Super-hectometer vibroflotation mixing pile and jet grouting pile equipment and construction technology

Abstract

The invention relates to more than 100-meter vibroflotation mixing pile and jet grouting pile equipment and a construction process, in particular to construction of a 150-meter vibroflotation mixing pile and jet grouting pile, and belongs to the field of foundation treatment. The equipment comprises a power frame, a rotary hanging head, a follow-up frame, a telescopic guide rod, a power head, a grouting system, a vibroflot and a winch. According to the invention, efficient crushing, uniform mixing and accurate guniting of a gravel-cobble layer can be realized; through a 30-meter power frame and a sliding rod type / self-locking rod type telescopic guide rod, pile forming at the depth of more than one hundred meters is achieved, and a mast pile frame with the height of one hundred meters is not needed; the vibroflot is adopted for transverse vibration reaming, the problems that a gravel-cobble layer is not thorough in penetrating, uneven in mixing and collapsed in hole wall are solved, and it is guaranteed that the pile body is uniform in strength and stable in bearing capacity; the pile frame height is reduced, and the construction safety is improved; and a vibroflotation compaction process is combined, a guniting mode is optimized, slurry loss is reduced, and the construction cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of foundation treatment technology, specifically to the construction of vibratory mixing piles and jet grouting piles exceeding 100 meters by combining the principle of vibratory compaction construction, and particularly the construction of vibratory mixing piles and jet grouting piles exceeding 150 meters. Background Technology

[0002] Existing traditional mixing piles and jet grouting piles have fundamental technical defects in construction on gravel layers up to 100 meters deep, and cannot meet the needs of ultra-deep foundation reinforcement. The technical problems are as follows:

[0003] The core defects of traditional mixing piles are: relying on a fixed-length mixing shaft and external mixing blades, which are limited by the height of the pile frame (construction depth ≤ pile frame height), and cannot break through 100 meters in depth; the mixing coverage of the blades is limited, and when faced with pebbles and gravels with high hardness (Mohs hardness 6-8) and uneven particle size (5-300mm), the drill is easily stuck and broken, and large pebbles and gravels cannot be effectively crushed and mixed, resulting in uneven pile strength and insufficient bearing capacity.

[0004] The core defects of traditional jet grouting piles are: cutting the strata by high-pressure jetting grout, but the high porosity of the gravel layer at a depth of 100 meters makes it easy for the high-pressure grout to be lost along the pores, resulting in wasted grout volume and poor pile formation; the jetting flow has weak crushing ability on gravel, the grout mixes poorly with soil particles, and the pile has insufficient shear strength.

[0005] High drilling resistance: Gravel particles are hard and unevenly graded, making it difficult for traditional drilling tools to penetrate efficiently, which can easily lead to drill pipe bending and stuck drill accidents.

[0006] Poor borehole stability: The gravel layer at a depth of 100 meters lacks cohesive soil cementation, making it prone to collapse after drilling and unable to maintain the pile foundation channel;

[0007] Poor equipment adaptability: Traditional mixing piles and jet grouting piles require the use of pile frames with masts over 100 meters high, resulting in extremely poor safety and stability, and high construction costs;

[0008] Low grout utilization rate: High-pressure jet grouting in rotary grouting piles results in high grout loss rate, while the grout diffusion range in mixing piles is limited, neither of which can achieve precise mixing of grout with soil and rock. Summary of the Invention

[0009] Based on the above technical problems, the purpose of this invention is to use vibratory compaction technology, with "ultra-deep penetration, vibration compaction, rotary mixing, and precise grouting" as the core, to replace the blade mixing mechanism of traditional mixing piles and the high-pressure jetting mechanism of rotary grouting piles. Through a 30-meter low-headroom pile frame or a combination of rotary drilling rig and telescopic guide rod, it can achieve efficient pile formation in 100-meter gravel layers, solving the problems of limited depth, uneven mixing, significant safety hazards, and grout waste in traditional processes.

[0010] In foundation treatment engineering, mixing piles are based on "mechanical mixing + slurry mixing", while jet grouting piles are based on "high-pressure jetting + slurry diffusion". Both are conventional foundation reinforcement technologies, but they both have insurmountable defects in ultra-deep (≥100m) gravel layers:

[0011] Mixing piles: The construction depth depends entirely on the height of the pile frame mast. The maximum construction depth of existing equipment on the market is ≤60m (corresponding to a pile frame height ≥60m). Moreover, tall mast pile frames are easily affected by wind and site limitations, posing extremely high safety risks. The blade mixer has weak crushing ability for pebbles and gravel, poor mixing uniformity, and the pile strength cannot meet the design requirements.

