An adjustable pneumatic shock absorber, vibroflotation construction equipment and vibroflotation construction process

Abstract

The present application relates to a kind of adjustable air pressure shock absorber, vibroflotation construction equipment, vibroflotation construction process, belong to the field of vibroflot accessory.The adjustable air pressure shock absorber includes upper sleeve shell and lower tube shaft, and buffer assembly is arranged between the two, which is composed of multiple internally inflated tire rings.The air pressure in tire ring can be dynamically adjusted by external control system to realize continuous adjustable stiffness.The vibroflotation construction equipment is integrated with acceleration acquisition unit and control module, the control module executes control law algorithm, generates and outputs target air pressure with different waveform characteristics according to guide rod vibration acceleration envelope amplitude, corresponding to four working modes, to respectively cope with homogeneous stratum drilling, sudden quasi-resonance, large particle size pebble layer drill and soft stratum grouting and other complex conditions such as vibration.The present application realizes the active intelligent control of shock absorber stiffness and output waveform, significantly improves the safety and efficiency of vibroflotation construction.

Description

Technical Field

[0001] This invention relates to the field of vibratory compactor accessories, specifically an adjustable pneumatic shock absorber, vibratory compaction equipment, and vibratory compaction process. Background Technology

[0002] Vibro-compaction technology is widely used in foundation treatment projects. The high-frequency vibrations (10-60Hz, 5-15mm amplitude) generated by the vibro-compactor, its core equipment, must be effectively blocked by shock absorbers. Otherwise, fatigue damage to the upper structure, such as the frame, power head, and crane, will occur, reducing the equipment's service life. In existing technologies, the mainstream shock absorber uses cast rubber as an elastic connector, and the vibro-compactor core is fixedly connected to the vibro-compactor shell through a vulcanization process.

[0003] Long-term engineering practice has verified that existing cast-in-place rubber shock absorbers have the following significant technical defects:

[0004] 1) The stiffness of rubber materials is an inherent property and cannot be dynamically adjusted according to the construction scenario. When a 75kW low-power vibratory compactor is used in soft soil construction, the excessive stiffness of the rubber leads to over-buffering and severe equipment subsidence; while when a 225kW high-power vibratory compactor is used in hard rock construction, the insufficient stiffness leads to vibration damping failure and excessive vibration acceleration of the superstructure.

[0005] 2) Different power vibratory compactors require different specifications of casting rubber shock absorbers (e.g., 75kW corresponds to Φ300mm rubber body, 225kW corresponds to Φ400mm rubber body), which means that construction units need to keep a variety of specifications of accessories, increasing inventory management costs and reducing flexibility in scene switching.

[0006] Furthermore, the working environment of vibro-compaction equipment is extremely harsh and highly unpredictable during vibro-compaction operations. The strata it needs to penetrate are often alternating layers of soft and hard material, containing various geological structures such as fine sand, gravel, pebbles, and even boulders. During this process, the vibro-compaction equipment faces three typical and harmful kinetic challenges:

[0007] 1) Quasi-resonance phenomenon: When the excitation frequency of the vibratory impactor is coupled with the natural frequency of the ground-guide rod-frame system, it will cause severe resonance and damage to the superstructure.

[0008] 2) Drill jamming: In layers of large-diameter pebbles, the gravel can wed into the space between the vibratory compactor and the borehole wall, causing the drill to get stuck or jam, resulting in stagnant progress and a surge in current.

[0009] 3) Borehole wall instability: When grouting in soft soil layers (such as silty soft soil), the borehole wall is prone to creep and collapse, or improper pressure control may cause the grout to split along the cracks and cause cross-holes.

[0010] These complex operating conditions require vibration damping systems to not only passively buffer but also actively, quickly, and intelligently respond and adjust their own characteristics. However, existing cast rubber vibration dampers are passive components and cannot achieve this goal.

[0011] Based on this, the present invention is proposed. Summary of the Invention

[0012] This invention addresses the shortcomings of existing technologies by providing an adjustable pneumatic shock absorber, vibratory compaction equipment, and vibratory compaction process. The technical solution is as follows:

[0013] In a first aspect, an adjustable pneumatic shock absorber includes an upper housing and a lower tube shaft coaxially arranged with the upper housing. A buffer assembly is provided between the upper housing and the lower tube shaft. The buffer assembly includes multiple sets of tire bead rings, the inner ring of which is provided with a bead ring with an opening. The lower tube shaft includes a vertical tube body and a flange tube fixedly connected to the lower end of the vertical tube body. The outer wall of the vertical tube body is provided with a bead seat that matches the inner ring of the tire bead ring. The outer ring of the bead seat is provided with a bead groove that matches the bead ring of the tire bead ring. The tire bead ring is fitted onto the upper housing. The tire bead seat is located outside the tire bead seat, and the inner ring of the tire bead is sealed to the tire bead seat. The upper part of the vertical tube body is provided with a vent, and the outer side wall of the vertical tube body is also provided with an air hole that communicates with the opening. The inner cavity of the tire bead is connected to the vent through the air hole. The upper shell includes multiple sets of shell unit groups for covering the tire bead. Each shell unit group consists of two shell units. The shell unit is located outside the tire bead, and the structure of the inner side of the shell unit matches the structure of the outer side of the tire bead. Adjacent shell units are fixedly connected.

