Self-balancing few-support dumbbell-shaped combined pile body and construction method

Abstract

The invention discloses a self-balancing few-support dumbbell-shaped combined pile body and a construction method, and relates to the technical field of deep foundation pit cofferdam construction.The self-balancing few-support dumbbell-shaped combined pile body comprises an arc supporting frame and a lock catch fixing piece, and a plurality of steel pipes are arranged on the periphery of the arc supporting frame; the multiple steel pipes are arranged around the periphery of the arc supporting frame, so that a pouring cavity is defined by the multiple steel pipes; the lock catch fixing pieces are arranged on the two sides of the arc supporting frame, the lock catch fixing pieces abut against and position the arc supporting frame, the design that the arc supporting frame and the steel pipes define the pouring cavity is adopted, the lock catch fixing pieces abut against and position the arc supporting frame, and the stability and the self-balancing capacity of the whole structure are enhanced.

Description

Technical Field

[0001] The present application relates to the technical field of deep foundation pit cofferdam construction, and in particular to a self-balancing, less-supported dumbbell-shaped combined pile body and a construction method. Background Art

[0002] In the field of civil engineering, pile foundation is an important supporting structure for buildings and structures. Its stability and bearing capacity are directly related to the safety and reliability of the entire project. With the acceleration of urbanization and the continuous emergence of high-rise buildings, large bridges and other projects, the requirements for pile foundations are getting higher and higher. Although traditional pile foundation forms, such as single reinforced concrete piles, can meet engineering needs to a certain extent, their performance may be limited in complex geological conditions, high bearing requirements or special engineering environments.

[0003] Traditional pile structures often use a single material (such as reinforced concrete piles) and a simple shape (such as round or square). When subjected to complex loads, such piles may have problems such as insufficient anti-overturning capacity and great construction difficulty. Especially in scenarios with soft soil foundations or where multiple layers of soil with different properties need to be traversed, the applicability of traditional piles is limited.

[0004] Especially during the construction process, how to ensure the stability and positioning accuracy of the pile body, and how to improve the pouring quality and density of the pile concrete are key technical problems in the construction of combined piles. Traditional construction methods often cannot guarantee the overall performance and construction efficiency of the pile body, and are prone to problems such as large concrete void ratio and uneven pouring thickness.

[0005] Therefore, there is an urgent need for a dumbbell-shaped composite pile body and a construction method thereof with strong self-balancing ability, simple supporting structure, convenient construction and high concrete pouring quality to meet the high requirements of pile structure in modern civil engineering and construction fields. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a self-balancing less-supported dumbbell-shaped combined pile body and a construction method, wherein a self-balancing less-supported dumbbell-shaped combined pile body comprises:

[0007] An arc support frame, wherein a plurality of steel pipes are arranged on the periphery of the arc support frame, and the plurality of steel pipes are arranged around the periphery of the arc support frame so that the plurality of steel pipes enclose a casting cavity;

[0008] The locking fixing parts are arranged on both sides of the arc support frame, and the locking fixing parts abut against and position the arc support frame.

[0009] Optionally, in some embodiments of the present application, the arc support frame includes a first support member, and second support members are provided at both ends of the first support member. The first support member is rectangular, the second support member is circular, and the diameter of the second support member is greater than the width of the first support member.

[0010] Optionally, in some embodiments of the present application, a fixing groove is provided on the buckle fixing member corresponding to the position of the steel pipe. The steel pipe is located in the fixing groove, and the buckle fixing member is fixed on the steel casing through a guiding bracket.

[0011] Optionally, in some embodiments of the present application, the construction method includes:

[0012] Step 1: Design the diameter of the cofferdam according to the size of the bearing platform, prefabricate the buckle fixing member and the arc support frame according to the diameter of the cofferdam and assemble them, and install the steel pipe;

[0013] Step 2: Drive the steel pipe by a vibratory hammer, and control the error of the steel pipe driving within ≤10 mm;

[0014] Step 3: Pour concrete into the pouring cavity formed by the steel pipes, and check the void ratio of the concrete by ultrasonic testing;

[0015] Step 4: Pour the concrete in the pouring cavity in layers, and perform temperature detection and flatness detection on the concrete after final setting.

