Pre-set fracture-type driven steel pipe pile end deformation monitoring device, construction method and monitoring method

Abstract

This invention discloses a pre-defined fracture-type pile tip deformation monitoring device, construction method, and monitoring method for driven steel pipe piles. The monitoring device includes a transmission mechanism and a fracture sensor installed at the bottom of the driven pile. The fracture sensor includes a sensing wire, multiple thick shells, and multiple thin shells, which are alternately distributed and connected end-to-end to form a circular portion that matches the inner wall of the driven pile. Each thick shell has a first through hole and a second through hole at its two ends. A resistor is embedded in each thin shell. The sensing wire is connected to both ends of the resistor through the first and second through holes to form independent circuits. All independent circuits are connected in parallel and to the transmission mechanism through corresponding armored wires. This invention has advantages such as economy, convenience, sensitivity, and accuracy. It is suitable for steel pipe pile construction under various geological conditions, effectively improving project quality and reducing engineering risks caused by pile tip deformation.

Description

Technical Field

[0001] This invention relates to the field of pile foundation technology, specifically to a pre-fractured driven steel pipe pile end deformation monitoring device, construction method, and monitoring method. Background Technology

[0002] With the continuous development of the economy, the construction of large-scale buildings and structures near the coast and at sea is increasing, and the geological conditions faced are becoming more complex and diverse. Therefore, the selection of foundation types and construction methods has become particularly important.

[0003] (1) When the geological conditions above the design pile tip elevation are relatively uniform, such as homogeneous or layered sand, clay, strongly weathered rock, or weak rock layers, steel pipe piles have been widely used as a foundation type, and rich experience has been accumulated. By selecting appropriate impact or vibration equipment, steel pipe piles can be successfully driven to the design pile tip elevation to ensure that the expected bearing capacity requirements are met.

[0004] (2) When there are thin layers of hard rock such as moderately weathered, slightly weathered, or unweathered rock, or dense gravel layers above the designed pile tip elevation, it is necessary to conduct a preliminary analysis of the driveability of dynamic pile driving. Based on the analysis results, select appropriate impact or vibration pile driving equipment and its parameters. After driving the steel pipe pile to a certain depth, use a pre-drilling device to remove the soil and rock core inside the pile, and then continue to drive the pile using impact or vibration methods. Repeat this process until the design requirements are met. However, this method mainly relies on specification parameters, individual geological drilling data, and existing engineering experience, and may deviate from the actual site conditions.

[0005] (3) For situations where the soil layer above the designed pile tip elevation is mainly homogeneous or layered, as well as relatively thick moderately weathered rock, slightly weathered rock, or unweathered rock, it is usually necessary to first remove the rock and soil core inside the pile using drilling equipment such as rotary drilling rigs or impact hammers, and then install the reinforcing cage and pour concrete according to the design requirements to form a combined structure of upper steel pipe pile + lower cast-in-place pile or upper steel pipe concrete pile + lower cast-in-place pile.

[0006] Despite detailed feasibility analyses of pile driving, the complex and variable geological conditions make it difficult to fully predict the actual conditions at the construction site. Especially during vibration or impact pile driving, failure to promptly identify geological changes such as moderately weathered rock, slightly weathered rock, unweathered rock, and dense gravel layers can lead to pile tip deformation (commonly known as "edge curling"). This not only affects subsequent pile driving progress but can also cause drill bit jamming, equipment damage, or even safety accidents, ultimately preventing the achievement of the designed pile tip elevation and bearing capacity.

[0007] Based on the above analysis, existing piling technologies and monitoring methods are inadequate when facing complex geological conditions, especially in the timely and accurate identification and response to pile tip deformation. While traditional strain gauges can detect pile tip deformation, their high cost and susceptibility to damage during construction limit their effectiveness in practical engineering applications. Summary of the Invention

[0008] The primary objective of this invention is to overcome the shortcomings of the existing technology and provide a pre-set fracture-type pile tip deformation monitoring device for driven steel pipe piles. This pre-set fracture-type pile tip deformation monitoring device can achieve real-time monitoring of pile tip deformation and has the advantages of economy, convenience, and accuracy, thus ensuring the quality and safety of steel pipe pile driving.

[0009] The second objective of this invention is to provide a construction method for a pre-defined fracture-type driven steel pipe pile end deformation monitoring device.

[0010] The third objective of this invention is to provide a method for monitoring the deformation at the end of driven steel pipe piles.

[0011] The objective of this invention is achieved through the following technical solution: This pre-set fracture-type driven steel pipe pile end deformation monitoring device includes a transmission mechanism and a fracture sensor installed at the bottom end of the driven pile.

