Free-angle soft soil foundation reinforcement construction equipment, construction method and reinforcement pile

Abstract

The present invention discloses a free-angle soft soil foundation reinforcement construction equipment, a construction method and a reinforcement pile, which belongs to the technical field of stratum engineering reinforcement construction. The free-angle soft soil foundation reinforcement construction equipment of the present invention includes a screwing machine, a hydraulic rotary power head, a rotary jet diverter and a reinforcement pile drilling tool. The free-angle rotating device can be used to drive piles obliquely, and reinforcement piles can be formed inside a building to improve the foundation strength inside the building. Through the improvement of the reinforcement pile drilling tool, the drilling tool can fully mix the cement slurry and the original foundation soil when sinking and lifting. The drilling tool has a better effect of cutting and crushing the soil, and is not prone to difficulty in advancing due to drilling sticking. The static pressure sensor can monitor the internal pressure, and the vacuum mud suction pipeline can be used to suck out the excess cement mixture, solving the problem of causing ground lifting and thus damaging the building and causing danger. At the same time, it can replace imported cement mixing pile machines, reducing equipment investment costs and construction costs.

Description

Technical Field

[0001] The present invention relates to a stratum engineering reinforcement construction technology, and more particularly to a free-angle soft soil foundation reinforcement construction device, a construction method and a reinforcement pile. Background Art

[0002] With the rapid development of urban construction, underground space in historic districts and old urban areas has been rapidly developed. This development of underground space requires the protection of adjacent older buildings, which often lack pile foundations, are susceptible to deformation, and are significantly affected by settlement. Consequently, foundation reinforcement is often required for older buildings. Common foundation reinforcement technologies used in the past include compaction grouting, deep cement mixing piles, and high-pressure jet jet piles.

[0003] 1. The technical principles and conventional construction methods of compaction grouting technology as well as existing problems and shortcomings.

[0004] (1) Principle of compaction grouting technology. Compaction grouting is the use of high pressure to inject high-concentration cement slurry or chemical slurry. At the beginning of grouting, the slurry always fills the larger gaps first, and then penetrates into the soil pores under greater pressure. As the pore water pressure of the soil layer increases, the soil is squeezed until shear cracks appear and splitting occurs. The slurry then fills the cracks to form slurry veins, forming a new network skeleton structure in the soil. During the formation process, the slurry veins occupy a part of the space in the soil, and the pores in the soil layer are penetrated by the slurry, thereby compacting the soil and forming a new slurry vein composite foundation, which improves the strength and anti-seepage performance of the soil. At the same time, it also changes the physical and mechanical properties of the soil and improves the bearing capacity of the soft soil foundation.

[0005] (2) Conventional construction method of compaction grouting. Compaction grouting is generally carried out around old buildings or inside old buildings. The construction mainly uses manpower and vibration machinery. A 2.2kw vibration motor is used to press the Φ25mm special black iron grouting pipe into the soil, leaving 100mm on the top. The second drill rod is connected and pressed into the stratum to the designed depth. Then, a SYB50 type squeeze grouting pump is used for grouting. The grouting is lifted from bottom to top according to the designed grouting pressure and grouting volume. The grouting pressure is controlled within 0.2-0.4MPa and the slurry flow rate is 0-45l / min. The grouting pipe pulling height is 0.33m.

[0006] (3) Problems and shortcomings of compaction grouting

[0007] Compression grouting mainly relies on the pressure of cement slurry to squeeze the soil, causing cracks in the soil. The slurry fills the cracks to form a slurry-vein composite foundation. This foundation is greatly affected by the soil layer. When encountering loose miscellaneous fill and sandy soil, the slurry is very easy to lose and cannot form a vein-shaped composite foundation.

[0008] Compaction grouting is primarily deployed along the perimeter of buildings. Due to pressure limitations, its impact is limited. Effective vein-shaped composite foundations cannot be formed within older buildings. Due to the lack of internal foundation improvements, older buildings are susceptible to disturbance and settlement deformation, which can lead to deformation and damage.

[0009] 2. The technical principles, conventional construction methods, existing problems and shortcomings of deep mixing pile technology.

[0010] (1) Technical principle of deep mixing piles: Deep cement mixing piles use cement as a curing agent. Through deep mixing machinery, soft soil or sand and the curing agent are forcibly mixed in the foundation to harden the soft foundation and improve the foundation strength.

[0011] (2) Conventional construction method of deep mixing pile technology:

[0012] Equipment used: Pile mixing machine: PH-5 series deep mixing pile machine and corresponding auxiliary equipment (mortar pump, mortar mixer, etc.).

[0013] First, prepare the cement slurry: mix the cement slurry according to the mix ratio determined by the design, and pour the cement slurry into the aggregate hopper before grouting.

[0014] The second step is pre-mixing and sinking: After the mixer's cooling water circulation is normal, start the mixer motor, loosen the crane wire rope, and allow the mixer to sink along the guide frame, mixing and cutting the soil. The sinking speed can be controlled by the motor's current monitoring meter, and the operating current should not exceed 40A. As the mixer sinks, start the mortar pump to press the cement slurry into the foundation, spraying and rotating it.

[0015] The third step is to lift the spraying and mixing. After the mixer sinks to the designed depth, start the mortar pump to press the cement slurry into the foundation, spraying and rotating at the same time, and lift the mixer strictly according to the lifting speed determined by the design.

[0016] The fourth step is to repeat the up and down mixing. When the mixer is lifted to the top elevation of the designed reinforcement depth, the cement slurry in the aggregate hopper should be emptied. In order to mix the soft soil and cement slurry evenly, the mixer is rotated and sunk into the soil again. After reaching the designed reinforcement depth, the mixer is lifted out of the ground. Cement slurry is sprayed during the mixing process to form a deep cement mixing pile.

[0017] (3) Problems and disadvantages of deep mixing piles:

[0018] Deep cement mixing piles are used to reinforce the foundation of old buildings. The piles can only be arranged around the building, and the foundation reinforcement can only be carried out vertically around the building. The foundation inside the building cannot be reinforced.

[0019] The grouting port of conventional cement mixing piles is located below the bottom of the drill bit. When the pile is lifted upward for spraying and mixing, the cement slurry is sprayed out and accumulates below. It cannot be stirred by the blades, and the soil cannot be reinforced. At the same time, it seriously wastes materials.

[0020] The mixing blades of conventional cement mixing piles are relatively simple and have a certain cutting angle. They are prone to causing problems such as drill sticking and difficulty in advancing when mixing soil.

[0021] Conventional domestic cement-soil mixing piles are currently unable to be used for diagonal construction and can only be used vertically. Imported IMS cement-soil mixing piles from Japan can be used for diagonal cement-soil mixing, but they are expensive and also have the aforementioned shortcomings and difficulties.

[0022] 3. The technical principles, conventional construction methods, existing problems and shortcomings of conventional high-pressure rotary jet pile technology.

