Steel casing cast-in-place pile concrete height measuring instrument and steel casing cast-in-place pile concrete construction method

Abstract

The invention discloses a steel casing cast-in-place pile concrete height measuring instrument and a steel casing cast-in-place pile concrete construction method, and relates to the technical field of measuring instruments.The steel casing cast-in-place pile concrete height measuring instrument comprises a main pulley, an observation cable and a measuring cable, and the main pulley is used for being arranged at the top of a steel casing; one end of the observation cable is connected with a plumb bob, and the observation cable is wound on the main pulley in the first circumferential direction by taking the end connected with the plumb bob as a reference; one end of the measuring cable is connected with a floating ball, and the measuring cable is wound on the main pulley along a second circumferential direction by taking the end connected with the floating ball as a reference; the first circumferential direction and the second circumferential direction are opposite, and the floating ball is used for being placed in the steel casing; the plumb bob is lighter than the floating ball, and the density of the floating ball is smaller than that of concrete; in the using state, the plumb bob is located on the outer side of the steel casing, and the floating ball floats on concrete on the inner side of the steel casing under the action of buoyancy. The method is simple to operate, high in measurement speed and high in safety.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring instruments, and particularly relates to a measuring instrument for the height of concrete in a steel casing cast-in-place pile and a construction method for the concrete construction of a steel casing cast-in-place pile. Background Art

[0002] Bored cast-in-place piles are extremely common in the bridge construction of current highways, railways, and municipal engineering. When bored cast-in-place piles are constructed in soft geological conditions such as loose sand layers, fine angular gravel layers, quicksand layers, thick silt layers, and karst landforms, it is difficult to ensure the stability of the hole wall with mud slurry support, so the full casing construction technology is adopted to form the hole. During the process of pouring pile foundation concrete, due to the limitation of the initial setting time of concrete and the reason of friction, the higher the pouring height of the concrete surface, the greater the pulling resistance to the steel casing. Therefore, the steel casing has a process of being pulled up with the pouring height. During the process of pulling out the steel casing, it is necessary to ensure that the bottom of the steel casing does not exceed the concrete top surface. This requires construction technicians to always master the pouring height of the concrete surface, so as to accurately perform the pulling-up operation on the steel casing. The conventional method for measuring the pouring elevation of the concrete surface is to use a simple sounding rope for operation. After the steel casing is pulled out for a certain length, the worker needs to measure from the inner side above the steel casing. The operation is relatively cumbersome and the measuring speed is slow. Especially when the steel casing is being pulled out and is in a high-altitude state, the measurement is extremely inconvenient and the safety risk is also high. At the same time, the sounding rope is repeatedly lifted in the mud slurry and is easily contaminated by the mud slurry, which affects the reading. Summary of the Invention

[0003] The purpose of the present invention is to provide a measuring instrument for the height of concrete in a steel casing cast-in-place pile and a construction method for the concrete construction of a steel casing cast-in-place pile to solve the problems existing in the above-mentioned prior art, with simple operation, fast measuring speed, and high safety.

[0004] To achieve the above purpose, the present invention provides the following solutions: The present invention provides a measuring instrument for the height of concrete in a steel casing cast-in-place pile, including: A main pulley for being arranged on the top of the steel casing; An observation cable, one end of the observation cable is connected with a plumb bob. Taking the end connected with the plumb bob as a reference, the observation cable is wound around the main pulley along a first circumferential direction; A measurement cable, one end of the measurement cable is connected with a float. Taking the end connected with the float as a reference, the measurement cable is wound around the main pulley along a second circumferential direction; the first circumferential direction and the second circumferential direction are opposite directions, and the float is used to be placed inside the steel casing; the weight of the plumb bob is less than that of the float, and the density of the float is less than the density of the concrete; In the use state, the plumb bob is located outside the steel casing, and the float floats on the concrete inside the steel casing under the action of buoyancy.

[0005] Preferably, the main pulley is a double-groove pulley, the observation cable and the measurement cable are respectively two separate ropes, and the observation cable and the measurement cable are respectively wound in the two grooves of the main pulley.

