A building tilt correction and sinking acceleration device and construction method

Abstract

The invention relates to a device for correcting the tilt and promoting the sinking of a building and a construction method, comprising a building foundation and an anchor cable. A borehole is drilled in the building foundation, and the borehole sequentially passes through a sand and gravel layer and a bedrock layer in a foundation at the bottom of the building foundation; one end of the anchor cable is inserted into the borehole and fixed with cement slurry, and the other end is located outside the building foundation and tensioned and locked with a working anchor; the beneficial effects of the invention are: 1. There is no need to excavate a vertical shaft on the building foundation and in the foundation, so the damage to the foundation is minimized and the interference to the foundation is minimized; the construction does not need to be carried out in a narrow space, the safety risk is low, and the operation is simple; 2. The drilled holes can be used as anchor cable holes or water-flushing correction holes. The anchor cable can play a role of pressurization during the tilt correction process, and can also play a role of anti-re-tilting reinforcement after the tilt correction is completed. One object has multiple uses, the construction period is short, and the cost is saved by about 30%.

Description

Technical Field

[0001] The invention belongs to the technical field of foundation engineering, and in particular relates to a device for correcting inclination and accelerating settlement of buildings on sand and gravel foundations and a construction method. Background Art

[0002] Many cities in my country are located on river valley terraces, and the foundations of buildings are usually located on gravel foundations. Due to the uneven thickness of gravel or the different thickness of silty soil under the gravel layer, the buildings usually tilt.

[0003] There are two traditional correction methods that are close to the present invention:

[0004] 1. Auxiliary well water jetting correction method: excavate several vertical shafts with a diameter of about 1.2m-1.5m on the foundation or edge of the less sunken side of the building, enter the foundation soil under the foundation, and the well depth is about 2m. The vertical shaft needs to be protected by a wall. Workers use high-pressure water guns to flush water horizontally in the well to wash away part of the soil in the soft stratum to achieve the purpose of forced landing and correction. After the correction is completed, the vertical shafts are backfilled one by one to restore the foundation reinforcement. This method is suitable for soft soil strata in the south.

[0005] 2. The horizontal radial excavation and anchor cable pressurization combined correction method is to dig several vertical shafts with a diameter of about 1.8m-2.5m on the foundation or edge of the less sinking side of the building, and enter the foundation soil under the foundation. The well depth needs to be about 2m below the bottom of the foundation. The vertical shaft needs to be protected by a protective wall. Place the drilling rig in the well and use the drilling rig to drill holes radially horizontally to excavate the soil. At the same time, a row of anchor cables are vertically driven into the outer protruding part of the foundation on the less sinking side of the building, and the anchor cables are used to pressurize the foundation to cause the less sinking side to settle, thereby achieving the purpose of correction.

[0006] The above two methods have successful cases in soft soil, silty soil and mudstone formations, but there are few successful cases of correcting inclination in sandy and gravel formations. In addition, they also have certain defects. Among them:

[0007] 1. Disadvantages of the auxiliary well water jetting method: 1. It is necessary to dig a larger diameter vertical shaft on the foundation or at the edge of the foundation, which destroys the integrity of the foundation and has a certain impact on the stress on the foundation; 2. The space in the well is limited, the workers' operating conditions are difficult, and there are safety hazards; 3. The accuracy of water jetting for forced landing is not high.

[0008] 2. Disadvantages of the combined correction method of horizontal radial excavation and anchor cable pressure: 1. It is also necessary to dig a larger diameter vertical shaft on the foundation or at the edge of the foundation, which destroys the integrity of the foundation and has an adverse effect on the stress on the foundation; 2. The space in the shaft is narrow, the drilling dust pollution is serious, and the operating conditions of the workers are poor; 3. Horizontal drilling in sandy and gravel strata has a high probability of hole collapse. If large boulders are encountered, correction is difficult; 4. Although anchor cable pressure can improve the accuracy of correction, the anchor cable hole has a single purpose. Summary of the invention

[0009] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a device for correcting inclination and accelerating settlement of buildings on sand and gravel foundations and a construction method.

[0010] The objective of the present invention is achieved through the following technical solution: a device for correcting inclination and promoting sinking of a building, comprising a building foundation and an anchor cable. A borehole is drilled on the building foundation, and the borehole sequentially passes through a sand and gravel layer and a bedrock layer in a foundation at the bottom of the building foundation; one end of the anchor cable is inserted into the borehole and fixed with cement slurry, and the other end is located outside the building foundation and is tensioned and locked with a working anchor.