[0023] (1) Technical principle of high-pressure jet grouting piles:

[0024] High-pressure jet cutting and breaking soil: The jet's pressure pulses through the soil, creating cavities and widening cracks. Mixing and stirring: As the drill pipe rotates and lifts, voids form behind the jet. Under the jet's pressure, soil particles are forced to move in the direction opposite to the nozzle's movement (i.e., the direction of less resistance), where they mix with the slurry to form a new structure. Lifting and displacement (triple-tube method): As the high-speed water jet cuts the soil, the compressed gas displaces some of the excised soil particles onto the ground. The remaining voids are then filled with cement slurry. Filling and infiltration consolidation: The high-pressure cement slurry rapidly fills the created grooves and voids between soil particles, consolidating them through water extraction. It can also penetrate a certain thickness of the sand layer to form a consolidated mass. Compaction: As the high-pressure jet cuts and breaks the soil, residual pressure remains at the edges of the broken areas, compacting the soil to a certain degree, making the edges of the jet-grouting pile more compressive than the center.

[0025] (2) Construction method of high-pressure jet grouting piles:

[0026] Position the drilling rig, prepare cement slurry, and drill holes (triple-tube method). When using a geological drilling rig for drilling, the drill bit drills a hole at the predetermined pile position to the designed elevation (the pre-drilled hole diameter is 15 cm). Inserting the pipe (single-tube method, double-tube method): When using a rotary jet grouting pipe for drilling operations, the two processes of drilling and inserting the pipe can be combined into one. When penetrating into the soil in the first stage, the penetration can be carried out with the help of the jetting or vibration of the jetting pipe itself. The process is as follows: start the drilling rig and simultaneously start the high-pressure mud pump to deliver cement slurry at low pressure, so that the drill rod vibrates along the guide frame and the jet forms a hole and sinks; until the pile bottom reaches the designed elevation, observe that the working current should not be greater than the rated value. After drilling with the triple-tube drilling rig, pull out the drill rod and insert the rotary jet pipe. During the insertion process, in order to prevent mud and sand from clogging the nozzle, a small pressure (0.5-1.0MPa) can be used to inject water while lowering the pipe. Lifting the shotcrete pipe and stirring: After the shotcrete pipe sinks to the designed depth, stop drilling and keep rotating. Increase the pressure of the high-pressure mud pump to the construction design value (20-40MPa). After 30 seconds of bottom spraying, continue spraying while rotating. At the same time, lift the drill pipe in strict accordance with the lifting speed determined by the design and test pile. If the double-pipe method or triple-pipe method is used for construction, after reaching the designed depth, connect the high-pressure water pipe and air pressure pipe, start the high-pressure clean water pump, mud pump, air compressor and drilling rig to rotate, and use instruments to control the pressure, flow and air volume. Start lifting when they reach the predetermined values, continue spraying and lifting until the expected reinforcement height is reached and stop, forming a high-pressure jet pile.

[0027] (3) Problems and shortcomings of high-pressure jet grouting piles:

[0028] Conventional high-pressure rotary jet piles with single, double and triple tubes all have high-pressure jet flow generated by high-pressure mud pumps acting on the soil, which increases the soil pressure and easily causes ground uplift, thereby damaging buildings and causing danger.

[0029] The diameter of high-pressure rotary jet piles is limited by the size of the high-pressure jet flow. The larger the high-pressure jet flow, the larger the pile diameter. However, due to the limited pressure of the high-pressure mud pump, the pile diameter is subject to certain restrictions.

[0030] High-pressure jet grouting piles act on the soil through high-pressure jets. Due to the unevenness of the soil, the pile diameter varies greatly in different soil layers and has a large discreteness.

[0031] Although high-pressure jet grouting piles can currently be constructed at an angle, the process requires disassembling the drill rod, and each section of the drill rod is relatively short, increasing labor and time. This is especially true during emergency projects, where quick-setting agents and two-component setting agents (such as water glass and cement slurry) are used. The water glass and cement slurry easily mix during drill rod disassembly, causing rapid solidification and clogging the pipe, rendering the drill rod useless and preventing further construction. Summary of the Invention

[0032] 1. Technical problem to be solved by the invention

[0033] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a free-angle soft soil foundation reinforcement construction equipment, construction method and reinforcement pile. By adopting the technical solution of the present invention, the free-angle rotating device can be used to drive piles obliquely, so that reinforcement piles can be formed inside the building, thereby improving the foundation strength inside the building. Cement mixing piles, high-pressure rotary jet piles or high-pressure rotary jet plus mixed cement composite high-bearing composite piles can be formed according to geological conditions and construction design requirements; through the improvement of the reinforcement pile drilling tool, the cement slurry and the original foundation soil can be fully mixed when the drilling tool is sunk and lifted, and the drilling tool has better effect in cutting and crushing the soil, and is not prone to difficulty in advancing due to stuck drilling; and the static pressure sensor can be used to monitor the internal pressure, and the vacuum mud suction pipeline can be used to suck out the excess cement mixture, thereby solving the problem of ground lifting and thus damaging the building and causing danger; at the same time, it can replace imported cement mixing pile machines, reducing equipment investment costs and construction costs.

[0034] 2. Technical solution

[0035] In order to achieve the above object, the technical solution provided by the present invention is:

[0036] The present invention provides a free-angle soft soil foundation reinforcement construction equipment, comprising a screwdriver, a hydraulic rotary power head, a jet grouting diverter, and a reinforced pile drilling tool. The screwdriver has a boom and a free-angle rotating device installed at the end of the boom. The free-angle rotating device is connected to the hydraulic rotary power head, and the hydraulic rotary power head is connected to the reinforced pile drilling tool via the jet grouting diverter. A plurality of extended drill rods are selectively provided between the jet grouting diverter and the reinforced pile drilling tool.

[0037] The bottom of the reinforced pile drilling tool is provided with a spiral stirring alloy drill bit, and a plurality of stirring blades are distributed axially at intervals on the outer side wall of the reinforced pile drilling tool. The stirring blades located at the bottom of the reinforced pile drilling tool or on the spiral stirring alloy drill bit are provided with a high-pressure cement slurry nozzle and a high-pressure water nozzle facing outwards, and the high-pressure cement slurry nozzle is connected to the high-pressure cement slurry interface on the rotary jet splitter through a high-pressure cement slurry pipeline, and the high-pressure water nozzle is connected to the high-pressure water interface on the rotary jet splitter through a high-pressure water pipeline; the reinforced pile drilling tool is provided with a lower low-pressure cement slurry nozzle and a lower compressed air nozzle respectively below the stirring blades, and the reinforced pile drilling tool is provided with a low-pressure cement slurry nozzle and a lower compressed air nozzle respectively below the stirring blades. An upper low-pressure cement slurry nozzle and an upper compressed air nozzle are respectively provided above the mixing blades on the pile drilling tool. The lower low-pressure cement slurry nozzle and the upper low-pressure cement slurry nozzle are connected to the low-pressure cement slurry interface on the rotary jet diverter through a low-pressure cement slurry pipeline; the lower compressed air nozzle and the upper compressed air nozzle are connected to the compressed air interface on the rotary jet diverter through a compressed air pipeline; the spiral stirring alloy drill bit is also provided with a solenoid valve and a static pressure sensor, the solenoid valve is connected to the mud suction interface on the rotary jet diverter through a vacuum mud suction pipeline, and the static pressure sensor is connected to the background control system through a signal line.

[0038] Furthermore, the upper end of the hydraulic rotary power head is provided with a pin seat for connecting the free angle rotation device; the rotary jet diverter includes an inner shaft tube and an outer sleeve, the outer sleeve is rotatably and sealedly sleeved on the inner shaft tube, and multiple independent fluid cavities are formed between the inner shaft tube and the outer sleeve; the lower end of the hydraulic rotary power head is axially inserted into the upper end of the inner shaft tube and fixedly connected by a first connecting pin, the lower end of the inner shaft tube is sleeved with a first flange seat, the first flange seat is fixedly connected to the lower end of the inner shaft tube by a second connecting pin, and the lower end of the first flange seat is also installed with a second flange seat.