[0006] Preferably, a scale is further included, and the scale is used to be arranged on the outer wall of the steel casing, and the scale is arranged vertically.

[0007] Preferably, a support frame is further included, the support frame is fixedly arranged on the top edge of the steel casing, and the main pulley is arranged on the support frame.

[0008] Preferably, a cantilever bracket and an auxiliary pulley are further included. One end of the cantilever bracket is fixedly connected to the support frame, and the other end extends towards the center of the cylindrical space where the steel casing is located. The auxiliary pulley is arranged at the end of the cantilever bracket far from the support frame, and the measurement cable is wound on the side of the auxiliary pulley far from the support frame.

[0009] Preferably, the floating ball is formed by pouring epoxy resin material and a counterweight.

[0010] Preferably, the density of the floating ball is between the concrete and the slurry inside the steel casing.

[0011] Preferably, the floating ball is a conical structure, its bottom diameter is 200 mm, and its density is 1.8 g / cm 3 -2.2 g / cm 3 .

[0012] Preferably, the measurement cable and the observation cable are steel ropes.

[0013] The present invention also provides a construction method for cast-in-place concrete of a steel casing bored pile, including: Determining the initial buried depth height of the steel casing: calculating the buried depth height h1 of the steel casing after the first batch of concrete is poured according to the volume of the first batch of concrete poured and the diameter of the pile foundation; Installing the height measuring instrument for cast-in-place concrete of the steel casing bored pile: installing the height measuring instrument for cast-in-place concrete of the steel casing bored pile and making the height where the plumb bob is located flush with the height at the h1 scale on the scale; Repeating the pouring step: pouring concrete into the steel casing and observing the change in the buried depth of the steel casing. When the set threshold is reached, the steel casing is lifted until the height where the plumb bob is located is flush with the height at the h1 scale on the scale, and then continue pouring until completion.

[0014] The present invention has achieved the following technical effects compared with the prior art: When the present invention is applied, the floating ball is placed inside the steel casing, and the plumb bob is placed outside the steel casing. Since the observation cable and the measurement cable are wound around the main pulley in opposite directions, when the floating ball changes with the height of the concrete inside the steel casing, it will drive the plumb bob outside the steel casing to move up and down through the rotation of the main pulley. Thus, the construction technicians can quickly measure the height change of the concrete surface inside the steel casing outside the steel casing, which is beneficial for the construction technicians to calculate the height difference between the concrete surface inside the steel casing and the bottom of the steel casing. The invention has the characteristics of simple installation and operation, fast speed and high accuracy in measuring the concrete height, and can dynamically display the height change of the concrete surface without manual continuous measurement, thereby guiding the lifting height of the steel casing.

[0015] Further, when the floating ball is flush with the bottom of the steel casing, the plumb bob is flush with the 0 scale line of the scale. This enables the scale indicated by the plumb bob on the scale to be the height difference between the top surface of the concrete inside the steel casing and the bottom surface of the steel casing, thereby more intuitively and dynamically displaying the position of the top surface of the concrete inside the steel casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is a schematic diagram of the installation of the concrete height measuring instrument for steel casing cast-in-place piles on the steel casing during application.

[0018] Figure 2 is Figure 1 The side view of the concrete height measuring instrument for steel casing cast-in-place piles in.

[0019] Figure 3 is Figure 1 The side view of the main pulley and the support frame in.

[0020] Figure 4 is Figure 3 The front view of.

[0021] Figure 5 It is a schematic diagram of the snap spring.

[0022] Figure 6 It is a schematic diagram of the pin shaft.

[0023] Figure 7 It is a schematic diagram of the scale.

[0024] In the figure: 1 - Main pulley; 2 - Support frame; 3 - Pin shaft; 4 - Cantilever bracket; 5 - Measuring cable; 6 - Observation cable; 7 - Floating ball.

[0025] 101 - Measuring cable installation groove; 102 - Observation cable installation groove; 103 - Middle partition; 104 - Side partitions; 105 - Bearing.

