Rigid composite pile bearing capacity testing device and method

Abstract

The present application discloses a bearing capacity test device for a rigid composite pile, and relates to the technical field of composite piles, including a composite pile body and a pressure device, the composite pile body is installed with a fixed frame that cooperates with it, a sensor monitoring device for monitoring the performance of the composite pile body is installed on the fixed frame, and the composite pile body includes an inner core and an outer core arranged coaxially; a pad is arranged above the composite pile body; the pressure device includes a pressure frame and a pressurization system, the fixed frame is located inside the pressure frame, and the diameter of the simulated soil layer is equal to 2.5-3.5 times the diameter of the outer core; the sensor monitoring device includes a distributed optical fiber sensor and a displacement meter, the distributed optical fiber sensor is arranged on the fixed frame, and a load box is arranged at the bottom of the inner core; the monitoring device is connected to the solar cell system and the wireless demodulator in sequence through a signal line, the wireless demodulator is connected to the cloud processor communication, and the cloud processor is connected to the client. The present application can qualitatively analyze the influence of environmental factors on different structural materials, and multiple parameters and environmental conditions in the pile body are automatically monitored in real time and the bearing capacity is tested, and the test results can be viewed at any time through the client.

Description

Technical Field

[0001] The invention relates to the technical field of composite piles, and in particular to a bearing capacity testing device and method for rigid composite piles. Background Art

[0002] Composite pile foundation refers to a pile foundation that takes into account the bearing capacity of the soil between piles under the pedestal. The difference in design between composite pile foundation and ordinary pile foundation is that in addition to considering the bearing capacity of the pile body itself, the composite pile foundation also needs to consider the bearing capacity of the soil between piles under the pedestal. The superposition of the two forms the overall bearing capacity of the composite pile foundation, thereby strengthening the bearing capacity of the entire pile foundation. And the rigid composite pile is a new type of composite pile in which the core pile is inserted into the cement soil mixing pile before the initial setting to form a common force. Therefore, pile side friction resistance is bound to occur between the inner core and the outer core, and between the outer core and the soil around the pile. The pile side friction resistance is mainly measured by the characteristic value of the side resistance. The ultimate load that a unit pile can withstand is the maximum static load test pressure divided by the safety factor of 2.0, which is the standard value obtained. In order to solve the problem of monitoring the bearing capacity of rigid composite piles and the influence of humidity and temperature, the present application proposes a rigid composite pile bearing capacity test device. Summary of the invention

[0003] The present invention aims at solving one or more of the above existing problems and proposes a bearing capacity testing device for a rigid composite pile.

[0004] According to the first aspect of the present application, a bearing capacity test device for a rigid composite pile comprises a composite pile body and a pressure device, the composite pile body is installed with a fixing frame that cooperates with the composite pile body, a sensor monitoring device for monitoring the performance of the composite pile body is installed on the fixing frame, the composite pile body comprises an inner core and an outer core that are coaxially arranged; a pad is arranged above the composite pile body;

[0005] The pressure device includes a pressure frame and a pressure system. The fixed frame is located inside the pressure frame. The diameter of the simulated soil layer is equal to 2.5-3.5 times the diameter of the outer core.

[0006] The fixed frame includes two horizontal frames, which are connected by vertical steel pipes. Each horizontal frame includes an inner ring and an outer ring, which are concentrically arranged. The inner ring and the outer ring are connected by a set of horizontal pipes, and the inner core is arranged in the inner ring.

[0007] The sensor monitoring device includes a distributed optical fiber sensor and a displacement meter. The distributed optical fiber sensor is arranged on a fixed frame, and a load box is arranged at the bottom of the inner core;

[0008] There are two groups of displacement meters, each group has two displacement meters. The first group is installed on a square rigid steel sheet close to the pad, and the two displacement meters are symmetrically distributed about the center point of the pad; the second group is installed on a square rigid steel sheet close to the outer core, and the two displacement meters are symmetrically distributed about the center point of the outer core;

[0009] The monitoring device is connected to the solar cell system and the wireless demodulator in sequence through signal lines, the wireless demodulator is connected to the cloud processor for communication, and the cloud processor is connected to the client.

[0010] As a feasible way, the type of simulated soil layer is selected as layered soft soil, and the standard penetration test number N value of the simulated soil layer does not exceed 80; the material of the pad is cast iron, the Rockwell hardness is 40-50HRC, the diameter of the pad is not greater than the diameter of the high-strength inner core, and the height of the pad is 5-10cm.

