet composite grouting method and equipment, which combines the static pressure grouting technology and the high-pressure pulsating rotary jet grouting technology in a time sequence to give full play to the advantages of the two grouting technologies, carry out composite grouting, adapt to different construction strata conditions, and solve the problems raised in the above background technology.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] A low-return high-pressure rotary jet composite grouting method comprises the following steps:

[0012] S1. Determine the target orifice position on the ground and install the orifice sealer centered at the target orifice position;

[0013] S2, inserting a low-return slurry and high-pressure rotary jet composite drilling tool connected to the drill pipe into the hole sealer, and drilling downward for a first set distance, while simultaneously pressing cement-stabilized slurry from top to bottom to fill and pour to form a fixed pipe section of the first set distance;

[0014] S3, repeat the steps of S2 until the drilling reaches the target distance, forming multiple sections of fixed pipes connected in series.

[0015] S4, using a low-return high-pressure rotary jetting composite drilling tool to rotary jet high-pressure thixotropic cement-based slurry toward the fixed pipe to cut, stir and inject the fixed pipe and the surrounding formation, while simultaneously raising the drill pipe and the low-return high-pressure rotary jetting composite drilling tool to a second set distance;

[0016] S5, repeating step S4 until the fixed tube is completely perfused;

[0017] S6. Remove the drill rod and the low-return slurry high-pressure rotary jet composite drilling tool, and perform a hole sealing treatment on the orifice sealer.

[0018] As a further solution of the present invention: wherein the cement stabilized slurry is pure cement slurry with added stabilizer;

[0019] The thixotropic cement-based slurry is prepared by stirring a mixed slurry of water, cement, bentonite and a thixotropic agent at a low speed; or,

[0020] The thixotropic cement-based slurry is prepared by mixing water, cement, bentonite mixed slurry, thixotropic agent, accelerating setting agent and water reducing agent at low speed.

[0021] As a further solution of the present invention, determining the target orifice position on the ground and installing the orifice sealer centered at the target orifice position specifically includes the following steps:

[0022] Drill a mounting hole at the target orifice location, then align the center hole of the orifice sealer with the mounting hole, and then vertically insert and drill downward; the center hole of the orifice sealer is used to pass the drill rod and the low-return slurry high-pressure jet grouting composite drilling tool;

[0023] Cast around the hole closure to secure its position;

[0024] Seal and plug the gap between the orifice sealer and the ground outside the target orifice;

[0025] A slurry recovery device is installed on the orifice sealer, and the slurry recovery device is used to recover the return slurry during the injection process.

[0026] As a further solution of the present invention: wherein, the orifice closer includes a base plate, a guide cylinder is provided around the base plate, and a positioning pile is connected to the inner thread of the guide cylinder, an orifice support tube is provided at the bottom of the base plate, and a center hole connected to the orifice support tube is provided at the top of the base plate; a liquid collecting cylinder connected to the slurry recovery device is also provided at the top of the base plate; an orifice ring connected to the orifice support tube is provided at the top of the base plate, and the orifice ring is for the drill rod to pass through; an air cushion ring is provided inside the orifice ring, and the air cushion ring is connected to the charging and discharging air pipe, and the air cushion ring is used to seal the gap between the orifice ring and the drill rod; a pressure pipe and a pressure relief pipe connected to the orifice support tube are provided at the top of the base plate and located on the periphery of the orifice ring.

[0027] As a further solution of the present invention: wherein, in the said S3 step, after each fixed pipe section of the first set distance is formed, the low-return slurry high-pressure rotary jet composite drill tool is moved up and down for re-injection, and at the same time, the hole slope is measured every time the set depth is drilled, and if the hole slope is greater than 1%, it is corrected.

[0028] As a further solution of the present invention: wherein, if an overhead or leaking stratum is encountered during the downward drilling process, the in-situ extrusion filling and grouting is continued until the extrusion pressure is greater than or equal to 1.5 MPa, and then the downward drilling is continued;

[0029] If the drilling stops during the downward drilling process, the low-return slurry high-pressure rotary jet composite drilling tool should be placed 0.5m above the drilling stop position;

[0030] If the downtime during the downward drilling process is longer than 3 hours, the low-return slurry and high-pressure rotary jet composite drilling tool shall be lifted to the ground and cleaned; when drilling again, additional piles shall be added next to the target hole position.

[0031] As a further solution of the present invention: wherein, in the step S5, after each grouting of the second set distance is completed, the low-return slurry high-pressure rotary grouting composite drill tool is moved up and down to perform re-grouting, and the drill rod is rotated and stirred at the same time.

[0032] A low-return high-pressure rotary jet composite grouting equipment is also proposed, which includes:

[0033] The geological rotary drilling rig is equipped with a drill rod, and the bottom of the drill rod is equipped with a low-return slurry high-pressure jet composite

[0034] drilling tools;

[0035] An orifice sealer, cast in the ground at the target orifice location;

[0036] During drilling, the drill rod and the low-return slurry high-pressure rotary jet composite drilling tool are provided with a hole sealer and drilled downward. The low-return slurry high-pressure rotary jet composite drilling tool is used to input cement-stabilized slurry during the drilling process and input thixotropic cement-based slurry during the high-pressure grouting process.

