A mechanical compaction and grouting construction method for treating sediment at the bottom of a cast-in-place pile

Abstract

The invention relates to a mechanical compaction and grouting construction method for treating sediment at the bottom of a bored pile, comprising the following construction steps: S1, fixing a hydraulic jacking grouting device and a high-pressure grouting device at the bottom end of a steel cage, and hoisting the steel cage into a designed depth position in a pile hole; S2, grouting the pile hole through a concrete guide pipe to form a reinforced concrete bored pile; S3, after the bored pile is cured for 1 to 3 days, starting a hydraulic station to push a pressing plate in a hydraulic extrusion device downward along the axial direction of the bored pile, and strongly compacting and compacting a mixture of concrete and sediment at the bottom of the bored pile; S4, a transverse crack space is generated in a concrete pile section at the bottom of the bored pile, and cement slurry is subjected to high-pressure grouting to the crack space and the pile side through a grouting pipeline under high pressure until the standard is met; S5, after several days of high-pressure grouting, the concrete and sediment mixture at the bottom of the bored pile can be compacted and solidified; the invention can improve the strength of the concrete and sediment mixture at the pile end and the bearing capacity of the foundation pile.

Description

Technical Field

[0001] The invention belongs to the technical field of pile foundation engineering, and in particular relates to a mechanical compaction and grouting construction method for treating sediment at the bottom of a cast-in-place pile. Background Art

[0002] Reinforced concrete bored piles have been widely used in infrastructure construction such as high-rise buildings, transportation projects, and municipal projects. They have the advantages of low cost, high bearing capacity, and efficient construction. However, there is a major defect in bored pile construction, that is, a certain thickness of sediment will be formed at the bottom of the pile during the hole construction and cage construction process. The sediment at the bottom of the pile will cause technical problems such as reduced bearing capacity of the foundation pile and excessive settlement, and will cause many engineering quality problems of bored piles. In order to reduce the thickness of sediment at the bottom of the pile, hole cleaning measures are generally used in bored pile construction to reduce the thickness of sediment at the bottom of the pile. However, in actual projects, hole cleaning construction often fails to meet the technical requirements of pile foundation specifications for the thickness of sediment at the bottom of the pile.

[0003] In the prior art, in order to solve the above-mentioned construction technology difficulties, the pile end post-grouting technology is usually used in the construction of bored piles, and the pile bottom sediment is compacted by means of the post-grouting technology to improve the single pile bearing capacity of the bored pile. However, since the effect of pile end post-grouting is often affected by the rock and soil type of the pile end, the grouting equipment and the grouting process, especially in clay and soft clay layers, the quality of post-grouting is difficult to control and the effect is poor, the reliability of post-grouting construction is low. In addition, traditional post-grouting construction cannot effectively control the grouting pressure, slurry flow direction and diffusion and compaction range, and it is difficult to solve the problem of uncertainty in the effect of post-grouting construction. Therefore, in order to ensure that the bored pile meets the design requirements of bearing capacity and settlement, the traditional pile end post-grouting technology needs to be innovatively developed. Summary of the invention

[0004] The purpose of the present invention is to provide a mechanical compaction and grouting construction method for treating sediment at the bottom of a bored pile, so that the sediment at the bottom of the bored pile can be effectively compacted and compacted through a controllable quantitative technology, so as to improve the strength of the mixture of pile end concrete and sediment and the bearing capacity of the foundation pile, reduce the settlement of the foundation pile, and significantly reduce the cost of the bored pile.

[0005] The object of the present invention is achieved through the following technical scheme. The mechanical compaction and grouting construction method for treating sediment at the bottom of cast-in-place piles comprises the following construction steps:

[0006] S1. Install and fix the hydraulic extrusion device on the bottom end of the steel cage, and connect the high-pressure grouting device to the hydraulic extrusion device. Stably lift the steel cage with the hydraulic extrusion device and the high-pressure grouting device into the pile hole to the designed depth position, and the distance between the bottom end of the steel cage and the pile bottom is greater than 10 cm;

[0007] S2, pouring concrete into the pile hole from bottom to top through a concrete conduit to form a reinforced concrete cast-in-place pile;

[0008] S3, after the bored pile has been cured for 1 to 3 days, the hydraulic station is started, and each hydraulic extrusion unit in the hydraulic extrusion device 1 is controlled by the hydraulic drive of the hydraulic station to slowly push, thereby pushing the pressing plate in the hydraulic extrusion device vertically downward along the bored pile, and strongly compacting the mixture of concrete and sediment at the bottom of the bored pile;