[0012] Jet grouting piles: At depths of 100 meters, the high-pressure grout (typically ≥20MPa) easily flows through the pores of gravel, resulting in a grout loss rate of 30%-50%. This leads to irregular pile diameters, inability to break large-diameter gravel, internal voids within the pile body, and significant fluctuations in bearing capacity. Currently, mixing pile construction uses tall masts, with the construction depth being less than the mast's height. There is currently no equipment on the market that allows mixing pile construction to a depth greater than the mast's height.

[0013] Currently, there is no equipment on the market that simultaneously possesses the functions of "ultra-deep penetration, vibration compaction, rotary mixing, and precision spraying". The closest technical solution is:

[0014] Traditional mixing pile equipment: uses a tall mast pile frame + fixed mixing shaft + mixing blades, the construction depth is less than or equal to the height of the pile frame, and the blade mixing cannot be adapted to gravel layers;

[0015] Traditional jet grouting equipment uses a high-pressure grouting pump and jetting rod, which cuts through the strata with high-pressure grout, resulting in uneven grout diffusion and severe grout loss in ultra-deep construction.

[0016] None of the above solutions solved the integrated problem of "penetration, compaction, mixing, and spraying in a 100-meter-long gravel layer".

[0017] The specific technical solution of the present invention is as follows:

[0018] Firstly, the equipment for vibratory compaction and jet grouting piles exceeding 100 meters in length includes a power frame, rotating crane, follower frame, telescopic guide rod, power head, grouting system, vibratory compactor, and winch.

[0019] The telescopic guide rod is installed directly in front of the power frame. The upper section of the telescopic guide rod is connected to the rotating head and the power head, and the lower end of the telescopic guide rod is connected to the vibratory impactor. The power head is used to drive the vibratory impactor to rotate.

[0020] The grouting system includes a cement silo, a mud pump, a cement grout pipe, a cement grout channel located inside the telescopic guide rod, and a grouting pipe located at the vibratory compactor water channel. The mud pump is connected to the cement silo, one end of the cement grout pipe is connected to the mud pump, the other end of the cement grout pipe is connected to the cement grout channel, and the cement grout channel is connected to the grouting pipe.

[0021] The top of the power frame is equipped with a hanging anchor frame, and the wire rope of the winch is connected to the rotating head through the hanging anchor frame;

[0022] The power frame is one of the following: mast-type pile frame, rotary drilling rig, or excavator body.

[0023] The upper section of the telescopic guide rod is slidably connected to the power frame via a follower frame.

[0024] Furthermore, the vibratory impactor is equipped with spiral crushing and stirring teeth on its exterior.

[0025] Furthermore, the grouting system also includes a rotary grout adapter valve, which is installed between the cement grout pipe and the cement grout channel.

[0026] Furthermore, a guide rod locking key is provided on the outer wall of the telescopic guide rod.

[0027] Secondly, the construction process of the ultra-100-meter vibratory compaction and jet grouting pile equipment includes the following steps:

[0028] The vibratory punching hole-making stage is divided into the first hole-making stage, the second hole-making stage, and the third hole-making stage. In the first hole-making stage, the vibratory punch is started and rotates synchronously.

[0029] During the second drilling stage, the telescopic guide rod extends, the vibratory compactor is activated, and the vibratory compactor rotates synchronously.

[0030] In the third drilling stage, the telescopic guide rod extends, the vibratory compactor is activated, and the vibratory compactor rotates synchronously.

[0031] Furthermore, in the first hole-making stage, the vibration frequency of the vibratory punch is 25-30Hz, the rotation speed is 10-12r / min, and the hole-making depth does not exceed 40m;

[0032] In the second drilling stage, the telescopic guide rod is extended, the vibratory compactor is started, the vibratory compactor rotates synchronously, the vibration frequency of the vibratory compactor is 30-35Hz, and the drilling depth does not exceed 80m.

[0033] In the third drilling stage, the telescopic guide rod is extended, the vibratory compactor is started, the vibratory compactor rotates synchronously, the vibration frequency of the vibratory compactor is 35-40Hz, and the drilling depth does not exceed 100m;

[0034] Furthermore, if the borehole wall collapses during the drilling process, stone is added during drilling until the designed depth is reached. At this point, the vibratory compactor is paused, and the grouting system is activated for low-pressure grouting. The grouting pressure is 5-8 MPa, and the grouting volume is 0.2-0.3 m per meter of pile length. 3 Grouting is then carried out.

[0035] Furthermore, in the densification stage, crushed stone is filled in layers and compacted by vibratory compaction and grouting, with the vibratory compactor rotating synchronously;

[0036] If the geological conditions consist of a layer of fine gravel with a particle size of 5-50mm, the construction parameters are as follows: vibratory compactor frequency 25-30Hz, vibratory compactor rotation speed 8-10r / min, grouting pressure 12-15MPa, and grouting volume 0.6-0.7m. 3 / m;

[0037] If the geological conditions consist of medium-sized gravel and pebbles with a particle size of 50-100mm, the construction parameters are as follows: vibratory compactor frequency 30-35Hz, vibratory compactor rotation speed 7-8r / min, grouting pressure 15-17MPa, and grouting volume 0.7-0.8m. 3 / m;

[0038] If the geological conditions consist of a coarse gravel layer with a particle size of 100-300mm, the construction parameters are as follows: vibratory compactor frequency 35-40Hz, vibratory compactor rotation speed 5-7r / min, grouting pressure 17-18MPa, and grouting volume 0.8-0.9m. 3 / m.

