Special-shaped stirring test pile, test device and test method

Abstract

The application discloses a special-shaped stirring test pile, a test device and a test method, which separates the internal space of the pile body into multiple independent chambers through a partition, forms multiple expansion spaces corresponding to the chambers one by one through an elastic membrane sealing on the outer periphery of the pile body, connects the expansion space and the chamber of the corresponding layer through a via hole arranged on the circumferential wall of the pile body, sets a disturbing part outside the elastic membrane, which can stretch in the radial direction of the pile body and extrude into the soil, and connects the chamber and a high-pressure fluid source through a first high-pressure fluid conveying pipe. The application can drive the radial expansion of the elastic membrane of the corresponding layer according to the test working condition and requirement, form a predetermined T-shaped, cross-shaped or inverted T-shaped special-shaped pile shape, meet the test pile requirement of different shapes, support the test soil during the grouting process, thus prevent the occurrence of the conditions of hole collapse and pile body deformation, improve the pile forming quality, improve the test efficiency and test effect, and further better provide reference or help for the treatment of soft foundation.

Description

Technical Field

[0001] This invention relates to the field of irregular-shaped mixing pile testing technology, and particularly to an irregular-shaped mixing test pile, a test device, and a test method. Background Technology

[0002] In the coastal and inland regions of eastern my country with well-developed river systems such as rivers and lakes, the abundant thick soft soil layers are characterized by low strength, large settlement deformation, and poor stability. Effectively treating and reinforcing thick soft soil foundations (referred to as soft soil foundations) is a major technical challenge in infrastructure construction such as rail transit, highways, railways, airports, and municipal projects. Since the introduction of the mixing pile method in China in 1978, extensive construction practice has been conducted. The mixing pile method has gradually developed in soft soil foundation treatment, and today it is no longer limited to uniform diameter piles but has evolved into more complex irregular-shaped piles such as T-shaped piles, cross piles, and inverted T-shaped piles with locally expanded diameters.

[0003] To provide reference or assistance for the treatment of soft soil foundations, some domestic research institutions have conducted numerous indoor model tests on mixing piles. Existing indoor tests of irregularly shaped mixing piles (especially cruciform or inverted T-shaped piles) are generally based on piles of equal diameter. Specifically, the pile of equal diameter is first placed in a model box and backfilled and compacted in layers; then, the pile is pulled out of the test soil to form a primary pit; next, according to the test requirements, the primary pit is locally enlarged and cleaned using tools to transform it into the irregularly shaped pit required for the test; then, the irregularly shaped pit is grouted and left to stand for a predetermined time (e.g., 28 days), after which the parameters of the treated test soil (such as strength) are studied and analyzed to provide some reference or assistance for the actual treatment of soft soil foundations using mixing piles. However, the existing indoor model test method for irregularly shaped mixing piles still has shortcomings, such as: 1. The method of forming an irregular pit and then injecting grout into it cannot disturb the test soil during the grouting process, resulting in the grout not being able to diffuse to the soil around the irregular pit. This limits the treatment and reinforcement range of the test soil, which is far from the actual treatment and reinforcement range of mixing piles. As a result, it is easy to have unstable pile quality, poor pile quality, and low pile strength. It has a weak reference or assistance role for the actual treatment of soft soil mixing piles, and the test results are relatively poor. 2. The method of first pulling the pile, then locally expanding the diameter and cleaning the hole to form an irregular hole, and then injecting grout, is prone to collapse and pile deformation during the pile formation process. It also has the disadvantages of being cumbersome, inefficient, and having poor test results. Summary of the Invention

[0004] The main objective of this invention is to provide an irregularly shaped mixing test pile, a test device, and a test method, aiming to improve the test effect and test efficiency.

[0005] To achieve the above objectives, the present invention proposes an irregularly shaped mixing test pile, comprising:

[0006] The pile body is hollow inside, and multiple partitions are axially spaced inside the hollow body to divide the internal space of the pile body into multiple independent chambers.

[0007] An elastic membrane is fixed to the outer periphery of the pile body and seals and surrounds the area of ​​each cavity on the outer periphery of the pile body, forming a multi-layer controllable expansion space. The peripheral wall of the pile body is also formed with through holes that connect the corresponding cavities and expansion spaces.

