Construction method of integral sinking underground permanent wall body capable of taking soil in wall

Abstract

The invention relates to a method for constructing an integral sinking underground permanent wall body by taking soil in a wall. The method comprises the following steps: prefabricating an underground permanent wall body with an open hole in the middle on the ground; the underground permanent wall body sinks, and soil taking equipment is synchronously used for taking soil in the holes of the underground permanent wall body till the underground permanent wall body sinks to the designed elevation; and filling core grouting concrete into the holes of the underground permanent wall body. The prefabricated underground permanent wall body is matched with the soil taking equipment to achieve sinking while taking soil, disturbance to surrounding soil is small, safety is high, the underground permanent wall body is used for replacing a supporting pile or wall and an underground permanent structural wall which is cast in situ after excavation, holes are formed in the middle in advance, and materials and engineering cost are greatly saved; overall prefabrication is conducted on the ground, and the stress performance and the waterproof performance are good; a foundation pit does not need to be excavated before construction, soil in the wall body can be excavated under the condition of no rainfall after the wall body sinks to the designed elevation, underwater bottom sealing is carried out after the wall body is excavated to the designed elevation, and the influence on the surrounding environment is small.

Description

Technical Field

[0001] The invention relates to the technical field of underground engineering construction, and in particular to a method for constructing an integrally sunken underground permanent wall by taking soil from inside the wall. Background Art

[0002] When constructing the permanent wall of an underground project, a common method is to first use temporary support piles or walls to form a support structure. When there is groundwater, a precipitation well is set up at the same time. After the temporary support structure reaches the strength, the earth in the foundation pit is excavated. When there is groundwater, precipitation is required. The bottom plate is constructed after excavation to the bottom plate elevation. After the bottom plate is constructed, the reinforced concrete wall is constructed. The construction period is long. The foundation pit support piles or walls are generally only used as temporary support structures, which are poor in economy. In addition, precipitation is required when excavating the soil in the foundation pit when there is groundwater. Precipitation will cause ground settlement around the construction site, affecting the safety of surrounding buildings (structures) and underground pipelines. Some underground projects are constructed by reverse construction. The foundation pit retaining structure uses reinforced concrete underground continuous wall. The length of the trough unit section is limited, so there are many vertical joints, and the quality of underwater concrete pouring is difficult to guarantee. In addition, the horizontal steel bars cannot be continuous, and the steel bars between the trough sections must be disconnected. The horizontal force is poor, which generally cannot be directly used for permanent structures. Precipitation must be used during construction, affecting the safety of the surrounding environment. Some underground structures use reinforced concrete caisson technology. During the sinking process of the caisson, the middle soil needs to be excavated to the blade foot. During the excavation process, the surrounding soil tends to flow into the middle, causing the soil around the caisson to sink and the road surface to crack, affecting the safety of the surrounding environment. When the caisson is made in sections, the excavation of the soil between the walls increases the difficulty of erecting and supporting the upper scaffolding. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an integral sunken underground permanent wall construction method for taking soil from inside the wall in view of the deficiencies in the above-mentioned prior art, so as to solve the shortcomings of the conventional open excavation in the current market, such as first constructing support and then excavating the bottom plate side wall, resulting in a long construction period and poor economy, or the shortcomings of the reinforced concrete underground continuous wall with horizontal steel bars that are not continuous and have many joints that are prone to water leakage.

[0004] The technical solution of the present invention to solve the above technical problems is as follows: A method for constructing an integrally sunken underground permanent wall by taking soil from inside the wall, comprising the following steps:

[0005] An underground permanent wall with openings in the middle of the ground prefabrication;

[0006] The underground permanent wall is sunk, and soil is taken from the opening of the underground permanent wall by using soil taking equipment simultaneously, until the underground permanent wall is sunk to the designed elevation;

[0007] The openings of the underground permanent wall are filled with core concrete.

