Anchor pile reaction system and test method for synchronous static load test of compression and tension bearing capacity

Abstract

The present application relates to a synchronous static load test anchor pile reaction system and test method for compressive and tensile bearing capacity, which includes a support frame, a compression pile group, a tensile pile group, a pressure applying component, a first force monitor for monitoring the force value of the pressure applying component, a tensile force applying component, and a second force monitor for monitoring the force value of the tensile force applying component, the compression pile group is projected onto a horizontal plane to form a first projection figure, the tensile pile group is projected onto a horizontal plane to form a second projection figure, and the center of the first projection figure and the second projection figure is within the other; the pressure applying component is vertically arranged between the support frame and the compression pile group, and the pressure applying component is used to drive the support frame and the compression pile group away from each other; the tensile force applying component is vertically arranged between the support frame and the tensile pile group, and the tensile force applying component is used to drive the support frame and the tensile pile group closer to each other. The present application can realize the synchronous static load test of multiple piles, which can shorten the construction period and reduce the construction cost.

Description

Technical Field

[0001] The present application relates to the technical field of static load test and detection of engineering pile foundations, and in particular to a static load test anchor pile reaction system and test method for compressive and tensile bearing capacity. Background Art

[0002] Pile foundation testing is an important part of ensuring project quality and safety, and the pile foundation static load test is the test method that is closest to the actual working state of the pile when it is subjected to axial load. It is the most direct and reliable test method to determine the axial bearing capacity of a single pile and its settlement characteristics.

[0003] In the related art, the method of static load test on pile foundation usually adopts the anti-anchor method, which is mainly to set a reaction force support frame near the pile foundation to be tested, and then set a force-applying device on the reaction force support frame. If it is necessary to test the pull-out performance parameters of the pile foundation, the force-applying device is used to apply an upward pull-out force to the pile foundation; if it is necessary to test the compressive performance parameters of the pile foundation, the force-applying device is used to apply a downward pressure to the pile foundation.

[0004] In the test design of the bearing capacity of pile foundations in some strata, there is a need to obtain both the pull-out performance parameters and the compressive performance parameters of the pile foundation in the stratum. If the commonly used static load test method mentioned above is adopted, it is usually necessary to set up at least two sets of reaction support frames and force-applying devices for testing, which increases the test cost to a certain extent. Summary of the invention

[0005] On the one hand, in order to reduce the test cost of simultaneously obtaining the pull-out and compressive performance parameters of the pile body in the stratum, the present application provides an anchor pile reaction force system for synchronous static load testing of compressive and pull-out bearing capacity.

[0006] The present application provides a compressive and tensile bearing capacity synchronous static load test anchor pile reaction system adopts the following technical solution:

[0007] A compressive and tensile bearing capacity synchronous static load test anchor pile reaction system, comprising:

[0008] Support frame;

[0009] A compression pile group is vertically connected to the soil, and the compression pile group is projected onto a horizontal plane to form a first projection figure;

[0010] An anti-pullout pile group is vertically connected to the soil, and the anti-pullout pile group is projected onto a horizontal plane to form a second projection figure, wherein the center of one of the first projection figure and the second projection figure is located within the other;

[0011] A pressure applying assembly is vertically arranged between the support frame and the compression pile group, and is used to drive the support frame and the compression pile group to move away from each other;

[0012] A first force monitor, used to monitor the force value of the pressure applying component;

[0013] A pull-out force applying assembly is vertically arranged between the support frame and the pull-out pile group, and is used to drive the support frame and the pull-out pile group to approach each other;

[0014] The second force monitor is used to monitor the force value of the pulling force applying component.

