A soft soil vibro-replacement stone pile top reinforcing device and method

Abstract

This invention discloses a device and method for reinforcing the top of vibratory compaction stone piles in soft soil. The device includes a positioning device and a grouting pipe. The positioning device consists of two assembleable rings. The inner ring has a hole diameter larger than the vibratory compactor diameter but smaller than the pile diameter, serving as a channel for the vibratory compactor to fall. The outer ring has a diameter larger than the intended pile diameter and can be stably positioned around the pile hole on the ground. Grouting pipe installation holes are symmetrically arranged around the inner ring for installing the grouting pipe. This device can be used in conjunction with conventional construction equipment such as vibratory compactors. After the hole is formed, the positioning device is set on the ground to fix the position and depth of the grouting pipe. Grouting begins after the crushed stone is filled, with the pipe being pulled out while grouting, ensuring that the cement grout is evenly mixed with the crushed stone at the shallow part of the pile top, thus reinforcing the shallow part of the crushed stone pile that is prone to bulging and damage. This reinforcement method can greatly improve the overall strength of the vibratory compaction stone pile, while saving construction costs. The grouting pipe depth can be adjusted according to the project conditions, offering high flexibility.

Description

Technical Field

[0001] This invention relates to the field of civil engineering, and in particular to a device and method for reinforcing the top of a vibratory compaction stone pile in soft soil. Background Technology

[0002] Vibro-compacted stone piles are composite foundation reinforcement piles made primarily of crushed stone. They are widely used in soft soil foundation reinforcement, accelerating consolidation and drainage, and improving bearing capacity. However, as a type of granular material pile, the bearing capacity of vibro-compacted stone piles mainly comes from the restraining effect of the surrounding soil. In soft soil foundations, the soil quality is poor, and the restraining force provided by the surrounding soil to the stone pile is relatively small, easily causing damage to the stone pile. This is especially true when the pile length is large, making it difficult to apply stone piles in practical engineering.

[0003] Grouting reinforcement of crushed stone piles can effectively improve the overall strength of the pile body, increase the deformation modulus of the composite foundation, and reduce soil deformation. The existing construction process for crushed stone grouting piles involves embedding a grouting pipe after drilling, flushing the borehole with water during the stone placement process, and then performing grouting reinforcement after the stone placement is complete. While the traditional crushed stone pile grouting reinforcement process can solve the problem of easy damage to crushed stone piles in soft soil foundations and effectively improve the pile bearing capacity, it also has several drawbacks:

[0004] (1) Grouting reinforcement After the granular material piles are reinforced into cement-crushed stone mixed materials, the permeability coefficient decreases significantly, and the original advantage of the crushed stone piles in accelerating drainage and consolidation is lost.

[0005] (2) Studies have shown that under load, the upper part of the crushed stone pile bears greater stress, while the soil constraint in the shallow part is weaker. Therefore, the upper part of the pile is prone to large bulging deformation, which is not conducive to the bearing capacity of the crushed stone pile. The lower part of the pile has a relatively smaller impact on the bearing capacity. Therefore, the method of whole pile grouting reinforcement results in great waste and greatly increases the cost of a single pile.

[0006] (3) The existing reinforcement process for grout-stabilized crushed stone piles requires drilling first, which is not applicable to vibratory crushed stone piles. The drilling method is not as simple as the vibratory crushing method.

[0007] (4) The traditional construction process of crushed stone grouting piles involves grouting the entire pile. The required grouting pipe is very long and lacks positioning devices. During the filling and grouting process, the grouting pipe is prone to displacement, resulting in inaccurate grouting position.

[0008] (5) Traditional crushed stone grouting piles will be reinforced by "grouting and pipe pulling" to gradually move the grouting port upward. However, the pipe pulling process is cumbersome and complicated when the pile body is long and the grouting pipe is long, which is not convenient for construction operations.

[0009] In view of the above-mentioned shortcomings of traditional crushed stone grouting piles, a method and device for reinforcing the top of soft soil vibratory crushed stone piles are proposed to solve the existing problems and achieve the effects of reinforcing the pile body, saving economic costs, and protecting the environment. Summary of the Invention

[0010] The practical problem to be solved by this invention is to provide a method and device for reinforcing the top of vibratory compaction stone piles in soft soil, in order to solve the problem of insufficient bearing capacity of the shallow part of vibratory compaction stone piles in soft soil foundations, which leads to failure. Furthermore, this invention retains the advantages of stone piles in accelerating drainage and consolidation, reduces grouting volume to save economic costs, shortens construction time, and improves pile quality.