[0012] The fracture sensor includes a sensing wire, multiple thick shells and multiple thin shells, which are alternately distributed and connected end to end to form a ring that matches the inner wall of the driven pile. The thick shells have a first through hole and a second through hole at their two ends, respectively. A resistor is embedded in the thin shell. The sensing wire is connected to the two ends of the resistor through the first through hole and the second through hole to form an independent circuit. All the independent circuits are connected in parallel and connected to the transmission mechanism through corresponding armored wires.

[0013] Preferably, the independent circuit is provided with a waterproof insulation layer.

[0014] Preferably, the cross-sections at both ends of the thick shell are V-shaped.

[0015] Preferably, the thin shell has a hollow cavity, and the resistor sheet is fixed in the hollow cavity.

[0016] Preferably, the pre-fractured driven steel pipe pile end deformation monitoring device further includes a protection and fixing mechanism. The protection and fixing mechanism includes a protective cover, a vertical protective shell, and a wire clamp. The protective cover is disposed at the upper end of the fracture sensor, and the lower end of the vertical protective shell is fixed to the protective cover. One end of all armored wires passes through the wire hole of the protective cover and is then fixed inside the protective cover by the wire clamp. One end of each armored wire is connected to an independent circuit, and the other end of the armored wire extends out of the vertical protective shell and is connected to the transmission mechanism.

[0017] Preferably, the transmission mechanism includes a Schmitt trigger, a magnetic ring filter, an opto-isolation module, a demodulator, and a computer. The Schmitt trigger, magnetic ring filter, and opto-isolation module are connected in series. The Schmitt trigger is connected to the independent circuit of the fracture sensor via an armored wire, and the opto-isolation module is connected to the computer via the demodulator.

[0018] The construction method of the pre-set fracture-type driven steel pipe pile end deformation monitoring device based on the first objective includes the following steps:

[0019] S1. Preparation of the fracture sensor: Determine the size and quantity of the thick and thin shells of the fracture sensor according to the inner wall of the driven pile. The thick and thin shells are alternately distributed at the bottom of the driven pile and connected end to end in sequence. The hollow cavity inside the thin shell contains a resistor, and the two ends of the sensing wire pass through the first and second through holes of the thick shell and are connected to the two ends of the resistor to form an independent circuit. At the same time, each independent circuit is connected in parallel through the first armored wire of the armored wire. The resistor and sensing wire in each independent circuit are numbered.

[0020] S2. Installation of the protective fixing mechanism: Install the protective cover on the upper end of the fracture sensor. After each armored wire enters the protective cover through the wire hole, it is fixed by the wire clamp. One end of each armored wire is connected to each independent circuit. At the same time, the other end of each armored wire extends out from the vertical protective shell. Then, fix the fracture sensor with the protective cover to the end of the driven pile, so that the fracture sensor covers the inner wall of the end of the driven pile.

[0021] S3. System Integration: Each armored conductor is routed along the pile body of the driven pile to a certain height through the vertical protective shell, and then fixed to the pile wall of the driven pile by the wire fastener. After reaching a certain height along the pile body, it extends out of the driven pile and is connected in series with Schmitt trigger, magnetic ring filter and opto-isolation module, and finally connected to the computer through demodulator.

[0022] The method for monitoring the deformation at the end of driven steel pipe piles, implemented using the pre-set fracture-type deformation monitoring device for driven steel pipe piles described in the first objective, includes the following steps:

[0023] A1. When the pile tip is not subjected to external force, open the test software on the computer to record the initial resistance value or electrical signal status of each independent circuit as reference data.

[0024] A2. Start the pile driving equipment to begin pile driving operations, monitor the data changes of each independent circuit in real time, and determine the data fluctuations of the independent circuits:

[0025] If the data fluctuation exceeds the set threshold, it indicates that the pile end deformation corresponding to the independent loop is close to the warning value;

[0026] If the data for an independent loop disappears, it indicates that the pile end corresponding to that independent loop has been damaged.

[0027] The present invention has the following advantages over the prior art:

[0028] 1. This invention utilizes a fracture sensor with alternating thick and thin shells arranged circumferentially at the pile end. Each fracture sensor has an independent circuit composed of resistive elements, and these independent circuits are connected in parallel via armored wires. This allows for sensitive reflection of pile end deformation, providing real-time information on pile end deformation for pile driving operations and ensuring the quality and safety of steel pipe pile driving.

[0029] 2. The fracture sensor used in this invention is mainly composed of a resistive element, a thick shell, and a thin shell, which can be easily assembled and installed at the pile end, making construction convenient and ensuring construction efficiency.