[0037] As a further solution of the present invention: wherein, the low-return slurry and high-pressure rotary jet composite drilling tool comprises: a converter, one end of which is connected to the drill rod and the other end of which is connected to the drill bit;

[0038] A feed channel is vertically arranged in the converter and connected to a transmission channel in the drill pipe, wherein the transmission channel in the drill pipe is used to accommodate a slurry delivery pipeline;

[0039] A first telescopic plug assembly, the plug of which is arranged in the feed flow channel and the bottom end of which is telescopic in the vertical direction;

[0040] A U-shaped branch channel, both ends of which are connected to the blocked feed channel;

[0041] The low-return slurry perfusion channel is connected to the blocked lower space of the feed channel and is connected to the outside world; the low-return slurry perfusion channel is blocked by the output portion of the first telescopic plug assembly under normal conditions;

[0042] A high-pressure perfusion channel is provided within the converter and below the feed channel; a high-pressure nozzle is provided outside the converter and communicates with the high-pressure perfusion channel; the high-pressure nozzle comprises a first tube body connected to the converter, a second tube body is provided outside the first tube body, a mounting head is connected to an end of the second tube body away from the first tube body, a rotating nozzle is coaxially connected to the mounting head, and the rotating nozzle is communicated with the interior of the second tube body;

[0043] A vertical connecting channel connects the lower space of the feed flow channel with the high-pressure perfusion flow channel;

[0044] The second telescopic plug assembly is arranged in the high-pressure perfusion channel and is horizontally telescopic. The second telescopic plug assembly is used to block or open the bottom of the vertical connecting channel.

[0045] As a further solution of the present invention: it also includes a high-speed pulping machine, a double-layer pulp storage machine and a pipeline booster pump connected in sequence; the pipeline booster pump is connected to a high-pressure pulsating grouting pump and a high-pressure jet grouting pump, the high-pressure pulsating grouting pump is connected to the low-return high-pressure rotary jet composite drilling tool through the drill pipe integrated slurry supply pipe, and the high-pressure jet grouting pump is connected to the low-return high-pressure rotary jet composite drilling tool through the high-pressure jet composite grouting slurry supply pipe.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The low-return high-pressure rotary jet composite grouting method and equipment realizes the switching of the flow path through the coordination of the extension and contraction of the first telescopic plug assembly and the second telescopic plug assembly, so as to cooperate with the different slurries required in the composite grouting process, so as to combine the static pressure grouting technology and the high-pressure pulsating rotary jet grouting technology in time sequence to give full play to the advantages of the two grouting technologies.

[0048] 2. The low-return high-pressure rotary jet composite grouting method and equipment continuously presses cement-stabilized slurry into the hole bottom in a pulsed manner during the drilling and grouting process, and cooperates with the hole sealer cement-stabilized slurry to perform high-pressure in-situ filling and grouting of the grouting formation from top to bottom according to a certain instantaneous impact pressure, forming a composite grouting network vein structure; using strong thixotropic cement-based slurry as high-pressure jet grouting slurry, fully utilizing the low dynamic shear strength and high water seepage characteristics of the strong thixotropic cement-based slurry, and cooperating with the drilling and grouting to form a solid hole The fixed tube and the thixotropic cement-based slurry have a viscous self-sealing effect. After the strong thixotropic cement-based slurry is sprayed out through the nozzle in the form of a high-pressure jet flow, it not only performs high-pressure jet cutting, stirring and grouting on the soft strata within the pile-forming range, but also has the effect of compacting and splitting and grouting the soft strata outside the pile-forming range in the direction of the high-pressure jet flow, forming a high-pressure spraying composite grouting structure for soft strata; in order to increase the scope of use, it can effectively reinforce and prevent seepage on the foundation when facing soft, sticky soil, fine sand layer, pebble and other geological layers.

[0049] 3. The low-return high-pressure rotary jet composite grouting method and equipment adopts an orifice sealer including a base plate, with positioning and driving piles provided around the base plate, an orifice support tube provided at the bottom of the base plate, and a center hole connected to the orifice support tube provided at the top of the base plate; a liquid collecting cylinder connected to a slurry recovery device is also provided at the top of the base plate, which is convenient for driving and sealing the orifice, and also convenient for the up and down movement of the drill rod and the low-return high-pressure rotary jet composite drilling tool.

[0050] 4. The low-return high-pressure rotary jet composite grouting method and equipment, the first telescopic plug assembly and the second telescopic plug assembly both include an electric push rod and a plugging elastic ball, the elasticity of the plugging elastic ball is used to achieve sealing and plugging, and the electric push rod moves the plugging elastic ball. The electric push rod communicates with the external control device through wireless signals.

[0051] It can be operated in the same position, which facilitates the conversion of flow path. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a schematic diagram of the overall structure of the low-return slurry and high-pressure rotary jet composite drilling tool of the present invention;

[0053] Figure 2 Schematic diagram of the internal structure of the low-return slurry and high-pressure rotary jet composite drilling tool of the present invention;

[0054] Figure 3 Schematic diagram of the structure of the orifice sealer of the present invention;

[0055] Figure 4 It is a structural schematic diagram of the above-ground equipment in the present invention;

[0056] Figure 5 This is a schematic diagram of forming a fixed tube in the present invention;

[0057] Figure 6 Schematic diagram of high-pressure rotary sprinkler irrigation in the present invention;

[0058] Figure 7 This is another structural schematic diagram of the high-pressure nozzle in the present invention.

[0059] The corresponding relationship between the illustration labels and component names in the figure is as follows:

[0060] 1. Orifice sealer; 100. Base plate; 101. Positioning and piling; 102. Orifice support tube; 103. Liquid collecting cylinder; 104. Guide cylinder; 105. Orifice ring; 106. Air cushion ring; 107. Gas charging and discharging pipe; 108. Pressure pipe; 109. Pressure relief pipe; 2. Low-return slurry and high-pressure jetting composite drilling tool; 200. Converter; 201.