[0039] Furthermore, the entire grouting process is monitored in real time by the equipped recorder to detect the amount of grout injected into the hole and to trigger alarms for grout loss.

[0040] Furthermore, when constructing in gravel layers, during the drilling stage, the vibration frequency of the vibratory compactor is positively correlated with the drilling depth. Meanwhile, during the drilling process at depths of 0-70m, the rotational speed of the vibratory compactor remains constant; however, for drilling depths above 70m, the drilling depth and the rotational speed of the vibratory compactor are negatively correlated.

[0041] During the densification phase, the vibration frequency of the vibratory compactor changes positively with the construction depth. Meanwhile, during the densification process with a depth of 0 to 70 m, the rotation speed of the vibratory compactor remains constant; when the densification depth is above 70 m, the rotation speed of the vibratory compactor decreases and remains constant.

[0042] Furthermore, when constructing on gravel layers, if geological obstacles containing carbonate rock fragments or quartzite / granite fragments are encountered during construction, the vibration frequency of the vibratory compactor is increased and the rotation speed of the vibratory compactor is reduced.

[0043] The core shortcomings of existing technologies

[0044] Depth limitations: The construction depth of mixing piles is less than or equal to the height of the pile frame, and the ultra-deep construction effect of jet grouting piles is poor. Neither can meet the requirements for pile formation in 100-meter gravel layers.

[0045] Low mixing efficiency: The mixing and coverage of the mixing pile blades is limited, and the grout diffusion of the jet grouting pile is uneven, neither of which can achieve sufficient mixing of gravel and hardener;

[0046] Poor equipment safety: The mixing pile requires a 100-meter-high mast pile frame, which is not stable enough and is prone to overturning accidents;

[0047] Significant grout waste: High-pressure jet grouting in rotary grouting piles leads to a high grout loss rate;

[0048] Weak penetration ability: Neither mixing piles nor jet grouting piles can efficiently penetrate large-diameter gravel, and the pile body has weak points in strength.

[0049] Compared with the prior art, the beneficial effects of the present invention are:

[0050] Process substitution: The integrated vibratory compaction and rotary grouting technology replaces the blade mixing process of traditional mixing piles and the high-pressure jetting process of jet grouting piles, achieving efficient crushing, uniform mixing, and precise grouting of gravel layers.

[0051] Breakthrough in depth: By using a 30-meter mast-type pile frame or a rotary drilling rig with a sliding rod / self-locking rod telescopic guide rod, piles can be driven to depths of over 100 meters without the need for a 100-meter-high mast-type pile frame; it is especially suitable for piles driven to depths of 150 meters, breaking through the limitations of existing technologies.

[0052] Quality improvement: Solve the problems of incomplete penetration of gravel layer, uneven mixing, and hole wall collapse, and ensure uniform pile strength and stable bearing capacity.

[0053] Safety and energy saving: Reduce the height of the pile frame to improve construction safety; optimize the shotcrete method to reduce grout loss and lower construction costs. Attached Figure Description

[0054] Figure 1 This is a side view of the ultra-100-meter vibratory compaction and jet grouting equipment described in this invention.

[0055] Figure 2 This is a schematic diagram of the front view of the ultra-100-meter vibratory mixing pile and jet grouting pile equipment described in this invention;

[0056] Figure 3 This is a schematic diagram of the construction of the ultra-100-meter vibratory mixing pile and jet grouting pile equipment described in this invention at a depth of 100 meters. Detailed Implementation

[0057] The present invention will be described in detail below with reference to specific embodiments. These embodiments are merely some, not all, implementations of the present invention. All other implementations obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0058] Example 1

[0059] like Figures 1-2 As shown, the ultra-100-meter vibratory compaction and jet grouting pile equipment of the present invention includes a 30-meter power frame (preferably a mast-type pile frame or a rotary drilling rig), a rotating head, a follower frame, a telescopic guide rod (sliding rod type / self-locking rod type), a power head, a shock absorber, a grouting system, a vibratory compactor, and two coils, one of which is a water pipe / electrical cable coil, and the other is a cement grout pipe coil. The telescopic guide rod is installed directly in front of the mast-type pile frame or rotary drilling rig. The upper section of the telescopic guide rod connects the rotating head and the power head, and the lower end of the telescopic guide rod connects to the vibratory compactor. The grouting system includes a mud pump, a cement grout pipe, a cement grout channel located within the telescopic guide rod, and a grouting pipe located at the water channel of the vibratory compactor (existing vibratory compactors generally have their own water channel). One end of the cement grout pipe is connected to the mud pump, and the other end is connected to the cement grout channel, which is connected to the grouting pipe. The mud pump injects cement slurry through cement slurry pipes, cement slurry channels, and grouting pipes, enabling continuous grouting while rotating; the shock absorber is installed between the power head and the telescopic guide rod to counteract the impact of vibratory impact on the mast-type pile frame or rotary drilling rig.