[0011] Preferably, the building foundation is divided into a less-sinking side and a more-sinking side, and a pit is dug on the ground of the less-sinking side; the drill hole is located on the less-sinking side of the building foundation.

[0012] Preferably, a plurality of evenly arranged boreholes are drilled in the building foundation on the less-sunken side, and the distance between two adjacent boreholes is 3m.

[0013] Preferably, the borehole is divided into an anchoring section and a free section, the anchoring section is located in the bedrock layer of the foundation, and the free section is located in the sand and gravel layer of the foundation.

[0014] Preferably, the height of the anchoring section is 10 to 12 m.

[0015] Preferably, the diameter of the drilled hole is 140 to 160 mm.

[0016] A construction method using the building tilt correction and sinking acceleration device as described above, the tilt correction and sinking acceleration construction method comprises the following steps:

[0017] S1. Drill a row of vertical holes at the overhanging part of the foundation on the less sunken side of the building using a drilling rig until the holes are drilled into the bottom surface of the sand and gravel layer or the top surface of the bedrock layer;

[0018] S2. When reaching the top of the bedrock layer, stop drilling temporarily, inject water into the borehole, and use high-pressure air to flush it. In this way, the silty silt at the bottom of the sand and gravel layer is blown up by the high-pressure wind, and the less subsiding side of the building begins to settle, and the building begins to tilt back;

[0019] S3. When the building tilts back to a point close to the correction target, stop the water injection and air blowing operation, and continue to drill downwards with the drilling rig until the hole enters the bedrock layer for 12m;

[0020] S4. Insert the anchor cable into the borehole and start grouting, and control the cement slurry level not to exceed the top surface of the bedrock layer;

[0021] S5. When the anchor cable grouting reaches the age, the anchor cable is tensioned step by step through the jack. The force applied by the anchor cable can accelerate the settlement of the building foundation.

[0022] S6. If the anchor cable is loaded to the design load and the building still cannot tilt back to the target value, the anchor cable hole can be used to continue to inject water and blow air into the sand and gravel layer to disturb it. In this way, water injection and blowing air and anchor cable pressure are carried out alternately until the tilt correction target is achieved;

[0023] S7. After the tilt correction is completed, pressure grouting is performed on the drilled holes in the free section, and the cement slurry is used to fill the gaps in the sand and gravel layer after flushing. Finally, the anchor cable is tensioned and locked through the working anchor to play the role of anti-tilt reinforcement.

[0024] The beneficial effects of the present invention are: 1. There is no need to dig a vertical shaft on the building foundation and in the ground, so the damage to the foundation and the interference to the foundation are minimal; the construction does not need to be carried out in a narrow space, the safety risk is low, and the operation is simple; 2. The drilling holes can be used as anchor holes or water flushing correction holes. The anchor cables can play a role in pressurization during the correction process, and after the correction is completed, they can also play a role in preventing re-tilting and reinforcement. One thing has multiple uses, the construction period is short, and the cost is saved by about 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the water-flushing and air-blowing deviation-correcting structure of the inclination-correcting and sinking-promoting device of the present invention.

[0026] Figure 2 It is a schematic diagram of the anchor cable pressurized deviation correction structure of the inclination correction and sinking acceleration device of the present invention.

[0027] Figure 3 It is a schematic diagram of the anchor cable anti-re-tilt reinforcement structure of the tilt correcting and sinking accelerating device of the present invention.

[0028] The numbers in the attached drawings are: 1. building foundation; 2. anchor cable; 3. drill hole; 4. gravel layer; 5. bedrock layer; 6. cement slurry; 7. working anchor; 8. pit; 9. building; 10. jack; 11. less sinking side; 12. more sinking side; 31. anchoring section; 32. free section. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to the accompanying drawings: Figures 1 to 3As shown, the present invention comprises a building foundation 1 and an anchor cable 2. A borehole 3 is drilled on the building foundation 1. The borehole 3 is arranged vertically and passes through a gravel layer 4 and a bedrock layer 5 in the foundation at the bottom of the building foundation 1 in sequence. One end of the anchor cable 2 is inserted into the borehole 3 and fixed with cement slurry 6, and the other end is located outside the building foundation 1 and tensioned and locked with a working anchor 7. The advantages are: 1. There is no need to dig a vertical shaft on the building foundation and in the foundation, so the damage to the foundation is minimal and the interference to the foundation is minimal; the construction does not need to be operated in a narrow space, the safety risk is low, and the operation is simple; 2. The drilled hole can be used as an anchor cable hole or a flushing correction hole. The anchor cable can play a role of pressurization during the correction process, and after the correction is completed, it can also play a role of anti-re-tilt reinforcement. One object has multiple uses, the construction period is short, and the cost is saved by about 30%.