[0008] The first high-pressure fluid delivery pipe has an outlet end connected to the chamber and an inlet end connected to an external high-pressure fluid source.

[0009] Multiple disturbance elements, located outside the elastic membrane, can extend and penetrate the test soil in the radial direction of the pile. When the pile rotates under the drive of an external driving mechanism, the disturbance elements can rotate with the pile and stir the surrounding soil; and

[0010] The grouting pipe has one end extending to the outside of the pile body and / or elastic membrane, and the other end can be connected to an external grouting device for grouting the test soil.

[0011] The present invention also proposes an irregularly shaped stirring test apparatus, comprising:

[0012] Model box, which is used to hold the test soil;

[0013] Test pile, wherein the test pile is the aforementioned test pile;

[0014] A high-pressure fluid source is connected to the inlet end of the first high-pressure fluid delivery pipe;

[0015] The grouting device is connected to the other end of the grouting pipe; and

[0016] A drive mechanism, which is connected to the test pile, is used to drive the test pile to rise, fall, and rotate.

[0017] This invention also proposes a method for conducting irregular stirring tests, comprising the following steps:

[0018] S1. According to the test conditions and requirements, high-pressure fluid is introduced into the corresponding one or more chambers, and the elastic membrane of the corresponding layer is driven to expand radially.

[0019] S2. Place the test pile in the test soil and compact it;

[0020] S3. Drive the test pile to rotate so that the disturbance component mixes the surrounding soil and grouts the test soil.

[0021] S4. Reduce or remove the fluid pressure on the expansion space, causing the elastic membrane to contract radially;

[0022] S5. Combine the grouting speed with the slow lifting of the test pile until the overall pouring of the irregular pile is completed and the test pile is completely separated from the test soil.

[0023] The technical solution of this invention divides the internal space of the pile into multiple independent chambers by means of a partition plate, and forms multiple expansion spaces corresponding to the chambers by means of an elastic membrane sealing the outer periphery of the pile. The expansion spaces and chambers of the corresponding layers are connected by through holes provided on the periphery of the pile. A disturbance element that can stretch and squeeze into the soil in the radial direction of the pile is provided on the outside of the elastic membrane, and the chambers are connected to the high-pressure fluid source by means of a first high-pressure fluid delivery pipe. This invention allows for the following process during testing: First, high-pressure fluid is introduced into one or more chambers according to the test conditions and requirements, causing the elastic membranes of the corresponding layers to expand radially, forming predetermined T-shaped, cross-shaped, or inverted T-shaped irregular piles. This satisfies the needs of test piles with different shapes without the need to manufacture different irregular piles separately, offering good versatility and saving on test pile manufacturing costs. Next, the test pile is placed in the test soil, and the soil is compacted from the top. Then, the test pile is driven to rotate via a drive mechanism, causing the agitator to stir the surrounding soil and inject grout. The agitator, in its extended state, disturbs the surrounding soil, allowing the grout to diffuse into the surrounding soil and making the grout and soil more closely integrated, thereby improving the reinforcement effect and increasing the treatment and reinforcement range of the test soil. Finally, the pressure is lowered or... The fluid pressure applied to the expansion space is removed, causing the elastic membrane to contract radially under its own rebound force and the pressure difference between the inside and outside of the expansion space. This forces the fluid in the expansion space and chamber to flow out through the first high-pressure fluid delivery pipe. The gap between the elastic membrane and the test soil after contraction is filled with grout. After the elastic membrane has basically completely contracted, the test pile is slowly lifted and grouting is maintained in conjunction with the grouting speed. This allows the grout to fill the voids formed by the slow lifting of the test pile in a timely manner until the test pile is completely detached from the test soil and the overall casting of the irregular pile is completed. Since the test pile can support the test soil on its outer periphery during the lifting and grouting process, it can prevent the collapse of the pile and the deformation of the pile body, improve the quality of the pile, and enhance the test efficiency and effect. This can better provide reference or assistance for the treatment of soft soil foundations. Attached Figure Description

[0024] Figure 1 This is a three-dimensional schematic diagram of the irregularly shaped mixing test pile (without radial grouting pipes installed) of the present invention;

[0025] Figure 2 , Figure 3 This is a longitudinal sectional view of the irregularly shaped mixing test pile (without radial grouting pipe installed) of the present invention in two perpendicular directions;

[0026] Figure 4 This is a partial schematic diagram of the irregularly shaped mixing test pile of the present invention after radial expansion of an elastic membrane;

[0027] Figure 5 This is an exploded view of the elastic membrane and the cylinder.