[0008] The beneficial effects of the present invention are as follows: the method for constructing an integrally sunken underground permanent wall for taking soil inside the wall of the present invention realizes taking soil while sinking by cooperating with a prefabricated underground permanent wall and taking soil equipment, which has little disturbance to the surrounding soil and high safety. The underground permanent wall is used to replace the supporting piles or walls and the underground permanent structural wall that is cast again after excavation. During the construction process, there is no need to first drive supporting piles or walls for support and excavate the foundation pit before constructing the underground structural wall, and a hole is opened in the middle in advance, which greatly saves materials and engineering costs; the whole is prefabricated on the ground, and the stress-bearing performance and waterproof performance are good; there is no need to excavate the foundation pit before construction, and no precipitation is required. After sinking to the designed elevation, the soil inside the wall can be excavated without precipitation. During excavation, the middle part is excavated first, and then the surrounding soil is excavated symmetrically. After excavation to the designed elevation, the bottom is sealed underwater, which has little impact on the surrounding environment.

[0009] On the basis of the above technical solution, the present invention can also be improved as follows:

[0010] Further: the inner and outer sides of the opening of the underground permanent wall are respectively configured with continuous horizontal steel bars and / or vertical steel bars.

[0011] The beneficial effect of the above further scheme is that the structural strength of the entire wall can be increased by pre-setting horizontal steel bars and / or vertical steel bars, the force requirements can be met, the safety of construction can be ensured, and the joints of the underground permanent wall can be reduced during segmented prefabrication.

[0012] Further: when the underground permanent wall is prefabricated on the ground, grouting pipes for injecting thixotropic slurry during the sinking process are buried around and at intervals along the inner and outer sides of the underground permanent wall.

[0013] The beneficial effects of the above further scheme are: when sinking is difficult, thixotropic mud is injected through the grouting pipe, and thixotropic mud is injected into the grouting pipe on the outer side of the underground permanent wall, which can assist the wall in sinking during the wall sinking process, reduce the friction between the underground permanent wall and the surrounding soil, and accelerate the sinking of the underground permanent wall; after the wall sinks to the designed elevation, cement slurry can be injected through the grouting pipe, which can reinforce the soil around the outer wall, increase the friction between the underground permanent wall and the surrounding soil, and prevent the underground permanent wall from continuing to sink; cement slurry is injected into the grouting pipes on the inner side of the underground permanent wall and on both sides of the inner wall, and the leaking places between the bottom concrete and the underground permanent wall can be grout-sealed to ensure the construction conditions of the underground permanent structure floor.

[0014] Further: before prefabricating the underground permanent wall on the ground, a guide wall is arranged on the ground at the prefabrication position of the underground permanent wall.

[0015] The beneficial effect of the above further solution is that by providing the guide wall, the underground permanent wall can be easily sunk, thereby ensuring the accuracy and safety of the construction.

[0016] Further: when the underground permanent wall is prefabricated on the ground, a groove is provided on the underground permanent wall at a location corresponding to the installation of the horizontal member, and reserved steel bars for connection with the bottom plate or the top plate are provided on the outer side of the underground permanent wall.

[0017] The beneficial effects of the above further solution are: by providing the groove, the installation of the horizontal component can be facilitated, and by providing the reserved steel bars, the connection with the floor or the top plate can be facilitated, thereby improving the structural stability of the entire wall.

[0018] Further: before filling the opening of the underground permanent wall with core concrete, the following steps are also included:

[0019] Underwater concrete is poured in the opening of the underground permanent wall below the groove, and bottom sealing is performed.

[0020] The beneficial effect of the above further scheme is that by pouring underwater concrete in the opening of the underground permanent wall below the groove and performing bottom sealing treatment, the cushion layer can be constructed conveniently and the reinforced concrete bottom plate of the underground structure can be poured in time.

[0021] Further: the underground permanent wall is prefabricated and sunk in sections until the underground permanent wall sinks to the designed elevation.