[0030] The building foundation 1 is divided into a less-sinking side 11 and a more-sinking side 12, and a pit 8 is dug on the ground of the less-sinking side 11, and the size of the pit 8 must be sufficient for construction workers to construct; the borehole 3 is located on the less-sinking side 11 on the building foundation 1, so that the anchor cable pressurization construction process and the water flushing and blowing correction process are put into the borehole 3, which can make the building have a tilt correction effect.

[0031] In order to ensure the stability of the building during the correction process and the uniformity of the force during the settlement of the less-settled side 11, a number of evenly arranged boreholes 3 are drilled on the building foundation 1 of the less-settled side 11, and the distance between two adjacent boreholes 3 is 3m.

[0032] The drilling is carried out in two steps, the first time the drilling is to the bottom of the gravel layer 4, and the second time the drilling is to 10 to 12 m inside the bedrock layer 5; the borehole 3 is divided into an anchoring section 31 and a free section 32, the anchoring section 31 is located in the bedrock layer 5 of the foundation, and plays an anchoring role together with the anchor cable and cement slurry; the free section 32 is located in the gravel layer 4 of the foundation, and, firstly, plays a function of correcting deviation by flushing and blowing air, and, secondly, plays a role of anti-tilting reinforcement together with the anchor cable and cement slurry.

[0033] The height of the anchoring section 31 is 10 to 12 m, with a preferred value of 10 m; the diameter of the borehole 3 is 140 to 160 mm, with a preferred value of 150 mm; this anchoring section 31 generally only requires 3.5 bags of cement to be filled with its preferred size, and together with the anchor cable, it plays an anchoring role and provides a pressurized reaction force for deviation correction.

[0034] A construction method using a building tilt correction and sinking acceleration device, the tilt correction and sinking acceleration construction method comprising the following steps:

[0035] S1. Drill a row of vertical holes 3 with a diameter of 150 mm at the overhanging part of the foundation on the less sunken side of the building, until the holes are drilled into the bottom surface of the sand and gravel layer 4 or the top surface of the bedrock layer 5;

[0036] S2. When reaching the top of the bedrock layer 5, stop drilling temporarily, inject water into the borehole 3, and use high-pressure wind to flush. In this way, the silty silt at the bottom of the sand and gravel layer 4 is blown up by the high-pressure wind, and the less submerged side 11 of the building begins to settle, and the building 9 begins to tilt back. Figure 1 As shown;

[0037] S3, when the building 9 tilts back to a point close to the tilt correction target, stop the water injection and air blowing operation, and continue to drill downwards using the drilling rig until the hole enters the bedrock layer 5 by 12 m, and then stop drilling;

[0038] S4, insert anchor cable 2 into borehole 3 and start grouting, control the liquid level of cement slurry 6 not to exceed the top surface of bedrock layer 5, if attached Figure 2 As shown;

[0039] S5. When the anchor cable 2 reaches the age of grouting, the jack 10 starts to gradually apply force to the anchor cable 2. The force applied by the anchor cable 2 can accelerate the settlement of the building foundation 1. Since the anchor cable force can be fully controlled by the electric oil pump and the jack, there is no problem of excessive tilt correction. Figure 2 As shown;

[0040] S6. If the anchor cable 2 is loaded to the design load, but the building 9 still cannot tilt back to the target value, the drilling hole 3 can be used to continue to inject water and blow air into the sand and gravel layer 4 to disturb it. In this way, water injection and blowing and anchor cable pressurization are performed alternately until the tilt correction target is reached;

[0041] S7, after the tilt correction is completed, the borehole 3 in the free section 32 is pressure grouting, and the cement slurry fills the gaps in the sand and gravel layer 4 after flushing. Finally, the anchor cable 2 is tensioned and locked by the working anchor 7, which can play the role of anti-re-tilt reinforcement. Figure 3 shown.