[0060] 1. This invention adopts an integrated vibratory compaction and rotation device (core component) as the core component to replace the mixing blades and the jet grouting nozzle, integrating excitation, 360° rotation, and precise grouting functions; the excitation is provided by the vibratory compactor, with a vibration frequency of 10-50Hz and an amplitude of 5-15mm, providing strong vibration force to break up pebbles and gravel; the power head drives the telescopic guide rod to rotate the vibratory compactor at a rotation speed of 5-15r / min (steplessly adjustable), driving the entire vibratory compactor to rotate, replacing the mixing function of traditional mixing blades; the central channel is a cement slurry channel (diameter 50-80mm); the cement slurry is directly injected into the mixing zone with the rotation (replacing the high-pressure jet grouting nozzle of the jet grouting pile), avoiding slurry loss.

[0061] In some other embodiments, spiral crushing and agitating teeth may be installed on the outside of the vibratory impactor.

[0062] In some other embodiments, if the vibratory compactor is a hydraulic vibratory compactor, the telescopic guide rod can have a built-in dual channel: the outer side can be designed as an annular channel as needed, serving as a hydraulic oil passage.

[0063] 2. Sliding rod / self-locking rod telescopic guide rod (depth-adaptive component) replaces the fixed drill rod / mixing shaft of traditional mixing piles and jet grouting piles, enabling 30-meter mast-type pile frames or rotary drilling rigs to adapt to depths of up to 100 meters. Figure 3 As shown; the structural type can be either a sliding rod type telescopic rod (which is hydraulically driven to extend and retract) or a self-locking rod type telescopic rod (which is fixed by a mechanical self-locking mechanism to fix the telescopic section), and adopts a three-section design (outer rod, middle rod, inner rod); the built-in cement slurry channel and hydraulic oil channel supply slurry to the vibratory compactor and oil to the power head, respectively; the outer wall is equipped with a guide rod locking key to enhance the stability of the hole wall during rotation and prevent collapse.

[0064] In some other embodiments, if the construction depth needs to reach 150 meters underground, the power frame (mast-type pile frame or rotary drilling rig) is still 30 meters high, but the telescopic guide rod needs to adopt a five-section design (such as the first rod, the second rod, the third rod, the fourth rod, and the fifth rod), so as to meet the construction requirements on the 30-meter-high power frame foundation.

[0065] 3. The grouting system replaces the high-pressure grouting system of the jet grouting pile, achieving stable and precise grouting under rotation. The grouting system also includes a cement silo, a rotating grout adapter valve, and a pressure sensor (range 0-20MPa). The rotating grout adapter valve is installed between the cement grout pipe and the cement grout channel. The rotating grout adapter valve has a rotating sealing structure, which can maintain the seal between the cement grout pipe and the cement grout channel when the vibratory compactor rotates 360°, with a pressure loss ≤0.5MPa. The dynamic adjustment range of the grouting pressure is 5-18MPa, precisely matched with the rotation speed (pressure 12-18MPa at a speed of 5-10r / min to ensure that the grout penetrates the gaps between pebbles and gravel; pressure 5-10MPa at a speed of 10-15r / min to ensure that the grout is uniformly mixed).

[0066] The top of the mast-type pile frame or rotary drilling rig is equipped with a hoisting anchor frame. The wire rope of the winch is connected to the rotating head through the hoisting anchor frame. The function of the rotating head is to keep the wire rope stationary when the telescopic guide rod rotates 360°.

[0067] The upper section (or inner rod) of the telescopic guide rod is slidably connected to the mast-type pile frame or rotary drilling rig by installing a follower frame.

[0068] Ultimately, it achieves coordinated control of vibration, rotation, grouting, and expansion, replacing the independent control mode of traditional mixing piles and jet grouting piles.