[0061] Drill bit; 202, feed flow channel; 203, first telescopic plug assembly; 204, U-shaped diversion channel; 205, low return grouting flow channel; 206, high-pressure grouting flow channel; 207, high-pressure nozzle; 2071, first tube body; 2072, second tube body; 2073, mounting head; 2074, rotating nozzle; 208, vertical connecting channel; 209, second telescopic plug assembly; 3, drill pipe; 4, geological rotary drilling rig; 5, high-speed slurry making machine; 6, pipeline booster pump; 7, high-pressure pulsating grouting pump; 8, high-pressure jet grouting pump; 9, drill pipe integrated slurry supply pipe; 10, high-pressure jet composite grouting slurry supply pipe; 11, double-layer slurry storage machine. DETAILED DESCRIPTION

[0062] See also Figures 1 to 6 A low-return high-pressure rotary jet composite grouting method and equipment combines static pressure grouting technology and high-pressure pulsating rotary jet grouting technology in a time sequence to give full play to the advantages of the two grouting technologies and perform composite grouting to adapt to different construction strata conditions and solve the problems raised in the above background technology.

[0063] See also Figure 1 - Figure 4 , a low-return high-pressure rotary jet composite grouting equipment, comprising:

[0064] A geological rotary drilling rig 4 is provided with a drill rod 3, the bottom end of which is installed with a low-return slurry high-pressure rotary grouting composite drilling tool 2; a hole sealer 1 is cast at the target hole position on the ground; when drilling, the drill rod 3 and the low-return slurry high-pressure rotary grouting composite drilling tool 2 pass through the hole sealer 1 and drill downward, and the low-return slurry high-pressure rotary grouting composite drilling tool 2 is used to input cement-stabilized slurry during the drilling process and input thixotropic cement-based slurry during the high-pressure grouting process.

[0065] Among them, the low-return slurry and high-pressure rotary jet composite drilling tool 2 includes:

[0066] The converter 200 is connected to the drill pipe 3 at one end and the drill bit 201 at the other end; the feed channel 202 is vertically arranged in the converter 200 and connected to the transmission channel in the drill pipe 3, and the transmission channel in the drill pipe 3 is used to accommodate the slurry delivery pipeline; the first telescopic plug assembly 203 is sealed in the feed channel 202, and its bottom end is vertically telescopic; the U-shaped branch channel 204, the two ends of which are connected to the blocked feed channel 202; the low return slurry perfusion channel 205, which is connected to the blocked lower space of the feed channel 202 and is connected to the outside world; the low return slurry perfusion channel 205 ... Under normal circumstances, channel 205 is blocked by the output part of the first telescopic plug assembly 203; the high-pressure perfusion channel 206 is arranged in the converter 200 and is located below the feed channel 202; a high-pressure nozzle 207 connected to the high-pressure perfusion channel 206 is provided outside the converter 200; a vertical connecting channel 208 connects the lower space of the feed channel 202 with the high-pressure perfusion channel 206; a second telescopic plug assembly 209 is arranged in the high-pressure perfusion channel 206 and is horizontally telescopic. The second telescopic plug assembly 209 is used to block or open the bottom of the vertical connecting channel 208.

[0067] The structure of the high-pressure nozzle 207 can be a commonly used nozzle structure, or can be set to the following structure:

[0068] It includes a first tube body 2071 connected to the converter 200, a second tube body 2072 is provided on the outer surface of the first tube body 2071, and a mounting head 2073 is connected to the end of the second tube body 2072 away from the first tube body 2071. A rotating nozzle 2074 is coaxially connected to the mounting head 2073, and the rotating nozzle 2074 is communicated with the interior of the second tube body 2072. Such a configuration allows the second tube body 2072 to be rotated by the fluid pressure during the jet drilling process.

[0069] The relative movement between the nozzle 2072 and the first tube 2071 allows the rotating nozzle 2074 to move away from the low-return high-pressure rotary jet composite drilling tool 2, so as to get closer to the soil layer and increase the working range. In addition, the rotating nozzle 2074 rotates during the jetting process, further enhancing the jetting range of the soil.

[0070] Among them, the bottom of the drill bit 201 can also be provided with three low-pressure grouting holes, three cutting blades, and two reinforced drill teeth in the center. The three low-pressure grouting holes are the grouting holes during low-pressure grouting, which are connected to the low-return grouting flow channel 205 through another flow channel. The three cutting blades destroy the soil when drilling downward, and have the function of drilling and grouting at the same time, so that grouting can be carried out at the upper and lower parts of the low-return grouting and high-pressure rotary jet composite drilling tool 2.

[0071] The drill rods (3) are made from 59mm diameter drill rods into short lengths of 10-20 meters, facilitating segmented operation and data recording. External connectors are used to connect the drill rods. Hemp seals are used to seal adjacent drill rods.

[0072] The first and second telescopic plug assemblies 203 and 209 each include an electric push rod and a sealing elastic ball. The elasticity of the sealing elastic ball is utilized to achieve a sealed seal, and the electric push rod moves the sealing elastic ball. The electric push rod communicates with an external control device via wireless signals, thereby facilitating the switching of the flow path.

[0073] During low-pressure grouting while drilling, forming a fixed pipe with a reticular structure between the borehole wall and the bottom layer, the first telescopic plug assembly 203 is retracted, blocking the lower space between the low-pressure grouting channel 205 and the feed channel 202. The second telescopic plug assembly 209 is extended, blocking the bottom of the vertical connecting channel 208. The flow path is: upper space of the feed channel 202 - U-shaped diverter 204 - lower space of the feed channel 202 - low-pressure grouting channel 205. The U-shaped diverter 204 and the first telescopic plug assembly 203 ensure that the injected grout is only allowed to flow from top to bottom, preventing grouting within the pipe during low-pressure grouting and reducing resource waste.

[0074] During high-pressure rotary grouting, the first telescopic plug assembly 203 is in an extended state, and the second telescopic plug assembly 209 is in a contracted state; the low return grouting flow channel 205 is blocked, and the vertical connecting channel 208 is

[0075] The bottom is open to allow the high-pressure injection channel 206 to flow into.

[0076] Through the above settings, the extension and contraction of the first telescopic plug assembly 203 and the second telescopic plug assembly 209 are coordinated to achieve the switching of the flow path, so as to cooperate with the different slurries required in the composite grouting process, so as to combine the static pressure grouting technology and the high-pressure pulsating rotary jet grouting technology in time sequence to give full play to the advantages of the two grouting technologies.

