Temperature measurement method for large volume concrete supported by underground continuous wall

Abstract

The present invention discloses a method for measuring temperature of large-volume concrete supported by underground continuous walls, comprising the following steps: S1, selecting underground continuous wall monitoring samples and designing temperature measuring tubes and temperature measuring condenser tubes; S2, arranging temperature measuring points; S3, installing temperature measuring tubes, temperature measuring condenser tubes, and temperature measuring wires; S4, pouring concrete, and measuring the temperature of the large-volume concrete to obtain temperature data; S5, analyzing the temperature data, and judging the influence of the temperature difference between the inside and outside of the permanent support large-volume concrete on concrete cracks based on the analysis results. The method of the present invention can ensure that the concrete temperature measurement and data are accurate, and at the same time, provide supporting data for the temperature difference control of the permanent support large-volume concrete, thereby reducing the influence of concrete cracks, and accumulate experience for judging the curing time, adjusting the construction progress, and arranging the pouring sequence.

Description

Technical Field

[0001] The present invention relates to the technical field of underground continuous wall support temperature measurement, and in particular to a method and system for measuring the temperature of large-volume concrete supported by an underground continuous wall. Background Art

[0002] With the acceleration of urbanization, infrastructure construction, such as high-rise buildings and large-scale underground projects, is booming. Underground diaphragm walls are widely used as an effective form of deep foundation pit support and underground structure exterior wall. During the construction of underground diaphragm walls, pouring large volumes of concrete is a key step. However, the impact of temperature on the durability of underwater concrete in permanent support forms and concrete encased in soil is currently unknown, making temperature measurement and monitoring of these concrete structures crucial.

[0003] Due to the large size of large-volume concrete, the heat released during cement hydration accumulates within the concrete, which is difficult to dissipate quickly. The cement hydration reaction is typically most intense in the early stages after pouring, generating significant heat and causing a sharp rise in the concrete's internal temperature. For example, the peak heat of cement hydration for common C30 concrete typically occurs two to three days after pouring, with the internal temperature rising by 30°C to 50°C compared to the pouring temperature. Furthermore, due to the unique characteristics of underground diaphragm walls, with soil layers on both sides, internal heat is difficult to dissipate, resulting in a significant temperature difference between the inside and outside. This high internal temperature contrasts sharply with the surrounding soil temperature, creating a large temperature gradient between the interior and surface of the concrete. Excessive temperature gradients can cause non-uniform deformation in the concrete, leading to thermal stresses. When thermal stresses exceed the tensile strength of the concrete, they can cause cracking. The appearance of cracks not only affects the appearance of the underground diaphragm wall but also severely impairs its load-bearing capacity, waterproofing, and durability, posing a significant safety hazard to the project.

[0004] Conventional foundation slab temperature measurement methods require installation after reinforcement is tied and before concrete is poured. The temperature measuring wire needs to be tied to a steel bar, and its temperature-sensing part should be at the temperature measurement point. During tying, the temperature measuring wire should not be in direct contact with the steel bar. However, this temperature measurement method will bring the following problems to underground continuous wall temperature measurement:

[0005] 1. It is difficult to control the temperature measuring line from contacting the steel bars during the pouring process, which often leads to inaccurate temperature measurement data after the pouring is completed, and cannot reflect the actual temperature inside the concrete, causing major misunderstandings in construction management. 2. The temperature measuring line is tied to the steel bars. When the steel bars are fixed on the wall column steel bars, the steel bars are easy to shift during the pouring process, and even the temperature measurement is broken, resulting in inaccurate temperature measurement data and unable to be measured. 3. During the hoisting of the underground continuous wall steel cage, the temperature measuring line is easily damaged, resulting in the inability to measure data later. 4. The pre-buried temperature measuring line cannot be recycled when measuring the temperature of large-volume concrete, and the cost is relatively high. 5. The traditional temperature measurement method is only for temperature measurement. If there is a large temperature difference between the inside and the outside, conventional methods such as covering and insulation can only be used, but this method is not suitable for underground continuous walls. Summary of the Invention

