Construction device and construction method of cement-soil compaction pile in loess tunnel

Abstract

The present application relates to the field of engineering construction technology, in order to solve the poor adaptability of existing loess tunnel compaction pile construction, the ramming effect is not good and the construction quality is difficult to control dynamically, a loess tunnel cement soil compaction pile construction device is provided, which comprises: a rammer body, comprising a slidingly connected upper hammer body and lower hammer body; A connecting seat is arranged above the upper hammer body, and a mounting cavity is formed in the connecting seat; The exhaust anti-blocking structure is vertically arranged in the rammer body; The noise reduction and mud removal structure is arranged in the upper hammer body, which is matched to buffer and reduce noise when hammering, and automatically blow off the accumulated mud on the upper end of the lower hammer body when lifting the hammer; The anti-rebound tamping structure is slidingly arranged on the periphery of the upper hammer body. The present application can realize the comprehensive construction effect of pile hole exhaust anti-blocking, hammering buffer and noise reduction, automatic mud cleaning and impurity removal, air pressure offsetting hammering rebound, tamping efficiency increasing, quality improving and real-time quantitative monitoring of construction quality.

Description

Technical Field

[0001] This invention relates to the field of engineering construction technology, specifically to a cement-soil compaction pile construction device and method for loess tunnels. Background Technology

[0002] In the construction of loess tunnels, loess possesses unique engineering geological characteristics such as a high natural porosity, loose structure, low shear strength, significant water collapseability, and easy compression deformation under stress. To effectively improve the overall bearing capacity of the tunnel foundation and surrounding rock, control subsequent tunnel settlement and deformation, and avoid engineering defects such as lining cracking and uneven foundation settlement induced by loess collapse, cement-soil compaction pile foundation reinforcement technology is typically used to compact and reinforce the soft soil at the tunnel bottom and surrounding areas of loess tunnels. Cement-soil compaction piles, through hammering and compaction, force the backfilled cement-soil in the pile hole to be compacted and consolidated with the surrounding undisturbed loess soil, forming a composite foundation bearing system with strong integrity, high bearing capacity, and small settlement deformation.

[0003] The traditional tamping equipment used in the construction of cement-soil compaction piles for loess tunnels is mostly a solid, integral tamping hammer structure, which has revealed many defects during construction: First, in existing integral tamping hammer operations, the air inside the pile hole cannot be quickly and effectively discharged, which easily forms a closed and stagnant air resistance. The air pressure generates a continuous upward reverse force on the tamping hammer, which greatly offsets the effective impact energy of the hammering and compaction, resulting in poor compaction and density of the pile body and uneven pile density.

[0004] Secondly, the tunnel interior is a confined construction space. The existing tamping hammer operation causes severe impact vibrations and construction noise that is difficult to accumulate and disperse, resulting in serious noise pollution in the working environment. This not only endangers the occupational health of on-site construction workers but also easily causes vibration disturbances to the initial support structure of the tunnel, posing a construction safety hazard.

[0005] Third, the existing tamping hammer has a large rigid impact rebound force during the hammering operation. The tamping hammer repeatedly bounces and deviates, which not only causes a large amount of hammering energy to be wasted ineffectively, but also easily causes the hammer body to deviate and hit the pile hole wall, resulting in quality problems such as the collapse of the loess hole wall and the displacement of the pile position.

[0006] Fourth, the existing cement-soil compaction piles rely solely on the subjective judgment of the construction personnel regarding the termination conditions of compaction, making it impossible to quantitatively control the compaction density of the pile body. The hammering data cannot be traced in real time, which can easily lead to quality problems such as under-compaction, over-compaction, or localized substandard compaction.

[0007] Therefore, there is an urgent need for a new type of cement-soil compaction pile construction device and method in loess tunnels to solve the above-mentioned technical problems existing in the current technology. Summary of the Invention

[0008] To address the aforementioned problems, this invention aims to provide a construction device and method for cement-soil compaction piles in loess tunnels, which can achieve comprehensive construction effects such as pile hole venting and anti-blocking, hammering buffering and noise reduction, automatic mud and impurity removal, air pressure to offset hammering rebound, compaction efficiency improvement and quality enhancement, and real-time quantitative monitoring of construction quality.