[0014] Furthermore, it also includes an external control system, in which the inner cavities of all tire rims are interconnected to form a common air chamber. The external control system includes a four-way control valve group, an air source, and a pressure relief valve. The four-way control valve group includes a four-way pipe fitting and solenoid valves installed at the four joints of the four-way pipe fitting. The common air chamber is connected to the first solenoid valve of the four-way control valve group, the air source is connected to the second solenoid valve of the four-way control valve group, and the pressure relief valve is connected to the third solenoid valve of the four-way control valve group.

[0015] Furthermore, the external control system also includes a pressure dynamic adjustment component for dynamically adjusting the air pressure inside the main air chamber. The pressure dynamic adjustment component includes a volumetric pneumatic conversion element and a vibration actuator for applying vibration to the volumetric pneumatic conversion element.

[0016] The air chamber inside the volumetric pneumatic conversion element is connected to the fourth solenoid valve of the four-way control valve group;

[0017] When the second and third solenoid valves of the four-way control valve group are both closed and the first and fourth solenoid valves of the four-way control valve group are both open, the vibration actuator applies vibration to the volumetric pneumatic converter element, causing dynamic changes in the air pressure of the air chamber and the total air chamber within the volumetric pneumatic converter element.

[0018] Furthermore, the volumetric pneumatic conversion element is a high-pressure airbag or an air spring, and the vibration actuator is a vibrator or an actuator.

[0019] Furthermore, there are two tire bead rings, with the first tire bead ring located above the second tire bead ring; the ratio of the volume of the inner cavity of the first tire bead ring to the volume of the inner cavity of the second tire bead ring is x, where 0.98 ≤ x ≤ 0.99.

[0020] Furthermore, retaining rings are installed on the upper and lower sides of the tire bead.

[0021] Secondly, the vibratory compaction equipment includes a vibratory compactor, which includes a vibratory compactor body and a guide rod. An adjustable pneumatic shock absorber is provided between the lower end of the guide rod and the upper end of the vibratory compactor body. The lower end of the guide rod is fixedly connected to the upper end of the upper casing, and the upper end of the vibratory compactor body is fixedly connected to a flange pipe. A high-pressure air pipe is provided inside the guide rod, and one end of the high-pressure air pipe is connected to a ventilation channel.

[0022] Furthermore, the vibratory compaction equipment also includes a control module, which comprises:

[0023] The acceleration acquisition unit is used to acquire the vibration acceleration envelope amplitude A of the guide rod. n ;

[0024] Control law algorithm execution unit;

[0025] Sine wave generator;

[0026] The vibration acceleration envelope amplitude A n The input control law algorithm execution unit executes the control law algorithm, and the formula for the control law algorithm is as follows:

[0027] ;

[0028] Where, θ n θ refers to the instantaneous phase angle accumulated by the sine wave generator at the nth control cycle. n+1 The instantaneous phase angle accumulated by the sine wave generator at the (n+1)th control cycle; P set δ is the preset reference pressure; δ is the amplitude of the micro-perturbation, which is the maximum amplitude of the sinusoidal perturbation component superimposed on the preset reference pressure; f0 is the fundamental frequency; α is the coupling coefficient; Δt is the control period; It is A nThe previous historical value;

[0029] The target air pressure P was calculated. n+1 ;

[0030] Based on the target air pressure P n+1 The air pressure inside the main air chamber is adjusted by the air pressure dynamic adjustment component of the external control system.

[0031] Furthermore, based on the vibration acceleration envelope amplitude A n The characteristics of change, product term The target air pressure is automatically displayed in four waveform modes, each corresponding to different construction geological conditions and working conditions:

[0032] Mode 1: Stable sinusoidal micro-vibration mode

[0033] Corresponding geology: Homogeneous strata with stable bearing capacity, such as deep silty sand layers and medium-dense sand layers, with smooth drilling and no obvious vibration anomalies.

[0034] Vibration characteristics: A n The fluctuations are minimal across multiple control cycles, and the adjacent differences are... .

[0035] When the difference approaches zero, the product term The equation degenerates into That is, the phase increases linearly with a constant angular velocity of 2πf0. Substituting into the equation... This yields a standard sine wave with a constant frequency of f0 and a constant amplitude of δ.

[0036] Judgment criterion: Within a sliding time window of length N control cycles, the amplitude of the vibration acceleration envelope A n When the difference between the maximum and minimum values ​​is less than a first preset threshold, the target air pressure P n+1 It is a sine wave with frequency f0 and amplitude δ;

[0037] Where N is an integer greater than 1, and the first preset threshold is an empirical calibration value;

[0038] For example: the first preset threshold is an empirical statistical value of the amplitude fluctuation range during normal drilling.

[0039] Mode 2: Phase abrupt change perturbation mode

[0040] Corresponding geology: alternating layers of soft and hard soil, gravel and lenses. When the vibratory compactor passes through strata of different stiffness, the system’s natural frequency and excitation frequency coincide by chance, causing quasi-resonance.

[0041] Vibration characteristics: A n A unidirectional, sharp surge occurred within an extremely short period of time; the difference... It is a relatively large positive value.

[0042] When A n When the value increases sharply, both the difference and the current amplitude are large, and the product term... This generates a positive additional phase increment far exceeding 2πf0Δt, causing θ to jump discontinuously within a single control cycle (the phase increment can reach several radians, far exceeding the normal 0.4π radians / step). This discontinuous phase jump causes tearing in the output sine wave in the time domain; the originally smooth sine waveform exhibits sudden phase misalignment, deviating from the regular sine wave at frequency f0. This phase-disordered waveform causes irregular jumps in the equivalent stiffness of the damper, fundamentally disrupting the stable phase accumulation condition required for resonance.

