Temperature measuring method for mass concrete of underground diaphragm wall support

Abstract

The invention discloses an underground diaphragm wall support mass concrete temperature measurement method, which comprises the following steps of S1, selecting an underground diaphragm wall monitoring sample, and designing a temperature measurement guide pipe and a temperature measurement condensation pipe; s2, arranging temperature measurement points; s3, a temperature measurement guide pipe, a temperature measurement condensation pipe and a temperature measurement wire are installed; s4, pouring concrete, and measuring the temperature of the mass concrete to obtain temperature data; and S5, analyzing the temperature data, and judging the influence of the temperature difference between the inner surface and the outer surface of the permanent support mass concrete on the concrete crack based on an analysis result. According to the method, concrete temperature measurement and data accuracy can be ensured, meanwhile, supporting data are provided for temperature difference control of permanent supporting mass concrete so as to reduce the influence of concrete cracks, and experience is accumulated for judgment of curing time, adjustment of construction progress, arrangement of pouring sequence and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measurement for diaphragm wall support, and particularly to a temperature measurement method and system for mass concrete of diaphragm wall support. Background Technique

[0002] With the acceleration of the urbanization process, the construction of infrastructure such as high-rise buildings and large underground projects has developed vigorously. The diaphragm wall, as an effective form of deep foundation pit support and underground structure exterior wall, is widely used. During the construction of the diaphragm wall, the pouring of mass concrete is a key link. At present, the influence of temperature on the durability of underwater concrete in the form of permanent support and the concrete wrapped by soil in construction projects is temporarily blank. Therefore, it is of crucial significance to monitor its temperature.

[0003] Due to the large structural size of mass concrete, a large amount of heat accumulates inside the concrete and is difficult to dissipate quickly during the process of cement hydration heat release. The cement hydration reaction is usually the most intense in the early stage after pouring, generating a large amount of heat, which causes the internal temperature of the concrete to rise sharply. Taking common C30 concrete as an example, the peak value of its cement hydration heat generally appears 2 - 3 days after pouring, and the internal temperature can be 30℃ - 50℃ higher than the pouring temperature. Also, due to the particularity of the diaphragm wall, both sides are soil layers, and the internal temperature is difficult to be released, resulting in a large temperature difference between the inside and the outside. This significant contrast between the internal high temperature and the surrounding soil temperature causes a large temperature gradient between the inside and the surface of the concrete. And an excessive temperature gradient will cause non-uniform deformation of the concrete, and then generate temperature stress. When the temperature stress exceeds the tensile strength of the concrete, it will cause the concrete to crack. The appearance of cracks not only affects the appearance quality of the diaphragm wall, but also seriously weakens its bearing capacity, waterproof performance and durability, bringing huge potential safety hazards to the project.

[0004] The conventional temperature measurement method for the foundation slab needs to be installed after the steel bars are tied and before the concrete is poured. The temperature measurement wire needs to be tied to a steel bar, and its temperature sensing part should be at the temperature measurement point. When tying, it should be ensured that the temperature measurement wire does not directly contact the steel bar. However, this temperature measurement method will bring the following problems to the temperature measurement of the diaphragm wall: I. During the pouring process, it is very difficult to ensure that the temperature measuring wires do not come into contact with the steel bars. This often leads to inaccurate temperature measurement data after pouring, unable to reflect the true temperature inside the concrete, causing significant misunderstandings in construction management. II. When the temperature measuring wires are tied to the steel bars, and the steel bars are fixed on the wall and column steel bars, the steel bars are prone to displacement during the pouring process, and even the temperature measuring wires may break, resulting in inaccurate temperature measurement data and unable to measure actually. III. During the hoisting process of the diaphragm wall steel cage, it is easy to damage the temperature measuring wires, resulting in inability to measure data later. IV. The temperature measuring wires embedded during the temperature measurement of mass concrete cannot be recycled, resulting in relatively high cost. V. Traditional temperature measurement methods only focus on temperature measurement. If the temperature difference between the inside and the surface is large, only conventional methods such as covering with insulation can be adopted, but this method is not applicable to diaphragm walls. Summary of the Invention

[0005] The purpose of the present invention is to provide a temperature measurement method and system for mass concrete supported by diaphragm walls to solve the problems raised in the above background technology.

