A temperature control system for super-large diameter cast-in-place pile and its construction method

Abstract

The present invention relates to a temperature control system for a super-large diameter cast-in-place pile body and a construction method thereof, which comprises: a pile body, the pile body is fixed in seawater, and the outer surface of the pile body in the water section is painted with a heat-insulating coating; a steel pipe arranged along the longitudinal direction of the pile body, which is evenly arranged inside the pile body, and the steel pipe is filled with seawater for absorbing heat. The present invention relates to a temperature control system for a super-large diameter cast-in-place pile body and a construction method thereof, which adopts a method of dual control of internal and external temperatures, reduces the temperature difference between the inside and outside of the pile body, avoids excessive temperature stress, and ensures the pile quality of the super-large diameter cast-in-place pile.

Description

Technical Field

[0001] The invention relates to the technical field of deepwater foundation construction, and in particular to a temperature control system for a super-large diameter cast-in-place pile body and a construction method thereof. Background Art

[0002] In recent years, the construction of large-scale offshore projects such as cross-sea bridges has gradually increased and has been pushed into the deep sea. The deep-water foundation of marine engineering needs to withstand huge horizontal forces, including the crosswind load of the upper structure, wave force, ship collision force and earthquake force, etc. In order to meet the horizontal bearing capacity and horizontal stiffness requirements of the deep-water foundation, bored piles need to adopt super-large diameter pile foundations. At present, the largest single pile diameter of bored piles in China reaches 6.8m, which is a large-volume concrete structure.

[0003] In the related technology, during the pouring of concrete for the bored pile body, due to the influence of hydration heat, the interior of the pile body is in an adiabatic state and cannot dissipate heat. The surface of the pile body is in direct contact with seawater and is in a condition of infinite heat dissipation, resulting in a large temperature difference between the inside and outside, excessive temperature stress, and the pile body is prone to cracking, making it difficult to ensure the quality of the pile.

[0004] Therefore, it is necessary to design a temperature control system for super-large diameter cast-in-place piles to overcome the above problems. Summary of the invention

[0005] The embodiment of the present invention provides a temperature control system for an ultra-large diameter cast-in-place pile body and a construction method thereof, so as to solve the problem in the related art that during the pouring of pile body concrete, the temperature difference between the inside and outside of the pile body is large, resulting in excessive temperature stress and making the pile body easy to crack.

[0006] In a first aspect, a temperature control system for an extra-large diameter cast-in-place pile body is provided, comprising: a pile body, the pile body being fixed in seawater, and the outer surface of the pile body located in the water being coated with a thermal insulation coating; a steel pipe arranged along the longitudinal direction of the pile body, which is evenly distributed inside the pile body, and the steel pipe is filled with seawater for absorbing heat.

[0007] In some embodiments, the thermal insulation coating is a highly water-resistant composite thermal insulation coating, and a modifier is added to the thermal insulation coating to enhance its corrosion resistance and resistance to high water pressure.

[0008] In some embodiments, the bottom of the pile body is located below the surface of the seabed, the steel pipe is located above the surface of the seabed, the bottom surface of the steel pipe is higher than the surface of the seabed, and the bottom of the steel pipe is sealed.

[0009] In some embodiments, the pile body includes a steel casing and a steel cage located inside the steel casing; the steel pipe is located near the center of the steel casing and is fixed to the steel cage via support rods.

[0010] In some embodiments, the steel pipe includes: a first steel pipe located at the center of the steel casing; and a second steel pipe surrounding the first steel pipe, the second steel pipe is spaced apart from the first steel pipe, and the first steel pipe and the second steel pipe are both fixed to the steel cage.

[0011] In some embodiments, the bottom of the first steel tube is connected to the second steel tube.

[0012] In some embodiments, temperature sensors are installed on the outer surface of the steel casing, the outer surface of the thermal insulation coating, and the outer surface of the steel pipe.