[0015] By adopting the above technical solution, after selecting the test area, a compression pile group and an anti-pulling pile group are set in the soil; then, a support frame is installed in the test area, and the setting of the support frame can be used for the installation of the pressure applying component and the pull-out force applying component. During the test after the installation is completed, the pressure applying component applies pressure to the compression pile group, and uses the first force monitor to monitor the force value of the pressure applying component; while the pull-out force applying component applies pull-out force to the pull-out pile group, and uses the second force monitor to monitor the force value of the pull-out force applying component. At this time, the purpose of performing compression tests on compression piles and anti-pulling tests on pull-out piles can be achieved by setting only one set of support frames, reducing the setting of support frames and having the effect of reducing costs to a certain extent. At the same time, when the pressure applying component applies pressure to the pile body of the compression pile group, it will also generate an upward lifting force on the support frame; when the pull-out force applying component applies pressure to the pile body of the pull-out pile group, it will generate a downward pressure on the support frame. If two sets of support frames are used to carry out compression and pull-out tests respectively, it is usually necessary to set up reaction force devices for balancing the compression test and for balancing the pull-out test separately; in the present scheme, the same support frame is used as the load-bearing frame for the compression test and the pull-out test, and the lifting force and the resistance force exerted on the support frame can be kept balanced by monitoring and controlling the applied force value; that is, the resistance force exerted on the support frame due to the pull-out test can be used as the balancing reaction force of the compression test, and the lifting force exerted on the support frame due to the compression test can be used as the balancing reaction force of the pull-out test, so that the entire reaction force system is simpler and more convenient to install and use.

[0016] Optionally, the center of the first projection figure is vertically aligned with the center of the second projection figure.

[0017] By adopting the above technical solution, the lifting force and the resisting force on the support frame in the static load test can be more balanced, so as to reduce the situation where the support frame is tilted due to excessive force on one side and affects the test accuracy.

[0018] Optionally, the compression pile group includes one compression pile, the pull-out pile group includes two pull-out piles, the compression pile and the pull-out piles are arranged along a straight line, and the compression pile is located at the midpoint of the line connecting the two pull-out piles.

[0019] By adopting the above technical solution, in the actual test process, when the compression pile and the pull-out pile are vertically displaced by the same distance, the pressure value that the compression pile can withstand is usually greater than the pull-out value that the pull-out group can withstand, so the maximum load preset for the compression pile in the compression test is usually greater than the maximum load preset for the pull-out pile in the pull-out test. By setting the compression pile between the two pull-out piles, in the synchronous static load test, the pressure on the compression pile can be twice the pull-out force on the pull-out pile; in the process of the step-by-step loading test, the maximum loads of the compression test and the pull-out test can be reached more quickly, improving the overall test efficiency.

[0020] Optionally, the compression pile group includes one compression pile, the pull-out pile group includes four pull-out piles, the four pull-out piles are arranged in a rectangular shape, and the compression pile is located at the center of the rectangle formed by the four pull-out piles.

[0021] By adopting the above technical solution, the support frame is subjected to four resisting forces due to the pull-out test, and the force application points of the four resisting forces on the support frame are arranged in a rectangular shape to form a force application surface; compared with the situation where there are only two resisting force application points, it is easier to maintain the force balance of the support frame and reduce the possibility of the support frame tilting.

[0022] Optionally, the distance d between the compression pile and the pull-out pile is not less than three times the maximum pile diameter of the compression pile and the pull-out pile, and the distance d is ≥ 2m.

[0023] By adopting the above technical scheme, when the compression piles and the pull-out piles undergo vertical displacement due to force, the soil layer is easily disturbed. By pre-controlling the distance between the compression piles and the pull-out piles, the influence of the soil layer disturbance on the compression test and the pull-out test can be reduced, thereby improving the accuracy of the compression test and the pull-out test.

[0024] Optionally, the pressure applying assembly includes a plurality of first lifting members, each of which is connected to a control module for controlling the first lifting members to perform lifting, and the plurality of first lifting members are projected on a horizontal plane to form a third projection figure, wherein the center of the third projection figure is vertically aligned with the center of the first projection figure.

[0025] By adopting the above technical solution, the centers of the first projection figure, the second projection figure and the third projection figure are vertically aligned, which makes the force points of the support frame more balanced and can reduce the occurrence of the support frame being tilted due to force.