[0009] S4. After the pressing plate is pushed vertically downward, a transverse crack space is generated in the bottom concrete pile section of the bored pile, and then the high-pressure grouting pump in the high-pressure grouting device is started, and cement slurry is injected into the annular transverse grouting pipeline through the grouting pipeline under high pressure, and each grouting hole in the annular transverse grouting pipeline is unplugged, and then high-pressure grouting is performed through the grouting holes to the crack space of the bottom pile section of the bored pile and the pile side, and the high-pressure grouting is terminated after the standard is met;

[0010] S5. After 15 days of high-pressure grouting, the mixture of concrete and sediment at the bottom of the bored pile is compacted and solidified to form a complete bored pile, achieving the purpose of increasing the bearing capacity of the foundation pile and reducing the settlement.

[0011] Preferably, the distance between the bottom end of the steel cage and the bottom of the pile in step S1 is 10 cm to 50 cm.

[0012] Preferably, the height of the crack space in step S4 is 2 cm to 30 cm; the grouting pressure value of the high-pressure grouting pump is 1 to 10 MPa, and the grouting flow value is 50 to 80 L / min.

[0013] Preferably, the hydraulic extrusion device is arranged at the bottom end of the steel cage of the bored pile and is fixedly connected to the steel cage, the high-pressure grouting device is connected to the hydraulic extrusion device, and the high-pressure grouting device moves downward along the axial direction of the bored pile as the driving end of the hydraulic extrusion device pushes; the driving end of the hydraulic extrusion device pushes downward along the axial direction of the bored pile to compact the mixture of concrete and sediment at the bottom of the pile, and creates a transverse crack space in the bottom concrete pile section of the bored pile, and high-pressure grouting is performed on the crack space and the pile side through the grouting end of the high-pressure grouting device.

[0014] Preferably, the hydraulic extrusion device includes a pressure plate, a steel hoop and a driving mechanism for driving the pressure plate to move vertically, the steel hoop is connected to the bottom end of the steel cage, the driving mechanism is installed on the steel hoop, the upper end surface of the pressure plate is connected to the driving end of the driving mechanism, and the lower end surface of the pressure plate faces the sediment at the bottom of the pile.

[0015] Preferably, the driving mechanism includes a hydraulic extrusion unit and a hydraulic station arranged on the ground, the hydraulic extrusion unit is tightly attached to the inner side of the steel hoop and fixed, the hydraulic station is used to provide a power source for the hydraulic extrusion unit, and the pressure plate is connected to the driving end of the hydraulic extrusion unit; a through hole is provided in the center of the pressure plate and the cross-section of the pressure plate is a ring shape.

[0016] Preferably, the hydraulic extrusion device also includes a transverse hydraulic pipeline and a vertical hydraulic pipeline, the vertical hydraulic pipeline is connected to the transverse hydraulic pipeline, and the vertical hydraulic pipeline is located on the inner side of the steel hoop and passes through the cast-in-place pile and is sealed and connected to the oil outlet provided in the hydraulic station.

[0017] Preferably, the steel cage comprises a plurality of vertical main bars, spiral stirrups and a plurality of connecting bars, the plurality of vertical main bars are arranged in a circumferential direction, and the spiral stirrups are tied and fixed on the outer circumference of the plurality of vertical main bars, the upper ends of the plurality of connecting bars are respectively connected to the lower end sections of the plurality of vertical main bars, and the lower ends of the plurality of connecting bars are respectively connected to the steel hoop.

[0018] Preferably, the high-pressure grouting device comprises a vertical grouting pipe, a vertical grouting telescopic pipe, an annular grouting groove fixed on the upper end surface of the pressure plate and a high-pressure grouting pump arranged on the ground surface, the lower end of the vertical grouting pipe is connected to the upper end of the vertical grouting telescopic pipe, the vertical grouting pipe passes through the cast-in-place pile and is connected to the outlet end of the high-pressure grouting pump, the lower end of the vertical grouting telescopic pipe passes through the through hole provided on the upper end surface of the annular grouting groove and is connected to the annular transverse grouting pipeline installed in the annular grouting groove, and the side wall of the annular transverse grouting pipeline is provided with a plurality of grouting holes distributed in the circumferential direction; the plurality of grouting holes are closed with rubber sleeves to form a plurality of one-way grouting valves, and under the pressure injection of high-pressure cement slurry, the plurality of grouting holes can realize one-way grouting from the grouting holes to the outside thereof.

[0019] Preferably, a flexible sealing sleeve is provided at one end of the vertical grouting telescopic pipe close to the vertical grouting pipe, the lower end of the vertical grouting pipe is slidably inserted in the upper end of the vertical grouting telescopic pipe, the inner side wall of the upper end of the flexible sealing sleeve is sealed on the outer side wall of the vertical grouting pipe, and the flexible sealing sleeve and the vertical grouting pipe are slidable along the axial direction.

