A support device for excavating foundation pits on soft plateau soil

Abstract

The invention relates to the technical field of repair and reinforcement of foundation pit edges, and discloses a supporting device for excavating foundation pits on soft plateau foundations, comprising: a main support, which is pre-installed in a preset foundation trench before excavating a continuous supporting wall, and an anchoring mechanism is arranged at the center of the main support; the anchoring mechanism is used for drilling laterally in the direction of soil away from the center point of the foundation pit; wherein the anchoring mechanism specifically comprises an outer casing, a middle casing and an inner casing, the inner casing can slide inside the middle casing, and the middle casing can also slide inside the outer casing, forming a multi-stage nested combined structure with telescopic function; the supporting device of the invention can adapt to the complex geological conditions of soft plateau foundations through the multi-stage nested anchoring mechanism with telescopic function, and the telescopic structure design of the inner casing, the middle casing and the outer casing enables the anchoring mechanism to flexibly adjust the drilling depth and length according to the actual foundation conditions, effectively improving the stability and reliability of the support.

Description

Technical Field

[0001] The invention relates to the field of foundation pit edge repair and reinforcement, and more specifically, to a supporting device used for excavating a foundation pit on a soft plateau. Background Art

[0002] When excavating foundation pits in plateau areas, due to the complex geological conditions, the soil is mostly soft soil layers, such as frozen soil, backfill soil, silty soil, etc. These soils are characterized by high compressibility and low pull-out resistance. Traditional support technologies such as anchor support often find it difficult to provide sufficient anchoring force.

[0003] In addition, the plateau area also faces extreme climatic conditions, such as low temperature, strong wind, dryness and lack of oxygen, which place higher requirements on construction materials and processes. For example, low temperature will cause the concrete to set up for a longer time or even freeze, affecting the strength and stability of the support structure. At the same time, traditional support devices have many inconveniences during the construction process, such as the difficulty of inserting support rods into hard rock formations, or digging and melting in the frozen soil layer, resulting in unstable slopes.

[0004] For supporting structures such as underground continuous walls, although their integrity and stability are relatively good, under the soft foundation conditions of the plateau, due to the low soil bearing capacity, the supporting walls are easily tilted or collapsed by external loads, which will not only affect the smooth progress of foundation pit excavation, but also cause safety hazards to the surrounding environment. For this reason, we propose a supporting device for foundation pit excavation in soft foundations of the plateau. Summary of the invention

[0005] The present invention provides a supporting device for excavating a foundation pit on a plateau with a weak foundation, which solves the technical problem in the related art that under the condition of a plateau with a weak foundation, the supporting wall is easily tilted or collapsed due to the low bearing capacity of the soil, which is caused by the external load.

[0006] The present invention provides a support device for excavating a foundation pit on a plateau with soft foundation, comprising: a main support, which is pre-installed in a preset foundation trench before excavating a continuous retaining wall, and an anchoring mechanism is arranged at the center of the main support; the anchoring mechanism is used to drill into the soil in a direction away from the center of the foundation pit, and after drilling, concrete is poured to form an integrated structure with the subsequent retaining wall, thereby realizing lateral side pulling support for the continuous retaining wall;

[0007] The anchor pulling mechanism specifically includes an outer casing, a middle casing and an inner casing. The inner casing can slide inside the middle casing, and the middle casing can also slide inside the outer casing, forming a multi-level nested combined structure with telescopic function; extension pieces are respectively provided at the nested ends of the outer casing, the middle casing and the inner casing, and the outer walls of the three are equipped with expansion pieces;

[0008] The expansion piece drills into the soil as the outer casing, middle casing and inner casing rotate in the same direction, forming a threaded travel path, and then concrete is filled into these threaded grooves so that the concrete is tightly combined with the outer casing, middle casing and inner casing to form an integrated structure.

[0009] Furthermore, the main support includes a secondary support plate, which is parallel to the main support and is also pre-installed in a preset foundation trench before excavating the continuous support wall. The secondary support plate and the main support are respectively tightly attached to the inner wall of the preset foundation trench, and the main support is on the side away from the center point of the foundation pit.

[0010] Furthermore, two mutually parallel and symmetrical positioning grooves 2 are provided on the inner side of the main support, and two mutually parallel and symmetrical positioning grooves 1 are provided on the inner side of the secondary support plate. Positioning groove 1 and positioning groove 2 are aligned with each other, and a support is provided between positioning groove 1 and positioning groove 2.

