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

Abstract

The present invention discloses a steel casing cast-in-place pile concrete height measuring instrument and a steel casing cast-in-place pile concrete construction method, relating 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. The main pulley is arranged on the top of the steel casing; one end of the observation cable is connected to a plumb bob, and the observation cable is wound around the main pulley along a first circumferential direction, with the end connected to the plumb bob as a reference; one end of the measuring cable is connected to a float, and the measuring cable is wound around the main pulley along a second circumferential direction, with the end connected to the float as a reference; the first circumferential direction and the second circumferential direction are opposite directions, and the float is arranged to be placed inside the steel casing; the plumb bob is lighter than the float, and the density of the float is lower than the density of concrete; in use, 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. The present invention is simple to operate, fast in measurement speed, and highly safe.

Description

Technical Field

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

[0002] Bored cast-in-place piles are now widely used in the construction of highways, railways, and bridges in municipal engineering projects. Cast-in-place piles are constructed in soft geological conditions such as loose sand layers, fine-angle gravel layers, quicksand layers, thick silt layers, and karst landforms. Mud wall protection is difficult to ensure the stability of the hole wall, so full casing construction technology is used to form holes. During the pouring of pile foundation concrete, due to the limitations of the initial setting time of concrete and friction, the higher the pouring height of the concrete surface, the greater the resistance to the steel casing to lifting. Therefore, the steel casing will rise with the pouring height. During the extraction process, the bottom of the steel casing must ensure that it does not exceed the top surface of the concrete. This requires construction technicians to always grasp the pouring height of the concrete surface so that they can accurately lift the steel casing. The conventional method of measuring the pouring elevation of the concrete surface is to use a simple measuring rope. After the steel casing is pulled out for a while, workers need to measure from the inside of the top of the steel casing. The operation is cumbersome and the measurement speed is slow. Especially when the steel casing is pulled out, it is at a high altitude, which makes the measurement extremely inconvenient and the safety risk is also high. At the same time, the measuring rope is repeatedly pulled in the mud, which is easily contaminated by the mud and affects the reading. Summary of the Invention

[0003] The purpose of the present invention is to provide a steel casing cast-in-place pile concrete height measuring instrument and a steel casing cast-in-place pile concrete construction method 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 object, the present invention provides the following solutions:

[0005] The present invention provides a steel casing cast-in-place pile concrete height measuring instrument, comprising:

[0006] A main pulley is used to be arranged on the top of the steel casing;

[0007] an observation rope, one end of which is connected to a plumb bob, and the observation rope is wound around the main pulley along a first circumferential direction with the end connected to the plumb bob as a reference;

[0008] a measuring rope, one end of which is connected to a float; the measuring rope is wound around the main pulley along a second circumferential direction, with the end connected to the float as a reference; the first circumferential direction and the second circumferential direction are opposite directions; the float is used to be placed in the steel casing; the weight of the plumb ball is less than that of the float, and the density of the float is less than that of concrete;

[0009] In use, the plumb ball is located outside the steel casing, and the floating ball floats on the concrete inside the steel casing under the action of buoyancy.

[0010] Preferably, the main pulley is a double-groove pulley, the observation rope and the measuring rope are two separate ropes, and the observation rope and the measuring rope are respectively wound in the two grooves of the main pulley.

[0011] Preferably, it further comprises a scale, which is used to be set on the outer wall of the steel casing, and the scale is set vertically.

[0012] Preferably, it further comprises a support frame, which is fixedly arranged on the top edge of the steel casing, and the main pulley is arranged on the support frame.

[0013] Preferably, it also includes a cantilever bracket and an auxiliary pulley, one end of the cantilever bracket is fixedly connected to the support frame, and the other end extends toward the center of the cylindrical space where the steel casing is located. The auxiliary pulley is provided at the end of the cantilever bracket away from the support frame, and the measuring rope is wound around the side of the auxiliary pulley away from the support frame.

[0014] Preferably, the float is made of epoxy resin and a counterweight.

