Blade foot structure for open caisson construction under rock geology and construction method

Abstract

The invention relates to the technical field of rotational flow well construction, in particular to a blade foot structure for open caisson construction under rock geology and a construction method. Comprising an outer wall, an inner wall and a bottom tread, an inclined plane is obliquely arranged between the tread and the lower end of the inner wall, the bottom of the outer wall is of a protruding two-layer step structure, and a concave fixing groove is formed in the bottom of the inner wall. The construction cost is saved, the open caisson speed is increased, the construction period is shortened, the construction measure cost is saved, the bottom blade foot structure is enlarged, dynamic balance in the open caisson process is guaranteed, inclination out-of-tolerance is not prone to occurring, and the cylinder wall perpendicularity and the overall levelness are easy to control.

Description

Technical Field

[0001] The invention relates to the technical field of vortex well construction, in particular to a blade foot structure and a construction method for rock geological well construction. Background Art

[0002] In the field of domestic metallurgical construction, vortex wells play an important role. As underground structures, vortex wells have the characteristics of large diameter (about 18~35m), thick tube wall (about 1~1.5m), and deep foundation pit (about 20~35m), which are the key and difficult points in construction.

[0003] Common vortex well structure construction methods include slope excavation forward method, reverse method, and caisson method. Comprehensively comparing the above construction methods, the caisson method has the shortest construction period and the most obvious economic benefits.

[0004] However, in the process of caisson construction, it is difficult to control the overall verticality and horizontality of the outer tube wall. Especially when there are rocks in the caisson, the following problems exist in the conventional blade foot construction method: 1. The outer cylinder wall is in direct contact with the soil, and the friction is large, so external force is generally needed to assist sinking; 2. During the caisson process, tilt deviation is prone to occur, and the verticality quality of the caisson is difficult to control; 3. The rock on the outside of the cylinder wall is easy to collide with the cylinder wall, causing local deformation of the cylinder wall and affecting the construction quality. Summary of the invention

[0005] The present invention aims to solve the above-mentioned problem, thereby providing a blade foot structure and a construction method for rock geological caisson construction which can shorten the construction period.

[0006] The present invention solves the above-mentioned problem by adopting the following technical solution: A blade foot structure for rock geological sinking well construction comprises an outer wall, an inner wall and a tread at the bottom, an inclined surface is arranged obliquely between the tread and the lower end of the inner wall, the bottom of the outer wall presents a convex two-layer step structure, and the bottom of the inner wall is provided with a concave fixing groove.

[0007] A construction method of a blade foot structure for rock geological caisson construction comprises the following steps: S1: Blade foot brick membrane is laid and blade foot steel guard plate is installed.

[0008] S2: Construction of the first section of the cylinder wall with blade feet.

[0009] S3: Construction of the first section of the cylinder wall caisson.

[0010] S4: Construction of upper cylinder wall.

[0011] S5: The caisson bottom is sealed and the inner tube superstructure is constructed.

[0012] S6: Fill the gaps in the caisson with sand and make it dense.

[0013] Compared with the prior art, the present invention adopting the above technical solution has the following outstanding features: Compared with the rock reverse construction method, the present invention avoids the construction of the front row of piles and saves construction cost; compared with the conventional caisson method, the present invention reduces the friction between the large-area outer cylinder wall and the soil, improves the caisson speed, saves construction period, avoids the situation in which the outer cylinder wall collides and deforms with the rock layer and becomes difficult to sink during the conventional caisson, does not need to adopt other sinking-aiding methods, saves construction measures cost, and the bottom blade foot structure is enlarged to ensure its dynamic balance during the caisson process, is not prone to tilt deviation, and the verticality of the cylinder wall and the overall horizontality are easy to control.

[0014] Preferably, a further technical solution of the present invention is: Furthermore, the inclined surface, the tread surface and the step side surfaces of the lower section of the outer wall are wrapped with steel guard plates.