[0069] Example 2

[0070] The construction process is as follows:

[0071] 1. Vibro-compaction drilling stage (breaking through a hundred-meter-deep gravel layer to form a stable pile hole)

[0072] This stage follows the "vibration drilling" logic of vibratory stone piles, and innovatively incorporates "360° rotation + telescopic guide rod segmented drilling + grouting":

[0073] Hole-making stage: Start the vibratory compactor (frequency 25-30Hz, amplitude 10-12mm) + rotating unit (speed 10-12r / min), and slowly lower the outer rod of the telescopic guide rod using a winch (lowering speed 0.2-0.3m / min); the vibratory compactor vibrates to loosen the gravel particles, and the rotating unit cuts coarse gravel (particle size >100mm, crushed to ≤50mm). The guide rod lock key on the outer wall of the telescopic guide rod assists in guiding and prevents the hole wall from collapsing; suspend hole-making when the hole reaches 30-40m (the limit depth of the outer rod);

[0074] Segmented telescopic drilling: Unlock the telescopic guide rod locking mechanism, extend the middle rod (30-40m), insert the locking pin and re-measure the coaxiality (error ≤0.5mm); adjust the vibratory parameters (frequency 30-35Hz, amplitude 12-15mm, to cope with greater resistance at deeper layers), and continue rotating the drilling to 60-80m; similarly, extend the inner rod (20-30m), adjust the frequency to 35-40Hz, and finally drill the hole to the designed pile depth of 100m;

[0075] Borehole stability control: If borehole wall collapse occurs during drilling (manifested as a sudden decrease in grout return), suspend lowering, start the grouting system (low-pressure grouting, pressure 5-8 MPa), and inject a small amount of cement grout (0.2-0.3 m per meter of pile length). 3 After forming a temporary protective wall, continue drilling.

[0076] Technical objective: To efficiently penetrate gravel and pebbles through "vibration + rotation", and to overcome the 100-meter depth limit with segmented telescopic guide rods, thus solving the problem of "fixed guide rod drilling depth ≤30m and drill getting stuck in coarse gravel" in traditional vibratory stone crushing piles; temporary low-pressure grouting ensures the stability of the hole wall and avoids the collapse of the hole wall during subsequent stone filling.

[0077] 2. Layered crushed stone filling stage (providing skeletal support for densified grouting)

[0078] This stage requires controlling the amount of fill stone and the thickness of loose fill to lay the foundation for subsequent cement grout penetration and bonding.

[0079] Crushed stone preparation: Select graded crushed stone (particle size 20-80mm, mud content ≤3%), and pile it around the pile hole in advance (1.5m from the pile center, pile height 1.2m). The theoretical filling amount per pile is calculated as "pile diameter × pile length × porosity × 1.1 (filling coefficient)" (e.g., pile diameter 1.2m, pile length 100m, filling amount ≈ 1.2). 2 ×π / 4×100×0.3×1.1≈37.4m 3 );

[0080] Layered stone filling: Start the winch and slowly lift the vibratory compactor (lifting height 0.5m) to fill the pile hole with crushed stone. The loose filling thickness of each layer is 50-80cm (measured with a measuring rope). After filling the stone, gently lower the vibratory compactor to the surface of the crushed stone to avoid the crushed stone being suspended in the air. Repeat the "lift-fill stone-lower" process until the crushed stone is filled to 1.0m below the design elevation of the pile top (to reserve space for dense grouting).

[0081] Technical objective: To form a uniform crushed stone skeleton, providing channels and support for cement grout penetration and bonding in the subsequent densification stage, and avoiding the problem of "uneven stone filling leading to local loosening of the pile body" in traditional vibratory crushed stone piles.

[0082] 3. Layered densification + synchronous cement grouting stage (core innovative process to form composite cemented pile body)

[0083] This stage represents a key innovation: building upon the traditional "layered densification" of vibro-compacted stone piles, cement grout is injected simultaneously. Through "vibratory compaction + 360° rotation," a uniform mixture of "crushed stone, cement grout, and gravel" is achieved, replacing the traditional "pure crushed stone without binder" structure.

[0084] Preset parameters for grouting: Parameters are set according to the gravel particle size.

[0085] Fine gravel layer (particle size 5-50mm): vibration frequency 25-30Hz, rotation speed 8-10r / min, grouting pressure 12-15MPa, grouting volume 0.6-0.7m. 3 / m;

[0086] Medium-sized gravel layer (particle size 50-100mm): vibration frequency 30-35Hz, rotation speed 7-8r / min, grouting pressure 15-17MPa, grouting volume 0.7-0.8m. 3 / m;

[0087] Coarse gravel layer (100-300mm): Vibration frequency 35-40Hz, rotation speed 5-7r / min, grouting pressure 17-18MPa, grouting volume 0.8-0.9m. 3 / m;

[0088] First section (100-90m from the pile bottom) grouting:

[0089] Lower the vibratory compactor to the bottom of the pile and start the vibratory compactor (according to the parameters of the coarse gravel layer) + rotate (power head) + grouting;

[0090] The vibratory compactor is slowly raised at a speed of 0.1-0.2 m / min, which vibrates to compact the crushed stone (the porosity of the crushed stone after compaction is ≤20%). It rotates 360° to stir, and at the same time, cement slurry is injected through the grouting hole, seeps along the pores of the crushed stone, and mixes with the surrounding pebbles and crushed stone.