[0015] Preferably, the density of the float ball is between that of the concrete and the mud inside the steel casing.

[0016] Preferably, the float is a conical structure with a bottom diameter of 200 mm and a density of 1.8 g / cm 3 -2.2g / cm 3 .

[0017] Preferably, the measuring rope and the observation rope are steel ropes.

[0018] The present invention also provides a steel casing cast-in-place pile concrete construction method, comprising:

[0019] Determine the initial buried depth of the steel casing: Calculate the buried depth h1 of the steel casing after the first batch of concrete pouring based on the volume of the first batch of concrete pouring and the pile foundation diameter;

[0020] Install the steel casing bored pile concrete height measuring instrument: Install the steel casing bored pile concrete height measuring instrument and make sure the height of the plumb ball is flush with the h1 scale on the scale;

[0021] Repeat the pouring steps: pour concrete into the steel casing and observe the changes in the buried depth of the steel casing. When the set threshold is reached, pull up the steel casing and bury it until the height of the plumb bob is flush with the height of the h1 scale on the scale, and then continue pouring until completion.

[0022] Compared with the prior art, the present invention has achieved the following technical effects:

[0023] When the present invention is used, the float is placed on the inner side of the steel casing and the plumb ball is placed on the outer side of the steel casing. Since the observation rope and the measuring rope are wound on the main pulley in opposite directions, when the float changes with the height of the concrete in the steel casing, the main pulley rotates to cause the plumb ball outside the steel casing to move up and down, so that construction technicians can quickly measure the height change of the concrete surface inside the steel casing outside the steel casing, which is beneficial for 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 concrete height measurement speed and high accuracy, and can dynamically display the height change of the concrete surface without manual continuous measurement, thereby guiding the height of the steel casing.

[0024] Furthermore, when the float is flush with the bottom of the steel casing, the plumb ball is flush with the 0 scale line of the scale. This allows the scale indicated by the plumb ball on the scale to be the height difference between the top surface of the concrete in 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 in the steel casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a schematic diagram of the steel casing cast-in-place pile concrete height measuring instrument when it is installed on the steel casing.

[0027] Figure 2 yes Figure 1 Side view of the Sinosteel casing cast-in-place pile concrete height measuring instrument.

[0028] Figure 3 yes Figure 1 Side view of the middle main pulley and support frame.

[0029] Figure 4 yes Figure 3 Front view of .

[0030] Figure 5 This is a schematic diagram of the spring clip.

[0031] Figure 6 This is a schematic diagram of the pin shaft.

[0032] Figure 7 It is a schematic diagram of a scale.

[0033] In the picture:

[0034] 1- Main pulley; 2- Support frame; 3- Pin shaft; 4- Cantilever bracket; 5- Measuring rope; 6- Observation rope; 7- Float.

[0035] 101- measuring cable installation slot; 102- observation cable installation slot; 103- middle partition; 104- both side partitions; 105- bearing.

[0036] 201-Support plate.

[0037] 301-reed plate mounting slot; 302-screw hole; 303-hexagonal head bolt; 304-pad; 305-reed plate.

[0038] 401- auxiliary pulley; 403- limit frame.

[0039] 601-Pendulum.

[0040] 100-Steel casing. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] The purpose of the present invention is to provide a steel casing cast-in-place pile concrete height measuring instrument and a steel casing cast-in-place pile concrete construction method to solve the problems existing in the prior art. The present invention has simple operation, fast measuring speed and high safety.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] First, some technical terms involved in the embodiments of this application are introduced.

[0045] Concrete is concrete.

[0046] The following combination Figures 1 to 7 , describing embodiments of the present invention.