[0011] As a feasible way, an inner core fixing frame is manufactured according to the length of the inner core, the inner core frame is located in the fixing frame, and the inner core frame enables the inner core to dock with the load box.

[0012] The present application also provides a method for testing the bearing capacity of a rigid composite pile, using the above-mentioned rigid composite pile bearing capacity testing device, the method is as follows:

[0013] Step 1: Make an inner core fixing frame according to the length of the inner core, connect the inner core fixing frame with the load box, pass the inner core fixing frame upward from the bottom of the inner core, so that the inner core and the load box are connected, and use the inner core fixing frame to lead the displacement pipeline of the load box to the top of the composite pile;

[0014] Step 2: Make a fixing frame, open an outer ring groove on the outer ring of the fixing frame for placing the sensor, and then weld the fixing frame to the inner core;

[0015] Step 3: After the outer core is stirred, the inner core connected to the fixing frame is lifted and piled. After the pile is sunk to the designated position, the survival rate of the sensor is checked;

[0016] Step 4: Select a suitable press machine, set the speed of the press machine to 0.01mm / min-100mm / min, the pressurizing system is a CNC hydraulic drive device, the moving stroke is not less than 10cm, and the maximum load applied is not less than 1200kN;

[0017] Step 5: Place a pad on top of the rigid composite pile so that the center of the pad coincides with the center axis of the rigid composite pile;

[0018] Step 6: Install 4 displacement meters and make them all in the same vertical plane;

[0019] Step 7: Start the press machine, and the control process is as follows: before the pressurizing system contacts the rigid composite pile, the moving speed of the pressurizing system is 22 mm / min, when the distance between the pressurizing system and the rigid composite pile is 0.8 cm, the moving speed of the pressurizing system is reduced to 4 mm / min, and when the pressurizing system contacts the rigid composite pile, the moving speed of the pressurizing system is reduced to 1 mm / min;

[0020] Step 8: When the vertical stress applied by the pressurizing system is 0.5 MPa, the vertical pressure is kept unchanged and formal pressurization begins at a speed of 0.05 / min. The pressure of the loading system, i.e., the lateral friction between the inner core and the outer core, is recorded through the cloud processor;

[0021] Step 9: When the inner core and the outer core are relatively displaced and the distance of dislocation is greater than 3 cm, stop pressurizing and unload the pressurizing system. After the pressurizing system is separated from the rigid composite pile, take out the sample and sort out the test data to obtain a curve of the side resistance changing with displacement. Monitor the temperature and humidity inside the pile through a monitoring device, upload the data to the cloud, and analyze the impact of different temperatures and humidity on the bearing quality of the pile body in combination with the curve of the pile inner resistance changing with displacement.

[0022] The beneficial effects of the present invention are:

[0023] The present invention provides a method for qualitatively analyzing the influence of environmental factors on different structural materials, automatically monitoring various parameters and environmental conditions in the pile body in real time and testing the bearing capacity, and the test results can be viewed through the client at any time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the fixed frame in the bearing capacity test device of the rigid composite pile;

[0025] Figure 2 It is a structural schematic diagram of a bearing capacity test device for rigid composite piles;

[0026] The above drawings show clear embodiments of the present disclosure, which will be described in more detail below. These drawings and text descriptions are not intended to limit the scope of the present disclosure in any way, but to illustrate the concepts of the present disclosure to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. In the absence of conflict, the following embodiments and the features in the embodiments may be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0029] like Figure 1-2 As shown, a bearing capacity test device for a rigid composite pile comprises a composite pile body and a pressure device. The composite pile body is installed with a fixing frame 1 which cooperates with the fixing frame. A sensor monitoring device for monitoring the performance of the composite pile body is installed on the fixing frame. The composite pile body comprises an inner core 2 and an outer core 3 which are coaxially arranged. A pad is arranged above the composite pile body. The pressure device comprises a pressure frame and a pressurizing system 5. The fixing frame is located inside the pressure frame. The diameter of the simulated soil layer 6 is equal to 2.5-3.5 times the diameter of the outer core. The fixing frame includes two horizontal frames 7. The two horizontal frames are connected by a vertical steel pipe 8. Each horizontal frame comprises an inner ring 71 and an outer ring 72. The inner ring and the outer ring are concentrically arranged. , the inner ring and the outer ring are connected by a set of horizontal tubes, and the inner core is arranged in the inner ring; the sensor monitoring device includes a distributed optical fiber sensor 9 and a displacement meter 10, the distributed optical fiber sensor 9 is arranged on a fixed frame 1, and a load box is arranged at the bottom of the inner core; the displacement meter 10 is in two groups, each group has two, the first group is installed on a square rigid steel sheet close to the pad, and the two displacement meters are symmetrically distributed about the center point of the pad; the second group is installed on a square rigid steel sheet close to the outer core, and the two displacement meters 7 are symmetrically distributed about the center point of the outer core; the inner ring and the outer ring in this application are both medium carbon quenched and tempered steel rings, the inner ring diameter is the same as the inner core outer diameter, and the outer ring diameter is the same as the outer core inner diameter. The inner core fixing frame is made according to the length of the inner core, and the inner core frame is located in the fixing frame, and the inner core frame enables the inner core to dock with the load box.