[0006] The purpose of the present invention is to provide a temperature measurement method and system for large-volume concrete supported by underground continuous walls, so as to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides a method for measuring temperature of large-volume concrete supported by an underground continuous wall, comprising the following steps:

[0008] S1. Select underground continuous wall monitoring samples and design temperature measuring tubes and temperature measuring condenser tubes;

[0009] S2. Layout of temperature measurement points;

[0010] S3. Install the temperature measuring tube, temperature measuring condenser tube and temperature measuring wire;

[0011] S4. pouring concrete and measuring the temperature of large-volume concrete to obtain temperature data;

[0012] S5. Analyze the temperature data and, based on the analysis results, determine the impact of the temperature difference between the inside and outside of permanent support mass concrete on concrete cracks.

[0013] In a preferred embodiment, in step S1, an underground continuous wall monitoring sample is selected, and temperature measuring tubes and condenser tubes are designed, including: selecting three underground continuous walls of different heights as monitoring samples, arranging three groups of temperature measuring tubes on the left, middle and right sides of each underground continuous wall, respectively, with 3 tubes in each group, the bottom of the temperature measuring tube is flush with the bottom of the underground continuous wall, the top is 1m above the ground, and the bottom end of the temperature measuring tube is sealed, three temperature measuring wires of different lengths are arranged in each temperature measuring tube, and a group of "J"-shaped temperature measuring condenser tubes are respectively arranged on the front and back sides of each underground continuous wall, and one end of the temperature measuring condenser tubes on the front and back sides are connected, the distance between the horizontal pipe sections in the "J"-shaped temperature measuring condenser tubes is 2m, and the distance between the vertical pipe sections is 1m, and the temperature measuring condenser tubes are welded to the position where they contact the steel bars of the underground continuous wall.

[0014] In a preferred embodiment, in step S2, the temperature measuring points are arranged, including: three tube temperature measuring points are set on each temperature measuring tube, and the tube temperature measuring points are arranged in the middle of the wall, 1000 mm from the bottom of the underground continuous wall, and 2000 mm from the bottom of the crown beam in the vertical direction, and 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 a soil temperature measuring point for observing the soil temperature during the same period.

[0015] In a preferred embodiment, in step S3, installing the temperature measuring conduit, the temperature measuring condenser tube, and the temperature measuring wire includes:

[0016] S31. Mark the lengths of the temperature measuring wires, with the marking positions corresponding to the three temperature measuring points on each temperature measuring catheter.

[0017] S32. Installing the temperature measuring condenser tube during the production process of the steel cage;

[0018] S33, lower the steel cage;

[0019] S34. Install temperature measuring tubes and temperature measuring wires: Divide 9 temperature measuring tubes into three groups and install them horizontally in the middle of the wall, 100mm away from one side edge, and 1000mm away from one side edge. Three tubes in each group are spaced apart in the same vertical plane. The temperature measuring tubes are welded and fixed to the underground continuous wall steel bars they are in contact with. Install the temperature measuring wires. Fix the top end of the temperature measuring wires with a wire tie, and fix the bottom end to the bottom of the temperature measuring tubes with a nylon rope.

[0020] In a preferred embodiment, in step S4, concrete is poured, and the temperature of the mass concrete is measured to obtain temperature data, including: pouring concrete through a grouting pipe, pouring cement slurry into the temperature measuring tube after pouring is completed, starting to measure the temperature of the cement slurry within 4 hours after the concrete pouring is completed, recording the temperature entering the mold, using a multi-channel temperature patrol meter to perform uninterrupted temperature measurement, recording once at the same time interval, when the difference between the temperature of the mass concrete and the ambient temperature is less than 20°C, stopping the temperature measurement, and after the temperature measurement time period ends, exporting the saved data to form a temperature data list and a curve list.

[0021] In a preferred embodiment, in step S5, analyzing the temperature data includes:

[0022] Temperature change trend analysis: observe the temperature change curve of each temperature measuring point over time, and compare the temperature changes of temperature measuring points at different depths and horizontal positions;

[0023] Temperature gradient analysis in thickness direction: Calculate the temperature difference between temperature measurement points at different depths to obtain the temperature gradient in thickness direction;

[0024] Horizontal temperature gradient analysis: Analyze the temperature of temperature measuring points at different positions on the same horizontal plane to understand the temperature uniformity in the horizontal direction.