[0039] Furthermore, a hydraulic telescopic drill rod is provided between the jet jet diverter and the adjacent extended drill rod or reinforced pile drilling tool.

[0040] Furthermore, a guide ring is fixedly provided on the outside of the reinforcement pile drilling tool. The guide ring is coaxially arranged with the reinforcement pile drilling tool, and the outer diameter of the guide ring is equivalent to the diameter of the circle formed by the mixing blade rotating around the drilling tool axis.

[0041] Furthermore, the outer side wall of the guide ring is provided with a spiral rib which is consistent with the spiral direction of the stirring blade.

[0042] Furthermore, the bottom of the spiral stirring alloy drill bit is provided with a pilot working portion, and the stirring blades on the periphery of the spiral stirring alloy drill bit are provided with a reaming working portion.

[0043] A free-angle soft soil foundation reinforcement construction method of the present invention comprises the following steps:

[0044] S1. Construction equipment assembly and preparation:

[0045] S1-1. Assemble the above-mentioned free-angle soft soil foundation reinforcement construction equipment to form a complete set of main construction equipment for high-pressure rotary grouting and mixing cement composite high-load reinforcement piles;

[0046] S1-2. Install an air compressor, a high-pressure fluid pump, an ultra-high-pressure fluid pump, an ultra-high-pressure water pump, a cement mixing backstage, and a computer control backstage, and connect them to the main construction equipment through pipelines; then move the main construction equipment to the pile position;

[0047] S1-3, prepare cement slurry on site through cement mixing background, and mix and transport cement slurry;

[0048] S1-4. Use the hydraulic motor to activate the free angle rotation device to adjust the angle of the reinforcement pile drilling tool;

[0049] S1-5. First, start the air compressor to perform a test air pressure injection to check whether the air pipeline is unobstructed; then start the high-pressure fluid pump and the ultra-high-pressure water pump to check whether the cement slurry pipeline and the water pipeline are unobstructed and whether the pressure meets the design requirements; then switch the high-pressure fluid pump to the ultra-high-pressure fluid pump and the ultra-high-pressure water pump, and recheck whether the cement slurry pipeline and the water pipeline are unobstructed and whether the pressure meets the ultra-high-pressure design requirements;

[0050] S2. Drilling and lifting of drilling tools:

[0051] S2-1. After confirming that all pipelines are unobstructed and the pressures have reached the design requirements, start the hydraulic rotary power head for rotary drilling;

[0052] S2-2. During the entire drilling and lifting process of the reinforced pile drill, the drill is rotated at a constant speed, and the drill is lowered and lifted at a constant speed. The mixed cement slurry is evenly and continuously injected through a high-pressure fluid pump during the lowering and lifting of the drill. The grouting pressure is controlled at 0.8MPa to 1.0MPa to ensure that the cement slurry is fully mixed with the original foundation soil. When making high-pressure jet grouting piles, high-pressure water is sprayed from an ultra-high-pressure water pump to cut and crush the soil while the drill is rotating. At the same time, the ultra-high-pressure fluid pump is started to perform ultra-high-pressure grouting to mix and stir the crushed soil.

[0053] S2-3. When making a composite pile with an enlarged head, the following steps are also included:

[0054] S2-3a. After the reinforced pile drill reaches the designed enlarged head position, reduce the drilling speed and rotation speed, and simultaneously increase the pressure of the ultra-high-pressure water pump to 40 MPa to 90 MPa. Use high-pressure, high-speed water to cut the soil outside the mixing blades, crushing and mixing it. At the same time, increase the pressure of the ultra-high-pressure fluid pump to 40 MPa to 90 MPa, and use high-pressure cement slurry to cut the soil outside the mixing blades for a second time, crushing and mixing it.

[0055] S2-3b. After reaching the bottom of the designed pile length, lift and jet grout the mixture, increasing the lifting speed appropriately. Within the expanded range, repeatedly increase the pressure of the ultra-high-pressure water pump to 40 MPa to 70 MPa. Use high-pressure, high-speed water to cut through the soil outside the mixing blades, crushing and mixing. At the same time, increase the pressure of the ultra-high-pressure fluid pump to 40 MPa to 70 MPa. Use high-pressure cement slurry to cut through the soil outside the mixing blades for a second time, crushing and mixing again, so that the diameter of the cement mixture reaches 1.5 m to 3 m.

[0056] S2-3c. Continue to elevate the reinforced pile drilling tool. When the elevation exceeds the range of the expansion body, appropriately reduce the pressure of the ultra-high pressure water pump and the ultra-high pressure fluid pump, cooperate with the mixing blades to cut, crush and mix the soil inside the mixing blades, and simultaneously increase the rotation speed and elevation speed of the drilling tool;

[0057] S2-4. After reaching the designed pile top elevation, lift the drill bit and use clean water to clean the cement slurry in the reinforced pile drill bit.

[0058] Furthermore, in step S2, the static pressure sensor is turned on, and the change in soil strength is sensed by the static pressure sensor, and transmitted to the background control system through the signal line, and the background control system adjusts the pressure of the high-pressure jet stream and the mixing ratio of the high-pressure jet stream; after the static pressure sensor detects that the pressure of the cement mixture at the spiral stirring alloy drill bit exceeds the set threshold, the background control system controls the solenoid valve to open and suck out the excess cement mixture through the vacuum mud suction pipeline.

[0059] Furthermore, in step S2, the sinking and lifting speeds of the reinforcement pile drilling tool are adapted to the pumping capacity of the fluid pump, and the sinking spraying volume is controlled to be 60% of the cement usage, and the lifting spraying volume is controlled to be 40% of the cement usage.

[0060] The free-angle soft soil foundation reinforcement pile of the present invention is formed by adopting the above-mentioned free-angle soft soil foundation reinforcement construction method. The formed reinforcement pile is a cement mixing pile or a high-pressure rotary jet pile or a composite pile with an enlarged body.

[0061] 3. Beneficial effects

[0062] Compared with the existing known technologies, the technical solution provided by the present invention has the following significant effects:

[0063] (1) The free-angle soft soil foundation reinforcement construction equipment, construction method and reinforcement piles of the present invention can be used to install piles obliquely through the free-angle rotating device, so as to form reinforcement piles inside the building, improve the foundation strength inside the building, and form cement mixing piles, high-pressure rotary jet piles or high-pressure rotary jet plus mixed cement composite high-load composite piles according to geological conditions and construction design requirements; through the improvement of the reinforcement pile drilling tool, the drilling tool can fully mix the cement slurry with the original foundation soil when sinking and lifting, and the drilling tool has a better effect of cutting and crushing the soil, and is not prone to difficulty in advancing due to sticky drilling; and the static pressure sensor can be used to monitor the internal pressure, and the vacuum mud suction pipeline can be used to suck out the excess cement mixture, thereby solving the problem of ground lifting, thereby damaging the building and causing danger; at the same time, it can replace imported cement mixing pile machines, reducing equipment investment costs and construction costs; specifically:

[0064] A. To address the problems and shortcomings of compaction grouting, the present invention uses blades to stir the soil and high-pressure jets to cut the soil, forming a uniform cement-soil mixture. This overcomes the shortcomings of compaction grouting, which are significantly affected by the properties of the strata and soil, and the slurry is easily lost and cannot form a vein-shaped composite foundation. A free-angle rotation device allows the drill to rotate 0 to 360 degrees, thereby forming cement-soil mixing piles or high-pressure rotary jet piles inside buildings, thereby improving the building's internal foundation and reducing damage to old buildings.

