Conical bag grouting and jacking device for multi-layer raft foundation building and construction method

Abstract

The invention discloses a conical bag grouting and jacking device for a multi-layer raft foundation building and a construction method. The conical bag grouting and jacking device comprises miniature steel pipe piles, a cross beam, conical bags and grouting pipes, a working ditch is pre-dug in the side, with large sedimentation, of the building, and the miniature steel pipe piles are inserted into the working ditch and connected together through connecting beams; horizontal holes are formed in the bottom of a building, a conical bag grouting device is inserted into each horizontal hole, each conical bag grouting device comprises a conical bag and a grouting pipe, the grouting pipes are inserted into the conical bags, the two ends of each conical bag are sealed, a plurality of grout outlets are formed in the grouting pipes, and the grouting pipes are connected with the conical bags. Grouting is conducted on the interior of the conical bag; the large-diameter end of the conical bag is located at the large-settlement bottom of the building, and the small-diameter end of the conical bag is located at the small-settlement bottom of the building.

Description

Technical Field

[0001] The invention relates to the technical field of foundation treatment engineering, and in particular to a stepped grouting device and a construction method for deviation correction construction of multi-layer and raft foundation buildings. Background Art

[0002] In the field of construction, due to the influence of environmental changes and geological disasters, existing buildings may sometimes be greatly affected, such as foundation settlement caused by earthquakes, and the decrease in foundation bearing capacity caused by heavy rainfall. These are the main factors that cause building tilts. If they are not properly handled, they will cause significant losses to the lives and property of residents.

[0003] The jacking method is a more commonly used construction method in deviation correction construction. It is often used in the deviation correction construction of multi-layer raft foundation buildings. Its construction method is to use technical measures to raise the foundation or structure on the side of the inclined building with greater settlement to achieve the purpose of deviation correction. It has the advantages of good controllability and high security.

[0004] There are many influencing factors in the construction process of the correction project, and the technical difficulty is relatively high. Patent CN104763004A discloses a method for correcting the deviation of a ground-based building, including 1. drilling a hole on the side opposite to the inclination direction of the building; 2. inserting a semicircular pipe wall into the vertical scouring hole, and inserting a circular pipe wall into the oblique drainage hole; 3. injecting high-pressure water to flush the soil under the foundation of the building to soften it and partially form mud, and then extending the stirring head equipped with a spray head laterally toward the foundation soil, and starting the motor after extending it to rotate the stirring head, stir the soil, cooperate with the spray head to accelerate the formation of mud, and discharge it from the oblique drainage hole; 4. After the building is gradually corrected, use a pump to insert a pumping pipe into the oblique drainage hole to drain the mud in the hole; 5. Inject a slurry-state soft soil curing agent into the drainage pipe to solidify the foundation soil; 6. Finally, pour cement slurry to seal the hole.

[0005] Although this method can quickly correct the deviation of the building, it fails to take into account the different lifting amounts in different areas, and needs to be comprehensively controlled. The existing correction construction methods are mostly high-pressure grouting, which lifts and lowers the building through grouting pressure. It is difficult to control the recovery amount, and there is a possibility of subsequent settlement. Therefore, it is necessary to propose a grouting device and construction method that can perform grouting correction in different areas and has the benefit of strengthening the stratum. Summary of the invention

[0006] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a conical bag grouting jacking device and a construction method for a multi-layer raft foundation building under different geological conditions.

[0007] In order to achieve the above object, the technical solution adopted in the present invention is as follows:

[0008] In the first aspect, a conical bag grouting jacking device for a multi-layer raft foundation building comprises micro steel pipe piles, a cross beam, a conical bag, and a grouting pipe. A working trench is pre-dug on the side of the building where the settlement is larger, the micro steel pipe piles are inserted in the working trench, and the micro steel pipe piles are connected together by connecting beams; horizontal holes are drilled at the bottom of the building, and a conical bag grouting device is inserted in each horizontal hole, the conical bag grouting device comprises a conical bag and a grouting pipe, one end of the grouting pipe is inserted into the conical bag, and the other end extends to the outside of the conical bag, both ends of the conical bag are sealed, and a plurality of slurry outlets are provided on the grouting pipe to perform grouting into the inside of the conical bag; the large diameter end of the conical bag is located at the bottom of the building where the settlement is larger, and the small diameter end is located at the bottom of the building where the settlement is smaller.

[0009] As a further technical solution, the horizontal holes are arranged in two rows, the upper and lower rows of horizontal holes being arranged in a plum blossom shape.

[0010] As a further technical solution, each slurry outlet is provided with a check valve.

[0011] As a further technical solution, the conical bladder has a set expansion amount.