[0091] Real-time monitoring: The control system records the grouting volume per meter (deviation from preset value ≤10%), torque value (≤4500 N·m), and grouting pressure (fluctuation ≤1 MPa); if the torque exceeds the standard, the speed is automatically reduced and the frequency is increased; if the grouting pressure drops suddenly (grout loss), the lifting is paused, and grouting is maintained for 5 minutes before continuing;

[0092] Layered grouting (from 90m to 1.0m above the pile top):

[0093] Each 10m section is considered a single section. After completing the previous section, adjust the parameters for the next section (according to the change in gravel particle size) and repeat the process of "vibration-rotation-lifting-grouting".

[0094] When the grouting reaches 1.0m from the top of the pile, reduce the grouting pressure to 8-10MPa to reduce grout overflow and ensure the top of the pile is compacted.

[0095] Grouting treatment: After each section of densification is completed, if the grout level in the pile hole is more than 30cm lower than the crushed stone surface, cement grout should be injected until it is flush with the crushed stone surface to avoid voids in the pile body.

[0096] Technical objective: By simultaneously performing "densification + grouting", the cement slurry is uniformly diffused using vibration and rotation, solving the problems of "no bonding and low bearing capacity" in traditional vibro-compacted stone piles; the layer parameters are adjusted to adapt to gravel of different particle sizes, ensuring uniform mixing throughout the pile length, and the unconfined compressive strength of the pile body is ≥2.0MPa.

[0097] In some embodiments, the grouting process is monitored in real time by an equipped recorder to detect the grouting volume and grout loss alarms.

[0098] 4. Pile completion and quality inspection stage (ensuring pile integrity and strength)

[0099] 4.1. Pile head treatment and equipment cleaning

[0100] After the grouting is completed, shut down all systems and lift the vibratory compactor to the ground; cut off the 1.0m loose section reserved at the top of the pile (preserving the designed pile top elevation), clean the residual grout from the vibratory compactor (rinse with a high-pressure water gun), retract the telescopic guide rod (in the order of "inner rod → middle rod → outer rod"), and move the pile frame to the next pile position.

[0101] 4.2. Pile Maintenance and Quality Inspection

[0102] Maintenance: Cover the top of the pile with geotextile and water it for curing (curing period ≥28 days, water 2-3 times a day to keep the pile moist and prevent cracking).

[0103] 4.3 Experimental Data:

[0104] (i) The test piles adopt three sets of test piles with the same design standard to ensure the effectiveness of the comparison.

[0105] Pile length: 100m (target pile depth).

[0106] Design pile diameter: 1.2m;

[0107] Number of test piles per group: 3;

[0108] Test group: The present invention is "30m mast-type pile frame or rotary drilling rig + telescopic guide rod + vibratory compaction rotation integrated setting";

[0109] Control group 1: Traditional high-mast mixing pile equipment (pile frame height 65m, fixed mixing shaft + blades);

[0110] Control group 2: Traditional high-pressure jet grouting equipment (high-pressure grouting pump pressure ≥25MPa, jetting rod);

[0111] (II) Testing Basis and Methods

[0112] In accordance with national standards and industry norms, the data is guaranteed to be authoritative.

[0113] GB / T 50123-2019 Standard for Geotechnical Testing Methods;

[0114] JGJ 106-2014 Technical Specification for Testing of Building Foundation Piles;

[0115] Testing items: pile depth, pile integrity, unconfined compressive strength, vertical bearing capacity of a single pile, grout loss rate, construction safety and efficiency.

[0116] (III) Test Equipment

[0117] 1. Traditional mixing piles: completely lack the capability to form piles over 100 meters.

[0118] The inherent limitations of the process: mixing piles rely on a fixed-length mixing shaft and blades, and the construction depth is less than or equal to the height of the pile frame. The current industry's maximum pile frame height is less than or equal to 70m (corresponding to a maximum construction depth of less than or equal to 65m), and it requires a heavy-duty anti-overturning foundation, which cannot meet the requirements of a depth of 100 meters.

[0119] Geological compatibility defects: The gravel has a Mohs hardness of 6-8 and a maximum particle size of 300mm. The stirring blades (conventional material Q355) are prone to chipping and breakage. Even in medium-coarse gravel layers below 50m, the probability of the drill getting stuck is over 80%, making it impossible to penetrate to 100m.

[0120] 2. Traditional high-pressure jet grouting piles: While they can theoretically be drilled to depths of up to 100 meters, they lack effective pile formation.

[0121] Technological challenges: High-pressure jet grouting piles, by lowering the jetting head through the drill rod, can theoretically drill to 100m, but there are three fatal problems with gravel layers:

[0122] Borehole wall collapse: Without cohesive soil cementation, the borehole wall has no self-stabilizing ability after drilling. Even with mud slurry wall protection, the collapse rate below 50m is ≥90%, making it impossible to maintain the pile channel.

