CN207228185U - Open-end PHC tubular pile end resistance testing device - Google Patents

Abstract

The utility model belongs to the technical field of foundation engineering, and relates to an open-end type PHC pipe pile end resistance test device, the base steel plate and the circular steel plate at the end of the pipe pile are welded together; a sensor is reserved on the base steel plate Embedding hole and traction groove; the temperature self-compensating fiber grating earth pressure sensor is installed in the sensor embedding hole, the bottom and side of the temperature self-compensating fiber grating earth pressure sensor are closely pasted with the pipe pile with planting glue, and the armored optical cable passes through the base The traction groove on the steel plate leads from the inner wall groove of the pipe pile to the outer wall groove of the pipe pile through the first borehole of the pile body, and then leads out from the inside of the pipe pile through the second borehole of the pile body to connect with the fiber grating analyzer; its structure Simple, easy to install, easy to operate, low cost, not easy to damage, high test accuracy, strong operability, capable of real-time monitoring and long-term monitoring, wide application, and can also be applied to other types of prefabricated piles.

Description

An open-ended PHC pipe pile end resistance test device

Technical field:

The utility model belongs to the technical field of foundation engineering, and relates to a test device for pile end resistance of prefabricated piles, in particular to an end open type PHC (Prestress High Concrete, Prestress High Concrete) pipe pile end resistance test device .

Background technique:

Pile foundation is a foundation form with a long history, and it is also a widely used building foundation form. With the acceleration of the urbanization process, the scale of buildings continues to increase, and the building structure is becoming more and more "tall, refined, and sharp". In addition, the soil layer is complex, and the requirements for building foundations are becoming more and more stringent. Open-ended PHC pipe piles, as a type of pile foundation, do not need to make pile heads. They have the characteristics of high bearing capacity, stable quality, fast construction speed, no pollution, low noise, and low engineering cost. They are very suitable for It is used in urban areas and other coastal soft soil areas where noise is restricted. At present, the application of prefabricated piles is increasing day by day, which has far exceeded its theoretical and experimental research, which increases the uncertainty of prefabricated piles in practical engineering applications. The building foundation needs to meet the requirements of deformation and bearing capacity at the same time. The bearing capacity of piles is divided into two parts: pile side friction resistance and pile tip resistance. For friction piles, the ratio of pile tip resistance to the total bearing capacity The resistance is much smaller, but the opposite is true for end-supported piles. In terms of pile end resistance, it is an important part of pile bearing capacity and has been valued by scholars and engineers at home and abroad. Because the pile tip resistance is affected by factors such as the construction method of the pile, the characteristics of the soil layer and the bearing layer, the depth into the bearing layer, and the size of the pile, the interaction between the pile tip soil and the pile becomes very complicated. There are many methods for determining the pile end resistance, but because there are too many uncertainties in the end resistance problem, there is still a lot of work to be done in this field, both in terms of theoretical research, practical accumulation and experimental research. Sometimes, when the foundation has a large settlement, the resistance of the pile end can be fully exerted, but this does not meet the requirements of the building for settlement. Therefore, it is necessary to adopt a new type of on-site test method to quickly and accurately determine the pile end resistance, on the one hand, it can make up for the deficiencies of the existing testing technology. Chinese patent 201310500315.8 discloses a prestressed high-strength concrete pipe pile pile end resistance test device , belongs to the technical field of resistance testing equipment. The test device is composed of three reinforced steel plates, steel casing, axial force meter, stiffener, bolts, shielded wires and vibrating wire frequency reading instrument. The test device can realize the static pressure construction The prestressed pipe pile test pile tip resistance solves the difficulty of determining the pile tip resistance caused by the complex interaction between pile and soil. However, the existing testing device fails to reflect the real construction effect of pipe piles. The soil plugging effect and the pile tip resistance provided by the wall thickness are combined, and the measured pile tip resistance is greater than the actual value; experience and lay the groundwork.