[0026] 201 - Support plate.

[0027] 301 - Clip spring installation groove; 302 - Screw hole; 303 - Hexagon head bolt; 304 - Base plate; 305 - Clip spring.

[0028] 401 - Auxiliary pulley; 403 - Limit frame.

[0029] 601 - Plumb bob.

[0030] 100 - Steel casing. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] The purpose of the present invention is to provide a measuring instrument for the height of concrete in a steel casing cast-in-place pile and a construction method for the concrete construction of a steel casing cast-in-place pile, so as to solve the problems existing in the prior art. The present invention is simple to operate, has a fast measurement speed and high safety.

[0033] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0034] First, some technical terms involved in the embodiments of the present application will be introduced.

[0035] Concrete means concrete.

[0036] Next, in conjunction with Figures 1 to 7 , the embodiments of the present invention will be described.

[0037] The present invention provides a measuring instrument for the height of concrete in a steel casing cast-in-place pile, comprising: a main pulley 1, an observation cable 6 and a measurement cable 5. The main pulley 1 is used to be arranged at the top of the steel casing 100. One end of the observation cable 6 is connected with a plumb bob 601. Taking the end connected with the plumb bob 601 as a reference, the observation cable 6 is wound around the main pulley 1 along a first circumferential direction. One end of the measurement cable 5 is connected with a floating ball 7. Taking the end connected with the floating ball 7 as a reference, the measurement cable 5 is wound around the main pulley 1 along a second circumferential direction. The first circumferential direction and the second circumferential direction are opposite directions. The floating ball 7 is used to be placed inside the steel casing 100. The weight of the plumb bob 601 is less than that of the floating ball 7, and the density of the floating ball 7 is less than the density of the concrete. In the use state, the plumb bob 601 is located outside the steel casing 100, and the floating ball 7 floats on the concrete inside the steel casing 100 under the action of buoyancy. The floating ball 7 can rise as the concrete inside the steel casing 100 increases.

[0038] When the present invention is applied, the floating ball 7 is placed inside the steel casing 100, and the plumb bob 601 is placed outside the steel casing 100. Since the observation cable 6 and the measurement cable 5 are wound around the main pulley 1 in opposite directions, when the floating ball 7 changes with the height of the concrete inside the steel casing 100, it will drive the plumb bob 601 outside the steel casing 100 to move up and down through the rotation of the main pulley 1. Furthermore, construction technicians can quickly measure the height change of the concrete surface inside the steel casing 100 outside the steel casing 100, which is beneficial for construction technicians to calculate the height difference between the concrete surface inside the steel casing 100 and the bottom of the steel casing 100. The invention has the characteristics of simple installation and operation, fast measurement speed and high accuracy of the concrete height, and can dynamically display the height change of the concrete surface without manual continuous measurement, thereby guiding the lifting height of the steel casing 100.

[0039] In some embodiments, the main pulley 1 is a double-groove pulley, and the observation cable 6 and the measurement cable 5 are respectively two separate ropes, and the observation cable 6 and the measurement cable 5 are respectively wound in two grooves of the main pulley 1.

[0040] In this embodiment, two ropes are provided as the observation cable 6 and the measurement cable 5, and the observation cable 6 and the measurement cable 5 are separately arranged. This eliminates the need for the observation cable 6 and the measurement cable 5 to be wound orderly along a certain specific direction when wound around the groove of the main pulley 1. It can be understood that in some embodiments, a single-groove pulley can also be used, and the observation cable 6 and the measurement cable 5 are formed on one rope. This scheme requires this one rope to be wound orderly along a certain direction in the groove, which requires a wider groove to implement the above scheme.

[0041] In some embodiments, the embodiment of the present invention further includes a scale, and the scale is used to be arranged on the outer wall of the steel casing 100, and the scale is arranged vertically.

[0042] In this embodiment, the scale is used as a reference standard to enable construction technicians to more accurately know the height of the concrete inside the steel casing 100. It is understandable that when setting the position of the scale, it should be set as close as possible to the plumb bob 601, which facilitates construction technicians to intuitively view the height of the concrete surface inside the steel casing 100.