[0011] Furthermore, a bearing body is arranged inside the main support, the outer casing passes through the center of the bearing body, and the outer ring wall of the bearing body is fixedly connected to the main support, and a top plate ring is fixedly arranged at one end of the outer casing close to the preset base groove, and a plurality of bolt holes are opened on the outer ring of the top plate ring, which are used to fix the outer casing and the bearing body with bolts after the outer casing, the middle casing and the inner casing are completely drilled into the soil.

[0012] Furthermore, a drilling rig connection port is fixedly provided at the center position of the top plate ring, and a cross-shaped connecting frame is fixedly provided between the drilling rig connection port and the top plate ring. The centers of the top plate ring, the drilling rig connection port and the bearing body coincide with each other. The drilling rig connection port is used for an external drilling rig to provide power for the outer casing, the middle casing and the inner casing to drill into the soil.

[0013] Furthermore, the expansion part includes soil entry hole one, expansion head one, soil entry hole two, expansion head two, soil entry hole three, and expansion head three. Soil entry hole one and expansion head one are a group and are arranged on the outer casing, soil entry hole two and expansion head two are a group and are arranged on the middle casing, and soil entry hole three and expansion head three are a group and are arranged on the inner casing.

[0014] Further, the expansion head 1 is arranged in the soil entry hole 1 through a torsion spring, the expansion head 2 is arranged in the soil entry hole 2 through a torsion spring, and the expansion head 3 is arranged in the soil entry hole 3 through a torsion spring.

[0015] Furthermore, a scraper head one is fixedly provided at one end of the outer casing away from the preset base groove, a scraper head two is fixedly provided outside the middle casing and at one end of the casing away from the preset base groove, a curved plate is fixedly provided inside the inner casing, a pressure plate is fixedly provided at one end of the curved plate, and a scraper head three is fixedly provided on the other side of the pressure plate, and scraper head three, scraper head two and scraper head one are aligned with each other and arranged in a straight line.

[0016] Furthermore, the extension piece includes a guide slider, a bulldozer head is fixedly provided on one side of the guide slider, and the bulldozer head is a triangle, and a pull tube belt is fixedly provided on one side of the bulldozer head for pulling the middle casing and the inner casing to extend with the depth of drilling into the soil.

[0017] Furthermore, the extension piece also includes a guide groove and a discharge hole, and both the middle casing and the inner casing are provided with a guide groove, and the guide groove matches the corresponding guide slider, and there are two groups of discharge holes, which are respectively opened in the walls of the middle casing and the inner casing.

[0018] The beneficial effects of the present invention are:

[0019] The support device of the present invention can adapt to the complex geological conditions of soft foundations on the plateau through the anchor-pull mechanism with multi-level nesting and telescopic function. The telescopic structural design of the inner casing, the middle casing and the outer casing enables the anchor-pull mechanism to flexibly adjust the drilling depth and length according to the actual foundation conditions, effectively improving the stability and reliability of the support. At the same time, the expansion member drills into the soil as the casing rotates to form a threaded travel route, which not only enhances the friction between the anchor-pull mechanism and the soil, but also can be closely combined with the casing by filling concrete to form an integrated structure, further improving the overall strength of the support, effectively solving the lateral deformation and collapse problems that are prone to occur during the excavation of foundation pits on soft foundations on the plateau, and ensuring the safety and stability of foundation pit construction.

[0020] The anchor-pull mechanism adopts a combination design of multi-stage telescopic casing and expansion parts, which has significant construction advantages. During the construction process, the telescopic function of the casing can be flexibly adjusted according to the foundation conditions, reducing the construction interruption and adjustment time caused by changes in geological conditions, and improving the construction efficiency. At the same time, the threaded travel route and concrete filling process formed by the expansion parts enable the anchor-pull mechanism to be closely combined with the supporting wall to form an integrated structure, which enhances the integrity and resistance to lateral deformation of the support, effectively reducing the construction risk and reducing the impact on the surrounding environment. It is especially suitable for foundation pit excavation projects under complex geological conditions in plateau areas, and has broad application prospects and significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention in the land;

[0022] Figure 2 It is a schematic diagram of the main support structure of the present invention;

[0023] Figure 3 It is a schematic diagram of the outer casing structure of the present invention;

[0024] Figure 4 It is a schematic diagram of the inner casing structure of the present invention;

[0025] Figure 5It is a schematic diagram of the top plate ring structure of the present invention;

[0026] Figure 6 It is a schematic diagram of the main structure of the anchor pulling mechanism of the present invention;

[0027] Figure 7 It is a schematic diagram of the internal structure of the anchor pulling mechanism of the present invention;

[0028] Figure 8 It is a schematic diagram of the inner structure of the main support of the present invention.

