Device for testing bearing performance of pile foundation under simulated filling consolidation effect

Abstract

The utility model discloses a device for testing the bearing performance of a pile foundation under the simulated filling consolidation effect, which relates to the technical field of foundation engineering and comprises a model box, and the bottom of the model box is fixedly arranged on a base; a positioning column is arranged in the model box, a first loading disc is fixed to the top of the positioning column, an undisturbed soil layer is arranged between the first loading disc and the bottom in the model, and a backfill soil layer is arranged between the first loading disc and the top end of the model box; at least one second loading disc is arranged in the backfill soil layer space, a plurality of mounting holes are reserved in the second loading disc and the first loading disc, a drawing steel cable penetrating through the mounting holes is arranged in the model box, and the bottom of the drawing steel cable is connected with a loading device; a limiting stopper is fixed on the drawing steel cable, the limiting stopper can penetrate through the mounting hole together with the drawing steel cable when being closed, and the limiting stopper is matched with the mounting hole to limit the displacement of the loading disc when being opened; the loading mode and structure are simplified, quantitative load application can be rapidly and accurately achieved, and the accuracy of a simulation test is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of foundation engineering, in particular to a pile foundation bearing performance test device under simulated fill consolidation effect. Background Art

[0002] Pile foundation is the most commonly used foundation type in engineering. When pile foundation is used in fill strata, the pile foundation will bear the negative friction caused by the consolidation of fill soil. Negative friction has a serious weakening effect on the bearing capacity of the pile foundation. Therefore, it is particularly important to explore the influence of negative friction of pile foundation on its bearing capacity. The test method is an effective method to analyze the influence of negative friction of pile foundation on the bearing capacity of pile foundation, which can be observed more intuitively through the test. Some existing test devices cause the soil to settle by directly applying load on the upper part. This test process has the defect of being inconsistent with the actual engineering, which makes the test results have systematic errors.

[0003] Patent 202311802047.5 discloses a test device and method for pile foundation bearing performance under simulated fill consolidation effect, which overcomes the above-mentioned defects, can distinguish between the original soil layer and the fill, and more realistically simulate the influence of negative friction on the pile foundation bearing capacity under the fixed effect of the fill layer. However, it is found in engineering practice that since the loading process of this technology needs to be assisted by an annular body and an elastic loading strip, and the elastic loading strip cannot meet the test requirements of accurate and quantitative control of loading pressure, this solution still has defects in realizing accurate simulation tests, and this test device is relatively large in size and complicated to operate. Utility Model Content

[0004] In view of the deficiencies in the above-mentioned prior art, the utility model provides a pile foundation bearing performance test device under simulated fill consolidation effect, which can not only truly simulate the influence of negative friction resistance generated by fill consolidation on the pile foundation in actual engineering, but also simplifies the loading method and structure, and can quickly and accurately realize quantitative load application, thereby further realizing high-precision simulation tests.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A pile foundation bearing performance test device under simulated fill consolidation effect, comprising a model box, the bottom of the model box is fixedly arranged on a base; a positioning column fixed on the base is arranged in the model box, a first loading disc is fixed on the top of the positioning column, an original soil layer is between the first loading disc and the bottom of the model, and a backfill soil layer is between the first loading disc and the top of the model box;

[0007] At least one second loading disc is provided in the backfill soil layer space, and a plurality of mounting holes are reserved on the second loading disc and the first loading disc. A pull-out steel cable passing through the mounting holes is provided in the model box, and a loading device is connected to the bottom of the pull-out steel cable. A plurality of limiters of different heights are fixed on the pull-out steel cable, and when the limiter is closed, the pull-out steel cable can pass through the mounting hole, and when the limiter is opened, it cooperates with the mounting hole to limit the displacement of the loading disc.

[0008] Preferably, the plurality of mounting holes are evenly distributed along the circumference of the loading disc.

[0009] Preferably, the loading device is arranged at the bottom of the base; the loading device adopts a pull-through jack, which can apply downward pressure to the pull-through cable to drive the loading disc to move downward, to compress the backfill soil layer inside the box to simulate the consolidation effect of the fill.