[0022] The beneficial effect of the above further scheme is that by prefabricating and sinking the underground permanent wall in sections, on the one hand, the construction difficulty is reduced, the construction convenience is improved, and the construction cost is reduced; on the other hand, it is conducive to improving the construction accuracy and making the construction more flexible.

[0023] Further: when the underground permanent wall is sunk and soil is taken from the opening of the underground permanent wall by using soil taking equipment simultaneously, soil of a set depth is left in the opening.

[0024] The beneficial effect of the above further scheme is that by leaving a set depth of soil in the opening, the underground permanent wall can be prevented from sinking too quickly, thereby ensuring construction safety and facilitating the control of construction accuracy.

[0025] Further: when filling the opening of the underground permanent wall with core concrete, the following steps are specifically included:

[0026] Filling the bottom of the opening of the underground permanent wall with a first height of shrinkage compensating concrete, wherein the first height is not less than 1.2 m or 1.5 times the diameter or side length of the opening;

[0027] Filling the middle of the opening of the underground permanent wall with ordinary soil;

[0028] The top of the opening of the underground permanent wall is first filled with shrinkage compensating concrete of a second height, and the second height is not less than 1.2m.

[0029] The beneficial effect of the above further solution is that by filling shrinkage compensating concrete and ordinary soil, the anti-floating performance of the entire underground permanent wall can be conveniently improved, which is also beneficial to the stability of the underground permanent wall in the ground soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a cross-sectional schematic diagram of an integrally sunken underground permanent wall for taking soil from the wall of the present invention;

[0031] Figure 2 It is a schematic plan view of an integrally sunken underground permanent wall for taking soil from inside the wall of the present invention.

[0032] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0033] 1. Permanent underground wall, 2. Opening, 3. Groove, 4. Reserved steel bars, 5. Guide wall, 6. Concrete core at the bottom of the hole, 7. Grouting pipe, 8. Earth-taking equipment. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0035] like Figure 1 and Figure 2 As shown, a method for constructing an integrally sunken underground permanent wall by taking soil from inside the wall comprises the following steps:

[0036] An underground permanent wall 1 with an opening 2 in the middle prefabricated on the ground;

[0037] Without excavating the foundation pit, the underground permanent wall 1 is sunk, and soil is taken from the opening 2 of the underground permanent wall 1 by using soil taking equipment 8, until the underground permanent wall 1 is sunk to the designed elevation;

[0038] The opening 2 of the underground permanent wall 1 is filled with core concrete 6 .

[0039] The method for constructing an integrally sunken underground permanent wall for taking soil inside the wall of the present invention realizes taking soil while sinking by means of a prefabricated underground permanent wall 1 in cooperation with soil taking equipment 8, which causes little disturbance to the surrounding soil and has high safety. The underground permanent wall is used to replace the supporting piles or walls and the underground permanent structural wall that is cast again after excavation. During the construction process, there is no need to first drive supporting piles or walls for support and excavate the foundation pit before constructing the underground structural wall, and a hole is opened in the middle in advance, which greatly saves materials and engineering costs. The overall prefabrication is carried out on the ground, and the stress-bearing performance and waterproof performance are good. Before construction, there is no need to excavate the foundation pit or to precipitate water. After sinking to the designed elevation, the soil inside the wall can be excavated without precipitation. During excavation, the middle part is excavated first, and then the surrounding soil is excavated symmetrically. After excavation to the designed elevation, the bottom is sealed underwater, which has little impact on the surrounding environment.

[0040] It should be noted that in the embodiment of the present invention, the thickness of the underground permanent wall 1 can adopt a single cross-section or a variable cross-section as needed, the middle opening can adopt various shapes such as circular, elliptical, rectangular, etc., and the opening size and opening ratio are determined according to the force requirements.

[0041] In one or more embodiments of the present invention, continuous horizontal steel bars and / or vertical steel bars are respectively arranged on the inner and outer sides of the opening 2 of the underground permanent wall 1. By pre-arranging horizontal steel bars and / or vertical steel bars, the structural strength of the entire wall can be increased, the force requirements can be met, the safety of construction can be ensured, and the joints of the underground permanent wall 1 can be reduced during segment prefabrication.

