A caisson sinking aid structure and its use process

Abstract

The present invention relates to the technical field of caissons, and in particular to a caisson sinking aid structure and a use process thereof, wherein the steel blade foot comprises a steel blade foot outer tube, a steel blade foot tread surface and a steel blade foot reinforcing rib, wherein the upper portion of the steel blade foot outer tube is connected to the caisson wall, the middle portion of the steel blade foot outer tube is connected to the steel blade foot tread surface, the lower portion of the steel blade foot outer tube is connected to the steel blade foot reinforcing rib, the top surface of the steel blade foot tread surface is connected to the caisson wall, the bottom surface of the steel blade foot tread surface is connected to the steel blade foot reinforcing rib, and the bottom of the steel blade foot reinforcing rib is provided with a taper; a water jetting device, wherein the water jetting device comprises a plurality of high-pressure water pipes and a high-pressure water nozzle, the high-pressure water pipes are connected to the high-pressure water nozzle, the high-pressure water pipes are arranged along the inner wall of the well wall, the high-pressure water nozzle is arranged between two steel blade foot reinforcing ribs, and the steel blade foot performs two operations during the sinking process of the caisson, namely, it can effectively cut the soil and timely separate the soil inside and outside the caisson; and secondly, when the soil under the caisson blade foot is hollowed out, the soil outside the caisson is not easy to enter the caisson along the blade foot end surface.

Description

Technical Field

[0001] The invention relates to the technical field of caissons, in particular to a caisson sinking aid structure and a use process thereof. Background Art

[0002] During the sinking process of the caisson in soft soil and interlayered sand and soil, the blade foot is subjected to a dramatic change in vertical upward resistance, which may cause the caisson to fail to sink or sink suddenly; when the caisson passes through the soft soil layer during the sinking process, the soft soil outside the caisson enters the caisson under the action of the soil pressure difference inside and outside the caisson, resulting in a large amount of soil excavation work and ground collapse outside the caisson; when the caisson tread is on the sandy soil layer, the caisson is not easy to sink due to the large bearing capacity of the sandy soil layer. If the blade foot is used to dig more soil to assist sinking, it is easy to cause a large amount of sand outside the caisson to enter the caisson, which will increase the amount of excavated soil on the one hand, and cause the ground outside the caisson to collapse and create danger on the other hand. The caisson additional steel blade foot device described in the present invention can firstly adapt to soft soil and interlayered sand and soil, and is not easy to form the phenomenon of difficulty in sinking or sudden sinking during the effective soil cutting and sinking process; secondly, it can effectively prevent a large amount of sand outside the caisson from entering the caisson during the sinking process of soft soil and sandy soil layers.

[0003] Among them, 1. Soft soil: fine-grained soil with a natural porosity greater than or equal to 1.0 and a natural water content greater than the liquid limit, including silt, silty soil, peat, and peaty soil. 2. Sandy soil: soil in which the mass of particles with a particle size greater than 2 mm does not exceed 50% of the total mass, and the mass of particles with a particle size greater than 0.075 mm exceeds 50% of the total mass. 3. Caisson: an underground structure in which a shaft is made on the ground and the soil is taken from the shaft to sink to a predetermined depth underground. 4. Blade foot: the part with an inclined surface at the lower end of the caisson wall panel, used to support the weight of the caisson and the sinking of cut soil. 5. Caisson tread: the flat layer where the bottom of the caisson blade foot is in contact with the soil layer. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and to provide a caisson sinking aid structure and a use process thereof.

[0005] In order to achieve the above-mentioned purpose, a caisson sinking aid structure is designed, including a caisson wall, the bottom of the caisson wall is provided with a taper to form a caisson blade foot, which is characterized in that it includes: a steel blade foot, the steel blade foot includes a steel blade foot outer tube, a steel blade foot tread and a steel blade foot reinforcing rib, the upper part of the steel blade foot outer tube is connected to the caisson wall, the middle part of the steel blade foot outer tube is connected to the steel blade foot tread, the lower part of the steel blade foot outer tube is connected to the steel blade foot reinforcing rib, the top surface of the steel blade foot tread is connected to the caisson wall, the bottom surface of the steel blade foot tread is connected to the steel blade foot reinforcing rib, and the bottom of the steel blade foot reinforcing rib is provided with a taper; a water jetting device, the water jetting device includes a plurality of high-pressure water pipes and high-pressure water nozzles, the high-pressure water pipes are connected to the high-pressure water nozzles, the high-pressure water pipes are arranged along the inner wall of the well wall, and the high-pressure water nozzles are arranged between two steel blade foot reinforcing ribs.