Invention content:

The purpose of the invention of the utility model is to overcome the shortcomings of the prior art, to optimize and improve the test accuracy of pile end resistance under the premise of retaining the construction effect of the original open concrete pipe pile, and to provide a construction method using static pressure method or hammering method. The PHC pipe pile end resistance test device with open end, installs a temperature self-compensating fiber grating soil pressure sensor at the pile end, uses the fiber grating demodulator to measure the change of the center wavelength of the fiber grating, and then calculates the pile end resistance .

In order to achieve the above object, the main structure of the open-ended PHC pipe pile end resistance testing device of the utility model includes a pipe pile, a base steel plate, a temperature self-compensating fiber grating soil pressure sensor, an armored optical cable, and a fiber grating analysis Meter, traction groove, inner wall groove, first borehole of pile body, outer wall groove, second borehole of pile body, flange joint, pile welding seam and sensor embedding hole, the pipe pile is an open-ended PHC pipe Pile; the inner and outer diameters of the base steel plate with a circular structure and a thickness of 3cm are the same as the inner and outer diameters of the pipe pile, and the base steel plate and the circular steel plate at the end of the pipe pile are welded together; two symmetrical arrangements are reserved on the base steel plate The sensor embedding hole, the diameter of the sensor embedding hole is larger than the temperature self-compensating fiber grating earth pressure sensor, and the base steel plate is reserved with a traction groove with a width of 5mm connected to the sensor embedding hole; the temperature self-compensating fiber grating earth pressure sensor is installed The sensor reserved on the base steel plate is embedded in the hole, and the bottom and side of the temperature self-compensating fiber grating soil pressure sensor are tightly pasted with the pipe pile with planting glue to ensure that the temperature self-compensating fiber grating soil pressure sensor protrudes from the base steel plate. The temperature self-compensating fiber grating earth pressure sensor is integrated with the pipe pile and the base steel plate; the lead wire of the temperature self-compensating fiber grating earth pressure sensor is protected by an armored optical cable; the inner and outer walls of the pipe pile are respectively provided with inner wall grooves and The outer wall is grooved, the pile end of the pipe pile is provided with the first borehole of the pile body, and the top of the pile is provided with the second borehole of the pile body. One borehole is introduced into the outer wall groove of the pile, and then the second borehole of the pile body is drawn out from the inside of the pipe pile to connect with the fiber grating analyzer. The traction groove, the inner wall groove, the first borehole of the pile body, the outer wall groove, The armored optical cable in the second borehole of the pile body is encapsulated with structural glue; the base steel plate prevents the temperature self-compensating fiber grating earth pressure sensor from falling off or being damaged during the construction of the pipe pile, ensuring that the temperature self-compensating fiber grating earth pressure sensor is uniform The force and temperature self-compensating fiber grating soil pressure sensor can automatically eliminate the influence of temperature changes on the test results. Therefore, the test device does not need to consider temperature compensation when testing; An armored optical cable with a flange joint is passed through a borehole, and the armored optical cable is connected with an armored optical cable with a flange joint that is also drawn out from the second borehole of the pile body of another pipe pile, and the The two pipe piles are welded and aligned along the periphery of the pipe pile hoop plate to form a pile welding seam.

The utility model realizes the concrete process of pile end resistance test of open-end PHC pipe pile:

(1) Weld the processed base steel plate with the circular end plate at the end of the pipe pile, wherein the base steel plate reserves a sensor embedding hole near the inner edge of the pile end (the diameter is slightly larger than that of the temperature self-compensating fiber grating soil The pressure sensor, the depth is slightly smaller than the thickness of the temperature self-compensating fiber grating earth pressure sensor) and the traction groove with a width of 5mm; the outer wall groove with a width of 5mm is pre-cut along the outer wall of the pile, and an electric drill is used on the pile top and pile end of the pipe pile Drill holes to form the second borehole of the pile body and the first borehole of the pile body, and reserve an inner wall groove with a width of 5 mm on the inner wall of the pile end;