[0065] B. In response to the problems and shortcomings of deep mixing piles, the present invention adopts a free-angle rotation device to allow the drill to rotate 0-360 degrees, so that oblique and horizontal cement-soil mixing piles can be formed inside the building, thereby solving the problem of strengthening the foundation soil inside the building; adding a cement slurry nozzle above the mixing blade solves the problem that the conventional cement mixing pile spraying port is located below the bottom of the drill bit. When the slurry is lifted upward for spraying and mixing, the cement slurry is sprayed and accumulated below and cannot be stirred by the blades, which cannot achieve the effect of strengthening the soil and seriously wastes materials; through the redesign of the mixing pile drill bit, the drill bit has good effects in cutting and crushing the soil, thus solving the problems of common mixing drills easily getting stuck when mixing soil and difficulty in advancing. It replaces the imported IMS cement mixing pile machine and solves the problem of high cost;

[0066] C. To address the shortcomings and existing problems of high-pressure jet grouting piles, a vacuum mud suction pipeline is added inside the pipe to reduce soil, thereby solving the problem of ground uplift, which can damage buildings and cause danger. A soil static pressure sensor is added to the drill bit to sense changes in soil strength and provide timely feedback to the background automatic adjustment device, which can promptly adjust the high-pressure jet pressure and the mixing ratio of different media in the high-pressure jet flow, thereby reducing the unevenness of the pile body and the disadvantage of large discrete pile diameters.

[0067] (2) The free-angle soft soil foundation reinforcement construction equipment of the present invention adopts a flange structure to connect the hydraulic rotary power head with the free-angle rotary device and the adjacent drill rods, and is fixed with a pin. The connection operation is convenient and easy to disassemble quickly. In addition, a hydraulic telescopic drill rod is provided between the jet jet diverter and the adjacent extended drill rod or reinforced pile drilling tool, which solves the problem of long time to disassemble the drill rod and can reduce the risk of drill rod scrapping.

[0068] (3) The free-angle soft soil foundation reinforcement construction equipment of the present invention is provided with a guide ring fixed on the outer side of the reinforcement pile drill. The guide ring is coaxially arranged with the reinforcement pile drill, and the outer diameter of the guide ring is equivalent to the diameter of the circle formed by the mixing blade rotating around the drill axis. The guide ring can prevent the drill from sinking and deflecting during oblique drilling, thereby ensuring the drilling accuracy of the drill. In addition, a spiral rib consistent with the spiral direction of the mixing blade is provided on the outer wall of the guide ring, which improves the stability of the drilling or drilling guide.

[0069] (4) The free-angle soft soil foundation reinforcement construction equipment of the present invention has a pilot working part at the bottom of the spiral stirring alloy drill bit, and a hole expansion working part is provided on the stirring blades on the periphery of the spiral stirring alloy drill bit, which improves the soil cutting and crushing effect, and the drill bit drills efficiently and stably;

[0070] (5) The free-angle soft soil foundation reinforcement construction method of the present invention forms reinforcement piles that are cement mixing piles, high-pressure rotary jet piles, or composite piles with enlarged bodies. The pile type can be flexibly selected according to geological conditions and construction design requirements, greatly improving the bearing capacity of the reinforcement piles and construction flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 A schematic diagram of the construction of a protective building using the free-angle soft soil foundation reinforcement construction equipment and construction method of the present invention;

[0072] Figure 2 This is a schematic diagram of the structure of the reinforced pile drilling tool of the present invention;

[0073] Figure 3 A schematic structural diagram of a composite pile formed by the reinforced pile drilling tool of the present invention;

[0074] Figure 4Schematic diagram of the connection structure of the reinforcement pile drilling tool, the rotary jet diverter, and the hydraulic rotary power head in the present invention;

[0075] Figure 5 for Figure 4 A schematic diagram of the partially enlarged structure of the spiral stirring alloy drill bit;

[0076] Figure 6 for Figure 4 Schematic diagram of the connection structure between the mid-jet diverter and the hydraulic rotary power head.

[0077] Explanation of the numbers in the schematic diagram:

[0078] 1. Twister; 1-1. Boom; 1-2. Free-angle rotation device; 2. Hydraulic rotary power head; 2-1. Pin seat; 2-2. First connecting pin; 3. Jet splitter; 3-1. Inner shaft tube; 3-2. Outer sleeve; 3-3. First flange seat; 3-4. Second connecting pin; 3-5. Second flange seat; 4. Hydraulic telescopic drill pipe; 5. Extended drill pipe; 6. Reinforced pile drilling tool; 6-1. Spiral stirring alloy drill bit; 6-1-1. Pilot working part; 6-1-2. Hole expansion working part; 6-2. Mixing blade; 6-3. High-pressure cement slurry nozzle; 6-4. High pressure Cement slurry pipeline; 6-5, lower low-pressure cement slurry nozzle; 6-6, upper low-pressure cement slurry nozzle; 6-7, low-pressure cement slurry pipeline; 6-8, lower compressed air nozzle; 6-9, upper compressed air nozzle; 6-10, compressed air pipeline; 6-11, solenoid valve; 6-12, vacuum mud suction pipeline; 6-13, static pressure sensor; 6-14, signal line; 6-15, high-pressure water nozzle; 6-16, high-pressure water pipeline; 6-17, guide ring; 6-17a, spiral rib; 7, reinforcement pile; 7-1, cement mixing pile; 7-2, high-pressure rotary jet expansion body. DETAILED DESCRIPTION

[0079] In order to further understand the content of the present invention, the present invention is described in detail with reference to the accompanying drawings and embodiments.

[0080] [Example]