[0011] The technical solution adopted by the present invention to solve its technical problem is as follows: According to the first aspect of the specification, a soft soil vibratory compaction stone pile top reinforcement device is provided, the device comprising: a positioning device and a grouting pipe;

[0012] The positioning device consists of two assemblable semicircular rings, with mounting holes for the positioning device and grouting pipe on the rings. The mounting holes for the positioning device are used to install the positioning device on the ground, serving to fix and accurately position it. The outer ring diameter of the positioning device is larger than the pile hole diameter, and the distance from the mounting hole of the positioning device to the center of the ring is larger than the pile hole radius. The inner ring diameter of the positioning device is larger than the vibratory compactor diameter but smaller than the pile hole diameter, serving as a channel for the vibratory compactor to fall.

[0013] The grouting pipe passes through the grouting pipe installation hole to reinforce the top of the pile with grout.

[0014] Furthermore, in the positioning device, the two semicircular rings are connected by screws.

[0015] Furthermore, the positioning device is tightly fitted to the ground at the mounting hole of the positioning device by screws, which serves to fix and accurately position the device.

[0016] Furthermore, a rubber ring is attached to the inner side of the grouting pipe mounting hole for a tight connection between the grouting pipe and the positioning device.

[0017] According to a second aspect of this specification, a method for reinforcing the top of vibratory compaction stone piles in soft soil is provided, the method comprising the following steps:

[0018] Step 1: Clear and level the construction site, arrange the pile positions, and position the vibratory compactor and crane;

[0019] Step 2: Start the vibratory compactor, determine the water pressure and volume, and sink it into the soil until the bottom elevation of the pile is reached;

[0020] Step 3: After drilling, lift the vibratory compactor to the hole opening and flush it with water, then lower it to the bottom of the hole. Repeat this step to enlarge the hole diameter, clean the soil inside the hole, and prepare for pile making.

[0021] Step 4: Fill the hole with crushed stone and compact it by vibration during filling;

[0022] Step 5: When the crushed stone is filled to the elevation of the reinforced area, place the two semi-circular rings of the positioning device around the vibratory compactor, assemble the two semi-circular rings into one piece, and fix it on the ground; install the grouting pipe on the positioning device and lower it to the elevation of the reinforced area.

[0023] Step 6: Continue filling until filling is complete, then remove the vibratory compactor and crane;

[0024] Step 7: Start grouting, slowly and evenly pull up the grouting pipe to ensure that the cement grout and crushed stone are mixed evenly in the reinforced area; traditional crushed stone piles are prone to bulging failure within a depth range of 1 to 3 times the pile diameter at the top of the pile. In view of this situation, the depth of the reinforced area is conservatively taken as 5 times the pile diameter.

[0025] Step 8: Continue grouting to the borehole opening to complete the shallow crushed stone grouting reinforcement; at this point, the grouting reinforcement is complete and the single pile construction is finished.

[0026] Furthermore, during the grouting reinforcement and filling pile fabrication process, it is necessary to ensure that the positioning device is fully fixed to the ground and that the positioning is accurate.

[0027] Furthermore, the grouting process should be carried out at a uniform and slow speed, with multiple grouting pipes being pulled up simultaneously to ensure thorough mixing of the grout and aggregate.

[0028] The beneficial effects of this invention are:

[0029] (1) The present invention will specifically reinforce the shallow part of the vibratory crushed stone pile that is prone to bulging and damage, thereby avoiding the waste of resources caused by reinforcing the entire crushed stone pile and saving economic costs.

[0030] (2) This invention preserves the permeability of the lower part (unreinforced section) of the crushed stone pile while ensuring the bearing capacity of the vibratory crushed stone pile, which has a positive effect on accelerating the drainage and consolidation of soft soil foundation.

[0031] (3) This invention differs from traditional grout-stabilized crushed stone piles and is a method and device for reinforcing the top of vibratory crushed stone piles.

[0032] (4) The present invention includes a grouting pipe positioning device, which solves the problem of inaccurate position and depth of grouting pipe in traditional grouting process and improves grouting quality and efficiency.