[0026] Optionally, the pull force applying assembly includes an upper anchor, a lower anchor, a second lifting member and a tension rod, the upper anchor is vertically slidably connected to the support frame, and the lower anchor is connected to the pile body in the pull-out pile group; the second lifting member is arranged between the upper anchor and the support frame, and the second lifting member is used to drive the upper anchor and the support frame away from each other, the tension rod is vertically arranged, and the upper end of the tension rod is connected to the upper anchor, and the lower end is connected to the lower anchor.

[0027] By adopting the above technical solution, the second lifting member is used to drive the upper anchor to move upward relative to the support frame, and the tension rod and the lower anchor are used to transmit the force to the pile body of the pull-out pile group, thereby achieving the purpose of performing a pull-out test on the pull-out pile group; the overall structure is simple and easy to implement.

[0028] Optionally, the pile body in the pull-out pile group is provided with vertical connecting ribs, and the lower anchor is fixedly connected to the connecting ribs.

[0029] By adopting the above technical solution, the pile body in the pull-out pile group is usually cast by concrete, and exposed connecting bars are reserved when the pile body is cast, which can facilitate the fixed connection between the lower anchor and the pile body.

[0030] In a second aspect, the present application provides a method for synchronous static load testing of compressive and tensile bearing capacity.

[0031] The present application provides a method for synchronous static load test of compressive and tensile bearing capacity, which adopts the following technical scheme:

[0032] A method for synchronous static load test of compressive and tensile bearing capacity, using the above-mentioned synchronous static load test anchor pile reaction system, comprises the following steps:

[0033] S1. Preliminary preparation: selecting a test area, planning the layout of compression piles and pull-out piles in the static load test, and determining the setting points of each compression pile and pull-out pile in the test area based on the layout plan; wherein the layout plan includes the number, spacing and arrangement of compression piles and pull-out piles;

[0034] S2, equipment installation, based on the layout plan, compression piles and pull-out piles are correspondingly set at the setting points, a support frame is set up in the test area, a pressure applying component and a first force monitor are installed between the support frame and the compression piles, and a pull-out force applying component and a second force monitor are installed between the support frame and the pull-out piles; wherein the support frame includes a crossbeam, the pressure applying component and the pull-out force applying component both apply force vertically, and the pressure applying component applies an upward lifting force to the crossbeam when applying force to the compression piles, and the pull-out force applying component applies a downward resisting force to the crossbeam when applying force to the pull-out piles;

[0035] S3, load loading, using the pressure applying assembly to apply a pressure load to the compression pile, and using the pull-out applying assembly to apply a pull-out load to the pull-out pile, the pressure load and the pull-out load are both loaded step by step in equal amounts, and a total of 15 levels of loading, the graded load is 1 / 15 of 1-1.5 times the estimated limit load, and each level of loading is maintained for 1-1.5 hours. During the load maintenance process, the vertical displacements of the compression pile and the pull-out pile are measured and recorded;

[0036] S4. Load unloading: gradually unload the load on the compression piles and the pull-out piles. After unloading to zero, remove the equipment.

[0037] By adopting the above technical scheme, the resistance force exerted on the beam due to the pull-out test can be used as a partial balancing reaction force of the compression test, and the lifting force exerted on the beam due to the compression test can be used as a partial balancing reaction force of the pull-out test, thereby reducing the number of structures used to balance the force on the beam, thereby making the entire test method more convenient; at the same time, by using the same beam as the load-bearing member for the compression test and the pull-out test, the stability of the beam can be maintained by monitoring and controlling the force value.

[0038] Optionally, during the load loading and load maintenance process of step S3, the compressive load M and the pull-out load N satisfy the relationship: when M0≤N0, |a Mb N|≤M0 / 15; when M0>N0, |a Mb N|≤N0 / 15; wherein a represents the number of compression piles, b represents the number of pull-out piles, M0 represents the estimated ultimate load of the compression piles, and N0 represents the estimated ultimate load of the pull-out piles.