[0016] Optionally, in some embodiments of the present application, in Step 1:

[0017] The diameter of the cofferdam is measured by the safety margin of the cofferdam, and the design formula for the diameter of the cofferdam is D = W + 2×S safe ,

[0018] where D is the diameter of the cofferdam;

[0019] W is the actual width of the bearing platform;

[0020] S safe is the safety margin.

[0021] Optionally, in some embodiments of the present application, the safety margin S safe is measured by the parameters of the land, where:

[0022]

[0023] where H is the depth of foundation pit excavation (m);

[0024] q is the surface surcharge number (kPa);

[0025] γ is the unit weight value of soil (kN / m3 );

[0026] α and β are empirical coefficients.

[0027] Optionally, in some embodiments of the present application, in the third step, the concrete pouring process includes:

[0028] Step 301: Pour a layer of concrete at the bottom position of the pouring cavity, and measure the temperature of the concrete to form a concrete layer;

[0029] Step 302: Wait for the concrete layer to start setting. Spray and smear a slurry on the upper part of the set concrete layer to form a slurry layer, and then perform secondary pouring above the slurry layer, and measure the temperature of the concrete layer during the secondary pouring process;

[0030] Step 303: Monitor the temperature and strength of the overall concrete after multiple concrete layer pourings in real time.

[0031] Optionally, in some embodiments of the present application, in the step 302, the slurry includes a high-pressure spray slurry, the high-pressure spray slurry includes silica, graphene and polymer emulsion, and the spray pressure of the high-pressure spray slurry is 0.8 - 1.2 MPa, the coverage is 1.2 - 1.5 kg / m 2 , and the penetration depth is ≥5 mm.

[0032] Optionally, in some embodiments of the present application, in the step 302, surface roughening treatment is performed on the top position of the set concrete layer.

[0033] Optionally, in some embodiments of the present application, the roughening process includes:

[0034] Scan the flatness of the upper surface of the concrete layer by laser to generate flatness data. The roughening machine scrapes the concrete layer according to the flatness data, and synchronously adds a roughening agent to the top position of the concrete through the roughening machine.

[0035] Compared with the prior art, the beneficial effects in the present invention are:

[0036] 1. The combined pile body adopts the design of an arc support frame and multiple steel pipes surrounding a pouring cavity. The arc support frame is abutted and positioned by a locking fixing part, enhancing the stability and self-balancing ability of the overall structure. This design enables the pile body to distribute pressure more evenly when bearing loads, improving the bearing capacity and lateral displacement resistance of the pile body;

[0037] 2. The process of designing the diameter of the cofferdam according to the size of the bearing platform in the construction method, and the method of accurately inserting the steel pipe through the vibrating hammer ensure the convenience and accuracy of the construction process. The error of the steel pipe insertion is controlled within ≤10 mm, greatly improving the construction accuracy and ensuring the quality of the pile body. Description of the Drawings

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0039] Figure 1 It is a schematic diagram of the overall structure of the self-balanced less-supported dumbbell-shaped composite pile body provided by the embodiment of the present application;

[0040] Figure 2 It is a schematic diagram of the structure of the self-balanced less-supported dumbbell-shaped composite pile body from a top-down perspective provided by the embodiment of the present application;

[0041] Figure 3 It is a schematic diagram of the overall structure of the locking fastener cooperating with the steel casing provided by the embodiment of the present application;

[0042] Figure 4 It is a schematic diagram of the overall process of the construction method of the composite pile body provided by the embodiment of the present application.

[0043] Description of the Reference Numerals:

[0044] 100, arc support frame; 110, first support member; 120, second support member; 200, steel pipe; 210, pouring cavity; 300, locking fastener; 310, fixing groove; 320, guiding bracket; 400, steel casing. Detailed Embodiments

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of them. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present application. It can be understood that the drawings are only for reference and description, and are not used to limit the present application. The connection relationships shown in the drawings are only for clear description and do not limit the connection methods.