[0013] In a second aspect, a construction method for the temperature control system of the above-mentioned super-large diameter cast-in-place pile body is provided, comprising the following steps: providing a steel casing of a preset diameter, and applying the thermal insulation coating on the outside of the steel casing; lowering the steel casing coated with the thermal insulation coating to a preset position in the seawater, and lowering a steel cage into the steel casing accordingly; lowering the steel pipe into the steel casing, and fixing the steel pipe and the steel cage, and at the same time, pouring seawater into the steel pipe; pouring concrete in the steel casing to form the pile body.

[0014] In some embodiments, providing a steel casing of a preset diameter and applying the thermal insulation coating on the outside of the steel casing comprises the following steps: hoisting the steel casing, evenly applying the thermal insulation coating on the outer surface of the steel casing, and reserving a welding area at the end of the steel casing; after the thermal insulation coating on the surface of the steel casing is dried, hoisting the steel casing down to the placement area.

[0015] In some embodiments, the steel casing includes multiple sections, and the end of the steel casing has a welding area. The steel casing coated with the thermal insulation coating is lowered to a preset position in the seawater, and the steel cage is lowered into the steel casing accordingly, comprising the following steps: hoisting at least two sections of steel casing coated with the thermal insulation coating to a preset position in the seawater, and exposing the welding area of ​​the steel casing to the air, and after the welding areas of two adjacent sections of the steel casing are welded and fixed to each other, the thermal insulation coating is applied to the welding position.

[0016] The beneficial effects brought about by the technical solution provided by the present invention include:

[0017] The embodiment of the present invention provides a temperature control system for a super-large diameter bored pile body and a construction method thereof. Since a thermal insulation coating is applied to the outer surface of the pile body, the condition of the super-large diameter bored pile body in the water section being in infinite heat dissipation is changed, the heat dissipation rate of the pile body surface is reduced, and the temperature can be reduced synchronously with the inside of the pile body. At the same time, a steel pipe is arranged inside the pile body, and the steel pipe is filled with seawater that can absorb heat, so that the inside of the pile body can be dissipated, thereby having the effect of reducing the temperature inside the pile body. Therefore, a method of dual control of internal and external temperatures is adopted to reduce the temperature difference between the inside and outside of the pile body, avoid excessive temperature stress, and ensure the pile quality of the super-large diameter bored pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic diagram of a temperature control system for a super-large diameter cast-in-place pile provided by an embodiment of the present invention;

[0020] Figure 2 A schematic top view of a pile body of an ultra-large diameter cast-in-place pile body temperature control system provided by an embodiment of the present invention;

[0021] Figure 3 A schematic front view of another temperature control system for a super-large diameter cast-in-place pile provided by an embodiment of the present invention;

[0022] Figure 4 A schematic top view of another temperature control system for a super-large diameter cast-in-place pile provided in an embodiment of the present invention is provided.

[0023] In the figure:

[0024] 1. Pile body; 11. Steel casing;

[0025] 2. Thermal insulation coating;

[0026] 3. Steel pipe; 31. First steel pipe; 32. Second steel pipe;

[0027] 4. Temperature sensor. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The embodiment of the present invention provides a temperature control system for an ultra-large diameter cast-in-place pile body and a construction method thereof, which can solve the problem in the related art that during the pouring of pile body concrete, the temperature difference between the inside and outside of the pile body is large, resulting in excessive temperature stress and making the pile body easy to crack.