[0030] It should be noted that the distributed optical fiber sensor includes a distributed optical fiber Bragg grating stress sensor and an integrated optical fiber Bragg grating temperature and humidity sensor. The integrated optical fiber Bragg grating temperature and humidity sensor is arranged in the outer ring groove, and the distributed optical fiber Bragg grating stress sensor is arranged on the groove of the vertical steel pipe. During installation, the packaged optical fiber sensor can be laid along the groove, initially fixed with AB glue, and then tied with a plastic tie for secondary fixing;

[0031] The monitoring device is connected to the solar cell system and the wireless demodulator in turn through a signal line, the wireless demodulator is connected to the cloud processor for communication, and the cloud processor is connected to the client to save and view the processed data. The displacement meter is connected to the data storage system through a data line, and the displacement meter and the press are connected to the solar cell system and the wireless demodulator in turn through a signal line.

[0032] The type of simulated soil layer is layered soft soil, and the standard penetration test blow number N value of the simulated soil layer does not exceed 80; the material of the pad is cast iron, the Rockwell hardness is 40-50HRC, the diameter of the pad is not greater than the diameter of the high-strength inner core, and the height of the pad is 5-10cm.

[0033] The present application also provides a method for testing the bearing capacity of a rigid composite pile, using the above-mentioned rigid composite pile bearing capacity testing device, the method is as follows:

[0034] Step 1: Make an inner core fixing frame according to the length of the inner core, connect the inner core fixing frame with the load box, pass the inner core fixing frame upward from the bottom of the inner core, so that the inner core and the load box are connected, and use the inner core fixing frame to lead the displacement pipeline of the load box to the top of the composite pile;

[0035] Step 2: Make a fixing frame, open an outer ring groove on the outer ring of the fixing frame for placing the sensor, and then weld the fixing frame to the inner core;

[0036] Step 3: After the outer core is stirred, the inner core connected to the fixing frame is lifted and piled. After the pile is sunk to the designated position, the survival rate of the sensor is checked;

[0037] Step 4: Select a suitable press machine, set the speed of the press machine to 0.01mm / min-100mm / min, the pressurizing system is a CNC hydraulic drive device, the moving stroke is not less than 10cm, and the maximum load applied is not less than 1200kN;

[0038] Step 5: Place a pad on top of the rigid composite pile so that the center of the pad coincides with the center axis of the rigid composite pile;

[0039] Step 6: Install 4 displacement meters and make them all in the same vertical plane;

[0040] Step 7: Start the press machine, and the control process is as follows: before the pressurizing system contacts the rigid composite pile, the moving speed of the pressurizing system is 22 mm / min, when the distance between the pressurizing system and the rigid composite pile is 0.8 cm, the moving speed of the pressurizing system is reduced to 4 mm / min, and when the pressurizing system contacts the rigid composite pile, the moving speed of the pressurizing system is reduced to 1 mm / min;

[0041] Step 8: When the vertical stress applied by the pressurizing system is 0.5 MPa, the vertical pressure is kept unchanged and formal pressurization begins at a speed of 0.05 / min. The pressure of the loading system, i.e., the lateral friction between the inner core and the outer core, is recorded through the cloud processor;

