A method for measuring penetration and rebound value of hammer pile

Abstract

The invention discloses a method for measuring the penetration degree and rebound value of a hammer pile, comprising a liquid storage tank, a reference point sensor, a measuring point sensor, a pile driver, a plurality of liquid pipes and a plurality of air pipes; both ends of the reference point sensor are provided with a plurality of exhaust holes one, an air pipe interface one and a liquid pipe interface one, the two air pipe interfaces one are internally connected, and the two liquid pipe interfaces one are internally connected; both ends of the measuring point sensor are provided with a plurality of exhaust holes two, an air pipe interface two and a liquid pipe interface two, the two air pipe interfaces two are internally connected, and the two liquid pipe interfaces two are internally connected; the air pipe and the liquid pipe connecting the liquid storage tank and the reference point sensor are respectively connected with the air pipe interface one and the liquid pipe interface one at one end of the reference point sensor; the penetration degree and rebound value of the hammer pile can be accurately measured in a safe and reliable manner.

Description

Technical Field

[0001] The invention relates to the technical field of civil construction, in particular to a method for determining the penetration and rebound value of a hammer pile. Background Art

[0002] In the process of pile foundation construction and design, the penetration of hammer piles is a very important indicator for evaluating the bearing capacity of piles. The Hilly formula in the dynamic pile driving formula is widely used in international engineering projects.

[0003] The Hilly formula is based on the theory of conservation of energy and elastic collision. It equates the energy of the hammer with the work done to overcome the resistance of the ground to the penetrating pile. It then considers factors such as the energy loss caused by the elastic contraction of the pile and soil layer, and the energy loss due to the inelastic deformation of the pile and soil.

[0004] In the traditional piling process, both at home and abroad, there are usually two methods for measuring penetration:

[0005] Method 1: Use a T-square against the pile body (or pile driver), draw a line every 10 blows, and then use a steel ruler to measure the distance to obtain the penetration degree of each array.

[0006] Method 2: stick a ruler scale on the pile body (or pile driver), use a level to read the numbers at a distance, and also read the numbers every 10 blows to get the penetration degree of each array.

[0007] The obvious characteristics of the traditional method are that the penetration measurement accuracy is not high and is greatly affected by human factors; it can only measure the penetration but not the rebound value; the calculation process often uses empirical coefficients for estimation, so the calculation results are extremely inaccurate. And when using method 1 for measurement, workers need to operate under the impact of a heavy hammer, which poses a serious safety hazard. Summary of the invention

[0008] Based on the above problems existing in the prior art, an object of an embodiment of the present invention is to provide a method for measuring the penetration degree and rebound value of a hammer pile, which can accurately measure the penetration degree and rebound value of a hammer pile in a safe and reliable manner.

[0009] The technical solution adopted by the present invention to solve the technical problem is: a device for measuring the penetration and rebound value of a hammer pile, comprising a liquid storage tank, a reference point sensor, a measuring point sensor, a pile driver, a plurality of liquid pipes and a plurality of air pipes;

[0010] Both ends of the reference point sensor are provided with a plurality of exhaust holes 1, an air pipe interface 1 and a liquid pipe interface 1, the two air pipe interfaces 1 are internally connected, and the two liquid pipe interfaces 1 are internally connected;

[0011] Both ends of the measuring point sensor are provided with a plurality of exhaust holes 2, a gas pipe interface 2 and a liquid pipe interface 2, the two gas pipe interfaces 2 are internally connected, and the two liquid pipe interfaces 2 are internally connected;

[0012] The air pipe and the liquid pipe connecting the liquid storage tank and the reference point sensor are respectively connected to the air pipe interface 1 and the liquid pipe interface 1 at one end of the reference point sensor;

[0013] One end of the air pipe and the liquid pipe connected to the reference point sensor and the measuring point sensor are respectively docked with the air pipe interface 1 and the liquid pipe interface 1 at the other end of the reference point sensor, and the other end of the air pipe and the liquid pipe are respectively docked with the air pipe interface 2 and the liquid pipe interface 2 at one end of the measuring point sensor;

[0014] The measuring point sensor is provided with an air pipe plug on the air pipe interface 2 at the end of the air pipe and the liquid pipe connected thereto, and the measuring point sensor is provided with a liquid pipe plug on the liquid pipe interface 2 at the end of the air pipe and the liquid pipe connected thereto;

[0015] A connecting base is fixed on the pile driver, and the measuring point sensor is fixed on the connecting base.