[0042] Here, the inner and outer sides of the middle opening of the underground permanent wall 1 are normally reinforced with horizontal and vertical steel bars according to the force requirements, and the steel bar protection layer needs to meet the requirements of the current specifications.

[0043] Optionally, in one or more embodiments of the present invention, when the underground permanent wall 1 is prefabricated on the ground, grouting pipes 7 for injecting thixotropic mud during the sinking process of the wall are buried at intervals along the inner and outer sides of the underground permanent wall 1. When sinking is difficult, injecting thixotropic mud through the grouting pipes 7 and injecting thixotropic mud through the outer grouting pipes of the underground permanent wall 1 can assist the wall in sinking, reduce the friction between the underground permanent wall 1 and the surrounding soil, and accelerate the sinking of the underground permanent wall 1; after the wall sinks to the designed elevation, cement slurry can be injected through the grouting pipes, which can play a role in reinforcing the soil around the outer wall, increase the friction between the underground permanent wall and the surrounding soil, and prevent the underground permanent wall from continuing to sink; injecting cement slurry through the grouting pipes 7 on the inner side of the underground permanent wall 1 and on both sides of the inner wall can grout and seal the leaking area between the bottom concrete and the underground permanent wall 1 to ensure the construction conditions of the underground permanent structure bottom plate.

[0044] When the soil is good and difficult to sink, a grouting pipe 7 with a one-way valve for injecting thixotropic mud can be buried inside and outside the underground permanent wall 1. Thixotropic mud can be injected to reduce resistance during the sinking process. Before pouring concrete for the underground permanent wall 1, the grouting pipe 7 needs to be pre-buried, and the vertical joints of the grouting pipe 7 can be connected by welding or bolts.

[0045] In one or more embodiments of the present invention, before the underground permanent wall 1 is prefabricated on the ground, a guide wall 5 is provided on the ground at the prefabrication position of the underground permanent wall 1. By providing the guide wall 5, the underground permanent wall 1 can be easily sunk, ensuring the accuracy and safety of the construction.

[0046] In one or more embodiments of the present invention, when the underground permanent wall 1 is prefabricated on the ground, a groove 3 is provided on the underground permanent wall 1 at a location corresponding to the installation of the horizontal member, and a reserved steel bar 4 for connecting with the bottom plate or the top plate is provided on the outside of the underground permanent wall 1. The groove 3 can facilitate the installation of the horizontal member, and the reserved steel bar 4 can facilitate the connection with the floor or the top plate, thereby improving the structural stability of the entire wall.

[0047] Optionally, in one or more embodiments of the present invention, before filling the opening 2 of the underground permanent wall 1 with the core-casting concrete 6, the following steps are also included:

[0048] Underwater concrete is poured in the opening 2 of the underground permanent wall 1 below the groove 3 and a bottom sealing treatment is performed.

[0049] By pouring underwater concrete in the opening 2 of the underground permanent wall 1 below the groove 3 and performing bottom sealing, the cushion layer can be constructed conveniently and the reinforced concrete bottom plate of the underground structure can be poured in time.

[0050] In practice, after the underground permanent wall 1 sinks to the design elevation, the soil inside the underground permanent wall 1 can be excavated without precipitation. During excavation, the middle part is excavated first, and then the surrounding soil is excavated symmetrically. After excavation to the design elevation, the bottom is sealed underwater, which has little impact on the surrounding environment. When there is no groundwater, the bottom can be dry sealed, and the reinforced concrete bottom plate of the underground structure can be poured in time after the cushion layer is constructed.

[0051] In one or more embodiments of the present invention, the underground permanent wall 1 is prefabricated and sunk in sections until the underground permanent wall 1 is sunk to the designed elevation. By prefabricating and sinking the underground permanent wall 1 in sections, on the one hand, the construction difficulty is reduced, the convenience of construction is improved, and the construction cost is reduced; on the other hand, it is conducive to improving the construction accuracy and making the construction more flexible.

