Construction method for controlling burying depth of guide pipe in pouring process of cast-in-place pile

Abstract

The invention relates to the technical field of cast-in-place pile construction, in particular to a construction method for controlling the buried depth of a guide pipe in the cast-in-place pile pouring process. The length of the guide pipe is calculated by monitoring the height of the hook head of the crane and the height of the concrete pouring surface, so that the bottom of the guide pipe is controlled to be buried 2-6 m below the concrete pouring surface. Wherein the crane hook head height monitoring needs to install a distance sensor on a winch, the concrete pouring surface height is digitally monitored in real time by adopting a guide pipe burial depth control device and a concrete pouring surface monitoring system in the cast-in-place pile pouring process, and the guide pipe length is calculated according to the mark number of each section of guide pipe. The pipe embedding depth in the pouring process of the cast-in-place pile can be effectively controlled, and quality accidents caused by the fact that the pipe is pulled out of a concrete pouring face due to manual operation errors or calculation errors are avoided, and the cast-in-place pile is broken. Therefore, the embedding depth of the guide pipe is accurately monitored in real time, the construction quality in the pouring process of the cast-in-place pile is improved, and the overall construction quality of the cast-in-place pile is controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of cast-in-place pile construction, and particularly relates to a construction method for controlling the buried depth of a conduit during the pouring process of a cast-in-place pile. Background Art

[0002] Cast-in-place piles are a commonly used type of pile foundation in engineering construction. Due to their high bearing capacity and the ability to adapt to any geology, they are widely used in projects. However, since the construction process of cast-in-place piles has many procedures, each procedure needs to meet quality requirements to ensure the overall construction quality of the cast-in-place piles. Among these numerous procedures, concrete pouring often becomes the key point of quality control. For example, if the volume of the first batch of poured concrete does not meet the specification requirements, the distance between the conduit and the bottom of the hole is too large or too small, the pouring is interrupted due to other reasons during the pouring process, the buried depth of the conduit does not meet the requirements or the conduit is pulled out of the concrete pouring surface, etc., all of which will affect the quality of the cast-in-place pile. In particular, this control index of the buried depth of the conduit runs through the entire process of cast-in-place pile pouring, and once the conduit is pulled out of the concrete pouring surface, there will be a risk of pile breakage, which cannot be remedied. Therefore, this procedure is the most critical link in the quality control of cast-in-place pile construction.

[0003] In existing construction, the method for controlling the buried depth of the conduit is to measure the distance from the concrete surface to the ground by connecting a certain weight of iron piece with a sounding rope, and then record the change in the length of the conduit during the construction process, and determine the buried depth of the conduit through the calculation of the two data. The problems existing in this method are that the measurement of the concrete surface position by connecting a certain weight of iron piece with a sounding rope is inaccurate. Since the concrete at the top of the pile is often mixed with mud, the weight and shape of the iron piece will both affect the measurement data. At the same time, since the buried depth of the conduit is obtained by calculating the change value of the conduit length and the position of the concrete surface for the second time, each section of the conduit in construction is only 3m, and generally there are many sections of the pile foundation conduit. During the construction process, as the concrete top surface rises, the length of the conduit changes accordingly. It is very easy to make mistakes in recording the number of conduits during the construction, resulting in the buried depth of the conduit not meeting the design requirements and quality problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a construction method for controlling the buried depth of a conduit during the pouring process of a cast-in-place pile in view of the above-mentioned existing technical problems.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: a construction method for controlling the buried depth of a conduit during the pouring process of a cast-in-place pile, which is characterized by including the following steps: The first step: Select construction equipment according to geological characteristics and carry out hole-forming construction Select appropriate cast-in-place pile mechanical equipment according to different geological characteristics, including special equipment such as impact drilling rigs, positive and reverse circulation drilling rigs, rotary drilling rigs, and grab drilling rigs. After the construction equipment is completed, start the hole-forming construction of the cast-in-place pile.

