Directional full high-pressure guniting supporting system and construction method

Abstract

The invention belongs to the technical field of foundation pit supporting, and particularly relates to a directional full high-pressure guniting supporting system and a construction method.The directional full high-pressure guniting supporting system comprises a pile driver, a hole-forming grouting plate, stirring pulping equipment and slurry supply equipment, the hole-forming grouting plate comprises a long-strip-shaped body, a grouting hole is formed in one side of the body, and an engagement structure matched with the grouting hole is arranged on the other side of the body; the adjacent hole-forming grouting plates are connected in an embedded mode through the meshing structures and the grouting holes when driven in, the pile driver is used for driving the hole-forming grouting plates into the preset depth of a foundation pit design supporting area, the stirring and slurrying equipment is used for preparing cement slurry, the slurry supply equipment is a grouting machine, and the stirring and slurrying equipment is connected with the grouting machine. The construction method has the beneficial effects that the pore-forming grouting plate plays a temporary supporting role, and the cement soil plays a long-term protection role; grouting is carried out while the hole-forming grouting plate is slowly pulled out, gaps are filled with grout, the grout and surrounding soil are solidified to form a grout soil solidification pile, and the bottom of the foundation pit is effectively prevented from protruding.

Description

Technical Field

[0001] This invention relates to the field of foundation pit support technology, specifically to a directional full-span high-pressure shotcrete support system and construction method. Background Technology

[0002] With the rapid development of urban construction, construction projects near subways or other important structures are increasing, placing extremely high demands on the safety and stability of foundation pit support. During foundation pit excavation, earthwork excavation and soil unloading can easily cause the bottom of the foundation pit to heave, affecting the construction safety of the foundation pit itself. If an elevated bridge is being constructed within 10 meters of a subway station, the excavation of the foundation pit will cause unloading of the soil around the subway, easily leading to displacement of the subway tunnel. Meanwhile, the elevated bridge, columns, foundations, and other structures being constructed within the foundation pit will transfer the load downwards, causing the soil under the foundation to be squeezed outwards, creating lateral pressure on the subway tunnel, further causing displacement and deformation of the subway tunnel, posing a serious engineering safety hazard.

[0003] Current foundation pit support technologies are unable to simultaneously address the issues of foundation pit bottom heave and interference with surrounding important structures. There is a lack of a targeted and controllable support method, which fails to meet the foundation pit construction needs of nearby important structures. Summary of the Invention

[0004] The present invention addresses the problems mentioned above by designing a directional full-span high-pressure shotcrete support system and construction method to overcome the deficiencies of the existing technology.

[0005] To achieve the above objectives, the present invention provides a directional full-span high-pressure shotcrete support system, comprising a pile driver, a hole-forming grouting plate, a mixing and grouting equipment, and a grouting supply equipment. The hole-forming grouting plate comprises a body, with a grouting hole on one side and an interlocking structure adapted to the grouting hole on the other side. When adjacent hole-forming grouting plates are driven in, they interlock with each other through the interlocking structure and the grouting hole. The pile driver is used to drive the hole-forming grouting plate into a preset depth in the designed support area of ​​the foundation pit. The mixing and grouting equipment is used to prepare cement grout. The grouting supply equipment is a grouting machine. The mixing and grouting equipment is connected to the grouting machine and is used to inject the prepared cement grout into the ground under high pressure through the grouting hole.

[0006] Furthermore, the top of the interlocking structure has multiple sets of axial transition grooves arranged in a circumferential array, and the axial transition grooves are connected to stepped slots. The grouting hole is flexibly engaged with the interlocking structure by elastic claws.

[0007] Furthermore, the top of the grouting hole has multiple sets of axial blind holes in a circumferential array, and one end of the elastic claw is flexibly inserted into the axial blind hole. The elastic claw includes a spring and a limiting post. One end of the limiting post has an axial blind hole and the other end is fixedly connected to a locking protrusion. The two ends of the spring are respectively fixed inside the axial blind hole and the axial blind hole.

[0008] Furthermore, parallel double guide rails are laid inside the axial blind hole, the limiting post is slidably connected to the double guide rails through a slider group, and the guiding end of the double guide rails is fixedly connected to a limiting plate.

[0009] Furthermore, the mixing and pulping equipment is a twin-shaft forced mixer, a ribbon mixer, a pneumatic mixer, a paddle mixer, or a turbine mixer.

[0010] Furthermore, the grouting machine is a pneumatically driven, hydraulically pumped, or rotor-type structure.