[0016] Furthermore, it also includes a gateway and a plurality of communication lines, wherein the gateway and the reference point sensor are connected by the communication lines, and the reference point sensor and the measuring point sensor are connected by the communication lines.

[0017] Furthermore, the gateway is configured with a displacement conversion strategy and a data processing strategy;

[0018] The displacement conversion strategy includes obtaining the pressure P0 measured by the reference point sensor, the pressure P1 measured by the measuring point sensor, and the density of the liquid in the liquid pipe, and substituting the obtained pressure P0 measured by the reference point sensor, the pressure P1 measured by the measuring point sensor, and the density of the liquid in the liquid pipe into the liquid pressure formula to convert the initial height difference D0 of the measuring point sensor relative to the reference point sensor, and the height difference D1 of the measuring point sensor relative to the reference point sensor after the measuring point sensor is displaced, and the displacement conversion formula is configured in the displacement conversion strategy;

[0019] The displacement conversion formula is:

[0020] D=D 1测 -D1

[0021] Where D is the relative displacement distance of the measuring point sensor;

[0022] The data processing strategy includes setting a data collection interval, and drawing a displacement time curve according to the time data and displacement data collected at multiple time points during the data collection interval.

[0023] Furthermore, the liquid level in the liquid storage tank is 2 / 3 of the height.

[0024] The present invention also discloses an assembly method for assembling a device for measuring the penetration and rebound value of a hammer pile. The assembly steps are as follows:

[0025] A1. Fix the reference point sensor at a location far away from the construction area and not affected by construction vibration;

[0026] A2, fixing the connection base on the pile driver;

[0027] A3. The liquid storage tank is set near the reference point sensor and is higher than the reference point sensor;

[0028] A4. Connect the gateway and the reference sensor with the communication line, and connect the reference sensor and the measuring point sensor with the communication line. Power on and check whether the communication is normal. If the communication is abnormal, recheck it. If the communication is normal, proceed to the next step.

[0029] A5. Connect the liquid storage tank to the reference sensor, and the reference sensor to the measuring point sensor with air pipes and liquid pipes;

[0030] A6. Move the measuring point sensor to a position lower than the reference point sensor, open the liquid pipe plug, and pump the filling liquid into the second liquid pipe interface connected to the liquid pipe plug until the liquid level in the liquid storage tank reaches no less than 50% of the height, then stop pumping the filling liquid, and plug the liquid pipe plug onto the second liquid pipe interface again;

[0031] A7. After filling the liquid, check the exhaust hole 1 of the reference sensor and the exhaust hole 2 of the measuring point sensor to ensure that the exhaust is sufficient and there are no bubbles in the liquid pipe, the reference sensor and the measuring point sensor;

[0032] A8. When the pile driving is in the pile delivery stage, install the pile driver, and then stop the pile delivery when the pile driver delivers the pile until the elevation of the connection base is close to the elevation of the reference point sensor. Fix the measuring point sensor on the connection base to ensure that the connection between the measuring point sensor and the connection base is firm. Check again whether there are bubbles in the liquid pipe, reference sensor and measuring point sensor. If there are bubbles, they can be discharged through the sensor exhaust hole.

[0033] Further, B1, set the time interval for the gateway to collect data to 0.1 seconds;

[0034] B2. Export the gateway data and draw a displacement time curve based on the data exported by the gateway;

[0035] B3. Obtain the peak value in the displacement time curve, calculate the difference between adjacent peak values, and obtain the penetration S of each hammer pile;

[0036] B4. Obtain the peak value and trough value in the displacement time curve, make the difference between the adjacent peak values ​​and trough values, and obtain the rebound value CP of the pile and pile driver and the rebound value Cq of the soil layer under each impact. Sum CP and Cq to obtain the rebound value C of the hammer pile.

[0037] Furthermore, the measured penetration of each hammer pile and the rebound value of each hammer pile are substituted into the Hilly formula, and the ultimate bearing capacity of the pile is calculated according to the Hilly formula. The Hilly formula is:

[0038] R=ξWh / (S+C / 2)

[0039] Among them, R is the ultimate bearing capacity of the pile, W is the weight of the hammer, h is the jumping height or free falling height of the hammer, and ξ is the drop hammer efficiency reduction coefficient. When the hammer is an ideal free falling hammer, ξ=1, and when it is a non-free falling hammer, ξ<1.