[0030] See also Figure 1 and Figure 3 As shown, an embodiment of the present invention provides a temperature control system for a super-large diameter cast-in-place pile body, which may include: a pile body 1, which may be fixed in seawater, and the pile body 1 may include a steel casing 11 and concrete poured inside the steel casing 11, and the outer surface of the steel casing 11 located in the water section (that is, the part of the steel casing 11 exposed to the seawater) may be coated with a thermal insulation coating 2, and the thermal insulation coating 2 isolates the steel casing 11 from the seawater, and the thermal insulation coating 2 has a small thermal conductivity and a large thermal resistance, which can prevent the seawater from taking away the heat from the surface of the steel casing 11, thereby changing the condition that the pile body 1 in the water section of the cast-in-place pile is in an infinite heat dissipation state, and playing a role in the cast-in-place pile water The middle section of the pile body 1 has the function of heat preservation, which reduces the heat dissipation rate on the surface of the pile body 1; and the steel pipe 3 arranged along the longitudinal direction of the pile body 1, the steel pipe 3 can be evenly arranged in the steel casing 11, and the steel pipe 3 can be filled with seawater for absorbing heat. When the concrete is poured in the steel casing 11 and hydration heat occurs, the seawater in the steel pipe 3 can absorb a large amount of heat inside the steel casing 11, thereby achieving the effect of lowering the internal temperature, changing the internal state of the super-large diameter bored pile to be in an adiabatic state, and can be cooled synchronously with the surface of the pile body 1; in this embodiment, the diameter of the steel casing 11 is 6.8m, and a steel pipe 3 with a diameter of 1m is installed in the center of the steel casing 11.

[0031] See also Figure 1 and Figure 2 As shown, in some embodiments, the thermal insulation coating 2 can be a highly water-resistant composite thermal insulation coating 2, which has strong waterproof properties, small thermal conductivity, large thermal resistance, light weight, and no pollution to the environment. Modifiers for enhancing its corrosion resistance and high water pressure resistance can be added to the thermal insulation coating 2, so that the thermal insulation coating 2 has better acid resistance, alkali resistance, and water pressure resistance, can be used in seawater for a long time, and is very suitable for marine engineering.

[0032] See also Figure 1 and Figure 3As shown, in some optional embodiments, the bottom of the pile body 1 can be buried below the seabed surface, the steel pipe 3 is located above the seabed surface, and the bottom surface of the steel pipe 3 can be higher than the seabed surface, so that the bottom end of the steel pipe 3 is separated from the seabed surface by a distance. In this embodiment, the bottom end of the steel pipe 3 is 50 cm away from the seabed surface, the top end of the steel pipe 3 is flush with the top end of the steel casing 11, and the top end of the steel pipe 3 can be submerged in seawater. Since the temperature difference between the inside and outside of the pile body 1 located below the seabed surface is small when pouring concrete, the temperature difference between the inside and outside of the pile body 1 located above and close to the seabed surface will not be particularly large. When the height of the pile body 1 is the same, the bottom end of the steel pipe 3 is separated from the seabed surface by a distance, which can shorten the length of the steel pipe 3 and will not have a significant impact on the quality of the pile body 1, thereby reducing costs and achieving high economic benefits; and the bottom of the steel pipe 3 can be blocked to prevent concrete from entering the steel pipe 3 when pouring concrete.

[0033] See also Figure 1 and Figure 2 As shown, in some embodiments, a steel cage may be provided in the steel casing 11, and the steel cage may enhance the strength of the pile body 1 as a whole; the steel pipe 3 may be located near the center of the steel casing 11. Since the temperature near the center of the steel casing 11 is the highest when hydration heat occurs, the steel pipe 3 is located near the center of the steel casing 11, so that the seawater in the steel pipe 3 can greatly reduce the temperature around the center of the steel casing 11, and greatly reduce the temperature difference between the inside and outside of the steel casing 11. The steel pipe 3 may be fixed to the steel cage by a support rod to avoid tilting of the steel pipe 3 when pouring concrete, and at the same time, the strength of the pile body 1 may be enhanced.

[0034] See also Figure 1 As shown, in some optional embodiments, the side wall of the steel casing 11 can be provided with a small hole, the bottom of the steel pipe 3 can be bent horizontally and pass through the small hole on the side wall of the steel casing 11 to reach the outside of the steel casing 11, so that the bottom end of the steel pipe 3 can be immersed in seawater. At the same time, an electric switch can be installed at the bottom end of the steel pipe 3. When the temperature in the steel pipe 3 is too high, the electric switch can be controlled to open the bottom end of the steel pipe 3, the hot water in the steel pipe 3 flows up, and the cold seawater enters the steel pipe 3 from the bottom end of the steel pipe 3, thereby achieving quick and convenient cooling.