(2) Put the temperature self-compensating fiber grating soil pressure sensor into the sensor embedding hole, and the armored optical cable passes through the pipe pile along the traction groove and the groove on the inner wall, then along the groove of the pile body, and finally from the pile body Lead out from the second borehole and temporarily fix the whole process, and then pour the embedding glue into the inner wall groove, outer wall groove, the second hole of the pile body and the first hole of the pile body. At this time, it is necessary to ensure the temperature self-compensating fiber grating The soil pressure sensor is flush with the soil contact surface at the pile end of the pipe pile to reflect the interaction between the pile end and rock and soil;

(3) After the reinforcement glue is cured for 2 hours, connect the armored optical cable led by the pipe pile to the fiber grating analyzer. On the one hand, check whether the connection of the test device is intact, and on the other hand, check whether the temperature self-compensating fiber grating earth pressure sensor is correct. Damaged; measure the initial value of the temperature self-compensating fiber grating earth pressure sensor installed and positioned in time before using static pressure or hammering construction, and then carry out construction according to the specific requirements of "Technical Specifications for Building Pile Foundations" (JGJ94-2008) , Make construction records and data storage during the construction process, and protect the testing equipment during use;

(4) If the length of a pipe pile does not reach the depth specified in the design, the pile connection shall be carried out. At this time, the armored optical cable shall be packaged along the pile body in advance for the upper section pile, and the first drilled hole shall be drilled from the pile body. Pass through the armored optical cable with flange joints, and connect it with the armored optical cable with flange joints drawn from the second drill hole that has been pressed into the pile body to ensure that the upper and lower flanges are well connected. The upper and lower piles are welded and aligned along the periphery of the pipe pile hoop to ensure the welding quality. After the above work is completed, use static pressure or hammering construction methods to continue penetration until the pile sinking control conditions required by the design are met.

Before the utility model is used, the temperature self-compensating fiber grating earth pressure sensor is calibrated. When in use, the outer normal of the pressure surface of the temperature self-compensating fiber grating earth pressure sensor is collinear with the outer normal of the rock-soil contact surface. Ensure that the stress state of the pipe pile is normally transmitted to the rock and soil layer at the pile end through the temperature self-compensating fiber Bragg grating soil pressure sensor, and measure the initial value in time after the device is installed; during the construction of the pipe pile, use the fiber Bragg grating analyzer to read Data, according to the parameter index of the device, the read data and the formula (1) Δλ _B = K _ε Δε _x , the formula (2) Q _pk = EΔε _x Α _p to calculate the pile tip resistance, where Δλ _B is the change of the central wavelength K _ε is the strain sensitivity coefficient of the sensor; Δε _x is the axial strain variation; Q _pk is the pile tip resistance, the unit is kN; E is the elastic modulus of the pipe pile, the unit is MPa; Α _p is the pile tip of the pipe pile Area, in mm ² .

Compared with the prior art, the utility model has the advantages of simple structure, convenient installation, convenient operation, low cost, not easy to be damaged, high test accuracy, strong operability, real-time monitoring and long-term monitoring, wide application, and can also be applied to Other types of precast piles.

Description of drawings:

Fig. 1 is a schematic diagram of the principle structure of the main structure of the open-end PHC pipe pile end resistance testing device of the utility model.

Fig. 2 is a schematic diagram of the principle of pipe pile connection described in the utility model.

Fig. 3 is a schematic diagram of the structure principle of the pile end of the pipe pile described in the utility model.

Fig. 4 is the test result of one of the test piles described in the embodiment of the present invention.

Fig. 5 is the test result of another test pile described in the embodiment of the present invention.

Detailed ways:

Below by embodiment and in conjunction with accompanying drawing, the utility model is further described.

Example:

The main structure of the open-ended PHC pipe pile end resistance testing device described in this embodiment includes a pipe pile 1, a base steel plate 2, a temperature self-compensating fiber grating soil pressure sensor 3, an armored optical cable 4, and a fiber grating analyzer 5. Traction groove 6, inner wall groove 7, pile body first bore hole 8, outer wall groove 9, pile body second bore hole 10, flange joint 11, pile connection seam 12 and sensor embedding hole 13, pipe pile 1 is an open-ended PHC pipe pile; the inner and outer diameters of the base steel plate 2 with a circular structure and a thickness of 3 cm are the same as the inner and outer diameters of the pipe pile 1, and the base steel plate 2 and the circular steel plate at the end of the pipe pile 1 Welded together; two symmetrically arranged sensor embedding holes 13 are reserved on the base steel plate 2, the diameter of the sensor embedding holes 13 is slightly larger than the temperature self-compensating fiber grating earth pressure sensor 3, and the base steel plate 2 is reserved with sensor embedding holes 13 connected traction groove 6 with a width of 5mm; the temperature self-compensating fiber grating earth pressure sensor 3 is installed in the sensor embedding hole 13 reserved on the base steel plate 2, the bottom surface and the side surface of the temperature self-compensating fiber grating earth pressure sensor 3 Use planting glue to stick tightly to the pipe pile 1 to ensure that the temperature self-compensating fiber grating soil pressure sensor 3 slightly protrudes from the base steel plate 2, so that the temperature self-compensating fiber grating soil pressure sensor 3 is integrated with the pipe pile 1 and the base steel plate 2 Overall; the lead wire of the temperature self-compensating fiber grating earth pressure sensor 3 is protected by an armored optical cable 4; the inner and outer walls of the pipe pile 1 are respectively provided with an inner wall groove 7 and an outer wall groove 9, and the pile end of the pipe pile 1 is provided with a pile The first borehole 8 of the pile body, the pile top has a second borehole 10 of the pile body, and the armored optical cable 4 is introduced from the inner wall groove 7 of the pipe pile 1 through the first borehole 8 of the pile body through the traction groove 6 on the base plate 2 The outer wall groove 9 of the pipe pile 1 is then drawn from the inside of the pipe pile 1 through the second borehole 10 of the pile body to be connected with the fiber grating analyzer 5, the traction groove 6, the inner wall groove 7, the first borehole 8 of the pile body, The outer wall groove 9 and the armored optical cable 4 in the second borehole 10 of the pile body are encapsulated with structural glue; the base steel plate 2 prevents the temperature self-compensating fiber grating earth pressure sensor 3 from falling off or being damaged during the construction of the pipe pile 1, ensuring The temperature self-compensating fiber grating soil pressure sensor 3 is uniformly stressed, and the temperature self-compensating fiber grating soil pressure sensor 3 can automatically eliminate the influence of temperature changes on the test results. Therefore, this test method does not need to consider temperature compensation; a pipe pile When the length of 1 is not enough, pass the armored optical cable 4 with flange joint 11 from the first borehole 8 of the pile body, and connect the armored optical cable 4 with the second borehole 10 of the pile body of another pipe pile 1 The lead-out armored optical cable 4 with the same flange joint 11 is connected, and the two pipe piles are welded and aligned along the periphery of the pipe pile hoop plate to form a pile welding seam 12 .

This embodiment realizes the specific process of pile end resistance test of open-ended PHC pipe pile:

(1) Weld the processed base steel plate 2 and the circular end plate at the pile end of the pipe pile 1 together, wherein the base steel plate 2 reserves a sensor embedding hole 13 (diameter slightly larger than the temperature self-compensating hole 13) near the inner edge of the pile end. type fiber grating earth pressure sensor 3, the depth is slightly smaller than the thickness of temperature self-compensating fiber grating earth pressure sensor 3) and the traction groove 6 of width 5mm; The pile top and the pile end of 1 are drilled with an electric drill to form the second borehole 10 of the pile body and the first borehole 8 of the pile body, and reserve an inner wall groove 7 with a width of 5mm on the pile end inner wall;

(2) Put the temperature self-compensating fiber grating earth pressure sensor 3 into the sensor embedding hole 13, and the armored optical cable 4 passes through the pipe pile along the traction groove 6 and the inner wall groove 7, and then along the pile body groove 9 along the line , and finally lead out from the second borehole 10 of the pile body and temporarily fix the whole process, and then pour the planting glue into the inner wall groove 7, the outer wall groove 9, the second pile body bore hole 10 and the pile body first borehole 8 for encapsulation , at this time, it is necessary to ensure that the temperature self-compensating fiber grating soil pressure sensor 3 is flush with the soil contact surface at the pile tip of the pipe pile to reflect the interaction between the pile tip and rock and soil;

