Non-dismantling reinforcing method for basement transformation outer wall

Abstract

The dismantling-free reinforcing method comprises the steps that drilling is carried out on the inner side of the basement outer wall to form a plurality of obliquely-downward hole channels, the hole channels extend into a soil body, the position of each hole channel corresponds to the position of each floor, each hole channel comprises a plurality of drill holes, and the drill holes are formed in the circumferential direction of the basement outer wall; a pre-stressed anchor cable is provided, the pre-stressed anchor cable is placed in the drill hole, and the anchoring end of the pre-stressed anchor cable is sleeved with a wrapping bag; cement paste is pressed into the wrapping bag, and then the cement paste is pressed into the drill hole to wrap the free end of the pre-stressed anchor cable and the wrapping bag; the steel strand of the pre-stressed anchor cable is tensioned, so that the integrity and internal resistance of the surrounding rock are improved, the strength is enhanced, and the stable strength of the surrounding rock is improved; original floor slabs on the basement outer wall are dismantled, and newly-built floor slabs are constructed; and dismantling the pre-stressed anchor cables layer by layer from bottom to top. The problems that in the basement transformation process, the original outer wall dismantling and reconstruction cost is high, and the construction period is long are solved.

Description

Technical Field

[0001] The invention relates to the technical field of building construction, and in particular to a method for reinforcing an outer wall of a basement without demolition. Background Art

[0002] In recent years, the number of demolition and reconstruction projects has continued to increase. Due to the difference between the structural design of the new project and the original structure, the original structure needs to be demolished. When the basement beams and slabs are demolished, the basement exterior wall will lose its supporting force, and the external soil pressure will exert force on the basement exterior wall, which may cause damage to the exterior wall and cause the risk of collapse. In order to ensure the safety of the foundation pit during the demolition process, it is necessary to reinforce the original support. The traditional method is to use new ground-connected walls, retaining piles and other forms to increase the retaining system before demolition. Traditional ground-connected walls and retaining piles are costly, have a long construction period, and are more troublesome to construct. If the original exterior wall structure is relatively well preserved and the original exterior wall is to be used as the exterior wall of the new structure, the new ground-connected walls, retaining piles and other systems will cause great damage to the original exterior wall structure, and the protection cost is high. Summary of the invention

[0003] In order to overcome the defects of the prior art, a method for reinforcing the exterior wall of a basement renovation without demolition is provided to solve the problems of high cost and long construction period for demolition and reconstruction of the original exterior wall during the basement renovation process.

[0004] In order to achieve the above purpose, a method for strengthening the exterior wall of a basement without demolition is provided, comprising:

[0005] Drilling a plurality of channels obliquely downward from the inner side of the basement outer wall toward the soil outside the basement outer wall, the channels extending into the soil, the position of each channel corresponding to the position of each floor slab, each channel including a plurality of drill holes, and the plurality of drill holes being arranged along the circumferential direction of the basement outer wall;

[0006] Providing a prestressed anchor cable, placing the prestressed anchor cable in the drill hole, wherein the prestressed anchor cable has a free end and an anchor end opposite to each other, and the anchor end is sleeved with a wrapping bag;

[0007] Pressing cement slurry into the wrapping bag, and then pressing cement slurry into the drilled hole to cover the free end and the wrapping bag;

[0008] The steel strands of the prestressed anchor cables are tensioned, so that the surrounding rocks are elastically compressed by the prestressed anchor cables, thereby improving the integrity and inherent resistance of the surrounding rocks, increasing the strength, and enhancing the stability of the surrounding rocks;

[0009] Demolishing the original floor slab on the outer wall of the basement and constructing a new floor slab;

[0010] Remove multiple prestressed anchor cables layer by layer from bottom to top.

[0011] Furthermore, a tail pipe is inserted into the drilled hole on the outer wall of the basement, and the tail pipe is sleeved on the outside of the free end. The anchor head of the prestressed anchor cable is supported on the end surface of the tail pipe facing away from the soil. A supporting plate is formed on the outer side of the tail pipe, and the supporting plate abuts against the inner side of the outer wall of the basement.