[0047] The present invention provides a steel casing cast-in-place pile concrete height measuring instrument, comprising: a main pulley 1, an observation rope 6 and a measuring rope 5, the main pulley 1 is used to be arranged on the top of the steel casing 100; one end of the observation rope 6 is connected to a plumb ball 601, and the observation rope 6 is wound around the main pulley 1 along a first circumferential direction with the end connected to the plumb ball 601 as a reference; one end of the measuring rope 5 is connected to a float 7, and the measuring rope 5 is wound around the main pulley 1 along a second circumferential direction with the end connected to the float 7 as a reference; the first circumferential direction and the second circumferential direction are opposite directions, and the float 7 is used to be placed in the steel casing 100; the weight of the plumb ball 601 is less than that of the float 7, and the density of the float 7 is less than that of concrete; in a state of use, the plumb ball 601 is located outside the steel casing 100, and the float 7 floats on the concrete inside the steel casing 100 under the action of buoyancy, and the float 7 can rise as the concrete inside the steel casing 100 increases.

[0048] When the present invention is used, the float 7 is placed inside the steel casing 100 and the plumb ball 601 is placed outside the steel casing 100. Since the observation rope 6 and the measuring rope 5 are wound on the main pulley 1 in opposite directions, when the float 7 changes with the concrete height in the steel casing 100, the main pulley 1 will rotate to cause the plumb ball 601 outside the steel casing 100 to move up and down, so that 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 concrete height measurement speed and high accuracy, 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.

[0049] In some embodiments, the main pulley 1 is a double-groove pulley, and the observation rope 6 and the measuring rope 5 are two separate ropes, respectively. The observation rope 6 and the measuring rope 5 are respectively wound in the two grooves of the main pulley 1 .

[0050] This embodiment sets two ropes as the observation rope 6 and the measuring rope 5, and sets the observation rope 6 and the measuring rope 5 separately, which eliminates the need for the observation rope 6 and the measuring rope 5 to be wound in an orderly manner along a specific direction when they are wound on 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 rope 6 and the measuring rope 5 are formed on one rope. This solution requires that the one rope be wound in the groove in an orderly manner along a certain direction, which requires the use of a wider groove to implement the above solution.

[0051] In some embodiments, the present invention further includes a scale, which is arranged on the outer wall of the steel casing 100 and is arranged vertically.

[0052] The scale in this embodiment serves as a reference standard to enable construction technicians to more accurately know the height of the concrete in the steel casing 100. It can be understood that when setting the position of the scale, it is set as close to the plumb bob 601 as possible, which makes it easier for construction technicians to intuitively check the height of the concrete surface in the steel casing 100.

[0053] In actual application scenarios, when concrete pouring starts in the steel casing 100, the float 7 rises with the concrete surface. Due to gravity balance, the plumb ball 601 at the end of the observation cable 6 drops at the same time. By checking the height mark of the plumb ball 601 on the outside of the steel casing 100, the changes in the buried depth of the steel casing 100 can be checked in real time. After pouring to a certain height, the construction technicians lift the steel casing 100, the height of the inner float 7 remains unchanged, and the plumb ball 601 rises immediately. The buried depth of the steel casing 100 is reflected in real time on the scale line where the counterweight block is located, thereby realizing precise control of the lifting height of the steel casing 100.

[0054] There is no restriction on the material of the scale.

[0055] In some embodiments, the present invention further includes a support frame 2 , which is fixedly disposed on the top edge of the steel casing 100 , and the main pulley 1 is disposed on the support frame 2 .

[0056] This embodiment provides a method for fixing the main pulley 1 .

[0057] Specifically, the support frame 2 may have various structural forms, as long as it can support the main pulley 1 .

[0058] In some examples, the support frame 2 includes two support plates 201. The bottoms of the two support plates 201 are provided with slots for snapping onto the top edge of the steel casing 100. The steel casing 100 is connected to the bottoms of the support plates 201 by bolting, snapping, or welding. The two support plates 201 are arranged parallel to each other and spaced apart. A shaft hole or slot for supporting the pin 3 is provided near the top of the two support plates 201. The two ends of the pin 3 are fixedly inserted into the shaft hole or slot. The main pulley 1 has a center hole in the middle, in which a bearing 105 is provided. The bearing 105 is sleeved on the pin 3. A retaining spring installation slot 301 is provided near each end of the pin 3. The pin 3 passes through the center hole of the main pulley 1. A retaining spring 305 is provided in the retaining spring installation slot 301. The retaining spring 305 is used to limit the position of the bearing 105 and the main pulley 1 on the pin 3.