[0009] The main idea of ​​the technical solution adopted in this invention is as follows: By setting up a split, relatively sliding upper and lower hammer body, combined with an exhaust and anti-blockage structure, a noise reduction and mud removal structure, an anti-rebound and tamping aid structure, and a real-time monitoring component, the invention utilizes the air pressure linkage effect generated by the vertical relative sliding of the upper and lower hammer bodies to achieve multiple functions, including rapid conduction and exhaust of pressurized air inside the pile hole, damping and noise reduction of hammer vibration, automatic mud removal and impurity removal when lifting the hammer, and air pressure pushing against the hole wall to offset the hammer rebound force. At the same time, relying on an acceleration sensor and a wireless transmission module to collect hammer acceleration data in real time, the compaction degree of the pile body is dynamically determined by the change law of impact acceleration, realizing online quality monitoring of the entire tamping operation process, and significantly improving the pile formation quality and construction efficiency of cement-soil compaction piles in loess tunnels.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This application provides a cement-soil compaction pile construction device for loess tunnels, comprising: The tamping hammer body includes an upper hammer body and a lower hammer body that are slidably connected; A connecting seat is located above the upper hammer body, and an installation cavity is provided inside it; The exhaust and anti-blockage structure is vertically arranged inside the hammer body and is designed to quickly expel air from inside the pile hole during hammering operations. The noise reduction and mud removal structure is installed inside the upper hammer body. It is configured to buffer and reduce noise during hammering and automatically blow away the mud accumulated on the upper surface of the lower hammer body when the hammer is lifted. The anti-rebound tamping aid structure is slidably arranged on the outer periphery of the upper hammer body. It is configured to generate a reverse support force by pushing the inner wall of the pile hole with gas pressure to counteract the impact rebound force of the hammer.

[0011] Furthermore, based on the above technical solutions, the exhaust anti-clogging structure includes: The first exhaust channel is vertically opened through the periphery of the lower hammer body; The unblocking rod is located at the bottom of the upper hammer body and is vertically slidably inserted into the first exhaust channel; The second exhaust channel is located around the dredging rod and extends through to the top of the upper hammer body, connecting with the outside atmosphere.

[0012] Furthermore, based on the above technical solutions, the noise reduction and sludge removal structure includes: The linkage cavity is vertically opened on the inner side of the middle part of the upper hammer body; The piston plate is slidably disposed inside the linkage cavity, and the linkage cavity is divided into an upper cavity and a lower cavity by the piston plate; The linkage rod is located in the middle of the lower hammer body and extends upward to be fixedly connected to the piston plate; The soundproof airbag is mounted on the connecting seat and connected to the upper cavity through a connecting tube. The blowing holes are evenly distributed at the bottom of the lower cavity and extend through to the bottom of the upper hammer body to connect with the outside atmosphere.

[0013] Furthermore, based on the above technical solutions, the anti-rebound tamping aid structure includes: A receiving cavity is formed on the periphery of the upper hammer body, and an installation groove is provided thereon; The inclined push plate is slidably assembled inside the receiving cavity; The push rod is fixedly connected to the inclined push plate at one end, and the other end passes through the mounting groove to connect to the limit plate. The elastic element is sleeved on the outside of the section of the push rod inside the mounting groove; The push plate channel is located inside the upper hammer body. One end is connected to the receiving cavity, and the other end extends through to the bottom of the upper hammer body and is connected to the outside atmosphere.

[0014] Furthermore, the mounting cavity is equipped with an acceleration sensor and a wireless transmission module, and the two are electrically connected.

[0015] Furthermore, the connecting seat is provided with a connecting rod in the middle, and a connecting hole is provided on it, which is used to cooperate with external lifting equipment to realize the hoisting of the whole device.

[0016] Furthermore, through the above technical solution, the lower part of the upper hammer body is conical.