[0040] Furthermore, the application of the determination method of the penetration and rebound value of the hammer pile in the Healy formula combines the determination method of the penetration and rebound value of the hammer pile, the Healy formula and the impact energy transmitted to the pile top measured by the PDA dynamic detection technology to obtain a more accurate calculation method for the ultimate bearing capacity of the pile. The combined calculation formula is:

[0041] R=Ea / (S+C / 2)

[0042] Among them, Ea is the impact energy transmitted to the top of the pile measured by PDA dynamic detection technology.

[0043] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0044] 1. The measurement process is fully automatically recorded, not affected by human factors, and the data is relatively reliable;

[0045] 2. The reference sensor is arranged at a relatively far place, which is less affected by the vibration of the construction site and is more reliable;

[0046] 3. The data collection process is safer;

[0047] 4. The amount of data is large, and the array analysis results formed can better reflect the changes in the construction process. The curve state obtained is credible, and a large amount of data can also assist in analyzing the hammer energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0049] In the figure:

[0050] Figure 1 It is a schematic diagram of the structure of the measuring device in the present invention;

[0051] Figure 2 It is a schematic diagram of the displacement time curve in the present invention. DETAILED DESCRIPTION

[0052] The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the present invention in a schematic manner, and therefore only shows the components related to the present invention.

[0053] See also Figure 1-2 , the present invention provides a technical solution:

[0054] A device for measuring penetration and rebound value of hammer piles comprises a liquid storage tank, a reference point sensor, a measuring point sensor, a pile driver, a plurality of liquid pipes, a plurality of air pipes, a gateway and a plurality of communication lines.

[0055] One end of the liquid storage tank away from the ground is connected to the reference point sensor via an air pipe, and one end of the liquid storage tank close to the ground is connected to the reference point sensor via a liquid pipe.

[0056] The reference point sensor and the measuring point sensor are interconnected by a liquid pipe and a gas pipe.

[0057] Both ends of the reference point sensor are provided with a plurality of exhaust holes, an air pipe interface and a liquid pipe interface. The two air pipe interfaces are internally connected, and the two liquid pipe interfaces are internally connected.

[0058] The air pipe and liquid pipe connecting the liquid storage tank and the reference point sensor are respectively connected to the air pipe interface 1 and the liquid pipe interface 1 at one end of the reference point sensor.

[0059] A connecting base is fixed on the pile driver, and a measuring point sensor is fixed on the connecting base.

[0060] Both ends of the measuring point sensor are provided with a plurality of exhaust holes 2, a gas pipe interface 2 and a liquid pipe interface 2. The two gas pipe interfaces 2 are internally connected, and the two liquid pipe interfaces 2 are internally connected.

[0061] One end of the air pipe and liquid pipe connecting the reference point sensor and the measuring point sensor are respectively docked with the air pipe interface 1 and the liquid pipe interface 1 at the other end of the reference point sensor, and the other end of the air pipe and the liquid pipe are respectively docked with the air pipe interface 2 and the liquid pipe interface 2 at one end of the measuring point sensor.

[0062] In some of the embodiments, the reference point sensor and the measuring point sensor are preferably differential pressure dynamic levels, which can measure pressure data with high accuracy.

[0063] An air pipe plug is provided on the air pipe interface 2 of the measuring point sensor away from the end of the air pipe and liquid pipe docked therewith, and a liquid pipe plug is provided on the liquid pipe interface 2 of the measuring point sensor away from the end of the air pipe and liquid pipe docked therewith.

[0064] The gateway and the reference point sensor are connected by a communication line, and the reference point sensor and the measuring point sensor are connected by a communication line.

[0065] The gateway is configured with displacement conversion strategy and data processing strategy.

[0066] The displacement conversion strategy includes obtaining the pressure P0 measured by the reference point sensor, the pressure P1 measured by the measuring point sensor, and the density of the liquid in the liquid pipe, and substituting the obtained pressure P0 measured by the reference point sensor, the pressure P1 measured by the measuring point sensor, and the density of the liquid in the liquid pipe into the liquid pressure formula to convert the initial height difference D0 of the measuring point sensor relative to the reference point sensor, the height difference D0 of the measuring point sensor relative to the reference point sensor after the measuring point sensor is displaced, and the height difference D0 of the measuring point sensor relative to the reference point sensor. 1测 .

[0067] The displacement conversion formula is:

[0068] D=D 1测 -D1

[0069] Where D is the relative displacement distance of the measuring point sensor.

[0070] The data processing strategy includes setting a data collection interval and drawing a displacement time curve based on the time data and displacement data collected at multiple time points during the data collection interval.