[0012] Furthermore, the support plate is arranged in a circle along the circumferential direction of the tail pipe.

[0013] The beneficial effect of the present invention lies in that the method for reinforcing the exterior wall of a basement renovation without demolition of the present invention adopts a removable wrapped prestressed anchor cable, and by applying prestress, the anchor cable is passed through the exterior wall of the basement and anchored into the soil outside the foundation pit, so that the stress of the original exterior wall of the basement is reinforced and improved, and the risk of exterior wall collapse caused by the demolition of the basement floor is prevented. After the demolition of the underground floor slabs, the stability of the exterior wall of the basement and the entire foundation pit can still be maintained. After the construction of the new basement beam and slab structure is completed, the applied prestress is unloaded layer by layer, so that the exterior wall structure of the basement can be utilized to the maximum extent, the construction cost can be reduced, and the construction period can be shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0015] Figure 1 It is a structural schematic diagram of a method for reinforcing the exterior wall of a basement renovation without demolition according to an embodiment of the present invention.

[0016] Figure 2 for Figure 1 Cross-sectional view at AA in .

[0017] Figure 3 for Figure 1 Cross-sectional view at BB in .

[0018] Figure 4 for Figure 1 A local enlarged schematic diagram of point C in the figure. DETAILED DESCRIPTION

[0019] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0020] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0021] Reference Figures 1 to 4 As shown, the present invention provides a method for strengthening the exterior wall of a basement without demolition, comprising the following steps:

[0022] S1. Drill into the soil on the inner side of the basement outer wall 1 toward the outer side of the basement outer wall 1 to form multiple channels that are inclined downward, and the channels extend into the soil. The position of each channel corresponds to the position of each floor slab, and each channel includes multiple drill holes, and the multiple drill holes are arranged along the circumferential direction of the basement outer wall 1.

[0023] S2. Provide a prestressed anchor cable 2, and place the prestressed anchor cable 2 in the drill hole. The prestressed anchor cable 2 has a free end and an anchoring end opposite to each other, and the anchoring end is sleeved with a wrapping bag 21.

[0024] As a preferred embodiment, a tail pipe 3 is inserted into the drilled hole on the basement outer wall 1, and the tail pipe 3 is sleeved on the outside of the free end. The anchor head 23 of the prestressed anchor cable 2 is supported on the end face of the tail pipe 3 facing away from the soil. A support plate 31 is formed on the outside of the tail pipe 3, and the support plate 31 is against the inner side of the basement outer wall 1.

[0025] In this embodiment, the support plates 31 are arranged in a circle along the circumferential direction of the tail pipe 3 .

[0026] S3, press cement slurry into the wrapping bag 21, and then press cement slurry into the drilled hole to cover the free end and the wrapping bag 21.

[0027] S4. The steel strands 22 of the prestressed anchor cable 2 are tensioned, so that the surrounding rock is elastically compressed by the prestressed anchor cable 2, thereby improving the integrity and inherent resistance of the surrounding rock, increasing the strength, and enhancing the stable strength of the surrounding rock.

[0028] S5. Remove the original floor slab on the basement exterior wall 1 and construct a new floor slab.

[0029] S6. Remove multiple prestressed anchor cables 2 layer by layer from bottom to top.

[0030] The method for reinforcing the exterior wall of a basement renovation without demolition of the present invention adopts a detachable wrapped prestressed anchor cable. By applying prestress, the anchor cable passes through the exterior wall of the basement and is anchored into the soil outside the foundation pit, so that the stress of the original exterior wall of the basement is reinforced and improved, and the risk of exterior wall collapse caused by the demolition of the basement floor is prevented. After the demolition of the underground floor slabs, the stability of the exterior wall of the basement and the entire foundation pit can still be maintained. After the construction of the new basement beam and slab structure is completed, the applied prestress is unloaded layer by layer, so that the exterior wall structure of the basement can be utilized to the maximum extent, the construction cost can be reduced, and the construction period can be shortened.