[0081] Combine Figures 1 to 6As shown, this embodiment of a free-angle soft soil foundation reinforcement construction equipment includes a screwdriver 1, a hydraulic rotary power head 2, a jet grouting diverter 3, and a reinforced pile drilling tool 6. The screwdriver 1 can be modified from an existing excavator. The screwdriver 1 has a boom 1-1 and a free-angle rotating device 1-2 mounted at the end of the boom 1-1. The boom 1-1, in conjunction with the free-angle rotating device 1-2, can freely change its angle from 0 to 360 degrees, allowing for freely changing the pile angle on soft soil foundations, thereby forming a reinforced pile body within the building to be protected. The free-angle rotating device 1-2 is connected to the hydraulic rotary power head 2, which can drive the drill tool to rotate forward and reverse, achieving rotary drilling or lifting. The hydraulic rotary power head 2 is connected to the reinforced pile drilling tool 6 via the jet grouting diverter 3 to achieve reinforced pile construction. Depending on the required designed pile depth, several extended drill rods 5 can be optionally provided between the jet grouting diverter 3 and the reinforced pile drilling tool 6. The jet splitter 3 is a multiple jet splitter. The extended drill rod 5 and the reinforced pile drill 6 both use multiple drill rods, which can input different high and low pressure jet streams to the pile bottom. Figures 2 to 5As shown, the bottom of the reinforcement pile drilling tool 6 is provided with a spiral stirring alloy drill bit 6-1 for cutting and crushing soil, and a plurality of stirring blades 6-2 are distributed along the axial interval on the outer wall of the reinforcement pile drilling tool 6, and the stirring blades 6-2 are distributed in a spiral shape for stirring and mixing soil and cement slurry; the stirring blades 6-2 located at the bottom of the reinforcement pile drilling tool 6 or on the spiral stirring alloy drill bit 6-1 are provided with a high-pressure cement slurry nozzle 6-3 and a high-pressure water nozzle 6-15 facing outward, the high-pressure cement slurry nozzle 6-3 is connected to the high-pressure cement slurry interface on the rotary jet diverter 3 through a high-pressure cement slurry pipeline 6-4, the high-pressure water nozzle 6-15 is connected to the high-pressure water interface on the rotary jet diverter 3 through a high-pressure water pipeline 6-16, the high-pressure cement slurry interface is used to connect an ultra-high pressure fluid pump, and ultra-high pressure grouting is formed by the high-pressure cement slurry nozzle 6-3 to crush and stir the soil, the high-pressure water interface is used to connect an ultra-high pressure water pump, and the high-pressure cement slurry is connected to the high-pressure water pump through the high-pressure cement slurry nozzle 6-3. The pressure water nozzle 6-15 sprays high-pressure water to cut and crush the soil; the reinforcement pile drilling tool 6 is provided with a lower low-pressure cement slurry nozzle 6-5 and a lower compressed air nozzle 6-8 below the mixing blade 6-2, and the reinforcement pile drilling tool 6 is provided with an upper low-pressure cement slurry nozzle 6-6 and an upper compressed air nozzle 6-9 above the mixing blade 6-2. The lower low-pressure cement slurry nozzle 6-5 and the upper low-pressure cement slurry nozzle 6-6 are connected to the low-pressure cement slurry interface on the rotary jet diverter 3 through a low-pressure cement slurry pipeline 6-7. The low-pressure cement slurry interface is used to connect a high-pressure fluid pump to spray cement slurry through the upper and lower low-pressure cement slurry nozzles; the lower compressed air nozzle 6-8 and the upper compressed air nozzle 6-9 are connected to the compressed air interface on the rotary jet diverter 3 through a compressed air pipeline 6-10. The compressed air interface is used to connect an air compressor to spray compressed air through the upper and lower compressed air nozzles. During the sinking or lifting process of the reinforcement pile drilling tool 6, cement slurry is sprayed while rotating and stirring, so that the cement slurry is fully mixed with the original foundation soil, thereby forming a cement mixing pile. In addition, the cement slurry nozzle added above the stirring blade 6-2 solves the problem that the conventional cement mixing pile grouting port is located below the bottom of the drill bit. When the cement slurry is sprayed and stirred upward, the cement slurry is sprayed and accumulated below, and cannot be stirred by the blades, thereby failing to achieve the effect of reinforcing the soil body and seriously wasting materials. In addition, during the sinking or lifting process of the reinforcement pile drilling tool 6, the high-pressure cement slurry nozzle 6-3 and the high-pressure water nozzle 6-15 can form an ultra-high pressure jet stream to cut and crush the soil body, thereby forming a high-pressure rotary jet pile.The spiral stirring alloy drill bit 6-1 is also equipped with a solenoid valve 6-11 and a static pressure sensor 6-13. The solenoid valve 6-11 is connected to the mud suction interface on the rotary jet diverter 3 via a vacuum mud suction pipeline 6-12. The mud suction interface is used to connect to the vacuum mud suction device. The static pressure sensor 6-13 is connected to the background control system via a signal line 6-14. The static pressure sensor 6-13 can monitor the changes in the slurry pressure and soil strength at the spiral stirring alloy drill bit 6-1. When the static pressure sensor 6-13 detects that the cement mixture pressure at the spiral stirring alloy drill bit 6-1 exceeds the set threshold, the background control system controls the solenoid valve 6-11 to open and suck out the excess cement mixture through the vacuum mud suction pipeline to prevent the ground from lifting and damaging the building. The above-mentioned solenoid valve 6-11 and static pressure sensor 6-13 can both be existing products, and the solenoid valve 6-11 and static pressure sensor 6-13 are integrated into the spiral stirring alloy drill bit 6-1.

[0082] By using the above-mentioned free-angle soft soil foundation reinforcement construction equipment, piles can be placed obliquely through the free-angle rotating device, and reinforced piles can be formed inside the building to improve the foundation strength inside the building. Cement mixing piles, high-pressure rotary jet piles, or high-pressure rotary jet plus mixed cement composite high-bearing composite piles can be formed according to geological conditions and construction design requirements; through the improvement of the reinforced pile drilling tool, the cement slurry and the original foundation soil can be fully mixed when the drilling tool sinks and rises, and the drilling tool has a better effect of cutting and crushing the soil, and is not prone to difficulty in advancing due to sticky drilling; and the static pressure sensor can be used to monitor the internal pressure, and the vacuum mud suction pipeline can be used to suck out the excess cement mixture, which solves the problem of ground lifting and thus damaging the building and causing danger; at the same time, it can replace imported cement mixing pile machines, reducing equipment investment costs and construction costs.

[0083] Reference Figure 4 and Figure 6As shown, a pin seat 2-1 for connecting the free angle rotating device 1-2 is provided at the upper end of the hydraulic rotary power head 2, and the hydraulic rotary power head 2 and the free angle rotating device 1-2 can be fixed by a connecting pin. The rotary jet diverter 3 includes an inner shaft tube 3-1 and an outer sleeve 3-2, which is rotatably and hermetically mounted on the inner shaft tube 3-1 and forms multiple independent fluid cavities between the inner shaft tube 3-1 and the outer sleeve 3-2. Each fluid cavity is sealed and separated by a sealing ring. The multiple fluid cavities include a compressed air cavity, a high-pressure water cavity, and high- and low-pressure mud cavities. The lower end of the hydraulic rotary power head 2 is axially inserted into the upper end of the inner shaft tube 3-1 and fixedly connected by a first connecting pin 2-2. The lower end of the inner shaft tube 3-1 is sleeved with a first flange seat 3-3, which is fixedly connected to the lower end of the inner shaft tube 3-1 by a second connecting pin 3-4. The lower end of the first flange seat 3-3 is also equipped with a second flange seat 3-5, which is used to flange-connect to an adjacent drill pipe or reinforced pile drilling tool 6. The above-mentioned connection structure makes the connection operation convenient and easy to disassemble quickly. In addition, as an optional solution, a hydraulic telescopic drill rod 4 is provided between the jet jet diverter 3 and the adjacent extended drill rod 5 or reinforced pile drilling tool 6, which solves the problem of long drill rod removal time and can reduce the risk of drill rod scrapping. The above-mentioned hydraulic telescopic drill rod 4 is prior art, and its working principle will not be described in detail here.