[0012] As a further technical solution, the maximum diameter of the expanded conical bag is greater than or equal to the maximum inclination of the building.

[0013] As a further technical solution, the conical bag grouting device is arranged along the length direction or width direction of the bottom of the building.

[0014] As a further technical solution, the conical bag and the grouting pipe are buried together in the lower part of the building as a part of the bottom stratum of the building to support the building.

[0015] In a second aspect, the present invention also provides a construction method for a conical bag grouting jacking device for a multi-layer raft foundation building, which is as follows:

[0016] Step 1: Investigate the project conditions, clarify the tilt parameters, and obtain the maximum tilt H of the building.

[0017] Step 2: Pre-dig a working trench on the side of the building with greater settlement according to the construction specifications, and do a good job of pit wall support and reinforcement;

[0018] Step 3: After the excavation of the working trench is completed, grouting reinforcement is performed on the lower stratum of the building in advance to ensure that the bearing capacity of the reinforced stratum is greater than 1.2 times the upper building load;

[0019] Step 4: Drive multiple rows of micro steel pipe piles near the building foundation side of the working trench to ensure the stability of the working trench wall;

[0020] Step 5: Drill double rows of horizontal holes in a plum blossom shape at the bottom of the inclined building, and then carry out the grouting bag and grouting pipe construction. The construction sequence is first carried out on the lower row, and then cement mortar is injected into the upper row of grouting pipes through the grouting machine to complete the building jacking work;

[0021] Step 6: After the grouting process is completed, an I-beam cross (waist) beam is installed under the conical bag and anti-corrosion treatment is done, and it is connected to the micro steel pipe piles on the pit wall to ensure support;

[0022] Step 8: Backfill the working trench and restore the ground.

[0023] As a further technical solution, the grouting pressure F satisfies the formula:

[0024] F=P / Sδ

[0025] P is the total load of the building, S is the cross-sectional area of ​​the bag, and δ is the grouting loss coefficient, which can be taken as 1.2-1.5 based on construction experience.

[0026] As a further technical solution, the pipe withdrawal grouting method is adopted for grouting operations, and the grouting work is dynamically monitored to ensure the grouting efficiency.

[0027] Beneficial effects of the present invention:

[0028] The present invention proposes to use a conical bag for jacking grouting. Through the multi-chamber segmented grouting design, it can effectively lift the inclined building on one side, and the construction process is relatively convenient to operate, and will not cause significant damage to the service life of the building structure; and after the jacking is completed, the conical bag is left at the bottom of the building, and its main grouting pipe curtain can play a horizontal supporting effect, and the comprehensive effect with the previous grouting and jacking grouting can ensure the reliability of the jacking quality, and can avoid re-settlement to a great extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0030] Figure 1 A schematic diagram of the three-dimensional structure of the conical grouting bag proposed by the present invention;

[0031] Figure 2 The inner section of the conical grouting bag proposed by the present invention Figure 1 ;

[0032] Figure 3 The inner section of the conical grouting bag proposed by the present invention Figure 2 ;

[0033] Figure 4 This is a schematic diagram of the use state of the conical grouting bag proposed by the present invention during jacking;

[0034] Figure 5 This is a schematic diagram of the arrangement position of the device proposed by the present invention;

[0035] In the figure: 1. grouting pipe, 2. conical bag, 3. grout outlet, 4. working pit, 5. micro steel pipe pile, 6. beam, 7. upper structure. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise explicitly stated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof;

[0038] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0039] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0040] The present embodiment proposes a conical bag grouting jacking device for a multi-layer raft foundation building, comprising micro steel pipe piles, cross beams, conical bags, and grouting pipes. A working trench is pre-dug on the side of the building with greater settlement, and the micro steel pipe piles are inserted in the working trench, and the micro steel pipe piles are connected together by connecting beams; horizontal holes are drilled at the bottom of the building, and a conical bag grouting device is inserted in each horizontal hole, the conical bag grouting device comprises a conical bag and a grouting pipe, one end of the grouting pipe is inserted into the conical bag, and the other end extends to the outside of the conical bag, both ends of the conical bag are sealed, and a plurality of slurry outlets are provided on the grouting pipe to perform grouting into the inside of the conical bag; the large-diameter end of the conical bag is located at the bottom of the building with greater settlement, and the small-diameter end is located at the bottom of the building with less settlement.

[0041] As a further technical solution, the horizontal holes are arranged in two rows, the upper and lower rows of horizontal holes being arranged in a plum blossom shape.