[0052] In practice, after the whole is prefabricated on site to a certain height, various soil-taking equipment 8 is used to take soil from the middle opening 2 in the wall to reduce the resistance of the wall sinking, so that the top of the wall section of the segmented underground permanent wall 1 sinks to the ground. During the sinking process, the soil between the underground permanent wall 1 does not need to be excavated, which is convenient for the erection and formwork of the scaffolding during the segmented casting, reducing the construction difficulty, and then the next segmented underground permanent wall 1 is cast vertically, and soil is taken from the opening 2 in the middle of the underground permanent wall 1 to sink until the designed elevation. The soil-taking equipment 8 can adopt various soil-taking equipment, such as spiral drill, rotary drilling drill, grab bucket, mud suction machine, etc., and the excavation equipment is selected according to the groundwater and soil layer conditions. When there is no groundwater, rotary drilling drill, grab bucket, etc. can be used, and when there is groundwater, mud suction machine, etc. can be used.

[0053] In an embodiment of the present invention, the soil-taking equipment 8 can extend below the bottom of the underground permanent wall 1. When the soil quality is good, a bottom drill bit can be used in the hole to expand the bottom and drill to take soil. The bottom protection diameter is not larger than the wall width to reduce the end resistance of the underground permanent wall 1 when it sinks, so that the underground permanent wall 1 can sink smoothly.

[0054] In one or more embodiments of the present invention, when the underground permanent wall 1 is sunk and soil is taken from the opening 2 of the underground permanent wall 1 using soil taking equipment, a set depth of soil is left in the opening 2. By leaving a set depth of soil in the opening 2, the underground permanent wall 1 can be prevented from sinking too fast, thereby ensuring construction safety and facilitating control of construction accuracy.

[0055] After sinking into place, the middle opening 2 can be filled with core concrete 6 according to the need for anti-floating.

[0056] In one or more embodiments of the present invention, when filling the core concrete 6 into the opening 2 of the underground permanent wall 1, the following steps are specifically included:

[0057] The bottom of the opening 2 of the underground permanent wall 1 is first filled with shrinkage compensating concrete of a first height, wherein the first height is not less than 1.2 m or 1.5 times the hole diameter or side length of the opening 2;

[0058] Filling the middle of the opening 2 of the underground permanent wall 1 with ordinary soil;

[0059] The top of the opening 2 of the underground permanent wall 1 is first filled with shrinkage compensating concrete of a second height, and the second height is not less than 1.2 m.

[0060] By filling shrinkage compensating concrete and ordinary soil, the anti-floating performance of the entire underground permanent wall 1 can be easily improved, which is also beneficial to the stability of the underground permanent wall 1 in the ground soil.

[0061] It should be pointed out that when the inner wall of the underground permanent wall 1 arranged according to functional needs is relatively small, the span of the outermost wall is relatively large, the force is large, and the required outer wall thickness is large. It can be combined with the force requirements of the permanent structure, and reinforced concrete beams can be used in the lower part, and brick or steel casing structure can be used in the upper part. Reinforced concrete columns are set at the permanent structural columns on the beams, and reinforced concrete beams are set at the corresponding elevations of the floor to form a three-dimensional support, which is convenient for the structure to bear force and more economical. Holes are required in the middle of the upper and lower parts to facilitate soil excavation, and the arrangement of the beams is arranged in combination with the force requirements of the structure.

[0062] It should be noted that, in one or more embodiments of the present invention, after the underground permanent wall 1 is cast as a whole on site to a certain height, an earth-taking device 8 is arranged on the ground, and the earth-taking device 8 is used to take soil at the middle opening 2 in the wall to reduce the resistance of the wall to sink and make the underground permanent wall 1 sink. When taking soil, soil is taken evenly on all sides, and the top surface elevation and inclination of the underground permanent wall 1 are measured at any time. After the top of the segment sinks to the ground, scaffolding and formwork are set up on the ground, and the next section of the underground permanent wall 1 is cast vertically in segments, and soil is taken and sunk in the middle opening 2 of the underground permanent wall 1 until the underground permanent wall 1 sinks to the designed elevation.