[0031] During the construction of the prestressed anchor cable in this embodiment, the steel strand is buried inside the rock layer for prestressing, and the supporting stress of the basement outer wall is transferred to the deep stable rock layer. After the anchor cable is tensioned, the concentrated stress is transferred to the outer wall of the basement through the anchor cable. Under the action of prestress, the surrounding rock mass is compressed, but the surrounding rock forms a "bearing arch" under the elastic compression of the anchor cable, which improves the integrity and inherent resistance of the surrounding rock, increases its strength, and increases the stability strength of the surrounding rock. The anchor cable support makes the outer wall of the basement and the surrounding rock work together, which can make the surrounding rock play a greater bearing role, which is conducive to the stability of the surface structure, and the structure and the surrounding rock medium working together form a complex. The rock layer anchored by the structure can more effectively withstand the tension and shear force generated by the load, and the transmission depth of these forces is also much greater than that of the unanchored structure, thereby ensuring the stability of the entire deep foundation pit.

[0032] After structural verification, the construction of prestressed anchor cables is carried out in layers. After each anchor cable is constructed, the corresponding floor slab is removed. Conversely, for each new floor slab structure, the prestressed anchor cables of this layer are removed. Each layer of prestressed anchor cables and floor slabs can be used as supports for the original exterior walls. Only after the construction of the new supports is completed can the original supports be removed to ensure that the force of the original wall is consistent with the original calculation method.

[0033] The anchoring force of the wrapped prestressed anchor cable is provided by the pressure between the expanded part of the anchor section and the soil. The expanded part compresses the surrounding rock, increases the stability of the surrounding rock, makes the structure and the surrounding rock form a whole, and more effectively ensures the safety of the original exterior wall.

[0034] Cut off the protruding steel strand at the anchor head, remove the anchor and rotate the steel strand clockwise to separate the anchor wedge at the deepest part of the steel strand, and remove the steel strand by pulling.

[0035] To ensure the reinforcement effect, the present invention adopts a removable wrapped prestressed anchor cable, which includes a free end and an anchoring end. The diameter of the drill hole (anchor hole) is 105mm, which is processed by 4 12.7mm steel strands. The anchoring end of the prestressed anchor cable is covered with a polyester wrapping bag.

[0036] According to the construction drawings and design requirements, the anchor holes should be accurately measured and placed on the exterior wall. The hole position deviation should not exceed 50mm. The anchor holes should be marked, and the markings should be difficult to damage and eye-catching.

[0037] The position of the drilling rig should be strictly determined according to the hole position. The drilling inclination angle and direction should be consistent with the inclination direction of the hole diameter in the construction drawing. The allowable error of the inclination angle is within ±3°. The angle is controlled according to the compass of the drilling rig to ensure that the drill bit is aligned with the center of the hole.

[0038] In order to ensure the independent integrity of adjacent anchor holes during drilling, the method of drilling one by one is adopted. If the soil is soft, the noise is too loud, and there is a lot of dust, reasonable construction can be carried out by following up with casing, setting up sound insulation materials, and sprinkling water. The drilling depth is strictly in accordance with the design requirements, and the maximum error of the hole depth is 100mm. After drilling, the hole diameter is cleaned with an air compressor and the depth and angle of the anchor hole are measured and recorded.

[0039] Before placing the anchor cable, check whether the length, number of strands, specifications and diameter of the anchor cable are consistent with the drawings, and observe whether there is any bending or damage. After insertion, confirm whether the anchor cable has reached the depth indicated on the design drawings. To prevent wall instability caused by continuous drilling, the anchor cable should be inserted immediately after drilling.

[0040] The order of making cement slurry is to place water first, then add cement, and finally add expansion agent. The water-cement ratio is controlled at 45% to 50%. The cement slurry flow rate is determined by grouting test. 300ml cement slurry needs to be controlled within 4 to 5 seconds to complete the test. First, use a high-pressure pump to press the prepared cement slurry into the package bag of the anchor end through the grouting pipe 24. The grouting amount is controlled by the amount of mud falling in the cement slurry mixing barrel. After the cement slurry in the package is filled, grouting is performed on the outside of the anchor end package and the free end until the slurry overflows from the hole. The strength of the cement slurry is determined to meet the design requirements through the test block test.