[0028] Figure 6 This is a schematic diagram of the irregularly shaped mixing test pile of the present invention buried in the test soil. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0031] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0032] This invention proposes an irregularly shaped mixing test pile.

[0033] In embodiments of the present invention, such as Figures 1 to 6As shown, the irregularly shaped mixing test pile includes a pile body 1, an elastic membrane 2, a first high-pressure fluid delivery pipe 3, multiple disturbance components 4, and a grouting pipe 5. The pile body 1 is hollow, and multiple partitions 10 are spaced axially (or vertically) within the hollow interior to divide the internal space of the pile body 1 into multiple independent chambers 100. The elastic membrane 2 is fixed to the outer periphery of the pile body 1, sealing and surrounding the area corresponding to each chamber 100 on the outer periphery of the pile body 1, thus forming multiple controllable expansion spaces 20 between the elastic membrane 2 and the outer peripheral wall of the pile body 1. The peripheral wall of the pile body 1 also has through holes 11 that connect the corresponding chambers 100 and expansion spaces 20, allowing high-pressure fluid to flow between the corresponding chambers 100 and expansion spaces 20 through the holes 11, and enabling the expansion and contraction of the elastic membrane 2. The outlet end of the first high-pressure fluid delivery pipe 3 is connected to the chamber 100, and the inlet end is used to connect to an external high-pressure fluid source (not shown). The high-pressure fluid source can be a high-pressure pump that can provide high-pressure gas or a hydraulic pump that can provide high-pressure liquid, etc. The high-pressure fluid source can deliver fluid at the required pressure to the chamber 100 according to the test requirements. The disturbance element 4 is located outside the elastic membrane 2 and can extend and squeeze into the test soil in the radial direction of the pile body 1. When the pile body 1 rotates under the drive of the external drive mechanism, the disturbance element 4 can rotate with the pile body 1 and stir the surrounding soil. One end of the grouting pipe 5 extends to the outside of the pile body 1 and / or the elastic membrane 2, and the other end can be connected to an external grouting device for grouting the test soil.

[0034] During the experiment, high-pressure fluid is first introduced into one or more chambers 100 according to the experimental conditions and requirements, causing the elastic membrane 2 of the corresponding layer to expand radially, forming a predetermined T-shape or cross-shape (see...). Figure 6Alternatively, irregularly shaped piles such as inverted T-shapes can be used to meet the needs of test piles with different shapes, without the need to manufacture different irregularly shaped piles separately. This provides good versatility and saves on the manufacturing cost of test piles. Next, the test pile is placed in the test soil and the test soil is compacted from the top surface. Immediately afterwards, the test pile is driven to rotate by the drive mechanism to drive the disturbance component 4 to stir the surrounding soil and inject grout into the test soil. The disturbance component in the stretched state drives the surrounding soil to be disturbed, so that the grout can diffuse into the surrounding soil and make the grout and soil more closely integrated, thereby improving the reinforcement effect and increasing the treatment and reinforcement range of the test soil. Then, the fluid pressure applied to the expansion space 20 is reduced or removed, so that the elastic membrane 2 is subjected to its own rebound force and the pressure difference inside and outside the expansion space (Note: the pressure borne by the elastic membrane). Under the action of external pressure (including grout pressure, etc.), the test pile contracts radially and forces the fluid in the expansion space 20 and chamber 100 to flow out through the first high-pressure fluid delivery pipe 3. The gap between the elastic membrane 2 and the test soil after contraction is filled by grout. After the elastic membrane 2 has basically completely contracted, the test pile is slowly lifted and grouting is maintained in combination with the grouting speed, so that the grout can fill the voids formed by the slow lifting of the test pile in time, until the test pile is completely removed from the test soil and the overall casting of the irregular pile is completed. Since the test pile can support the test soil on the outer periphery during the lifting and grouting filling of the voids, it can prevent the collapse of the voids and the serious deformation of the pile body, improve the quality of the pile, and improve the test efficiency and test effect, thus providing a better reference or help for the treatment of soft soil.