[0039] By adopting the above technical scheme, a M can reflect the lifting force exerted on the beam due to the compression test, b N can reflect the resistance force exerted on the beam due to the pull-out test, and M0 / 15 will be smaller than the single-stage load of a single compression pile in the static load test, and N0 / 15 will be smaller than the single-stage load of a single pull-out pile in the static load test; the difference between the lifting force and the resistance force exerted on the beam is made smaller than the minimum value of the single-stage compression load and the single-stage pull-out load, and the corresponding difference can be balanced by the connection relationship between the support frame and the ground, so that the beam and the entire support frame can be in a balanced and stable state.

[0040] In summary, the present application includes at least one of the following beneficial technical effects:

[0041] 1. The lifting force of the support frame due to the compression test is used as the balancing reaction force of the pull-out test, making the entire reaction force system simpler, and only one support frame needs to be erected as the load-bearing frame, reducing the test cost;

[0042] 2. The force of the pressure applying component and the pulling force applying component can be adjusted to maintain the force balance of the support frame, improve the stability of the support frame during the entire static load test, and reduce the situation where the support frame tilts and affects the test accuracy;

[0043] 3. It can realize synchronous static load test of multiple piles, which can shorten the construction period and reduce the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a front view of an embodiment of the present application.

[0045] Figure 2 It is a top view of an embodiment of the present application.

[0046] Figure 3 It is a side view of an embodiment of the present application.

[0047] Explanation of the reference numerals in the accompanying drawings: 1. support frame; 11. pier; 12. crossbeam; 2. compression pile; 3. pull-out pile; 31. connecting rib; 4. first jacking member; 41. pressure plate; 5. pull-out force applying assembly; 51. upper anchor; 52. lower anchor; 53. second jacking member; 531. pad; 54. tension rod; 541. casing; 6. reference pile; 61. reference beam. DETAILED DESCRIPTION

[0048] The following is combined with Figure 1-3 This application is described in further detail.

[0049] The present application discloses a compressive and tensile bearing capacity synchronous static load test anchor pile reaction system. Figure 1 and Figure 2 The anchor pile reaction system for the synchronous static load test of compressive and tensile bearing capacity includes a support frame 1 erected on the ground, a compression pile group vertically connected to the soil, a tensile pile group vertically connected to the soil, a pressure applying component and a tensile force applying component 5. Among them, the support frame 1 is fixedly erected on the ground, the pressure applying component is installed between the support frame 1 and the compression pile group, and is used to apply downward pressure to the pile body in the compression pile group; the tensile force applying component 5 is installed between the support frame 1 and the tensile pile group, and is used to apply upward tensile force to the pile body in the tensile pile group.

[0050] During the simultaneous static load tests of compression and pull-out, the resistance force exerted on the support frame 1 by the pull-out test can be used as the balancing reaction force of the compression test, or the lifting force exerted on the support frame 1 by the compression test can be used as the balancing reaction force of the pull-out test, making the entire reaction force system simpler.

[0051] Specifically, the support frame 1 includes a vertically arranged pier 11 and a horizontally arranged beam 12; wherein, there are multiple piers 11, and the beam 12 is erected on the pier 11, so as to realize the stable erection of the beam 12 through the pier 11. Meanwhile, in the present embodiment, the beam 12 is composed of four parallel arranged concrete beams. In another embodiment, the beam 12 may also be a single concrete beam or steel beam whose bearing performance meets the test requirements; the specific bearing performance may be 1.5 times or even more than 2 times the maximum load required for the test for reference.

[0052] The compression pile group includes at least one compression pile 2, which is cast with concrete. In order to facilitate the application of pressure to the compression pile 2 during the test, the upper end surface of the compression pile 2 can be exposed to the ground or flush with the ground during the casting of the compression pile 2. The pull-out pile group includes at least two pull-out piles 3, which are also cast with concrete. In order to facilitate the application of pull-out force to the pull-out pile 3 during the test, exposed connecting bars 31 can be reserved during the casting of the pull-out pile 3. In addition, in order to reduce the disturbance of the soil layer during the static load test and interfere with the test, the distance d between the compression column and the pull-out pile 3 needs to be set to not less than three times the diameter of the largest pile body of the compression pile 2 and the pull-out pile 3, and the distance d ≥ 2m.