[0015] Furthermore, in S1, before the brick membrane is constructed, a 100 mm C20 concrete cushion layer is poured to ensure the flatness of the ground.

[0016] Furthermore, the lower section of the stepped structure of the blade foot is 200 mm thicker than the outer wall of the vortex well.

[0017] Furthermore, the upper section of the stepped structure of the blade foot is 100 mm thicker than the outer wall of the vortex well. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the main cross-sectional structure of an embodiment of the present invention during construction; Figure 2 It is a schematic diagram of the cross-sectional structure of the blade foot of an embodiment of the present invention; Markings in the figure are: blade foot 1, fixing groove 21, outer wall 22, inner wall 23, tread 24, caisson bottom sealing bottom plate 2, cylinder wall 3, rock layer 4, soil 5, steel guard plate 6. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with embodiments, the purpose of which is only to provide a better understanding of the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

[0020] A blade foot structure for caisson construction in rock geology comprises an outer wall 22, an inner wall 23 and a tread 24 at the bottom, an inclined surface is obliquely arranged between the tread 24 and the lower end of the inner wall 23, the bottom of the outer wall 22 is a convex two-layer stepped structure, the bottom of the inner wall 23 is provided with a concave fixing groove 21, and the caisson bottom sealing bottom plate 2 is placed between the fixing grooves 21.

[0021] The inclined surface, the tread surface and the step side surfaces of the lower section of the outer wall are wrapped with steel guard plates 6.

[0022] The bottom of the conventional cylindrical blade foot 1 is enlarged and changed into a stepped blade foot 1 structure, so that the weight of the bottom of the blade foot 1 is greater than the weight of the upper section of the same level, and the overall center of gravity is moved downward, so that it is not easy to tilt excessively during the caisson process; the outer wall 22 of the blade foot 1 is made into a stepped shape, so that the outer diameter of the bottom is greater than the outer diameter of the upper part, so that during the caisson process, the contact area between the cylinder wall 3 and the outer soil 5 is greatly reduced, so as to achieve the purpose of smooth and rapid sinking; during the caisson construction, when encountering the rock layer 4, in order to ensure the strength of the blade foot 1, a steel guard plate 6 is added to the lower section of the outer wall 22 of the blade foot 1 to protect the blade foot 1.

[0023] A construction method of a blade foot 1 structure for rock geological caisson construction comprises the following steps: S1: Blade foot 1 brick membrane is built, and blade foot 1 steel guard plate 6 is installed. Before the brick membrane is constructed, a 100mm C20 concrete cushion is poured to ensure the flatness of the ground, which is convenient for the subsequent construction to control the verticality and horizontality of the cylinder wall. Then the blade foot 1 steel guard plate 6 is laid, and then the brick membrane is built.

[0024] S2: Construction of the first section of the cylinder wall 3 with blade foot 1. According to the requirements of the drawings, the first section of the cylinder wall 3 with blade foot 1 is subjected to reinforcement and formwork, welding and installation of the joint water-stop steel plate, concrete pouring, and structural maintenance. The lower section of the stepped structure of the blade foot 1 is 200mm thicker than the outer cylinder wall 3 of the vortex well, and a steel guard plate 6 is added on the outside. The upper section of the stepped structure of the blade foot 1 is 100mm thicker than the outer cylinder wall 3 of the vortex well. The specific thickness increase can be appropriately adjusted according to the geological conditions of the geological survey report (when the rock layer is thick, its thickness can be appropriately increased to ensure the structural rigidity of the blade foot 1; otherwise, its thickness can be appropriately reduced); when pouring the cylinder wall 3, it should be poured in layers along one direction, and the thickness of each layer should be controlled within 500mm, and vibrated to compact.