[0029] In the figure: 11, main support; 12, auxiliary support plate; 13, positioning groove one; 14, pillar; 15, positioning groove two; 2, anchor pulling mechanism; 21, outer casing; 22, top plate ring; 23, soil entry hole one; 24, expansion head one; 25, bolt hole; 26, scraper head one; 27, connecting frame; 28, drilling rig connection port; 31, middle casing; 32, soil entry hole two; 33, expansion head two; 34, scraper head two; 41, inner casing; 43, soil entry hole three; 44, expansion head three; 45, pressure plate; 46, scraper head three; 47, curved panel; 51, guide slider; 52, bulldozer head; 53, pull tube belt; 54, guide groove; 55, discharge hole; 6, bearing body. DETAILED DESCRIPTION

[0030] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0031] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a support device for excavating a foundation pit on a plateau with soft foundation includes: a main support 11, which is pre-installed in a preset foundation trench before excavating a continuous retaining wall, and an anchoring mechanism 2 is arranged at the center of the main support 11; the anchoring mechanism 2 is used to drill into the soil in a direction away from the center point of the foundation pit, and after drilling, concrete is poured to form an integrated structure with the subsequent retaining wall, thereby realizing lateral side pulling support for the continuous retaining wall;

[0032] Through the multi-level nested and telescopic anchoring mechanism 2, the lateral side pulling support of the continuous supporting wall is realized. This support method can effectively disperse the lateral pressure on the supporting wall and improve the overall stability of the supporting structure. At the same time, the setting of the expansion piece and the scraper head enables the anchoring mechanism 2 to form a deeper and wider thread groove in the process of drilling into the soil, further increasing the stability of the supporting structure;

[0033] The anchor pulling mechanism 2 specifically includes an outer casing 21, a middle casing 31 and an inner casing 41. The inner casing 41 can slide inside the middle casing 31, and the middle casing 31 can also slide inside the outer casing 21, forming a multi-level nested combined structure with telescopic function; extension pieces are respectively provided at the nested ends of the outer casing 21, the middle casing 31 and the inner casing 41, and the outer walls of the three are equipped with diameter expansion pieces;

[0034] The anchoring mechanism 2 is drilled into the soil away from the center of the foundation pit and poured with concrete, forming a lateral side support for the continuous retaining wall. This support method can effectively prevent the retaining wall from tilting toward the center of the foundation pit during the excavation process, and enhance the anti-overturning ability of the retaining wall. At the same time, because the anchoring mechanism 2 and the retaining wall form an integrated structure, the integrity of the retaining wall is stronger and more able to resist the effects of external loads;

[0035] The expansion piece drills into the soil as the outer casing 21, the middle casing 31 and the inner casing 41 rotate in the same direction, forming a threaded travel route, and then concrete is filled into these threaded grooves so that the concrete is tightly combined with the outer casing 21, the middle casing 31 and the inner casing 41 to form an integrated structure. When the outer casing 21, the middle casing 31 and the inner casing 41 are deeply embedded in the soil, when concrete is injected into the subsequent retaining wall, the concrete will also enter the outer casing 21, the middle casing 31 and the inner casing 41.

[0036] The main support 11 includes a secondary support plate 12, which is parallel to the main support 11 and is also pre-installed in a preset foundation trench before excavating the continuous support wall. The secondary support plate 12 and the main support 11 are respectively tightly attached to the inner wall of the preset foundation trench, and the main support 11 is on the side away from the center point of the foundation pit. Before excavating the continuous support wall trench, it is necessary to first excavate the preset foundation trench, and support the preset foundation trench by both the secondary support plate 12 and the main support 11.

[0037] Two mutually parallel and symmetrical positioning grooves 15 are provided on the inner side of the main support 11, and two mutually parallel and symmetrical positioning grooves 13 are provided on the inner side of the secondary support plate 12. The positioning groove 13 and the positioning groove 2 15 are aligned with each other, and a support column 14 is provided between the positioning groove 13 and the positioning groove 2 15, and the secondary support plate 12 and the main support 11 are supported by the support column 14.