[0017] This application also provides a method for constructing cement-soil compaction piles in loess tunnels, including the following steps: Step 1: Connect and fix the construction device to the external lifting and compaction equipment through the connection holes to complete the hoisting and assembly; Step 2: Backfill the cement-soil mixture into the formed pile hole in layers, while driving the hammer body to fall and hammer. The upper and lower hammer bodies slide and squeeze relative to each other, and the high-pressure air in the pile hole is quickly discharged through the first exhaust channel and the second exhaust channel. The clearing rod slides back and forth to automatically clear the debris in the channel. Step 3: During the hammering process, the piston plate moves upward to compress the gas in the upper cavity and fills the sound-insulating airbag to achieve buffering and noise reduction. At the same time, the high-pressure gas pushes the inclined push plate to press against the inner wall of the pile hole, offsetting the hammering rebound force. Step 4: When the hammer is lifted and reset, the high-pressure airflow in the lower chamber is ejected from the cleaning hole, which automatically cleans the mud and residue accumulated on the upper end of the lower hammer body, and the inclined push plate elastically retracts and resets. Step 5: The accelerometer collects impact acceleration data in real time and transmits it to the monitoring terminal. The compactness of the pile body is determined based on the acceleration change pattern. Step 6: After the standard is met, move to the next pile location and repeat steps 2 to 5 until all compaction pile construction work is completed.

[0018] The beneficial effects of this invention are: 1. This invention features a split sliding upper and lower hammer body, combined with an exhaust and anti-blocking structure. The relative sliding of the upper and lower hammer bodies allows for rapid drainage of compressed air inside the pile hole during hammering operations, preventing air resistance caused by the sealed air pressure. Simultaneously, the draining rod reciprocates within the exhaust channel, automatically clearing accumulated mud, cement residue, and other debris in real time, achieving continuous exhaust and automatic anti-blocking.

[0019] 2. This invention, by setting up a noise reduction and mud removal structure, relies on the linkage and sliding of the upper and lower hammers to form air pressure changes. During the hammering stage, sound-insulating airbags are used to absorb impact vibrations and block noise transmission, effectively reducing noise pollution in the confined space of the tunnel. During the hammer lifting stage, high-pressure airflow is used to automatically blow away the mud and debris accumulated on the upper part of the lower hammer, eliminating the need for manual shutdown for cleaning, and greatly improving the continuity of construction and work efficiency.

[0020] 3. This invention sets up an anti-rebound tamping structure, which uses the internal high-pressure gas generated by the hammer to drive the inclined push plate to press against the inner wall of the pile hole. The reverse support force of the hole wall offsets the impact rebound force of the hammer, reduces the bouncing and shaking of the hammer body, and reduces the impact energy loss. At the same time, the principle of inclined force decomposition is used to enhance the downward compaction effect, which significantly improves the compaction effect of cement soil and loess between piles.

[0021] 4. This invention uses an acceleration sensor and a wireless transmission module to collect and remotely transmit hammer impact acceleration data in real time. By relying on the acceleration change pattern, it can accurately determine the pile compaction and construction anomalies, realize real-time dynamic monitoring of compaction quality, and make construction quality more controllable.

[0022] 5. This invention relies entirely on mechanical linkage and pneumatic adaptive drive, requiring no additional power equipment. It has low energy consumption, strong adaptability, and can be directly adapted to the narrow working space of tunnels, making it highly practical and valuable for engineering applications and promotion. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 For the present invention Figure 1 First cross-sectional view; Figure 3 This is a cross-sectional schematic diagram of the hammer body of the present invention when the hammer is lifted; Figure 4 This is a cross-sectional schematic diagram of the hammer body of the present invention during hammering; Figure 5 This is a schematic diagram of the hammer body structure of the present invention; Figure 6 This is a schematic diagram of the inverted hammer structure of the present invention; Figure 7 This is a schematic diagram showing the positional relationship of the anti-rebound tamping aid structure of the present invention; Figure 8 For the present invention Figure 7 Enlarged view of point A; Figure 9 This is a schematic diagram of the connector structure of the present invention; Figure 10 This is a schematic diagram showing the connection relationship between the connector and the soundproof airbag of the present invention; Figure 11 This is a schematic diagram of the hammer body structure of the present invention; Figure 12 For the present invention Figure 11 Cross-sectional view; Figure 13 This is a schematic diagram illustrating the application scenario of the cement-soil compaction pile construction device for loess tunnels according to the present invention.