[0041] Before tensioning, the tail pipe, support plate and anchor should be installed to ensure that the compressive strength of the slurry exceeds 21MPa. The lifting force of the anchor jack should be on the same axis as the anchor. To prevent prestress loss, the anchor should be kept for 10 minutes after applying the designed prestress value, and the elongation should be within 40mm, and then locked according to the design requirements. After tensioning is completed and locked, the exposed section of the anchor should be retained, and the exposed steel strands should be safely protected. The anchor head of the anchor should be checked regularly, and compensation tension should be carried out in time if the anchor is found to be loose.

[0042] When the strength of the structural floor beam reaches 100%, the anchor cable is removed layer by layer from bottom to top. First, the exposed steel strand of the anchor head is cut off and the anchor head is removed. Then, the steel strand is rotated clockwise to embed the wedge at the anchor end into the reserved tooth socket. The anchor cable is removed by pulling the steel strand.

[0043] The method for reinforcing the exterior wall of a basement renovation without demolition of the present invention uses removable wrapped prestressed anchor cables to reinforce the original exterior wall of the basement before the original underground structure is demolished, replacing retaining measures such as ground-connected walls and retaining piles. After the construction of the new beams and slabs of the basement is completed, the anchor cables are gradually removed for unloading.

[0044] The method for reinforcing the exterior wall of a basement renovation without demolition of the present invention adopts a removable wrapped prestressed anchor cable. By applying prestress, the stress of the original exterior wall of the basement is reinforced and improved. After the floor slabs of each underground layer are demolished, the stability of the exterior wall of the basement and the entire foundation pit can still be maintained. After the construction of the new structure is completed, the applied prestress is unloaded layer by layer to maximize the use of the exterior wall structure of the basement.

[0045] The basement renovation external wall non-dismantling reinforcement method of the present invention adopts a removable wrapped prestressed anchor cable, which can achieve the purpose of reinforcing the basement external wall and limiting its deformation. At the same time, the construction is convenient and fast, the recovery speed is fast, and the basement structure construction is not affected, which reduces the basement construction time to the greatest extent. The steel strands of the prestressed anchor cable are recycled to avoid underground pollution problems.

[0046] Compared with traditional reinforcement methods, the basement renovation exterior wall non-demolition reinforcement method of the present invention is particularly suitable for situations where the environment around the foundation pit is complex and the site is small.

[0047] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A method for strengthening the exterior wall of a basement without demolition, characterized in that: The following steps are involved: Drilling a plurality of channels obliquely downward from the inner side of the basement outer wall toward the soil outside the basement outer wall, the channels extending into the soil, the position of each channel corresponding to the position of each floor slab, each channel including a plurality of drill holes, and the plurality of drill holes being arranged along the circumferential direction of the basement outer wall; Providing a prestressed anchor cable, placing the prestressed anchor cable in the drill hole, wherein the prestressed anchor cable has a free end and an anchor end opposite to each other, and the anchor end is sleeved with a wrapping bag; Pressing cement slurry into the wrapping bag, and then pressing cement slurry into the drilled hole to cover the free end and the wrapping bag; The steel strands of the prestressed anchor cables are tensioned, so that the surrounding rocks are elastically compressed by the prestressed anchor cables, thereby improving the integrity and inherent resistance of the surrounding rocks, increasing the strength, and enhancing the stability of the surrounding rocks; Demolishing the original floor slab on the outer wall of the basement and constructing a new floor slab; Remove multiple prestressed anchor cables layer by layer from bottom to top.

2. The method for strengthening the exterior wall of a basement renovation without demolition according to claim 1 is characterized in that: A tail pipe is inserted into the drilled hole on the outer wall of the basement, and the tail pipe is sleeved on the outside of the free end. The anchor head of the prestressed anchor cable is supported on the end surface of the tail pipe facing away from the soil. A support plate is formed on the outer side of the tail pipe, and the support plate abuts against the inner side of the outer wall of the basement.

3. The method for strengthening the exterior wall of a basement renovation without demolition according to claim 2 is characterized in that: The support plate is arranged in a circle along the circumferential direction of the tail pipe.

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