[0077] like Figure 3 The orifice closure device 1 shown

[0078] The orifice sealer 1 includes a base plate 100, which is provided with a guide cylinder 104 around the base plate 100, and the guide cylinder 104 is internally threaded with a positioning pile 101, the bottom of the base plate 100 is provided with an orifice support tube 102, and the top of the base plate 100 is provided with a center hole connected to the orifice support tube 102; the top of the base plate 100 is also provided with a liquid collecting cylinder 103 connected to the slurry recovery device; the top of the base plate 100 is provided with an orifice ring 105 connected to the orifice support tube 102, and the orifice ring 105 is for the drill rod 3 to pass through; an air cushion ring 106 is provided in the orifice ring 105, and the air cushion ring 106 is connected to the charging and discharging air pipe 107, and the air cushion ring 106 is used to seal the gap between the orifice ring 105 and the drill rod 3; a pressure pipe 108 and a pressure relief pipe 109 connected to the orifice support tube 102 are provided on the top of the base plate 100 and located on the periphery of the orifice ring 105. The orifice sealer 1 seals the borehole formed by drilling, creating an enclosed space that allows slurry to diffuse around the borehole, resulting in pressure penetration, splitting, and solidification, or compaction and splitting injection. The inclusion of a pressure pipe 108 and a pressure relief pipe 109 simultaneously manages the slurry return pressure control during both the vertical and rotational movement of the drill pipe 3 during the drilling and injection process. The air cushion ring 106 ensures a sealed underground borehole. The liquid collection barrel 103 collects waste liquid or slurry during the pressure relief operation.

[0079] like Figure 4 As shown in the figure, the equipment used in the construction of low-return grouting and high-pressure jet grouting piles mainly uses conventional light drilling and grouting equipment, and is combined with special equipment for composite grouting. The details are as follows:

[0080] The high-speed slurry making machine 5, the double-layer slurry storage machine 11 and the pipeline booster pump 6 are connected in sequence; the pipeline booster pump 6 is connected to the high-pressure pulsating grouting pump 7 and the high-pressure jet grouting pump 8, the high-pressure pulsating grouting pump 7 is connected to the low-return high-pressure rotary jet composite drilling tool 2 through the drill pipe integrated slurry supply pipe 9, and the high-pressure jet grouting pump 8 is connected to the low-return high-pressure rotary jet composite drilling tool 2.

[0081] The high-pressure jet composite grouting slurry supply pipe 10 is connected to the low-return high-pressure rotary jet composite drilling tool 2.

[0082] High-speed pulping machine 5: This is a self-made, vertical structure with a main shaft speed of 40-60 rpm and a 55 kW motor. The pulping machine is a high-speed vortex pulping machine with a pulping capacity of ≥400 L / min. The mixing drum volume is 1 m³ and the mixing capacity is 10-15 m / h. Each set of composite grouting equipment is equipped with one mixer.

[0083] Double-layer slurry storage machine 11: In the actual grouting process, according to the complexity of the stratum and the requirements of the reinforcement technology, the slurry that needs to be injected in the high-pressure rotary jet stage is cement paste, which has a high concentration and extremely poor flow performance. The grouting pumps commonly used on the market have limited slurry suction capacity, which will cause the entire grouting system to work poorly or even unable to work normally. Combined with the new low-return high-pressure rotary jet composite grouting process, a double-layer slurry storage machine 11 with a spiral conveying device is used, so that the discharge of the slurry has a certain pressure, which indirectly reduces the slurry suction load of the grouting pump, better meets the requirements of cement paste construction, and the single-cylinder volume is not less than 200L

[0084] Pipeline booster pump 6: Its head is 5~15m, displacement is 80~150L / min, it can pump out cement-based slurry with fluidity ≤150mm, and is a slurry pump with strong thixotropic properties.

[0085] High-pressure pulsating grouting pump 7: Its pump pressure is greater than 5MPa, flow rate is greater than 60L / min, and pulse frequency and pulse volume can be adjusted

[0086] High-pressure jet grouting pump 8: Its pumping capacity is ≥80L / min, grouting pressure is ≥30MPa, and it is a grouting pump capable of grouting cement slurry with a water-cement ratio of ≤0.5:1.

[0087] Other auxiliary equipment, which are equipment in related technologies: other auxiliary equipment include high-pressure hoses, orifice grouting devices, pressure gauges, flow meters, etc. High-pressure hoses are pipelines for conveying high-pressure slurry. The hoses used for composite grouting are generally hoses wound with 5 layers of steel wire. The manufacturer is Guangzhou Tianhe Hose Factory. The inner diameters are 22mm and 25mm. They are connected with embedded threaded high-pressure copper pipe joints, and the working pressure resistance is 40MPa. Each set needs to be equipped with about 100m of high-pressure hose. Orifice grouting device: The orifice grouting device adopts a single pipe joint for single-liquid grouting. The upper thread is made of a steel pipe with a diameter of 75mm, and a reducer is used to connect to the high-pressure pipe joint.

[0088] Pressure gauge and flow meter: The composite grouting pressure gauge is an essential instrument. The pressure gauge uses a seismic-resistant pressure gauge produced by Baoji Instrument Factory. It can be used to measure liquids with high viscosity and easy to form products, such as cement slurry and water glass. The flow meter is used to measure the slurry flow rate during the grouting process. It uses an LD type electromagnetic flow meter.