[0020] The beneficial effects of the present invention are as follows: by adopting the mechanical compaction and grouting construction method and based on a reliable and controllable hydraulic extrusion device and a high-pressure grouting device, the bearing capacity of the bored piles can be greatly improved through the combined application and effective implementation of the hydraulic extrusion device and the high-pressure grouting device, and the pile foundation design can be changed with certainty, that is, the design length of the foundation piles can be shortened or the total number of foundation piles can be reduced, thereby achieving the purpose of shortening the construction period and greatly reducing the project cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the overall structure of the cast-in-place pile according to Embodiment 1 of the present invention;

[0022] Figure 2 is a schematic structural diagram of a hydraulic extrusion device according to Embodiment 1 of the present invention;

[0023] Figure 3 1 is a schematic structural diagram of a high-pressure grouting device according to Embodiment 1 of the present invention;

[0024] Figure 4 is a schematic diagram of the connection structure between the steel cage and the steel hoop according to Example 1 of the present invention;

[0025] Figure 5 1 is a schematic top view of the structure of the mechanical compaction and grouting system of Example 1 of the present invention;

[0026] Figure 6 is a schematic cross-sectional view of the structure of the mechanical compaction and grouting system of Example 1 of the present invention;

[0027] Figure 7 1 is a schematic top view of the structure of the mechanical compaction and grouting system of Example 2 of the present invention;

[0028] Figure 8 It is a schematic cross-sectional view of the structure of the mechanical compaction and grouting system of Example 2 of the present invention.

[0029] The numbers in the accompanying drawings are respectively: 1. hydraulic extrusion device; 2. high-pressure grouting device; 3. driving mechanism; 4. hydraulic extrusion unit; 5. vertical hydraulic pipeline; 6. hydraulic station; 7. vertical grouting pipe; 8. vertical grouting telescopic pipe; 9. annular horizontal grouting pipeline; 10. annular grouting channel; 11. flexible sealing sleeve; 12. steel cage; 13. vertical main reinforcement; 14. spiral stirrups; 15. connecting reinforcement; 16. steel hoop; 17. pressure plate; 18. horizontal hydraulic pipeline; 20. cast-in-place pile; 24. high-pressure grouting pump; 25. oil inlet valve; 26. grouting hole; 27. rubber sleeve; 28. one-way grouting valve. DETAILED DESCRIPTION

[0030] The present invention will be described in detail below in conjunction with the accompanying drawings: The mechanical compaction and grouting construction method of the present invention comprises the following construction steps:

[0031] S1, the hydraulic extrusion device 1 is fixed on the bottom end of the steel cage 12, and the high-pressure grouting device 2 is connected to the hydraulic extrusion device 1, and the steel cage 12 with the hydraulic extrusion device 1 and the high-pressure grouting device 2 is stably hoisted into the designed depth position in the pile hole, and the distance between the bottom end of the steel cage 12 and the pile bottom is greater than 10cm;

[0032] S2, pouring concrete into the pile hole from bottom to top through a concrete conduit to form a reinforced concrete cast-in-place pile 20;

[0033] S3, after the bored pile 20 has been cured for 1 to 3 days, the hydraulic station 6 is started, and the hydraulic extrusion units 4 in the hydraulic extrusion device 1 are controlled by the hydraulic drive of the hydraulic station 6 to slowly push, thereby pushing the pressing plate 17 in the hydraulic extrusion device 1 vertically downward along the axial direction of the bored pile 20, and strongly compacting the mixture of concrete and sediment at the bottom of the bored pile 20;

[0034] S4, after the pressing plate 17 is pushed vertically downward, a transverse crack space is generated in the bottom concrete pile section of the bored pile 20, and then the high-pressure grouting pump 24 in the high-pressure grouting device 2 is started, and cement slurry is injected into the annular transverse grouting pipeline 9 through the grouting pipeline under high pressure, and each grouting hole 26 in the annular transverse grouting pipeline 9 is unplugged, and then continuous high-pressure grouting is performed through the grouting holes 26 to the crack space and pile side of the bottom pile section of the bored pile 20, and the termination condition of the high-pressure grouting requires that the designed maximum grouting pressure and / or the designed total grouting amount are met;

[0035] S5. 15 days after the high-pressure grouting is completed, the mixture of the concrete and the sediment at the bottom of the bored pile 20 is compacted and solidified to form a complete bored pile 20, thereby achieving the purpose of improving the bearing capacity of the foundation pile and reducing the settlement.