[0035] In this embodiment of the invention, the pile body 1 is hollow rod-shaped. The pile body 1 can be a one-piece structure or composed of multiple connected segments. In a preferred embodiment, the pile body 1 adopts a multi-segment structure, including multiple vertically stacked and fixedly connected top-opening cylinders 1a. Two vertically adjacent cylinders 1a are fixedly connected. The bottom plate of the cylinder 1a forms the partition 10, which divides the internal space of the two vertically adjacent cylinders 1a to form multiple layers of chambers 100. The partition 10 located between two vertically adjacent cylinders 1a is provided with a connection hole 101 for installing a corresponding first high-pressure fluid delivery pipe 3, so that the outlet end of the first high-pressure fluid delivery pipe 3 can communicate with the chamber 100 of the corresponding layer. The elastic membrane 2 seals and surrounds the outer periphery of each cylinder 1a, and the through hole 11 is formed on the peripheral wall of the cylinder 1a. During the test, high-pressure fluid is input into the corresponding chamber 100 through the first high-pressure fluid delivery pipe 3, so that the high-pressure fluid enters the expansion space 20 through the hole 11 and forces the elastic membrane 2 to expand radially.

[0036] Optionally, multiple chambers 100 may share a single first high-pressure fluid delivery pipe 3, or each chamber 100 may have its own dedicated first high-pressure fluid delivery pipe 3. When sharing a single first high-pressure fluid delivery pipe 3, the first high-pressure fluid delivery pipe 3 is provided with a first inlet / outlet 31 corresponding to the position of each chamber 100, and a first valve (not shown) is provided at each first inlet / outlet 31 to control the opening and closing of the first inlet / outlet 31. When it is necessary to deliver high-pressure fluid to one or more chambers 100, the corresponding first valve is opened, while the other first valves remain closed. The first valve can be a manually operated valve or an electrically operated valve, preferably an electrically operated valve.

[0037] When each chamber 100 is equipped with a corresponding first high-pressure fluid delivery pipe 3, the outlet end of each first high-pressure fluid delivery pipe 3 extends downward to connect with the partition 10 of the corresponding chamber 100. It should be noted that the joint between the first high-pressure fluid delivery pipe 3 and the partition 10 should be sealed to prevent high-pressure fluid from leaking from the joint.

[0038] Optionally, to facilitate the connection of two vertically adjacent cylinders 1a, radially inwardly extending wing plates 1a-1 can be provided at the top of the cylinder 1a, and the wing plates 1a-1 of the two adjacent cylinders 1a can be fixed to the bottom plate by bolts or snap-fit ​​structures, or welded together. When using bolts or snap-fit ​​structures for connection, attention should be paid to waterproofing.

[0039] Preferably, the elastic membrane 2 is a tire-shaped annular structure, with the upper edge 21 and lower edge 22 of the elastic membrane extending radially inward and pressing and fixing it between the wing plate 1a-1 and the bottom plate, thereby sealing and surrounding the outer periphery of the cylinder 1a.

[0040] In this embodiment of the invention, the disturbance member 4 is generally corrugated cylindrical, with each section connected by folds. The front end of the disturbance member is closed, and the rear end is open and connected to the elastic membrane 2, with the connection sealed. The outlet end of the second high-pressure fluid delivery pipe 6 extends downward into the cavity 100 of the corresponding layer and is connected to the rear end of the disturbance member 4 through the high-pressure hose 61. The length of the high-pressure hose should meet the radial expansion and contraction requirements of the elastic membrane 2. The peripheral wall of the cylinder 1a is formed with a through hole 1a-2 for the high-pressure hose 61 to pass through. The inlet end (i.e., the upper end) of the second high-pressure fluid delivery pipe 6 is used to connect to an external high-pressure fluid source. The high-pressure fluid source inputs high-pressure fluid into the internal space of the disturbance member 4 through the second high-pressure fluid delivery pipe 6 and the high-pressure hose 61, which can drive the disturbance member 4 to expand in the radial direction of the pile body 1. When the fluid pressure applied to the disturbance member 4 is removed or the fluid pressure in the disturbance member 4 is extracted, the disturbance member 4 can contract under its own elastic force.