[0038] A bearing body 6 is arranged inside the main support 11, an outer casing 21 passes through the center of the bearing body 6, and the outer ring wall of the bearing body 6 is fixedly connected to the main support 11, and a top plate ring 22 is fixedly arranged at one end of the outer casing 21 close to the preset base groove. A plurality of bolt holes 25 are opened on the outer ring of the top plate ring 22, which are used to fix the outer casing 21 and the bearing body 6 with bolts after the outer casing 21, the middle casing 31 and the inner casing 41 are completely drilled into the soil.

[0039] A drilling rig connection port 28 is fixedly provided at the center position of the top plate ring 22, and a cross-shaped connecting frame 27 is fixedly provided between the drilling rig connection port 28 and the top plate ring 22. The centers of the top plate ring 22, the drilling rig connection port 28 and the bearing body 6 coincide with each other. The drilling rig connection port 28 is used for an external drilling rig to provide power for the outer casing 21, the middle casing 31 and the inner casing 41 to drill into the soil. After the secondary support plate 12 and the main support 11 are installed, the external drilling rig and the drilling rig connection port 28 are used to drive the outer casing 21 to rotate through the drilling rig to drill into the soil horizontally.

[0040] like Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, the expansion part includes a soil entry hole 23, an expansion head 24, a soil entry hole 32, an expansion head 33, a soil entry hole 343, and an expansion head 34. The soil entry hole 23 and the expansion head 24 are a group arranged on the outer casing 21, the soil entry hole 32 and the expansion head 33 are a group arranged on the middle casing 31, and the soil entry hole 343 and the expansion head 34 are a group arranged on the inner casing 41.

[0041] The expanding head 24 is arranged in the soil entry hole 23 through a torsion spring, the expanding head 2 33 is arranged in the soil entry hole 2 32 through a torsion spring, and the expanding head 3 44 is arranged in the soil entry hole 3 43 through a torsion spring. As the outer casing 21 rotates, the expanding head 24 will always be pushed out under the elastic force of the torsion spring, and the soil will be scraped as it rotates. The outer casing 21 penetrates into the soil, and the travel path of the expanding head 24 is a threaded groove. When the outer casing 21 extends to the maximum value, as the expanding head 24 is rotated, the soil will gradually be scraped at the maximum position to form a deep groove with a diameter greater than the diameter of the outer casing 21. The expanding parts on the middle casing 31 and the inner casing 41 work the same as the expanding head 24 of the outer casing 21.

[0042] A scraper head 26 is fixedly provided at one end of the outer casing 21 away from the preset base groove, a scraper head 2 34 is fixedly provided at one end of the middle casing 31 and the outer casing 21 away from the preset base groove, a curved plate 47 is fixedly provided inside the inner casing 41, a pressure plate 45 is fixedly provided at one end of the curved plate 47, and a scraper head 3 46 is fixedly provided on the other side of the pressure plate 45, and the scraper head 3 46, the scraper head 2 34 and the scraper head 1 26 are aligned with each other and arranged in a straight line. When the outer casing 21 rotates, the scraper head 3 46, the scraper head 2 34 and the scraper head 1 26 dig and drill into the soil, and the drilled soil enters the inner casing 41, and is discharged through the curved plate 47 as the outer casing 21, the middle casing 31 and the inner casing 41 rotate.

[0043] The extension member includes a guide slider 51, a bulldozer head 52 is fixedly provided on one side of the guide slider 51, and the bulldozer head 52 is a triangle. A pull tube belt 53 is fixedly provided on one side of the bulldozer head 52 for pulling the middle casing 31 and the inner casing 41 to extend with the depth of drilling into the soil.

[0044] The extension piece also includes a guide groove 54 and a discharge hole 55, and both the middle casing 31 and the inner casing 41 are provided with a guide groove 54, and the guide groove 54 matches the corresponding guide slider 51. There are two groups of discharge holes 55, which are respectively opened on the cylinder walls of the middle casing 31 and the inner casing 41. The middle casing 31 and the inner casing 41 are always tightly pressed against the soil of the drilled hole under the pulling of their respective pull tube belts 53. As the soil is scraped, the guide slider 51 gradually moves forward, and the guide groove 54 slides along the guide groove 54. The bulldozer head 52 pushes out the soil in the guide groove 54. Finally, when pouring concrete, the concrete is diffused through the discharge hole 55, the soil entry hole 1 23, the soil entry hole 2 32 and the soil entry hole 3 43 to the travel route of the expanding head 1 24, the expanding head 2 33 and the expanding head 3 44, thereby increasing the supporting force of the anchor pulling mechanism 2 on the continuous retaining wall, and preventing the continuous retaining wall from tilting toward the center of the foundation pit after excavating the foundation pit.