[0033] (5) This invention differs from traditional grouting construction. The grouting pipe is short and located in a shallow position, which greatly reduces the difficulty of pipe pulling, simplifies the construction process, and is more in line with the needs of actual construction.

[0034] (6) This invention employs a movable device to adjust the grouting position of the crushed stone pile, which can be combined with different soil conditions and pile lengths to handle the intended reinforcement position. The length of the reinforcement section is determined according to the actual engineering situation, ensuring flexibility and reliability.

[0035] (7) All the equipment of the present invention, including the positioning device and the grouting pipe, can be recycled and reused multiple times. The installation is simple and the equipment production cost is low, taking into account the economic cost of on-site construction. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of the crushed stone pile after reinforcement by the method and device for reinforcing the top of the soft soil vibratory compaction crushed stone pile of the present invention.

[0037] Figure 2 This is a schematic diagram of the principle of the method and device for reinforcing the top of a soft soil vibratory compaction stone pile according to the present invention;

[0038] Figure 3 This is a schematic diagram of the positioning device in the method and apparatus for reinforcing the top of soft soil vibratory compaction stone piles of the present invention.

[0039] Figure 4 This is a schematic diagram of the positioning device and grouting pipe in the method and apparatus for reinforcing the top of a soft soil vibratory compaction stone pile of the present invention.

[0040] Figure 5 It is along Figure 1 Cross-sectional view of line AA in the middle;

[0041] Figure 6 It is along Figure 1 Cross-sectional view of the middle BB line;

[0042] Figure 7 This is a schematic diagram of step 1 of the construction method for shallow reinforcement of crushed stone piles using the soft soil vibratory compaction crushed stone pile top reinforcement method and device of the present invention;

[0043] Figure 8 This is a schematic diagram of step 2 of the construction method for shallow reinforcement of crushed stone piles using the soft soil vibratory compaction crushed stone pile top reinforcement method and device of the present invention;

[0044] Figure 9 This is a schematic diagram of step 4 of the construction method for shallow reinforcement of crushed stone piles using the soft soil vibratory compaction crushed stone pile top reinforcement method and device of the present invention;

[0045] Figure 10 This is a schematic diagram of step 5 of the construction method for shallow reinforcement of crushed stone piles using the soft soil vibratory compaction crushed stone pile top reinforcement method and device of the present invention.

[0046] Figure 11This is a schematic diagram of step 6 of the construction method for shallow reinforcement of crushed stone piles using the soft soil vibratory compaction crushed stone pile top reinforcement method and device of the present invention;

[0047] Figure 12 This is a schematic diagram of step 7 of the construction method for shallow reinforcement of crushed stone piles using the soft soil vibratory compaction crushed stone pile top reinforcement method and device of the present invention;

[0048] Figure 13 This is a schematic diagram of step 8 of the construction method for shallow reinforcement of crushed stone piles using the soft soil vibratory compaction crushed stone pile top reinforcement method and device of the present invention.

[0049] The components shown in the figure and their corresponding markings are: ground 1, reinforced area elevation 2, pile bottom elevation 3, crushed stone 4, cement grout 5, crushed stone pores 6, vibratory compactor 7, crane 8, positioning device 9, grouting pipe 10, screw 11, grouting pipe mounting hole 12, rubber ring 13. Detailed Implementation

[0050] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0051] Reference Figure 1 and Figure 5 , Figure 6 In a method and device for reinforcing the top of a vibratory compaction stone pile in soft soil, a shallowly reinforced stone pile is described. The reinforced section is composed of a uniform mixture of crushed stone (4) and cement grout (5), which greatly enhances the overall strength of this section and effectively solves the engineering problems of high upper stress, low soil constraint, and easy bulging deformation of the stone pile under load. Furthermore, the length of the reinforced section can be adjusted according to the actual engineering conditions, offering advantages such as low cost and high flexibility. The unreinforced section consists of crushed stone (4) and pores (6) in the lower part of the pile. The surrounding soil provides sufficient radial constraint to the stone pile, making it less prone to bulging failure and having a relatively small impact on the overall bearing capacity of the pile. Therefore, retaining the original granular material structure of the stone pile is beneficial for accelerating the drainage consolidation process of the soft soil foundation and saving economic costs.