[0025] In a preferred embodiment, in step S5, determining the effect of the temperature difference between the inside and outside of the permanent support mass concrete on concrete cracks based on the analysis results includes:

[0026] Assess the risk of cracks: During the concrete heating stage, if the temperature gradient between the duct temperature measuring point near the surface and the duct temperature measuring point in the center is greater than 25°C / m, the risk of concrete cracks is assessed and temperature control measures are required. The condenser is activated and condensate is added. The condensate flow rate is controlled between 1.2 and 2 m / s, and the temperature difference between the condensate inlet and outlet is controlled between 5 and 10°C. During the condensate pouring process, always pay attention to the temperature changes at each temperature measuring point and whether the cooling rate of the concrete inside the underground continuous wall is controlled within 2°C / d. During the concrete hardening process, the soil temperature is monitored to 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, it indicates that the concrete dissipates heat slowly and the internal temperature is too high, increasing the risk of cracks. If the soil temperature changes smoothly, it indicates that the concrete dissipates heat normally, which is conducive to evaluating the stability of the temperature field inside the concrete.

[0027] In a preferred embodiment, the method further includes: evaluating the impact of durability and the effectiveness of temperature control measures:

[0028] Durability impact: Analyze the impact of temperature changes on concrete durability. When the internal temperature of large-volume concrete exceeds 65°C and is in a high temperature environment for a long time, its durability will be reduced.

[0029] Effect of temperature control measures: Set the temperature control target value, compare the actual measured temperature data with the temperature control target value, and evaluate the effectiveness of the temperature control measures. When the condensation water cooling measure is adopted, if the temperature difference at each temperature measuring point does not exceed the design requirement of 25°C, it indicates that the temperature control measures are effective; if the temperature control does not reach the expected target, then make targeted adjustment suggestions. Among them, if the temperature peak exceeds 65°C, increase the flow rate or density of the condenser pipe; if the cooling rate of the concrete inside the underground continuous wall is greater than 2°C / d, adjust the insulation measures.

[0030] In a preferred embodiment, the control observation hole is drilled using a geological drill or an anchor drilling rig, and a soil temperature measuring tube is laid. The length of the soil temperature measuring tube is consistent with the depth of the underground continuous wall, the height of the temperature measuring point of the soil temperature measuring tube is consistent with the temperature measuring point of the underground continuous wall tube, and the soil temperature measuring tube is poured with cement slurry of the same medium.

[0031] The present invention also provides a temperature measurement system for underground continuous wall supporting large-volume concrete, comprising: a temperature measuring conduit, a temperature measuring wire, and a temperature measuring condenser tube. Three groups of temperature measuring conduits are respectively arranged horizontally on the left, middle, and right sides of each underground continuous wall, and each group is symmetrically provided with three temperature measuring conduits. The three temperature measuring conduits are respectively located near the front, middle, and rear sides of the underground continuous wall. The bottom of the temperature measuring conduit is flush with the bottom of the underground continuous wall, and the top extends above the ground. Three temperature measuring conduits are arranged vertically on each temperature measuring conduit. temperature measuring points, and three temperature measuring wires of different lengths are set in each temperature measuring tube. The lengths of the three temperature measuring wires in each temperature measuring tube correspond to the three temperature measuring points of each temperature measuring tube. A group of "X"-shaped temperature measuring condenser tubes are set on the front and back sides of each underground continuous wall, and one end of the temperature measuring condenser tubes on the front and back sides are connected, and the other end extends upward to above the ground. A control observation hole is set on one side of the underground continuous wall in the foundation pit, and a soil temperature measuring tube is set in the control observation hole, on which soil temperature measuring points are arranged.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] This invention installs temperature-measuring conduits and condenser tubes within the underground continuous wall, arranges temperature measurement points on the conduits and on the soil, and uses temperature-measuring wires and multi-channel temperature inspection instruments for continuous temperature measurement. The temperature-measuring wires can be recycled, effectively saving costs and ensuring accurate concrete temperature measurement and data. It also provides supporting data for temperature differential control of large-volume concrete in permanent support, thereby mitigating the impact of concrete cracks. It also accumulates experience for determining curing time, adjusting construction schedules, and arranging pouring sequences. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of the method of the present invention;