[0024] The components include: 1. Upper hammer body; 2. Lower hammer body; 3. Connecting seat; 31. Mounting cavity; 32. Connecting rod; 321. Connecting hole; 4. Exhaust anti-blocking structure; 41. First exhaust channel; 42. Unblocking rod; 43. Second exhaust channel; 5. Noise reduction and mud cleaning structure; 51. Linkage cavity; 511. Upper cavity; 512. Lower cavity; 52. Piston plate; 53. Linkage rod; 54. Sound insulation airbag; 541. Connecting pipe; 55. Cleaning hole; 6. Anti-rebound tamping structure; 61. Receiving cavity; 611. Mounting groove; 62. Inclined push plate; 63. Push rod; 64. Limiting plate; 65. Elastic element; 66. Push plate channel; 7. Accelerometer; 8. Wireless transmission module. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] The inventors discovered that existing tamping hammers have a simple structure and limited functions. When constructing in the narrow and confined environment of loess tunnels, they generally suffer from problems such as poor ventilation in the pile hole, easy pressure buildup and blockage, large hammer rebound, high energy loss during compaction, easy adhesion of mud to the tamping hammer, concentrated noise during tunnel operations, and inability to detect the density of the pile body in real time. They are difficult to adapt to the special working conditions of loess soil that is loose and prone to collapse and waterlogging, making it difficult to guarantee the quality of pile formation and construction efficiency.

[0027] Based on the above findings, this application proposes a construction device and method for cement-soil compaction piles in loess tunnels. It adopts a split sliding hammer body, which integrates the functions of air exhaust and anti-blockage, noise reduction and mud removal, anti-rebound and tamping assistance, and real-time monitoring. It relies on mechanical linkage and air pressure adaptive collaborative work to specifically solve the defects of existing technologies and meet the high-quality and continuous construction requirements of compaction piles in loess tunnels. Example

[0028] See Figures 1-13 This application discloses a cement-soil compaction pile construction device for loess tunnels, which is suitable for construction pain points such as narrow working space, loose and easily collapsed soil, easy water-induced subsidence of loess, noise accumulation in the confined tunnel space, poor ventilation and easy blockage of pile holes, and difficulty in controlling the compaction density of the pile body. It includes a tamping hammer body, a connecting seat 3, a ventilation and anti-blocking structure 4, a noise reduction and mud-clearing structure 5, and an anti-rebound tamping aid structure 6.

[0029] The tamping hammer adopts a split structure, including an upper hammer 1 and a lower hammer 2 that are coaxially slidably connected, and the two can undergo relative reciprocating sliding displacement along the vertical direction. The lower part of the upper hammer 1 has a conical structure, and the outer diameter of the lower hammer 2 is consistent with the minimum diameter of the conical structure of the upper hammer 1. Both have a pre-reserved annular air gap between them and the pile hole wall. During the tamping operation, some of the compressed air inside the pile hole can flow smoothly and release pressure through this annular gap, effectively preventing the air inside the pile hole from being continuously compressed and forming air pressure resistance, preventing the air pressure from generating an upward reverse pushing force on the tamping hammer, and eliminating the loss of tamping energy.

[0030] The connecting seat 3 is fixedly mounted on the top of the upper hammer body 1 by bolts. The connecting seat 3 has an integrally formed installation cavity 31. A connecting rod 32 is integrally fixed in the middle of the installation cavity 31. A connecting hole 321 is formed at the top of the connecting rod 32, which is used to cooperate with external lifting and compaction equipment such as tamping machines to complete the hoisting, hanging and lifting traction operation of the entire hammer body.

[0031] Next, the exhaust anti-blocking structure 4 is vertically arranged inside the tamping hammer body. It is used to quickly guide and discharge the pressurized air inside the pile hole during the hammering operation, avoiding the impact of air pressure buildup inside the pile hole on the compaction effect. At the same time, it realizes automatic unblocking and anti-blocking during the operation, preventing soil from blocking the exhaust channel and affecting the exhaust operation. It includes a first exhaust channel 41, an unblocking rod 42, and a second exhaust channel 43.

[0032] Specifically, the first exhaust channel 41 is provided in multiple ways, preferably three in this embodiment, which are vertically opened inside the two sides of the lower hammer body. It should be noted that the first exhaust channel 41 includes a small diameter section and a large diameter section.

[0033] Multiple unblocking rods 42 are provided, preferably three in this embodiment, each corresponding to one of the first exhaust channels 41. The unblocking rods 42 are fixedly installed on the bottom periphery of the upper hammer body 1 and vertically slide into the first exhaust channel 41, with a pre-set gap between them. During the relative sliding process of the upper hammer body 1 and the lower hammer body 2, the unblocking rods 42 can slide back and forth along the inside of the first exhaust channel 41 to automatically unblock the silt inside the channel in real time, preventing the exhaust channel from being blocked by mud, ash, or cement.