[0071] The process of the measuring device measuring the penetration depth and rebound value of the hammer pile is fully automatically recorded and is not affected by human factors. The data is relatively reliable. This automated recording method does not require manual operation and has a high safety factor.

[0072] An assembly method for a device for measuring penetration and rebound value of a hammer pile, the assembly steps are as follows:

[0073] A1. Fix the reference point sensor at a location far away from the construction area and not affected by construction vibration;

[0074] A2. Fix the connection base on the pile driver;

[0075] A3. The liquid storage tank is set near the reference point sensor and is higher than the reference point sensor;

[0076] A4. Connect the gateway and the reference sensor with the communication line, and connect the reference sensor and the measuring point sensor with the communication line. Power on and check whether the communication is normal. If the communication is abnormal, recheck it. If the communication is normal, proceed to the next step.

[0077] A5. Connect the liquid storage tank to the reference sensor, and the reference sensor to the measuring point sensor with air pipes and liquid pipes;

[0078] A6. Move the measuring point sensor to a position lower than the reference point sensor, open the liquid pipe plug, and pump the filling liquid into the second liquid pipe interface connected to the liquid pipe plug until the liquid level in the liquid storage tank reaches no less than 50% of the height. Stop pumping the filling liquid. The liquid level in the liquid storage tank is preferably 2 / 3 of the height, and plug the liquid pipe plug on the second liquid pipe interface again.

[0079] A7. After filling the liquid, check the exhaust hole 1 of the reference sensor and the exhaust hole 2 of the measuring point sensor to ensure that the exhaust is sufficient and there are no bubbles in the liquid pipe, the reference sensor and the measuring point sensor;

[0080] A8. When the pile driving is in the pile delivery stage, install the pile driver, and then stop the pile delivery when the pile driver delivers the pile until the elevation of the connection base is roughly close to the elevation of the reference point sensor. Fix the measuring point sensor on the connection base to ensure that the connection between the measuring point sensor and the connection base is firm. Check again whether there are bubbles in the liquid pipe, reference sensor and measuring point sensor. If there are bubbles, they can be discharged through the sensor exhaust hole.

[0081] The reference point sensor is far away from the construction area and is not affected by the vibration of the construction area. The measured pressure data is more accurate.

[0082] The liquid storage tank is set higher than the reference point sensor to ensure that when the pile is delivered, the reference point sensor, the measuring point sensor and the liquid pipe are filled with filling liquid to avoid bubbles in the reference point sensor, the measuring point sensor and the liquid pipe. The measuring device assembled in this way has higher accuracy.

[0083] In some of these embodiments, the filling fluid may be antifreeze fluid.

[0084] The liquid level in the liquid storage tank is preferably 2 / 3 of the height to ensure that the height of the measuring point sensor is not higher than the liquid level in the liquid storage tank when the pile driver moves, to avoid bubbles in the measuring point sensor, and to increase the accuracy of the measuring device.

[0085] Repeatedly checking the presence of bubbles in the liquid pipe, reference sensor and measuring point sensor can also improve the accuracy of the measuring device in measuring the penetration and rebound value of the hammer pile.

[0086] A method for determining the penetration and rebound value of hammer piles:

[0087] B1. Set the time interval for gateway data collection, preferably 0.1 seconds;

[0088] B2. Export the gateway data and draw a displacement time curve based on the data exported by the gateway;

[0089] B3. Obtain the peak value in the displacement time curve, calculate the difference between adjacent peak values, and obtain the penetration S of each hammer pile;

[0090] B4. Obtain the peak value and trough value in the displacement time curve, make the difference between the adjacent peak values ​​and trough values, and obtain the rebound value C of the pile and pile driver under each impact. P , the rebound value C of the soil layer q , C P and C q Add the values ​​and we get the rebound value C of the hammer pile.

[0091] The application of the method for determining the penetration and rebound value of hammer piles in the Healy formula is characterized in that the measured penetration and rebound value of hammer piles are substituted into the Healy formula, and the ultimate bearing capacity of the pile is calculated according to the Healy formula. The Healy formula is:

[0092] R=ξWh / (S+C / 2)

[0093] Where R is the ultimate bearing capacity of the pile, W is the weight of the hammer, h is the jump height or free fall height of the hammer, ξ is the drop hammer efficiency reduction coefficient. When the hammer is an ideal free fall hammer, ξ=1, when it is a non-free fall hammer, ξ<1, S is the penetration rate of the hammer pile, and C is the rebound value of each hammer pile.

[0094] In some of the embodiments, the gateway may be connected to a device such as a computer (not shown), and the data exported by the gateway may be uploaded to the computer, and the computer may draw a displacement time curve based on the data exported by the gateway.