[0035] Figure 2 This is a schematic diagram of the arrangement of the temperature measuring conduit and the temperature measuring condenser tube of the present invention;

[0036] Figure 3 A three-dimensional diagram of the temperature measurement point arrangement of the present invention;

[0037] Figure 4 It is a plan view of the temperature measurement point arrangement of the present invention;

[0038] Figure 5 This is an elevation view of the catheter temperature measurement point arrangement of the present invention.

[0039] Description of reference numerals:

[0040] 200. Temperature measuring conduit; 201. Underground continuous wall; 202. Temperature measuring condenser; 203. Conduit temperature measuring point; 204. Soil temperature measuring point. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention are described clearly and completely below. The embodiments of the present invention and all other embodiments obtained by persons of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0042] Example 1

[0043] like Figures 1 to 5 As shown, the temperature measurement method of underground continuous wall supporting large volume concrete of the present invention comprises the following steps:

[0044] Step S1: Select underground continuous wall monitoring samples and design temperature measuring tubes and temperature measuring condenser tubes.

[0045] Specifically, step S1 includes selecting three underground continuous walls 200 of different heights as monitoring samples. Three groups of temperature measuring tubes 201 are arranged on the left, middle, and right sides of each underground continuous wall, with three tubes in each group. The three temperature measuring tubes 201 are located near the front, middle, and back of the underground continuous wall, respectively. The bottoms of the temperature measuring tubes 201 are flush with the bottom of the underground continuous wall, and the tops are 1 meter above the ground. The bottoms of the temperature measuring tubes 201 are sealed and filled with cement slurry to prevent concrete from entering the temperature measuring tubes. Each temperature measuring tube 201 is equipped with three temperature measuring wires of different lengths, with the lengths of the temperature measuring wires selected according to the height of the underground continuous wall. A set of "X"-shaped temperature measuring condenser tubes 202 are installed on the front and back sides of each underground continuous wall. The temperature measuring condenser tubes 202 on both sides are connected at one end and extend upward to the ground at the other end. One set of temperature-measuring condenser tubes 202 is positioned between the front and middle temperature-measuring conduits 201, while the other set is positioned between the rear and middle temperature-measuring conduits 201. The two sets of temperature-measuring condenser tubes 202 are symmetrically arranged. In this embodiment, the temperature-measuring conduits 201 are constructed of 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 "X"-shaped temperature-measuring condenser tubes 202 is 28 mm. The horizontal sections of the temperature-measuring condenser tubes 202 are 2 m apart, and the vertical sections are 1 m apart. The temperature-measuring condenser tubes 202 are welded where they contact the rebar of the underground continuous wall.

[0046] Step S2, arrange the temperature measuring points, including: setting three temperature measuring points 203 on each temperature measuring conduit 201, and the temperature measuring points 203 are arranged in the middle of the wall and 1000mm away from the bottom of the underground continuous wall in the vertical direction (such as Figure 5 Middle height h1) and 2000mm from the bottom of the crown beam (such as Figure 5Middle height h2) are horizontally located in the middle of the wall, 100mm from one edge, and 1000mm from one edge. A control observation hole is set in the foundation pit as soil temperature measurement point 204 to observe the soil temperature during the same period. The observation hole is drilled using a geological drill or anchor drill rig, and a soil temperature measurement conduit is laid. The length of the soil temperature measurement conduit is consistent with the depth of the underground continuous wall, and the temperature measurement point height of the soil temperature measurement conduit is consistent with the underground continuous wall temperature measurement point. The soil temperature measurement conduit is filled with cement slurry of the same medium.

[0047] Step S3: Install the temperature measuring tube, the temperature measuring condenser tube and the temperature measuring wire.

[0048] Specifically, step S3 includes:

[0049] Step S31: Mark the lengths of the temperature measuring wires, with the marked positions corresponding to the three temperature measuring points on each temperature measuring conduit.