[0006] Step 2: Lower the steel cage of the cast-in-place pile according to the construction process After the construction of the cast-in-place pile hole is completed, the first hole cleaning is carried out. The sediment thickness of the end-bearing cast-in-place pile is not more than 5 cm, and the sediment thickness of the friction pile is not more than 10 cm. The next steel cage construction process can only be carried out after passing the acceptance. According to the length of the cast-in-place pile, the steel cage is fabricated and installed in each section, and mechanical connection is used for the connection between sections. Attention should be paid to the quality, installation quantity and position requirements of the cushion blocks. At the same time, the installation and connection construction of the acoustic logging tubes should be done well to avoid damage during the construction process, which may affect the pile foundation detection. After the steel cage is lowered, the second hole cleaning is carried out according to the sediment situation at the bottom of the hole. The next process construction can be carried out after meeting the requirements of the design specifications.

[0007] Step 3: Make good the trial assembly and pressure test of the conduit and do the numbering Before pouring the concrete of the cast-in-place pile, it is necessary to determine the number of pipe sections and the length of each section according to the length of the cast-in-place pile. Marks should be made on each pipe section from top to bottom, including the length of a single pipe section, the pipe section serial number and the total length of the pipe section. Then the conduit is subjected to trial assembly and pressure test, and the test pressure is not less than 1.3 times the water depth pressure in the hole.

[0008] Step 4: Install a distance sensor on the winch of the hoisting equipment After the conduit is marked and tested, a distance sensor is installed on the winch of the hoisting equipment, and a Beidou satellite positioning system is installed at the top of the hoisting equipment's boom. Since the hoisting operation of the conduit needs to be carried out by the hoisting equipment during the concrete pouring process of the cast-in-place pile to complete the concrete pouring. Therefore, the height H1 of the hook can be effectively measured by the distance sensor on the winch, and the Beidou satellite positioning system can display the distance H2 from the top of the boom to the ground.

[0009] Step 5: Prepare the monitoring equipment for the concrete pouring surface The monitoring equipment for the concrete pouring surface consists of three parts: height sensors with a certain density, transmission lines, and a digital platform. The height sensors are spherical structures, and the working principle is that the relative density of the sensors themselves is controlled to be 2.25. During the concrete pouring process, they are placed in the cast-in-place pile. Since the relative density of the concrete is between 2.35 and 2.4, the relative density of the mixed layer at the interface between the concrete and the mud varies greatly according to the soil quality, about between 1.6 and 2.1, and the maximum relative density of the mud does not exceed 1.45. In this way, it can be ensured that the height sensors always stay at the top of the concrete during the concrete pouring process, accurately monitor the elevation of the concrete surface, and at the same time upload it to the digital platform through the transmission lines.

[0010] Step 6: Pour the concrete and control the buried depth of the conduit After the height sensor is installed, concrete pouring is carried out. The concrete is transported to the site by a mixer truck and poured into the conduit in a self-unloading manner. The crane raises the conduit according to the situation of concrete pouring. According to the distance H3 between the monitored concrete pouring surface and the ground, the height H1 of the hoist hook of the lifting facility, the distance H2 from the highest point of the lifting equipment to the ground, and the conduit length H4, the buried depth H of the conduit can be calculated. Among the above data, H1 and H2 transmit data to the digital platform through wireless signals, while H3 is connected to the digital platform through the transmission line of the sensor. By manually inputting the conduit length, the value of the buried depth H of the conduit can be automatically calculated. Where H = H1 + H4 - (H2 + H3). According to the requirements of the design specification, ensure that H is controlled within 2 - 6m, and the conduit segments are disassembled in a timely manner until the casting of the cast-in-place pile concrete is completed.

[0011] Step 7: After the casting of the cast-in-place pile is completed, perform ultrasonic testing on the pile foundation After the casting of the cast-in-place pile is completed and reaches the age, ultrasonic testing is carried out to verify whether the integrity of the pile foundation meets the requirements of the design specification.

[0012] A device for controlling the buried depth of a conduit during the casting of a cast-in-place pile, characterized in that it includes a distance sensor, a Beidou satellite positioning system, and a concrete pouring surface monitoring device; the distance sensor is connected to the hoist of the lifting equipment; the Beidou satellite positioning system is connected to the top of the boom of the lifting equipment; the concrete pouring surface monitoring device includes height sensors with a certain density, transmission lines, and a digital platform. The height sensors are placed in the cast-in-place pile together with the conduit during concrete pouring; the Beidou satellite positioning system and the distance sensor are connected to the digital platform through wireless signals, and the height sensors are connected to the digital platform through transmission lines.