[0034] Multiple sets of the second exhaust channels 43 are provided, preferably three sets in this embodiment, corresponding to each unblocking rod 42, with three channels in each set. The three second exhaust channels 43 are opened around the unblocking rod 42, with one end connected to the large-diameter section of the first exhaust channel 41, and the other end extending vertically to the top of the upper hammer body 1 and connecting with the outside atmosphere, forming a vertical exhaust path from the inside of the pile hole to the first exhaust channel 41 to the second exhaust channel 43 to the outside atmosphere. During the hammering and pressing process, the pressurized air inside the pile hole can be quickly and smoothly discharged without pressure buildup or pipe blockage.

[0035] The noise reduction and sludge removal structure 5 is installed inside the upper hammer body 1. It achieves air pressure linkage operation by relying on the relative sliding of the upper and lower hammer bodies. During the hammering operation, it reduces noise. During the hammer lifting and resetting operation, it automatically uses air pressure to blow away the loess, cement mud, and debris accumulated on the upper surface of the lower hammer body 2. It includes a linkage cavity 51, a piston plate 52, a linkage rod 53, a sound insulation airbag 54, and a cleaning hole 55.

[0036] Specifically, the linkage cavity 51 is vertically opened at the inner side of the middle part of the upper hammer body 1, and the piston plate 52 is slidably disposed inside the linkage cavity 51. The outer edge of the piston plate 52 is sealed and slidably attached to the inner wall of the linkage cavity 51, and the piston plate 52 seals and divides the internal space of the linkage cavity 51 into an independent upper cavity 511 and a lower cavity 512.

[0037] The linkage rod 53 is fixedly installed at the top center of the lower hammer body 2. The linkage rod 53 extends vertically through the upper hammer body 1 and is fixedly connected to the bottom end face of the piston plate 52. When the lower hammer body 2 slides vertically relative to the upper hammer body 1, the piston plate 52 can be driven to slide up and down inside the linkage cavity 51 in a synchronous manner through the linkage rod 53, so as to realize the synchronous change of air pressure inside the upper and lower cavities.

[0038] The soundproof airbag 54 is preferably made of fabric-reinforced explosion-proof nitrile rubber composite material through integral vulcanization, with an internal nylon fiber mesh reinforcement structure. It is bolted to the connecting seat 3 in a ring. The mounting cavity 31 is provided with a connecting pipe 541. One end of the connecting pipe 541 is connected to the soundproof airbag 54, and the other end is connected to the upper cavity 511. That is, the soundproof airbag 54 is connected to the interior of the upper cavity 511 through the connecting pipe 541. During the hammering operation, the piston plate 52 moves upward to compress the gas inside the upper cavity 511. The high-pressure gas is introduced into the soundproof airbag 54 through the connecting pipe 541. The airbag absorbs the hammering vibration energy by relying on its flexible buffer deformation, and it can also block the air transmission of sound by relying on the sealed air layer, thus simultaneously reducing the construction noise generated by the hammering operation.

[0039] Multiple cleaning holes 55 are provided, which are evenly arranged in a ring at the bottom of the lower cavity 512. One end of the cleaning hole 55 is connected to the lower cavity 512, and the other end extends vertically to the bottom end face of the upper hammer body 1 and is connected to the outside atmosphere. When the hammer is lifted, the piston plate 52 moves down and squeezes the gas inside the lower cavity 512. The high-pressure airflow is concentrated and sprayed out through each cleaning hole 55, automatically blowing away the mud and cement residue accumulated on the upper end face of the lower hammer body 2, realizing the automated operation of mud cleaning and impurity removal.

[0040] Next, the anti-rebound tamping assist structure 6 is slidably positioned on the outer periphery of the upper hammer body 1. It generates a reverse supporting force by pushing against the inner wall of the pile hole through gas pressure, offsetting the impact rebound force generated during the hammering operation and reducing hammering energy loss. It should be noted that both the anti-rebound tamping assist structure 6 and the exhaust anti-blockage structure 4 adopt a triangular arrangement, and the two types of structures are arranged alternately along the circumference of the hammer body, resulting in a compact and reasonable overall layout where movement and airflow do not interfere with each other.

[0041] The anti-rebound tamping structure 6 includes a receiving cavity 61, an inclined push plate 62, a push rod 63, a limiting plate 64, an elastic element 65, and a push plate channel 66.