[0050] Step S32: Install the temperature-measuring condenser tube 202 during the fabrication of the ground-connected wall reinforcement cage. Due to the large overall size of the temperature-measuring condenser tube, it must be installed during the cage fabrication process. Furthermore, since the ground-connected wall reinforcement cage requires dual cranes for lifting, the temperature-measuring wire cannot be pre-installed and must be installed after the cage is lowered.

[0051] Step S33: lower the steel cage.

[0052] Step S34, install the temperature measuring tubes and temperature measuring wires: divide the 9 temperature measuring tubes into three groups and install them horizontally in the middle of the wall, 100 mm from one side edge, and 1000 mm from one side edge, with 3 tubes in each group spaced apart in the same vertical plane. The temperature measuring tubes are welded and fixed to the underground continuous wall steel bars they are in contact with, and the temperature measuring wires are installed. The top end of the temperature measuring wire is fixed with a wire tie, and the bottom is fixed to the temperature measuring tube with a nylon rope.

[0053] Due to the great depth of the underground continuous wall, it is difficult to accurately arrange the temperature measurement points at the predetermined depth, and it is difficult to precisely control the depth of the temperature measurement points. Therefore, we mark the different lengths on the temperature measurement wire, for example, the marking positions are 8m, 20m, and 40m respectively.

[0054] Step S4: Pour concrete and measure the temperature of the bulk concrete to obtain temperature data: After the steel cage is lowered into the slot, concrete is poured through the grouting pipe. After pouring, cement slurry is poured into the temperature measuring tube. The cement slurry should be of the same grade as the poured concrete, ensuring that the temperature measuring tube and the ground-connected wall are the same medium. The cement slurry temperature is measured within four hours of pouring, and the temperature entering the mold is recorded. A multi-channel temperature monitoring instrument is used for continuous temperature measurement every 30 minutes. Temperature measurement is stopped when the difference between the temperature of the concrete casting and the ambient temperature is less than 20°C. After the temperature measurement period, the saved data is exported to form a temperature data list and a curve list.

[0055] If a large temperature difference between the inside and outside is detected during temperature measurement, low- or medium-heat cement can be used to reduce hydration heat. Appropriately adding mineral admixtures can replace some of the cement, reducing hydration heat and improving concrete workability. Optimizing aggregate gradation, using continuously graded coarse aggregate, reduces void content, and reduces cement usage, further reducing hydration heat.

[0056] Step S5: Analyze the temperature data and determine the effect of the temperature difference between the inside and outside of the permanent support mass concrete on concrete cracks based on the analysis results.

[0057] Furthermore, in step S5, the temperature data is analyzed, including:

[0058] Temperature change trend analysis: observe the temperature change curve of each temperature measuring point over time, and compare the temperature changes of temperature measuring points at different depths and horizontal positions;

[0059] Temperature gradient analysis in thickness direction: Calculate the temperature difference between temperature measurement points at different depths to obtain the temperature gradient in thickness direction;

[0060] Horizontal temperature gradient analysis: Analyze the temperature of temperature measuring points at different positions on the same horizontal plane to understand the temperature uniformity in the horizontal direction.

[0061] Furthermore, in step S5, the influence of the temperature difference between the inside and outside of the permanent support mass concrete on the concrete cracks is determined based on the analysis results, including:

[0062] Assessing Crack Risk: During the concrete heating phase, if the temperature gradient between the surface and center temperature measuring points exceeds 25°C / m, the risk of concrete cracking is assessed. Temperature control measures should be implemented, including activating condenser pipes and adding condenser water. The condenser water flow rate should be controlled between 1.2 and 2 m / s. Condensate water absorbs heat from the concrete and circulates it away, maintaining a stable internal temperature. This flow rate ensures that the condenser water removes heat from the concrete without causing excessive pressure on the pipes due to excessive flow, or reducing cooling efficiency due to excessive flow. The temperature difference between the inlet and outlet condenser water should be controlled between 5 and 10°C. A large temperature difference may lead to a large temperature gradient within the concrete, increasing the risk of cracks. A small temperature difference may indicate insufficient cooling efficiency. During the condensate pouring process, always pay attention to the temperature changes at each temperature measuring point and whether the cooling rate of the concrete inside the underground continuous 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, it indicates that the concrete dissipates heat slowly, the internal temperature is too high, and the risk of cracks increases. 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.