[0043] In the actual application scenario, when pouring concrete into the steel casing 100, the floating ball 7 rises with the concrete surface. Due to gravity balance, the plumb bob 601 at the end of the observation cable 6 descends simultaneously. By checking the height marks marked on the outside of the steel casing 100 by the plumb bob 601, the change in the burial depth of the steel casing 100 can be viewed in real time. After pouring a certain height, the construction technician lifts the steel casing 100. The height of the inner floating ball 7 remains unchanged, and the plumb bob 601 rises immediately. The burial depth of the steel casing 100 is reflected on the scale line where the counterweight is located in real time, realizing precise control of the lifting height of the steel casing 100.

[0044] The material of the scale is not limited.

[0045] In some embodiments, the embodiment of the present invention further includes a support frame 2. The support frame 2 is fixedly arranged on the top edge of the steel casing 100, and the main pulley 1 is arranged on the support frame 2.

[0046] This embodiment provides a fixing method for the main pulley 1.

[0047] Specifically, there are various structural forms of the support frame 2, as long as it can serve the purpose of supporting the main pulley 1.

[0048] In some examples, the support frame 2 includes two support plates 201. The bottom of the two support plates 201 is provided with a clamping groove for clamping on the top edge of the steel casing 100. The steel casing 100 and the bottom of the support plate 201 are connected by means of bolts, clamping or welding. The two support plates 201 are arranged in parallel with a gap. At a position near the top of the two support plates 201, there are shaft holes or grooves for supporting the pin shaft 3. Both ends of the pin shaft 3 are fixedly inserted into the shaft holes or grooves. A central hole is provided in the middle of the main pulley 1, and a bearing 105 is arranged in the central hole. The bearing 105 is sleeved on the pin shaft 3. A circlip mounting groove 301 is respectively opened at positions near both ends of the pin shaft 3. The pin shaft 3 passes through the central hole of the main pulley 1, and a circlip 305 is arranged in the circlip mounting groove 301. The circlip 305 is used to limit the position of the bearing 105 and the main pulley 1 on the pin shaft 3.

[0049] The above example is only a specific embodiment. In some examples, the bearing 105 may not be provided, and the pin shaft 3 and the support plate 201 may be made into a rotating fit structure, and then the main pulley 1 is fixedly or rotatably arranged on the pin shaft 3.

[0050] In some embodiments, the embodiments of the present invention further include a cantilever bracket 4 and an auxiliary pulley 401. One end of the cantilever bracket 4 is fixedly connected to the support bracket 2, and the other end extends towards the center of the cylindrical space where the steel casing 100 is located. An auxiliary pulley 401 is provided at the end of the cantilever bracket 4 away from the support bracket 2, and the measuring cable 5 is wound around the side of the auxiliary pulley 401 away from the support bracket 2.

[0051] The auxiliary pulley 401 in this embodiment is used to change the direction of the measuring cable 5 so that the measuring cable 5 is located inside the steel reinforcement cage in the steel casing 100, avoiding interference between the measuring cable 5 and the steel reinforcement cage.

[0052] The cantilever bracket 4 may specifically adopt a double-steel bar structure. The two steel bars are arranged in parallel with a gap therebetween. One end of the two steel bars is fixedly connected to the support bracket 2, and the other end is connected with the auxiliary pulley 401. The steel bars are processed and manufactured from steel plates with a thickness of 10 mm.

[0053] In some embodiments, a limit frame 403 is provided at the end of the cantilever bracket 4 where the auxiliary pulley 401 is provided. The limit frame 403 is arranged to semi-surround the outside of the auxiliary pulley 401 and jointly encloses a measuring cable guide groove with the auxiliary pulley 401. The measuring cable guide groove is used for the measuring cable 5 to pass through, and the limit frame 403 is used to limit the position of the measuring cable 5 to prevent the measuring cable 5 from slipping out of the chute of the auxiliary pulley 401 due to some external factors during use.