[0036] The preferred distance between the bottom end of the steel cage 12 and the bottom end of the pile hole in step S1 is 10 cm to 50 cm; this facilitates the smooth return of the bottom sediment of the bored pile 20 during the concrete pouring process, and can further enable the mixture of the bottom concrete and sediment of the bored pile 20 to fully contact and mix, thereby enabling the above-mentioned mechanical jacking grouting construction method to obtain better construction results.

[0037] The preferred height of the crack space in step S4 is 2 cm to 30 cm; the diameter of the crack space is close to the pile diameter of the cast-in-place pile 20, and the height of the crack space can be determined according to the rock and soil properties of the stratum, the pile forming process and the jacking stroke, and can be achieved by accurately controlling the stroke size of the hydraulic extrusion device 1 through the hydraulic oil flow of the hydraulic station 6 during construction. The grouting pressure value is related to the rock and soil properties, and the design length of the pile should also be considered. The grouting pressure value of the high-pressure grouting pump 24 is in the range of 1 to 10 MPa, and the grouting flow value is 50 to 80 L / min. The total amount of grouting for a single pile should be determined according to the geometric size of the pile, the size of the crack space, and the rock and soil properties.

[0038] As attached Figures 1 to 8As shown, the hydraulic extrusion device 1 is arranged at the bottom end of the steel cage 12 of the bored pile 20 and is fixedly connected to the steel cage 12. The high-pressure grouting device 2 is connected to the hydraulic extrusion device 1, and the high-pressure grouting device 2 moves downward along the axial direction of the bored pile 20 as the driving end of the hydraulic extrusion device 1 pushes. The driving end of the hydraulic extrusion device 1 pushes downward along the axial direction of the bored pile 20 to compact the mixture of concrete and sediment at the bottom of the pile, and a transverse crack space is generated in the bottom concrete pile section of the bored pile 20. Thereafter, the high-pressure grouting device is used to perform quantitative pressure grouting to achieve effective compaction and compaction of the sediment at the bottom of the pile, thereby ultimately achieving the purpose of improving the bearing capacity of the foundation pile and reducing the engineering cost.

[0039] The hydraulic extrusion device 1 includes a pressing plate 17, a steel hoop 16 and a driving mechanism 3 for driving the pressing plate 17 to move vertically. The steel hoop 16 is connected to the bottom end of the steel cage 12, and the driving mechanism 3 is installed on the steel hoop 16. The upper end surface of the pressing plate 17 is connected to the driving end of the driving mechanism 3, and the lower end surface of the pressing plate 17 faces the sediment at the bottom of the pile. In this way, when the pressing plate 17 is pushed by the driving mechanism 3, the pressing plate 17 can directly and effectively squeeze and compact the sediment at the bottom of the pile.

[0040] The driving mechanism 3 includes a hydraulic extrusion unit 4 and a hydraulic station 6 arranged on the surface. The hydraulic extrusion unit 4 is tightly attached to the inner side of the steel hoop 16 and fixed, so that the structure of the entire driving mechanism in the bored pile 20 is more compact and the space is effectively utilized; the hydraulic station 6 is used to provide a power source for the hydraulic extrusion unit 4, and the pressure plate 17 is connected to the driving end of the hydraulic extrusion unit 4, and the hydraulic extrusion unit 4 is a jack; in this way, the jacking pressure and the jacking stroke can be accurately controlled by the hydraulic station located on the surface, thereby ensuring the realization of the designed cracking space size of the concrete pile section at the bottom of the bored pile, and using the high-pressure grouting device 2 to effectively control the pressure grouting diffusion path, distribution space and total grouting amount.

[0041] The hydraulic extrusion device 1 also includes a transverse hydraulic pipeline 18 and a vertical hydraulic pipeline 5. The vertical hydraulic pipeline 5 is connected to the transverse hydraulic pipeline 18, and the vertical hydraulic pipeline 5 is located on the inner side of the steel hoop 16, and passes through the cast-in-place pile 20 and is sealed and connected to the oil outlet provided in the hydraulic station 6; in this way, the hydraulic extrusion unit 4 can be connected in series and controlled simultaneously through the transverse hydraulic pipeline 18, and can be directly controlled by the hydraulic station 6 through the vertical hydraulic pipeline 5; the transverse hydraulic pipeline 18 is located in the annular grouting channel 10 or on the upper end surface of the outer wall of the annular grouting channel 10.

[0042] There are three hydraulic extrusion units 4, and the hydraulic extrusion units 4 are evenly distributed along the circumference of the steel hoop 16 and fixed on the upper end surface of the pressure plate 17. The oil inlet of each hydraulic extrusion unit 4 is connected in series through a transverse hydraulic pipeline 18; this makes the hydraulic extrusion unit 4 more stable during the process of pushing the pressure plate 17.