[0042] Specifically, the receiving cavity 61 is provided in multiple ways, preferably three in this embodiment, and is evenly circumferentially opened around the upper hammer body. A mounting groove 611 is correspondingly opened on the side of the receiving cavity 61 closest to the axis. The inclined push plate 62 is slidably assembled inside the receiving cavity 61 and can slide back and forth along the cavity. One end of the push rod 63 is fixedly connected to the inclined push plate 62, and the other end passes through the mounting groove 611 and is fixedly connected to a limiting plate 64. The outer diameter of the limiting plate 64 is larger than the outer diameter of the push rod 63, used to limit and stop the sliding stroke, preventing the push rod from sliding back. The rod disengages from the mounting groove 611; the elastic element 65 is a spring, sleeved on the outer side of the section of the push rod 63 inside the mounting groove 611, one end is fixedly connected to the inner wall of the mounting groove 611, and the other end is fixedly connected to the limiting plate 64. Under normal conditions, the inclined push plate 62 is reset and retracted by the elastic push of the elastic element 65. The push plate channel 66 is opened inside the upper hammer body 1. One end of the push plate channel 66 is connected to the inside of the receiving cavity 61, and the other end extends vertically to the bottom of the upper hammer body 1 and is connected to the outside atmosphere.

[0043] It should be noted that, under normal conditions, the inclined push plate 62 and the receiving cavity 61 form a sealed cavity. During the hammering and compaction operation, the upper hammer 1 and the lower hammer 2 are squeezed against each other, forming high-pressure gas between the two hammers. This high-pressure gas can be introduced into the receiving cavity 61 through the push plate channel 66. The inclined push plate 62 is inclined upwards, and the introduced high-pressure gas overcomes the elastic clamping force of the elastic element 65, pushing the inclined push plate 62 outwards and tightly squeezing against the soil wall of the pile hole. Relying on the inclined plate structure of the inclined push plate 62, the reverse force applied by the soil wall is decomposed downwards, which can effectively offset the vertical rebound torque of the upper hammer 1 at the moment of contact between the two hammers, reduce the hammering rebound phenomenon, avoid the loss and waste of impact energy, and at the same time convert the high-pressure air pressure between the two hammers into the downward hammering gain of the upper hammer, further improving the compaction effect. The elastic element 65 expands and contracts synchronously with the increase and decrease of air pressure in the cavity, realizing the sliding adaptation and automatic reset of the inclined push plate 62 after depressurization.

[0044] Furthermore, an acceleration sensor 7 and a wireless transmission module 8 are fixedly installed inside the mounting cavity 31. The cavity is sealed and isolated from the soil and rock. The acceleration sensor 7 and the wireless transmission module 8 are electrically connected. During the operation, the acceleration sensor 7 collects the impact acceleration waveform during the hammering and compaction process in real time and transmits it remotely to an external monitoring terminal in real time through the wireless transmission module 8. By analyzing the maximum acceleration change law of the acceleration waveform, the construction personnel can judge the compaction status of the pile body, thereby dynamically grasping the compaction density of the pile body and construction anomalies, and realizing real-time monitoring and control of construction quality.

[0045] It should be noted that the accelerometer 7 collects the impact acceleration of the upper hammer 1 at the moment of impact between the upper hammer 1 and the lower hammer 2. During continuous tamping, as the pile and the surrounding loess are continuously compacted, the overall stiffness and support strength of the soil gradually increase, and the impact feedback force of the upper and lower hammers continues to increase, with the corresponding maximum impact acceleration steadily increasing with each impact. When the maximum acceleration value obtained from multiple hammer impacts tends to stabilize and no longer increases significantly, it indicates that the compression deformation of the pile soil is basically completed, and the compaction density of the pile has reached the design and construction standards. If the maximum acceleration value suddenly drops abnormally during the hammering process, it indicates that there are abnormal construction conditions such as voids, soft interlayers, tamping voids, or soil disturbance and loosening inside the pile. Work must be stopped on-site in a timely manner for investigation and rectification. Tamping can only continue after confirming that there are no quality hazards. Application Examples

[0046] This application example is mainly applicable to specific construction scenarios of cement-soil compaction piles, such as surrounding rock reinforcement of loess tunnels, foundation treatment, and soft soil replacement at the tunnel bottom. The specific application process is as follows: 1. Hoisting and assembly in the early stage of construction First, the surveying and setting out of the pile holes in the loess tunnel, the drilling and cleaning of the hole are completed. Then, the cement-soil compaction pile construction device described in this application is connected and fixed to the hoisting structure of the compaction machine through the connecting hole 321.