[0089] The present application also provides a low-return high-pressure rotary jet composite grouting method, which utilizes the above-mentioned equipment to work and includes the following steps:

[0090] S1. Determine the target orifice location on the ground and install the orifice sealer 1 centered at the target orifice location. Prior to this, complete preparatory work, including equipment installation and commissioning. Ensure that the on-site grouting material is adequately supplied and weighed and mixed in strict accordance with the slurry test results. Move the geological rotary drill rig 4 to the quasi-target orifice location. Before commencing grouting, debug the geological rotary drill rig 4 and the low-return high-pressure rotary jet composite drill rig 2. Ensure that the flow and pressure of the pulse high-speed slurry maker 5, double-layer slurry storage machine 11, and pipeline booster pump 6, connected to the high-pressure pulse grouting pump 7 and high-pressure jet grouting pump 8, meet the design standards. Check the sealing rings at the joints for proper sealing. After confirming that all equipment is functioning properly, use a spirit level to check the levelness of the drill rig to ensure that the drill rod 3 can be drilled vertically. Use a tape measure to measure the length of the drill rod 3 and number it according to the drilling sequence to ensure that the multifunctional drilling tool assembly can ultimately reach the designed depth.

[0091] S2. Insert the low-return slurry and high-pressure rotary jet composite drilling tool 2 connected to the drill pipe 3 through the hole sealer 1 and drill downward for a first set distance. Simultaneously, press cement-stabilized slurry from top to bottom to fill and pour to form a fixed pipe section of the first set distance.

[0092] S3, repeat the steps of S2 until the target distance is reached, forming multiple sections of fixed pipes connected in series. Figure 5 The state shown, where the geological layer is A

[0093] S4, using the low-return high-pressure rotary jet composite drilling tool 2 to rotate and jet high-pressure thixotropic cement-based slurry toward the fixed pipe to cut, stir and inject the fixed pipe and the surrounding formation, while simultaneously lifting the drill rod 3 and the low-return high-pressure rotary jet composite drilling tool 2 to a second set distance; Figure 6 The state shown, where the geological layer is A.

[0094] S5, repeat the steps of S4 until the fixed tube is completely perfused;

[0095] S6. Remove the drill rod 3 and the low-return slurry high-pressure rotary jet composite drilling tool 2, and seal the hole sealer 1.

[0096] According to the above steps, the drilling and static pressure grouting technology are organically integrated. During the drilling and grouting process, the cement-stabilized slurry is continuously pressed into the bottom of the hole in a pulse manner, and the cement-stabilized slurry of the hole sealer 1 is combined with a certain instantaneous impact pressure to perform high-pressure in-situ filling and grouting of the grouting formation from top to bottom in sequence, forming a pulse pressure-infiltration, squeezing-splitting, and solidification composite grouting network vein structure, namely a fixed pipe, thereby greatly improving the uniformity, controllability and effectiveness of the grouting of the pebble formation.

[0097] Strong thixotropic cement-based slurry is used as the high-pressure jet grouting slurry, fully utilizing the low dynamic shear strength and high water seepage characteristics of the strong thixotropic cement-based slurry, and coordinating with the fixed tube formed by the drilled grouting hole and the viscous self-sealing effect of the thixotropic cement-based slurry. After the strong thixotropic cement-based slurry is ejected through the nozzle in the form of a high-pressure jet stream, it not only performs high-pressure jet cutting, stirring and grouting on the soft strata within the pile range, but also has the effect of compacting and splitting and grouting the soft strata outside the pile range in the direction of the high-pressure jet stream, forming a high-pressure jet extrusion composite grouting structure for the soft strata.

[0098] In some preferred embodiments, the cement stabilized slurry is pure cement slurry with stabilizer added; the thixotropic cement-based slurry is prepared by stirring a mixed slurry of water, cement, bentonite and a thixotropic agent at a low speed; or,

[0099] Thixotropic cement-based slurry is prepared by low-speed stirring of water, cement, bentonite mixed slurry, thixotropic agent, accelerating agent and water reducing agent.

[0100] The above considerations for the selection of cement-stabilized slurry and thixotropic cement-based slurry are as follows:

[0101] The main grouting material is cement, which is the most commonly used grouting material because of its low price, wide distribution and good fluidity. Conventional Portland cement is usually used in most projects, but the specific type and strength grade of cement should be determined according to the needs of the actual project. The strength grade of Portland cement can be 325 or above, and the quality of cement should meet the requirements of "General Portland Cement" GB175-2007. In practical projects, damp or expired cement must not be used.

[0102] Special cements can be used under unusual geological conditions or when special requirements are met. The Technical Specification for Building Foundation Treatment (G179-2012) states that the water-cement ratio of cement slurry used for grouting must be based on the actual design, with a range of 0.8 to 12. A water-cement ratio less than 0.8 may clog the grouting pipes and nozzles, preventing grouting. A water-cement ratio greater than 1.2 may result in the consolidated strength failing to meet design and specification requirements.

[0103] Different cement slurries are used for grouting during the drilling and grouting phase and the high-pressure jet grouting phase. The drilling and grouting phase requires grouting the entire formation to form a dense hole wall, necessitating the use of a stable cement slurry. The slurry's stability primarily affects the various chemical reactions of the cementitious material, directly impacting the adhesion properties of the pile and, consequently, the overall quality of the pile. Stability specifically refers to the absence of segregation of the cement slurry during initial setting, good diffusion of the cementitious material within the slurry, and the maintenance of slurry properties after pulsating grouting. This means the slurry exhibits excellent physical and chemical stability. Stability can be measured chemically using the water extraction rate. This involves adding stabilizers, such as bentonite or other highly plastic clays, to pure cement slurry. During the high-pressure rotary jet grouting stage, a thixotropic cement paste is used, which is formed by adding a thixotropic agent to a mixed slurry of water, cement, and bentonite and stirring it at a low speed. During the high-pressure rotary jet grouting process, the low dynamic shear strength, high-pressure water seepage and static viscosity of the thixotropic cement paste need to be utilized. Due to the low dynamic shear strength of the thixotropic cement paste, it can break the gel instantly under high pressure, so it has good pumpability and less pipeline loss; the high-pressure water seepage and static viscosity of the thixotropic cement paste can effectively control the diffusion range of the slurry and prevent the occurrence of slurry backflow.