[0006] To achieve the above purpose, the present invention provides a temperature measurement method for mass concrete supported by diaphragm walls, including the following steps: S1. Select a diaphragm wall monitoring sample and design a temperature measuring conduit and a temperature measuring condensing pipe; S2. Layout the temperature measuring points; S3. Install the temperature measuring conduit, the temperature measuring condensing pipe and the temperature measuring wire; S4. Pour the concrete and measure the temperature of the mass concrete to obtain temperature data; S5. Analyze the temperature data and judge the influence of the temperature difference between the inside and the surface of the mass concrete for permanent support on the concrete cracks based on the analysis results.

[0007] In a preferred embodiment, in step S1, when selecting a diaphragm wall monitoring sample and designing a temperature measuring conduit and a condensing pipe, it includes: Select three diaphragm walls with different heights as monitoring samples. Three groups of temperature measuring conduits are arranged on the left, middle and right sides of each diaphragm wall, with 3 roots in each group. The bottom of the temperature measuring conduit is flush with the bottom of the diaphragm wall, and the top is 1 m above the ground. The bottom end of the temperature measuring conduit is sealed. Three temperature measuring wires with different lengths are arranged in each temperature measuring conduit. One group of U-shaped temperature measuring condensing pipes is arranged on the front and back sides of each diaphragm wall, and the ends of the temperature measuring condensing pipes on the front and back sides are connected. The distance between the horizontal pipe segments of the U-shaped temperature measuring condensing pipe is 2 m, and the distance between the vertical pipe segments is 1 m. The position where the temperature measuring condensing pipe contacts the diaphragm wall steel bars is welded.

[0008] In a preferred embodiment, in step S2, the layout of temperature measurement points includes: three conduit temperature measurement points are provided on each temperature measurement conduit. The conduit temperature measurement points are respectively arranged in the middle of the wall, 1000 mm from the bottom of the diaphragm wall, and 2000 mm from the bottom of the crown beam in the vertical direction, and are respectively arranged in the middle of the wall, 100 mm from one side edge, and 1000 mm from one side edge in the horizontal direction. And a control observation hole is set in the foundation pit as the soil temperature measurement point for observing the soil temperature in the same period.

[0009] In a preferred embodiment, in step S3, the installation of the temperature measurement conduit, the temperature measurement condensing pipe and the temperature measurement wire includes: S31. Make length marks on the temperature measurement wire, and the mark positions respectively correspond to the three conduit temperature measurement points on each temperature measurement conduit; S32. Install the temperature measurement condensing pipe during the production of the steel reinforcement cage; S33. Lower the steel reinforcement cage; S34. Install the temperature measurement conduit and the temperature measurement wire: Install 9 temperature measurement conduits in three groups along the horizontal direction in the middle of the wall, 100 mm from one side edge, and 1000 mm from one side edge respectively. Each group of 3 is arranged at intervals in the same vertical plane. The temperature measurement conduits are respectively welded and fixedly connected to the diaphragm wall steel bars in contact. Install the temperature measurement wire. The top port of the temperature measurement wire is fixed with wire, and the bottom is fixed at the bottom of the temperature measurement conduit through a nylon rope.

[0010] In a preferred embodiment, in step S4, pour concrete and measure the temperature of the mass concrete to obtain temperature data, including: Pour concrete through the grouting pipe. After pouring is completed, pour cement slurry into the temperature measurement conduit. The cement slurry starts to measure the temperature within 4 hours after the concrete pouring is completed. Record the temperature when entering the mold. Use a multi-channel temperature inspection instrument to measure the temperature continuously, and record once at the same time interval. When the temperature difference between the mass concrete temperature and the ambient temperature is less than 20 °C, stop measuring the temperature. After the temperature measurement time period ends, export the saved data to form a temperature data list and a curve list.

[0011] In a preferred embodiment, in step S5, analyze the temperature data, including: Analysis of temperature change trend: Observe the temperature change curve of each temperature measurement point over time, and compare the temperature changes of the temperature measurement points at different depths and horizontal positions; Analysis of temperature gradient in the thickness direction: Calculate the temperature difference between the temperature measurement points at different depths to obtain the temperature gradient in the thickness direction; Analysis of temperature gradient in the horizontal direction: Analyze the temperatures of the temperature measurement points at different positions on the same horizontal plane to understand the temperature uniformity in the horizontal direction.