[0011] This invention also includes a construction method for a directional full-span high-pressure shotcrete support system, comprising the following steps: Step 1: Use a pile driver to drive the grouting plate into the pre-set depth of the foundation pit's designed support area. Within the enclosure of the grouting plate, complete the foundation pit excavation and structure construction, which serves as temporary support. Step 2: Prepare cement slurry using a mixing and pulping equipment; Step 3: High-pressure grouting. Connect the mixing and grouting equipment to the grouting machine. Inject the prepared grout through the grouting holes of the grouting plate through the pipeline. The grout is then sprayed into the ground under high pressure through the lower end of the grouting holes. At the same time as grouting, slowly pull out the grouting plate. Step 4: After the single hole grouting plate is removed and grouted, repeat the operation of Step 3 for the remaining hole grouting plates in sequence until the construction of all hole grouting plates in the designed support area is completed.

[0012] Furthermore, in step one, multiple perforated grouting plates are interlocked to form a continuous integral enclosure. The grouting holes are directly inserted into the interlocking structure or obliquely inserted at a certain angle, and the height of the perforated grouting plate protruding above the ground is not less than 300mm.

[0013] Furthermore, in step three, during the grouting process, the grouting rate is controlled at 10-100 L / min, the grouting pressure is maintained at 0.5-4.5 MPa, and the grout is cured for 24-72 hours after being injected into the soil.

[0014] Furthermore, in step three, when a continuous and stable grouting occurs on the ground, it is determined that the grouting point has achieved the grouting effect, and the grouting operation is terminated.

[0015] In summary, the present invention has the following advantages and beneficial technical effects: 1. This invention combines the directional installation of grouting plates with high-pressure jet grouting. When the grouting plates are pulled out, the grout simultaneously fills the gaps and consolidates with the surrounding soil to form grout-soil consolidation piles. This effectively suppresses the bottom heave of the foundation pit, improves the safety of the foundation pit construction, and takes into account both temporary support and long-term protection.

[0016] 2. The construction method of this invention has controllable parameters. The grouting rate, pressure, and mix ratio can all be adjusted according to the soil properties. The construction operation is simple and the support effect is stable. It is suitable for various complex foundation pit support construction scenarios such as urban overpasses crossing existing rail transit and adjacent large buildings.

[0017] 3. In this invention, the perforated grouting plate has a built-in interlocking structure. When driven in, the perforated grouting plate can be interlocked with the grouting hole through the interlocking structure to form a continuous whole, which makes the support effect more stable. Multiple perforated grouting plates can be inserted straight or obliquely at a certain angle. The oblique insertion can flexibly enclose the contour of irregular foundation pits, reduce the amount of plate used, and improve the overall integrity of the enclosure.

[0018] 4. In this invention, the stepped groove restricts the circumferential and axial movement of the locking protrusion, ensuring a reliable overall connection after the adjacent grouting plates are directly inserted.

[0019] 5. In this invention, the double guide rails cooperate with the slider assembly to ensure that the elastic claws only extend and retract stably in the radial direction, avoiding shaking and skewing; the limiting plate is used to prevent the slider assembly from derailing; the spring provides a continuous radial clamping force, so that the snap-fit ​​protrusion is always tightly fitted with the stepped snap-fit ​​groove, realizing the flexible snap-fit, self-adaptive alignment and vibration damping of the grouting hole and the interlocking structure. Attached Figure Description

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a construction flowchart of the present invention; Figure 2 This is a top view schematic diagram of the grouting plate in this invention; Figure 3 This is a three-dimensional schematic diagram of the grouting plate used in this invention; Figure 4 This is a schematic diagram of the top of the interlocking structure in this invention; Figure 5 This is a schematic diagram of the structure at the top of the grouting hole in this invention; Figure 6 This is a cross-sectional schematic diagram of the grouting hole in this invention; Figure 7 This is a cross-sectional schematic diagram of the elastic claw in this invention; Figure 8 This is a three-dimensional schematic diagram of the elastic claw in this invention; Figure 9 This is a schematic diagram of the assembly of the grouting hole and the interlocking structure when adjacent grouting plates are inserted directly.