[0006] Preferably, the steel blade foot also includes a steel blade foot anchor, the outer tube of the steel blade foot is connected to the caisson wall via the steel blade foot anchor, and the tread surface of the steel blade foot is connected to the caisson wall via the steel blade foot anchor.

[0007] Preferably, the steel blade foot anchor is a π-shaped structure made of round steel with a diameter of 20 mm.

[0008] Preferably, the outer cylinder of the steel blade foot is made of a 30 mm thick steel plate.

[0009] Preferably, the steel blade tread is made of 25 mm steel plate.

[0010] Preferably, the steel blade foot reinforcement ribs are made of 25 mm steel plates and are evenly arranged at intervals of 800 mm along the caisson wall.

[0011] Preferably, the high-pressure water pipe is a seamless steel pipe with an outer diameter of 50 mm and a wall thickness of 5 mm, and is evenly arranged at intervals of 800 mm along the wall of the caisson. Each of the high-pressure water pipes is provided with an independent switch.

[0012] Preferably, the high-pressure water nozzles are rectangular with a height of 15 mm and a width of 75 mm, and are evenly arranged at intervals of 800 mm along the caisson wall.

[0013] The use process of the above-mentioned caisson sinking aid structure is as follows:

[0014] a. Sinking wells in soft soil.

[0015] Above the groundwater level, the water is drained and sunk. If the soil inside the caisson bulges, a soil plug is left in the caisson for ballast. At this time, the high-pressure water nozzle is started to lubricate the inner wall of the caisson, reducing or even eliminating the friction between the soil inside the caisson and the inner wall of the caisson.

[0016] Below the groundwater, it sinks without drainage;

[0017] b. Caisson in sandy soil layer,

[0018] Above the groundwater level, the water is drained and the sand and soil under the steel blade foot are cleared. At this time, the lower part of the outer tube of the steel blade foot has been pressed into the sand and soil, preventing the sand and soil outside the caisson from entering the caisson, reducing the amount of soil taken for caisson construction, and reducing the risk of earthwork collapse outside the caisson.

[0019] Below the groundwater, the caisson sinks without drainage. Start the high-pressure water nozzle, and the high-speed water flow carries the sand and soil out of the end of the steel blade foot tread, reducing the area of ​​the steel blade foot tread contacting the sand and soil, reducing the resistance of the blade foot tread, and making the caisson sink. At this time, the outer tube of the steel blade foot prevents the sand and soil outside the caisson from entering the caisson;

[0020] c. When the caisson shows a sinking deviation, open the high-pressure water nozzle on the side with smaller settlement to reduce the contact area between the steel blade foot surface and the soil on this side, reduce the sinking resistance at this position, increase the sinking amount at this position, and achieve the purpose of correction.

[0021] In the prior art: 1. The purpose of using angle steel or steel plate welded corner guards on the caisson blade is to protect the concrete blade from being damaged during the sinking process of hard soil, gravel and weathered rock formations; 2. The purpose of conventional water jetting to aid sinking is to loosen the soil near the caisson blade, which is conducive to the sinking of the caisson.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. The purpose of using angle steel or steel plate to weld the corner guard on the caisson blade foot is to protect the concrete blade foot from being damaged during the sinking process of hard soil, gravel and weathered rock formations, and has no regulating effect on the change of the sinking resistance of the caisson. When encountering soft soil or sand layer, the steel corner guard has no additional blocking effect on the sand outside the caisson entering the caisson; the steel blade foot of the present invention has two functions during the sinking process of the caisson. First, it can effectively cut the soil and separate the soil inside and outside the caisson in time; second, when the soil under the caisson blade foot is hollowed out, the soil outside the caisson is not easy to enter the caisson along the end surface of the blade foot;

[0024] 2. The purpose of conventional water jetting to aid sinking is to loosen the soil near the blade foot of the caisson, which is conducive to the sinking of the caisson. There is no control requirement for the flow direction of the water carrying sand and soil, and it cannot directional transport the soil loosened by impact; the horizontal nozzle in the steel blade foot can adjust the water pressure of the nozzle according to the soil conditions and the sinking speed requirements of the caisson, so that the water flow carries different amounts of soil into the caisson without affecting the soil outside the caisson. At the same time, the contact area between the caisson blade foot tread and the soil can be adjusted by the amount of soil flushed by the water flow, thereby achieving the purpose of adjusting the sinking resistance of the caisson. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the present invention;

[0026] Figure 2 It is a cross-sectional view of II of the present invention;

