A construction method for controlling the buried depth of the conduit during the casting of cast-in-place piles

Abstract

The present invention relates to the technical field of cast-in-place pile construction, and particularly to a construction method for controlling the buried depth of a conduit during the casting of a cast-in-place pile. The present invention calculates the length of the conduit by monitoring the height of the crane hook head and the height of the concrete casting surface, so as to control the bottom of the conduit to be buried 2 - 6 m below the concrete casting surface. Among them, a distance sensor needs to be installed on the winch for monitoring the height of the crane hook head, and the height of the concrete casting surface is digitally monitored in real time by using a device for controlling the buried depth of the conduit during the casting of the cast-in-place pile and a monitoring system for the concrete casting surface. The length of the conduit is calculated according to the label of each section of the conduit. The present invention can effectively control the buried depth of the conduit during the casting of the cast-in-place pile, avoid the conduit being pulled out of the concrete casting surface due to human operation errors or calculation errors, form a broken pile in the cast-in-place pile, and cause quality accidents. Thus, the buried depth of the conduit can be monitored in real time and accurately, the construction quality during the casting of the cast-in-place pile can be improved, and the overall construction quality of the cast-in-place pile can be ensured to be under control.

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 casting 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 geological conditions, they are widely used in projects. However, since the construction process of cast-in-place piles has many procedures, each procedure must meet the 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 piles. In particular, the 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, it will cause the 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 calculate and determine the buried depth of the conduit through the two data. The problems with 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 affect the measurement data. At the same time, since the buried depth of the conduit is obtained by secondary calculation of recording the change value of the conduit length and the position of the concrete surface, 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 construction, resulting in the buried depth of the conduit not meeting the design requirements and quality problems occurring. 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 casting process of a cast-in-place pile in view of the above-mentioned problems of the prior art.

[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 casting process of a cast-in-place pile, characterized by including the following steps:

[0006] The first step: Select construction equipment according to geological characteristics and carry out hole-forming construction

[0007] Select appropriate cast-in-place pile construction machinery and 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.

[0008] Step 2: Lower the bored pile reinforcement cage according to the construction process

[0009] After the bored pile hole forming construction, the first hole cleaning is carried out. Among them, the sediment thickness of end-bearing bored piles shall not be greater than 5 cm, and the sediment thickness of friction piles shall not be greater than 10 cm. The next reinforcement cage construction process can be carried out only after passing the acceptance. According to the length of the bored pile, the reinforcement 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 may affect the pile foundation detection. After the reinforcement cage is lowered, the secondary 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.

[0010] Step 3: Do a good job in the trial assembly and pressure test of the conduit and number it

[0011] Before pouring the concrete for the bored pile, it is necessary to determine the number of pipe sections and the length of each section according to the length of the bored pile, and make marks 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 assembled and tested, and the test pressure shall not be less than 1.3 times the water depth pressure in the hole.

[0012] Step 4: Install a distance sensor on the winch of the hoisting equipment

[0013] 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 bored 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 distance H2 from the top of the boom to the ground can be displayed by the Beidou satellite positioning system.

[0014] Step 5: Prepare the monitoring equipment for the concrete pouring surface

[0015] The monitoring equipment for the concrete pouring surface consists of three parts: height sensors with a certain density, transmission lines, and a digital platform. Among them, the height sensor is spherical in structure, and its 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 bored 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. This can ensure that the height sensor always stays at the top of the concrete during the concrete pouring process, accurately monitoring the elevation of the concrete top surface, and at the same time uploading it to the digital platform through the transmission line.

[0016] Step 6: Pour the concrete and control the buried depth of the conduit

[0017] After the height sensor is installed, concrete pouring is carried out. The concrete is transported to the site by a tank truck and poured into the conduit in a self-dumping manner. The crane raises the conduit according to the situation of the concrete pouring. Based on the distance H3 between the monitored concrete pouring surface and the ground, the height H1 of the lifting hook of the hoist of the lifting equipment, the distance H2 from the highest point of the lifting equipment to the ground, and the length H4 of the conduit, 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, H3 is connected to the digital platform through the transmission line of the sensor, and the conduit length is manually input, and then 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 time until the concrete pouring of the cast-in-place pile is completed.