[0054] In some embodiments, the floating ball 7 is formed by casting epoxy resin and a counterweight.

[0055] In this embodiment, it is made by casting epoxy resin and a counterweight; the density of the floating ball 7 is between that of the cement slurry (1.5 g / cm 3 3) and that of the concrete (2.4 g / cm 3 3), and its density is 1.8 g / cm 3 -2.2 g / cm 3 3, ensuring that it will not float on the cement slurry or sink into the concrete, making the measurement of the height of the concrete more accurate.

[0056] In some embodiments, the floating ball 7 has a conical structure with a bottom diameter of 200 mm, ensuring that it has a large enough contact area with the concrete surface.

[0057] In some embodiments, the measuring cable 5 and the observation cable 6 are steel ropes, preferably with a diameter of less than 2 mm.

[0058] In some embodiments, the scale of the scale increases sequentially from top to bottom, and the height difference between the floating ball 7 and the bottom surface of the steel casing 100 is the dimension indicated by the plumb bob 601 on the scale.

[0059] This embodiment enables the scale indicated by the plumb bob 601 on the scale to be the height difference between the top surface of the concrete in the steel casing 100 and the bottom surface of the steel casing 100, thereby more intuitively and dynamically displaying the position of the top surface of the concrete in the steel casing 100.

[0060] In some embodiments, the pin shaft 3 is 128 mm long and 40 mm in diameter. One 2-mm-wide and 2-mm-deep circlip mounting groove 301 is opened at a position 23 mm from each end of the pin shaft 3. It passes through the central hole of the main pulley 1 and is connected to the bearing 105 with a circlip 305. M6 deep 12-mm screw holes 302 are opened at the centers of both ends of the pin shaft 3, and are connected to the support plate 201 with hexagon head bolts 303 and backing plates 304. The hexagon bolt model is C-class M6×16. The backing plate 304 has a diameter of 70 mm and is made of 5-mm steel plate.

[0061] The main pulley 1 is constructed with a middle partition 103 and two side partitions 104 to form a mountain-shaped double-groove structure. The mountain-shaped double-groove structure includes a measuring cable installation groove 101 and an observation cable installation groove 102.

[0062] The outer diameter of the middle partition 103 is 180 mm, the outer diameter of the two side partitions 104 is 170 mm, the inner diameter of the central hole of the main pulley 1 is 68 mm, and bearings 105 are installed on both sides of the hole. The bearing 105 model is 16008-2Z.

[0063] In some embodiments, the plumb bob 601 is a cylinder structure and is connected to the observation cable 6 with bolts.

[0064] The present invention also provides a construction method for cast-in-place concrete piles in steel casings, including: Determine the initial buried depth height of the steel casing 100: Calculate the buried depth height h1 of the steel casing 100 after the first batch of concrete is poured according to the volume of the first batch of concrete poured and the diameter of the pile foundation. Install the height measuring instrument for cast-in-place concrete piles in steel casings: Install the height measuring instrument for cast-in-place concrete piles in steel casings and make the height where the plumb bob 601 is located flush with the h1 scale on the scale. Repeat the pouring steps: Pour concrete into the steel casing 100 and observe the change in the buried depth of the steel casing 100. When the set threshold is reached, lift the steel casing 100 until the height where the plumb bob 601 is located is flush with the h1 scale on the scale, and then continue pouring until completion.

[0065] Specifically: Step 1: Measure the density of concrete and mud.

[0066] After the pile foundation hole is completed, the density of the pre-poured concrete (ρ1) and the density of the mud (ρ2) are respectively tested by the on-site laboratory in advance.

[0067] Step 2: Make the float ball 7 and the plumb bob 601.

[0068] The float 7 is made according to the measured test data ρ1 and ρ2. The float 7 is made of adjustable density epoxy resin. Before making, the density (ρ3) range of the float 7 is determined. ρ3 should meet ρ1>ρ3>ρ2 to achieve gravity balance. Then, the epoxy resin is prepared in the customized mold. After it solidifies, the density of the float 7 is re-measured to ensure that the process requirements are met. The mass of the plumb ball 601 should be 1 / 3 of the mass of the float 7 to meet the requirements of straightening the measuring cable 5 and the observation cable 6.