[0084] like Figure 4 As shown, in this embodiment, a guide ring 6-17 is fixedly provided on the outside of the reinforcement pile drilling tool 6. The guide ring 6-17 is coaxially arranged with the reinforcement pile drilling tool 6, and the outer diameter of the guide ring 6-17 is comparable to the diameter of the circle formed by the stirring blade 6-2 rotating around the drilling tool axis. The guide ring 6-17 is a circular ring structure, which is connected to the outer wall of the reinforcement pile drilling tool 6 by a connecting rod. The use of the guide ring 6-17 can prevent the drilling tool from sinking and deflecting during oblique drilling, thereby ensuring the drilling accuracy of the drilling tool. In addition, a spiral rib 6-17a is provided on the outer wall of the guide ring 6-17 in the same spiral direction as the stirring blade 6-2, which improves the stability of the drilling or drilling guide.

[0085] Further references Figure 5As shown, the bottom of the spiral stirring alloy drill bit 6-1 has a pilot working portion 6-1-1, and the stirring blades 6-2 on the periphery of the spiral stirring alloy drill bit 6-1 are provided with a reaming working portion 6-1-2. The drilling diameter of the pilot working portion 6-1-1 is smaller than the outer diameter of the reaming working portion 6-1-2. By redesigning the alloy drill bit of the reinforced pile drilling tool 6, the soil cutting and crushing effects are improved, and the drill bit drilling is efficient and stable. The high-pressure cement slurry nozzle 6-3 and the high-pressure water nozzle 6-15 can be installed on the stirring blades 6-2 on the periphery of the spiral stirring alloy drill bit 6-1. The lower low-pressure cement slurry nozzle 6-5 and the lower compressed air nozzle 6-8 can be installed on the spiral stirring alloy drill bit 6-1 or near the pilot working portion 6-1-1.

[0086] Reference Figures 1 to 3 As shown, this embodiment also discloses a free-angle soft soil foundation reinforcement construction method, comprising the following steps:

[0087] S1. Construction equipment assembly and preparation:

[0088] S1-1. Assemble the above-described free-angle soft soil foundation reinforcement construction equipment to form a complete set of main construction equipment for high-pressure rotary grouting and mixing cement composite high-load-bearing reinforcement piles. Specifically, the free-angle rotation device 1-2 can be installed on the auxiliary arm of the walking main equipment, followed by the hydraulic rotary power head 2, the rotary grouting diverter 3, the high-torque bidirectional multiple drill pipe joint, the high-pressure multiple drill pipe, and the spiral stirring alloy drill bit 6-1.

[0089] S1-2. Installation of backstage equipment: Install the air compressor, high-pressure fluid pump, ultra-high-pressure fluid pump, ultra-high-pressure water pump, cement mixing backstage and computer control backstage, and connect them with the above-mentioned main construction equipment through pipelines; after the walking main equipment is installed, move the above-mentioned main construction equipment to the pile position; during the positioning of the pile driver, an excavator can be used to lay the roadbed box or steel plate above the trench. The shift leader will command the pile driver to position. Before moving, check the situation from top to bottom, left to right, and remove any soft soil, silt or obstacles in a timely manner. After the pile driver is moved, carefully check the positioning and make corrections in a timely manner to ensure stability and levelness, thereby ensuring the safety of the pile driver and subsequent construction;

[0090] S1-3. Cement slurry is prepared on site through the cement mixing backend, and the cement slurry is mixed and transported. The cement mixing backend mainly consists of a 50-ton cement tank, an automatic conveying spiral feed pipe, an upper mixing barrel, a lower slurry storage barrel, a high-pressure fluid pump, an ultra-high-pressure fluid pump, and a computer control backend.

[0091] S1-4, start the free angle rotation device 1-2 through the hydraulic motor to adjust the angle of the reinforcement pile drilling tool 6;

[0092] S1-5. First, start the air compressor to perform a test air pressure injection to check whether the air pipeline is unobstructed; then start the high-pressure fluid pump and the ultra-high-pressure water pump to check whether the cement slurry pipeline and the water pipeline are unobstructed and whether the pressure meets the design requirements; then switch the high-pressure fluid pump to the ultra-high-pressure fluid pump and the ultra-high-pressure water pump, and recheck whether the cement slurry pipeline and the water pipeline are unobstructed and whether the pressure meets the ultra-high-pressure design requirements;

[0093] S2. Drilling and lifting of drilling tools:

[0094] S2-1. After confirming that all pipelines are unobstructed and the pressures have reached the design requirements, start the hydraulic rotary power head 2 for rotary drilling;

[0095] S2-2. According to the required depth of the design, during the whole process of drilling and lifting of the reinforced pile drilling tool 6, the drilling tool is kept rotating at a uniform speed, sinking and lifting at a uniform speed; and when the drilling tool is sinking and lifting, the mixed cement slurry is evenly and continuously injected through the high-pressure fluid pump, and the grouting pressure is controlled at 0.8MPa~1.0MPa to fully mix the cement slurry with the original foundation soil; when making high-pressure rotary jet piles, while rotating drilling, high-pressure water is sprayed by the ultra-high-pressure water pump to cut and crush the soil, and at the same time, the ultra-high-pressure fluid pump is started for ultra-high-pressure grouting to mix and stir with the crushed soil; the cement slurry is stirred by the BZ-20 environmentally friendly cement automatic mixing and grouting station, and is transported to the drill pipe head through the high-pressure fluid pump and cement pipe; specifically, during the sinking and lifting process of the drill pipe, according to the construction process and design requirements, the drill pipe needs to be injected with cement slurry when sinking and lifting, according to the construction process and design requirements. According to the parameters determined by the test pile, the cement slurry mixed must be injected uniformly and continuously during the construction process. When the drill rod is lifted, the designed cement slurry is completely injected and the mixing pile construction is completed. During the grouting and mixing process, the high-pressure fluid pump is started and the grouting pressure is controlled at 0.8MPa~1.0MPa. After the cement slurry arrives at the mixing head (spiral stirring alloy drill bit 6-1), the grouting is continuously stirred for more than 30 seconds. The mixing head is lifted at the speed required by calculation. Grouting, stirring and lifting are performed while the cement slurry and the original foundation soil are fully mixed. The bottom part of the mixing pile needs to be repeatedly stirred and grouting before lifting, and the grouting pump is closed again after being lifted to 50cm above the ground or the design elevation. In this step, the sinking and lifting speed of the reinforced pile drilling tool 6 are adapted to the pump capacity of the fluid pump. The control sinking spraying amount is 60% of the cement consumption, and the lifting spraying amount is 40% of the cement consumption. In this process, the drilling speed and the number of revolutions must also be controlled to ensure the quality of the pile.

[0096] S2-3. When making a composite pile with an enlarged head, the following steps are also included:

[0097] S2-3a, after the reinforced pile drilling tool 6 reaches the designed enlarged head position, the drilling speed and rotation speed are reduced, and at the same time, the pressure of the ultra-high pressure water pump is increased to 40Mpa~90Mpa, and the soil outside the mixing blade 6-2 is cut by high-pressure and high-speed water, and crushed and mixed. At the same time, the pressure of the ultra-high pressure fluid pump is also increased to 40Mpa~90Mpa, and the soil outside the mixing blade 6-2 is cut for the second time by high-pressure cement slurry, and crushed and mixed.

[0098] S2-3b. After reaching the bottom of the designed pile length, lift and jet grout the pile, increasing the lifting speed appropriately. Within the expanded range, repeatedly increase the pressure of the ultra-high-pressure water pump to 40 MPa to 70 MPa. Use high-pressure, high-speed water to cut the soil outside the mixing blade 6-2, crushing and mixing it. At the same time, increase the pressure of the ultra-high-pressure fluid pump to 40 MPa to 70 MPa, use high-pressure cement slurry to cut the soil outside the mixing blade for a second time, crushing and mixing it again, so that the diameter of the cement mixture reaches 1.5 m to 3 m.