[0043] The steel cage 12 includes a plurality of vertical main bars 13, spiral stirrups 14 and a plurality of connecting bars 15. The plurality of vertical main bars 13 are arranged in a circumferential direction, and the spiral stirrups 14 are bundled and fixed on the outer peripheral side of the plurality of vertical main bars 13. The upper ends of the plurality of connecting bars 15 are respectively connected to the lower end sections of the plurality of vertical main bars 13, and the lower ends of the plurality of connecting bars 15 are respectively connected to the steel hoop 16; this makes the steel hoop 16 more stable after being fixed.

[0044] A through hole is provided at the center of the pressing plate 17 and the cross section of the pressing plate 17 is in a ring shape, so that when the cast-in-place pile 20 is poured, it is convenient for the sediment to return from the central through hole of the pressing plate 17 .

[0045] The high-pressure grouting device 2 includes a vertical grouting pipe 7, a vertical grouting telescopic pipe 8, an annular grouting groove 10 fixed on the upper end surface of the pressure plate 17, and a high-pressure grouting pump 24 arranged on the ground surface. The lower end of the vertical grouting pipe 7 is connected to the upper end of the vertical grouting telescopic pipe 8. The vertical grouting pipe 7 passes through the bored pile 20 and is connected to the outlet end of the high-pressure grouting pump 24. The lower end of the vertical grouting telescopic pipe 8 passes through the through hole provided on the upper end surface of the annular grouting groove 10 and is connected to the annular transverse grouting pipeline 9 installed in the annular grouting groove 10, and the side wall of the annular transverse grouting pipeline 9 is provided with a plurality of grouting holes 26 distributed along the circumferential direction. Through the arrangement of the high-pressure grouting device 2, quantitative pressure grouting can be performed by using the high-pressure grouting device for the crack space of the pile section at the bottom of the bored pile, so as to achieve effective compaction and compaction of the sediment at the bottom of the pile, and finally achieve the purpose of improving the bearing capacity of the foundation pile and reducing the engineering cost.

[0046] A flexible sealing sleeve 11 is provided at one end of the vertical grouting telescopic pipe 8 close to the vertical grouting pipe 7, and the lower end of the vertical grouting pipe 7 is slidably inserted in the upper end of the vertical grouting telescopic pipe 8. The inner wall of the upper end of the flexible sealing sleeve 11 is sealed on the outer wall of the vertical grouting pipe 7, and the flexible sealing sleeve 11 and the vertical grouting pipe 7 are axially slidable; when the pressure plate 17 moves vertically downward along the axial direction of the bored pile 20 under the pushing action of the hydraulic extrusion unit 4, the vertical grouting telescopic pipe 8 will produce vertical displacement accordingly to ensure the smooth flow of the cement slurry high-pressure grouting pipeline and maintain the smooth flow of all cement slurry grouting pipelines.

[0047] The outside of the multiple grouting holes 26 are all closed with rubber sleeves 27 to form multiple one-way grouting valves 28. Under high-pressure cement slurry pressure injection, the multiple grouting holes 26 can realize one-way grouting from the grouting holes 26 to the outside; this not only prevents concrete slurry from entering the grouting holes 26 when pouring the bored piles 20, but also facilitates high-pressure grouting into the crack space through the grouting holes 26, and can timely open the rubber sleeves 27 to realize one-way grouting; when cement slurry injection is not used, the rubber sleeves 27 shrink and seal the grouting holes 26.

[0048] Example 1

[0049] Below is a combination of the embodiments and the attached Figures 1 to 6 The mechanical compaction and grouting system of the present invention is further described. The embodiment is a bored pile with a pile length of 30m and a pile diameter of 800mm. The outer diameter of the steel cage 12 is 700mm and the inner diameter is 660mm. The steel cage 12 is provided with 8 vertical main bars 13 with a diameter of 20mm and 2 vertical grouting pipes 7. The bearing layer at the pile end is dense silt, and the standard value of the ultimate end resistance is 1000kPa.