[0013] Before the concrete of the cast-in-place pile is poured, determine the number of pipe sections and the length of each section according to the length of the cast-in-place pile. Make marks on every few pipe sections from top to bottom. The marks include the length of a single pipe section, the pipe section serial number, and the total length of the pipe section.

[0014] After the conduit is trial-assembled, a pressure test is carried out on the conduit, and the test pressure is not less than 1.3 times the water depth pressure in the hole.

[0015] The height sensor is in a spherical structure with a relative density of 2.25.

[0016] The present invention controls the bottom burial of the conduit 2 - 6m below the concrete pouring surface by monitoring the height of the crane hook head and the height of the concrete pouring surface and calculating the conduit length. Among them, the monitoring of the crane hook head height requires the installation of a distance sensor on the hoist, and the height of the concrete pouring surface is digitally monitored in real time by the concrete pouring surface monitoring system invented in this device and construction plan. The conduit length is calculated based on the label of each conduit section.

[0017] The present invention can effectively control the buried depth of the conduit during the casting of cast-in-place piles, avoid the conduit being pulled out of the concrete casting surface due to human operation errors or calculation mistakes, form a broken pile in the cast-in-place pile, and cause quality accidents. Thus, it can monitor the buried depth of the conduit in real time and accurately, improve the construction quality during the casting of cast-in-place piles, and ensure the overall construction quality of cast-in-place piles is under control. Brief Description of the Drawings

[0018] Figure 1 It is a construction schematic diagram of the present invention; In the figure: 1. Beidou satellite positioning system; 2. Distance sensor; 3. Lifting equipment; 4. Hook; 5. Transmission line; 6. Digital platform; 7. Height sensor; 8. Conduit; 9. Cast-in-place pile. Detailed Embodiments

[0019] The present invention will be further described below in conjunction with the drawings, but the present invention is not limited to specific embodiments.

[0020] Embodiment 1

[0021] A device for controlling the buried depth of the conduit during the casting of cast-in-place piles includes a distance sensor 2, a Beidou satellite positioning system 1, and a concrete casting surface monitoring device; the distance sensor 2 is connected to the winch of the lifting equipment 3; the Beidou satellite positioning system 1 is connected to the top end of the boom of the lifting equipment 3; the concrete casting surface monitoring device includes height sensors 7 with a certain density, a transmission line 5, and a digital platform 6. The height sensors 7 are placed in the cast-in-place pile 9 together with the conduit 8 during the concrete casting process; the Beidou satellite positioning system 1 and the distance sensor 2 are connected to the digital platform 6 through wireless signals, and the height sensors 7 are connected to the digital platform 6 through the transmission line 5.

[0022] Before the cast-in-place pile 9 is filled with concrete, the number of pipe sections and the length of each section are determined according to the length of the cast-in-place pile 9, and marks are made on every few pipe sections from top to bottom. The marks include the length of a single pipe section, the pipe section serial number, and the total length of the pipe section.

[0023] After the conduit 8 is assembled and tested, a pressure test is carried out on the conduit 8, and the test pressure is not less than 1.3 times the water depth pressure in the hole.

[0024] The height sensor 7 is of a spherical structure and its relative density is 2.25.

[0025] Embodiment 2

[0026] A construction method for controlling the buried depth of the conduit during the casting of cast-in-place piles by using the device described in Embodiment 1 includes the following steps: The first step: Select construction equipment according to geological characteristics and carry out hole-forming construction Select appropriate cast-in-place pile machinery and equipment according to different geological characteristics, including impact drills, positive and reverse circulation drills, rotary drilling rigs, and special equipment for grab bucket drills. After the construction equipment is completed, the construction of the cast-in-place pile hole begins.