[0027] In the figure: 1. Caisson wall 2. High-pressure water pipe 3. Steel blade foot anchor 4. High-pressure water nozzle 5. Steel blade foot outer tube 6. Caisson blade foot tread surface 7. Steel blade foot tread surface 8. Steel blade foot reinforcement rib. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with the accompanying drawings, and the structure and principle of the present invention are very clear to people in the field. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] See also Figure 1 and Figure 2 The present invention provides a caisson sinking aid structure, including a caisson wall, wherein the bottom of the caisson wall is provided with a taper to form a caisson blade foot, and is characterized in that it includes: a steel blade foot, wherein the steel blade foot includes a steel blade foot outer tube, a steel blade foot step surface and a steel blade foot reinforcing rib, wherein the upper portion of the steel blade foot outer tube is connected to the caisson wall, the middle portion of the steel blade foot outer tube is connected to the steel blade foot step surface, the lower portion of the steel blade foot outer tube is connected to the steel blade foot reinforcing rib, the top surface of the steel blade foot step surface is connected to the caisson wall, the bottom surface of the steel blade foot step surface is connected to the steel blade foot reinforcing rib, and the bottom of the steel blade foot reinforcing rib is provided with a taper; a water jetting device, wherein the water jetting device includes a plurality of high-pressure water pipes and a high-pressure water nozzle, the high-pressure water pipe is connected to the high-pressure water nozzle, the high-pressure water pipe is arranged along the inner wall of the well wall, and the high-pressure water nozzle is arranged between two steel blade foot reinforcing ribs. The steel blade foot also includes a steel blade foot anchor, the outer tube of the steel blade foot is connected to the caisson wall through the steel blade foot anchor, and the steel blade foot tread is connected to the caisson wall through the steel blade foot anchor.

[0030] The steel blade foot cuts the soil, transmits soil pressure, and prevents the soil outside the caisson from entering the caisson. The horizontal water jet device adjusts the contact area between the blade foot tread and the soil and flushes the soil on the bottom of the blade foot tread. The specific parts are described as follows:

[0031] 1. The caisson wall is usually a reinforced concrete structure and is an important part of the caisson. After the caisson wall is sunk into the soil layer, the soil in the caisson is taken away to form an underground space, which can be used as a subsequent foundation construction space or as an underground structure. Steel box structures can also use this process technology.

[0032] 2. High-pressure water pipe, a seamless steel pipe with an outer diameter of 50mm and a wall thickness of 5mm, serves as a high-pressure water flow channel to transport high-pressure water from the ground to the high-pressure water nozzle. Each high-pressure water pipe has an independent switch on the ground and is evenly arranged at intervals of 800mm along the inner wall of the caisson.

[0033] 3. The steel blade foot anchor is made of π-shaped round steel with a diameter of 20. It is fully welded along the top of the outer tube of the steel blade foot and the innermost side of the steel blade foot tread with a spacing of 1000mm to connect the special steel blade foot and the concrete caisson wall into a whole. The specific dimensions are: the length of the welded part with the steel blade foot is 150mm, the length of the straight section penetrating into the concrete is 200mm, and the length of the hook section is 150mm.

[0034] 4. High-pressure water nozzle, the high-pressure water delivered by the high-pressure water pipe is horizontally flushed to the inside of the caisson along the steel blade foot tread surface. The high-pressure water flow can wash the soil below the tread out of the tread surface. According to the soil conditions and the planned sinking speed of the caisson, the water pressure can be adjusted to change the water flow rate, so as to achieve the purpose of adjusting the contact area between the blade foot tread surface and the soil. When the contact area is large, the resistance on the tread becomes larger, and the sinking resistance of the caisson becomes larger; when the contact area is small, the resistance on the tread becomes smaller, and the sinking resistance of the caisson becomes smaller. It is evenly arranged at a spacing of 800mm along the inner wall of the caisson, arranged between the two steel blade foot reinforcement ribs, and the nozzle is a rectangle with a height of 15mm and a width of 75mm.

[0035] 5. The outer tube of the steel blade foot, the upper part of the outer tube is connected to the caisson wall through the steel blade foot anchor, the middle part is connected to the steel blade foot tread by welding, and the lower part is connected to the steel blade foot reinforcement rib by welding. The outer tube of the steel blade foot has two main functions: one is to cut the soil, separate the soil inside and outside the caisson in time, and prevent the soil outside the caisson from entering the caisson along the end face of the blade foot; the other is that when the high-pressure nozzle sprays water at high speed to flush the soil, the turbulent water flow will not affect the soil outside the caisson. The outer tube of the steel blade foot is made of 30mm thick steel plate.