[0052] Reference Figure 2 This invention provides a device and method for reinforcing the top of a vibratory compaction stone pile in soft soil. The device mainly includes a positioning device 9 and a grouting pipe 10. This invention comprises a device for reinforcing the top of a vibratory compaction stone pile in soft soil, which can be installed at the shallow part of the pile hole and used in conjunction with a vibratory compactor. It includes a grouting pipe 10 and a positioning device 9.

[0053] The vibratory compactor 7 is a commonly used construction vibratory compactor with a diameter of 426mm, and the planned crushed stone pile diameter is 1000mm. The grouting pipe 10 is a pre-embedded pile foundation grouting pipe, made of stainless steel, with a diameter of 48mm. It serves as the drop channel for the vibratory compactor 7, and its outer ring diameter is larger than the planned pile diameter, allowing it to be stably positioned around the pile hole on the ground. The positioning device 9 is an overall circular ring structure. The positioning device 9 is configured as two assemblable semi-circular rings, made of metal, connected by screws 11. The outer ring diameter is larger than the pile hole diameter, and four screws 11 are installed around it. The positioning device 9 can be tightly fitted to the ground 1 through the screws 11, serving a fixing and precise positioning function. The inner ring hole diameter of the positioning device 9 is larger than the vibratory compactor 7 diameter but smaller than the pile diameter by 80mm; it serves as the drop channel for the vibratory compactor 7. Eight small round holes are symmetrically arranged around the inner ring as grouting pipe installation holes 12. The installation holes 12 are located between the pile hole wall and the vibratory compactor 7. Rubber rings 13 are installed on the wall of the grouting pipe installation holes 12 to ensure a tight connection between the grouting pipe 10 and the positioning device 9 and facilitate assembly. Four screw holes are arranged around the outer ring, and the positioning device 9 can be fixed to the ground with screws 11. The positioning device is a two-part semi-circular ring that can be assembled for easy placement around the vibratory compactor 7. During normal operation, the two semi-circular rings are assembled with screws.

[0054] Reference Figure 2 During construction, the traditional vibratory compaction method is first used to form holes and fill the filler using a vibratory compactor 7 and a crane 8. Next, when the filler reaches the preset reinforcement zone elevation 2, the two semi-circular rings of the positioning device 9 are assembled around the vibratory compactor 7 and fixed to the ground 1. Eight grouting pipes 10 are then lowered to the predetermined depth, and filling continues. Finally, after filling is completed, the vibratory compactor 7 and crane 8 are removed, grouting begins, and the grouting pipes 10 are slowly and uniformly pulled up until they are pulled out of the ground, completing the grouting reinforcement process. The entire system coordinates effectively, allowing for flexible selection of reinforcement locations and saving economic costs.

[0055] Reference Figures 7 to 13 The present invention discloses a method and device for reinforcing the top of vibratory compaction stone piles in soft soil. The construction method for shallow reinforcement of stone piles is as follows:

[0056] ①For example Figure 7 As shown, the ground of the construction site 1 is cleared and leveled, the pile positions are arranged, and the vibratory compactor 7 and crane 8 are in place.

[0057] ②For example Figure 8 As shown, start the vibratory compactor 7, control the water pressure and volume, and sink it into the soil until it reaches the bottom elevation 3 of the pile.

[0058] ③ As shown in the figure, after drilling, the vibratory compactor 7 is raised to the hole opening while flushing with water, and then lowered to the bottom of the hole. This process is repeated several times to enlarge the hole diameter, clean the soil inside the hole, and prepare for pile making.

[0059] ④ For example Figure 9As shown, fill the hole with crushed stone material 4, and compact it while filling.

[0060] ⑤ For example Figure 10 As shown, when the crushed stone 4 is filled to the elevation 2 of the reinforced area, place the two halves of the positioning device 9 around the vibratory compactor 7, and assemble the two halves into one piece with screws 11 and fix it to the ground 1. Install the grouting pipe 10 and lower it to the elevation 2 of the reinforced area.

[0061] ⑥ For example Figure 11 As shown, continue filling until filling is complete, then remove the vibratory compactor 7 and the crane 8.

[0062] ⑦ For example Figure 12 As shown, grouting begins, and the grouting pipe 10 is slowly and evenly pulled up to ensure that the cement grout 5 and the crushed stone 4 are evenly mixed at each reinforcement depth, resulting in a good reinforcement effect.