[0042] As a further technical solution, each slurry outlet is provided with a check valve; that is, a plurality of slurry outlet holes are provided on the grouting pipe, and grout is injected into the internal cavity of the bag through the slurry outlets, and a check valve is provided inside to prevent the slurry from flowing back.

[0043] As a further technical solution, the conical bag has a set expansion amount; specifically, the bag is designed to have a set expansion amount H x , lifting correction coefficient γ, distance from the rear end of the lifting bag x, bag length l, bag grouting lifting h. The expected lifting amount of the bag with different jacking amount can be calculated using the formula

[0044]

[0045] The soil uplift coefficient is shown in Table 1.

[0046] Table 1 Lifting correction factor

[0047]

[0048] Furthermore, the maximum diameter of the expanded conical bag is greater than or equal to the maximum inclination of the building; the conical bag grouting device is arranged along the length direction or width direction of the bottom of the building; the front is narrow and the back is wide (conical) and it is suitable for construction environments with large unilateral settlement of the building, and it is arranged according to different values ​​under different geological conditions. The conical bag is buried in the lower part of the building, as part of the stratum at the bottom of the building, to support the building.

[0049] Furthermore, a grouting pipe is used to perform grouting operations into the interior of the bag. The length of the pipe is set to 2 / 3 of the existing structure width, and the pipe material selection range is 48-108 steel pipe.

[0050] Further, the stepped conical bag grouting device for multi-story building correction proposed in this embodiment (attached Figure 1 ), including a grouting pipe 1 inside the device, a conical grouting bag 2 installed on the outer wall of the grouting pipe, a grouting outlet 3, a working pit 4, a micro steel pipe pile 5, a crossbeam 6, an upper structure 7, etc. The specific construction method is as follows:

[0051] Step 1: Investigate the project conditions, clarify the tilt parameters, and obtain the maximum tilt amount H.

[0052] Step 2: First, dig a working trench on the side of the building where settlement is greater according to construction specifications, and do a good job of supporting and reinforcing the pit wall.

[0053] Step 3: After the excavation of the working trench is completed, grouting reinforcement is performed on the ground below the structure to ensure that the bearing capacity of the reinforced ground is greater than 1.2 times the upper building load;

[0054] Step 4: Drive multiple rows of micro steel pipe piles on the structure side of the working trench to ensure the stability of the working trench wall.

[0055] Step 5: Drill double rows of horizontal holes in a plum blossom-shaped arrangement in the reinforced stratum at the bottom of the inclined building, with a borehole diameter of 110 mm and a horizontal hole spacing of 0.3 m to 0.8 m, and a height difference of 0.3 m to 0.5 m between the borehole center and the raft foundation. Then, the conical bag and grouting pipe are constructed, and the conical bag grouting device is placed in the horizontal hole, and then grouting is performed;

[0056] The construction sequence is to prioritize the lower row, and the depth of the double-row grouting pipe ends is about 2 / 3 of the building width or length; then the grouting machine is used to inject cement mortar into the upper row of grouting pipes, and the grouting pressure F satisfies the formula:

[0057] F=P / Sδ(2)

[0058] Among them, P is the total load of the building, S is the cross-sectional area of ​​the bag, and δ is the grouting loss coefficient, which can be taken as 1.2-1.5 based on construction experience.

[0059] Furthermore, different grouting methods are selected according to different strata. For example, the retreat grouting method can be adopted for grouting operations; that is, the grouting pipe of the external grouting device is inserted into the grouting pipe of the conical bag grouting device, and then the grouting is performed in reverse sections from the small diameter end to the large diameter end of the conical bag, and a check valve is provided in the slurry outlet to prevent the slurry from flowing back.

[0060] Step 6: Simultaneously, dynamically monitor the grouting work to ensure grouting efficiency.

[0061] Step 7: After the grouting process is completed, an I-beam horizontal (waist) beam is installed under the grouting pipe and anti-corrosion treatment is done, and it is connected to the pit wall micro steel pipe pile (with a diameter of 200-300 and cement mortar or fine stone concrete poured in it, and the main body of the steel pipe is a seamless steel pipe) to ensure support; and the conical bag of the conical bag grouting device and the grouting pipe inside the conical bag are buried in the stratum to support the building together;

[0062] Step 8: Backfill the working trench and restore the ground.

[0063] The present embodiment proposes to use a conical bag for jacking grouting. Through the multi-chamber segmented grouting design, it is possible to effectively lift an inclined building on one side, and the construction process is relatively convenient to operate without causing significant damage to the service life of the building structure. After the jacking is completed, the conical bag is left at the bottom of the building, and its main grouting pipe curtain can play a horizontal supporting role, and the combined effect of the previous grouting and jacking grouting can ensure the reliability of the jacking quality and avoid re-settlement to a great extent.