[0041] Optionally, the timing of introducing high-pressure fluid into the disturbance element 4 on the corresponding one or more layers of elastic membrane 2 can be carried out after the elastic membrane 2 has expanded radially to form a predetermined T-shaped, cross-shaped, or inverted T-shaped irregular pile shape, and before the test pile is buried in the test soil; or it can be carried out after the test pile is buried in the test soil.

[0042] Optionally, the disturbance element 4 is made of rigid plastic or metal sheet, and the front end is preferably made into a cone shape to facilitate insertion into the test soil. The rear end of the disturbance element 4 is preferably bonded and fixed to the elastic membrane 2 or integrally formed.

[0043] Specifically, the number of disturbance elements 4 on each layer of elastic membrane 2 is one or more. All disturbance elements 4 on the elastic membrane 2 can share a single second high-pressure fluid delivery pipe 6, or each disturbance element 4 on the elastic membrane 2 can have its own corresponding second high-pressure fluid delivery pipe 6. When sharing a single second high-pressure fluid delivery pipe 6, the second high-pressure fluid delivery pipe 6 is provided with a second inlet / outlet 60 corresponding to the position of each chamber 100, and a second valve (not shown) is provided at the second inlet / outlet 60 to control the opening and closing of the second inlet / outlet 60. When high-pressure fluid needs to be delivered to the disturbance elements 4 on one or more layers of elastic membrane 2, the corresponding second valve is opened, while the other second valves remain closed. The second valve can be a manually operated valve or an electrically operated valve, preferably an electrically operated valve.

[0044] In a preferred embodiment of the present invention, the grouting pipe 5 includes a radial grouting pipe 51 and an axial grouting pipe 52. The radial grouting pipe 51 is a flexible pipe that extends downward along the outer wall of the unexpanded elastic membrane 2 and is fixedly connected to the elastic membrane 2 (e.g., by binding or bonding), eventually extending to a position close to the outer wall of the expanded elastic membrane 2, with the grout outlet facing radially outward. Similarly, the radial grouting pipe 51 is fixedly connected to the expanded elastic membrane 2 to prevent the radial grouting pipe 51 from shifting relative to the elastic membrane 2. The axial grouting pipe 52 preferably extends downward from the inside of the pile body 1 to pass through the pile body 1, and the joint between the axial grouting pipe 52 and the partition 10 of the pile body 1 is sealed. During the experiment, high-pressure fluid is first introduced into one or more chambers 100 according to the test conditions and requirements, and the elastic membrane 2 of the corresponding layer is driven to expand radially to form a predetermined T-shaped, cross-shaped, or inverted T-shaped irregular pile shape. Then, the test pile is buried in the test soil in the existing way and the test soil is compacted from the top surface. Next, the test pile is driven to rotate by the drive mechanism to drive the disturbance component 4 to stir the surrounding soil, and grout is injected into the test soil through the radial grouting pipe 51. The surrounding soil is disturbed by the extended disturbance component, so that the grout can diffuse into the surrounding soil and make the grout and soil more closely integrated. Then, the fluid pressure applied to the expansion space 20 is reduced or removed, so that the elastic membrane 2 shrinks radially under the action of its own rebound force and the pressure difference inside and outside the expansion space, and forces the fluid in the expansion space 20 and the chamber 100 to flow out through the first high-pressure fluid delivery pipe 3. The gap between the elastic membrane 2 and the test soil after shrinkage is filled by grout. After the elastic membrane 2 has basically fully contracted, the test pile is slowly lifted and grouted through the axial grouting pipe 52, in conjunction with the grouting speed. This allows the grout to promptly fill the voids formed by the slow lifting of the test pile, until the test pile is completely detached from the test soil and the overall casting of the irregular pile is completed. In this embodiment, the number of radial grouting pipes 51 can be one or more, preferably two, with the two radial grouting pipes 51 radially symmetrically arranged on both sides of the pile body 1. Arranging the two radial grouting pipes 51 radially symmetrically on both sides of the pile body 1 can better ensure the uniformity of grout diffusion.