[0063] Impact on durability: Analyze the impact of temperature changes on the durability of concrete. When the internal temperature of large-volume concrete exceeds 65°C and is in a high-temperature environment for a long time, its durability will be reduced.

[0064] Effect of temperature control measures: Set the temperature control target value, compare the actual measured temperature data with the temperature control target value, and evaluate the effectiveness of the temperature control measures. When the condensation water cooling measure is adopted, if the temperature difference at each temperature measuring point does not exceed the design requirement of 25°C, it indicates that the temperature control measures are effective; if the temperature control does not reach the expected target, then make targeted adjustment suggestions. Among them, if the temperature peak exceeds 65°C, increase the flow rate or density of the condenser pipe; if the cooling rate of the concrete inside the underground continuous wall is greater than 2°C / d, adjust the insulation measures.

[0065] Example 2

[0066] The present invention also provides a temperature measurement device for large-volume concrete supported by underground continuous walls, comprising: a temperature measurement conduit 201, a temperature measurement wire, and a temperature measurement condenser tube 202. Three groups of temperature measurement conduits 201 are horizontally arranged on the left, middle, and right sides of each underground continuous wall 200, respectively. Each group includes three symmetrical temperature measurement conduits 201, located near the front, middle, and rear of the underground continuous wall, respectively. The bottoms of the temperature measurement conduits 201 are flush with the bottom of the underground continuous wall, and the tops extend above the ground. Each temperature measurement conduit 201 is vertically provided with three temperature measurement points 203. Three temperature measurement wires of different lengths are installed within each temperature measurement conduit 201, and the lengths of the three temperature measurement wires within each temperature measurement conduit 201 correspond to the three temperature measurement points 203 of each temperature measurement conduit 201. The top ends of the temperature measurement wires are secured with wire ties, and the bottom ends are secured to the temperature measurement conduits with nylon ropes. A set of X-shaped temperature measuring condensation pipes 202 are respectively provided on the front and rear sides of each underground continuous wall 200, and one end of the temperature measuring condensation pipes 202 on the front and rear sides is connected, and the other end extends upward to above the ground.

[0067] Furthermore, the top of the temperature measuring tube 201 is 1 m above the ground, and the bottom of the temperature measuring tube 201 is sealed. The temperature measuring tube 201 is filled with cement slurry with the same proportion as the poured concrete to prevent the poured concrete from entering the temperature measuring tube.

[0068] Furthermore, one set of temperature-measuring condenser tubes 202 is positioned between the temperature-measuring conduit 201 near the front and the middle temperature-measuring conduit 201, while the other set of temperature-measuring condenser tubes 202 is positioned between the temperature-measuring conduit 201 near the rear and the middle temperature-measuring conduit 201. The two sets of temperature-measuring condenser tubes 202 are symmetrically arranged. The inner diameter of the "X"-shaped temperature-measuring condenser tubes 202 is 28 mm. The vertical distance between the horizontal sections of the temperature-measuring condenser tubes 202 is 2 m, and the horizontal distance between the vertical sections is 1 m. The temperature-measuring conduits 201 and 202 are welded to the points where they contact the rebar of the underground continuous wall.

[0069] Furthermore, the three temperature measuring points 203 on each temperature measuring conduit 201 are respectively arranged in the middle of the wall and 1000 mm away from the bottom of the underground continuous wall in the vertical direction (such as Figure 5 Middle height h1) and 2000mm from the bottom of the crown beam (such as Figure 5 Medium height h2) are arranged horizontally in the middle of the wall, 100mm from one edge, and 1000mm from one edge.

[0070] Furthermore, a control observation hole is provided on one side of the diaphragm wall in the foundation pit. A soil temperature measurement conduit is installed in the control observation hole, and a soil temperature measurement point 204 is arranged on the conduit for observing the soil temperature during the same period. The observation hole is drilled using a geological drill or anchor drilling rig, and the soil temperature measurement conduit is arranged. The length of the soil temperature measurement conduit is consistent with the depth of the underground diaphragm wall, and the temperature measurement point on the soil temperature measurement conduit is at the same height as the temperature measurement point on the underground diaphragm wall.