[0046] Specifically, as Figure 1As shown, in the embodiment of the present application, a self-balancing and less-supported dumbbell-shaped composite pile body is provided. The pile body as a whole presents a dumbbell structure. The pile body mainly includes an arc support frame 100. Among them, the arc support frame 100 is integrally arranged in a dumbbell shape. A plurality of steel pipes 200 are arranged at the outer periphery of the arc support frame 100. The plurality of steel pipes 200 are arranged side by side outside the arc support frame 100, so that the plurality of steel pipes 200 enclose a dumbbell-shaped structure. The area enclosed by the plurality of steel pipes 200 is a pouring cavity 210, and concrete is poured in the pouring cavity 210. At the same time, a plurality of steel casing tubes 400 are distributed in the pouring cavity 210.

[0047] On the basis of the above structure, a locking and fixing member 300 is also provided. In the present application, the locking and fixing member 300 is set as two fixing plates. As Figure 3 shown, the two fixing plates are respectively arranged on both sides of the arranged steel pipes 200. Fixing grooves 310 are opened at the positions corresponding to the steel pipes 200 on the two fixing plates. The shape of the fixing grooves 310 matches the shape of the steel pipes 200, so that when the two fixing plates are assembled together, the fixing grooves 310 fix the steel pipes 200 for positioning.

[0048] Among them, in the present application, the two fixing plates are connected by a lock to prevent the two fixing plates from being installed unstably. At the same time, in order to facilitate the fixing plates to position the steel pipes 200, a guiding bracket 320 is also arranged on the fixing plates. One end of the guiding bracket 320 far from the fixing plates is connected to the steel casing tube 400, which facilitates the fixing plates to position the steel pipes 200.

[0049] In the above, in order to facilitate the formation of the pile body with a dumbbell shape, more specifically, in the embodiment of the present application, the arc support frame 100 includes a first support member 110 and a second support member 120. As shown in the figure, the first support member 110 is arranged in a rectangular structure. Second support members 120 are respectively arranged on both sides of the first support member 110. The second support member 120 is arranged in a circular structure and is connected to the first support member 110. The diameter of the second support member 120 is greater than the width of the first support member 110, so as to form a dumbbell-shaped structure. This structure has certain advantages compared with other structures. The advantages include good structural stress, no need to set cross braces in the range of the pile cap tower column, and no need to change braces during the construction of the tower column.

[0050] Under the above structure, the present application also provides a construction method for the composite pile body. The construction method is mainly carried out by means of multi-layer pouring. More specifically:

[0051] First, it is necessary to design the diameter of the cofferdam according to the size of the pile cap. The cofferdam is used for pouring the dumbbell-shaped pile body. Among them, in order to facilitate the design of its size, it is necessary to calculate and measure according to the safety margin of the cofferdam. Among them, the measurement formula is:

[0052] D = W + 2×S safe

[0053] Among them, D is the diameter of the cofferdam (unit: m); W is the actual width of the pile cap (unit: m); S safe is the safety margin.

[0054] The safety margin is determined by the following formula:

[0055]

[0056] Among them, H is the excavation depth of the foundation pit (m);

[0057] q is the surface surcharge number (kPa);

[0058] γ is the unit weight value of soil (kN / m 3 );

[0059] α, β are empirical coefficients.

[0060] Among them, the value range of α is usually set between 0.1 - 0.2, and the value range of β is usually set between 0.05 - 0.1. The size of its value range is usually adjusted according to the soil type (clay, sand, etc.).

[0061] The surface surcharge q (kPa) mainly includes temporary loads such as construction machinery and piled loads, and the construction safety margin is judged according to the temporary loads.

[0062] Among them, in the embodiment of the present application, a specific calculation scheme is provided: when the pile cap width W = 20m; the excavation depth of the foundation pit H = 12m; the surface surcharge q = 15kPa (this number includes the construction machinery load); the unit weight of soil γ = 18kN / m 3 (silty clay); empirical coefficients: according to the soil quality, α = 0.15 (clay), β = 0.08 (short-term load).