[0035] See also Figure 1 As shown, preferably, a filter screen can be added at the bottom of the steel pipe 3 to prevent foreign matter such as mud and sand on the seabed from entering the steel pipe 3 and clogging the steel pipe 3.

[0036] See also Figure 3 and Figure 4As shown, in some embodiments, the steel pipe 3 may include: a first steel pipe 31 located at the center of the steel casing 11; and a plurality of second steel pipes 32 surrounding the first steel pipe 31. The second steel pipes 32 may be spaced apart from the first steel pipe 31, so that the first steel pipe 31 may reduce the temperature at the center of the pile body 1, and the second steel pipes 32 distributed between the first steel pipe 31 and the steel casing 11 may evenly reduce the temperature at other positions of the pile body 1, so that the temperature at the center of the pile body 1 and the temperature between the center and the outer wall may be roughly evenly distributed, with a small temperature difference. The first steel pipe 31 and the second steel pipe 32 may be fixed to the steel cage by support rods, or the first steel pipe 31 and the second steel pipe 32 may be fixed to the steel cage by support rods. The two steel pipes 32 are directly welded and fixed to the steel cage, and the added first steel pipe 31 and second steel pipe 32 can further enhance the strength inside the pile body 1; in this embodiment, there are 4 second steel pipes 32, and the diameters of the first steel pipe 31 and the second steel pipe 32 are the same, both of which are 0.5m, and the second steel pipe 32 is preferably arranged at a position half the radius of the steel casing 11 along the radial direction of the steel casing 11, that is, the distance between the second steel pipe 32 and the first steel pipe 31 is equal to half the radius of the steel casing 11, so that the first steel pipe 31 and the second steel pipe 32 are evenly distributed in the steel casing 11, avoiding excessive temperature reduction at the center of the pile body 1 or near the inner wall of the steel casing 11.

[0037] See also Figure 3 and Figure 4 As shown, in some optional embodiments, the bottom of the first steel pipe 31 can be connected to the second steel pipe 32, so that the heat in the first steel pipe 31 can be exchanged with the heat in the second steel pipe 32. When the temperature in the first steel pipe 31 is greater than the temperature in the second steel pipe 32, the cold water in the second steel pipe 32 can enter the first steel pipe 31 to reduce the temperature in the first steel pipe 31. When the temperature in the second steel pipe 32 is greater than the temperature in the first steel pipe 31, the cold water in the first steel pipe 31 can enter the second steel pipe 32 to reduce the temperature in the second steel pipe 32, thereby achieving that after the internal temperature of the steel casing 11 is reduced, the temperature difference between various parts inside is small, and the temperature in the pile body 1 is uniform.

[0038] See also Figure 1 and Figure 3 As shown, on the basis of the above technical solution, the outer surface of the steel casing 11, the outer surface of the thermal insulation coating 2, and the outer surface of the steel pipe 3 can be installed with temperature sensors 4. The sensor installed on the steel pipe 3 can measure the temperature of the outer wall of the steel pipe 3. When the temperature on the steel pipe 3 exceeds the preset value, the electric switch at the bottom of the steel pipe 3 can be controlled to open; the temperature sensor 4 installed on the outer surface of the steel casing 11 and the outer surface of the thermal insulation coating 2 can measure the temperature inside and outside the thermal insulation coating 2, and monitor the thermal insulation condition of the thermal insulation coating 2; at the same time, the temperature sensor 4 can also be installed on the inner surface of the steel casing 11, and the temperature inside and outside the steel casing 11 can be measured and compared to control the temperature difference inside and outside the steel casing 11.

[0039] The embodiment of the present invention further provides a construction method of the above-mentioned super-large diameter cast-in-place pile body temperature control system, comprising the following steps:

[0040] Step 1: Provide a steel casing 11 of a preset diameter, and apply a thermal insulation coating 2 on the outside of the steel casing 11.