[0063] The method for constructing an integrally sunken underground permanent wall by taking soil from inside the wall of the present invention can realize the one-time construction of the underground permanent wall, does not require a temporary foundation pit support structure, has good integrity, does not require horizontal reinforcement of the wall to be cut off, can be continuously reinforced, and has good stress-bearing performance and waterproof performance.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for constructing an integrally sunken underground permanent wall by taking soil from the wall, characterized in that: The steps include: An underground permanent wall (1) prefabricated on the ground and having an opening (2) in the middle; The underground permanent wall (1) is sunk, and soil is simultaneously taken from the opening (2) of the underground permanent wall (1) using soil taking equipment (8) until the underground permanent wall (1) is sunk to the designed elevation; The opening (2) of the underground permanent wall (1) is filled with core concrete (6).

2. The method for constructing an integrally sunken underground permanent wall for taking soil from inside the wall according to claim 1, characterized in that: The inner and outer sides of the opening (2) of the underground permanent wall (1) are respectively provided with continuous horizontal steel bars and / or vertical steel bars.

3. The method for constructing an integrally sunken underground permanent wall for taking soil from inside the wall according to claim 2, characterized in that: When the underground permanent wall (1) is prefabricated on the ground, grouting pipes (7) for injecting thixotropic slurry during the sinking process are buried at intervals around the inner and outer sides of the underground permanent wall (1).

4. The method for constructing an integrally sunken underground permanent wall for taking soil from inside the wall according to claim 1, characterized in that: Before the underground permanent wall (1) is prefabricated on the ground, a guide wall (5) is arranged on the ground at the prefabrication position of the underground permanent wall (1).

5. The method for constructing an integrally sunken underground permanent wall for taking soil from inside the wall according to claim 4, characterized in that: When the underground permanent wall (1) is prefabricated on the ground, a groove (3) is provided on the underground permanent wall (1) at a location corresponding to the installation of the horizontal component, and a reserved steel bar (4) for connection with the bottom plate or the top plate is provided on the outer side of the underground permanent wall (1).

6. The method for constructing an integrally sunken underground permanent wall for taking soil from inside the wall according to claim 3, characterized in that: Before filling the opening (2) of the underground permanent wall (1) with core-casting concrete (6), the following steps are also included: Underwater concrete is poured in the opening (2) of the underground permanent wall (1) below the groove (3), and a bottom sealing process is performed.

7. The method for constructing an integrally sunken underground permanent wall for taking soil from inside the wall according to claim 1, characterized in that: The underground permanent wall (1) is prefabricated and sunk in sections until the underground permanent wall (1) sinks to the designed elevation.

8. The method for constructing an integrally sunken underground permanent wall for taking soil from inside the wall according to claim 1, characterized in that: When the underground permanent wall (1) is sunk and soil is taken from the opening (2) of the underground permanent wall (1) using soil taking equipment, soil of a set depth is left in the opening (2).

9. The method for constructing an integrally sunken underground permanent wall for taking soil from inside the wall according to any one of claims 1 to 8, characterized in that: When filling the opening (2) of the underground permanent wall (1) with ordinary soil (6), the following steps are specifically included: The bottom of the opening (2) of the underground permanent wall (1) is first filled with shrinkage compensating concrete of a first height, wherein the first height is not less than 1.2 m or 1.5 times the hole diameter or side length of the opening (2); Filling the middle of the opening (2) of the underground permanent wall (1) with ordinary soil (6); The top of the opening (2) of the underground permanent wall (1) is first filled with shrinkage compensating concrete of a second height, wherein the second height is not less than 1.2 m.

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