[0059] The above example is only a specific embodiment. In some examples, the bearing 105 may not be provided, and the pin 3 and the support plate 201 may be made into a rotationally matched structure, and then the main pulley 1 may be fixed or rotationally provided on the pin 3.

[0060] In some embodiments, the embodiments of the present invention also include a cantilever bracket 4 and an auxiliary pulley 401. One end of the cantilever bracket 4 is fixedly connected to the support frame 2, and the other end extends toward 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 frame 2, and the measuring rope 5 is wound around the side of the auxiliary pulley 401 away from the support frame 2.

[0061] 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 cage in the steel casing 100, thereby avoiding interference between the measuring cable 5 and the steel cage.

[0062] The cantilever support 4 can specifically adopt a double steel bar structure, wherein the two steel bars are parallel and spaced apart, one end of the two steel bars is fixedly connected to the support frame 2, and the other end is connected to an auxiliary pulley 401. The steel bars are made of 10 mm thick steel plates.

[0063] In some embodiments, a limit frame 403 is provided at one end of the cantilever bracket 4 where the auxiliary pulley 401 is provided. The limit frame 403 is provided semi-surrounding the auxiliary pulley 401 and together with the auxiliary pulley 401 encloses a measuring rope guide groove. The measuring rope guide groove is used for allowing the measuring rope 5 to pass through. The limit frame 403 is used to limit the position of the measuring rope 5 to prevent the measuring rope 5 from falling out of the guide groove of the auxiliary pulley 401 due to some external factors during use.

[0064] In some embodiments, the float 7 is made of epoxy resin and a counterweight.

[0065] In this embodiment, epoxy resin and counterweight blocks are cast; the density of the float 7 is between cement slurry (1.5g / cm 3 ) and concrete (2.4g / cm 3 ), its density is 1.8g / cm 3 -2.2g / cm 3 , ensuring that it will not float on the cement slurry or sink into the concrete, making the measurement of concrete height more accurate.

[0066] In some embodiments, the float 7 is a conical structure with a bottom diameter of 200 mm, ensuring a sufficiently large contact area between the float and the concrete surface.

[0067] In some embodiments, the measuring cable 5 and the observation cable 6 are steel cables, and the diameter is preferably less than 2 mm.

[0068] In some embodiments, the scale increases from top to bottom, and the height difference between the float 7 and the bottom surface of the steel casing 100 is the size that the plumb bob 601 points to on the scale.

[0069] 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.

[0070] In some embodiments, the pin shaft 3 is 128 mm long and 40 mm in diameter, and a 2 mm wide 2 mm spring plate installation groove 301 is opened 23 mm away from each end of the pin shaft 3, passing through the center hole of the main pulley 1 and connected to the bearing 105 with a spring plate 305. An M6 12 mm deep screw hole 302 is opened in the center of both ends of the pin shaft 3, and is connected to the support plate 201 with a hexagonal head bolt 303 and a pad 304. The hexagonal bolt model is C-grade M6×16, the pad 304 has a diameter of 70 mm, and is made of 5 mm steel plate.

[0071] The main pulley 1 is constructed with a middle partition 103 and two side partitions 104 to form a U-shaped double groove structure. The U-shaped double groove structure includes a measuring cable installation groove 101 and an observation cable installation groove 102.

[0072] The outer diameter of the middle fence 103 is 180 mm, the outer diameter of the fences 104 on both sides is 170 mm, the inner diameter of the center hole of the main pulley 1 is 68 mm, and bearings 105 are installed on both sides of the hole. The model of bearing 105 is 16008-2Z.

[0073] In some embodiments, the plumb ball 601 is a cylindrical structure and is connected to the observation cable 6 by bolts.