[0041] In some embodiments, before step 1, the bottom elevation and top elevation of the bored pile in the water section can be calculated based on the construction data, and the steel casing 11 corresponding to the bored pile in the water section can be marked, and the steel casing 11 can be cleaned to ensure that there is no dust, mud, oil stains, etc., so as to apply the strong water-resistant composite thermal insulation coating 2.

[0042] In some optional embodiments, in step 1, providing a steel casing 11 of a preset diameter and applying a thermal insulation coating 2 to the outside of the steel casing 11 can specifically include: lifting the steel casing 11 horizontally with a crane, having workers evenly apply a strong water-resistant composite thermal insulation coating 2 to its outer surface, and reserving a welding area at the end of the steel casing 11, and not painting the welding area first; after the paint on the surface of the steel casing 11 is dried, the steel casing 11 is lowered and placed in the placement area, and all the steel casing 11 sections that need to be placed in the seawater are painted in turn by this operation.

[0043] Step 2: lower the steel casing 11 coated with the thermal insulation coating 2 to a preset position in the seawater, and lower the steel cage into the steel casing 11 accordingly.

[0044] In some embodiments, in step 2, the steel casing 11 coated with the thermal insulation coating 2 is lowered to a preset position in the seawater, and the steel cage is lowered into the steel casing 11 accordingly. Specifically, the following steps may be included: during the lowering process of the steel casing 11, a section of the steel casing 11 coated with the thermal insulation coating 2 is first hoisted to a preset position in the seawater, and the welding area at the top is exposed to the air (that is, exposed to the seawater surface), and the next section of the steel casing 11 is hoisted to the top of the previous section of the steel casing 11. After the welding areas of the two steel casings 11 are welded and fixed to each other, the thermal insulation paint 2 is applied to the welding places to ensure that the coating is complete. After the paint is dried, the two steel casings 11 are moved down, and then another steel casing 11 is hoisted in the same way until all the steel casings 11 are assembled. The bottom steel casing 11 is firmly buried in the preset position below the seabed surface; then the steel cage is lowered accordingly and installed in the steel casing 11.

[0045] Step 3: lower the steel pipe 3 into the steel casing 11 and fix the steel pipe 3 to the steel cage. At the same time, fill the steel pipe 3 with seawater.

[0046] In some embodiments, in step 3, after the steel casing 11 and the steel cage are lowered and installed, the steel pipe 3 is lowered to the corresponding position inside the steel casing 11, and the steel pipe 3 and the steel cage are fixed by support rods so that the top of the steel pipe 3 is flush with the top of the steel casing 11. At the same time, the top of the steel pipe 3 is submerged in seawater so that the interior of the steel pipe 3 is filled with seawater.

[0047] Step 4: pouring concrete in the steel casing 11 to form the pile body 1.

[0048] The construction condition is winter construction (12°C mold temperature and 10°C water temperature), the steel pipe 3 filled with seawater is not set inside the pile body 1, and the outer surface of the pile body 1 is not painted with thermal insulation paint 2, which is set as working condition one; the construction condition is summer construction (28°C mold temperature and 20°C water temperature), the steel pipe 3 filled with seawater is not set inside the pile body 1, and the outer surface of the pile body 1 is not painted with thermal insulation paint 2, which is set as working condition two; the construction condition is winter construction (12°C mold temperature and 10°C water temperature), the steel pipe 3 with a diameter of 1m and filled with seawater is set inside the pile body 1, and the outer surface of the pile body 1 is not painted with thermal insulation paint 2, which is set as working condition three; the construction condition is summer construction (28°C mold temperature and 20°C water temperature), the steel pipe 3 with a diameter of 1m and filled with seawater is set inside the pile body 1, and the outer surface of the pile body 1 is not painted with thermal insulation paint 2, which is set as working condition four; the construction condition is winter construction The construction condition is summer construction (12°C mold temperature and 10°C water temperature), the steel pipe 3 filled with seawater is not set inside the pile body 1, and the outer surface of the pile body 1 is painted with thermal insulation coating 2, which is set as working condition five; the construction condition is summer construction (28°C mold temperature and 20°C water temperature), the steel pipe 3 filled with seawater is not set inside the pile body 1, and the outer surface of the pile body 1 is painted with thermal insulation coating 2, which is set as working condition six; the construction condition is winter construction (12°C mold temperature and 10°C water temperature), the steel pipe 3 with a diameter of 1m and filled with seawater is set inside the pile body 1, and the outer surface of the pile body 1 is painted with thermal insulation coating 2, which is set as working condition seven; the construction condition is summer construction (28°C mold temperature and 20°C water temperature), the steel pipe 3 with a diameter of 1m and filled with seawater is set inside the pile body 1, and the outer surface of the pile body 1 is painted with thermal insulation coating 2, which is set as working condition eight, and the temperature calculation results and stress calculation results are as follows:

[0049] (1) Temperature calculation results are shown in Table 1:

[0050] Table 1 Temperature calculation results

[0051]

[0052] When the construction conditions are all winter construction (the mold temperature is 12°C), the theoretical temperature peak of the pile body 1 in working condition 1 is 53.2°C, and the peak temperature of the pile body 1 in working condition 3 is 49.8°C. The theoretical temperature peak of working condition 3 is about 6.8% lower than that of working condition 1.

[0053] When the construction conditions are summer construction (molding temperature is 28°C), the theoretical temperature peak of pile body 1 in working condition 2 is 69.1°C, and the peak temperature of pile body 1 in working condition 4 is 65.4°C. The theoretical temperature peak of working condition 4 is about 5.7% lower than that of working condition 2.

[0054] From the above, it can be seen that the arrangement of the steel pipe 3 with a diameter of 1 m to pass water inside the pile body 1 plays a certain role in reducing the temperature peak; in addition, the temperature peak of the pile body 1 without the steel pipe 3 appears around 120h, while the temperature peak of the pile body 1 with the steel pipe 3 appears earlier, around 72h, indicating that the water passing inside the pile body 1 plays a beneficial role in releasing the hydration heat inside the concrete.

[0055] The maximum temperature difference between the inside and outside of the pile body 1 in working condition 1 is 43.2°C. When the side of the pile body 1 is coated with thermal insulation coating 2, the maximum temperature difference between the inside and outside of the pile body 1 in working condition 5 is 18.8°C. The maximum temperature difference in working condition 5 is reduced by about 56.5% compared with working condition 1.

[0056] The maximum inside-outside temperature difference of the pile body 1 in working condition 2 is 49.1°C. When the side of the pile body 1 is coated with thermal insulation coating 2, the maximum inside-outside temperature difference of the pile body 1 in working condition 6 is 20.2°C. The maximum inside-outside temperature difference in working condition 6 is reduced by about 58.9% compared with that in working condition 2.

[0057] The maximum inside-outside temperature difference of the pile body 1 in working condition three is 39.8°C. When the side of the pile body 1 is coated with thermal insulation coating 2, the maximum inside-outside temperature difference of the pile body 1 in working condition seven is 17.5°C. The maximum inside-outside temperature difference in working condition seven is reduced by about 56.0% compared with that in working condition three.

[0058] The maximum inside-outside temperature difference of the pile body 1 in working condition 4 is 45.4°C. When the side of the pile body 1 is coated with thermal insulation coating 2, the maximum inside-outside temperature difference of the pile body 1 in working condition 8 is 19.5°C. The maximum inside-outside temperature difference in working condition 8 is reduced by about 57.0% compared with working condition 4.

[0059] From the above, it can be seen that coating the side of the pile body 1 with the thermal insulation coating 2 plays a very significant role in reducing the temperature difference between the inside and the outside. This is mainly because without the thermal insulation coating 2, the side of the pile body 1 cannot store heat, and the side temperature is the sea water temperature. After coating with the thermal insulation coating 2, the heat storage effect is more significant, which is effective in reducing the temperature difference between the inside and the outside and reducing temperature stress.