[0030] 3. The curvature of the fracture sensor of the present invention is adapted to the inner wall of the pile. Combined with the protective cover and vertical protective shell, it effectively prevents damage caused by non-deformation factors. The wire clamp ensures that the wire is taut and fixed, which improves the accuracy of the fracture sensor detection structure.

[0031] 4. The transmission mechanism of the present invention is composed of a Schmitt trigger, a magnetic ring filter and an opto-isolation module connected in sequence, which improves the signal anti-interference capability and ensures that the data is accurately transmitted to the demodulator and computer.

[0032] 5. This invention can monitor the deformation state of the pile end in real time during the pile driving process, provide timely warnings of abnormal conditions such as pile end curling, guide the dynamic adjustment of pile driving parameters, avoid pile end damage, and ensure the quality and safety of pile driving construction. At the same time, it does not affect subsequent pile pre-hole or drilling operations, and is applicable to engineering fields such as wharves, bridges, and offshore wind power under complex geological conditions. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the pre-fracture type driven steel pipe pile end deformation monitoring device of the present invention.

[0034] Figure 2This is a cross-sectional view of the pre-fracture type driven steel pipe pile end deformation monitoring device of the present invention.

[0035] Figure 3 This is a schematic diagram of the pre-fractured type driven steel pipe pile end deformation monitoring device of the present invention installed at the bottom structure of the driven pile.

[0036] Figure 4 This is a schematic diagram of the connection between the fracture sensor and the protective fixing mechanism of the present invention.

[0037] Figure 5 This is a front view of the connection between the fracture sensor and the protective fixing mechanism of the present invention.

[0038] Figure 6 This is a top view of the fracture sensor of the present invention.

[0039] Among them, 1 is the driven pile, 2 is the fracture sensor, 21 is the sensing wire, 22 is the thick shell, 23 is the thin shell, 24 is the first through hole, 25 is the second through hole, 26 is the resistor, 3 is the armored wire, 4 is the protective fixing mechanism, 41 is the protective cover, 42 is the vertical protective shell, 43 is the wire clamp, 5 is the transmission mechanism, 51 is the Schmitt trigger, 52 is the magnetic ring filter, 53 is the opto-isolation module, 54 is the demodulator, and 55 is the computer. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0041] like Figures 1 to 6 The pre-defined fracture-type driven steel pipe pile end deformation monitoring device shown includes a transmission mechanism and a fracture sensor installed at the bottom of the driven pile. The fracture sensor includes a sensing wire, multiple thick shells and multiple thin shells, which are alternately distributed and connected end to end to form a ring that matches the inner wall of the driven pile. The thick shells have a first through hole and a second through hole at their two ends, respectively. A resistor is embedded in the thin shell. The sensing wire is connected to the two ends of the resistor through the first through hole and the second through hole to form an independent circuit. All the independent circuits are connected in parallel and connected to the transmission mechanism through corresponding armored wires.

[0042] Specifically, the resistors embedded in the thin shell form an independent circuit. This independent circuit, through the annular portion formed by the thick and thin shells, is in contact with the bottom of the pile end. Changes in resistance or electrical signal state along this independent circuit reflect the deformation of the corresponding element at the pile end. This allows for real-time monitoring of pile end deformation during pile driving, providing crucial assurance for construction quality and safety, effectively improving project quality, and reducing engineering risks caused by pile end deformation. The thick shell has a first through hole and a second through hole at both ends to facilitate the connection of the sensing wires to the resistors, thus forming an independent circuit for monitoring pile end deformation. This simplifies the placement of the resistors, improves the compactness of the fracture sensor, and further enhances construction convenience. The number and size of the thick and thin shells in this embodiment can be determined based on the parameters of the pile end, ensuring that the annular portion formed by the thick and thin shells fits tightly against the inner wall of the pile end.

[0043] The independent circuit is equipped with a waterproof insulation layer. The waterproof insulation layer ensures that the independent circuit composed of resistors and other components has good performance, thereby further guaranteeing the sensitivity and accuracy of the detection.

[0044] The thick shell has V-shaped cross-sections at both ends. The V-shaped cross-section design enhances structural stability and signal reliability.

[0045] The thin shell has a hollow cavity, and the resistive element is fixed inside the hollow cavity. The hollow cavity facilitates the placement of the resistive element and improves operational convenience.