[0123] Complete loss of grout: At a depth of 100 meters, the high-pressure grout (≥25MPa) flows through the pores of the gravel, with a loss rate of over 60%, making it impossible to form a cementitious body within the pile body.

[0124] Insufficient drill rod stability: The slenderness ratio of the 100-meter drill rod is too large, making it prone to bending and deformation, causing the jetting direction to deviate, resulting in the pile body having no formed shape.

[0125] (iv) Experimental data

[0126] Table 1 Comparative Experiments

[0127]

[0128] Table 2. Completion status of mixing piles (process limitations prevented the piles from reaching 100m).

[0129]

[0130] Table 3. High-pressure jet grouting pile formation status (no effective piles formed)

[0131]

[0132] Table 4. Parameters of a single-stage vibration construction in a certain geological area

[0133]

[0134] Table 5. Construction parameters of single-stage vibratory grouting in a certain geological area.

[0135]

[0136] Experimental conclusions

[0137] Traditional mixing piles suffer from inherent limitations in pile frame height and blade penetration capability, making them unsuitable for pile driving through 100-meter-deep gravel layers. The industry standard is a maximum pile frame height of 65m and a maximum pile depth of 55-62m. In medium-coarse gravel layers, the larger particle size of deeper gravel complicates the process, resulting in insufficient mixing shaft torque and insufficient blade agitation to break up the gravel. This inability to overcome the resistance of large-diameter gravel inevitably leads to drill jamming and shaft bending.

[0138] As shown in Tables 4 and 5, for pile construction in 100-meter gravel layers, in the construction process of this invention, the changes in two key parameters of the vibratory compactor (vibration frequency and rotation speed of the vibratory compactor) need to simultaneously meet the following conditions:

[0139] Condition 1: The vibration frequency of the vibratory compactor is positively correlated with the construction depth (including drilling and densification). The deeper the construction depth (in units of 10m), the higher the vibration frequency of the vibratory compactor.

[0140] Condition 2: When the construction depth (including drilling and densification) is between 0 and 70 m, the rotation speed of the vibratory compactor remains constant (e.g., always maintained at 10 r / min). When the drilling depth is between 70 and 100 m, the rotation speed of the vibratory compactor is gradually reduced as the drilling depth increases to prevent hole collapse. When the densification depth is between 70 and 100 m, the rotation speed of the vibratory compactor is reduced but remains constant to improve the uniformity of densification.

[0141] Gravel layers are often considered a type of coarse-grained soil, but in actual engineering, they are rarely a simple accumulation of rock fragments. Depending on their geological origin and environmental differences, they often contain a variety of unique geological components that can significantly alter the physical and mechanical properties of the strata.

[0142] For example: carbonate rock fragments: in limestone distribution areas, pebbles are mostly composed of weathered or broken limestone blocks, and the surface often has dissolution cavities.

[0143] Quartzite / granite fragments: extremely hard and difficult to break by machinery, they are the "hardest nuts to crack" in tunnel excavation.

[0144] If such geological obstacles are encountered during construction, causing construction difficulties, it is necessary to increase the vibration frequency of the vibratory compactor and reduce its rotation speed to break through the stratum. For example, in Tables 4 and 5, when construction obstacles are encountered at 20-30 meters, the vibration frequency of the vibratory compactor is increased from 25Hz to 35Hz, while the rotation speed is reduced from 10r / min to 5r / min. After breaking through the geological stratum, the vibration frequency and rotation speed of the vibratory compactor are restored to the preset values.

[0145] High-pressure jet grouting piles have the core contradiction of "hole wall collapse and complete loss of grout". Even if the hole is drilled to a depth of 100 meters, the pores of the gravel are more interconnected, and the high-pressure grout spreads without restraint. After the collapse, the soil and gravel on the hole wall mix, and the grout cannot form an effective coating. The strength is <0.5MPa, there is no cementing effect, and it has no engineering significance.

[0146] This invention successfully achieves drilling to a depth of 100 meters through a gravel layer using a vibratory compactor in conjunction with a pile frame and telescopic guide rod, solving the problems of stuck drill and hole collapse. After reaching a depth of 100 meters, high-pressure cement grout and stone are injected. During the lifting process, the vibratory compactor not only compacts the surrounding soil, thus increasing the bearing capacity of the soil between piles, but also achieves the pile diameter and penetration effect of grouting jet grouting piles, with data consistent with the advantages of the process.

[0147] The key point and core of this invention is to achieve an integrated design of "ultra-deep penetration, vibration compaction, rotational stirring, and precise spraying" through vibratory compaction process.

[0148] 1. The vibratory compactor's vibration and 360° rotation enable penetration and mixing (replacing the blades of the mixing pile).