[0069] The weight requirement of the plumb ball 601 should be equal to that of the straightened observation rope 6 (the observation rope 6 is made of a 2mm diameter steel rope, and the length is appropriately configured according to the length of the pile foundation).

[0070] Step 3: Bury the steel casing 100 and post the scale Use a crane and a vibrating hammer to accurately install the steel casing 100 to the bottom of the hole. Post a scale on the outer wall of the casing. The scale needs to be lifted with the casing and continue to be posted to meet observation requirements.

[0071] Step 4: Make the support frame 2, the main pulley 1 and the auxiliary pulley 401, etc.

[0072] The measuring cable 5 and the observation cable 6 are made of 2mm diameter steel ropes, and the length is appropriately configured according to the length of the pile foundation. The measuring cable 5 is installed in the measuring cable installation groove 101, passes through the auxiliary pulley 401 and is placed inside the steel casing 100, and the floating ball 7 is installed at the end; the observation cable 6 is installed in the observation cable installation groove 102 and built inside the steel casing 100, and the plumb ball 601 is installed at the end; the two cables are installed in reverse.

[0073] Step 5: pour the first batch of concrete, lower the float 7 to the concrete surface, and adjust the plumb ball 601 to the corresponding value.

[0074] Carry out the first batch of concrete pouring, and calculate the buried height h1 of the steel casing 100 after the first batch of concrete pouring according to the volume of the first batch of concrete pouring and the diameter of the pile foundation.

[0075] The measuring instrument is installed on the top surface of the steel casing 100 through the support frame 2, and the measuring cable 5 and the observation cable 6 are respectively placed on the inner and outer sides of the steel casing 100. A height scale is set on the steel casing 100, the measuring cable 5 is hung with a floating ball 7 and placed inside the steel casing 100 and lowered to the concrete surface, and the observation cable 6 is hung with a plumb ball 601 and placed outside the steel casing 100, and the plumb ball 601 is placed at the scale h1 position of the scale.

[0076] Step 6: Continue pouring pile foundation concrete The pile foundation concrete is poured using the conduit method. When the float 7 rises with the concrete surface, the plumb ball 601 at the end of the observation cable 6 drops. By checking the height mark of the plumb ball 601 on the outside of the steel casing 100, the buried depth change of the steel casing 100 can be checked in real time.

[0077] Step 7: Lift the steel casing 100 Observe the buried depth of the casing in real time through the corresponding scale of the plumb bob 601 and the observation cable 6. When the buried depth of the casing is greater than 4m, carry out the lifting operation on the steel casing 100. When the casing is lifted to a buried depth of 2m, continue to pour concrete, and repeat observing the scale → lifting the steel casing 100 → pouring concrete until the pile foundation pouring is completed and the steel casing 100 is completely pulled out.

[0078] The present invention has the following characteristics: (1) The steel casing cast-in-place pile concrete height measuring instrument provided by the present invention is easy to process, simple to install and operate, has the characteristics of fast measurement speed and high accuracy for controlling the lifting height of the steel casing 100 during the casting of cast-in-place pile concrete, and can effectively ensure the construction quality of the pile foundation.

[0079] (2) When using the conventional measuring rope to measure the concrete elevation, there is a great risk of falling. While using the automatic measuring instrument for the height of the concrete of the steel casing 100 cast-in-place pile, the concrete elevation can be measured outside the casing, which can effectively avoid the safety risks existing in the conventional method.

[0080] Process principle: Fix the steel casing cast-in-place pile concrete height measuring instrument on the upper edge of the pile foundation steel casing 100 through the support frame 2. In specific applications, under the action of the real-time changes of the floating ball 7, the plumb bob 601 and the concrete surface inside the steel casing 100, the main pulley 1 rotates in real time, and then the height of the plumb bob 601 changes, which can accurately measure the height change of the concrete surface through the scale outside the steel casing 100 and guide the lifting height of the steel casing 100.