[0063] ⑧ For example Figure 13 As shown, continue step ⑦ until grouting reaches the borehole opening, completing the shallow crushed stone material 4 grouting reinforcement. At this point, the grouting reinforcement is complete, and the single pile construction is finished.

[0064] During the grouting reinforcement and pile fabrication process, it is essential to ensure that the positioning device 9 is fully and accurately fixed to the ground 1. The grouting process should be carried out at a uniform and slow pace, with multiple grouting pipes 10 being pulled upwards simultaneously to ensure thorough mixing of the grout and aggregate, effectively improving the quality of the pile. After grouting is completed and the reinforcement grout has solidified, the quality of the pile can be inspected to ensure it meets the requirements.

[0065] Studies show that traditional crushed stone piles are prone to bulging failure within a depth range of 1 to 3 times the pile diameter at the pile top. To address this, a conservative reinforcement zone depth of 5 times the pile diameter can be considered. For example, if the crushed stone pile diameter is 1000mm, the reinforcement zone depth should be 5000mm, or 5m underground.

[0066] Using the methods described above, devices of different sizes can be prepared according to different pile-making requirements to reinforce the shallow part of the crushed stone pile composite foundation.

[0067] The above embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for reinforcing the top of vibratory compaction stone piles in soft soil, characterized in that, The apparatus used in the method includes: a positioning device and a grouting pipe; The positioning device consists of two assemblable semicircular rings, with mounting holes for the positioning device and grouting pipe on the rings. The mounting holes for the positioning device are used to install the positioning device on the ground, serving to fix and accurately position it. The outer ring diameter of the positioning device is larger than the pile hole diameter, and the distance from the mounting hole of the positioning device to the center of the ring is larger than the pile hole radius. The inner ring diameter of the positioning device is larger than the vibratory compactor diameter but smaller than the pile hole diameter, serving as a channel for the vibratory compactor to fall. The grouting pipe passes through the grouting pipe installation hole to reinforce the top of the pile with grout. In the positioning device, the two semi-circular rings are connected by screws; The positioning device is tightly attached to the ground at the mounting hole of the positioning device by screws, which serves to fix and accurately position the device. A rubber ring is attached to the inner side of the grouting pipe mounting hole for a tight connection between the grouting pipe and the positioning device. Specifically, the steps include the following: Step 1: Clear and level the construction site, arrange the pile positions, and position the vibratory compactor and crane; Step 2: Start the vibratory compactor, determine the water pressure and volume, and sink it into the soil until the bottom elevation of the pile is reached; Step 3: After drilling, lift the vibratory compactor to the hole opening and flush it with water, then lower it to the bottom of the hole. Repeat this step to enlarge the hole diameter, clean the soil inside the hole, and prepare for pile making. Step 4: Fill the hole with crushed stone and compact it by vibration during filling; Step 5: When the crushed stone is filled to the elevation of the reinforced area, place the two semi-circular rings of the positioning device around the vibratory compactor, assemble the two semi-circular rings into one piece, and fix it on the ground; install the grouting pipe on the positioning device and lower it to the elevation of the reinforced area. Step 6: Continue filling until filling is complete, then remove the vibratory compactor and crane; Step 7: Start grouting, slowly and evenly pull up the grouting pipe to ensure that the cement grout and crushed stone are mixed evenly in the reinforced area; traditional crushed stone piles are prone to bulging failure within a depth range of 1 to 3 times the pile diameter at the top of the pile. In view of this situation, the depth of the reinforced area is conservatively taken as 5 times the pile diameter. Step 8: Continue grouting to the borehole opening to complete the shallow crushed stone grouting reinforcement; at this point, the grouting reinforcement is complete and the single pile construction is finished.

2. The method for reinforcing the top of vibratory compaction stone piles in soft soil according to claim 1, characterized in that, During the grouting reinforcement and filling pile fabrication process, it is necessary to ensure that the positioning device is fully fixed to the ground and that the positioning is accurate.

3. The method for reinforcing the top of vibratory compaction stone piles in soft soil according to claim 1, characterized in that, The grouting process should be carried out at a uniform and slow speed, with multiple grouting pipes being pulled up simultaneously to ensure thorough mixing of the grout and aggregate.

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