[0043] Judgment criterion: Within a sliding time window of length N control cycles, the amplitude of the vibration acceleration envelope A n When the difference between the maximum and minimum values ​​exceeds the second preset threshold;

[0044] Where N is an integer greater than 1, and the second preset threshold is an empirical calibration value; for example, the second preset threshold is an empirical boundary value that distinguishes between normal fluctuations and resonant bursts.

[0045] Mode 3: High-frequency vibration mode

[0046] Corresponding geology: Large-diameter pebble layer, boulder layer, crushed stone embedded and stuck in the vibratory drill, causing the drill to stall and the progress to stop but without resonance.

[0047] Vibration characteristics: A n It exhibits continuous, intense high-frequency positive and negative fluctuations, with adjacent differences. The positive and negative signs change frequently, but the amplitude does not show a unidirectional upward trend.

[0048] The vibration during drilling is chaotic and undirected, A n Frequent fluctuations cause the product term to... The positive and negative signs alternate synchronously at high frequency. This makes the phase increment... Based on 2πf0Δt, the wave is alternately pushed (positive increment) and pulled (negative increment), forming a continuous high-frequency phase push-pull. The phase push-pull causes the instantaneous frequency of the sine wave to fluctuate rapidly over a wide range. The single frequency energy originally concentrated at f0 diffuses to the frequency bands on both sides of f0, and the waveform evolves from a regular sine wave to a high-frequency fragmentation vibration with a broadened spectrum. This fragmentation vibration is transmitted to the bottom of the hole through the guide rod, generating micro-impact disturbances with irregular frequency and amplitude on the compacted gravel, effectively destroying the embedded arch structure between the gravel.

[0049] Judgment condition: Within a sliding time window of length M control cycles, the following conditions must be met simultaneously:

[0050] Condition 1: Vibration acceleration envelope amplitude A nThe difference between the maximum and minimum values ​​exceeds the third preset threshold;

[0051] Condition 2: Amplitude difference between adjacent periods The number of times the positive and negative signs alternate exceeds the fourth preset threshold;

[0052] The product term increases the phase increment between adjacent periods. The deviation Δε from 2πf0Δt n The positive and negative signs of the pressure change more than the fifth preset threshold number of times within the sliding time window, and the target air pressure P n+1 Within the sliding time window, the normalized power percentage at frequency f0 decreases to below the sixth preset threshold.

[0053] Where M is an integer greater than 1, and the third, fourth, fifth, and sixth preset thresholds are all empirically calibrated values; for example:

[0054] The third preset threshold is an empirical value representing the typical window range of drill breakage and vibration.

[0055] The fourth preset threshold is an empirical boundary value that distinguishes between unidirectional spikes and high-frequency jitter.

[0056] The fifth preset threshold is the empirical limit value that confirms the continuous push-pull effect of the product term;

[0057] The sixth preset threshold is the empirical limit value that distinguishes between single-frequency sine waves and spectral broadened waves;

[0058] The seventh preset threshold is an empirical value that can be used to detect the lower limit of amplitude fluctuations during the grouting stage.

[0059] in, For reference values, the threshold is set to 10 times or more, for example, when M=20.

[0060] Mode 4: Micro-vibration mode

[0061] Corresponding geology: In the stage of segmented grouting and vibration retention, the borehole wall is prone to creep and collapse due to loss of dynamic support, or the grout splits along the weak surface, resulting in grout leakage between adjacent boreholes.

[0062] Vibration characteristics: A n It exhibits slow, small-amplitude quasi-periodic fluctuations, with a period of 2 to 3 seconds, consistent with the rhythm of formation reaction force changes caused by borehole wall instability or abnormal slurry flow.

[0063] During the grouting and vibration stage, minute creep of the borehole wall soil or grout flow will cause slow, periodic changes in the ground reaction force at the vibratory compactor tip, reflected as A. n Quasi-periodic fluctuations. Product term This results in a periodic alternation of positive and negative additional phase increments, the magnitude and direction of which vary with A.n The fluctuations change synchronously. This causes the instantaneous frequency of the output waveform to drift slowly around f0, while the amplitude of the waveform envelope follows A. n The synchronous increase and decrease create a breathing-like, undulating non-periodic wave. This waveform maintains a dynamically changing micro-stress field within the borehole wall, equivalent to providing continuously fine-tuned dynamic support to the borehole wall. At the same time, the unstable pressure pulsations disrupt the conditions required for the slurry to continuously split along a single weak surface.

[0064] Within a sliding time window of length L control cycles, the following conditions are met:

[0065] Condition 1: Vibration acceleration envelope amplitude A n The difference between the maximum and minimum values ​​is greater than the seventh preset threshold.

[0066] Condition 2: Condition 1 is true for K consecutive sliding time windows, and then a sliding time window appears where Condition 1 is not true.

[0067] Condition 3: The process of Condition 2 is repeated at least R times within the preset total observation time, and the fluctuation range of the number of sliding time windows between two adjacent initial sliding time windows that satisfy Condition 1 does not exceed ±T%.

[0068] but:

[0069] Target air pressure P within the sliding time window n+1 The maximum deviation between the instantaneous frequency of the waveform and f0 exceeds the eighth preset threshold.

[0070] Target air pressure P n+1 The amplitude of the sliding envelope of the waveform and the amplitude of the vibration acceleration envelope A n The correlation coefficient exceeds the ninth preset threshold;

[0071] Where L, K, and R are integers greater than 1, T is the preset percentage tolerance, and the seventh, eighth, and ninth preset thresholds are all empirical calibration values.