(3) After the reinforcement glue is cured for 2 hours, connect the armored optical cable 4 led out of the pipe pile 1 to the fiber grating analyzer 5. On the one hand, check whether the connection of the test device is intact, and on the other hand, check the soil of the temperature self-compensating fiber grating Whether the pressure sensor 3 is damaged; measure the initial value of the temperature self-compensating fiber grating earth pressure sensor 3 installed and positioned in time before using static pressure or hammering construction, and then according to the "Technical Specifications for Building Pile Foundations" (JGJ94-2008) Carry out construction according to the specific requirements, make construction records and data storage during the construction process, and protect the testing equipment during use;

(4) If the length of a pipe pile does not reach the depth specified in the design, the pile connection shall be carried out. At this time, the armored optical cable shall be packaged along the pile body in advance for the upper section pile, and 8 holes shall be drilled from the first pile body. Pass the armored optical cable 4 with the flange joint 11 in the middle, and connect it with the armored optical cable 4 that also has the flange joint 11 that is drawn out from the second borehole 10 of the pile body that has been pressed into the pile body, to ensure that the up and down method The blue connection is good, and the upper and lower piles are welded and aligned along the periphery of the pipe pile hoop to ensure the welding quality. After the above work is completed, use static pressure or hammering construction methods to continue penetration until the pile sinking control conditions required by the design are met.

The test pile of this embodiment is the PHC-AB400 type end open type prestressed concrete pipe pile, the wall thickness is 95mm, and the pile length is 23m. Two test piles are used to test respectively under the test site as shown in Table 1. The test results They are shown in Figure 4 and Figure 5 respectively.

Table 1: Geological conditions of the test site

Claims (1)

1. a kind of end open type PHC pile pile end resistance test devices, it is characterised in that agent structure includes pile pile, base steel Plate, temperature self-compensation type fiber grating earth pressure sensor, armored optical cable, fiber grating analyzer, traction grooved, inboard wall groove, Pile body first drills, unit with grooves in outer wall, pile body second drills, bump joint, pile extension weld seam and sensor embedded hole, pile pile are end Open type PHC pile piles；Cirque structure, the base steel plate inner and outer diameter that thickness is 3cm are identical with pile pile inner and outer diameter, base steel Plate welds together with the circular ring shape steel plate carried at pipe pile end；It is embedding that two sensors being arranged symmetrically are reserved on base steel plate Enter hole, the diameter of sensor embedded hole is more than temperature self-compensation type fiber grating earth pressure sensor, is reserved with base steel plate It is connected with sensor embedded hole, the traction grooved that width is 5mm；Temperature self-compensation type fiber grating earth pressure sensor is installed on bottom In the sensor embedded hole reserved on seat steel plate, the bottom surface of temperature self-compensation type fiber grating earth pressure sensor and side are planted Muscle glue is closely pasted with pile pile, temperature self-compensation type fiber grating earth pressure sensor protrusion base steel plate, temperature self-compensation type Fiber grating earth pressure sensor is integral structure with pile pile, base steel plate；Temperature self-compensation type optical fiber grating soil pressure passes The lead of sensor is protected with armored optical cable；Inboard wall groove and unit with grooves in outer wall, the stake end of pile pile are had on the inside and outside wall of pile pile It is provided with pile body first to drill, stake top is provided with pile body second and drills, and armored optical cable is by the traction grooved on base steel plate from pile pile Inboard wall groove drills through pile body first introduces the unit with grooves in outer wall of pile pile, then through pile body second drill from the inside of pile pile draw with Fiber grating analyzer connects, and traction grooved, inboard wall groove, pile body first drills, the armouring in the drilling of unit with grooves in outer wall, pile body second Optical cable is encapsulated using structure glue；When the length of a root canal pile is inadequate, it is pierced by from the drilling of pile body first with bump joint Armored optical cable, the armouring light again with bump joint drawn during the pile body second of armored optical cable and another root canal pile is drilled Cable connects, and two root canal piles are formed pile extension weld seam along the welding alignment of tubular pile hoop plate periphery.