[0042] Step 9: When the inner core and the outer core are relatively displaced and the distance of dislocation is greater than 3 cm, stop pressurizing and unload the pressurizing system. After the pressurizing system is separated from the rigid composite pile, take out the sample and sort out the test data to obtain a curve of the side resistance changing with displacement. Monitor the temperature and humidity inside the pile through a monitoring device, upload the data to the cloud, and analyze the impact of different temperatures and humidity on the bearing quality of the pile body in combination with the curve of the pile inner resistance changing with displacement.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0044] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A bearing capacity test device for rigid composite piles, characterized in that: The composite pile body comprises a composite pile body and a pressure device, wherein the composite pile body is installed with a fixing frame (1) which cooperates with the composite pile body, and a sensor monitoring device for monitoring the performance of the composite pile body is installed on the fixing frame (1). The composite pile body comprises an inner core (2) and an outer core (3) which are coaxially arranged; a pad (4) is arranged above the composite pile body; The pressure device comprises a pressure frame and a pressure system (5), the fixed frame (1) is located inside the pressure frame, and the diameter of the simulated soil layer (6) is equal to 2.5-3.5 times the diameter of the outer core; The fixed frame includes two horizontal frames (7), the two horizontal frames are connected by a vertical steel pipe (8), each horizontal frame includes an inner ring (71) and an outer ring (72), the inner ring (71) and the outer ring (72) are concentrically arranged, the inner ring (71) and the outer ring (72) are connected by a group of horizontal pipes, and the inner core (2) is arranged in the inner ring (71); The sensor monitoring device comprises a distributed optical fiber sensor (9) and a displacement meter (10), wherein the distributed optical fiber sensor (8) is arranged on a fixed frame, and a load box is arranged at the bottom of the inner core (2); The displacement meters (10) are in two groups, each group having two displacement meters. The first group is mounted on a square rigid steel sheet close to the backing plate (4), and the two displacement meters are symmetrically distributed about the center point of the backing plate; the second group is mounted on a square rigid steel sheet close to the outer core, and the two displacement meters are symmetrically distributed about the center point of the outer core; The monitoring device is connected to the solar cell system and the wireless demodulator in sequence through signal lines, the wireless demodulator is connected to the cloud processor for communication, and the cloud processor is connected to the client.

2. The bearing capacity testing device for reinforced composite piles according to claim 1, characterized in that: The type of the simulated soil layer (6) is layered soft soil, and the standard penetration test number N value of the simulated soil layer does not exceed 80; the material of the pad is cast iron, the Rockwell hardness is 40-50HRC, the diameter of the pad is not greater than the diameter of the high-strength inner core, and the height of the pad is 5-10cm.

3. The bearing capacity testing device for reinforced composite piles according to claim 2, characterized in that: An inner core fixing frame is made according to the length of the inner core (2), the inner core frame is located inside the fixing frame, and the inner core frame enables the inner core to dock with the load box.

4. A method for testing the bearing capacity of a rigid composite pile, characterized in that: The bearing capacity test method of the rigid composite pile described in claims 1-3 is adopted, and the method is as follows: Step 1: Make an inner core fixing frame according to the length of the inner core, connect the inner core fixing frame with the load box, pass the inner core fixing frame upward from the bottom of the inner core, so that the inner core and the load box are connected, and use the inner core fixing frame to lead the displacement pipeline of the load box to the top of the composite pile; Step 2: Make a fixing frame, open an outer ring groove on the outer ring of the fixing frame for placing the sensor, and then weld the fixing frame to the inner core; Step 3: After the outer core is stirred, the inner core connected to the fixing frame is lifted and piled. After the pile is sunk to the designated position, the survival rate of the sensor is checked; Step 4: Select a suitable press machine, set the speed of the press machine to 0.01mm / min-100mm / min, the pressurizing system is a CNC hydraulic drive device, the moving stroke is not less than 10cm, and the maximum load applied is not less than 1200kN; Step 5: Place a pad on top of the rigid composite pile so that the center of the pad coincides with the center axis of the rigid composite pile; Step 6: Install 4 displacement meters and make them all in the same vertical plane; Step 7: Start the press machine, and the control process is as follows: before the pressurizing system contacts the rigid composite pile, the moving speed of the pressurizing system is 22 mm / min, when the distance between the pressurizing system and the rigid composite pile is 0.8 cm, the moving speed of the pressurizing system is reduced to 4 mm / min, and when the pressurizing system contacts the rigid composite pile, the moving speed of the pressurizing system is reduced to 1 mm / min; Step 8: When the vertical stress applied by the pressurizing system is 0.5 MPa, the vertical pressure is kept unchanged and formal pressurization begins at a speed of 0.05 / min. The pressure of the loading system, i.e., the lateral friction between the inner core and the outer core, is recorded through the cloud processor; Step 9: When the inner core and the outer core are relatively displaced and the distance of dislocation is greater than 3 cm, stop pressurizing and unload the pressurizing system. After the pressurizing system is separated from the rigid composite pile, take out the sample and sort out the test data to obtain a curve of the side resistance changing with displacement. Monitor the temperature and humidity inside the pile through a monitoring device, upload the data to the cloud, and analyze the impact of different temperatures and humidity on the bearing quality of the pile body in combination with the curve of the pile inner resistance changing with displacement.

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