[0063] According to the data detected by relevant equipment above, it can be obtained that:

[0064]

[0065] That is, the safety margin is 1.867m.

[0066] Calculate the diameter of the cofferdam according to the above safety margin:

[0067] D = 20 + 2×1.867 = 23.734m (rounded up to 24m)

[0068] Thus, the corresponding diameter of the cofferdam is obtained according to the site environment.

[0069] After completing the above calculation of the cofferdam size, locking fasteners 300 and arc supports are provided according to the diameter of the cofferdam, and the steel pipes 200 are assembled to facilitate the formation of a pouring cavity 210.

[0070] After completing the assembly of the pouring cavity 210, the steel pipes 200 are hammered vertically by a vibratory hammer to fix the steel pipes 200.

[0071] In the above, the vibrated and hammered steel pipes 200 are installed side by side, and the steel pipes 200 are limited by the fixing grooves 310 on the locking fasteners 300. Among them, the insertion error of the steel pipes 200 is controlled within ≤10 mm.

[0072] After completing the insertion of the steel pipes 200, concrete is poured into the formed pouring cavity 210. In the embodiment of the present application, the pouring of concrete is processed by a multi-layer pouring method. More specifically:

[0073] During the pouring process, the flatness of the bottom is checked by a laser scanner at the bottom position of the pouring cavity 210 to determine whether the bottom is inclined. When the bottom is flat, concrete is poured at the bottom to form the first layer of concrete at the bottom. Among them, after completing the first layer of concrete at the bottom, the void ratio of the concrete layer is checked by ultrasonic waves. In the embodiment of the present application, it is preferably controlled within the range of about 8% - 10%.

[0074] During the pouring of the first layer of concrete, the temperature of the concrete layer is also detected at the same time. Since the cofferdam structure in the present application is a dumbbell-shaped structure and the concrete pouring area is large, in order to better pour the concrete layer, in the embodiment of the present application, temperature sensors are provided in the area enclosed by the first support 110 and in the area enclosed by the second support 120. The temperature of the entire concrete layer is detected by the temperature sensors to avoid too large a temperature difference between the temperature in the first support 110 and the temperature in the second support 120. In the present application, when there is a large temperature difference, cold water pipes need to be provided to cool the local concrete so as to control the overall temperature difference within the range of about 5 degrees Celsius.

[0075] At the same time, in order to minimize the influence of the temperature difference on the concrete layer, in the present application, the thickness of the concrete layer is controlled within the range of about 70 cm - 80 cm.

[0076] After completing the first layer of concrete, it is necessary to wait for the top surface of the concrete layer to condense. After initial setting occurs, the position at the top of the concrete will be roughened. During the roughening process, a roughening machine is provided. Before the roughening machine roughens the concrete layer, it needs to scan the flatness of the concrete layer by laser to facilitate generating flatness data. The roughening machine scrapes the concrete layer according to this flatness data, and the roughening agent is added to the concrete synchronously during the scraping process. In the embodiment of the present application, the roughening composition is as follows:

[0077] The mass ratio of silicon carbide powder is 40%, and its function is to enhance the surface etching effect; the mass ratio of water-based epoxy resin is 25%, and its function is to improve the interfacial bonding strength; the mass ratio of nano-aluminum oxide is 10%, and its function is to reduce the friction coefficient; the mass ratio of the dispersant is 5%, and its function is to ensure the uniformity of the material.

[0078] After the roughening process is completed, the slurry will be sprayed and applied to the top position of the concrete layer. In the embodiment of the present application, the slurry is a mixture including silica, graphene, polymer emulsion and water, and the specific component ratios are as follows:

[0079] The nano-silica is set at a mass ratio of 45%, and this component can enhance the bonding strength; the graphene flakes are set at a mass ratio of 5%, and this component can enhance the crack resistance; the polymer emulsion is set at a mass ratio of 30%, and this component can improve the workability of construction; the remaining component is water, with a proportion of 20%, which is used to adjust the fluidity.