[0149] 2. The vibratory compactor uses a grouting pipe for spraying grout (replacing high-pressure jet grouting in rotary grouting). High-pressure clean water is used for hole drilling, and cement grout is used for densification. The cement grout is vibrated and squeezed into the gravel strata. The spraying adopts the internal main channel structure of the vibratory compactor: the central channel is the main grouting channel (50-80mm in diameter), ensuring that the grout is directly injected into the mixing zone as it rotates;

[0150] 3. The sliding rod / self-locking rod telescopic guide rod is suitable for a depth of 100 meters (replacing the traditional fixed shaft). When used with a 30-meter pile frame, it can ultimately realize the construction process of 100-meter vibratory mixing piles and jet grouting piles, completely replacing the traditional mixing piles and jet grouting piles construction process.

[0151] Furthermore, it should be understood that those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A super-hundred-meter vibroflotation mixing pile and jet grouting pile equipment, characterized in that: The power frame, the rotary suspension head, the follow-up frame, the telescopic guide rod, the power head, the grouting system, the vibrator, and the hoist, The telescopic guide rod is installed in front of the power frame, the upper section of the telescopic guide rod is connected with the rotary suspension head and the power head, and the lower end of the telescopic guide rod is connected with the vibrator, and the power head is used to drive the vibrator to rotate; The grouting system comprises a cement bin, a slurry pump, a cement slurry pipe, a cement slurry channel in the telescopic guide rod, and a grouting pipe, the slurry pump is in communication with the cement bin, one end of the cement slurry pipe is in communication with the slurry pump, the other end of the cement slurry pipe is in communication with the cement slurry channel, and the cement slurry channel is in communication with the grouting pipe; The top of the power frame is provided with an anchor hoisting frame, and the steel wire rope of the hoist is connected with the rotary suspension head through the anchor hoisting frame; The upper section of the telescopic guide rod is slidably connected with the power frame through the follow-up frame.

2. The over-hundred-meter vibroflotation mixing pile and jet grouting pile equipment according to claim 1, characterized in that: The vibrator is externally provided with a spiral crushing stirring tooth; And / or, The power frame is one of a mast type pile frame, a rotary drilling rig, and an excavator body.

3. The over-hundred-meter vibroflotation mixing pile and jet grouting pile equipment according to claim 1, characterized in that: The grouting system further comprises a rotary slurry adapter valve, which is installed between the cement slurry pipe and the cement slurry channel.

4. The over-hundred-meter vibroflotation mixing pile and jet grouting pile equipment according to claim 1, characterized in that: The outer wall of the telescopic guide rod is provided with a guide rod lock key.

5. The construction process of the super-hundred-meter vibroflotation mixing pile and jet grouting pile equipment according to any one of claims 1-4, characterized in that, The method comprises the following steps: The vibrator rotation frequency and the construction depth are positively correlated in the encryption stage, and the rotation speed of the vibrator remains unchanged during the encryption process with a depth of 0-70 m; when the encryption depth is above 70 m, the rotation speed of the vibrator is reduced and remains unchanged. The vibrator rotation frequency and the construction depth are positively correlated in the encryption stage, and the rotation speed of the vibrator remains unchanged during the encryption process with a depth of 0-70 m; when the encryption depth is above 70 m, the rotation speed of the vibrator is reduced and remains unchanged. For the construction of the gravel layer, if carbonate rock debris or quartzite / granite fragments are encountered during the construction process, the construction is carried out by increasing the vibration frequency of the vibrator and reducing the rotation speed of the vibrator.

6. The construction process of claim 5, wherein: For the construction of the gravel layer, if carbonate rock debris or quartzite / granite fragments are encountered during the construction process, the construction is carried out by increasing the vibration frequency of the vibrator and reducing the rotation speed of the vibrator. ​ ​ 7. The construction process of claim 5, wherein: In the process of hole making, if the hole wall collapses, the method of filling stone during hole making is adopted until the designed depth is reached, the vibrator is temporarily lowered, the grouting system is started for low pressure grouting, the grouting pressure is 5-8 MPa, and the grouting amount is 0.2-0.3 m per meter of pile length 3 Grouting is carried out.

8. The construction process of claim 5, wherein: ​ If the geology is a fine pebble layer with a particle size of 5-50 mm, the construction parameters are: vibrator vibration frequency 25-30 Hz, vibrator rotation speed 8-10 r / min, grouting pressure 12-15 MPa, and grouting amount 0.6-0.7 m 3 / m; If the geology is a medium pebble layer with a particle size of 50-100 mm, the construction parameters are: vibrator vibration frequency 30-35 Hz, vibrator rotation speed 7-8 r / min, grouting pressure 15-17 MPa, and grouting amount 0.7-0.8 m 3 / m; If the geology is a coarse pebble layer with a particle size of 100-300 mm, the construction parameters are: vibrator vibration frequency 35-40 Hz, vibrator rotation speed 5-7 r / min, grouting pressure 17-18 MPa, grouting amount 0.8-0.9 m 3 / m; ​ ​ 9. The construction process of claim 5, wherein: ​ ​ 10. The construction process of claim 9, wherein: ​

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