[0071] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for measuring temperature of large-volume concrete in underground continuous wall support, characterized by: The steps include: S1. Select underground continuous wall monitoring samples and design temperature measuring tubes and temperature measuring condenser tubes; S2. Layout of temperature measurement points; S3. Install the temperature measuring tube, temperature measuring condenser tube and temperature measuring wire; S4. pouring concrete and measuring the temperature of large-volume concrete to obtain temperature data; S5. Analyze the temperature data and, based on the analysis results, determine the impact of the temperature difference between the inside and outside of the permanent support mass concrete on concrete cracks; Among them, in step S1, an underground continuous wall monitoring sample is selected, and temperature measuring tubes and condenser tubes are designed, including: three underground continuous walls of different heights are selected as monitoring samples, three groups of temperature measuring tubes are arranged on the left, middle and right sides of each underground continuous wall, and three tubes are arranged in each group. The bottom of the temperature measuring tube is flush with the bottom of the underground continuous wall, the top is 1m above the ground, and the bottom end of the temperature measuring tube is sealed. Three temperature measuring wires of different lengths are arranged in each temperature measuring tube. A group of "J"-shaped temperature measuring condenser tubes are set on the front and back sides of each underground continuous wall, and one end of the temperature measuring condenser tubes on the front and back sides are connected. The distance between the horizontal pipe sections in the "J"-shaped temperature measuring condenser tubes is 2m, and the distance between the vertical pipe sections is 1m. The temperature measuring condenser tubes are welded and connected to the steel bars of the underground continuous wall.

2. The temperature measurement method for underground continuous wall supporting large volume concrete according to claim 1 is characterized in that: In step S2, the temperature measuring points are arranged, including: three temperature measuring points are set on each temperature measuring tube, and the tube temperature measuring points are arranged in the middle of the wall, 1000mm from the bottom of the underground continuous wall, and 2000mm from the bottom of the crown beam in the vertical direction; in the middle of the wall, 100mm from one side edge, and 1000mm from one side edge in the horizontal direction, and a control observation hole is set in the foundation pit as a soil temperature measuring point for observing the soil temperature during the same period.

3. The temperature measurement method for underground continuous wall supporting large volume concrete according to claim 2, characterized in that: In step S3, installing a temperature measuring conduit, a temperature measuring condenser tube, and a temperature measuring wire includes: S31. Mark the lengths of the temperature measuring wires, with the marking positions corresponding to the three temperature measuring points on each temperature measuring catheter. S32. Installing the temperature measuring condenser tube during the production process of the steel cage; S33, lower the steel cage; S34. Install temperature measuring tubes and temperature measuring wires: Divide 9 temperature measuring tubes into three groups and install them horizontally in the middle of the wall, 100mm away from one side edge, and 1000mm away from one side edge. Three tubes in each group are spaced apart in the same vertical plane. The temperature measuring tubes are welded and fixed to the underground continuous wall steel bars they are in contact with. Install the temperature measuring wires. Fix the top end of the temperature measuring wires with a wire tie, and fix the bottom end to the bottom of the temperature measuring tubes with a nylon rope.

4. The temperature measurement method for underground continuous wall supporting large volume concrete according to claim 1, characterized in that: In step S4, concrete is poured and the temperature of the mass concrete is measured to obtain temperature data, including: pouring concrete through a grouting pipe, pouring cement slurry into the temperature measuring tube after pouring is completed, starting to measure the temperature of the cement slurry within 4 hours after the concrete pouring is completed, recording the temperature entering the mold, using a multi-channel temperature inspection instrument to perform uninterrupted temperature measurement, recording once at the same time interval, when the difference between the temperature of the mass concrete and the ambient temperature is less than 20°C, stopping the temperature measurement, and after the temperature measurement time period ends, exporting the saved data to form a temperature data list and a curve list.

