A device and method for simulating the fluidity test of concrete

Abstract

The purpose of the present invention is to provide a device and a testing method for simulating the fluidity of concrete, belonging to the technical field of cofferdam bottom sealing construction. It includes a simulation test tank, in which a soil sample layer at the location to be sealed at the bottom is laid, and a water sample at the location to be sealed at the bottom is provided. The edge of the simulation test tank along the length direction is provided with scales, with the center position of the simulation test tank as scale 0, and extending to both sides in units of 1 m in sequence. A steel casing is provided at the 1 m scale position on one side of the center position of the simulation test tank, and two steel plates are provided along the width direction of the simulation test tank on the other side. Two steel pedals are provided between the two steel plates along the length direction of the simulation test tank, and a 0.1 m gap is left between the two steel pedals. A number of concrete flow radius indicators are provided in the gap. By using the present invention, the fluidity of concrete can be effectively tested under similar working conditions before the bottom sealing concrete is poured, ensuring controllability during the construction process and guaranteeing the smooth bottom sealing of the cofferdam.

Description

Technical Field

[0001] The present invention belongs to the technical field of cofferdam bottom sealing construction, and particularly relates to a device and a method for simulating and testing the fluidity of concrete. Background Art

[0002] During the construction of a double-wall steel cofferdam, the underwater pouring of the bottom-sealing concrete is a key process that determines the success or failure of the cofferdam construction, and its importance is self-evident. According to the required flow range of the concrete during the bottom sealing of the cofferdam, the concrete mix design is carried out. In traditional construction, generally, after the concrete mix is completed through tests, the concrete is directly produced and poured during the bottom sealing of the cofferdam, which often cannot ensure that the performance of the bottom-sealing concrete meets the actual requirements during construction. Therefore, the underwater performance test of the bottom-sealing concrete under similar conditions before pouring is an effective guarantee to ensure that the fluidity of the concrete can meet the requirements during the bottom-sealing pouring of the cofferdam. Summary of the Invention

[0003] The purpose of the present invention is to provide a device and a method for simulating and testing the fluidity of concrete, and to conduct the underwater performance test of the bottom-sealing concrete under similar conditions before pouring.

[0004] The present invention adopts the following technical solutions:

[0005] A device for simulating and testing the fluidity of concrete includes a simulation test tank. A soil sample layer at the location to be bottom-sealed is laid in the simulation test tank, and a water sample at the location to be bottom-sealed is provided. Scales are provided at the edges of the simulation test tank along the length direction. With the center position of the simulation test tank as scale 0 and in units of 1 m, it extends successively to both sides. A steel casing is provided at the 1 m scale position on one side of the center position of the simulation test tank. A groove is provided at the bottom on the other side of the center position of the simulation test tank (1). An acoustic wave probe (11) for detecting concrete is provided in the groove. One end of the acoustic wave probe (11) is connected to a monitor (13) through a signal line (12). The monitor (13) is located outside the simulation test tank (1). On the side of the simulation test tank (1) where the acoustic wave probe (11) is provided, two steel plates are provided along the width direction of the simulation test tank. Two steel pedals are provided along the length direction of the simulation test tank between the two steel plates. A 0.1 m gap is left between the two steel pedals, and several concrete flow radius indicators are provided in the gap.

[0006] Further, the cross-section of the simulation test tank is trapezoidal, with a length of 18 m, an upper mouth width of 4 m, a lower mouth width of 2.5 m, and a depth of 1 m.

[0007] Further, a waterproof rain cloth is laid at the bottom of the simulation test tank.

[0008] Further, several support rods are provided at the bottom of the steel plates.

[0009] Furthermore, the support rods are arranged at equal intervals, with a spacing of 20 cm.

[0010] Furthermore, the scales extend to 9m on both sides, and the steel plates are located at the positions of 1m and 7m on the scales respectively.

[0011] Furthermore, the flow radius indicators are located at positions with scales of 4m, 5m, 6m, and 8m respectively.

[0012] Furthermore, the flow radius indicator includes an indicator rod and a spoiler, the spoiler is located at the bottom of the indicator rod and vertically connected to the indicator rod, the spoiler is located in the simulation test tank, and the spoiler is perpendicular to the length direction of the simulation test tank.

[0013] Furthermore, the simulation test device also includes a feeding funnel, and the center of the feeding funnel is located at the center position of the simulation test tank, that is, the position where the scale is 0.