[0045] Device installation and initial preparation:

[0046] First, in the preset foundation trench before excavating the continuous support wall, the main support 11 and the secondary support plate 12 are pre-installed. The main support 11 and the secondary support plate 12 are parallel to each other and close to the inner wall of the preset foundation trench. The two are supported in the positioning groove 13 and the positioning groove 2 15 by the pillar 14 to ensure the stability of the support structure.

[0047] Anchor pulling mechanism 2 ground drilling and expansion:

[0048] After the secondary support plate 12 and the main support plate 11 are installed, an external drill is used to connect the drill connection port 28. The drill drives the outer casing 21 to rotate through the connecting frame 27 and the top plate ring 22. The expansion head 24 on the outer casing 21 rotates out under the elastic force of the torsion spring, and the soil is scraped as it rotates, forming a spiral travel route. At the same time, the scraper head 26 digs the soil, and the drilled soil enters the inner casing 41 and is discharged through the curved plate 47 as the outer casing 21 rotates.

[0049] As the outer casing 21 goes deeper, the travel path of the expansion head 1 24 gradually deepens, forming a deep groove with a diameter greater than the diameter of the outer casing 21. When the outer casing 21 is extended to the maximum value, the middle casing 31 and the inner casing 41 start to work, and the expansion parts, the expansion head 2 33 and the expansion head 3 44 and the scraper head 2 34 and the scraper head 3 46 thereon also scrape and dig the soil, forming a deeper and wider thread groove.

[0050] During the drilling process, the guide slider 51, the bulldozer head 52 and the pull tube belt 53 play a key role. The bulldozer head 52 is a triangular body that can push out the soil in the guide groove 54. At the same time, the pull tube belt 53 pulls the middle casing 31 and the inner casing 41 to extend with the depth of drilling into the soil, ensuring the overall stability of the anchor pulling mechanism 2.

[0051] Concrete pouring and integrated structure formation:

[0052] When the outer casing 21, the middle casing 31 and the inner casing 41 are deeply embedded in the soil, the concrete is filled into the threaded grooves to make the concrete closely combined with the outer casing 21, the middle casing 31 and the inner casing 41 to form an integrated structure. At the same time, the concrete is diffused into the travel routes of the expansion head 1 24, the expansion head 2 33 and the expansion head 3 44 through the discharge hole 55, the soil inlet hole 1 23, the soil inlet hole 2 32 and the soil inlet hole 3 43, further increasing the supporting force of the anchoring mechanism 2.

[0053] Retaining wall construction and support:

[0054] After the anchoring mechanism 2 forms an integrated structure, the construction of the continuous retaining wall begins. As the anchoring mechanism 2 drills into the soil in a direction away from the center of the foundation pit and pours concrete, a lateral side support for the continuous retaining wall is formed. This support method can effectively prevent the continuous retaining wall from tilting toward the center of the foundation pit during excavation, thereby improving the safety and stability of the foundation pit excavation.

[0055] The above describes an embodiment of the present embodiment, but the present embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present embodiment, ordinary technicians in this field can also make many forms, all of which are within the protection of the present embodiment.