[0010] Preferably, the first loading disc and the second loading disc are coaxially arranged to facilitate simulation of stability during sedimentation.

[0011] Preferably, the first loading disc is connected to the positioning column bolts.

[0012] Preferably, the top of the pulling cable is connected to the second loading disc, and the bottom passes through the base to be connected to the loading device.

[0013] Preferably, the limiter is coaxially arranged with the pulling steel cable, and the limiter is a steel component, including a fixing part and a limiting part, and the fixing part and the limiting part are hingedly connected, and the tensioning or closing state switching of the limiting part is achieved through a hinge structure.

[0014] Preferably, the limiting portion is arranged on the outer periphery of the fixing portion, and the limiting portion is provided with at least two wings, and the limiting portion is in close contact with the side disc body of the loading disc when it is opened.

[0015] Preferably, an axial hole is coaxially opened at the center of the first loading disc and the second loading disc, and a simulated pile body is longitudinally arranged in the axial hole to facilitate observation of changes in the bearing performance of the pile body when the backfill soil layer settles.

[0016] Preferably, the loading disc is made of lightweight steel, has a light weight, can reduce the test error caused by its own weight, and has a strong deformation resistance, can ensure the service life of multiple tests.

[0017] By adopting the above technical solution, the beneficial effects of the utility model are as follows:

[0018] 1. The utility model cooperates with the positioning column, the loading disc, the pulling steel cable and the limiter. On the one hand, it can distinguish the backfill soil layer and the original soil layer, and truly simulate the pile foundation in the actual project to be only affected by the negative friction resistance generated by the backfill consolidation, thereby improving the accuracy of the test results; on the other hand, it simplifies the loading method and structure, and can quickly and accurately realize the quantitative load application, further improving the accuracy of the simulation test.

[0019] 2. After the utility model locates the position of the loading disc by means of the positioning column and the limiter, the through-hole jack loading can only pressurize the soil between the loading discs to achieve the purpose of simulating the consolidation effect of the fill, and more realistically reflects the influence of the consolidation effect of the fill on the bearing capacity of the pile foundation.

[0020] 3. The properties of the backfill soil layer of the utility model can be arbitrarily changed according to the needs of the test; at the same time, the utility model can change the jack tensioning rate to control the soil consolidation rate, which can more realistically reflect the phenomenon occurring when various soils produce consolidation effects, and has good applicability.

[0021] 4. The utility model has a simple structure, occupies a small volume, and has a low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0023] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0024] Figure 2 This is a schematic diagram of the internal structure of the utility model;

[0025] Figure 3 This is the front view of the utility model;

[0026] Figure 4 This is the internal front view of the utility model;

[0027] Figure 5 This is a schematic diagram of the structure of the limiter of the utility model;

[0028] Figure 6 This is a schematic diagram of the opening of the limiter of the utility model;

[0029] Figure 7 This is a schematic diagram of the closing of the limiter of the utility model.

[0030] In the figure: 1. model box; 2. base; 3. pull-out through-type jack; 4. pull-out steel cable; 5. first loading disc; 6. second loading disc; 7. positioning column; 8. limiter; 81. fixing part; 82. limiting part; 9. original soil layer; 10. backfill soil layer; 11. simulated pile body. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0033] Embodiment 1

[0034] In a typical embodiment of the present application, a pile foundation bearing performance test device simulating the fill consolidation effect is provided, such as Figure 1-5 As shown, it includes a model box 1, the bottom of which is fixedly arranged on a base 2; a positioning column 7 fixed on the base is arranged inside the model box 1, a first loading disc 5 is fixed on the top of the positioning column, an original soil layer 9 is between the first loading disc and the bottom of the model box, and a backfill soil layer 10 is between the first loading disc and the top of the model box.