[0018] Step 7: After the cast-in-place pile is poured, perform ultrasonic testing on the pile foundation

[0019] After the cast-in-place pile 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 specification.

[0020] A device for controlling the buried depth of the conduit during the pouring of a cast-in-place pile, characterized by including 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, and the height sensors are placed in the cast-in-place pile together with the conduit during the concrete pouring process; 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.

[0021] 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, and 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.

[0022] After the conduit is pre-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.

[0023] The height sensor is of a spherical structure and its relative density is 2.25.

[0024] The present invention monitors the height of the crane hook and the height of the concrete pouring surface, calculates the length of the conduit, and thus controls the burial of the bottom of the conduit 2 - 6 m below the concrete pouring surface. Among them, a distance sensor needs to be installed on the winch for monitoring the height of the crane hook, and the height of the concrete pouring surface is digitally monitored in real time by using the concrete pouring surface monitoring system invented in this device and construction plan. The length of the conduit is calculated according to the label of each section of the conduit.

[0025] The present invention can effectively control the burial depth of the conduit during the pouring of the cast-in-place pile, avoid the conduit being pulled out of the concrete pouring surface due to human operation errors or calculation errors, form a broken pile in the cast-in-place pile, and cause quality accidents. Thus, it can monitor the burial depth of the conduit in real time and accurately, improve the construction quality during the pouring of the cast-in-place pile, and ensure the overall construction quality of the cast-in-place pile is under control. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic construction diagram of the present invention;

[0027] 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 DESCRIPTION OF THE EMBODIMENTS

[0028] The present invention will be further described below in conjunction with the drawings, but the present invention is not limited to specific embodiments.

[0029] Embodiment 1

[0030] A device for controlling the burial depth of the conduit during the pouring of a cast-in-place pile includes a distance sensor 2, a Beidou satellite positioning system 1, and a concrete pouring 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 pouring 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 pouring 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.

[0031] Before pouring concrete into the cast-in-place pile 9, 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.

[0032] 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.

[0033] The height sensor 7 is spherical in structure and has a relative density of 2.25 by itself.

[0034] Embodiment 2

[0035] A construction method for controlling the buried depth of the conduit during the casting of cast-in-place piles is implemented using the device described in Embodiment 1, including the following steps:

[0036] The first step: Select construction equipment according to geological characteristics and carry out hole-forming construction

[0037] Select appropriate cast-in-place pile mechanical equipment according to different geological characteristics, including impact drilling rigs, positive and reverse circulation drilling rigs, rotary drilling rigs, and special equipment for grab drilling rigs. After the construction equipment is completed, start the hole-forming construction of the cast-in-place pile.

[0038] The second step: Carry out the construction of lowering the steel cage of the cast-in-place pile according to the process

[0039] After the hole-forming construction of the cast-in-place pile, the first hole cleaning is carried out. Among them, 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 construction process of the steel cage can be carried out only after passing the acceptance. According to the length of the cast-in-place pile 9, the steel cage is fabricated and installed in each section, and mechanical connection is used for connection between sections. At the same time, pay attention to the quality, installation quantity and position requirements of the cushion blocks, and do a good job in the installation and connection construction of the acoustic logging tubes to avoid damage during the construction process and 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. After meeting the requirements of the design specifications, the next process construction can be carried out.

[0040] The third step: Do a good job in the trial assembly and pressure test of the conduit and number it

[0041] Before pouring concrete for the cast-in-place pile 9, 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 9, and make marks 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, carry out the trial assembly and pressure test on the conduit 8, and the test pressure shall not be less than 1.3 times the water depth pressure in the hole.

[0042] The fourth step: Install the distance sensor 2 on the winch of the hoisting equipment 3

[0043] After the conduit 8 is marked and tested, install the distance sensor 2 on the winch of the hoisting equipment 3, and install the Beidou satellite positioning system 1 at the top of the boom of the hoisting equipment 3. Since the hoisting operation of the conduit 8 needs to be carried out by the hoisting equipment during the concrete pouring process of the cast-in-place pile 9 to complete the concrete pouring. Therefore, the height H1 of the hook 4 can be effectively measured by the distance sensor 2 of the winch, and the Beidou satellite positioning system 1 can display the distance H2 from the top of the boom to the ground.