[0074] The present invention also provides a steel casing cast-in-place pile concrete construction method, comprising:

[0075] Determine the initial buried depth of the steel casing 100: Calculate the buried depth h1 of the steel casing 100 after the first batch of concrete pouring based on the volume of the first batch of concrete pouring and the pile foundation diameter;

[0076] Install the steel casing bored pile concrete height measuring instrument: Install the steel casing bored pile concrete height measuring instrument and make the height of the plumb bob 601 flush with the h1 scale on the scale;

[0077] Repeat the pouring steps: pour concrete into the steel casing 100 and observe the changes in the buried depth of the steel casing 100. When the set threshold is reached, the steel casing 100 is lifted and buried until the height of the plumb bob 601 is flush with the height of the h1 scale on the scale, and then continue pouring until completion.

[0078] Specifically:

[0079] Step 1: Determine the density of concrete and mud.

[0080] After the pile foundation is bored, the density of the precast concrete (ρ1) and the density of the mud (ρ2) are tested separately in the construction site laboratory.

[0081] Step 2: Make the floating ball 7 and the vertical ball 601.

[0082] Float 7 is manufactured based on the measured test data ρ1 and ρ2. It is made of adjustable-density epoxy resin. Prior to fabrication, the density (ρ3) of float 7 is determined. ρ3 should satisfy the range ρ1 > ρ3 > ρ2 to achieve gravitational balance. The epoxy resin is then mixed in a custom mold. After solidification, the density of float 7 is re-measured to ensure that it meets process requirements. The mass of plumb bob 601 should ideally be 1 / 3 of that of float 7 to maintain the tension of measuring cable 5 and observation cable 6.

[0083] The weight requirement of the plumb bob 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).

[0084] Step 3: Bury the steel casing 100 and post the scale

[0085] 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 continued to be posted to meet observation requirements.

[0086] Step 4: Make the support frame 2, the main pulley 1 and the auxiliary pulley 401, etc.

[0087] The measuring cable 5 and observation cable 6 are 2mm diameter steel cables, with lengths tailored to the length of the pile foundation. The measuring cable 5 is installed in the measuring cable mounting slot 101, passed through the auxiliary pulley 401, and positioned inside the steel casing 100. A float 7 is attached to the end. The observation cable 6 is installed in the observation cable mounting slot 102, inside the steel casing 100, and attached to the end with a plumb bob 601. The two cables are installed in opposite directions.

[0088] 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.

[0089] Carry out the first batch of concrete pouring, and calculate the buried depth h1 of the steel casing 100 after the first batch of concrete pouring based on the volume of the first batch of concrete pouring and the pile foundation diameter.

[0090] The measuring instrument is mounted on the top surface of the steel casing 100 via the support frame 2, with the measuring cable 5 and observation cable 6 placed on the inside and outside of the steel casing 100, respectively. A height scale is set on the steel casing 100. The measuring cable 5 is connected to a floating ball 7 and placed on the inside of the steel casing 100 and lowered to the concrete surface. The observation cable 6 is connected to a plumb bob 601 and placed on the outside of the steel casing 100. The plumb bob 601 is positioned at the h1 scale mark on the scale.

[0091] Step 6: Continue pouring pile foundation concrete

[0092] 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.

[0093] Step 7: Pull up the steel casing 100

[0094] The casing depth is monitored in real time using the corresponding scales on the plumb bob 601 and the observation cable 6. When the casing depth exceeds 4 meters, the steel casing 100 is lifted. When the casing is lifted to a depth of 2 meters, concrete pouring continues. The process of observing the scale, lifting the steel casing 100, and pouring concrete is repeated until the pile foundation is completed and the steel casing 100 is fully removed.

[0095] The present invention has the following characteristics:

[0096] (1) The steel casing cast-in-place pile concrete height measuring instrument provided by the present invention is easy to manufacture, simple to install and operate, and has the characteristics of fast measuring speed and high precision in controlling the lifting height of the steel casing 100 during the pouring of cast-in-place pile concrete, and can effectively ensure the quality of pile foundation construction.