[0027] Step 2: Lower the steel cage of the cast-in-place pile according to the process After the construction of the cast-in-place pile hole, the first hole cleaning is carried out. The sediment thickness of end-bearing cast-in-place piles shall not be greater than 5 cm, and the sediment thickness of friction piles shall not be greater than 10 cm. The next steel cage construction process can only be carried out after passing the acceptance. According to the length of the cast-in-place pile, the steel cage is fabricated and installed in each section, and mechanical connection is used for connection between sections. Attention shall be paid to the quality, installation quantity and position requirements of the cushion blocks. At the same time, the installation and connection construction of the acoustic logging tubes shall be done well to avoid damage during the construction process, which will affect the pile foundation detection. After the steel cage is lowered, the second hole cleaning is carried out according to the sediment situation at the bottom of the hole. The next process can be carried out after meeting the requirements of the design specifications.

[0028] Step 3: Do a good job in the trial assembly and pressure test of the conduit and number it Before pouring concrete for the cast-in-place pile, it is necessary to determine the number of pipe sections and the length of each section according to the length of the cast-in-place pile. Markings shall be made on each pipe section from top to bottom, including the length of a single pipe section, the pipe section serial number, and the total length of the pipe section. Then, conduct a trial assembly and pressure test on the conduit. The test pressure shall not be less than 1.3 times the water depth pressure in the hole.

[0029] Step 4: Install a distance sensor on the winch of the hoisting equipment After the conduit is marked and tested, install a distance sensor on the winch of the hoisting equipment, and install a Beidou satellite positioning system at the top of the boom of the hoisting equipment. Since the hoisting operation of the conduit needs to be carried out by the hoisting equipment during the concrete pouring process of the cast-in-place pile to complete the concrete pouring. Therefore, the height H1 of the hook can be effectively measured by the distance sensor on the winch, and the Beidou satellite positioning system can display the distance H2 from the top of the boom to the ground.

[0030] Step 5: Prepare the monitoring equipment for the concrete pouring surface The monitoring device for the concrete pouring surface consists of three parts: height sensors 7 with a certain density, transmission lines 5, and a digital platform 6. Among them, the height sensor 7 has a spherical structure. The working principle is that the relative density of the sensor itself is controlled at 2.25. During the concrete pouring process, it is placed in the cast-in-place pile 9. Since the relative density of the concrete is between 2.35 and 2.4, and the relative density of the mixed layer at the interface between the concrete and the mud varies greatly depending on the soil quality, between 1.6 and 2.1, and the maximum relative density of the mud does not exceed 1.45. This can ensure that the height sensor 7 always stays at the top of the concrete during the concrete pouring process, accurately monitors the elevation of the concrete surface, and at the same time uploads it to the digital platform 6 through the transmission line 5.

[0031] Step 6: Pour the concrete and control the buried depth of the conduit After the height sensor 7 is installed, the concrete is poured. The concrete is transported to the site by a tank truck and poured into the conduit 8 in a self-unloading manner. The crane raises the conduit 8 according to the situation of the poured concrete. Based on the distance H3 between the monitored concrete pouring surface and the ground, the height H1 of the lifting hook 4 of the hoisting facility, the distance H2 from the highest point of the hoisting equipment 3 to the ground, and the length H4 of the conduit 8, the buried depth H of the conduit 8 can be calculated. Among the above data, H1 and H2 transmit data to the digital platform through wireless signals, and H3 is connected to the digital platform through the transmission line of the sensor. By manually inputting the length of the conduit 8, the value of the buried depth H of the conduit can be automatically calculated. Among them, H = H1 + H4 - (H2 + H3). According to the requirements of the design specifications, ensure that H is controlled within 2 - 6m, and promptly disassemble the conduit segments until the concrete pouring of the cast-in-place pile is completed.

[0032] Step 7: Conduct ultrasonic testing on the pile foundation after the cast-in-place pile is poured After the cast-in-place pile 9 is poured and reaches the age, ultrasonic testing is carried out to verify whether the integrity of the pile foundation meets the requirements of the design specifications.