[0095] By drawing the displacement-time curve, we can intuitively understand the trend of pile displacement distance changing with time, and conveniently calculate the penetration and rebound value of the hammer pile.

[0096] In some embodiments, a pile cap is provided on the pile, and the calculation formula of the rebound value C of each hammer hitting the pile is:

[0097] C=C p +C q +C c

[0098] Among them, C C is the pile cap rebound value, pile cap rebound value C C As shown in the following table:

[0099]

[0100] The application of the method for determining the penetration and rebound value of hammer piles in the Healy formula is characterized in that the measured penetration and rebound value of hammer piles are substituted into the Healy formula, and the ultimate bearing capacity of the pile is calculated according to the Healy formula. The Healy formula is:

[0101] R=ξWhη / (S+C / 2)

[0102] Where R is the ultimate bearing capacity of the pile, W is the weight of the hammer, h is the jump height or free fall height of the hammer, ξ is the drop hammer efficiency reduction coefficient, when the hammer is an ideal free fall hammer, ξ = 1, when it is a non-free fall hammer, ξ < 1, S is the penetration of the hammer pile, C is the rebound value of the hammer pile, and η is the efficiency of the impact, that is, the energy actually hammered onto the pile and the energy contained in the hammer under ideal conditions.

[0103] The calculation formula of η is as follows:

[0104] When η≥Pe, η=(W+Pe 2 ) / (W+P);

[0105] When η<Pe, η=(W+Pe 2 ) / (W+P)-[(W-Pe) / (W+P)] 2

[0106] P is the sum of the weights of the non-impacting parts of the pile, anvil, pile driver and hammer; e is the coefficient of restitution of the striking material as shown in the following table:

[0107]

[0108] A more accurate ultimate bearing capacity of piles can be calculated.

[0109] Combining the determination method of hammer pile penetration and rebound value, the Hilly formula and the impact energy transmitted to the pile top measured by PDA dynamic detection technology, a more accurate calculation method for the ultimate bearing capacity of the pile is obtained. The combined calculation formula is:

[0110] R=Ea / (S+C / 2)

[0111] Among them, Ea is the impact energy transmitted to the top of the pile measured by PDA dynamic detection technology.

[0112] The ultimate bearing capacity of the pile can be calculated more accurately, which provides a method for more accurately calculating the ultimate bearing capacity of the hammer pile.

[0113] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the scope of the present invention through the above description. The technical scope of this invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A device for measuring penetration and rebound value of hammer piles, characterized in that: It includes a liquid storage tank, a reference point sensor, a measuring point sensor, a pile driver, a plurality of liquid pipes and a plurality of air pipes; Both ends of the reference point sensor are provided with a plurality of exhaust holes 1, an air pipe interface 1 and a liquid pipe interface 1, the two air pipe interfaces 1 are internally connected, and the two liquid pipe interfaces 1 are internally connected; Both ends of the measuring point sensor are provided with a plurality of exhaust holes 2, a gas pipe interface 2 and a liquid pipe interface 2, the two gas pipe interfaces 2 are internally connected, and the two liquid pipe interfaces 2 are internally connected; The air pipe and the liquid pipe connecting the liquid storage tank and the reference point sensor are respectively connected to the air pipe interface 1 and the liquid pipe interface 1 at one end of the reference point sensor; One end of the air pipe and the liquid pipe connected to the reference point sensor and the measuring point sensor are respectively docked with the air pipe interface 1 and the liquid pipe interface 1 at the other end of the reference point sensor, and the other end of the air pipe and the liquid pipe are respectively docked with the air pipe interface 2 and the liquid pipe interface 2 at one end of the measuring point sensor; The measuring point sensor is provided with an air pipe plug on the air pipe interface 2 at the end of the air pipe and the liquid pipe connected thereto, and the measuring point sensor is provided with a liquid pipe plug on the liquid pipe interface 2 at the end of the air pipe and the liquid pipe connected thereto; A connecting base is fixed on the pile driver, and the measuring point sensor is fixed on the connecting base.

2. A device for measuring penetration and rebound value of hammer pile according to claim 1, characterized in that: It also includes a gateway and a plurality of communication lines. The gateway and the reference point sensor are connected by the communication lines, and the reference point sensor and the measuring point sensor are connected by the communication lines.