[0012] In a preferred embodiment, in step S5, judging the influence of the temperature difference between the inside and the surface of the mass concrete of the permanent support on the concrete cracks based on the analysis results includes: Evaluating the crack risk: During the concrete temperature rise stage, if the temperature gradient between the temperature measurement points of the conduits near the surface and the center is greater than 25 °C / m, then evaluate the risk of concrete cracking. Temperature control measures need to be adopted, the condensing pipes are activated, and condensed water is injected. The flow rate of the condensed water is controlled between 1.2 - 2 m / s, and the temperature difference between the inlet and outlet of the condensed water is controlled between 5 - 10 °C. During the injection process of the condensed water, pay attention to the temperature changes at each temperature measurement point at all times, and pay attention to whether the cooling rate of the concrete inside the diaphragm wall is controlled within 2 °C / d; during the concrete hardening process, by monitoring the soil temperature, obtain the heat dissipation rate of the concrete to the surrounding soil. If the soil temperature rises rapidly and remains in a high-temperature environment continuously, it indicates that the concrete dissipates heat slowly and the internal temperature is too high, increasing the crack risk. If the soil temperature changes smoothly, it indicates that the concrete dissipates heat normally, which is conducive to evaluating the stability of the internal temperature field of the concrete.

[0013] In a preferred embodiment, it further includes: evaluating the influence on durability and the effect of the temperature control measures: Influence on durability: Analyze the influence of temperature changes on the durability of the concrete. When the internal temperature of the mass concrete exceeds 65 °C and it is in a high-temperature environment for a long time, its durability will be reduced; Effect of temperature control measures: Set the temperature control target value, compare the actually measured temperature data with the temperature control target value, and evaluate the effectiveness of the temperature control measures. When the temperature difference at each temperature measurement point does not exceed 25 °C specified by the design after the condensed water cooling measure is adopted, it indicates that the temperature control measure is effective; if the temperature control does not reach the expected target, targeted adjustment suggestions are put forward. Among them, if the temperature peak exceeds 65 °C, increase the flow rate or density of the condensing pipes. If the cooling rate of the concrete inside the diaphragm wall is greater than 2 °C / d, adjust the insulation measures.

[0014] In a preferred embodiment, the control observation holes are drilled with a geological drill or an anchor drill, and soil temperature measurement conduits are arranged. The length of the soil temperature measurement conduits is the same as the depth of the diaphragm wall. The height of the temperature measurement points of the soil temperature measurement conduits is the same as the temperature measurement points of the conduits of the diaphragm wall, and the same medium cement slurry is injected into the soil temperature measurement conduits.

[0015] The present invention also provides a temperature measurement system for mass concrete supported by diaphragm walls, comprising: temperature measurement conduits, temperature measurement wires, and temperature measurement condensate pipes. The three groups of temperature measurement conduits are respectively arranged horizontally on the left, middle, and right sides of each diaphragm wall, and each group is symmetrically provided with three temperature measurement conduits, which are respectively located at the positions near the front side, in the middle, and near the rear side of the diaphragm wall. The bottom of the temperature measurement conduits is flush with the bottom of the diaphragm wall, and the top extends above the ground. Three temperature measurement points are arranged vertically on each temperature measurement conduit. Three temperature measurement wires of different lengths are arranged in each temperature measurement conduit, and the lengths of the three temperature measurement wires in each temperature measurement conduit respectively correspond to the three temperature measurement points of each temperature measurement conduit. A group of U-shaped temperature measurement condensate pipes is arranged on each of the front and rear sides of each diaphragm wall, and one ends of the temperature measurement condensate pipes on the front and rear sides are connected, and the other ends extend upward above the ground. A control observation hole is arranged on one side of the diaphragm wall in the foundation pit, and a soil body temperature measurement conduit is arranged in the control observation hole, and soil body temperature measurement points are arranged thereon.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: By arranging temperature measurement conduits and temperature measurement condensate pipes in the diaphragm wall, arranging conduit temperature measurement points and soil body temperature measurement points, and continuously measuring temperature by using temperature measurement wires and a multi-channel temperature inspection instrument, the temperature measurement wires can be recycled, effectively saving costs and ensuring accurate concrete temperature measurement and data. At the same time, it provides supporting data for the temperature difference control of mass concrete for permanent support, so as to reduce the influence of concrete cracks. And it accumulates experience for judging the curing time, adjusting the construction progress, and arranging the pouring sequence, etc. Description of the Drawings

[0017] Figure 1 is the method flow chart of the present invention; Figure 2 is the layout schematic diagram of the temperature measurement conduits and temperature measurement condensate pipes of the present invention; Figure 3 is the three-dimensional view of the temperature measurement point setting of the present invention; Figure 4 is the plan view of the temperature measurement point setting of the present invention; Figure 5 is the elevation view of the conduit temperature measurement point setting of the present invention.