[0072] The value of L is determined based on 2 to 3 seconds, covering the complete cycle of grouting fluctuations.

[0073] The value of K is determined based on the fact that the amplitude exceeding the threshold is not an instantaneous or accidental event;

[0074] The value of R is determined based on the confirmation that there is a quasi-periodicity rather than a single event;

[0075] The value of T is determined based on the allowable period having a certain degree of non-uniformity;

[0076] The seventh preset threshold is the lower limit of the perceptible amplitude fluctuation during the grouting stage;

[0077] The eighth preset threshold is the threshold for judging the instantaneous frequency deviation from f0;

[0078] The ninth preset threshold determines the envelope amplitude and A n Highly relevant thresholds.

[0079] Fourthly, the vibratory compaction construction process involves using the aforementioned vibratory compaction equipment for construction, employing vibratory compactors for hole making and compaction.

[0080] Compared with the prior art, the beneficial effects of the present invention are:

[0081] 1. By adjusting the tire pressure in real time through an external control system, the stiffness of the shock absorber can be continuously adjusted within the air pressure range of 0.3~1.2MPa. One set of equipment can be adapted to vibratory impactors with different power from 75~225kW, which significantly improves the versatility of the equipment and reduces the spare parts inventory cost of construction units.

[0082] 2. The control module monitors the vibration acceleration of the guide rod in real time and executes the control law algorithm, enabling it to spontaneously identify and handle various complex working conditions:

[0083] ① Resonance Suppression: When the system experiences quasi-resonance (mode 2), the algorithm disrupts the resonance energy accumulation conditions through phase abrupt changes, and can suppress the vibration acceleration to below the safety threshold within a few seconds (2.1s in the example), effectively protecting key equipment such as the frame and power head, and avoiding downtime for maintenance due to severe vibration.

[0084] ② Automatic Unblocking: When drilling stalls in the pebble layer (Mode 3), the algorithm actively generates a high-frequency vibration waveform to apply irregular micro-impact disturbances to the gravel accumulation layer at the bottom of the hole, effectively destroying the embedded arch structure between the gravel and achieving automatic unblocking. This reduces the number of hole-cleaning operations commonly found in traditional construction by more than 80%, significantly improving construction efficiency.

[0085] ③ Wall protection and anti-crossing: When grouting with vibration retention in soft strata (mode 4), the algorithm outputs micro-vibration mode air pressure waveform to maintain a dynamic stress field on the borehole wall, effectively suppressing soft soil creep and collapse, and reducing the probability of grout splitting along a single weak surface (grout cross-cutting between adjacent boreholes) to less than 1 / 3 of the traditional method, which significantly improves the pile quality and construction safety.

[0086] 3. The upper casing of the present invention adopts a split casing unit design, which allows for the inspection and replacement of the internal tire bead without complete disassembly, reducing maintenance difficulty and time cost. Attached Figure Description

[0087] Figure 1 This is a schematic diagram of the adjustable pneumatic shock absorber described in this invention;

[0088] Figure 2 This is a schematic diagram of the structure of the vertical tube body described in this invention;

[0089] Figure 3 A schematic diagram of the structure of the vibratory impactor described in this invention;

[0090] Figure 4 This is a schematic diagram of the internal structure of the vibratory impactor described in this invention;

[0091] Figure 5 This is a schematic diagram showing the connection of the main air chamber, four-way control valve group, pressure relief valve, air source, and volumetric pneumatic conversion element described in this invention. Detailed Implementation

[0092] 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.

[0093] Example 1

[0094] like Figure 1 , 2 As shown, an adjustable pneumatic shock absorber includes an upper housing and a lower tube shaft coaxially arranged with the upper housing. A buffer assembly is provided between the upper housing and the lower tube shaft. The buffer assembly includes multiple sets of tire bead rings 23, the inner ring of which is provided with a tire bead with an opening. The lower tube shaft includes a vertical tube body 22 and a flange tube 21 fixedly connected to the lower end of the vertical tube body 22. The outer wall of the vertical tube body 22 is provided with a tire bead seat 222 that matches the inner ring of the tire bead ring 23. The outer ring of the tire bead seat 222 is provided with a tire bead groove 221 that matches the tire bead of the tire bead 23. The tire bead 23 is sleeved on the outer ring of the tire bead seat 222. The inner ring of the tire bead 23 is sealed to the bead seat 222; the upper part of the vertical tube 22 is provided with a vent 223, and the outer wall of the vertical tube 22 is also provided with an air hole 224 communicating with the opening. The inner cavity of the tire bead 23 is connected to the vent 223 through the air hole 224; the upper shell includes multiple sets of shell unit groups for covering the tire bead 23. Each shell unit group consists of two shell units 24. The shell unit 24 is located on the outside of the tire bead 23, and the structure of the inner side of the shell unit 24 matches the structure of the outer side of the tire bead 23. Adjacent shell units 24 are fixedly connected.

[0095] When the adjustable air pressure shock absorber is in use, the upper housing is fixed to the upper device, the lower tube shaft is fixed to the lower device, and the buffer between the upper device and the lower device relies on the buffer assembly; in this embodiment, the buffer assembly mainly relies on multiple inflatable tire rings 23.

[0096] For ease of installation, the upper housing adopts a modular design, and adjacent housing units 24 can be fixedly connected by bolts.

[0097] The vent 223 can be connected to an external air source, thereby enabling simultaneous inflation and deflation of the inner cavity of the tire bead 23.