Claims

1. A construction method for controlling the buried depth of a guide tube during the pouring of a bored pile, characterized in that: The following steps are involved: Step 1: Select construction equipment according to geological characteristics and carry out hole-forming construction; Step 2: Lower the cast-in-place pile reinforcement cage according to the procedure; Step 3: Carry out the catheter trial assembly and pressure test, and make the numbering; Step 4: Install the distance sensor to measure the height H1 of the hook, and install the Beidou satellite positioning system to display the distance H2 from the top of the boom to the ground; Step 5: Prepare the concrete pouring surface monitoring equipment; Step 6: Concrete pouring, the crane lifts the conduit according to the concrete pouring situation, and the buried depth of the conduit H=H1+H4-(H2+H3) is calculated based on the monitored concrete pouring surface height H3, the hoisting hook height H1 of the lifting equipment, the distance H2 from the highest point of the lifting equipment to the ground, and the conduit length H4; Step 7: After the bored piles are cast and reach the age, ultrasonic testing of the pile foundation is carried out to verify whether the integrity of the pile foundation meets the design specification requirements.

2. A construction method for controlling the buried depth of a guide tube during the pouring of a bored pile according to claim 1, characterized in that: In the first step, bored pile machinery and equipment are selected according to different geological characteristics, and bored pile hole construction is started after the construction equipment is selected; bored pile machinery and equipment include impact drills, forward and reverse circulation drills, rotary drilling rigs, and impact grab drills.

3. The construction method for controlling the buried depth of the guide tube during the pouring process of the bored pile according to claim 1, characterized in that: In the second step, the first hole cleaning is carried out after the bored pile construction, wherein the sediment thickness of the end-bearing bored pile is not more than 5 cm, and the sediment thickness of the friction pile is not more than 10 cm; after qualified acceptance, the next steel cage construction process is carried out; according to the length of the bored pile, the steel cage is manufactured and installed section by section, and the mechanical connection method is used for the connection between the sections, and attention is paid to the quality of the pads, the number of installations and the position requirements, and the installation and connection construction of the acoustic detection pipe are carried out at the same time; after the steel cage is lowered, the hole is cleaned for the second time according to the sediment situation at the bottom of the hole, and the next construction process is carried out after meeting the design specifications.

4. The construction method for controlling the buried depth of the guide tube during the pouring process of the bored pile according to claim 1, characterized in that: In the third step, before pouring concrete for the bored pile, the number of pipe segments and the length of each segment are determined according to the length of the bored pile, and markings are made on every few pipe segments from top to bottom, including the length of a single pipe segment, the serial number of the pipe segment and the total length of the pipe segment; then the conduit is subjected to trial assembly and pressure testing, wherein the test pressure is not less than 1.3 times the water depth pressure in the hole.

5. The construction method for controlling the buried depth of the guide tube during the pouring process of the bored pile according to claim 1, characterized in that: In the fourth step, a distance sensor is installed on the hoist of the lifting equipment, and a Beidou satellite positioning system is installed on the top of the lifting arm of the lifting equipment.

6. The construction method for controlling the buried depth of the guide tube during the pouring process of the bored pile according to claim 1, characterized in that: In the fifth step, the concrete pouring surface monitoring equipment includes three parts: a height sensor, a transmission line, and a digital platform; during the concrete pouring process, the height sensor always stays on the top of the concrete to accurately monitor the elevation of the top surface of the concrete, and is uploaded to the digital platform through the transmission line; the height sensor is a spherical structure, and the relative density of the sensor itself is controlled to be 2.

25. During the concrete pouring process, it is placed in the bored pile. Since the relative density of concrete is between 2.35-2.4, the relative density of the mixed layer at the interface between concrete and mud is between 1.6-2.1, and the relative density of the mud does not exceed 1.

45.

7. The construction method for controlling the buried depth of the guide tube during the pouring of the bored pile according to claim 1, characterized in that: In the sixth step, H1 and H2 transmit data to the digital platform through wireless signals, H3 is connected to the digital platform through the transmission line of the sensor, and the catheter length is manually input to automatically calculate the catheter burial depth H value. According to the design specification requirements, H is controlled at 2-6m, and the catheter segments are disassembled in time until the pouring of the bored pile concrete is completed; the concrete is transported to the site by a tank truck and poured into the catheter by self-unloading.

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