[0053] At the same time, the compression pile group can be projected onto the horizontal plane to form a first projection figure, and the pull-out pile group can be projected onto the horizontal plane to form a second projection figure. In order to maintain the balance and stability of the support frame 1 during the static load test, the center of the first projection figure can be vertically aligned with the center of the second projection figure.

[0054] Reference Figure 1 and Figure 2 In one embodiment, one compression pile 2 is provided for the compression test, and two pull-out piles 3 are provided for the pull-out test; and the center of the compression pile 2 is located at the midpoint of the line connecting the centers of the two pull-out piles 3. At this time, if a load is applied to the compression pile 2 and the pull-out pile 3, and the force of the support frame 1 is balanced, under the theoretical condition that the deadweight of the support frame 1 is not considered, the force of the compression pile 2 is twice the force of the single pull-out pile 3.

[0055] Reference Figure 1 and Figure 3In another embodiment, one compression pile 2 is provided for the compression test, and four pull-out piles 3 are provided for the pull-out test; and the four pull-out piles 3 are arranged in a rectangular shape, and accordingly, the compression pile 2 is located at the center of the rectangle formed by the four pull-out piles 3. In this embodiment, the coverage surface of the crossbeam 12 in the support frame 1 needs to be adapted to the arrangement position of the four pull-out piles 3. At the same time, if loads are applied to the compression pile 2 and the pull-out pile 3, and the support frame 1 is balanced in force, under the theoretical condition that the deadweight of the support frame 1 is not considered, the force applied to the compression pile 2 is four times the force applied to the single pull-out pile 3.

[0056] In addition, in other embodiments, more than two compression piles 2 may be set as a group of compression piles for compression tests. If more than two compression piles are set, the distance between two adjacent compression piles 2 must be controlled to be no less than three times the diameter of the compression pile 2 and no less than 2m, so as to reduce the disturbance of the soil layer during the compression test and interfere with the test.

[0057] Reference Figure 1 The pressure applying assembly is located between the cross beam 12 and the anti-pressure pile 2, and the number of the pressure applying assembly is the same as the number of the anti-pressure pile 2 and corresponds to each other; specifically, the pressure applying assembly includes four vertically arranged first jacking members 4, and the first jacking members 4 are connected to a control module for controlling the jacking of the first jacking members 4. The four first jacking members 4 are projected onto a horizontal plane to form a third projection figure, and the center of the third projection figure is vertically aligned with the center of the first projection figure.

[0058] At the same time, a pressure plate 41 is installed between the first jacking member 4 and the cross beam 12. The pressure plate 41 is used to transfer the loads applied by the four first jacking members 4 to the cross beam 12, which can reduce the situation where the cross beam 12 is subjected to concentrated force and excessive stress. In addition, in this embodiment, the first jacking member 4 can use a hydraulic jack. Correspondingly, the control module is also connected to a first force monitor, and the load actually output by the first jacking member 4 can be monitored by the first force monitor. Specifically, the first force monitor can use a pressure sensor that matches the first jacking member 4. In actual testing, the first jacking member 4 is used to lift between the cross beam 12 and the anti-pressure pile 2, which can play a role in exerting pressure on the anti-pressure pile 2.

[0059] The pull-out force applying assembly 5 is located between the cross beam 12 and the pull-out pile 3, and the number of the pull-out force applying assembly 5 is the same as the number of the pull-out pile 3 and corresponds to each other. Specifically, the pull-out force applying assembly 5 includes an upper anchor 51, a lower anchor 52, a second jacking member 53 and a tension rod 54. The upper anchor 51 can slide vertically relative to the cross beam 12, and the second jacking member 53 is installed between the upper anchor 51 and the cross beam 12. Accordingly, a cushion block 531 for the second jacking member 53 to press is installed on the cross beam 12, and the output end of the second jacking member 53 presses against the lower surface of the upper anchor 51.