[0018] Description of the Reference Numerals: 200, temperature measurement conduit; 201, diaphragm wall; 202, temperature measurement condensate pipe; 203, conduit temperature measurement point; 204, soil body temperature measurement point. Detailed Embodiments

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0020] Embodiment 1 As Figures 1 to 5 shown, the large-volume concrete temperature measurement method for diaphragm wall support of the present invention includes the following steps: Step S1: Select the diaphragm wall monitoring samples and design the temperature measurement conduits and temperature measurement condensing pipes.

[0021] Specifically, step S1 includes: Select three diaphragm walls 200 with different heights as the monitoring samples. Three groups of temperature measurement conduits 201 are arranged on the left, middle, and right sides of each diaphragm wall, with 3 conduits in each group. And the 3 temperature measurement conduits 201 are respectively located at the positions close to the front side, middle, and rear side of the diaphragm wall. The bottom of the temperature measurement conduit 201 is flush with the bottom of the diaphragm wall, and the top is 1 m above the ground. And the bottom end of the temperature measurement conduit 201 is sealed and filled with cement slurry to prevent concrete from entering the temperature measurement pipe. Three temperature measurement wires with different lengths are arranged in each temperature measurement conduit 201, and the temperature measurement wires with corresponding lengths are selected according to the height of the diaphragm wall. One group of U-shaped temperature measurement condensing pipes 202 is arranged on each of the front and rear sides of each diaphragm wall, and one end of the temperature measurement condensing pipes 202 on the front and rear sides is connected, and the other end extends upward above the ground. One group of temperature measurement condensing pipes 202 is arranged between the temperature measurement conduits 201 close to the front side and the middle, and the other group of temperature measurement condensing pipes 202 is arranged between the temperature measurement conduits 201 close to the rear side and the middle, and the two groups of temperature measurement condensing pipes 202 are symmetrically arranged. In this embodiment, the temperature measurement conduit 201 uses a steel casing with an inner diameter of 28 mm, a wall thickness of 4 mm, and a length of 35 m. The inner diameter of the U-shaped temperature measurement condensing pipe 202 is 28 mm. The distance of the horizontal pipe section in the temperature measurement condensing pipe 202 is 2 m, and the distance of the vertical pipe section is 1 m. The position where the temperature measurement condensing pipe contacts the diaphragm wall steel bars is welded.

[0022] Step S2: Arrange the temperature measurement points, including: Three conduit temperature measurement points 203 are arranged on each temperature measurement conduit 201. The conduit temperature measurement points 203 are respectively arranged in the middle of the wall, at a position 1000 mm from the bottom of the diaphragm wall (such as Figure 5 the middle height h1) and at a position 2000 mm from the bottom of the capping beam (such as Figure 5The medium-height h2), are horizontally arranged in the middle of the wall, 100 mm away from one edge, and 1000 mm away from one edge respectively, and a control observation hole is set in the foundation pit as the soil temperature measurement point 204 for observing the soil temperature in the same period. The observation hole is drilled with a geological drill or an anchor drill, and a soil temperature measurement conduit is arranged. The length of the soil temperature measurement conduit is the same as the depth of the diaphragm wall. The height of the temperature measurement point of the soil temperature measurement conduit is the same as the temperature measurement point of the diaphragm wall. The soil temperature measurement conduit is filled with cement slurry of the same medium.

[0023] Step S3: Install the temperature measurement conduit, the temperature measurement condensing pipe and the temperature measurement wire.

[0024] Specifically, step S3 includes: Step S31: Make length marks on the temperature measurement wire, and the mark positions correspond to the three temperature measurement points on each temperature measurement conduit respectively.

[0025] Step S32: Install the temperature measurement condensing pipe 202 during the production process of the diaphragm wall reinforcement cage. Since the overall structure of the temperature measurement condensing pipe is relatively large, it needs to be installed during the production process of the reinforcement cage, and the installation of the temperature measurement condensing pipe is carried out while the reinforcement cage is being made. And because the diaphragm wall reinforcement cage needs to be lifted by two machines, the temperature measurement wire cannot be preset in advance and needs to be arranged after the reinforcement cage is lowered.