[0060] (2) Stress calculation results are shown in Table 2:

[0061] Table 2 Stress calculation results

[0062]

[0063]

[0064] During the temperature change of concrete, the overall change law of stress is: in the heating stage, before and after the temperature peak is reached inside the concrete, the surface tensile stress is large; in the cooling stage, the internal compressive stress gradually changes to tensile stress.

[0065] When the construction conditions are winter construction (molding temperature is 12°C), the maximum principal tensile stress of the pile body 1 in working condition 1 is 3.50Mpa, and the maximum principal tensile stress of the pile body 1 in working condition 3 is 3.16Mpa. The maximum principal tensile stress of working condition 3 is about 12.0% lower than that of working condition 1.

[0066] When the construction conditions are summer construction (molding temperature is 28℃), the maximum principal tensile stress of pile body 1 in working condition 2 is 3.73Mpa, and the maximum principal tensile stress of pile body 1 in working condition 4 is 3.29Mpa. The maximum principal tensile stress in working condition 4 is about 13.4% lower than that in working condition 2.

[0067] From the above, it can be seen that the arrangement of the steel pipe 3 with a diameter of 1 m inside the pile body 1 and the passage of water therethrough plays a certain role in reducing the maximum principal tensile stress.

[0068] The maximum principal tensile stress of the pile body 1 in working condition 1 is 3.54 MPa. When the side of the pile body 1 is coated with thermal insulation coating 2, the maximum principal tensile stress of the pile body 1 in working condition 5 is 3.19 MPa. The maximum principal tensile stress in working condition 5 is reduced by about 9.89% compared with working condition 1.

[0069] The maximum principal tensile stress of the pile body 1 in working condition 2 is 3.73 MPa. When the side of the pile body 1 is coated with thermal insulation coating 2, the maximum principal tensile stress of the pile body 1 in working condition 6 is 3.32 MPa. The maximum principal tensile stress in working condition 6 is reduced by about 11.0% compared with that in working condition 2.

[0070] The maximum principal tensile stress of the pile body 1 in working condition three is 3.16 MPa. When the side of the pile body 1 is coated with thermal insulation coating 2, the maximum principal tensile stress of the pile body 1 in working condition seven is 2.91 MPa. The maximum principal tensile stress in working condition seven is reduced by about 7.9% compared with that in working condition three.

[0071] The maximum principal tensile stress of the pile body 1 in working condition 4 is 3.29 MPa. When the side of the pile body 1 is coated with thermal insulation coating 2, the maximum principal tensile stress of the pile body 1 in working condition 8 is 3.06 MPa. The maximum principal tensile stress in working condition 8 is reduced by about 7.0% compared with that in working condition 4.

[0072] From the above, it can be seen that coating the side of the pile body 1 with the thermal insulation coating 2 plays a certain role in reducing the maximum principal tensile stress, mainly because it can reduce the temperature difference between the inside and the outside, and has a more obvious effect on controlling temperature stress.

[0073] The principles of a temperature control system for a super-large diameter cast-in-place pile and a construction method thereof provided by an embodiment of the present invention are as follows:

[0074] Since the outer surface of the pile body 1 is coated with a thermal insulation coating 2, the thermal insulation coating 2 has a small thermal conductivity, a large thermal resistance, is lightweight, and does not pollute the environment. The steel casing 11 is isolated from the seawater, which can prevent the seawater from taking away the heat from the surface of the steel casing 11, changing the condition of the pile body 1 of the super-large diameter cast-in-place pile in the water section to be in infinite heat dissipation, reducing the heat dissipation rate on the surface of the pile body 1, and can be cooled synchronously with the inside of the pile body 1. At the same time, a steel pipe 3 is arranged inside the pile body 1, and the steel pipe 3 is filled with seawater that can absorb heat. When hydration heat occurs during pouring concrete, the seawater can dissipate heat from the inside of the pile body 1, thereby reducing the internal temperature of the pile body 1. Therefore, the method of dual control of internal and external temperatures is adopted to reduce the temperature difference between the inside and outside of the pile body 1, avoid excessive temperature stress, and ensure the pile quality of the super-large diameter cast-in-place pile.