[0036] 6. The caisson blade foot tread bears the soil pressure and provides resistance to the caisson's sinking. When the steel blade foot of the present invention is used, the widest tread of the blade foot can be set to be the same width as the caisson wall, which can provide a higher resistance to the caisson's sinking.

[0037] 7. The steel blade foot tread is connected to the caisson wall through the steel blade foot anchor and welded to the outer tube of the steel blade foot on the outside. The steel blade foot tread has two functions: one is to separate the water flow ejected by the high-pressure water nozzle from the concrete blade foot tread to prevent the soil carried by the high-pressure water flow from eroding the concrete tread; the other is to strengthen the rigidity of the steel blade foot outer tube by welding the steel blade foot reinforcement rib to the steel blade foot outer tube. The steel blade foot tread is made of 25mm thick steel plate.

[0038] 8. The steel blade foot reinforcement ribs are connected to the steel blade foot outer tube and the steel blade foot tread surface through welding to form a whole, forming the special steel blade foot of the present invention. The function of the steel blade foot reinforcement ribs is to divide the lower area of ​​the blade foot into compartments of the same width to avoid the mutual influence of high-pressure water flows sprayed from the high-pressure water nozzles. The ribs are evenly arranged at intervals of 800mm along the inner wall of the caisson, and the steel plate thickness is 25mm.

[0039] The above-mentioned caisson sinking aid structure can realize caisson in the interlayer of soft soil and sand, soft soil and sand. The difficulty of caisson in the interlayer of soft soil and sand is that the soft soil foundation has low bearing capacity and the sand foundation has large bearing capacity, and the difference between the two is large. If the width of the blade foot tread of the concrete caisson is designed to be larger according to the soft soil layer, the blade foot tread will be subject to large resistance in the sand layer, and the caisson will be difficult to sink. At this time, if the contact area between the tread and the sand is reduced by digging more sand near the blade foot, the resistance of the tread will be reduced, and the sand outside the caisson will easily enter the caisson from the bottom of the tread, causing the soil around the caisson to collapse and form a safety accident. This problem is more serious below the groundwater level. If the width of the blade foot tread of the concrete caisson is designed to be smaller according to the sand layer, the blade foot tread will be subject to too little resistance in the soft soil layer, and the caisson will easily cause a sudden sinking accident. The specific caisson process is as follows:

[0040] 1. Caisson in soft soil. Above the groundwater level, conventional drainage sinking technology can be adopted. If drainage sinking causes the soil inside the caisson to bulge, a soil plug can be left in the caisson for ballast. At this time, the high-pressure water nozzle is started to lubricate the inner wall of the caisson, reducing or even eliminating the friction between the soil inside the caisson and the inner wall of the caisson. Because the lower part of the outer tube of the steel blade foot blocks the water flow, the high-pressure water flow will not affect the soil outside the caisson. Below the groundwater, conventional non-drainage sinking can be adopted.

[0041] 2. Caisson in sandy soil layer. Above the groundwater level, conventional drainage sinking technology can be adopted. In order to reduce the area of ​​the blade foot tread contacting the sand and soil, the sand and soil under the blade foot can be cleared. At this time, since the lower part of the outer tube of the steel blade foot has been pressed into the sand and soil, the sand and soil outside the caisson can be prevented from entering the caisson, reducing the amount of soil taken for caisson construction and the risk of earth collapse outside the caisson. Below the groundwater, conventional non-drainage sinking is adopted. The high-pressure water nozzle is started. The high-speed water flow carries the sand and soil out of the end of the blade foot tread, reducing the area of ​​the blade foot tread contacting the sand and soil, reducing the resistance of the blade foot tread, and causing the caisson to sink. At this time, the outer tube of the steel blade foot can prevent the sand and soil outside the caisson from entering the caisson. By adjusting the water pressure, the area of ​​the blade foot tread contacting the sand and soil can be adjusted to adapt to sand layers with different bearing capacities.

[0042] 3. For caissons in soft soil layers, use the B process.

[0043] 4. For caissons in sandy soil layers, the C process is used.

[0044] 5. Caisson correction: The steel blade foot of the present invention is used in conjunction with the horizontal water jetting to assist the sinking of the caisson. In addition to the conventional caisson correction method, an efficient correction method is also provided. When the caisson has a sinking deviation, a high-pressure water nozzle is opened on the side with a smaller settlement amount to reduce the contact area between the blade foot tread and the soil on this side, reduce the sinking resistance at this position, and increase the sinking amount at this position, thereby achieving the purpose of correction.

[0045] The present invention can also have the following variations:

[0046] 1. Use reinforced concrete structure to replace the outer tube of steel blade foot;

[0047] 2. Install the high-pressure nozzle horizontally and change it to spray water vertically downward;

[0048] 3. Changes in the thickness of the steel blade foot, nozzle size, and high-pressure water pipe material;

[0049] 4. Changes in the spacing of high-pressure water nozzles.