[0097] (2) The conventional method of measuring concrete height with a measuring rope has a great risk of falling. However, the use of the steel casing 100 cast-in-place pile concrete height automatic measuring instrument can measure the concrete height outside the casing, which can effectively avoid the safety risks of the conventional method.

[0098] Principle: The steel casing cast-in-place pile concrete height measuring instrument is fixed to the upper edge of the pile foundation steel casing 100 via a support frame 2. In practice, the main pulley 1 rotates in real time, influenced by the real-time changes in the float 7, plumb ball 601, and the concrete surface inside the steel casing 100. This causes the height of the plumb ball 601 to change. This allows the concrete surface height change to be accurately measured using a scale on the outside of the steel casing 100, providing guidance on how high the steel casing 100 should be raised.

[0099] The benefit analysis of the present invention is:

[0100] The steel casing cast-in-place pile concrete height measuring instrument provided by the present invention has the advantages of being easy to manufacture, install, and operate. Compared to conventional rope-based concrete elevation measurement methods, it offers higher measurement accuracy and lower safety risks. It effectively avoids pile foundation quality defects caused by prematurely removing the steel casing 100 during concrete pouring. This method is safe, environmentally friendly, and has significant social benefits and practical value.

[0101] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A steel casing cast-in-place pile concrete height measuring instrument, characterized by: include: A main pulley is used to be arranged on the top of the steel casing; an observation rope, one end of which is connected to a plumb bob, and the observation rope is wound around the main pulley along a first circumferential direction with the end connected to the plumb bob as a reference; a measuring rope, one end of which is connected to a float; the measuring rope is wound around the main pulley along a second circumferential direction, with the end connected to the float as a reference; the first circumferential direction and the second circumferential direction are opposite directions; the float is used to be placed in the steel casing; the weight of the plumb ball is less than that of the float, and the density of the float is less than that of concrete; When in use, the plumb ball is located outside the steel casing, and the float floats on the concrete inside the steel casing under the action of buoyancy; the main pulley is a double-groove pulley, and the observation rope and the measuring rope are two separate ropes, and the observation rope and the measuring rope are respectively wound in the two grooves of the main pulley; it also includes a scale, and the scale is used to be set on the outer wall of the steel casing, and the scale is set vertically; it also includes a support frame, and the support frame is fixedly set on the top edge of the steel casing, and the main pulley is set on the support frame; the main pulley and the support frame are both set above the steel casing.

2. The steel casing cast-in-place pile concrete height measuring instrument according to claim 1, characterized in that: It also includes a cantilever bracket and an auxiliary pulley, one end of the cantilever bracket is fixedly connected to the support frame, and the other end extends toward the center of the cylindrical space where the steel casing is located. The auxiliary pulley is provided at the end of the cantilever bracket away from the support frame, and the measuring rope is wound around the side of the auxiliary pulley away from the support frame.

3. The steel casing cast-in-place pile concrete height measuring instrument according to claim 1, characterized in that: The float is made of epoxy resin and a counterweight.

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

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

6. The steel casing cast-in-place pile concrete height measuring instrument according to claim 1, characterized in that: The measuring rope and the observation rope are steel ropes.

7. A method for the construction of steel casing cast-in-place pile concrete, characterized by: include: Determine the initial buried depth of the steel casing: Calculate the buried depth h1 of the steel casing after the first batch of concrete pouring based on the volume of the first batch of concrete pouring and the pile foundation diameter; Install the steel casing bored pile concrete height measuring instrument: Install the steel casing bored pile concrete height measuring instrument and make sure the height of the plumb ball is flush with the h1 scale on the scale; Repeat the pouring steps: pour concrete into the steel casing and observe the changes in the buried depth of the steel casing. When the set threshold is reached, lift the steel casing and bury it until the height of the plumb bob is flush with the h1 scale on the scale, and then continue pouring until completion; Among them, the steel casing cast-in-place pile concrete height measuring instrument is the steel casing cast-in-place pile concrete height measuring instrument according to any one of claims 1 to 6.

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