[0045] Understandably, when the interior and exterior of the uppermost cylinder 1a also need to form a chamber 100 and an expansion space 20 respectively, the top of the uppermost cylinder 1a is fixed (e.g., by bolts) with an upper cover plate 12 that seals and presses the upper edge 21 of the elastic membrane 2 tightly against the top of the uppermost cylinder 1a. Similarly, when the exterior of the lowermost cylinder 1 also needs to form a chamber 100 and an expansion space 20, the bottom wall of the lowermost cylinder 1a is fixed (e.g., by bolts) with a lower cover plate 13 that seals and presses the lower edge 22 of the elastic membrane 2 tightly against the bottom wall of the lowermost cylinder 1a.

[0046] After introducing the embodiments of the irregularly shaped mixing test pile of the present invention, the embodiments of the mixing test device having the above-mentioned irregularly shaped mixing test pile will be described next. The specific structure of the irregularly shaped mixing test pile is as described in the above embodiments, and repeated parts will not be described again.

[0047] like Figures 1-5 As shown, the mixing test device with the above-mentioned irregularly shaped mixing test pile includes a model box 7, a test pile, a high-pressure fluid source, a grouting device, and a drive mechanism.

[0048] The model box 7 is used to hold the test soil. The model box 7 is existing technology and well known to those skilled in the art. For example, it can adopt a square box structure with an open top. The specific structure will not be described in detail here, but attention should be paid to the waterproofness of the model box 7. The test pile is the test pile mentioned above. The specific structure is described in the above embodiment and will not be described in detail here. The high-pressure fluid source is connected to the inlet end of the first high-pressure fluid delivery pipe 3. It is used to input high-pressure fluid (such as high-pressure air or high-pressure water) into the target chamber 100 through the first high-pressure fluid delivery pipe 3, and to make the high-pressure fluid enter the expansion space 20 through the hole 11 to drive the elastic membrane 2 to expand radially to reach the required diameter, thereby locally expanding the diameter of the test pile to form a predetermined T-shaped, cross-shaped, or inverted T-shaped pile, etc. The grouting device is connected to the other end of the grouting pipe 5 and is used to grout the test soil through the grouting pipe 5. The driving mechanism is connected to the test pile and is used to drive the test pile to rise, fall, and rotate. The driving mechanism and the grouting device are existing technologies, and their specific structures and working principles will not be described in detail here.

[0049] During the experiment, high-pressure fluid is first introduced into one or more chambers 100 according to the experimental conditions and requirements, causing the elastic membrane 2 of the corresponding layer to expand radially, forming a predetermined T-shaped, cross-shaped, or inverted T-shaped irregular pile shape, thus meeting the needs of test piles with different shapes without the need to manufacture different irregular piles separately, which has good versatility and can save on the manufacturing cost of test piles; then, the test pile is placed in the test soil in the existing way and the test soil is compacted from the top surface; next, the test pile is driven to rotate by the drive mechanism to drive the disturbance component 4 to stir the surrounding soil and inject grout into the test soil. The disturbance component in the stretched state drives the surrounding soil to disturb, so that the grout can diffuse to the surrounding soil and make the grout and soil more closely integrated, thereby improving the reinforcement effect and increasing the treatment and reinforcement range of the test soil; then, the application is reduced or canceled. The fluid pressure applied within the expansion space 20 causes the elastic membrane 2 to contract radially under the action of the rebound force and the pressure difference between the inside and outside of the expansion space. This forces the fluid in the expansion space 20 and the chamber 100 to flow out through the first high-pressure fluid delivery pipe 3. The gap between the elastic membrane 2 and the test soil after contraction is filled with grout. After the elastic membrane 2 has basically completely contracted, the test pile is slowly lifted and grouting is maintained in conjunction with the grouting speed. This allows the grout to fill the voids formed by the slow lifting of the test pile in a timely manner until the test pile is completely removed from the test soil and the overall casting of the irregular pile is completed. Furthermore, since the test pile can support the test soil on its outer periphery during the lifting and grouting process, it can prevent the collapse of the pile and the severe deformation of the pile body. This improves the quality of the pile and the efficiency and effect of the test, thus providing a better reference or assistance for the treatment of soft soil foundations.