[0098] The sealing connection between the inner ring of the tire bead 23 and the bead seat 222 is a conventional technology. For example, the installation connection structure between a car's tubeless tire and the wheel hub relies on the fact that during inflation, as the internal air pressure increases, the enormous pressure will press the inner edge of the tire bead 23 (the bead) firmly against the groove wall of the bead groove 221. This physical compression will form an extremely tight fit, ensuring that air will not leak from the joint. Furthermore, if there are concerns about air leakage, adhesive bonding can be used for further sealing; or a mortise and tenon structure can be used to engage and position the tire bead.

[0099] In some other embodiments, to ensure the installation result, retaining rings 27 are installed on the upper and lower sides of the tire bead 23. The retaining rings 27 cooperate with the steel wire rings embedded in the tire bead 23, which can better fix the two, and at the same time facilitate the rubber at the tire bead to be squeezed and deformed to form a seal.

[0100] In some other embodiments, the housing unit 24 and the tire bead 23 may be glued together; or they may not be glued together, but only matched with a mortise and tenon structure.

[0101] Example 2

[0102] Based on Example 1, the adjustable pneumatic shock absorber 3 is applied to vibratory compaction equipment, which includes a vibratory compactor, such as... Figure 3 , 4 As shown, the vibratory shock absorber includes a vibratory shock absorber body 1 and a guide rod 2. An adjustable pneumatic shock absorber 3, as described in Embodiment 1, is provided between the lower end of the guide rod 2 and the upper end of the vibratory shock absorber body 1. The lower end of the guide rod 2 is fixedly connected to the upper end of the upper housing, and the upper end of the vibratory shock absorber body 1 is fixedly connected to the flange pipe 21. A high-pressure air pipe 4 is provided inside the guide rod 2. One end of the high-pressure air pipe 4 is connected to the air passage 223, and the other end of the high-pressure air pipe 4 can be connected to an air source, for example.

[0103] In the vibratory compaction equipment, the adjustable air pressure damper 3 is used to block the upward transmission of vibration; the tire bead 23 is equivalent to a tubeless heavy-duty tire, and the air pressure adjustment range inside the tire bead 23 is 0.3~1.2MPa, with an adjustment accuracy of ±0.05MPa. The tire bead stiffness can be continuously adjusted through air pressure adjustment, thereby adapting to vibratory compactors of different specifications such as 75kW, 130kW, 180kW, and 225kW.

[0104] In some embodiments, the high-pressure air pipe 4 can be a combination of a metal pipe and an armored flexible hose. The armored flexible hose is used to connect to the air passage 223. The armored flexible hose can be bent to a certain extent to meet the redundancy requirements of the adjustable air pressure shock absorber 3 during shock absorption. The high-pressure air pipe 4 can also be entirely made of armored flexible hose.

[0105] Example 3

[0106] Based on Example 1 or Example 2, for convenient inflation and deflation, such as Figure 5 As shown, the adjustable air pressure shock absorber also includes an external control system. The inner cavities of all tire bead 23 are interconnected and form a total air chamber 25. The external control system includes a four-way control valve group 6, an air source 8, and a pressure relief valve 7. The four-way control valve group 6 includes a four-way pipe fitting and solenoid valves installed at the four joints of the four-way pipe fitting. The total air chamber 25 is connected to the first solenoid valve of the four-way control valve group 6. The air source 8 is connected to the second solenoid valve of the four-way control valve group 6. The pressure relief valve 7 is connected to the third solenoid valve of the four-way control valve group 6.

[0107] Specifically, in the vibratory impactor, the other end of the high-pressure air pipe 4 is connected to the first solenoid valve of the four-way control valve group 6.

[0108] First, the gas source 8 can be a high-pressure gas cylinder or an air pump.

[0109] When inflation is required, the second solenoid valve of the four-way control valve group 6 opens, the first solenoid valve of the four-way control valve group 6 opens, and the other two solenoid valves close, so that the air source 8 inflates the main air chamber 25.

[0110] When pressure relief is required, the third solenoid valve of the four-way control valve group 6 opens, the first solenoid valve of the four-way control valve group 6 opens, and the other two solenoid valves close, opening the pressure relief valve 7, which can relieve pressure on the main air chamber 25.

[0111] Example 4

[0112] The external control system also includes a pressure dynamic adjustment component for dynamically adjusting the internal pressure of the main air chamber 25. The pressure dynamic adjustment component includes a volumetric pneumatic conversion element 9 and a vibration actuator for applying vibration to the volumetric pneumatic conversion element 9.

[0113] The air chamber inside the volumetric pneumatic conversion element 9 is connected to the fourth solenoid valve of the four-way control valve group 6;

[0114] When the second and third solenoid valves of the four-way control valve group 6 are closed and the first and fourth solenoid valves of the four-way control valve group 6 are open, the vibration actuator applies vibration to the volumetric pneumatic conversion element 9, causing dynamic changes in the air pressure in the air chamber and the total air chamber 25 within the volumetric pneumatic conversion element 9.

[0115] In some embodiments, the volumetric pneumatic conversion element 9 is a high-pressure airbag or an air spring, and the vibration actuator is a vibrator or an actuator. For example, in this case, the volumetric pneumatic conversion element 9 is a high-pressure airbag, which is continuously compressed under the action of the vibrator. When the initial air pressure in the total air chamber 25 is 1.2 MPa, the dynamic change in air pressure caused by mechanical compression at a frequency of 10 Hz can reach 0.05~0.15 MPa.