[0046] The pre-set fracture-type driven steel pipe pile end deformation monitoring device further includes a protective fixing mechanism. This mechanism comprises a protective cover, a vertical protective shell, and a wire clamp. The protective cover is positioned above the fracture sensor, and the lower end of the vertical protective shell is fixed to the protective cover. One end of each armored wire passes through a through-hole in the protective cover and is then fixed inside the cover by the wire clamp. Each armored wire has one end connected to an independent circuit, and the other end extends out of the vertical protective shell and connects to the transmission mechanism. This protective fixing mechanism effectively prevents damage caused by non-deformation factors, further improving the accuracy of the fracture sensor. Simultaneously, the wire clamp ensures the wires are taut and fixed, thereby enhancing the sensitivity of the fracture sensor.

[0047] The transmission mechanism includes a Schmitt trigger, a magnetic ring filter, an opto-isolation module, a demodulator, and a computer. The Schmitt trigger, magnetic ring filter, and opto-isolation module are connected in series. The Schmitt trigger is connected to the independent circuit of the fracture sensor via armored wires, and the opto-isolation module is connected to the computer via the demodulator. Specifically, in this embodiment, the Schmitt trigger suppresses instantaneous on / off jitter caused by construction vibration, the magnetic ring filter filters out high-frequency electromagnetic interference generated by hammering, and the opto-isolation module cuts off the ground loop to avoid common-mode noise, thereby further improving the accuracy of detection. The opto-isolation module in this embodiment is a mature opto-isolation device based on an optocoupler. To ensure monitoring accuracy, the opto-isolation module in this embodiment uses mature industrial-grade opto-isolation products, such as, but not limited to, Texas Instruments' ISO7840 series and Silicon Labs' Si86xx series digital isolators. These isolators provide isolation voltages up to 5000Vrms or even higher, fully meeting the stringent electrical environment requirements of piling sites and effectively preventing high-voltage surges from damaging downstream monitoring equipment.

[0048] The construction method of the pre-set fracture-type driven steel pipe pile end deformation monitoring device based on the first objective includes the following steps:

[0049] S1. Preparation of the fracture sensor: Determine the size and quantity of the thick and thin shells of the fracture sensor according to the inner wall of the driven pile. The thick and thin shells are alternately distributed at the bottom of the driven pile and connected end to end in sequence. The hollow cavity inside the thin shell contains a resistor, and the two ends of the sensing wire pass through the first and second through holes of the thick shell and are connected to the two ends of the resistor to form an independent circuit. At the same time, each independent circuit is connected in parallel through the first armored wire of the armored wire. The resistor and sensing wire in each independent circuit are numbered.

[0050] S2. Installation of the protective fixing mechanism: Install the protective cover on the upper end of the fracture sensor. After each armored wire enters the protective cover through the wire hole, it is fixed by the wire clamp. One end of each armored wire is connected to each independent circuit. At the same time, the other end of each armored wire extends out from the vertical protective shell. Then, fix the fracture sensor with the protective cover to the end of the driven pile, so that the fracture sensor covers the inner wall of the end of the driven pile.

[0051] S3. System Integration: Each armored conductor is routed along the pile body of the driven pile to a certain height through the vertical protective shell, and then fixed to the pile wall of the driven pile by the wire fastener. After reaching a certain height along the pile body, it extends out of the driven pile and is connected in series with Schmitt trigger, magnetic ring filter and opto-isolation module, and finally connected to the computer through demodulator.

[0052] The method for monitoring the deformation at the end of driven steel pipe piles, implemented using the pre-set fracture-type deformation monitoring device for driven steel pipe piles described in the first objective, includes the following steps:

[0053] A1. When the pile tip is not subjected to external force, open the test software on the computer to record the initial resistance value or electrical signal status of each independent circuit as reference data.

[0054] A2. Start the pile driving equipment to begin pile driving operations, monitor the data changes of each independent circuit in real time, and determine the data fluctuations of the independent circuits:

[0055] If the data fluctuation exceeds the set threshold, it indicates that the pile end deformation corresponding to the independent loop is close to the warning value. In this case, the pile driving rate should be appropriately reduced and the monitoring should be strengthened.

[0056] If data from an independent loop disappears, it indicates that the pile end corresponding to that loop has been damaged. Pile driving should be stopped immediately, and an assessment should be made to determine if remedial measures are necessary. After pile driving is completed, the monitoring device in this embodiment can continue to monitor the subsequent bearing status of the pile end for a long period of time to ensure the safe use of the steel pipe pile.

[0057] The pre-fracture type driven steel pipe pile end deformation monitoring device, construction method and monitoring method of this application are applicable to steel pipe pile construction under various geological conditions, which can effectively improve the quality of the project and reduce the project risks caused by pile end deformation.