Claims

1. A support device for excavating a foundation pit on a plateau with soft foundation, characterized in that: include: A main support (11), the main support (11) being pre-installed in a preset foundation trench before excavating a continuous retaining wall, and an anchoring mechanism (2) being arranged at the center of the main support (11); the anchoring mechanism (2) being used to drill into the soil in a direction away from the center of the foundation pit, and to pour concrete after drilling into the soil to form an integrated structure with the subsequent retaining wall, thereby realizing lateral side tension support for the continuous retaining wall; The anchor pulling mechanism (2) specifically comprises an outer casing (21), a middle casing (31) and an inner casing (41); the inner casing (41) can slide inside the middle casing (31), and the middle casing (31) can also slide inside the outer casing (21), thereby forming a multi-level nested combined structure with telescopic function; extension pieces are respectively provided at the nested ends of the outer casing (21), the middle casing (31) and the inner casing (41), and the outer walls of the three are equipped with diameter expansion pieces; The expansion member is drilled into the soil as the outer casing (21), the middle casing (31) and the inner casing (41) rotate in the same direction, forming a threaded path, and then the threaded grooves are filled with concrete, so that the concrete, the outer casing (21), the middle casing (31) and the inner casing (41) are tightly combined to form an integrated structure; The expansion member comprises a soil entry hole 1 (23), an expansion head 1 (24), a soil entry hole 2 (32), an expansion head 2 (33), a soil entry hole 3 (43), and an expansion head 3 (44); the soil entry hole 1 (23) and the expansion head 1 (24) form a group and are arranged on the outer casing (21); the soil entry hole 2 (32) and the expansion head 2 (33) form a group and are arranged on the middle casing (31); the soil entry hole 3 (43) and the expansion head 3 (44) form a group and are arranged on the inner casing (41); The first expansion head (24) is arranged in the first soil entry hole (23) through a torsion spring, the second expansion head (33) is arranged in the second soil entry hole (32) through a torsion spring, and the third expansion head (44) is arranged in the third soil entry hole (43) through a torsion spring; The extension member comprises a guide slider (51), a bulldozer head (52) is fixedly provided on one side of the guide slider (51), and the bulldozer head (52) is a triangular body, and a pull tube belt (53) is fixedly provided on one side of the bulldozer head (52) for pulling the middle casing (31) and the inner casing (41) to extend as the depth of drilling into the soil increases; The extension piece further comprises a guide groove (54) and a discharge hole (55), and the guide groove (54) is provided in both the middle casing (31) and the inner casing (41), and the guide groove (54) matches the corresponding guide slider (51), and two groups of the discharge holes (55) are provided, which are respectively opened in the walls of the middle casing (31) and the inner casing (41).

2. A supporting device for excavation of foundation pit in soft plateau soil according to claim 1, characterized in that: The main support (11) comprises a secondary support plate (12), the secondary support plate (12) and the main support (11) are parallel to each other, and the secondary support plate (12) is also pre-installed in a preset foundation trench before excavating the continuous support wall, the secondary support plate (12) and the main support (11) are respectively closely attached to the inner wall of the preset foundation trench, and the main support (11) is on a side away from the center point of the foundation pit.

3. A supporting device for excavation of foundation pit in soft plateau soil according to claim 2, characterized in that: The main support (11) has two mutually parallel and symmetrical positioning grooves (15) on its inner side, and the auxiliary support plate (12) has two mutually parallel and symmetrical positioning grooves (13) on its inner side. The positioning grooves (13) and (15) are aligned with each other, and a support column (14) is provided between the positioning grooves (13) and (15).

4. The supporting device for excavation of foundation pit in soft plateau soil according to claim 1 is characterized in that: A bearing body (6) is arranged inside the main support (11), the outer casing (21) passes through the center of the bearing body (6), and the outer ring wall of the bearing body (6) is fixedly connected to the main support (11), and a top plate ring (22) is fixedly arranged at one end of the outer casing (21) close to the preset base groove, and a plurality of bolt holes (25) are opened on the outer ring of the top plate ring (22) for fixing the outer casing (21) and the bearing body (6) with bolts after the outer casing (21), the middle casing (31) and the inner casing (41) are completely drilled into the soil.

5. The supporting device for excavation of foundation pit in soft plateau soil according to claim 4 is characterized in that: A drilling rig connection port (28) is fixedly provided at the center position of the top plate ring (22), and a cross-shaped connection frame (27) is fixedly provided between the drilling rig connection port (28) and the top plate ring (22). The centers of the top plate ring (22), the drilling rig connection port (28) and the bearing body (6) coincide with each other. The drilling rig connection port (28) is used for an external drilling rig to provide power for the outer casing (21), the middle casing (31) and the inner casing (41) to drill into the soil.

6. The supporting device for excavation of foundation pit in soft plateau soil according to claim 1 is characterized in that: A scraper head 1 (26) is fixedly provided at one end of the outer casing (21) away from the preset base groove, a scraper head 2 (34) is fixedly provided at one end of the middle casing (31) and the outer casing (21) away from the preset base groove, a curved plate (47) is fixedly provided inside the inner casing (41), a pressure plate (45) is fixedly provided at one end of the curved plate (47), and a scraper head 3 (46) is fixedly provided on the other side of the pressure plate (45), and the scraper head 3 (46), the scraper head 2 (34) and the scraper head 1 (26) are aligned with each other and arranged in a straight line.

Images