[0050] By using the mechanical compaction and grouting system of the pile end of the present invention, three hydraulic squeezing units 4 are evenly distributed and fixed on the pressure plate 17 with a center hole, and are fixedly connected to the inner side of the steel hoop 16 by welding. The hydraulic squeezing units 4 are connected in series by a transverse hydraulic pipeline 18, and are connected by a retractable vertical hydraulic pipeline 5 and an oil inlet valve 25 provided in a hydraulic station 6. The retractable vertical hydraulic pipeline 5 can refer to the connection relationship between the vertical grouting pipe 7 and the vertical grouting telescopic pipe 8 in the high-pressure grouting device 2. The retractable vertical hydraulic pipeline 5 will not be moved with the liquid. The pressure extrusion unit 4 is broken during the movement; the vertical grouting pipe 7 is connected to the high-pressure grouting pump 24, the lower end of the vertical grouting pipe 7 is connected to the upper end of the vertical grouting telescopic pipe 8, the bottom end of the vertical grouting telescopic pipe 8 passes through the through hole on the upper end surface of the annular grouting groove 10, and is fixedly connected to the annular transverse grouting pipeline 9 in the annular grouting groove 10, the bottom of the annular grouting groove 10 and the top surface of the pressure plate 17 are welded and fixed, the vertical main reinforcement 13 and the steel hoop 16 are welded and fixed, and the lower end of the connecting reinforcement 15 fixes the vertical main reinforcement 13 and the steel hoop 16 together by welding.

[0051] In this embodiment, the number of hydraulic extrusion units 4 is 3, and the diameter of each hydraulic extrusion unit 4 is 140 mm. The three hydraulic extrusion units 4 are connected in series through a transverse hydraulic pipeline 18 to form an annular hydraulic passage. The transverse hydraulic pipeline 18 and the oil inlet of the hydraulic extrusion unit 4 are connected to the oil valve. The vertical hydraulic pipeline 5 passes vertically downward through the through hole on the upper end surface of the annular grouting channel 10 along the side wall of the vertical hydraulic extrusion unit assembly 4. The transverse hydraulic pipeline 18 is laid in an annular manner inside the annular grouting channel 10. A transverse hydraulic pipeline 18 near the oil inlet of the hydraulic extrusion unit 4 is reserved. A distance is reserved near the annular grouting channel 10 for the telescopic vertical hydraulic pipeline 5 to ensure that the transverse hydraulic pipeline 18 is not broken when the pressure plate 17 moves downward; an oil valve is used to connect the retractable vertical hydraulic pipeline 5 and the transverse hydraulic pipeline 18 to form a hydraulic passage; the retractable vertical hydraulic pipeline 5 extends upward along the vertical grouting pipe 7 to the ground and is sealedly connected to the hydraulic station 6; the retractable vertical hydraulic pipeline 5 and the vertical grouting pipe 7 are tied together with the vertical main reinforcement 13 by steel wire; a distance is reserved near the annular grouting channel 10 for the telescopic vertical hydraulic pipeline 5 to ensure that the retractable vertical hydraulic pipeline 5 is not broken when the pressure plate 17 moves downward.

[0052] The loading capacity of the hydraulic extrusion unit 4 in this embodiment depends on the standard value of the ultimate end resistance of the rock and soil at the pile end and the number of hydraulic extrusion units 4. According to the pile foundation design, the ultimate end bearing capacity of the cast-in-place pile 20 in this embodiment is 44 tons, and the loading capacity of a single hydraulic extrusion unit 4 in this embodiment is selected to be 15 tons to meet the requirements.

[0053] In this embodiment, the pressing plate 17 is an annular steel plate, the outer diameter of the pressing plate 17 is slightly smaller than the inner diameter of the steel cage 12, and the return grout hole in the center of the pressing plate 17 is circular with a diameter of 350 mm, which can meet the technical requirements of normal return of pile bottom sediment upward during the pouring of pile body concrete.

[0054] In this embodiment, the vertical grouting pipe 7 is selected to be two steel pipes, which are symmetrically distributed along the steel cage. The lower part of the vertical grouting pipe 7 and the upper part of the vertical grouting telescopic pipe 8 are connected by a sleeve, and the vertical grouting pipe 7 and the vertical main reinforcement 13 of the steel cage 12 are fixedly connected.

[0055] The annular transverse grouting pipeline 9 is placed in a ring shape inside the annular grouting channel 10. The annular transverse grouting pipeline 9 and the bottom end of the vertical grouting telescopic pipe 8 are fixedly connected to form a grouting passage. Eight grouting holes 26 are evenly and symmetrically arranged on the annular transverse grouting pipeline 9, and the outside of the eight grouting holes 26 are closed with rubber sleeves 27 to form eight one-way grouting valves 28. The grouting holes of the one-way grouting valves 28 are arranged to face the center direction of the pressure plate 17 to ensure that the one-way grouting valves 28 can achieve one-way grouting from the annular transverse grouting pipeline 9 to the outside under the impact of high-pressure cement slurry.