[0104] If there are special requirements or in the case of special grouting strata, it is necessary to conduct on-site tests on the selected cement slurry to verify its applicability. The following admixtures can be added to the slurry:

[0105] The first admixture uses accelerating agent, calcium chloride, water glass, etc.;

[0106] The second type of admixture is water reducer, lignin sulfur salt water reducer, naphthalene high efficiency water reducer, etc.

[0107] For other admixtures, they need to be dissolved in water to form admixture solution before adding. The type and proportion of the added admixtures need to be determined after indoor slurry experiment verification before engineering application.

[0108] In some preferred embodiments, determining the target orifice position on the ground and aligning and installing the orifice sealer 1 at the target orifice position specifically include the following steps:

[0109] Drill a mounting hole at the target orifice position, then align the center hole of the orifice sealer 1 with the mounting hole, and then insert it vertically downward; the center hole of the orifice sealer 1 is used to pass the drill rod 3 and the low-return high-pressure jet grouting composite drilling tool 2

[0110] Casting is performed around the orifice sealer 1 to fix its position;

[0111] Sealing and plugging the gap between the orifice sealer 1 and the ground outside the target orifice;

[0112] A slurry recovery device is installed on the orifice sealer 1 to recover slurry returned during the injection process. The orifice sealer 1 comprises a base plate 100, with positioning pilings 101 arranged around the perimeter. An orifice support tube 102 is located at the bottom of the base plate 100, and a central hole is located at the top of the base plate 100, connected to the orifice support tube 102. A liquid collecting cylinder 103, connected to the slurry recovery device, is also located at the top of the base plate 100. The slurry recovery device utilizes equipment from related art, such as CN110984142A.

[0113] The structure of the hole sealer 1 facilitates the insertion and sealing of the hole, and also facilitates the up and down movement of the drill rod 3 and the low-return slurry high-pressure rotary jet composite drilling tool 2.

[0114] In some preferred embodiments, in step S3, after each fixed pipe section of the first set distance is formed, the low-return slurry high-pressure rotary jet composite drill 2 is moved up and down for re-injection, and the hole slope is measured once every time the set depth is drilled. If the hole slope is found to be greater than 1%, it needs to be corrected.

[0115] Among them, if overhead or leakage formations are encountered during the downward drilling process, the original position will be maintained for squeezing and filling until the squeezing pressure is ≧1.5MPa, and then the downward drilling will be continued; if the downward drilling process is stopped, the low-return slurry and high-pressure rotary jet composite drill tool 2 will be placed 0.5m above the stop drilling position; if the downward drilling process is stopped for more than 3 hours, the low-return slurry and high-pressure rotary jet composite drill tool 2 will be lifted to the ground and cleaned. After drilling again, additional piles need to be placed next to the target hole position.

[0116] The end of step S2 can also refer to the following method: the end condition of the maximum grouting volume, when the maximum grouting volume is

[0117] When the local force > grouting bed force > minimum grouting pressure, and the grouting volume = maximum grouting volume (special case: grouting pressure < minimum grouting pressure, and grouting volume = 1.5*maximum grouting volume), the grouting section can be ended.

[0118] End condition of maximum grouting pressure: when the maximum injection volume > injection volume > minimum injection volume, and the grouting pressure = maximum grouting pressure, the grouting section can be ended.

[0119] In some preferred embodiments, in step S5, after each grouting of the second set distance is completed, the low-return slurry high-pressure rotary jet composite drilling tool 2 is moved up and down to perform re-grouting, and the drill rod 3 is rotated and stirred at the same time.

[0120] To avoid adverse effects on the embankment caused by excessive high-pressure grouting, a limited-volume, segmented grouting process is employed. The grouting pressure is no less than 22 MPa, and the grouting volume per 10-meter segment is 400 L. After each segment is completed, the grouting should be repeated two to three times with an upward and downward rotation to further expand the pile. High-pressure grouting is then performed sequentially from bottom to top, segment by segment, until the entire hole is completely filled. From bottom to top, high-pressure rotary grouting is performed segment by segment according to the designed process parameters (injection pressure, lifting speed, rotation speed, and slurry ratio), with the injection volume maintained according to the design requirements. Grouting is not concluded until the grouting pressure equals the specified pressure value and the injection volume exceeds the specified injection volume. After the high-pressure rotary grouting begins, personnel should check that the grouting parameters, such as the injection pressure, lifting speed, and rotation speed of the grouting pipe, are within the designed range and record them accordingly.

[0121] It should be understood that the orifice should be sealed throughout the low-return high-pressure rotary jet grouting process. After the grouting operation is completed, the grouting pipeline and equipment should be thoroughly cleaned. In particular, there should be no debris inside the low-return high-pressure rotary jet composite drilling tool 2 to prevent clogging. The cement slurry can be replaced with water for spraying to completely flush the equipment, and the waste slurry is discharged to the slurry recovery device for collection and reuse.

[0122] Working principle:

[0123] (1) Perform low slurry drilling and pouring to form a fixed network structure between the borehole wall and the bottom layer.

[0124] When the pipe is in operation, the first telescopic plug assembly 203 is in a contracted state, and the low return slurry injection channel 205 is connected to the feed channel.

[0125] The lower space of the feed channel 202 is blocked, and the second telescopic plug assembly 209 is extended, blocking the bottom of the vertical connecting channel 208. The flow path is: the upper space of the feed channel 202 - the U-shaped diverter channel 204 - the lower space of the feed channel 202 - the low-return grouting channel 205. The U-shaped diverter channel 204 and the first telescopic plug assembly 203 ensure that the injected slurry is only allowed to flow out from top to bottom, preventing grouting in the pipe during low-pressure grouting.