[0058] The above-described specific embodiments are preferred embodiments of the present invention and are not intended to limit the present invention. Any other changes or equivalent substitutions made without departing from the technical solution of the present invention are included within the protection scope of the present invention.

Claims

1. A pre-set fracture-type driven steel pipe pile end deformation monitoring device, characterized in that, This includes a transmission mechanism and a fracture sensor installed at the bottom of the driven pile; The fracture sensor includes a sensing wire, multiple thick shells and multiple thin shells, which are alternately distributed and connected end to end to form a ring that matches the inner wall of the driven pile. The thick shells have a first through hole and a second through hole at their two ends, respectively. A resistor is embedded in the thin shell. The sensing wire is connected to the two ends of the resistor through the first through hole and the second through hole to form an independent circuit. All the independent circuits are connected in parallel and connected to the transmission mechanism through corresponding armored wires.

2. The pre-fracture type driven steel pipe pile end deformation monitoring device according to claim 1, characterized in that, The independent circuit is equipped with a waterproof insulation layer.

3. The pre-fracture type driven steel pipe pile end deformation monitoring device according to claim 1, characterized in that, The cross-sections at both ends of the thick shell are V-shaped.

4. The pre-fractured driven steel pipe pile end deformation monitoring device according to claim 1, characterized in that, The thin shell has a hollow cavity, and the resistor is fixed in the hollow cavity.

5. The pre-fracture type driven steel pipe pile end deformation monitoring device according to claim 1, characterized in that, It also includes a protective fixing mechanism, which includes a protective cover, a vertical protective shell, and a wire clamp. The protective cover is located at the upper end of the fracture sensor, and the lower end of the vertical protective shell is fixed to the protective cover. One end of all the armored wires passes through the wire hole of the protective cover and is then fixed inside the protective cover by the wire clamp. One end of each armored wire is connected to an independent circuit, and the other end of the armored wire extends out of the vertical protective shell and is connected to the transmission mechanism.

6. The pre-fracture type driven steel pipe pile end deformation monitoring device according to claim 1, characterized in that, The transmission mechanism includes a Schmitt trigger, a magnetic ring filter, an opto-isolation module, a demodulator, and a computer. The Schmitt trigger, magnetic ring filter, and opto-isolation module are connected in series. The Schmitt trigger is connected to the independent circuit of the fracture sensor through an armored wire. The opto-isolation module is connected to the computer through the demodulator.

7. A construction method for a pre-set fracture-type driven steel pipe pile end deformation monitoring device according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Preparation of the fracture sensor: Determine the size and quantity of the thick and thin shells of the fracture sensor according to the inner wall of the driven pile. The thick and thin shells are alternately distributed at the bottom of the driven pile and connected end to end in sequence. The hollow cavity inside the thin shell contains a resistor, and the two ends of the sensing wire pass through the first and second through holes of the thick shell and are connected to the two ends of the resistor to form an independent circuit. At the same time, each independent circuit is connected in parallel through the first armored wire of the armored wire. The resistor and sensing wire in each independent circuit are numbered. S2. Installation of the protective fixing mechanism: Install the protective cover on the upper end of the fracture sensor. After each armored wire enters the protective cover through the wire hole, it is fixed by the wire clamp. One end of each armored wire is connected to each independent circuit. At the same time, the other end of each armored wire extends out from the vertical protective shell. Then, fix the fracture sensor with the protective cover to the end of the driven pile, so that the fracture sensor covers the inner wall of the end of the driven pile. S3. System Integration: Each armored conductor is routed along the pile body of the driven pile to a certain height through the vertical protective shell, and then fixed to the pile wall of the driven pile by the wire fastener. After reaching a certain height along the pile body, it extends out of the driven pile and is connected in series with Schmitt trigger, magnetic ring filter and opto-isolation module, and finally connected to the computer through demodulator.

8. A method for monitoring the deformation at the end of driven steel pipe piles, characterized in that, The method employs the pre-fractured, driven steel pipe pile end deformation monitoring device as described in any one of claims 1 to 5, comprising the following steps: A1. When the pile tip is not subjected to external force, open the test software on the computer to record the initial resistance value or electrical signal status of each independent circuit as reference data. A2. Start the pile driving equipment to begin pile driving operations, monitor the data changes of each independent circuit in real time, and determine the data fluctuations of the independent circuits: If the data fluctuation exceeds the set threshold, it indicates that the pile end deformation corresponding to the independent loop is close to the warning value; If the data for an independent loop disappears, it indicates that the pile end corresponding to that independent loop has been damaged.

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