[0056] In this embodiment, the inner diameter of the two vertical grouting telescopic pipes 8 is slightly larger than the outer diameter of the two vertical grouting pipes 7. The upper part of the vertical grouting telescopic pipe 8 is connected to the lower part of the vertical grouting pipe 7, and the flexible sealing sleeve 11 is used to flexibly close the connecting port. The bottom end of the vertical grouting telescopic pipe 8 passes through the through hole on the upper end surface of the annular grouting groove 10 and is fixedly connected to the annular horizontal grouting pipeline 9 to form a grouting passage.

[0057] Example 2

[0058] Embodiment 2 is another implementation of the mechanical compaction and grouting system of the present invention, such as Figure 7 and Figure 8 As shown, this embodiment adopts the same pile design parameters as in Embodiment 1, and this embodiment will not repeat the description of the components similar to those in Embodiment 1. The difference between this embodiment and Embodiment 1 is that Figure 7As shown, the hollow in the center of the pressing plate 17 is of a special shape, and the number of the hydraulic squeezing units 4 is 4, which are evenly and symmetrically distributed around the pressing plate 17. Compared with the circular pressing plate 17 in Example 1, the special-shaped central hole pressing plate 17 used in this embodiment can save the material of the pressing plate 17, reduce the overall weight of the pile end mechanical jacking grouting system, and provide a larger middle hole to ensure that the pile bottom sediment can be better returned upward when the pile body concrete is poured, thereby reducing the thickness of the pile end sediment. In this embodiment, the annular grouting channel 10 is arranged in a transversely concave manner, which is conducive to improving the success rate of grouting and plugging of the rubber sleeve 27 on the grouting hole 26.

[0059] It is understandable that, for those skilled in the art, any equivalent replacement or change to the technical solution and inventive concept of the present invention should fall within the protection scope of the claims attached to the present invention.

Claims

1. A mechanical compaction and grouting construction method for treating sediment at the bottom of a cast-in-place pile, characterized in that: The construction steps include: S1. Install and fix the hydraulic extrusion device (1) on the bottom end of the steel cage (12), connect the high-pressure grouting device (2) to the hydraulic extrusion device (1), and stably lift the steel cage (12) with the hydraulic extrusion device (1) and the high-pressure grouting device (2) into the pile hole to the designed depth position, and the distance between the bottom end of the steel cage (12) and the bottom of the pile is not less than 10 cm; S2, pouring concrete into the pile hole from bottom to top through a concrete conduit to form a reinforced concrete cast-in-place pile (20); S3, after the bored pile (20) has been cured for 1 to 3 days, the hydraulic station (6) is started, and each hydraulic squeezing unit (4) in the hydraulic squeezing device (1) is controlled by the hydraulic drive of the hydraulic station (6) to push, thereby pushing the pressing plate (17) in the hydraulic squeezing device (1) vertically downward along the axial direction of the bored pile (20), and strongly compacting the mixture of concrete and sediment at the bottom of the bored pile (20); S4, after the pressure plate (17) is pushed vertically downward, a transverse crack space is generated in the bottom concrete pile section of the bored pile (20), and then the high-pressure grouting pump (24) in the high-pressure grouting device (2) is started, and cement slurry is injected into the annular transverse grouting pipeline (9) through the grouting pipeline under high pressure, and each grouting hole (26) in the annular transverse grouting pipeline (9) is unplugged, and then high-pressure grouting is performed through the grouting holes (26) into the crack space of the bottom pile section of the bored pile (20) and the pile side, and the high-pressure grouting is terminated after the standard is met; S5, after several days of high-pressure grouting, the mixture of the concrete and the sediment at the bottom of the bored pile (20) is compacted and solidified to form a complete bored pile (20), thereby achieving the purpose of improving the bearing capacity of the foundation pile and reducing the settlement; The hydraulic extrusion device (1) comprises a pressing plate (17), a steel hoop (16) and a driving mechanism (3) for driving the pressing plate (17) to move vertically, the steel hoop (16) being connected to the bottom end of the steel cage (12), the driving mechanism (3) being mounted on the steel hoop (16), the upper end surface of the pressing plate (17) being connected to the driving end of the driving mechanism (3), and the lower end surface of the pressing plate (17) facing the pile bottom sediment; The driving mechanism (3) comprises a hydraulic squeezing unit (4) and a hydraulic station (6) arranged on the ground surface, wherein the hydraulic squeezing unit (4) is closely attached to the inner side of the steel hoop (16) and fixed, and the hydraulic station (6) is used to provide a power source for the hydraulic squeezing unit (4). The pressing plate (17) is connected to the driving end of the hydraulic squeezing unit (4); and a through hole is provided at the center of the pressing plate (17) and the cross section of the pressing plate (17) is in a ring shape, so that when the cast-in-place pile (20) is cast, it is convenient for the sediment to return from the central through hole of the pressing plate (17).