[0126] During high-pressure rotary jet grouting, the first telescopic plug assembly 203 is in an extended state, and the second telescopic plug assembly 209 is in a contracted state; the low return grouting channel 205 is blocked, and the bottom of the vertical connecting channel 208 is opened to allow fluid to flow into the high-pressure grouting channel 206.

[0127] Through the above settings, the extension and contraction of the first telescopic plug assembly 203 and the second telescopic plug assembly 209 are coordinated to achieve the switching of the flow path, so as to cooperate with the different slurries required in the composite grouting process, so as to combine the static pressure grouting technology and the high-pressure pulsating rotary jet grouting technology in time sequence, to give full play to the advantages of the two grouting technologies, to increase the scope of use, and to effectively reinforce and prevent the foundation when facing soft, sticky soil, fine sand layer, pebbles and other geological layers.

[0128] (2) During the drilling and grouting process, cement-stabilized slurry is continuously pressed into the bottom of the hole in a pulse manner, and the cement-stabilized slurry is used in conjunction with the hole sealer 1 to perform high-pressure in-situ filling and grouting of the grouting formation from top to bottom according to a certain instantaneous impact pressure, forming a pulse pressure-infiltration, squeezing, and solidification composite grouting network vein structure, namely a fixed pipe, thereby greatly improving the uniformity, controllability and effectiveness of the grouting of the pebble formation.

[0129] Using strong thixotropic cement-based slurry as high-pressure jet grouting slurry, making full use of the low dynamic shear strength and high water seepage characteristics of strong thixotropic cement-based slurry, coordinating with the fixed tube formed by the drilling and grouting hole and the viscous self-sealing effect of the thixotropic cement-based slurry, the strong thixotropic cement-based slurry is sprayed out through the nozzle in the form of a high-pressure jet flow, which not only performs high-pressure jet cutting, stirring and grouting on the soft strata within the pile range, but also has the effect of compacting and splitting the soft strata outside the pile range in the direction of the high-pressure jet flow, forming a soft

[0130] High-pressure spray composite grouting structure for weak formations.

[0131] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A low-return high-pressure rotary jet composite grouting method, characterized in that: It includes the following steps: S1. Determine the target orifice position on the ground, and install the orifice sealer (1) centered at the target orifice position; S2, inserting a low-return slurry and high-pressure rotary jet composite drilling tool (2) connected to the drill rod (3) from the hole sealer (1), and drilling downwards for a first set distance, while simultaneously pressing cement-stabilized slurry from top to bottom to form a fixed pipe section of the first set distance by filling and pouring; S3, repeating the step of S2 until drilling is started downward to the target distance, thereby forming multiple sections of fixed pipes connected in series up and down; S4, using a low-return slurry high-pressure rotary jet composite drilling tool (2) to rotary jet high-pressure thixotropic cement-based slurry toward the fixed pipe, so as to cut, stir and inject the fixed pipe and the surrounding strata, while simultaneously lifting the drill rod (3) and the low-return slurry high-pressure rotary jet composite drilling tool (2) to a second set distance; S5, repeating step S4 until the fixed tube is completely perfused; S6, remove the drill rod (3) and the low-return high-pressure jet grouting composite drill (2), and seal the orifice sealer (1); The low-return slurry and high-pressure rotary jet composite drilling tool (2) comprises: a converter (200), one end of which is connected to the drill rod (3) and the other end of which is connected to a drill bit (201); A feed channel (202) is vertically arranged in the converter (200) and connected to a transmission channel in the drill rod (3), wherein the transmission channel in the drill rod (3) is used to accommodate a slurry delivery pipeline; A first telescopic plug assembly (203) is provided for sealing in the feed flow channel (202), and its bottom end is telescopic in the vertical direction; A U-shaped branch channel (204), both ends of which respectively connect the blocked feed channel (202); The low-return slurry perfusion channel (205) is connected to the blocked lower space of the feed channel (202) and is also connected to the outside world; the low-return slurry perfusion channel (205) is blocked by the output portion of the first telescopic plug assembly (203) under normal conditions; A high-pressure perfusion channel (206) is provided in the converter (200) and is located below the feed channel (202); a high-pressure nozzle (207) is provided outside the converter (200) and is in communication with the high-pressure perfusion channel (206); the high-pressure nozzle (207) comprises a first tube (2071) connected to the converter (200); a second tube (2072) is provided outside the first tube (2071); an end of the second tube (2072) away from the first tube (2071) is connected to a mounting head (2073); a rotating nozzle (2074) is coaxially rotatably connected to the mounting head (2073); the rotating nozzle (2074) is in communication with the interior of the second tube (2072); A vertical connecting channel (208) connects the lower space of the feed channel (202) with the high-pressure perfusion channel (206); The second telescopic plug assembly (209) is arranged in the high-pressure perfusion flow channel (206) and is horizontally telescopic. The second telescopic plug assembly (209) is used to block or open the bottom of the vertical connection channel (208).

2. The low-return high-pressure rotary jet composite grouting method according to claim 1, characterized in that: The cement stabilized slurry is pure cement slurry with stabilizer added; The thixotropic cement-based slurry is prepared by stirring a mixed slurry of water, cement, bentonite and a thixotropic agent at a low speed; or the thixotropic cement-based slurry is prepared by stirring a mixed slurry of water, cement, bentonite, a thixotropic agent, an accelerating agent and a water reducing agent at a low speed.

3. The low-return high-pressure rotary jet composite grouting method according to claim 1, characterized in that: The method of determining a target orifice position on the ground and installing an orifice sealer (1) centered at the target orifice position specifically includes the following steps: A mounting hole is drilled at the target orifice position, and then the center hole of the orifice sealer (1) is aligned with the mounting hole, and then vertically inserted downward; the center hole of the orifice sealer (1) is used to pass the drill rod (3) and the low-return slurry high-pressure jet-jet composite drilling tool (2); Casting around the orifice sealer (1) to fix its position; Sealing and plugging the gap between the orifice sealer (1) and the ground outside the target orifice; A slurry recovery device is installed on the orifice sealer (1), and the slurry recovery device is used to recover the return slurry during the injection process.