[0060] In this embodiment, the upper anchor 51 can be a grid plate or a flat plate, and the second jacking member 53 can be a hydraulic jack. At the same time, the second jacking member 53 is also connected to a control module for controlling the second jacking member 53 to jack up; accordingly, the control module connected to the second jacking member 53 is also connected to a second force monitor, and the load actually output by the second jacking member 53 can be monitored by the second force monitor. Specifically, the second force monitor can be a pressure sensor matched with the second jacking member 53.

[0061] The lower anchor 52 is fixedly connected to the connecting rib 31 exposed at the upper end of the tensile pile. In this embodiment, the lower anchor 52 is fixed to the connecting rib 31 by welding. At the same time, the tie rod is vertically arranged, and the upper end of the tie rod is connected to the upper anchor 51, and the lower end is connected to the lower anchor 52. In this embodiment, the tie rod is made of high-strength threaded steel, and the end of the tie rod is connected to the upper anchor 51 or the lower anchor 52 through a threaded sleeve 541. In actual testing, the upper anchor 51 is lifted by the second lifting member 53, and the force can be transmitted to the connecting rib 31 at the upper end of the tensile pile 3 through the tie rod and the lower anchor 52.

[0062] In addition, in the actual static load test, it is also necessary to monitor and record the displacement parameters of the compression pile 2 and the pull-out pile 3 after being subjected to force; specifically, a vertical reference pile 6 and a reference beam 61 laterally connected to the reference pile 6 can be set on one side of each compression pile 2 and each pull-out pile, and a displacement sensor for monitoring the displacement of the pile body can be installed on the reference pile 6 and the reference beam 61; and the displacement sensor can also be connected to the processor, and the monitoring time of the displacement sensor can be adjusted by the processor, and the monitoring data of the displacement sensor can be recorded and stored for subsequent analysis and processing.

[0063] The implementation principle of the anchor pile reaction system for the synchronous static load test of compressive and tensile bearing capacity in the embodiment of the present application is:

[0064] First, the test area is selected, and then the compression piles 2 and the pull-out piles 3 are cast in the soil; then, the support frame 1 is installed in the test area, and then the pressure applying assembly and the pull-out force applying assembly 5 are installed. During the test, the pressure applying assembly is used to apply pressure to the compression pile 2, and the pull-out force is applied to the pull-out pile 3 by the pull-out force applying assembly 5. At the same time, the force values ​​of the pressure applying assembly and the pull-out force applying assembly 5 are monitored to maintain the load value required during the actual static load test; and the force values ​​of the above two can also be adjusted to maintain the stability of the support frame 1, and the compression test of the compression pile 2 and the pull-out test of the pull-out pile 3 are carried out simultaneously.

[0065] The actual load application process of the compression test and the pull-out test adopts a graded loading method, which is divided into 15 levels of loading in total, and the loading is equal at each level; the graded load should be 1 / 15 of the maximum load or the estimated ultimate bearing capacity, and the first level loading can be twice the graded loading; unloading should be graded unloading, and the unloading amount of each level should be twice the graded load during loading, and it should be unloaded equally at each level.

[0066] The pressure sensor and the displacement sensor are used to automatically monitor and record the displacement values ​​and loads of the compression pile 2 and the pull-out pile 3.

[0067] The embodiment of the present application also discloses a method for synchronous static load test of compressive and tensile bearing capacity, which adopts one of the above-mentioned synchronous static load test anchor pile reaction systems for compressive and tensile bearing capacity; specifically, the method for synchronous static load test of compressive and tensile bearing capacity comprises the following steps:

[0068] S1. Preliminary preparation: select the test area, plan the layout of the compression piles 2 and the pull-out piles 3 in the static load test, and determine the setting points of each compression pile 2 and pull-out pile 3 in the test area based on the layout plan.

[0069] The layout plan includes the number, spacing and arrangement of the compression piles 2 and the pull-out piles 3 .

[0070] Specifically, if the number of compression piles 2 is set to one and the number of pull-out piles 3 is set to two, the three piles are arranged along a straight line, and the compression pile 2 is located at the midpoint of the line connecting the centers of the two pull-out piles 3; if the number of compression piles 2 is set to one and the number of pull-out piles 3 is set to four, the four pull-out piles 3 are arranged as the four corner points of a rectangle, and accordingly, the compression pile 2 is located at the center of the rectangle formed by the four pull-out piles 3.