[0116] The vibratory compaction equipment also includes a control module, which comprises:

[0117] The acceleration acquisition unit is used to acquire the vibration acceleration envelope amplitude A of the guide rod. n ;

[0118] Control law algorithm execution unit;

[0119] Sine wave generator;

[0120] The vibration acceleration envelope amplitude A n The input control law algorithm execution unit executes the control law algorithm, and the formula for the control law algorithm is as follows:

[0121] ;

[0122] Where, θ n θ refers to the instantaneous phase angle accumulated by the sine wave generator at the nth control cycle. n+1 The instantaneous phase angle accumulated by the sine wave generator at the (n+1)th control cycle; P set δ is the preset reference pressure; δ is the amplitude of the micro-perturbation, which is the maximum amplitude of the sinusoidal perturbation component superimposed on the preset reference pressure; f0 is the fundamental frequency; α is the coupling coefficient; Δt is the control period; It is A n The previous historical value;

[0123] The target air pressure P was calculated. n+1 ;

[0124] According to the target air pressure P n+1 The air pressure inside the main air chamber is adjusted by the air pressure dynamic adjustment component of the external control system.

[0125] Example 5

[0126] Example of vibro-compaction construction of approach bridge foundation in a certain area:

[0127] The geological profile from top to bottom is as follows: 0-7m silty fine sand (medium-dense), 7-14m interbedded sand and gravel (pebble content 30%-55%, interspersed with porous medium-fine sand lenses), and 14-19m silty soft soil. A 130kW vibratory compactor was used, with a hole diameter of 800mm and a target depth of 18m, and the piles were constructed by segmented grouting.

[0128] Algorithm parameter presets: Preset reference pressure P set =0.7MPa, δ=0.08MPa, f0=10Hz, α=1.2, Δt=0.02s, initial phase θ0=0. Sliding time window lengths N=25 cycles (0.5s), M=30 cycles (0.6s), L=125 cycles (2.5s). The preset thresholds are calibrated based on previous tests in this project as follows:

[0129] The first preset threshold is 0.4 m / s 2 The second preset threshold is 6.0 m / s. 2 The third preset threshold is 4.0 m / s. 2 The fourth preset threshold is 10 times; the fifth preset threshold is 15 times; the sixth preset threshold is 70%; and the seventh preset threshold is 1.2 m / s. 2 The eighth preset threshold is 2.0Hz; the ninth preset threshold is 0.75; K is 4 windows; R is 3 times; T is 3 windows.

[0130] (1) Normal drilling in 0~7m fine sand layer (mode 1)

[0131] The amplitude of the vibration acceleration envelope of this section of the guide rod is A. n Stable at 2.5~3.2 m / s 2 The window range remains below the first preset threshold. The control law output is stable. Sinusoidal micro-vibration. This micro-vibration is transmitted to the guide rod through a shock absorber, effectively reducing the friction coefficient between the vibratory compactor and the borehole wall. Compared with construction with the same parameters without active control, the vibratory compactor motor current is reduced by approximately 10%, and the advance speed is increased by approximately 12%.

[0132] (2) Drilling holes in 7~14m interbedded gravel and sand

[0133] When drilling reached a depth of 9.2m and encountered alternating layers of gravel and lens material, the guide rod suddenly experienced violent, low-frequency shaking. A n From 3.1 m / s in 0.3 s 2 Soaring to 10.8 m / s 2 The range of the 25-period window reaches 7.7 m / s. 2This exceeds the second preset threshold. The product term causes the phase increment to deviate instantaneously from 2πf0Δt, transforming the stable 10Hz sine wave into a chaotic disturbance waveform with abrupt phase changes. The equivalent stiffness of the shock absorber changes erratically, and the vibration acceleration is suppressed to 4.5 m / s² within 2.1 s. 2 The rack shaking stopped immediately, and the entire process was completed automatically without stopping the machine.

[0134] When drilling reached 11.8m, a layer of large-diameter pebbles was encountered, causing the vibratory compactor to suddenly stall, halting the advance and causing a sudden surge in current. At this point, A n It exhibits continuous and intense high-frequency positive and negative fluctuations, with a range of 4.8 m / s within a 30-cycle window. 2 (Exceeding the third preset threshold of 4.0 m / s) 2 The sign of the amplitude difference between adjacent cycles alternates 18 times (exceeding the fourth preset threshold of 10 times). The product term drives the phase deviation Δε. n The symbol alternation reached 20 times (exceeding the fifth preset threshold of 15 times), and the normalized power ratio of the f0 frequency component dropped to 52% (below the sixth preset threshold of 70%), confirming a high-frequency fragmentation vibration mode. This fragmentation vibration was applied to the bottom of the hole via a guide rod, generating continuous and irregular micro-impact disturbances. After 3 seconds, the accumulated pebbles loosened, and the drilling progress resumed. In subsequent construction of this layer, the drill jamming phenomenon occurred on average once every 2 meters, and the algorithm automatically solved all of them. No manual lifting and rinsing of the hole was performed during the entire drilling process, reducing the number of rinsing operations by more than 80% compared to conventional construction, and shortening the total drilling time for this section by 28%.