[0047] 2. Hammering and compaction operation The control unit drives the tamping hammer to fall and hammer. The upper hammer 1 and the lower hammer 2 slide and press against each other vertically under the action of gravity, entering the tamping and compaction state. During the hammering process, part of the compressed air inside the pile hole is quickly released through the annular gap around the tamping hammer, and the other part forms a vertical through-flow exhaust path through the first exhaust channel 41 and the second exhaust channel 43 of the exhaust and anti-blocking structure 4, quickly expelling the high-pressure gas inside the pile hole. At the same time, the unblocking rod 42 slides back and forth with the upper hammer 1, automatically unblocking the exhaust channel in real time to prevent soil from accumulating and blocking the hole.

[0048] Simultaneously, the relative sliding of the upper and lower hammers drives the linkage rod 53 to pull the piston plate 52 upward within the linkage cavity 51, compressing the gas in the upper cavity 511. The high-pressure gas is introduced into the sound-insulating airbag 54 through the connecting pipe 541. The flexible deformation of the airbag absorbs the hammer vibration energy and blocks construction noise, achieving buffering and noise reduction during hammering. The high-pressure gas formed by the compression between the two hammers is introduced into the receiving cavity 61 of the anti-rebound tamping structure 6 through the push plate channel 66. The high-pressure gas overcomes the elastic force of the elastic element 65 and pushes the inclined push plate 62 outward to press against the wall of the pile hole, thereby effectively offsetting the vertical hammering rebound force of the upper hammer 1, reducing the ineffective loss of hammering energy, and at the same time converting the air pressure into a hammering downward pressure gain effect, improving the compaction effect of the cement-soil compaction pile.

[0049] 3. Automatic pneumatic sludge removal during the hammer lifting and resetting stage. After a single hammer blow is completed, the tamping machine is controlled to lift the hammer upwards, causing the upper and lower hammer bodies to slide in opposite directions. The piston plate 52 descends inside the linkage chamber 51, compressing the gas inside the lower chamber 512. The high-pressure airflow in the lower chamber 512 is concentrated and ejected at high speed through the cleaning hole 55 at the bottom, automatically blowing away the accumulated loess, cement slurry, and debris adhering to the upper surface of the lower hammer body 2. This achieves automatic cleaning of the hammer body's working surface, preventing soil accumulation from affecting the subsequent hammer blow's adhesion accuracy and compaction effect. During the hammer lifting and depressurization process, the air pressure inside the anti-rebound tamping aid structure 6 drops synchronously, and the inclined push plate 62 automatically retracts and resets under the pull of the elastic element 65. The entire structure returns to its initial normal position, ready for the next hammer blow.

[0050] 4. Strengthen real-time data monitoring During each hammering operation, the accelerometer 7 inside the mounting cavity 31 collects the impact acceleration data of the upper and lower hammers at the moment of impact in real time, and transmits it remotely to the external construction monitoring terminal via the wireless transmission module 8. As the repeated hammering and compaction operation progresses, the construction personnel determine the compaction status of the pile by analyzing the maximum acceleration change pattern of the acceleration waveform.

[0051] 5. Once the pile is completed and relocated, proceed to the next pile location for cyclical construction. After the compaction density of a single cement-soil compaction pile meets the standard, the entire construction device is lifted and moved out of the pile hole by a tamping machine. After simple protection treatment of the pile opening, the device is moved to the next designed pile position, and the above construction process is repeated to complete the standardized cyclic construction operation of all cement-soil compaction piles in the loess tunnel area.

[0052] The basic principles, main features, and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cement-soil compaction pile construction device for loess tunnels, characterized in that, include: The hammer body includes an upper hammer body (1) and a lower hammer body (2) that are slidably connected. The connecting seat (3) is located above the upper hammer body (1), and an installation cavity (31) is provided inside it. The exhaust and anti-blocking structure (4) is arranged vertically inside the hammer body and is configured to quickly exhaust the air inside the pile hole during hammering operations. The noise reduction and mud removal structure (5) is installed inside the upper hammer body (1) and is configured to buffer and reduce noise when hammering and automatically blow away the accumulated mud on the upper surface of the lower hammer body (2) when the hammer is lifted. The anti-rebound tamping structure (6) is slidably arranged on the outer periphery of the upper hammer body (1) and is configured to generate a reverse support force by pushing the inner wall of the pile hole with gas pressure to offset the impact rebound force of the hammer.