[0081] The benefit analysis of the present invention is as follows; The steel casing cast-in-place pile concrete height measuring instrument provided by the present invention has the advantages of being easy to process, simple to install and operate. Compared with the conventional method of measuring the concrete elevation with a measuring rope, it has the advantages of high measurement accuracy and low safety risk. It effectively avoids the pile foundation quality defects caused by prematurely pulling out the steel casing 100 during the casting of pile foundation concrete. This method is safe, environmentally friendly and has good social benefits and practical value.

[0082] Specific examples are used in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A measuring instrument for the height of concrete in a cast-in-place pile with a steel casing, characterized in that: Including: A main pulley, which is used to be arranged at the top of the steel casing; An observation cable, one end of the observation cable is connected with a plumb bob. Taking the end connected with the plumb bob as a reference, the observation cable is wound around the main pulley along a first circumferential direction; A measurement cable, one end of the measurement cable is connected with a float. Taking the end connected with the float as a reference, the measurement cable is wound around the main pulley along a second circumferential direction; the first circumferential direction and the second circumferential direction are opposite directions, and the float is used to be placed inside the steel casing; the weight of the plumb bob is less than that of the float, and the density of the float is less than the density of the concrete; In the working state, the plumb bob is located outside the steel casing, and the float floats on the concrete inside the steel casing under the action of buoyancy.

2. The concrete height measuring instrument for the steel casing cast-in-place pile according to claim 1, characterized in that: The main pulley is a double-groove pulley, the observation cable and the measurement cable are respectively two separate ropes, and the observation cable and the measurement cable are respectively wound in the two grooves of the main pulley.

3. The concrete height measuring instrument for the steel casing cast-in-place pile according to claim 1, characterized in that: It further includes a scale, and the scale is used to be arranged on the outer wall of the steel casing, and the scale is arranged vertically.

4. The concrete height measuring instrument for steel casing cast-in-place pile according to claim 1, wherein: It further includes a support frame, the support frame is fixedly arranged at the top edge of the steel casing, and the main pulley is arranged on the support frame.

5. The concrete height measuring instrument for steel casing cast-in-place pile according to claim 4, wherein: It further includes a cantilever bracket and an auxiliary pulley. One end of the cantilever bracket is fixedly connected with the support frame, and the other end extends towards the center of the cylindrical space where the steel casing is located. The auxiliary pulley is arranged at the end of the cantilever bracket far away from the support frame, and the measurement cable is wound on the side of the auxiliary pulley far away from the support frame.

6. The concrete height measuring instrument for the steel casing cast-in-place pile according to claim 1, characterized in that: The float is formed by pouring epoxy resin material and a counterweight block.

7. The concrete height measuring instrument for steel casing cast-in-place pile according to claim 1, characterized in that: The density of the float is between the concrete and the mud inside the steel casing.

8. The concrete height measuring instrument for steel casing cast-in-place pile according to claim 1, characterized in that: The floating ball is in a conical structure, with a bottom diameter of 200 mm and a density ranging from 1.8 g / cm 3 - 2.2 g / cm 3 .

9. The concrete height measuring instrument for steel casing cast-in-place piles according to claim 1, characterized in that: The measurement cable and the observation cable are steel ropes.

10. A construction method for cast-in-place concrete pile with steel casing, characterized in that: Including: Determining the initial buried depth height of the steel casing: calculating the buried depth height h1 of the steel casing after the first batch of concrete pouring according to the pouring volume of the first batch of concrete and the diameter of the pile foundation; Installing the concrete height measuring instrument for the steel casing cast-in-place pile: installing the concrete height measuring instrument for the steel casing cast-in-place pile and making the height where the plumb bob is located flush with the height at the h1 scale on the scale; Repeating the pouring step: pouring concrete into the steel casing and observing the change of the buried depth of the steel casing. When the set threshold value is reached, the steel casing is lifted until the height where the plumb bob is located is flush with the height at the h1 scale on the scale, and then continue to pour until completion.

Images