[0135] (3) Segmented grouting in silty soft soil at depths of 14-18m

[0136] After drilling to 18m, the vibratory compactor is raised to 14m and grouting begins in sections from bottom to top, with vibration retention. During the grouting process, the vibratory compactor is affected by changes in the formation reaction force. n The amplitude is approximately ±1.5 m / s. 2 Quasi-periodic fluctuations with a period of approximately 2-3 seconds. The range of the 125-period window reaches 1.8 m / s. 2 (Exceeding the seventh preset threshold of 1.2m / s) 2 The condition was met for four consecutive windows before falling back down. This process repeated three times within the observation period, with adjacent initial window intervals of 125, 128, and 122, and the difference between any two pairs of windows did not exceed three windows (T=3). The maximum deviation of the instantaneous frequency of the target air pressure waveform from 10Hz reached 3.5Hz (exceeding the eighth preset threshold of 2.0Hz), and the sliding envelope amplitude of the air pressure waveform was also different from A. nThe Pearson correlation coefficient was 0.82 (exceeding the ninth preset threshold of 0.75), confirming it as a micro-vibration mode. This micro-vibration maintained a dynamic stress field within the borehole wall soil, effectively suppressing soft soil creep and collapse; simultaneously, unstable pressure fluctuations disrupted the conditions for continuous splitting of the grout along a single weak surface. In this example, a total of 20 piles were constructed in the test section, with only one borehole collapse (5%), and no cross-contamination of grout between adjacent boreholes occurred.

[0137] Comparative example to this case: Construction of traditional fixed pneumatic shock absorbers;

[0138] In the same engineering area, adjacent construction sections with consistent geological conditions were selected, and the same model of 130kW vibratory compactor was used. Traditional adjustable pneumatic shock absorbers without control modules were installed, and the air circuit was closed after being inflated to a fixed pressure of 0.7MPa. There was no active control throughout the process.

[0139] When drilling through the interbedded sand and gravel, three strong resonances lasting more than 10 seconds occurred due to changes in hardness, with the maximum vibration acceleration reaching 13.5 m / s². 2 This resulted in the guide rod connecting bolts loosening once, forcing a 20-minute shutdown for maintenance. The average time for single-hole drilling was 47 minutes.

[0140] When encountering a pebble layer that causes drilling to stall, each hole needs to be lifted and flushed an average of 4 times, with each time taking 3 to 5 minutes.

[0141] During the grouting stage of silty soft soil, 5 out of 20 piles (25%) collapsed and 3 out of 20 piles (15%) were connected in series, which seriously affected the integrity of the piles and increased the post-treatment costs.

[0142] The above data fully demonstrates that the control law proposed in this invention achieves spontaneous and intelligent solutions for various hazardous conditions in vibratory compaction construction using only a single easily measurable variable. Furthermore, the volumetric differential design and modular assembly of the adjustable pneumatic shock absorber structure further enhance the system's reliability and adaptability, demonstrating outstanding technical effectiveness and engineering practical value.

[0143] Example 6

[0144] The tire bead is provided in two parts, with the first tire bead located above the second tire bead; the ratio of the volume of the inner cavity of the first tire bead to the volume of the inner cavity of the second tire bead is x, where 0.98≤x≤0.99.

[0145] When subjected to axial impact loads, the smaller first tire bead exhibits a greater rate of pressure change (the instantaneous gradient of pressure change within the tire bead cavity as its volume changes), providing faster dynamic response stiffness and significantly suppressing high-frequency vibration components. The larger second tire bead, on the other hand, provides more stable support and absorbs the majority of the impact energy. The volume ratio between the two is set between 0.98 and 0.99 to create a stiffness gradient, avoiding sudden stiffness changes during impacts and broadening the effective operating frequency band of the shock absorber.

[0146] Simulation analysis shows that when the volume ratio is 0.986, the vibration transmission rate of the shock absorber in the 10~25Hz frequency band is reduced by about 15% compared with the equal volume design, while the peak stress is reduced by about 8%.

[0147] 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. An adjustable pneumatic shock absorber, comprising an upper housing and a lower tube shaft coaxially arranged with the upper housing, wherein a buffer assembly is provided between the upper housing and the lower tube shaft, characterized in that: The buffer assembly includes multiple sets of tire bead rings, each with an open bead ring on its inner ring. The lower tube shaft includes a vertical tube body and a flange tube fixedly connected to the lower end of the vertical tube body. The outer wall of the vertical tube body is provided with a bead seat that matches the inner ring of the tire bead ring. The outer ring of the bead seat is provided with a bead groove that matches the bead ring of the tire bead ring. The tire bead ring is fitted over the bead seat, and the inner ring of the tire bead ring is sealed to the bead seat. The upper part of the vertical tube body is provided with a vent, and the outer wall of the vertical tube body is also provided with an air hole that communicates with the opening. The inner cavity of the tire bead ring is connected to the vent through the air hole. The upper shell includes multiple sets of shell unit groups for fitting the tire bead rings. Each shell unit group consists of two shell units. The shell unit is located outside the tire bead ring, and the structure inside the shell unit matches the structure outside the tire bead ring. Adjacent shell units are fixedly connected.

2. The adjustable pneumatic shock absorber according to claim 1, characterized in that, It also includes an external control system, in which the inner cavities of all tire rims are interconnected and form a common air chamber. The external control system includes a four-way control valve group, an air source, and a pressure relief valve. The four-way control valve group includes a four-way pipe fitting and solenoid valves installed at the four joints of the four-way pipe fitting. The common air chamber is connected to the first solenoid valve of the four-way control valve group, the air source is connected to the second solenoid valve of the four-way control valve group, and the pressure relief valve is connected to the third solenoid valve of the four-way control valve group.