[0080] At this ratio, the slurry is sprayed on the top position of the concrete layer, and the spraying pressure is controlled at 0.8 - 1.2 MPa, the covering amount is 1.2 - 1.5 kg / m 2 、and the penetration depth is ≥5 mm. After the above spraying process is completed, a slurry layer is formed at the top position of the concrete layer.

[0081] After the spraying is completed, the concrete layer is poured again on the upper surface, and the pouring is cycled. At the same time, the temperature change and strength change of the concrete layer are also monitored in real time until the composite pile body is completed.

[0082] The above embodiments are only used to illustrate the technical method of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical method of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A self-balancing, less-supported dumbbell-shaped combined pile, characterized in that: include: An arc support frame, wherein a plurality of steel pipes are arranged on the periphery of the arc support frame, and the plurality of steel pipes are arranged around the periphery of the arc support frame so that the plurality of steel pipes enclose a casting cavity; The locking fixing parts are arranged on both sides of the arc support frame, and the locking fixing parts abut against and position the arc support frame.

2. A self-balancing, less-supported dumbbell-shaped combined pile according to claim 1, characterized in that: The arc support frame includes a first support member, and second support members are arranged at both ends of the first support member. The first support member is rectangular, and the second support member is circular. The diameter of the second support member is greater than the width of the first support member.

3. The self-balancing, less-supported dumbbell-shaped combined pile according to claim 1, characterized in that: A fixing groove is provided on the locking fixture at a position corresponding to the steel pipe, the steel pipe is located in the fixing groove, and the locking fixture is fixed to the steel casing through a guide corbel.

4. A construction method for manufacturing a self-balancing, less-supported dumbbell-shaped composite pile body as claimed in any one of claims 1 to 3, characterized in that: include: Step 1: Design the diameter of the cofferdam according to the size of the cap, prefabricate the locking fasteners and arc support frames according to the diameter of the cofferdam, assemble them, and install the steel pipes; Step 2: Use a vibrating hammer to punch the steel pipe, and the error of the steel pipe punching is controlled within ≤10mm; Step 3: pour concrete in the pouring cavity formed by the steel pipe, and check the porosity of the concrete by ultrasonic testing; Step 4: Pour the concrete in the pouring cavity in layers, and perform temperature and flatness tests on the concrete after final setting.

5. A construction method according to claim 4, characterized in that: In the step 1: The diameter of the cofferdam is measured by the safety margin of the cofferdam. The design formula of the diameter of the cofferdam is D = W + 2 × S safe , Where D is the diameter of the cofferdam; W is the actual width of the abutment; S safe For safety margin.

6. A construction method according to claim 5, characterized in that: The safety margin S safe The measurements are made using the parameters of the land, among which: Where, H is the excavation depth of the foundation pit (m); q is the surface overload number (kPa); γ is the soil weight (kN / m 3 ); α, β are empirical coefficients.

7. A construction method according to claim 4, characterized in that: In step 3, the pouring process of concrete includes: Step 301: pouring a layer of concrete at the bottom of the pouring cavity, and measuring the temperature of the concrete to form a concrete layer; Step 302: waiting for the concrete layer to initially set, spraying and applying slurry on the initial set concrete layer to form a slurry layer, performing secondary pouring on the slurry layer, and measuring the temperature of the concrete layer during the secondary pouring process; Step 303: Real-time monitoring of the temperature and strength of the entire concrete after multiple concrete layers are poured.

8. A construction method according to claim 7, characterized in that: In step 302, the slurry includes high-pressure spray slurry, the high-pressure spray slurry includes silicon dioxide, graphene and polymer emulsion, the spray pressure of the high-pressure spray slurry is 0.8-1.2MPa, and the coverage is 1.2-1.5kg / m 2 , penetration depth is ≥5mm.

9. A construction method according to claim 7, characterized in that: In step 302, a surface roughening treatment is performed on the top position of the concrete layer after initial setting.

10. A construction method according to claim 9, characterized in that: The roughening process comprises: The flatness of the upper surface of the concrete layer is measured by laser scanning to generate flatness data, and a roughening machine is used to scrape and coat the concrete layer according to the flatness data, and a roughening agent is simultaneously added to the top position of the concrete through the roughening machine.

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