4. The low-return high-pressure rotary jet composite grouting method according to claim 3, characterized in that: The orifice sealer (1) comprises a base plate (100), a guide cylinder (104) is provided around the base plate (100), a positioning pile (101) is connected to the guide cylinder (104) through an internal thread, an orifice support tube (102) is provided at the bottom of the base plate (100), and a center hole is provided at the top of the base plate (100) that is connected to the orifice support tube (102); a liquid collecting cylinder (103) connected to a slurry recovery device is also provided at the top of the base plate (100); and a central hole is provided at the top of the base plate (100) that is connected to the orifice support tube (102). The orifice ring (105) is connected to the tube (102), and the orifice ring (105) is for the drill rod (3) to pass through; an air cushion ring (106) is provided inside the orifice ring (105), and the air cushion ring (106) is connected to the air charging and discharging pipe (107), and the air cushion ring (106) is used to seal the gap between the orifice ring (105) and the drill rod (3); a pressurizing pipe (108) and a pressure relief pipe (109) connected to the orifice support tube (102) are provided on the top of the substrate (100) and located on the periphery of the orifice ring (105).

5. The low-return high-pressure rotary jet composite grouting method according to claim 1, characterized in that: In the step S3, after each fixed pipe section of the first set distance is formed, the low-return slurry high-pressure rotary jet composite drilling tool (2) is moved up and down to perform re-injection; at the same time, the hole slope is measured each time the set depth is drilled, and if the hole slope is greater than 1%, it is corrected.

6. The low-return high-pressure rotary jet composite grouting method according to claim 5, characterized in that: If you encounter overhead or leakage formations during the downward drilling process, keep the original position and perform the extrusion filling and grouting until the extrusion pressure is ≥1.5MPa, then continue to drill downwards; If the drilling stops during the downward drilling process, the return slurry high-pressure rotary jet composite drilling tool (2) is placed 0.5m above the drilling stop position; If the downtime during the downward drilling process is longer than 3 hours, the low-return slurry high-pressure jet-jet composite drilling tool (2) is lifted to the ground and cleaned; when drilling again, additional piles are placed next to the target hole position.

7. The low-return high-pressure rotary jet composite grouting method according to claim 1, characterized in that: In the step S5, after each grouting of the second set distance is completed, the low-return slurry high-pressure rotary jet composite drilling tool (2) is moved up and down to perform re-grouting, while the drill rod (3) is rotated and stirred.

8. A low-return high-pressure rotary jet composite grouting equipment, characterized in that: It includes: A geological rotary drilling rig (4) is provided with a drill rod (3), and a low-return slurry high-pressure rotary jet composite drilling tool (2) is installed at the bottom end of the drill rod (3); An orifice sealer (1) is cast at a target orifice position on the ground; During drilling, the drill rod (3) and the low-return slurry high-pressure rotary jet composite drilling tool (2) are passed through the hole sealer (1) and the hole is drilled downward; the low-return slurry high-pressure rotary jet composite drilling tool (2) is used to input cement-stabilized slurry during the drilling process and input thixotropic cement-based slurry during the high-pressure injection process; The low-return slurry and high-pressure rotary jet composite drilling tool (2) comprises: a converter (200), one end of which is connected to the drill rod (3) and the other end of which is connected to a drill bit (201); A feed channel (202) is vertically arranged in the converter (200) and connected to a transmission channel in the drill rod (3), wherein the transmission channel in the drill rod (3) is used to accommodate a slurry delivery pipeline; A first telescopic plug assembly (203) is provided for sealing in the feed flow channel (202), and its bottom end is telescopic in the vertical direction; A U-shaped branch channel (204), both ends of which respectively connect the blocked feed channel (202); The low-return slurry perfusion channel (205) is connected to the blocked lower space of the feed channel (202) and is also connected to the outside world; the low-return slurry perfusion channel (205) is blocked by the output portion of the first telescopic plug assembly (203) under normal conditions; A high-pressure perfusion channel (206) is provided in the converter (200) and is located below the feed channel (202); a high-pressure nozzle (207) is provided outside the converter (200) and is in communication with the high-pressure perfusion channel (206); the high-pressure nozzle (207) comprises a first tube (2071) connected to the converter (200); a second tube (2072) is provided outside the first tube (2071); an end of the second tube (2072) away from the first tube (2071) is connected to a mounting head (2073); a rotating nozzle (2074) is coaxially rotatably connected to the mounting head (2073); the rotating nozzle (2074) is in communication with the interior of the second tube (2072); A vertical connecting channel (208) connects the lower space of the feed channel (202) with the high-pressure perfusion channel (206); The second telescopic plug assembly (209) is arranged in the high-pressure perfusion flow channel (206) and is horizontally telescopic. The second telescopic plug assembly (209) is used to block or open the bottom of the vertical connection channel (208).

9. The low-return high-pressure rotary jet composite grouting equipment according to claim 8, characterized in that: The invention also includes a high-speed slurry making machine (5), a double-layer slurry storage machine (11), and a pipeline booster pump (6) connected in sequence; the pipeline booster pump (6) is connected to a high-pressure pulsating grouting pump (7) and a high-pressure jet grouting pump (8); the high-pressure pulsating grouting pump (7) is connected to a low-return slurry high-pressure rotary jet composite drilling tool (2) through a drill pipe integrated slurry supply pipe (9); and the high-pressure jet grouting pump (8) is connected to a low-return slurry high-pressure rotary jet composite drilling tool (2) through a high-pressure jet composite grouting slurry supply pipe (10).

Images