[0025] S3: Caisson construction of the first section of the cylinder wall 3. When the concrete of the first section of the cylinder wall 3 reaches the designed strength, caisson construction can be carried out. During the caisson process, since the outer diameter of the bottom is larger than the outer diameter of the upper part, there is a gap between the outer cylinder wall 3 and the soil 5, which greatly reduces the friction between the two. The gravity of the cylinder structure is larger than the friction between the two. During the excavation process, the cylinder wall sinks automatically. When the first section (cylinder wall sinks to a height of 0.5m~1m above the ground, stop excavation and sink.

[0026] S4: Construction of the upper cylinder wall 3. According to the design requirements, the second and third steps are repeated in sections until the bottom elevation required by the design is reached, and the caisson construction is terminated.

[0027] S5: The caisson bottom is sealed and the inner tube superstructure is constructed. When the caisson reaches the designed bottom elevation, the bottom is sealed according to the requirements of the drawings, and then the inner tube superstructure is constructed until the structure is capped.

[0028] S6: The gaps in the caisson are filled with sand and compacted. After the structural construction is completed, there is a gap of about 200 mm between the outer cylinder wall 3 and the soil 5. In order to ensure its structural stability, the sand filling method is used to seal the gap.

[0029] This method does not require other sinking-aiding measures. The strength and stiffness of the cylinder wall 3 at the bottom of the blade foot 1 are increased, and the collision between the cylinder wall 3 and the outer rock mass is greatly reduced. The sinking speed is fast and it is not easy to tilt. The quality of caisson construction is improved, the construction period is shortened, and the effect is remarkable. Compared with the rock reverse construction method, the construction of the front row of piles is avoided, and the construction cost is saved. Compared with the conventional caisson method, the friction between the large-area outer cylinder wall 3 and the soil 5 is reduced, the caisson speed is increased, the construction period is saved, and the situation that the outer cylinder wall 3 and the rock layer 4 collide and deform and become difficult to sink during conventional caisson is avoided. No other sinking-aiding methods are required, and the cost of construction measures is saved. The structure of the bottom blade foot 1 is enlarged to ensure its dynamic balance during the caisson process, and it is not easy to tilt beyond the tolerance. The verticality and overall horizontality of the cylinder wall 3 are easy to control.

[0030] The above description is only a preferred feasible embodiment of the present invention, and does not limit the scope of rights of the present invention. All equivalent changes made using the contents of the present specification and its drawings are included in the scope of rights of the present invention.

Claims

1. A blade foot structure for rock geological sinking well construction, comprising an outer wall, an inner wall and a tread at the bottom, an inclined surface is arranged between the tread and the lower end of the inner wall, and is characterized in that: The bottom of the outer wall is in a convex two-layer stepped structure, and the bottom of the inner wall is provided with a concave fixing groove.

2. The blade foot structure for rock geological well construction according to claim 1 is characterized by: The ramps, treads and step sides of the lower section of the outer wall are covered with steel guard plates.

3. A construction method of a blade foot structure for rock geological caisson construction using any one of claims 1-2, characterized in that: The steps include: S1: Blade foot brick membrane masonry, and installation of blade foot steel guard plate; S2: Construction of the first section of the tube wall with blade feet; S3: Construction of the first section of the cylinder wall caisson; S4: upper tube wall construction; S5: caisson bottom sealing and inner tube superstructure construction; S6: Fill the gaps in the caisson with sand and make it dense.

4. The construction method of the blade foot structure for rock geological caisson construction according to claim 3, characterized in that: In S1, before the construction of the brick membrane, a 100mm C20 concrete cushion layer was poured to ensure the flatness of the ground.

5. The construction method of the blade foot structure for rock geological caisson construction according to claim 3 is characterized by: The lower section of the stepped structure of the blade foot is 200mm thicker than the outer wall of the vortex well.

6. The construction method of the blade foot structure for rock geological caisson construction according to claim 3 is characterized by: The upper section of the stepped structure of the blade foot is 100mm thicker than the outer wall of the vortex well.

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