[0014] A concrete fluidity simulation test method comprises the following steps:

[0015] The first step is to simulate the layout of the test tank:

[0016] Select the river beach test site to be constructed, lay out a simulated test trough with a length of 18m, an upper width of 4m, a lower width of 2.5m, and a depth of 1m. After excavating the pit, lay a waterproof tarpaulin as a base, lay the test site stratum soil sample and river water in the simulated test trough, set scales on the edge of the simulated test trough, set the center of the simulated test trough as the starting point, i.e. scale 0, and extend to both sides in sequence with 1m as the subtotal unit;

[0017] Step 2: Concrete performance indicators:

[0018] The bottom concrete was tested and the initial slump was 200mm, the initial expansion was 550mm, the two-hour expansion was 510mm, the initial setting time was 21h, and the 7-day compressive strength was 27.9MPa, which was 90% greater than the design strength;

[0019] The third step is to dig a trench of 8m in length, 0.2m in width and 0.2m in depth at the bottom of the simulation test tank, and put an acoustic wave probe for detecting concrete into it. One end of the acoustic wave probe is connected to a monitor through a signal line, and the monitor is located outside the simulation test tank.

[0020] Step 4: Test platform layout:

[0021] A single operating platform uses 5 pieces of I20b with a length of 6m as supports, which are placed in parallel at an interval of 20cm and welded with a 6×1×0.01m steel plate on it as the operating platform. One 1.5m long φ630 steel pipe is placed at the 1m scale position on one side of the center of the simulated test tank to simulate the steel casing of the pile foundation inside the cofferdam. Two operating platforms are placed at the 1m and 7m positions on the other side. Two 6×0.2×0.05m steel tread plates are laid on the operating platforms, with a 0.1m wide area left empty in the middle. Inside this area, concrete flow radius indicators are placed at the 4m, 5m, 6m, and 8m scales;

[0022] In the fifth step, the crane lowers the funnel until its bottom touches the bottom and then lifts it by 0.2m. The bottom-sealing concrete is transported to the test site by a concrete mixer truck. After the funnel ball valve is in place, concrete is pumped. After filling 0.8m 3 of concrete, the crane lifts the ball valve, and the pump truck continuously pumps. Measure the height of the concrete surface at the lower opening of the funnel at this time, record it and compare the measurements at intervals. Observe the state of the concrete flow indicator. If it topples, it means the concrete has flowed to the current position. When the height of the concrete surface near the funnel suddenly increases or it is difficult to discharge the concrete, stop pumping. Coarsely read the flow radius range according to the observation mark. When the concrete stops flowing, the signal wire connected to the monitor at the rear end can be pulled. Record from the place where there is a concrete signal until the signal disappears. The instrument can accurately display the length of the area covered by the concrete.

[0023] The beneficial effects of the present invention are as follows:

[0024] By using the present invention, the fluidity of the concrete can be effectively tested under similar operating conditions before pouring the bottom-sealing concrete, ensuring controllability during the construction process and guaranteeing the smooth bottom-sealing of the cofferdam. Brief Description of the Drawings

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

[0026] Figure 2 is a schematic cross-sectional diagram of the concrete test tank;

[0027] Figure 3 is a schematic front view structural diagram of the flow radius indicator;

[0028] Figure 4 is a schematic side view structural diagram of the flow radius indicator;

[0029] Figure 5 is Figure 1 a partial enlarged view of;

[0030] Wherein: 1 - simulation test tank; 2 - steel casing; 3 - steel plate; 4 - steel pedal; 5 - flow radius indicator; 6 - indicator rod; 7 - flow blocker; 8 - feeding hopper; 9 - crane; 10 - concrete mixer truck; 11 - sonic probe; 12 - signal line; 13 - monitor. Specific implementation manner

[0031] In combination with the attached drawings, the present invention will be further described.

[0032] As shown in the figure, a device for simulating the fluidity of concrete includes a simulation test tank 1. A soil sample layer at the construction site to be sealed at the bottom is laid in the simulation test tank 1, and a water sample at the construction site to be sealed at the bottom is provided. Scales are provided at the edges of the simulation test tank 1 along the length direction. The scales take the center position of the simulation test tank 1 as scale 0 and extend to both sides in units of 1 m. A steel casing 2 is provided at the 1 m scale position on one side of the center position of the simulation test tank 1. A groove is provided at the bottom on the other side of the center position of the simulation test tank 1. A sonic probe 11 for detecting concrete is provided in the groove. One end of the sonic probe 11 is connected to a monitor 13 through a signal line 12. The monitor 13 is located outside the simulation test tank 1. On the side of the simulation test tank 1 where the sonic probe 11 is provided, two steel plates 3 are provided along the width direction of the simulation test tank 1. Two steel pedals 4 are provided between the two steel plates 3 along the length direction of the simulation test tank 1. A gap of 0.1 m is left between the two steel pedals 4, and a number of concrete flow radius indicators 5 are provided in the gap.