2. The mechanical compaction and grouting construction method for treating sediment at the bottom of a cast-in-place pile according to claim 1, characterized in that: The distance between the bottom end of the steel cage (12) and the bottom of the pile in step S1 is 10 cm to 50 cm.

3. The mechanical compaction and grouting construction method for treating sediment at the bottom of a cast-in-place pile according to claim 1, characterized in that: The height of the crack space in step S4 is 2 cm to 30 cm; the grouting pressure value of the high-pressure grouting pump (24) is in the range of 1 to 10 MPa, and the grouting flow rate value is 50 to 80 L / min.

4. The mechanical compaction and grouting construction method for treating sediment at the bottom of a cast-in-place pile according to claim 1, characterized in that: The hydraulic squeezing device (1) is arranged at the bottom end of the steel cage (12) of the bored pile (20) and is fixedly connected to the steel cage (12); the high-pressure grouting device (2) is connected to the hydraulic squeezing device (1), and the high-pressure grouting device (2) moves downward along the axial direction of the bored pile (20) as the driving end of the hydraulic squeezing device (1) pushes; the driving end of the hydraulic squeezing device (1) pushes downward along the axial direction of the bored pile (20) to compact the mixture of concrete and sediment at the bottom of the pile, and to generate a transverse crack space in the bottom concrete pile section of the bored pile (20), and high-pressure grouting is performed on the crack space and the pile side through the grouting end of the high-pressure grouting device (2).

5. The mechanical compaction and grouting construction method for treating sediment at the bottom of a cast-in-place pile according to claim 1, characterized in that: The hydraulic extrusion device (1) further comprises a transverse hydraulic pipeline (18) and a vertical hydraulic pipeline (5), wherein the vertical hydraulic pipeline (5) is connected to the transverse hydraulic pipeline (18), and the vertical hydraulic pipeline (5) is located on the inner side of the steel hoop (16), passes through the cast-in-place pile (20), and is sealed and connected to an oil outlet provided in the hydraulic station (6).

6. The mechanical compaction and grouting construction method for treating sediment at the bottom of a bored pile according to claim 1, characterized in that: The steel cage (12) comprises a plurality of vertical main bars (13), spiral stirrups (14) and a plurality of connecting bars (15); the plurality of vertical main bars (13) are arranged in a circumferential direction, and the spiral stirrups (14) are tied and fixed to the outer circumference of the plurality of vertical main bars (13); the upper ends of the plurality of connecting bars (15) are respectively connected to the lower end sections of the plurality of vertical main bars (13); and the lower ends of the plurality of connecting bars (15) are respectively connected to the steel hoop (16).

7. The mechanical compaction and grouting construction method for treating sediment at the bottom of a bored pile according to claim 1, characterized in that: The high-pressure grouting device (2) comprises a vertical grouting pipe (7), a vertical grouting telescopic pipe (8), an annular grouting channel (10) fixed on the upper end surface of a pressure plate (17), and a high-pressure grouting pump (24) arranged on the ground surface. The lower end of the vertical grouting pipe (7) is connected to the upper end of the vertical grouting telescopic pipe (8). The vertical grouting pipe (7) passes through the cast-in-place pile (20) and is connected to the outlet end of the high-pressure grouting pump (24). The lower end of the vertical grouting telescopic pipe (8) passes through the annular The through hole provided on the upper end surface of the grouting channel (10) is connected to an annular transverse grouting pipeline (9) installed in the annular grouting channel (10), and a plurality of grouting holes (26) distributed along the circumferential direction are provided on the side wall of the annular transverse grouting pipeline (9); the plurality of grouting holes (26) are sealed with rubber sleeves (27) to form a plurality of one-way grouting valves (28); under high-pressure cement slurry injection, the plurality of grouting holes (26) can realize one-way grouting from the grouting holes (26) to the outside thereof.

8. The mechanical compaction and grouting construction method for treating sediment at the bottom of a bored pile according to claim 7, characterized in that: A flexible sealing sleeve (11) is provided at one end of the vertical grouting telescopic pipe (8) close to the vertical grouting pipe (7); the lower end of the vertical grouting pipe (7) is slidably inserted into the upper end of the vertical grouting telescopic pipe (8); the inner side wall of the upper end of the flexible sealing sleeve (11) is tightly sealed on the outer side wall of the vertical grouting pipe (7); and the flexible sealing sleeve (11) and the vertical grouting pipe (7) are slidable along the axial direction.

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