[0026] Step S33: Lower the reinforcement cage.

[0027] Step S34: Install the temperature measurement conduit and the temperature measurement wire: Install 9 temperature measurement conduits in three groups along the horizontal direction in the middle of the wall, 100 mm away from one edge, and 1000 mm away from one edge respectively. Each group of 3 is arranged at intervals in the same vertical plane. The temperature measurement conduits are fixedly connected to the adjacent diaphragm wall reinforcement by welding. Install the temperature measurement wire. The top port of the temperature measurement wire is fixed with wire ties, and the bottom is fixed to the temperature measurement conduit by a nylon rope.

[0028] Since the depth of the diaphragm wall is relatively large, it is difficult to accurately arrange the temperature measurement points at the predetermined depth position, and it is very difficult to accurately control the depth of the temperature measurement points. Therefore, we make length marks on the temperature measurement wire. For example, the mark positions are 8 m, 20 m, and 40 m respectively.

[0029] Step S4: Pour concrete and measure the temperature of mass concrete to obtain temperature data. After the steel reinforcement cage is lowered into the trench, concrete is poured through the grouting pipe. After pouring is completed, cement slurry is poured into the temperature measuring conduits. The cement slurry shall have the same grade as the poured concrete to ensure that the temperature measuring conduits and the diaphragm wall are of the same medium. The temperature measurement starts within 4 hours after the concrete pouring is completed. Record the temperature when it enters the mold. Use a multi-channel temperature inspection instrument to conduct continuous temperature measurement and record it every 30 minutes. When the temperature difference between the concrete pouring body and the ambient temperature is less than 20 °C, stop the temperature measurement. After the temperature measurement time period ends, export the saved data to form a temperature data list and a curve list.

[0030] If a large temperature difference between the inside and the surface is found during the temperature measurement stage, low-heat or medium-heat cement can be selected to reduce the amount of heat generated by hydration. Appropriately increase mineral admixtures, which can replace part of the cement, reduce the heat of hydration, and improve the workability of the concrete at the same time. Optimize the aggregate gradation, use continuously graded coarse aggregates, reduce the void ratio, reduce the cement consumption, and thus reduce the heat of hydration.

[0031] Step S5: Analyze the temperature data and judge the influence of the temperature difference between the inside and the surface of the mass concrete for permanent support on the concrete cracks based on the analysis results.

[0032] Further, in step S5, the analysis of the temperature data includes: Analysis of temperature change trend: Observe the temperature change curves of each temperature measurement point over time, and compare the temperature changes of the temperature measurement points at different depths and horizontal positions. Analysis of temperature gradient in the thickness direction: Calculate the temperature difference between the temperature measurement points at different depths to obtain the temperature gradient in the thickness direction. Analysis of temperature gradient in the horizontal direction: Analyze the temperatures of the temperature measurement points at different positions on the same horizontal plane to understand the temperature uniformity in the horizontal direction.

[0033] Further, in step S5, judging the influence of the temperature difference between the inside and the surface of the mass concrete for permanent support on the concrete cracks based on the analysis results includes: Evaluating crack risk: During the concrete temperature rise stage, if the temperature gradient between the temperature measurement points near the surface and the central temperature measurement points is greater than 25 °C / m, then evaluate the risk of concrete cracking. Temperature control measures need to be adopted, start the condensing pipe, inject condensed water, and control the flow rate of the condensed water between 1.2 - 2 m / s. The condensed water can timely absorb the heat inside the concrete and circulate it away, maintaining the stability of the internal temperature of the concrete. This flow rate range can ensure that while the condensed water takes away the heat of the concrete, it will not cause excessive scouring pressure on the pipeline due to too fast a flow rate, nor will it reduce the cooling efficiency due to too slow a flow rate. Control the temperature difference between the inlet and outlet of the condensed water within 5 - 10 °C. If the temperature difference is too large, it may lead to too large a temperature gradient inside the concrete, increasing the risk of concrete cracking; if the temperature difference is too small, it may indicate insufficient cooling efficiency. During the process of injecting condensed water, always pay attention to the temperature changes at each temperature measurement point, and pay attention to whether the cooling rate of the concrete inside the diaphragm wall is controlled within 2 °C / d; during the hardening process of the concrete, by monitoring the soil temperature, obtain the heat dissipation rate of the concrete to the surrounding soil. If the soil temperature rises rapidly and remains in a high-temperature environment continuously, it indicates that the concrete dissipates heat slowly and the internal temperature is too high, increasing the crack risk. If the soil temperature changes smoothly, it indicates that the concrete dissipates heat normally, which is conducive to evaluating the stability of the internal temperature field of the concrete.