[0033] The flow radius indicator 5 includes an indicator rod 6 and a flow blocker 7. The flow blocker 7 is located at the bottom of the indicator rod 6 and is perpendicularly connected to the indicator rod 6. The flow blocker 7 is located in the simulation test tank 1 and is perpendicular to the length direction of the simulation test tank 1.

[0034] The usage method of the present invention is as follows:

[0035] 1. Site location: The test site is set on the beach of the Huaihe River Special Bridge (south bank of the Huaihe River).

[0036] 2. Dimensions and layout of the test tank: The length is 18 m, the upper opening width is 4 m, the lower opening width is 2.5 m, and the depth is 1 m. Since the initial setting time of the underwater concrete is relatively long and it needs to be in an underwater working condition, and at the same time to prevent the test concrete from polluting the beach site, a waterproof tarpaulin is laid at the bottom after excavating the pit. The bottom elevation of the cofferdam bottom seal is -6.77 m, and the top elevation of the bottom seal is -3.27 m. According to the geological conditions of the previous pile foundation construction, the bottom seal area is in the silty sand layer. In this test, the real working condition of the bottom seal concrete flow needs to be simulated. Therefore, samples are taken from the silty sand stratum at the Huaihe River elevation of -6.7 m, laid 0.2 m thick at the bottom of the tank, and 0.6 m of Huaihe River water is injected.

[0037] 3. Embedding of concrete monitor: Dig a groove at the bottom with a length of 8 m, a width of 0.2 m, and a depth of 0.2 m, and place the concrete acoustic wave probe.

[0038] 4. Concrete performance indicators: Conduct trial mixing of the bottom-sealing concrete. The initial slump is 200 mm, the initial spread is 550 mm, the spread after two hours is 510 mm, the initial setting time is 21 h, and the 7-day compressive strength is 27.9 MPa, which is greater than 90% of the design strength.

[0039] 5. Test platform: Use 5 pieces of 6 m I20b as supports for a single operating platform. Place them in parallel at a spacing of 20 cm and weld 6×1×0.01 m diamond-patterned steel plates on them. Make scale marks at the edge of the test tank, with 1 m as the sub-unit. Since the flow radius of the bottom-sealing concrete needs to reach 8 m, set the center position of the test tank as the starting point, i.e., scale 0, and extend to 9 m on both sides in turn. Place 1 piece of 1.5 m φ630 steel pipe at the 1 m scale position on one side to simulate the steel casing of the pile foundation inside the cofferdam. Place two operating platforms at the 1 m and 7 m positions on the other side. Lay two 6×0.2×0.05 m steel tread plates on the operating platforms, leaving a 0.1 m wide space in the middle. Place the concrete flow radius indicator marks at the 4 m, 5 m, 6 m, and 8 m scales in this area. The flow radius indicator mark consists of an indicator rod and a flow-blocking plate. The indicator rod is a 1 m long φ40 PVC pipe, and the flow-blocking plate is a 0.2×0.1×0.012 m bamboo plywood.

[0040] Lower the hopper with a crane until its bottom touches the bottom and then lift it by 0.2 m. The bottom-sealing concrete is transported to the test site by a concrete mixer truck mixed at the 1# batching plant of this project. After the hopper ball valve is in place, pump the concrete. When it is filled with 0.8 m 3 of concrete, the crane lifts the ball valve, and the pump truck continues to pump. The test personnel measure the height of the concrete surface at the bottom of the hopper at this time, make records and compare the measurements at intervals, and observe the state of the concrete flow indicator mark. If it topples, it means that the concrete has flowed to the current position. Stop pumping when the height of the concrete surface near the hopper suddenly increases or it is difficult to feed the concrete. Coarsely read the flow radius range according to the observation mark. When the concrete stops flowing, the signal wire connected to the monitor at the rear end can be pulled. Record from the place where there is a concrete signal until the signal disappears. The instrument can accurately display the length of the area covered by the concrete.

Claims

1. A simulation test device for the fluidity of concrete, characterized in that: It includes a simulation test tank (1). Inside the simulation test tank (1), a soil sample layer at the construction site to be sealed at the bottom is laid, and a water sample at the construction site to be sealed at the bottom is provided. The edge of the simulation test tank (1) along the length direction is provided with scales. The scales take the central position of the simulation test tank (1) as scale 0, and extend to both sides in units of 1 m successively. A steel casing (2) is provided at the 1 m scale position on one side of the central position of the simulation test tank (1). A groove is provided at the bottom on the other side of the central position of the simulation test tank (1). An acoustic wave probe (11) for detecting concrete is provided in the groove. One end of the acoustic wave probe (11) is connected to a monitor (13) through a signal line (12). The monitor (13) is located outside the simulation test tank (1). On the side of the simulation test tank (1) where the acoustic wave probe (11) is provided, two steel plates (3) are arranged along the width direction of the simulation test tank (1). Two steel pedals (4) are arranged along the length direction of the simulation test tank (1) between the two steel plates (3). A gap of 0.1 m is left between the two steel pedals (4). A number of concrete flow radius indicating marks (5) are provided in the gap.