[0075] In the description of the present invention, it should be noted that the terms "upper", "lower", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0076] It should be noted that, in the present invention, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0077] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A temperature control system for a super-large diameter cast-in-place pile, characterized in that: It includes: A pile body (1), the pile body (1) being fixed in seawater, and the outer surface of the pile body (1) located in the water is coated with a thermal insulation coating (2); The steel pipe (3) is arranged along the longitudinal direction of the pile body (1), is evenly distributed inside the pile body (1), and is filled with seawater for absorbing heat; The pile body (1) comprises a steel casing (11) and a steel cage located inside the steel casing (11); The steel pipe (3) is located near the center of the steel casing (11) and is fixed to the steel cage via support rods; The steel pipe (3) comprises: A first steel pipe (31) located at the center of the steel casing (11); and a second steel pipe (32) surrounding the first steel pipe (31), the second steel pipe (32) being arranged at an interval from the first steel pipe (31), and the first steel pipe (31) and the second steel pipe (32) being both fixed to the steel cage; Temperature sensors (4) are installed on the outer surface of the steel casing (11), the outer surface of the thermal insulation coating (2), and the outer surface of the steel pipe (3).

2. The temperature control system for the super-large diameter cast-in-place pile body according to claim 1, characterized in that: The thermal insulation coating (2) is a highly water-resistant composite thermal insulation coating (2), and a modifier for enhancing the corrosion resistance and high water pressure resistance of the thermal insulation coating (2) is added to the thermal insulation coating (2).

3. The temperature control system for the super-large diameter cast-in-place pile body according to claim 1, characterized in that: The bottom of the pile body (1) is located below the seabed surface, the steel pipe (3) is located above the seabed surface, the bottom surface of the steel pipe (3) is higher than the seabed surface, and the bottom of the steel pipe (3) is sealed.

4. The temperature control system for the super-large diameter cast-in-place pile body according to claim 1, characterized in that: The bottom of the first steel pipe (31) is connected to the second steel pipe (32).

5. A construction method for a temperature control system for a super-large diameter cast-in-place pile as claimed in claim 1, characterized in that: The following steps are involved: Providing a steel casing (11) of a preset diameter, and applying the thermal insulation coating (2) to the outside of the steel casing (11); Lowering the steel casing (11) coated with the thermal insulation coating (2) to a preset position in the seawater, and correspondingly lowering the steel cage into the steel casing (11); Lowering the steel pipe (3) into the steel casing (11), fixing the steel pipe (3) to the steel cage, and at the same time, pouring seawater into the steel pipe (3); Concrete is poured into the steel casing (11) to form the pile body (1).

6. The construction method according to claim 5, characterized in that: The method of providing a steel casing (11) of a preset diameter and applying the thermal insulation coating (2) on the outside of the steel casing (11) comprises the following steps: Lifting the steel casing (11), evenly applying the thermal insulation coating (2) to the outer surface of the steel casing (11), and reserving a welding area at the end of the steel casing (11); After the thermal insulation coating (2) on the surface of the steel casing (11) is dried, the steel casing (11) is hung down to the placement area.

7. The construction method according to claim 6, characterized in that: The steel casing (11) comprises a plurality of sections, and the end of the steel casing (11) has a welding area. The steel casing (11) coated with the thermal insulation coating (2) is lowered to a preset position in the seawater, and the steel cage is correspondingly lowered into the steel casing (11), comprising the following steps: At least two sections of steel casing (11) coated with the thermal insulation coating (2) are hoisted to a preset position in the seawater, and the welding areas of the steel casing (11) are exposed to the air. After the welding areas of two adjacent sections of the steel casing (11) are welded and fixed to each other, the thermal insulation coating (2) is re-coated at the welding locations.

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