[0034] Durability impact: Analyze the impact of temperature changes on the durability of concrete. When the internal temperature of the large-volume concrete exceeds 65 °C and it is in a high-temperature environment for a long time, its durability will be reduced.

[0035] Effect of temperature control measures: Set the temperature control target value, compare the actually measured temperature data with the temperature control target value, and evaluate the effectiveness of the temperature control measures. When the temperature difference at each temperature measurement point does not exceed 25 °C specified in the design after adopting the condensed water cooling measure, it indicates that the temperature control measure is effective; if the temperature control does not reach the expected target, put forward targeted adjustment suggestions. Among them, if the temperature peak exceeds 65 °C, increase the flow rate or density of the condensing pipe. If the cooling rate of the concrete inside the diaphragm wall is greater than 2 °C / d, adjust the insulation measure.

[0036] Example 2 The present invention also provides a temperature measuring device for mass concrete supported by diaphragm walls, comprising: temperature measuring conduits 201, temperature measuring wires, and temperature measuring condensing pipes 202. The three groups of temperature measuring conduits 201 are respectively arranged horizontally on the left, middle, and right sides of each diaphragm wall 200, and three temperature measuring conduits 201 are symmetrically arranged in each group. The three temperature measuring conduits 201 are respectively located at positions close to the front side, in the middle, and close to the rear side of the diaphragm wall. The bottom of the temperature measuring conduit 201 is flush with the bottom of the diaphragm wall, and the top extends above the ground. Three temperature measuring points 203 are arranged vertically on each temperature measuring conduit 201. Three temperature measuring wires with different lengths are arranged in each temperature measuring conduit 201, and the lengths of the three temperature measuring wires in each temperature measuring conduit 201 correspond to the three temperature measuring points 203 of each temperature measuring conduit 201 respectively. The top ports of the temperature measuring wires are fixed with binding wires, and the bottoms are fixed to the temperature measuring conduits through nylon ropes. A group of U-shaped temperature measuring condensing pipes 202 are arranged on each of the front and rear sides of each diaphragm wall 200, and one ends of the temperature measuring condensing pipes 202 on the front and rear sides are connected, and the other ends extend upward above the ground.

[0037] Further, the top of the temperature measuring conduit 201 is 1 m higher than the ground, and the bottom end of the temperature measuring conduit 201 is sealed. The temperature measuring conduit 201 is filled with cement slurry having the same mix ratio as the cast concrete to prevent the cast concrete from entering the temperature measuring pipe.

[0038] Further, one group of temperature measuring condensing pipes 202 is arranged between the temperature measuring conduit 201 close to the front side and the middle temperature measuring conduit 201, and the other group of temperature measuring condensing pipes 202 is arranged between the temperature measuring conduit 201 close to the rear side and the middle temperature measuring conduit 201, and the two groups of temperature measuring condensing pipes 202 are symmetrically arranged. The inner diameter of the U-shaped temperature measuring condensing pipe 202 is 28 mm, the vertical distance between the horizontal pipe sections in the temperature measuring condensing pipe 202 is 2 m, the horizontal distance between the vertical pipe sections is 1 m, and the positions where the temperature measuring conduits 201 and the temperature measuring condensing pipes 202 are in contact with the diaphragm wall steel bars are welded.

[0039] Further, the three temperature measuring points 203 on each temperature measuring conduit 201 are respectively arranged vertically in the middle of the wall, at a position 1000 mm from the bottom of the diaphragm wall (such as Figure 5 the height h1 in the figure) and at a position 2000 mm from the bottom of the capping beam (such as Figure 5 the height h2 in the figure), and are respectively arranged horizontally in the middle of the wall, at a position 100 mm from one edge, and at a position 1000 mm from one edge.

[0040] Furthermore, a control observation hole is arranged on one side of the diaphragm wall in the foundation pit. A soil temperature measuring conduit is arranged in the control observation hole, and soil temperature measuring points 204 are arranged thereon for observing the soil temperature in the same period. The observation hole is drilled by a geological drill or an anchor drill, and the soil temperature measuring conduit is arranged. The length of the soil temperature measuring conduit is the same as the depth of the diaphragm wall, and the height of the temperature measuring point of the soil temperature measuring conduit is the same as the temperature measuring point position of the diaphragm wall.