[0064] This embodiment provides a stepped bag-type grouting pipe for multi-story buildings with large single-sided settlement. Through the multi-chamber segmented grouting design, it can effectively lift the inclined building on one side, and the construction process is relatively convenient to operate without causing significant damage to the service life of the building structure.

[0065] The design size of the conical bag in this embodiment can be designed according to different formation conditions by taking corresponding jacking empirical coefficients, and a formula for the expected lifting amount of the bag with different jacking amounts is proposed: Ensure construction safety and efficiency of building correction construction.

[0066] In the plum blossom-shaped double-row pipe arrangement of this embodiment, the lower pipe curtain is constructed first, which can provide a stratum pre-reinforcement effect for the upper row construction, thereby ensuring the safety of the construction and the stability of the project.

[0067] The above description is only a preferred embodiment of the present invention; it is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Conical bag grouting jacking device for multi-layer raft foundation building, characterized in that: It comprises micro steel pipe piles, cross beams, conical bags and grouting pipes. A working trench is pre-dug on the side of a building with greater settlement. The micro steel pipe piles are inserted in the working trench and connected together by connecting beams. Horizontal holes are drilled at the bottom of the building. A conical bag grouting device is inserted in each horizontal hole. The conical bag grouting device comprises a conical bag and a grouting pipe. One end of the grouting pipe is inserted into the conical bag and the other end extends out of the conical bag. Both ends of the conical bag are sealed. A plurality of slurry outlets are arranged on the grouting pipe to grout into the conical bag. The large-diameter end of the conical bag is located at the bottom of the building with greater settlement, and the small-diameter end is located at the bottom of the building with less settlement.

2. The conical bag grouting jacking device for a multi-layer raft foundation building according to claim 1, characterized in that: The horizontal holes are arranged in two upper and lower rows, and the upper and lower rows of horizontal holes are arranged in a plum blossom shape.

3. The conical bag grouting jacking device for a multi-layer raft foundation building according to claim 1, characterized in that: Each slurry outlet is provided with a check valve.

4. The conical bag grouting jacking device for a multi-layer raft foundation building according to claim 1, characterized in that: The conical bladder has a set expansion amount.

5. The conical bag grouting jacking device for a multi-layer raft foundation building according to claim 1, characterized in that: The maximum diameter of the expanded conical bag is greater than or equal to the maximum inclination of the building.

6. The conical bag grouting jacking device for a multi-layer raft foundation building according to claim 1, characterized in that: The conical bag grouting device is arranged along the length direction or the width direction of the bottom of the building.

7. The conical bag grouting jacking device for a multi-layer raft foundation building according to claim 1, characterized in that: The conical bag and the grouting pipe are buried together in the lower part of the building as a part of the bottom stratum of the building to support the building.

8. A construction method for a conical bag grouting and jacking device for a multi-layer raft foundation building according to any one of claims 1 to 7, characterized in that: The details are as follows: Step 1: Investigate the project conditions, clarify the tilt parameters, and obtain the maximum tilt H of the building. Step 2: Pre-dig a working trench on the side of the building with greater settlement according to the construction specifications, and do a good job of pit wall support and reinforcement; Step 3: After the excavation of the working trench is completed, grouting reinforcement is performed on the lower stratum of the building in advance to ensure that the bearing capacity of the reinforced stratum is greater than 1.2 times the upper building load; Step 4: Drive multiple rows of micro steel pipe piles near the building foundation side of the working trench to ensure the stability of the working trench wall; Step 5: Drill double rows of horizontal holes in the reinforced stratum at the bottom of the inclined building in a plum blossom shape, and then carry out the grouting bag and grouting pipe construction. The construction sequence is first carried out on the lower row, and then cement mortar is injected into the upper row of grouting pipes through the grouting machine to complete the building jacking work; Step 6: After the grouting process is completed, an I-beam beam is installed under the conical bag and anti-corrosion treatment is done, and it is connected to the micro steel pipe piles on the pit wall to ensure support; Step 8: Backfill the working trench and restore the ground.

9. The construction method of the multi-layer raft foundation building conical bag grouting jacking device as claimed in claim 8, characterized in that: The grouting pressure F satisfies the formula; F=P / Sδ P is the total load of the building, S is the cross-sectional area of ​​the bag, and δ is the grouting loss coefficient, which can be taken as 1.2-1.5 based on construction experience.

10. The construction method of the conical bag grouting jacking device for a multi-layer raft foundation building as described in claim 8 adopts the pipe-retracting grouting method to carry out the grouting operation, and at the same time dynamically monitors the grouting work to ensure the grouting efficiency.

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