[0035] like Figure 2 , 4 As shown, at least one second loading disc 6 is provided in the backfill soil layer space, and multiple mounting holes are reserved on the second loading disc 6 and the first loading disc 5. The first loading disc and the second loading disc are collectively referred to as loading discs, and have the same structure in this embodiment. A pull-out steel cable 4 passing through the mounting hole is provided in the model box, and a loading device is connected to the bottom of the pull-out steel cable; multiple limiters 8 at different heights are fixed on the pull-out steel cable 4, and when the limiter is closed, it can pass through the mounting hole together with the pull-out steel cable 4, and when the limiter is opened, it cooperates with the mounting hole to limit the displacement of the loading disc.

[0036] like Figure 1 , 2As shown, in this embodiment, a plurality of mounting holes are evenly distributed along the circumference of the loading disc to ensure that pulling the steel cable can drive the loading disc to settle evenly.

[0037] In this embodiment, the loading device is arranged at the bottom of the base, which can save installation space. In order to facilitate the cooperation with the pulling cable, the loading device adopts a pulling through-type jack, such as Figure 4 As shown, the top of the pull-through jack 3 is connected to the bottom of the pull-through cable 4, and downward pressure can be applied to the pull-through cable to drive the loading disc to move downward, so as to compress the backfill soil layer inside the box to simulate the consolidation effect of the backfill soil. Specifically, the top of the pull-through cable 4 is connected to multiple second loading discs 6 through a limiter, the top of the pull-through cable is connected to the second loading disc at the top, and the bottom passes through the reserved cable hole on the base and is connected to the pull-through jack 3, so as to achieve vertical loading.

[0038] like Figure 2 , 4 As shown, the first loading disc 5 and the second loading disc 6 are coaxially arranged to facilitate simulating stability during the sedimentation process.

[0039] In the present embodiment, the first loading disc 5 is bolted to the positioning column 7. Specifically, a bolt hole is provided on the upper part of the positioning column 7, and the first loading disc 5 located at the bottom of the backfill soil layer is fixed by bolting to the positioning column through the bolt hole, so that the original soil layer and the backfill soil layer are distinguished by the first loading disc. During the simulation test, the load is only applied downward to the backfill soil layer to simulate the consolidation settlement characteristics of the fill. When the steel cable is pulled to drive the second loading disc to move downward, the second loading disc loads the backfill soil layer below it, generating negative friction resistance. In the present embodiment, multiple second loading discs 6 are distributed in multiple layers at different heights, so that layered settlement can be achieved. In the present embodiment, both the first loading disc and the second loading disc are made of lightweight steel, which has the advantage of being light in weight, which can reduce the test error caused by the deadweight of the loading disc, and has strong anti-deformation ability, ensuring the service life of multiple tests.

[0040] like Figure 2 , 4 As shown, an axial hole is coaxially opened at the center of the first loading disc 5 and the second loading disc 6, and a simulated pile body 11 is longitudinally arranged in the axial hole. The simulated pile body 11 is located in the backfill soil layer 10 between the first loading disc and the second loading disc on the top, so as to facilitate the observation of the change of the bearing performance of the pile body when the backfill stratum settles.

[0041] like Figure 5-7As shown, the limiter 8 is coaxially arranged with the pulling steel cable 4. The limiter is a steel component, specifically including a fixed portion 81 and a limiter 82 connected to the outer periphery of the fixed portion. The fixed portion 81 and the limiter 82 are hingedly connected. The limiter is provided with at least two wings. When the limiter is opened, it is in close contact with the side plate body of the loading disc. In this embodiment, a four-wing limiter is adopted. The four-wing limiters are evenly distributed around the fixed portion and are hingedly connected to the fixed portion through a hinge assembly, so that the limiter can be rotated and folded; the loading disc is in a closed state after assembly. When the limiter is required, the limiter is opened upward by opening and closing the hinge structure, and is in close contact with the side plate body at the loading disc installation hole, so that the loading disc can be driven downward when the pulling steel cable is lowered, simulating the sinking process.