[0041] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A temperature measurement method for mass concrete supported by diaphragm walls, characterized in that: It includes the following steps: S1. Select the monitoring samples of the diaphragm wall and design the temperature measuring conduits and temperature measuring condensing pipes; S2. Layout the temperature measuring points; S3. Install the temperature measuring conduits, temperature measuring condensing pipes and temperature measuring wires; S4. Pour the concrete and measure the temperature of the mass concrete to obtain the temperature data; S5. Analyze the temperature data and judge the influence of the temperature difference between the inside and the surface of the mass concrete of the permanent support on the concrete cracks based on the analysis results.

2. The large-volume concrete temperature measurement method for diaphragm wall support according to claim 1, wherein: In step S1, when selecting the monitoring samples of the diaphragm wall and designing the temperature measuring conduits and condensing pipes, it includes: Select three diaphragm walls with different heights as the monitoring samples. Three groups of temperature measuring conduits are arranged on the left, middle and right sides of each diaphragm wall, with 3 conduits in each group. The bottom of the temperature measuring conduits is flush with the bottom of the diaphragm wall, and the top is 1m above the ground. The bottom end of the temperature measuring conduit is sealed. Three temperature measuring wires with different lengths are arranged in each temperature measuring conduit. One group of U-shaped temperature measuring condensing pipes is arranged on the front and back sides of each diaphragm wall, and one end of the temperature measuring condensing pipes on the front and back sides is connected. The distance of the horizontal pipe section in the U-shaped temperature measuring condensing pipe is 2m, and the distance of the vertical pipe section is 1m. The position where the temperature measuring condensing pipe contacts the diaphragm wall steel bars is welded.

3. The large-volume concrete temperature measurement method for diaphragm wall support according to claim 1, characterized in that: In step S2, when laying out the temperature measuring points, it includes: Three conduit temperature measuring points are arranged on each temperature measuring conduit. The conduit temperature measuring points are arranged vertically in the middle of the wall, 1000mm from the bottom of the diaphragm wall and 2000mm from the bottom of the capping beam respectively, and horizontally in the middle of the wall, 100mm from one edge and 1000mm from one edge respectively. One control observation hole is set in the foundation pit as the soil temperature measuring point for observing the soil temperature in the same period.

4. The large-volume concrete temperature measurement method for diaphragm wall support according to claim 3, characterized in that: In step S3, when installing the temperature measuring conduits, temperature measuring condensing pipes and temperature measuring wires, it includes: S31. Make marks at each length on the temperature measuring wires, and the marked positions correspond to the three conduit temperature measuring points on each temperature measuring conduit respectively; S32. Install the temperature measuring condensing pipes during the production of the steel cage; S33. Lower the steel cage; S34. Install the temperature measuring conduits and temperature measuring wires: Install 9 temperature measuring conduits in three groups horizontally in the middle of the wall, 100mm from one edge and 1000mm from one edge respectively. Each group of 3 conduits is arranged at intervals in the same vertical plane. The temperature measuring conduits are welded and fixed to the contacted diaphragm wall steel bars respectively. Install the temperature measuring wires. The top ports of the temperature measuring wires are fixed with wire ties, and the bottom is fixed at the bottom of the temperature measuring conduits through nylon ropes.

5. The temperature measurement method for mass concrete of diaphragm wall support according to claim 1, wherein: In step S4, when pouring the concrete and measuring the temperature of the mass concrete to obtain the temperature data, it includes: Pour the concrete through the grouting pipe. After pouring is completed, pour cement slurry into the temperature measuring conduits. The cement slurry starts to measure the temperature within 4 hours after the concrete pouring is completed, record the temperature when entering the mold, and use a multi-channel temperature inspection instrument to measure the temperature continuously, record once at the same interval of time segments. When the temperature difference between the mass concrete and the ambient temperature is less than 20°C, stop measuring the temperature. After the temperature measuring time period ends, export the saved data to form a temperature data list and a curve list.

6. The large-volume concrete temperature measurement method for diaphragm wall support according to claim 5, characterized in that: In step S5, when analyzing the temperature data, it includes: Analysis of temperature change trend: Observe the temperature change curves of each temperature measurement point over time, and compare the temperature changes of the temperature measurement points at different depths and horizontal positions; Analysis of temperature gradient in the thickness direction: Calculate the temperature difference between the temperature measurement points at different depths to obtain the temperature gradient in the thickness direction; Analysis of temperature gradient in the horizontal direction: Analyze the temperatures of the temperature measurement points at different positions on the same horizontal plane to understand the temperature uniformity in the horizontal direction.