[0099] S2-3b. Continue to elevate the reinforced pile drilling tool 6. When the elevation exceeds the range of the expansion body, appropriately reduce the pressure of the ultra-high pressure water pump and the pressure of the ultra-high pressure fluid pump, cooperate with the mixing blade 6-2 to cut, crush and stir the soil inside the mixing blade 6-2, and at the same time increase the rotation speed and lifting speed of the drilling tool;

[0100] S2-4. After reaching the designed pile top elevation, the drilling tool is lifted and the cement slurry in the reinforced pile drilling tool 6 is cleaned with clean water.

[0101] In addition, in step S2, the static pressure sensor 6-13 is turned on, and the change in soil strength is sensed by the static pressure sensor 6-13, and transmitted to the background control system through the signal line 6-14, and the background control system adjusts the pressure of the high-pressure jet flow and the mixing ratio of the high-pressure jet flow; after the static pressure sensor 6-13 detects that the pressure of the cement mixture at the spiral stirring alloy drill bit 6-1 exceeds the set threshold, the background control system controls the solenoid valve 6-11 to open, and the excess cement mixture is sucked out through the vacuum mud suction pipeline, thereby solving the problem of causing ground lifting and thus damaging buildings and causing danger.

[0102] Reference Figure 3 As shown, this embodiment also relates to a free-angle soft soil foundation reinforcement pile, which is formed by the above-mentioned free-angle soft soil foundation reinforcement construction method. The formed reinforcement pile 7 is a cement mixing pile or a high-pressure rotary jet pile or a composite pile with an enlarged body. Specifically, it can be a cement mixing pile, a high-pressure rotary jet pile, or a composite pile such as Figure 3The composite pile shown is composed of a cement mixing pile 7-1 and a high-pressure rotary jet expansion body 7-2 located at the bottom of the cement mixing pile 7-1. The pile type can be flexibly selected according to geological conditions and construction design requirements, which greatly improves the bearing capacity and construction flexibility of the reinforced pile.

[0103] The free-angle soft soil foundation reinforcement construction equipment, construction method and reinforcement piles of the present invention have the following beneficial effects:

[0104] A. To address the problems and shortcomings of compaction grouting, the present invention uses blades to stir the soil and high-pressure jets to cut the soil, forming a uniform cement-soil mixture. This overcomes the shortcomings of compaction grouting, which are significantly affected by the properties of the strata and soil, and the slurry is easily lost and cannot form a vein-shaped composite foundation. A free-angle rotation device allows the drill to rotate 0 to 360 degrees, thereby forming cement-soil mixing piles or high-pressure rotary jet piles inside buildings, thereby improving the building's internal foundation and reducing damage to old buildings.

[0105] B. In response to the problems and shortcomings of deep mixing piles, the present invention adopts a free-angle rotation device to allow the drill to rotate 0-360 degrees, so that oblique and horizontal cement-soil mixing piles can be formed inside the building, thereby solving the problem of strengthening the foundation soil inside the building; adding a cement slurry nozzle above the mixing blade solves the problem that the conventional cement mixing pile spraying port is located below the bottom of the drill bit. When the slurry is lifted upward for spraying and mixing, the cement slurry is sprayed and accumulated below and cannot be stirred by the blades, which cannot achieve the effect of strengthening the soil and seriously wastes materials; through the redesign of the mixing pile drill bit, the drill bit has good effects in cutting and crushing the soil, thus solving the problems of common mixing drills easily getting stuck when mixing soil and difficulty in advancing. It replaces the imported IMS cement mixing pile machine and solves the problem of high cost;

[0106] C. In view of the shortcomings and existing problems of high-pressure rotary jet grouting piles, a vacuum mud suction pipeline is added inside the pipe to reduce soil, thereby solving the problem of ground uplift, which damages buildings and causes danger. A soil static pressure sensor is added to the drill bit to sense the changes in soil strength, and timely feedback is given to the background automatic adjustment device to timely adjust the high-pressure jet flow pressure and the mixing ratio of different media in the high-pressure jet flow, thereby reducing the unevenness of the pile body and the disadvantage of large discrete pile diameters.

[0107] In addition, by adding a soil static pressure sensor to the drill bit to sense the changes in soil strength, timely feedback is given to the background automatic adjustment device, and the high-pressure jet pressure and the mixing ratio of different media in the high-pressure jet are adjusted in time to reduce the unevenness of the pile body and the disadvantage of large discrete pile diameters; the problem of disassembling the drill rod is solved by adopting a telescopic drill rod device, which greatly reduces labor costs and the problem that high-pressure rotary jet piles cannot be constructed in the case of a two-component coagulant (such as water glass and cement slurry) medium.

[0108] The above is a schematic description of the present invention and its embodiments, 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 this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without creatively designing them, they shall fall within the scope of protection of the present invention.

Claims

1. A free-angle soft soil foundation reinforcement construction equipment, comprising a screwing machine (1), a hydraulic rotary power head (2), a rotary jet diverter (3) and a reinforced pile drilling tool (6), wherein the screwing machine (1) has a boom (1-1) and a free-angle rotating device (1-2) installed at the end of the boom (1-1), the free-angle rotating device (1-2) is connected to the hydraulic rotary power head (2), the hydraulic rotary power head (2) is connected to the reinforced pile drilling tool (6) through the rotary jet diverter (3), and a plurality of extended drill rods (5) are selectively provided between the rotary jet diverter (3) and the reinforced pile drilling tool (6); the characteristics are: The bottom of the reinforced pile drilling tool (6) is provided with a spiral stirring alloy drill bit (6-1), and a plurality of stirring blades (6-2) are distributed axially at intervals on the outer wall of the reinforced pile drilling tool (6). The stirring blade (6-2) located at the bottom of the reinforced pile drilling tool (6) or on the spiral stirring alloy drill bit (6-1) is provided with a high-pressure cement slurry nozzle (6-3) and a high-pressure water nozzle (6-15) facing outwards. The high-pressure cement slurry nozzle (6-3) is connected to the high-pressure cement slurry interface on the rotary jet diverter (3) through a high-pressure cement slurry pipeline (6-4), and the high-pressure water nozzle (6-15) is connected to the high-pressure water interface on the rotary jet diverter (3) through a high-pressure water pipeline (6-16). The reinforced pile drilling tool (6) is provided with a lower low-pressure cement slurry nozzle (6-5) and a lower compressed air nozzle (6-8) below the stirring blade (6-2). An upper low-pressure cement slurry nozzle (6-6) and an upper compressed air nozzle (6-9) are respectively provided above the stirring blade (6-2); the lower low-pressure cement slurry nozzle (6-5) and the upper low-pressure cement slurry nozzle (6-6) are connected to the low-pressure cement slurry interface on the rotary jet diverter (3) through a low-pressure cement slurry pipeline (6-7); the lower compressed air nozzle (6-8) and the upper compressed air nozzle (6-9) are connected to the compressed air interface on the rotary jet diverter (3) through a compressed air pipeline (6-10); and the spiral stirring alloy drill bit (6-1) is also provided with a solenoid valve (6-11) and a static pressure sensor (6-13); the solenoid valve (6-11) is connected to the mud suction interface on the rotary jet diverter (3) through a vacuum mud suction pipeline (6-12), and the static pressure sensor (6-13) is connected to a background control system through a signal line (6-14).