5. The temperature measurement method for underground continuous wall supporting large volume concrete according to claim 4, characterized in that: In step S5, the temperature data is analyzed, including: Temperature change trend analysis: observe the temperature change curve of each temperature measuring point over time, and compare the temperature changes of temperature measuring points at different depths and horizontal positions; Temperature gradient analysis in thickness direction: Calculate the temperature difference between temperature measurement points at different depths to obtain the temperature gradient in thickness direction; Horizontal temperature gradient analysis: Analyze the temperature of temperature measuring points at different positions on the same horizontal plane to understand the temperature uniformity in the horizontal direction.

6. The temperature measurement method for underground continuous wall supporting large volume concrete according to claim 5, characterized in that: In step S5, based on the analysis results, the influence of the temperature difference between the inside and outside of the permanent support mass concrete on the concrete cracks is determined, including: Assess the risk of cracks: During the concrete heating stage, if the temperature gradient between the duct temperature measuring point near the surface and the duct temperature measuring point in the center is greater than 25°C / m, the risk of concrete cracks is assessed and temperature control measures are required. The condenser is activated and condensate is added. The condensate flow rate is controlled between 1.2 and 2 m / s, and the temperature difference between the condensate inlet and outlet is controlled between 5 and 10°C. During the condensate pouring process, always pay attention to the temperature changes at each temperature measuring point and whether the cooling rate of the concrete inside the underground continuous wall is controlled within 2°C / d. During the concrete hardening process, the soil temperature is monitored to 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, it indicates that the concrete dissipates heat slowly and the internal temperature is too high, increasing the risk of cracks. If the soil temperature changes smoothly, it indicates that the concrete dissipates heat normally, which is conducive to evaluating the stability of the temperature field inside the concrete.

7. The temperature measurement method for underground continuous wall supporting large volume concrete according to claim 6, characterized in that: Also includes: Evaluate the impact of durability and the effectiveness of temperature control measures: Durability impact: Analyze the impact of temperature changes on concrete durability. When the internal temperature of large-volume concrete exceeds 65°C and 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 actual measured temperature data with the temperature control target value, and evaluate the effectiveness of the temperature control measures. When the condensation water cooling measure is adopted, if the temperature difference at each temperature measuring point does not exceed the design requirement of 25°C, it indicates that the temperature control measures are effective; if the temperature control does not reach the expected target, then make targeted adjustment suggestions. Among them, if the temperature peak exceeds 65°C, increase the flow rate or density of the condenser pipe; if the cooling rate of the concrete inside the underground continuous wall is greater than 2°C / d, adjust the insulation measures.

8. The temperature measurement method for underground continuous wall supporting large volume concrete according to claim 3, characterized in that: The control observation hole is drilled with a geological drill or anchor drilling rig, and a soil temperature measuring tube is laid. The length of the soil temperature measuring tube is consistent with the depth of the underground continuous wall, the height of the temperature measuring point of the soil temperature measuring tube is consistent with the temperature measuring point of the underground continuous wall, and the soil temperature measuring tube is poured with cement slurry of the same medium.

9. A temperature measurement system for underground continuous wall support of large volume concrete, characterized by: include: Temperature measuring conduits (201), temperature measuring wires, and temperature measuring condenser tubes (202), three groups of temperature measuring conduits (201) are respectively arranged horizontally on the left, middle, and right sides of each underground continuous wall (200), and each group is symmetrically provided with three temperature measuring conduits (201), and the three temperature measuring conduits (201) are respectively located near the front side, the middle, and the rear side of the underground continuous wall. The bottom of the temperature measuring conduits (201) is flush with the bottom of the underground continuous wall, and the top extends above the ground. Three temperature measuring points (203) are arranged vertically on each temperature measuring conduit (201). Each temperature measuring conduit ( Three temperature measuring wires of 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) respectively correspond to the three temperature measuring points (203) of each temperature measuring conduit (201). A group of "X"-shaped temperature measuring condensation tubes (202) are arranged on the front and back sides of each underground continuous wall (200), and the temperature measuring condensation tubes (202) on the front and back sides are connected at one end and extend upward to above the ground at the other end. A control observation hole is arranged on one side of the underground continuous wall in the foundation pit, and a soil temperature measuring conduit is arranged in the control observation hole, and soil temperature measuring points (204) are arranged on the soil temperature measuring conduit.

Images