3. An adjustable pneumatic shock absorber according to claim 2, characterized in that: The external control system also includes a pressure dynamic adjustment component for dynamically adjusting the air pressure inside the main air chamber. The pressure dynamic adjustment component includes a volumetric pneumatic conversion element and a vibration actuator for applying vibration to the volumetric pneumatic conversion element. The air chamber inside the volumetric pneumatic conversion element is connected to the fourth solenoid valve of the four-way control valve group; When the second and third solenoid valves of the four-way control valve group are both closed and the first and fourth solenoid valves of the four-way control valve group are both open, the vibration actuator applies vibration to the volumetric pneumatic converter element, causing dynamic changes in the air pressure of the air chamber and the total air chamber within the volumetric pneumatic converter element.

4. An adjustable pneumatic shock absorber according to claim 3, characterized in that: The volumetric pneumatic conversion element is a high-pressure airbag or an air spring, and the vibration actuator is a vibrator or an actuator.

5. An adjustable pneumatic shock absorber according to claim 1, characterized in that: The tire bead is provided in two parts, with the first tire bead located above the second tire bead; the ratio of the volume of the inner cavity of the first tire bead to the volume of the inner cavity of the second tire bead is x, where 0.98≤x≤0.

99.

6. An adjustable pneumatic shock absorber according to claim 1, characterized in that: The tire bead has retaining rings installed on its upper and lower sides.

7. Vibro-compaction equipment, including a vibro-compactor, said vibro-compactor comprising a vibro-compactor body and a guide rod, characterized in that: An adjustable pneumatic shock absorber as described in claims 1 to 6 is provided between the lower end of the guide rod and the upper end of the vibratory shock absorber body. The lower end of the guide rod is fixedly connected to the upper end of the upper housing, and the upper end of the vibratory shock absorber body is fixedly connected to the flange pipe. A high-pressure air pipe is provided inside the guide rod, and one end of the high-pressure air pipe is connected to the ventilation channel.

8. The vibratory compaction equipment according to claim 7, characterized in that, It also includes a control module, which comprises: The acceleration acquisition unit is used to obtain the vibration acceleration envelope amplitude A of the guide rod. n ; Control law algorithm execution unit; Sine wave generator; The vibration acceleration envelope amplitude A n The input control law algorithm execution unit executes the control law algorithm, and the formula for the control law algorithm is as follows: ； Where, θ n θ refers to the instantaneous phase angle accumulated by the sine wave generator at the nth control cycle. n+1 The instantaneous phase angle accumulated by the sine wave generator at the (n+1)th control cycle; P set δ is the preset reference pressure; δ is the amplitude of the micro-perturbation, which is the maximum amplitude of the sinusoidal perturbation component superimposed on the preset reference pressure; f0 is the fundamental frequency; α is the coupling coefficient; Δt is the control period; It is A n The previous historical value; The target air pressure P was calculated. n+1 ; Based on the target air pressure P n+1 The air pressure inside the main air chamber is adjusted by the air pressure dynamic adjustment component of the external control system.

9. The vibratory compaction equipment according to claim 8, characterized in that: When the vibration acceleration envelope amplitude A is within a sliding time window of length N control cycles... n When the difference between the maximum and minimum values ​​is less than a first preset threshold, the target air pressure P n+1 It is a sine wave with frequency f0 and amplitude δ; Where N is an integer greater than 1, and the first preset threshold is an empirical calibration value; or, When the vibration acceleration envelope amplitude A is within a sliding time window of length N control cycles... n When the difference between the maximum and minimum values ​​exceeds the second preset threshold, the product term... Increase the phase increment Deviation from 2πf0Δt, target air pressure P n+1 The waveform exhibits a sudden phase change, deviating from the sine wave with frequency f0; Where N is an integer greater than 1, and the second preset threshold is an empirical calibration value; or, When conditions one and two are satisfied within a sliding time window of length M control cycles: Condition 1: Vibration acceleration envelope amplitude A n The difference between the maximum and minimum values ​​exceeds the third preset threshold; Condition 2: Amplitude difference between adjacent periods n -A n-1 The number of times the positive and negative signs alternate exceeds the fourth preset threshold; The product term increases the phase increment between adjacent periods. The deviation Δε from 2πf0Δt n The positive and negative signs of the pressure change more than the fifth preset threshold number of times within the sliding time window, and the target air pressure P n+1 Within the sliding time window, the normalized power percentage at frequency f0 decreases to below the sixth preset threshold. Where M is an integer greater than 1, and the third, fourth, fifth and sixth preset thresholds are all empirical calibration values; or, Within a sliding time window of length L control cycles, the following conditions are met: Condition 1: Vibration acceleration envelope amplitude A n The difference between the maximum and minimum values ​​is greater than the seventh preset threshold. Condition 2: Condition 1 is true for K consecutive sliding time windows, and then a sliding time window appears where Condition 1 is not true. Condition 3: The process of Condition 2 is repeated at least R times within the preset total observation time, and the fluctuation range of the number of sliding time windows between two adjacent initial sliding time windows that satisfy Condition 1 does not exceed ±T%. but: Target air pressure P within the sliding time window n+1 The maximum deviation between the instantaneous frequency of the waveform and f0 exceeds the eighth preset threshold. Target air pressure P n+1 The amplitude of the sliding envelope of the waveform and the amplitude of the vibration acceleration envelope A n The correlation coefficient exceeds the ninth preset threshold; Where L, K, and R are integers greater than 1, T is the preset percentage tolerance, and the seventh, eighth, and ninth preset thresholds are all empirical calibration values.

10. Vibro-compaction construction process, wherein the vibro-compaction construction equipment as described in any one of claims 7 to 9 is used for construction, characterized in that; Vibratory compactors are used for hole making and compaction construction.

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