2. The free-angle soft soil foundation reinforcement construction equipment according to claim 1, characterized in that: The upper end of the hydraulic rotary power head (2) is provided with a latch seat (2-1) for connecting to the free angle rotation device (1-2); the rotary jet diverter (3) comprises an inner shaft tube (3-1) and an outer sleeve (3-2); the outer sleeve (3-2) is rotatably and sealingly sleeved on the inner shaft tube (3-1) and forms multiple independent fluid cavities between the inner shaft tube (3-1) and the outer sleeve (3-2); the lower end of the hydraulic rotary power head (2) is axially inserted into the upper end of the inner shaft tube (3-1) and fixedly connected via a first connecting pin (2-2); the lower end of the inner shaft tube (3-1) is sleeved with a first flange seat (3-3); the first flange seat (3-3) and the lower end of the inner shaft tube (3-1) are fixedly connected via a second connecting pin (3-4); and the lower end of the first flange seat (3-3) is also provided with a second flange seat (3-5).

3. The free-angle soft soil foundation reinforcement construction equipment according to claim 1, characterized in that: A hydraulic telescopic drill rod (4) is further provided between the jet-jet diverter (3) and the adjacent extended drill rod (5) or reinforced pile drilling tool (6).

4. The free-angle soft soil foundation reinforcement construction equipment according to claim 1, characterized in that: A guide ring (6-17) is also fixedly provided on the outer side of the reinforcement pile drilling tool (6), and the guide ring (6-17) is coaxially arranged with the reinforcement pile drilling tool (6).

5. The free-angle soft soil foundation reinforcement construction equipment according to claim 4, characterized in that: The outer side wall of the guide ring (6-17) is further provided with a spiral rib (6-17a) that is consistent with the spiral direction of the stirring blade (6-2).

6. The free-angle soft soil foundation reinforcement construction equipment according to claim 4, characterized in that: The bottom of the spiral stirring alloy drill bit (6-1) is provided with a pilot working portion (6-1-1), and the stirring blade (6-2) on the periphery of the spiral stirring alloy drill bit (6-1) is provided with a hole expansion working portion (6-1-2).

7. A free-angle soft soil foundation reinforcement construction method, characterized in that: The steps include: S1. Construction equipment assembly and preparation: S1-1. Assemble the free-angle soft soil foundation reinforcement construction equipment according to any one of claims 1 to 6 to form a complete set of main construction equipment for high-pressure rotary grouting and mixing cement composite high-load reinforcement piles; S1-2. Install an air compressor, a high-pressure fluid pump, an ultra-high-pressure fluid pump, an ultra-high-pressure water pump, a cement mixing backstage, and a computer control backstage, and connect them to the main construction equipment through pipelines; then move the main construction equipment to the pile position; S1-3, prepare cement slurry on site through cement mixing background, and mix and transport cement slurry; S1-4, starting the free angle rotation device (1-2) through the hydraulic motor to adjust the angle of the reinforcement pile drilling tool (6); S1-5. First, start the air compressor to perform a test air pressure injection to check whether the air pipeline is unobstructed; then start the high-pressure fluid pump and the ultra-high-pressure water pump to check whether the cement slurry pipeline and the water pipeline are unobstructed and whether the pressure meets the design requirements; then switch the high-pressure fluid pump to the ultra-high-pressure fluid pump and the ultra-high-pressure water pump, and recheck whether the cement slurry pipeline and the water pipeline are unobstructed and whether the pressure meets the ultra-high-pressure design requirements; S2. Drilling and lifting of drilling tools: S2-1. After confirming that all pipelines are unobstructed and the pressures have reached the design requirements, start the hydraulic rotary power head (2) to perform rotary drilling; S2-2. According to the design depth, during the entire process of drilling and lifting the reinforcement pile drilling tool (6), the drilling tool is kept rotating at a constant speed, sinking and lifting at a constant speed; When the drill tool is lowered and lifted, the mixed cement slurry is evenly and continuously injected through the high-pressure fluid pump. The grouting pressure is controlled at 0.8MPa~1.0MPa to fully mix the cement slurry with the original foundation soil. When making high-pressure jet grouting piles, while rotating the drill, the ultra-high-pressure water pump is used to spray high-pressure water to cut and crush the soil. At the same time, the ultra-high-pressure fluid pump is started to perform ultra-high-pressure grouting to mix and stir with the crushed soil. S2-3. When making a composite pile with an enlarged head, the following steps are also included: S2-3a, after the reinforced pile drilling tool (6) reaches the designed enlarged head position, the drilling speed and rotation speed are reduced, and at the same time, the pressure of the ultra-high pressure water pump is increased to 40Mpa~90Mpa, and the soil outside the mixing blade (6-2) is cut by high-pressure and high-speed water, and crushed and mixed. At the same time, the pressure of the ultra-high pressure fluid pump is increased to 40Mpa~90Mpa, and the soil outside the mixing blade (6-2) is cut for the second time by high-pressure cement slurry, and crushed and mixed. S2-3b. After reaching the bottom of the designed pile length, the lifting and jetting are carried out, and the lifting speed is appropriately increased. Within the expansion range, the pressure of the ultra-high pressure water pump is repeatedly increased to 40Mpa~70Mpa. The high-pressure and high-speed water is used to cut the soil outside the mixing blade (6-2) and crush and mix it. At the same time, the pressure of the ultra-high pressure fluid pump is also increased to 40Mpa~70Mpa. The high-pressure cement slurry is used to cut the soil outside the mixing blade for a second time, and crush and mix it again, so that the diameter of the cement mixture reaches 1.5m~3m. S2-3c, continue to elevate the reinforced pile drilling tool (6), and when the elevation exceeds the range of the expansion body, appropriately reduce the pressure of the ultra-high pressure water pump and the pressure of the ultra-high pressure fluid pump, cooperate with the mixing blade (6-2) to cut, crush and stir the soil in the mixing blade (6-2), and at the same time increase the rotation speed and lifting speed of the drilling tool; S2-4. After reaching the designed pile top elevation, the drilling tool is lifted and the cement slurry in the reinforced pile drilling tool (6) is cleaned with clean water.

8. The free-angle soft soil foundation reinforcement construction method according to claim 7, characterized in that: In step S2, the static pressure sensor (6-13) is turned on, and the change in soil strength is sensed by the static pressure sensor (6-13), and transmitted to the background control system through the signal line (6-14), and the background control system adjusts the pressure of the high-pressure jet flow and the mixing ratio of the high-pressure jet flow; after the static pressure sensor (6-13) detects that the pressure of the cement mixture at the spiral stirring alloy drill bit (6-1) exceeds the set threshold, the background control system controls the solenoid valve (6-11) to open, and the excess cement mixture is sucked out through the vacuum mud suction pipeline.

9. The free-angle soft soil foundation reinforcement construction method according to claim 7 or 8, characterized in that: In step S2, the sinking and lifting speeds of the reinforcement pile drilling tool (6) are adapted to the pumping capacity of the fluid pump, and the sinking spraying capacity is controlled to be 60% of the cement usage, and the lifting spraying capacity is controlled to be 40% of the cement usage.

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