3. A device for measuring penetration and rebound value of hammer pile according to claim 2, characterized in that: The gateway is configured with a displacement conversion strategy and a data processing strategy; The displacement conversion strategy includes obtaining the pressure P0 measured by the reference point sensor, the pressure P1 measured by the measuring point sensor, and the density of the liquid in the liquid pipe, and substituting the obtained pressure P0 measured by the reference point sensor, the pressure P1 measured by the measuring point sensor, and the density of the liquid in the liquid pipe into the liquid pressure formula to convert the initial height difference D0 of the measuring point sensor relative to the reference point sensor, the height difference D0 of the measuring point sensor relative to the reference point sensor after the measuring point sensor is displaced, and the height difference D0 of the measuring point sensor relative to the reference point sensor. 1测 , the displacement conversion strategy is configured with a displacement conversion formula; The displacement conversion formula is: D=D 1测 -D1 Where D is the relative displacement distance of the measuring point sensor; The data processing strategy includes setting a data collection interval, and drawing a displacement time curve according to the time data and displacement data collected at multiple time points during the data collection interval.

4. A device for measuring penetration and rebound value of hammer pile according to claim 1, characterized in that: The liquid level in the liquid storage tank is 2 / 3 of the height.

5. An assembly method, using a device for measuring penetration and rebound value of a hammer pile according to any one of claims 1 to 4, characterized in that: The assembly steps are as follows: A1. Fix the reference point sensor at a location far away from the construction area and not affected by construction vibration; A2, fixing the connection base on the pile driver; A3. The liquid storage tank is set near the reference point sensor and is higher than the reference point sensor; A4. Connect the gateway and the reference sensor with the communication line, and connect the reference sensor and the measuring point sensor with the communication line. Power on and check whether the communication is normal. If the communication is abnormal, recheck it. If the communication is normal, proceed to the next step. A5. Connect the liquid storage tank to the reference sensor, and the reference sensor to the measuring point sensor with air pipes and liquid pipes; A6. Move the measuring point sensor to a position lower than the reference point sensor, open the liquid pipe plug, and pump the filling liquid into the second liquid pipe interface connected to the liquid pipe plug until the liquid level in the liquid storage tank reaches no less than 50% of the height, then stop pumping the filling liquid, and plug the liquid pipe plug onto the second liquid pipe interface again; A7. After filling the liquid, check the exhaust hole 1 of the reference sensor and the exhaust hole 2 of the measuring point sensor to ensure that the exhaust is sufficient and there are no bubbles in the liquid pipe, the reference sensor and the measuring point sensor; A8. When the pile driving is in the pile delivery stage, install the pile driver, and then stop the pile delivery when the pile driver delivers the pile until the elevation of the connection base is close to the elevation of the reference point sensor. Fix the measuring point sensor on the connection base to ensure that the connection between the measuring point sensor and the connection base is firm. Check again whether there are bubbles in the liquid pipe, reference sensor and measuring point sensor. If there are bubbles, they can be discharged through the sensor exhaust hole.

6. An assembly method according to claim 5, characterized in that: B1. Set the gateway to collect data at a time interval of 0.1 seconds; B2. Export the gateway data and draw a displacement time curve based on the data exported by the gateway; B3. Obtain the peak value in the displacement time curve, calculate the difference between adjacent peak values, and obtain the penetration S of each hammer pile; B4. Obtain the peak value and trough value in the displacement time curve, make the difference between the adjacent peak values ​​and trough values, and obtain the rebound value C of the pile and pile driver under each impact. P , the rebound value C of the soil layer q , C P and C q Add the values ​​and we get the rebound value C of the hammer pile.

7. An assembly method according to claim 6, characterized in that: Substitute the calculated penetration of each hammer pile and the rebound value of each hammer pile into the Hilly formula, and calculate the ultimate bearing capacity of the pile based on the Hilly formula. The Hilly formula is: R=ξWh / (S+C / 2) Among them, R is the ultimate bearing capacity of the pile, W is the weight of the hammer, h is the jumping height or free falling height of the hammer, and ξ is the drop hammer efficiency reduction coefficient. When the hammer is an ideal free falling hammer, ξ=1, and when it is a non-free falling hammer, ξ<1.

8. An assembly method according to claim 7, characterized in that: Combining the determination method of hammer pile penetration and rebound value, the Hilly formula and the impact energy transmitted to the pile top measured by PDA dynamic detection technology, a more accurate calculation method for the ultimate bearing capacity of the pile is obtained. The combined calculation formula is: R=Ea / (S+C / 2) Among them, Ea is the impact energy transmitted to the top of the pile measured by PDA dynamic detection technology.

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