[0071] In addition, the distance d between the compression pile 2 and the pull-out pile 3 is not less than three times the maximum pile diameter of the compression pile 2 and the pull-out pile 3, and the distance d is ≥ 2 m.

[0072] S2. Equipment installation: based on the layout plan, compression piles 2 and pull-out piles 3 are set up at the setting points accordingly, a support frame 1 is erected in the test area, a pressure application component and a first force monitor are installed between the support frame 1 and the compression piles 2, and a pull-out force application component 5 and a second force monitor are installed between the support frame 1 and the pull-out piles 3.

[0073] Among them, the support frame 1 includes a crossbeam 12, and the pressure applying component and the pull force applying component 5 both apply force in the vertical direction. When the pressure applying component applies force to the anti-pressure pile 2, it will apply an upward lifting force to the crossbeam 12, and when the pull force applying component 5 applies force to the anti-pulling pile 3, it will apply a downward resistance force to the crossbeam 12.

[0074] S3, load loading, use the pressure applying component to apply pressure load to the anti-compression pile 2, use the pull-out force applying component 5 to apply pull-out load to the pull-out pile 3, the pressure load and the pull-out load are loaded equally step by step, and there are 15 levels of loading in total, the graded load is 1-1.5 times 1 / 15 of the estimated ultimate load, and each level of loading is maintained for 1-1.5 hours. During the load maintenance process, the vertical displacements of the anti-compression pile 2 and the pull-out pile 3 are measured and recorded.

[0075] Among them, during the load loading and load maintenance process, the pressure load M and the pull-out load N satisfy the relationship: when M0≤N0, |a Mb N|≤M0 / 15; when M0>N0, |a Mb N|≤N0 / 15; in the above, a represents the number of compression piles 2, b represents the number of pull-out piles 3, M0 represents the estimated ultimate load of the compression pile 2, and N0 represents the estimated ultimate load of the pull-out pile 3.

[0076] S4, load unloading, gradually unloading the load on the compression pile 2 and the pull-out pile 3, after unloading to zero, dismantling the equipment.

[0077] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A synchronous static load test method for compressive and tensile bearing capacity, characterized in that: include: Support frame (1); A compression pile group is vertically connected to the soil, and the compression pile group is projected onto a horizontal plane to form a first projection figure; An anti-pullout pile group is vertically connected to the soil, and the anti-pullout pile group is projected onto a horizontal plane to form a second projection figure, wherein the center of one of the first projection figure and the second projection figure is located within the other; A pressure applying assembly is vertically arranged between the support frame (1) and the compression pile group, and is used to drive the support frame (1) and the compression pile group away from each other; A first force monitor, used to monitor the force value of the pressure applying component; A pull-out force applying assembly (5) is vertically arranged between the support frame (1) and the pull-out pile group, and is used to drive the support frame (1) and the pull-out pile group to move closer to each other; A second force monitor, used for monitoring the force value of the pulling force applying component (5); The support frame (1) comprises a vertically arranged pier (11) and a horizontally arranged crossbeam (12); wherein the number of the piers (11) is multiple, and the crossbeam (12) is erected on the piers (11), so that the crossbeam (12) is stably erected through the piers (11); The following steps are involved: S1, preliminary preparation, selecting a test area, planning a layout scheme of the compression piles (2) and the pull-out piles (3) in the static load test, and determining the setting points of each compression pile (2) and the pull-out pile (3) in the test area based on the layout scheme; wherein the layout scheme includes the number, spacing and arrangement of the compression piles (2) and the pull-out piles (3); S2, equipment installation, based on the layout plan, anti-compression piles (2) and anti-pulling piles (3) are correspondingly set at the setting points, a support frame (1) is erected in the test area, a pressure applying component and a first force monitor are installed between the support frame (1) and the anti-compression piles (2), and a pull-out force applying component (5) and a second force monitor are installed between the support frame (1) and the anti-pulling piles (3); wherein the support frame (1) includes a crossbeam (12), the pressure applying component and the pull-out force applying component (5) both apply force in the vertical direction, and when the pressure applying component applies force to the anti-compression pile (2), it applies an upward lifting force to the crossbeam (12), and when the pull-out force applying component (5) applies force to the anti-pulling pile (3), it applies a downward resisting force to the crossbeam (12); S3, load loading, using the pressure applying assembly to apply a pressure load to the compression pile (2), and using the pull-out applying assembly (5) to apply a pull-out load to the pull-out pile (3), the pressure load and the pull-out load are both loaded step by step in equal amounts, and a total of 15 levels of loading, the graded load is 1 / 15 of 1-1.5 times the estimated limit load, and each level of loading is maintained for 1-1.5 hours. During the load maintenance process, the vertical displacements of the compression pile (2) and the pull-out pile (3) are measured and recorded; S4, load unloading, gradually unloading the load on the compression pile (2) and the pull-out pile (3), and after unloading to zero, dismantling the equipment; During the load loading and load maintenance process of step S3, the pressure load M and the pull-out load N satisfy the relationship: when M0≤N0, |a Mb N|≤M0 / 15; when M0>N0, |a Mb N|≤N0 / 15; wherein a represents the number of compression piles (2), b represents the number of pull-out piles (3), M0 represents the estimated ultimate load of the compression piles (2), and N0 represents the estimated ultimate load of the pull-out piles (3).