[0044] The fifth step: Prepare the concrete pouring surface monitoring equipment

[0045] The monitoring equipment 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, 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 top surface, and at the same time uploads it to the digital platform 6 through the transmission line 5.

[0046] Step 6: Pour the concrete and control the buried depth of the conduit

[0047] 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 lifts 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 hoist hook 4 of the lifting equipment, the distance H2 from the highest point of the lifting 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.

[0048] Step 7: Conduct ultrasonic testing on the pile foundation after the cast-in-place pile is poured

[0049] 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 conduit during the casting of a cast-in-place pile, characterized in that It includes the following steps: The first step: Select construction equipment according to geological characteristics and carry out hole-forming construction; The second step: Carry out the construction of placing the reinforcement cage of the cast-in-place pile according to the working procedures; The third step: Do a good job in the trial assembly and pressure test of the conduit and number it; The fourth step: Install a distance sensor on the winch of the hoisting equipment to measure the height H1 of the hook, and install a Beidou satellite positioning system at the top of the boom of the hoisting equipment to display the distance H2 from the top of the boom to the ground; The fifth step: Prepare the monitoring equipment for the concrete pouring surface; The monitoring equipment for the concrete pouring surface 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 concrete top surface, and at the same time uploads it 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 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 is between 1.6 and 2.1, and the relative density of the mud does not exceed 1.45; The sixth step: Carry out concrete pouring. The crane raises the conduit according to the situation of the poured concrete. According to the monitored height H3 of the concrete pouring surface, the height H1 of the hook of the winch of the hoisting facility, the distance H2 from the highest point of the hoisting equipment to the ground, and the length H4 of the conduit, calculate the buried depth H of the conduit = H1 + H4 - (H2 + H3); 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 length of the conduit is manually input to automatically calculate the value of the buried depth H of the conduit. According to the requirements of the design specifications, ensure that H is controlled within 2 - 6m, and remove the conduit segments in time until the concrete pouring of the cast-in-place pile is completed; The concrete is transported to the site by a tank truck and poured into the conduit by self-unloading; The seventh step: Carry out ultrasonic testing of the pile foundation after the cast-in-place pile is poured and reaches the age; To verify whether the integrity of the pile foundation meets the requirements of the design specifications.

2. The construction method for controlling the buried depth of the conduit during the casting of cast-in-place piles according to claim 1, characterized in that, In the first step, select cast-in-place pile machinery and equipment according to different geological characteristics. After the construction equipment is selected, start the hole-forming construction of the cast-in-place pile; The cast-in-place pile machinery and equipment include impact drills, positive and reverse circulation drills, rotary drilling rigs, and grab drills.

3. The construction method for controlling the buried depth of the conduit during the casting of cast-in-place piles according to claim 1, characterized in that, In the second step, after the hole-forming construction of the cast-in-place pile, carry out the first hole cleaning. Among them, the sediment thickness of the end-bearing cast-in-place pile is not more than 5cm, and the sediment thickness of the friction pile is not more than 10cm; After passing the acceptance, carry out the next reinforcement cage construction procedure; According to the length of the cast-in-place pile, the reinforcement cage is fabricated and installed in each section, and mechanical connection is used for connection between sections. Pay attention to the quality, installation quantity and position requirements of the cushion blocks, and at the same time do a good job in the installation and connection construction of the acoustic logging tubes; After the reinforcement cage is lowered, carry out the secondary hole cleaning according to the sediment situation at the bottom of the hole, and carry out the next procedure construction after meeting the requirements of the design specifications.

4. A construction method for controlling the buried depth of a conduit during the casting of a cast-in-place pile according to claim 1, characterized in that, In the third step, before pouring concrete for the cast-in-place pile, determine the number of pipe sections and the length of each section according to the length of the cast-in-place pile, and make marks on every few pipe sections from top to bottom, including the length of a single pipe section, the pipe section serial number, and the total length of the pipe sections; then conduct trial assembly and pressure test on the conduit, and the test pressure shall not be less than 1.3 times the water depth pressure in the hole.

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