2. The cement-soil compaction pile construction device for loess tunnels according to claim 1, characterized in that, The exhaust anti-clogging structure (4) includes: The first exhaust channel (41) is vertically opened through the side of the lower hammer body (2); The unblocking rod (42) is set at the bottom of the upper hammer body (1) and is vertically slidably inserted into the first exhaust channel (41); The second exhaust channel (43) is located around the dredging rod (42) and extends through to the top of the upper hammer (1) to connect with the outside atmosphere.

3. The cement-soil compaction pile construction device for loess tunnels according to claim 2, characterized in that, The noise reduction and sludge removal structure (5) includes: The linkage cavity (51) is vertically opened on the inner side of the middle part of the upper hammer body (1); The piston plate (52) is slidably disposed inside the linkage cavity (51), and the linkage cavity (51) is divided into an upper cavity (511) and a lower cavity (512) by the piston plate (52). Linkage rod (53) is located in the middle of the lower hammer body (2) and extends upward to be fixedly connected to piston plate (52); The soundproof airbag (54) is mounted on the connecting seat (3) and connected to the upper cavity (511) through the connecting pipe (541); The blowing holes (55) are evenly distributed at the bottom of the lower cavity (512) and extend through to the bottom of the upper hammer (1) to connect with the outside atmosphere.

4. The cement-soil compaction pile construction device for loess tunnels according to claim 3, characterized in that, The anti-rebound tamping structure (6) includes: A receiving cavity (61) is opened on the periphery of the upper hammer body (1), and an installation groove (611) is provided thereon. The inclined push plate (62) is slidably assembled inside the receiving cavity (61); The push rod (63) is fixedly connected at one end to the inclined push plate (62), and the other end passes through the mounting groove (611) to connect to the limit plate (64). The elastic element (65) is sleeved on the outside of the section of the push rod (63) located inside the mounting groove (611); The push plate channel (66) is located inside the upper hammer body (1), with one end connected to the receiving cavity (61) and the other end extending through to the bottom of the upper hammer body (1) and connected to the outside atmosphere.

5. A cement-soil compaction pile construction device for loess tunnels according to claim 4, characterized in that, The mounting cavity (31) is equipped with an acceleration sensor (7) and a wireless transmission module (8), and the two are electrically connected.

6. A cement-soil compaction pile construction device for loess tunnels according to claim 5, characterized in that, A connecting rod (32) is provided in the middle of the connecting seat (3), and a connecting hole (321) is provided on it.

7. A cement-soil compaction pile construction device for loess tunnels according to claim 6, characterized in that, The lower part of the upper hammer (1) is conical.

8. A method for constructing cement-soil compaction piles in loess tunnels, characterized in that, Includes the following steps: Step 1: Connect and fix the construction device to the external lifting and compaction equipment through the connection hole (321) to complete the hoisting and assembly; Step 2: Backfill the cement-soil mixture into the formed pile hole in layers, while driving the hammer body to fall and hammer. The upper hammer body (1) and the lower hammer body (2) slide and squeeze relative to each other. The high-pressure air in the pile hole is quickly discharged through the first exhaust channel (41) and the second exhaust channel (43). The dredging rod (42) slides back and forth to automatically dredge the debris in the channel. Step 3: During the hammering process, the piston plate (52) moves upward to compress the gas in the upper cavity 511 and fills the sound insulation airbag (54) to achieve buffering and noise reduction. At the same time, the high-pressure gas pushes the inclined push plate (62) to press against the inner wall of the pile hole to offset the hammering rebound force. Step 4: When the hammer is reset, the high-pressure airflow in the lower cavity (512) is ejected from the cleaning hole (55) to automatically clean the mud and residue accumulated on the upper end of the lower hammer body (2), and the inclined push plate (62) elastically retracts and resets. Step 5: The accelerometer (7) collects impact acceleration data in real time and transmits it to the monitoring terminal. The compactness of the pile body is determined according to the acceleration change law. Step 6: After the standard is met, move to the next pile location and repeat steps 2 to 5 until all compaction pile construction work is completed.

Images