[0021] The reference numerals in the attached figures are: 1. Body; 2. Grouting hole; 3. Interlocking structure; 4. Axial transition groove; 5. Stepped slot; 6. Axial blind hole one; 7. Limiting post; 8. Spring; 9. Snap-fit ​​protrusion; 10. Double guide rail; 11. Slider group; 12. Limiting plate. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout; the described embodiments are some embodiments of this invention, but not all embodiments; the embodiments and directional terms described below with reference to the accompanying drawings are exemplary and intended to explain this invention, and should not be construed as limiting this invention; all other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The embodiments of this invention will be described in detail below with reference to the accompanying drawings: The following is in conjunction with the appendix Figures 1-9 The present invention will be further described in detail below: Example 1 like Figure 2 As shown, this embodiment discloses a directional full-span high-pressure shotcrete support system, including a pile driver, a hole-forming grouting plate, a mixing and grouting equipment, and a grouting supply equipment. The hole-forming grouting plate includes a body 1, with a grouting hole 2 fixed on one side and an interlocking structure 3 fixedly connected to the other side. The grouting hole 2 extends vertically through the body 1, with a grouting interface at the upper end and a high-pressure grout outlet at the lower end. The interlocking structure 3 matches and aligns with the grouting hole 2. When adjacent hole-forming grouting plates are driven in, they interlock with each other through the interlocking structure 3 to form a continuous integral retaining structure. The pile driver is used to drive the hole-forming grouting plate into the preset depth of the designed support area of ​​the foundation pit. The mixing and grouting equipment is used to prepare cement grout. The grouting supply equipment is a grouting machine. The mixing and grouting equipment is connected to the grouting machine and is used to inject the prepared cement grout into the ground under high pressure through the grouting hole 2. The preferred mixing and grouting equipment includes a twin-shaft forced mixer, a ribbon mixer, a pneumatic mixer, a paddle mixer, and a turbine mixer. Grouting machines are preferably pneumatically driven, hydraulically pumped, or rotor-type structures.

[0023] In this embodiment, the body 1 is a long strip steel plate. The body 1 can be an existing Larssen steel sheet pile, H-shaped steel sheet pile or Z-shaped steel sheet pile. When Larssen steel sheet pile, H-shaped steel sheet pile or Z-shaped steel sheet pile is used, the grouting hole 2 and the interlocking structure 3 are symmetrically arranged on the flanges on both sides of the steel sheet pile.

[0024] Example 2 The difference between this embodiment and Embodiment 1 is that: Figures 3-5 As shown, in this embodiment, the top of the interlocking structure 3 has two sets of axial transition grooves 4 arranged in a circumferential array, and the axial transition grooves 4 are connected to a stepped groove 5 with a radial opening. The grouting hole 2 is flexibly engaged with the interlocking structure 3 by elastic claws. The outer wall of the grouting hole 2 has two sets of axial blind holes 6 arranged in a circumferential array, and elastic claws are installed in the axial blind holes 6.

[0025] like Figures 6-8 As shown, the elastic claw includes a spring 8, a limiting post 7, and a locking protrusion 9. One end of the limiting post 7 has an axial blind hole two, and the locking protrusion 9 is fixed to the other end of the limiting post 7. Both ends of the spring 8 are fixed within the axial blind hole one 6 and the axial blind hole two, respectively. Parallel double guide rails 10 are laid within the axial blind hole one 6. The limiting post 7 is slidably connected to the double guide rails 10 via a slider assembly 11. A limiting plate 12 is fixed to the guide end of the double guide rails 10 to prevent the slider assembly 11 from derailing.

[0026] like Figure 9 As shown, when adjacent grouting plates are inserted directly, the elastic claws slide in through the axial transition groove 4. The locking protrusion 9 is squeezed by the inner wall of the interlocking structure 3, causing the limiting post 7 to retract radially inward along the double guide rail 10 and compress the spring 8 until the locking protrusion 9 is locked in the stepped groove 5 to achieve automatic locking. In this embodiment, the outer diameter of the grouting hole 2 is smaller than the inner diameter of the interlocking structure 3, ensuring that the grouting hole 2 and the interlocking structure 3 can be smoothly inserted and that the elastic claws can extend and retract normally to lock, avoiding assembly interference.

[0027] Example 3 like Figure 1 As shown, the construction method of a directional full-span high-pressure shotcrete support system of the present invention is as follows: Step 1: Using a pile driver, drive the grouting plate into the pre-set depth of the designed support area of ​​the foundation pit. The height of the grouting plate protruding above the ground should not be less than 300mm to reserve operating space for subsequent grouting operations. The driving angle of the grouting plate can be adjusted according to the design requirements of the foundation pit retaining structure. Multiple grouting plates are inserted straight or obliquely at the design angle to form a closed retaining structure. After the foundation pit excavation and structure construction are completed within the retaining area of ​​the grouting plate, grouting operations need to be prepared to prevent soil deformation. This is to prevent the pores from collapsing after the grouting plate is pulled out and to prevent the lateral pressure on the structures outside the grouting plate area after the construction structure sinks.

[0028] Step 2: Prepare cement slurry using a mixing and slurry preparation device.