2. The concrete fluidity simulation test device according to claim 1, characterized in that: The cross-section of the simulation test tank (1) is trapezoidal, with a length of 18 m, an upper opening width of 4 m, a lower opening width of 2.5 m, and a depth of 1 m.

3. The concrete fluidity simulation test device according to claim 2, characterized in that: A waterproof tarpaulin is laid at the bottom of the simulation test tank (1).

4. The concrete fluidity simulation test device according to claim 3, wherein: A number of support rods are provided at the bottom of the steel plate (3).

5. The concrete fluidity simulation test device according to claim 4, characterized in that: The support rods are arranged at equal intervals, and the interval is 20 cm.

6. The concrete fluidity simulation test device according to claim 5, wherein: The scales extend to 9 m on both sides respectively. The steel plates (3) are respectively located at the scale positions of 1 m and 7 m.

7. The concrete fluidity simulation test device according to claim 6, characterized in that: The flow radius indicating marks (5) are respectively located at the scale positions of 4 m, 5 m, 6 m, and 8 m.

8. A concrete fluidity simulation test device according to claim 7, characterized in that: The flow radius indicating mark (5) includes an indicating rod (6) and a flow blocking plate (7). The flow blocking plate (7) is located at the bottom of the indicating rod (6) and is perpendicularly connected to the indicating rod (6). The flow blocking plate (7) is located inside the simulation test tank (1), and the flow blocking plate (7) is perpendicular to the length direction of the simulation test tank (1).

9. The concrete fluidity simulation test device according to claim 8, wherein: The simulation test device further includes a feeding funnel (8). The center of the feeding funnel (8) is located at the central position of the simulation test tank (1), that is, at the scale position of 0.

10. A testing method using the concrete fluidity simulation testing device according to any one of claims 1-9, characterized in that: It includes the following steps: The first step, the layout of the simulation test tank: Select a test site on the river beach to be constructed. Lay out a simulation test tank with a length of 18 m, an upper opening width of 4 m, a lower opening width of 2.5 m, and a depth of 1 m. After excavating the pit, lay a waterproof tarpaulin at the bottom. Lay the formation soil sample and river water of the test site in the simulation test tank. Set scales on the edge of the simulation test tank. Take the central position of the simulation test tank as the starting point, that is, scale 0, and extend to both sides successively in units of 1 m. The second step, the performance index of concrete: Conduct trial mixing of the bottom-sealing concrete. The initial slump is 200 mm, the initial spread is 550 mm, the spread after two hours is 510 mm, the initial setting time is 21 h, and the 7-day compressive strength is 27.9 MPa, which is greater than 90% of the design strength. The third step, dig a groove with a length of 8 m, a width of 0.2 m, and a depth of 0.2 m at the bottom of the simulation test tank, and place an acoustic wave probe for detecting concrete. One end of the acoustic wave probe is connected to a monitor through a signal line. The monitor is located outside the simulation test tank. Step 4, test platform arrangement: A single operating platform is supported by 5 pieces of 6m I20b steel, arranged in parallel at a spacing of 20cm and welded with 6×1×0.01m steel plates on top as the operating platform. One 1.5m φ630 steel pipe is placed at the 1m scale position on one side of the center of the simulated test tank to simulate the steel casing of the pile foundation inside the cofferdam. Two operating platforms are placed at the 1m and 7m positions on the other side. Two 6×0.2×0.05m steel tread plates are laid on the operating platforms, with a 0.1m wide area spaced in the middle. Inside this area, concrete flow radius indicators are placed at the 4m, 5m, 6m, and 8m scales; Step 5: Lower the hopper with the crane. After its bottom touches the ground, lift it by 0.2 m. The concrete for sealing the bottom is transported to the test site by a concrete mixer truck. After the hopper ball valve is in place, pump the concrete. Wait until it is filled to 0.8 m 3 After the concrete is filled, lift the ball valve with the crane, and the pump truck continuously pumps the concrete. Measure the height of the concrete surface at the lower opening of the hopper at this time, make a record, and compare the measurements at intervals. Observe the status of the concrete flow indicator. If it topples, it means the concrete has flowed to the current position. When the height of the concrete surface near the hopper suddenly increases or the concrete feeding is difficult, stop pumping. According to the observation mark, roughly read the flow radius range. When the concrete stops flowing, the signal wire connected to the monitor at the rear end can be pulled. Record from the place where there is a concrete signal until the signal disappears. The instrument can accurately display the length of the area covered by the concrete.

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