Claims

1. A caisson sinking aid structure, comprising a caisson wall, wherein the bottom of the caisson wall is provided with a taper to form a caisson blade foot, characterized in that include: A steel blade foot, the steel blade foot comprises a steel blade foot outer tube, a steel blade foot tread surface and a steel blade foot reinforcing rib, the upper portion of the steel blade foot outer tube is connected to the caisson wall, the middle portion of the steel blade foot outer tube is connected to the steel blade foot tread surface, the lower portion of the steel blade foot outer tube is connected to the steel blade foot reinforcing rib, the top surface of the steel blade foot tread surface is connected to the caisson wall, the bottom surface of the steel blade foot tread surface is connected to the steel blade foot reinforcing rib, and the bottom of the steel blade foot reinforcing rib is provided with a taper; A water jet device, the water jet device comprises a plurality of high-pressure water pipes and high-pressure water nozzles, the high-pressure water pipes are connected to the high-pressure water nozzles, the high-pressure water pipes are arranged along the inner wall of the well wall, the high-pressure water nozzles are arranged between two steel blade foot reinforcement ribs, the high-pressure water pipes are seamless steel pipes with an outer diameter of 50mm and a wall thickness of 5mm, and are evenly arranged at intervals of 800mm along the well wall of the caisson, and each of the high-pressure water pipes is provided with an independent switch; The high-pressure water nozzle directs the high-pressure water delivered by the high-pressure water pipe horizontally toward the inside of the caisson along the steel blade foot tread surface. The high-pressure water flow can wash the soil below the steel blade foot tread surface out of the steel blade foot tread surface. The water pressure can be adjusted to change the water flow rate according to the soil conditions and the planned sinking speed of the caisson, so as to achieve the purpose of adjusting the contact area between the steel blade foot tread surface and the soil.

2. A caisson sinking aid structure as claimed in claim 1, characterized in that: The steel blade foot also includes a steel blade foot anchor, the outer tube of the steel blade foot is connected to the caisson wall through the steel blade foot anchor, and the steel blade foot tread is connected to the caisson wall through the steel blade foot anchor.

3. A caisson sinking aid structure as claimed in claim 2, characterized in that: The steel blade foot anchor is a π-shaped structure made of round steel with a diameter of 20 mm.

4. The caisson sinking aid structure according to claim 1, characterized in that: The outer cylinder of the steel blade foot is made of a 30mm thick steel plate.

5. The caisson sinking aid structure according to claim 1, characterized in that: The steel blade tread surface is made of 25mm steel plate.

6. The caisson sinking aid structure according to claim 1, characterized in that: The steel blade foot reinforcement ribs are made of 25mm steel plates and are evenly arranged at intervals of 800mm along the caisson wall.

7. The caisson sinking aid structure according to claim 1, characterized in that: The high-pressure water nozzles are rectangular with a height of 15 mm and a width of 75 mm, and are evenly arranged at intervals of 800 mm along the wall of the caisson.

8. A process for using the caisson sinking aid structure according to claim 1, characterized in that: a. Sinking wells in soft soil. Above the groundwater level, the water is drained and sunk. If the soil inside the caisson bulges, a soil plug is left in the caisson for ballast. At this time, the high-pressure water nozzle is started to lubricate the inner wall of the caisson, reducing or even eliminating the friction between the soil inside the caisson and the inner wall of the caisson. Below the groundwater, it sinks without drainage; b. Caisson in sandy soil layer, Above the groundwater level, the water is drained and the sand and soil under the steel blade foot are cleared. At this time, the lower part of the outer tube of the steel blade foot has been pressed into the sand and soil, preventing the sand and soil outside the caisson from entering the caisson, reducing the amount of soil taken for caisson construction, and reducing the risk of earthwork collapse outside the caisson. Below the groundwater, the caisson sinks without drainage. Start the high-pressure water nozzle, and the high-speed water flow carries the sand and soil out of the end of the steel blade foot tread, reducing the area of ​​the steel blade foot tread contacting the sand and soil, reducing the resistance of the blade foot tread, and making the caisson sink. At this time, the outer tube of the steel blade foot prevents the sand and soil outside the caisson from entering the caisson; c. When the caisson shows a sinking deviation, turn on the high-pressure water nozzle on the side with smaller settlement to reduce the contact area between the steel blade foot surface and the soil on this side, reduce the sinking resistance at this position, increase the sinking amount at this position, and achieve the purpose of correction.

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