7. The large-volume concrete temperature measurement method for diaphragm wall support according to claim 6, characterized in that: In step S5, judge the influence of the internal and surface temperature difference of the mass concrete of the permanent support on the concrete cracks based on the analysis results, including: Evaluate the crack risk: During the concrete heating stage, if the temperature gradient between the temperature measurement points of the conduits near the surface and the center conduits is greater than 25 °C / m, then evaluate the risk of concrete cracking. Temperature control measures need to be adopted, the condenser pipes are activated, and condensed water is injected. The flow rate of the condensed water is controlled between 1.2 - 2 m / s, and the temperature difference between the inlet and outlet of the condensed water is controlled between 5 - 10 °C. During the injection process of the condensed water, pay attention to the temperature changes of each temperature measurement point at all times, and pay attention to whether the cooling rate of the concrete inside the diaphragm wall is controlled within 2 °C / d; during the hardening process of the concrete, by monitoring the soil temperature, obtain the heat dissipation rate of the concrete to the surrounding soil. If the soil temperature rises rapidly and remains in a high-temperature environment continuously, it indicates that the concrete dissipates heat slowly and the internal temperature is too high, increasing the crack risk. If the soil temperature changes smoothly, it indicates that the concrete dissipates heat normally, which is conducive to evaluating the stability of the internal temperature field of the concrete.

8. The large-volume concrete temperature measurement method for diaphragm wall support according to claim 7, characterized in that: It also includes: Evaluate the influence on durability and the effect of temperature control measures: Influence on durability: Analyze the influence of temperature change on the durability of concrete. When the internal temperature of the mass concrete exceeds 65 °C and it is in a high-temperature environment for a long time, its durability will be reduced; Effect of temperature control measures: Set the temperature control target value, compare the actually measured temperature data with the temperature control target value, and evaluate the effectiveness of the temperature control measures. When the temperature difference between each temperature measurement point does not exceed 25 °C specified in the design after adopting the condensed water cooling measure, it indicates that the temperature control measure is effective; if the temperature control does not reach the expected target, put forward targeted adjustment suggestions. Among them, if the temperature peak exceeds 65 °C, increase the flow rate or density of the condenser pipes; if the cooling rate of the concrete inside the diaphragm wall is greater than 2 °C / d, adjust the insulation measures.

9. The large-volume concrete temperature measurement method for diaphragm wall support according to claim 3, wherein: The reference observation holes are drilled using a geological drill or a rock bolt drill, and soil temperature measurement conduits are arranged. The length of the soil temperature measurement conduits is the same as the depth of the diaphragm wall. The height of the temperature measurement points of the soil temperature measurement conduits is the same as the temperature measurement points of the diaphragm wall. The same medium cement slurry is injected into the soil temperature measurement conduits.

10. A temperature measurement system for mass concrete supported by diaphragm walls, characterized in that: It includes: Temperature measuring conduits (201), temperature measuring wires, and temperature measuring condensing pipes (202). The three groups of temperature measuring conduits (201) are respectively arranged horizontally on the left, middle, and right sides of each diaphragm wall (200), and three temperature measuring conduits (201) are symmetrically arranged in each group. The three temperature measuring conduits (201) are respectively located at the positions close to the front side, the middle, and the rear side of the diaphragm wall. The bottom of the temperature measuring conduit (201) is flush with the bottom of the diaphragm wall, and the top extends above the ground. Three temperature measuring points (203) are arranged vertically on each temperature measuring conduit (201). Three temperature measuring wires of different lengths are arranged in each temperature measuring conduit (201). The lengths of the three temperature measuring wires in each temperature measuring conduit (201) respectively correspond to the three temperature measuring points (203) of each temperature measuring conduit (201). A group of U-shaped temperature measuring condensing pipes (202) are arranged on each of the front and rear sides of each diaphragm wall (200), and one ends of the temperature measuring condensing pipes (202) on the front and rear sides are connected and the other ends extend upward above the ground. A control observation hole is arranged on one side of the diaphragm wall in the foundation pit. A soil temperature measuring conduit is arranged in the control observation hole, and soil temperature measuring points (204) are arranged thereon.

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