[0029] Step 3: High-pressure grouting. Connect the mixing and grouting equipment to the grouting machine. Inject the prepared grout through the grouting hole 2 of the grouting plate via a pipeline. The grout is then sprayed into the ground under high pressure through the grout outlet at the lower end of the grouting hole 2. While grouting, the grouting plate is slowly pulled out. During the pulling process, the grout quickly fills the soil voids formed after the grouting plate is pulled out, preventing the voids from collapsing and causing soil displacement. On the other hand, under the grouting pressure, the cement grout is forced into the surrounding soil, and after being fully mixed with the soil, it solidifies to form grout-soil consolidated piles. The grout-soil consolidated piles are interconnected to form an integral support structure, enhancing the stability of the foundation pit soil. During the grouting process, the grouting rate is controlled at 10-100L / min, the grouting pressure is maintained at 0.5-4.5MPa, and the grout is cured for 24h-72h after being injected into the soil to ensure that the grout and soil are fully consolidated. When a continuous and stable grout seepage occurs on the ground, it is determined that the grouting point has achieved the desired grouting effect, and the grouting operation is terminated.

[0030] Step 4: After the single hole grouting plate is removed and grouted, repeat the operation of Step 3 for the remaining hole grouting plates in sequence until the construction of all hole grouting plates in the designed support area is completed.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A directional full-span high-pressure shotcrete support system, characterized in that: The system includes a piling machine, a grouting plate, a mixing and grouting equipment, and a grouting supply equipment. The grouting plate includes a body with a grouting hole on one side and an interlocking structure adapted to the grouting hole on the other side. When adjacent grouting plates are driven in, they interlock with each other through the interlocking structure and the grouting hole. The piling machine is used to drive the grouting plate into the preset depth of the foundation pit's designed support area. The mixing and grouting equipment is used to prepare cement grout. The grouting supply equipment is a grouting machine. The mixing and grouting equipment is connected to the grouting machine and is used to inject the prepared cement grout into the ground under high pressure through the grouting hole.

2. The directional full-span high-pressure shotcrete support system according to claim 1, characterized in that: The top of the interlocking structure has multiple sets of axial transition grooves arranged in a circumferential array. The axial transition grooves are connected to stepped slots. The grouting hole is flexibly engaged with the interlocking structure by elastic claws.

3. The directional full-span high-pressure shotcrete support system according to claim 2, characterized in that: The top of the grouting hole is provided with multiple sets of axial blind holes in a circumferential array. One end of the elastic claw is flexibly inserted into the axial blind hole. The elastic claw includes a spring and a limiting post. One end of the limiting post is provided with an axial blind hole and the other end is fixedly connected to a snap-fit ​​protrusion. The two ends of the spring are respectively fixed inside the axial blind hole and the axial blind hole.

4. The directional full-span high-pressure shotcrete support system according to claim 3, characterized in that: Parallel double guide rails are laid inside the axial blind hole. The limiting post is slidably connected to the double guide rails through a slider group, and the guiding end of the double guide rails is fixedly connected to a limiting plate.

5. A directional full-span high-pressure shotcrete support system according to claim 1, characterized in that: The mixing and pulping equipment is a twin-shaft forced mixer, a ribbon mixer, a pneumatic mixer, a paddle mixer, or a turbine mixer.

6. The directional full-span high-pressure shotcrete support system according to claim 1, characterized in that: The grouting machine can be pneumatically driven, hydraulically pumped, or rotor-type.

7. A construction method for a directional full-span high-pressure shotcrete support system, characterized in that: The construction method of the directional full-span high-pressure shotcrete support system according to claim 1 includes the following steps: Step 1: Use a pile driver to drive the grouting plate into the pre-set depth of the foundation pit's designed support area. Within the enclosure of the grouting plate, complete the foundation pit excavation and structure construction, which serves as temporary support. Step 2: Prepare cement slurry using a mixing and pulping equipment; Step 3: High-pressure grouting. Connect the mixing and grouting equipment to the grouting machine. Inject the prepared grout through the grouting holes of the grouting plate through the pipeline. The grout is then sprayed into the ground under high pressure through the lower end of the grouting holes. At the same time as grouting, slowly pull out the grouting plate. Step 4: After the single hole grouting plate is removed and grouted, repeat the operation of Step 3 for the remaining hole grouting plates in sequence until the construction of all hole grouting plates in the designed support area is completed.

8. The construction method of a directional full-span high-pressure shotcrete support system according to claim 7, characterized in that: In step one, multiple perforated grouting plates are interlocked to form a continuous integral enclosure. The grouting holes are directly inserted into the interlocking structure or obliquely inserted at a certain angle, and the height of the perforated grouting plate protruding above the ground is not less than 300mm.

9. A construction method for a directional full-span high-pressure shotcrete support system according to claim 7, characterized in that: In step three, during the grouting process, the grouting rate is controlled at 10-100 L / min, the grouting pressure is maintained at 0.5-4.5 MPa, and the grout is cured for 24-72 hours after being injected into the soil.

10. A construction method for a directional full-span high-pressure shotcrete support system according to claim 9, characterized in that: In step three, when a continuous and stable grouting occurs on the ground, it is determined that the grouting point has achieved the grouting effect, and the grouting operation is terminated.

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