[0042] This construction method does not require large-scale drilling of holes on the foundation, nor does it require the excavation of shafts, so as to minimize damage to the foundation and disturbance to the ground. Only a row of holes is drilled every 3.0m or so on the overhanging part of the foundation on the less-sunken side. The holes are drilled twice. The first hole is drilled to the bottom of the gravel layer, and the hole is also used as a correction hole for flushing and blowing air. The second hole is drilled to 12m below the bedrock layer, and the anchor cable is inserted and grouting is performed to the bottom of the gravel layer to provide a reaction force for the anchor cable anchoring. The holes above the gravel layer are not grouted for the time being, and can still be reserved for flushing and blowing air correction until the correction target is achieved. Try to make the holes have multiple uses. In the process of correction, the anchor cable is used as an external force and control tool. After the correction is completed, it is locked in position and can become an important measure for anti-re-tilting reinforcement, and can also achieve multiple uses of one object.

[0043] The present invention is not limited to the above-mentioned embodiments. No matter any changes are made in the shape or material composition, any structural design provided by the present invention is a variation of the present invention and should be considered to be within the protection scope of the present invention.

Claims

1. A construction method for a building tilt correction and sinking acceleration device, characterized in that: A building tilt correction and sinking promotion device comprises a building foundation (1) and an anchor cable (2), wherein a borehole (3) is drilled on the building foundation (1), and the borehole (3) sequentially passes through a gravel layer (4) and a bedrock layer (5) in the foundation at the bottom of the building foundation (1); one end of the anchor cable (2) is inserted into the borehole (3) and fixed with cement slurry (6), and the other end is located outside the building foundation (1) and tensioned and locked with a working anchor (7); the borehole (3) is divided into an anchoring section (31) and a free section (32), wherein the anchoring section (31) is located in the bedrock layer (5) of the foundation, and the free section (32) is located in the gravel layer (4) of the foundation; and a construction method of the building tilt correction and sinking promotion device comprises the following steps: S1. Drill a row of vertical holes (3) at the overhanging part of the foundation on the less submerged side (11) of the building (9) using a drilling rig until the holes are drilled into the top surface of the bedrock layer (5); S2. When reaching the top of the bedrock layer (5), the drilling is temporarily stopped, water is injected into the borehole (3), and high-pressure air is used for flushing. In this way, the silty silt at the bottom of the sand and gravel layer (4) is blown up by the high-pressure air, and the less subsiding side of the building (11) begins to settle, and the building (9) begins to tilt back; S3. When the building (9) tilts back to a point close to the tilt correction target, the water injection and air blowing operation is stopped, and the drilling rig is continued to drill downward until the hole enters the bedrock layer (5) by 12 m; S4, inserting the anchor cable (2) into the borehole (3) and starting grouting, controlling the liquid level of the cement slurry (6) not to exceed the top surface of the bedrock layer (5); S5. When the anchor cable (2) reaches the age of grouting, the anchor cable (2) is gradually tensioned by means of the jack (10), and the anchor cable (2) is used to apply force to accelerate the settlement of the building foundation (1); S6. If the anchor cable (2) is loaded to the design load and still cannot make the building (9) tilt back to the target value, the drilling hole (3) is used to continue to inject water and blow air into the gravel layer (4) to disturb it, and the injection of water and blowing air and the pressurization of the anchor cable (2) are performed alternately until the tilt correction target is achieved; S7. After the tilt correction is completed, the borehole (3) in the free section (32) is pressure-grouted, and the cement slurry fills the gaps in the sand and gravel layer (4) after flushing. Finally, the anchor cable (2) is tensioned and locked by the working anchor (7), thereby achieving the effect of preventing re-tilting and strengthening.

2. The construction method of the building tilt correction and sinking acceleration device according to claim 1 is characterized in that: The building foundation (1) is divided into a less-sinking side (11) and a more-sinking side (12), and a pit (8) is dug on the ground of the less-sinking side (11); the drill hole (3) is located on the less-sinking side (11) of the building foundation (1).

3. The construction method of the building tilt correction and sinking acceleration device according to claim 2 is characterized in that: A plurality of equally arranged boreholes (3) are drilled on the building foundation (1) on the less-sunken side (11), and the distance between two adjacent boreholes (3) is 3 m.

4. The construction method of the building tilt correction and sinking acceleration device according to claim 1 is characterized in that: The diameter of the drill hole (3) is 140 to 160 mm.

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