[0042] The test steps of this embodiment are as follows:

[0043] Step 1: Install the corresponding model box and the positioning columns of the corresponding height according to the thickness of the original soil layer and the backfill soil layer required by the test to form the main structure of the lower original soil layer and the upper backfill soil layer; connect the first loading disc to the positioning column through bolts, and after fixing, pass the pulling steel cable through the reserved installation hole.

[0044] Step 2: Fill the model box with the original soil layer of corresponding height, install the stress sensor on the simulated pile body, and then bury the bottom of the simulated pile body in the original soil layer to fix the pile body.

[0045] Step 3: Backfill the soil layer into the model box layer by layer, fill the first layer of soil to the height of the upper limiter on the pulling cable, and install a second loading disc. At this time, the limiter is closed; the limiter passes through the installation hole of the second loading disc and then opens, and the four-wing limit part fits with the loading disc body, thereby limiting the displacement of the second loading disc.

[0046] Step 4: Fill multiple groups of soil according to step 3, and assemble the second loading disc until the top of the model box.

[0047] Step 5: Start the pull-through jack to make the pull-through cable move vertically downward, and use the limiter to drive the second loading disc to compress the backfill soil layer, so as to drive the backfill soil layer to undergo a settlement effect similar to that when consolidation occurs.

[0048] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Those skilled in the art should understand that the utility model can be modified and varied in various ways. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A pile foundation bearing performance test device simulating fill consolidation effect, characterized in that: The model box comprises a model box, the bottom of which is fixedly arranged on a base; a positioning column fixed on the base is arranged inside the model box, a first loading disc is fixed on the top of the positioning column, an original soil layer is between the first loading disc and the bottom of the model, and a backfill soil layer is between the first loading disc and the top of the model box; At least one second loading disc is provided in the backfill soil layer space, and a plurality of mounting holes are reserved on the second loading disc and the first loading disc. A pull-out steel cable passing through the mounting holes is provided in the model box, and a loading device is connected to the bottom of the pull-out steel cable. A plurality of limiters of different heights are fixed on the pull-out steel cable, and when the limiter is closed, the pull-out steel cable can pass through the mounting hole, and when the limiter is opened, it cooperates with the mounting hole to limit the displacement of the loading disc.

2. A pile foundation bearing performance test device under simulated fill consolidation effect as claimed in claim 1, characterized in that: A plurality of mounting holes are evenly distributed along the circumference of the loading disc.

3. A pile foundation bearing performance test device under simulated fill consolidation effect as claimed in claim 1, characterized in that: The loading device is arranged at the bottom of the base; the loading device adopts a pull-through jack.

4. A pile foundation bearing performance test device for simulating fill consolidation effect as claimed in claim 1, characterized in that: The first loading disc is coaxially arranged with the second loading disc.

5. A pile foundation bearing performance test device for simulating fill consolidation effect as claimed in claim 4, characterized in that: The first loading disc is connected with the positioning column bolts.

6. A pile foundation bearing performance test device for simulating fill consolidation effect as claimed in claim 1, characterized in that: The top of the pulling cable is connected to the second loading disc, and the bottom passes through the base and is connected to the loading device.

7. A pile foundation bearing performance test device for simulating fill consolidation effect as claimed in claim 1, characterized in that: The limiter is coaxially arranged with the pulling steel cable. The limiter is a steel component, comprising a fixing part and a limiting part, and the fixing part and the limiting part are hingedly connected.

8. A pile foundation bearing performance test device for simulating fill consolidation effect as claimed in claim 7, characterized in that: The limiting portion is arranged on the periphery of the fixing portion, and the limiting portion is provided with at least two wings. When the limiting portion is opened, it is in close contact with the side disc body of the loading disc.

9. A pile foundation bearing performance test device under simulated fill consolidation effect as claimed in claim 1, characterized in that: An axial hole is coaxially opened at the center of the first loading disc and the second loading disc, and a simulated pile body is longitudinally arranged in the axial hole.

10. A pile foundation bearing performance test device for simulating fill consolidation effect as claimed in claim 1, characterized in that: The loading disc is made of light steel.

Images