2. The method for synchronous static load test of compressive and tensile bearing capacity according to claim 1, characterized in that: The center of the first projection figure is vertically aligned with the center of the second projection figure.

3. The method for synchronous static load test of compressive and tensile bearing capacity according to claim 1, characterized in that: The compression pile group comprises a compression pile (2), and the pull-out pile group comprises two pull-out piles (3). The compression pile (2) and the pull-out piles (3) are arranged along a straight line, and the compression pile (2) is located at the midpoint of the line connecting the two pull-out piles (3).

4. The method for synchronous static load test of compressive and tensile bearing capacity according to claim 1, characterized in that: The compression pile group comprises a compression pile (2), and the pull-out pile group comprises four pull-out piles (3). The four pull-out piles (3) are arranged in a rectangular shape, and the compression pile (2) is located at the center of the rectangle formed by the four pull-out piles (3).

5. The method for synchronous static load test of compressive and tensile bearing capacity according to claim 3 or 4, characterized in that: The distance d between the compression pile (2) and the pull-out pile (3) is not less than three times the maximum pile diameter of the compression pile (2) and the pull-out pile (3), and the distance d is ≥ 2 m.

6. The method for synchronous static load test of compressive and tensile bearing capacity according to claim 2, characterized in that: The pressure applying assembly comprises a plurality of first lifting members (4), wherein the first lifting members (4) are connected to a control module for controlling the first lifting members (4) to perform lifting, and the plurality of first lifting members (4) are projected on a horizontal plane to form a third projection pattern, wherein the center of the third projection pattern is vertically aligned with the center of the first projection pattern.

7. The method for synchronous static load test of compressive and tensile bearing capacity according to claim 1, characterized in that: The pull force applying assembly (5) comprises an upper anchor (51), a lower anchor (52), a second jacking member (53) and a tension rod (54); the upper anchor (51) is vertically slidably connected to the support frame (1); the lower anchor (52) is connected to the pile body in the pull-out pile group; the second jacking member (53) is arranged between the upper anchor (51) and the support frame, and the second jacking member (53) is used to drive the upper anchor (51) and the support frame away from each other; the tension rod (54) is vertically arranged, and the upper end of the tension rod (54) is connected to the upper anchor (51), and the lower end is connected to the lower anchor (52).

8. The method for synchronous static load test of compressive and tensile bearing capacity according to claim 7, characterized in that: The pile body in the pull-out resistant pile group is provided with vertical connecting ribs (31), and the lower anchor (52) is fixedly connected to the connecting ribs (31).

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