[0050] After introducing the embodiments of the irregular-shaped mixing test pile and the mixing test device using the above-mentioned irregular-shaped mixing test pile, the embodiments of the irregular-shaped mixing test method using the above-mentioned mixing test device will be introduced next. The specific structure of the irregular-shaped mixing test pile and the mixing test device using the above-mentioned irregular-shaped mixing test pile are as described in the above embodiments, and repeated parts will not be described again.

[0051] In the embodiments of the present invention, such as Figures 1 to 6 As shown, the irregular stirring test method includes the following steps:

[0052] S1. According to the test conditions and requirements, high-pressure fluid is introduced into the corresponding one or more chambers 100, and the elastic membrane 2 of the corresponding layer is driven to expand radially to reach the designed diameter, so that the test pile forms a predetermined irregular shape (such as T-shaped, cross-shaped or inverted T-shaped) to meet the requirements of test piles with different shapes, without the need to make different irregular piles separately. It has good versatility and can save the manufacturing cost of test piles.

[0053] Optionally, multiple chambers 100 may share a single first high-pressure fluid delivery pipe 3, or each chamber 100 may have its own dedicated first high-pressure fluid delivery pipe 3. When sharing a single first high-pressure fluid delivery pipe 3, the pipe has a first inlet / outlet 31 corresponding to each chamber 100, and a first valve at each inlet / outlet 31 to control its opening and closing. When high-pressure fluid needs to be delivered to one or more chambers 100, the corresponding first valve is opened, while the others remain closed. The high-pressure fluid enters the corresponding chamber 100 through the opened first valve, then enters the expansion space 20 through the inlet, ultimately driving the elastic membrane 2 to expand radially to the desired diameter. The first valve can be a manually operated valve or an electrically operated valve, preferably an electrically operated valve.

[0054] When each chamber 100 is equipped with a corresponding first high-pressure fluid delivery pipe 3, the outlet end of each first high-pressure fluid delivery pipe 3 extends downward to connect with the partition 10 of the corresponding chamber 100. It should be noted that the joint between the first high-pressure fluid delivery pipe 3 and the partition 10 should be sealed to prevent high-pressure fluid from leaking from the joint.

[0055] In addition, it should be noted that those skilled in the art can already know how the test pile should be assembled based on the description of the above-described test pile embodiments, and the specific assembly process of the test pile will not be described in detail here.

[0056] S2. Place the test pile in the test soil and compact it.

[0057] In this embodiment of the invention, the process of placing and compacting the test pile in the test soil is preferably carried out by first vertically placing the test pile in the model box 7 (Note: When the test pile is placed vertically in the model box 7, the inside of the model box 7 can be completely empty, or it can be filled with soil of a predetermined thickness that has been pre-filled and compacted), and then adding and compacting the test soil in layers. Specifically, the process of adding and compacting the test soil in layers into the model box 7 is as follows: each time, an appropriate thickness of test soil is filled, then the test soil is evenly spread out, and then compacted. After compaction, the upper surface is roughened to ensure close contact between the layers of test soil. It is preferable that the test soil 200 just covers the top of the test pile (such as the top surface of the upper cover plate 12).

[0058] In addition, it should be noted that the preparation of the test soil is a current technology and will not be elaborated here.

[0059] S3. Drive the test pile to rotate so that the disturbance element 4 mixes the surrounding soil and grouts the test soil. The surrounding soil is disturbed by the extended disturbance element, which allows the grout to spread to the surrounding soil and makes the grout and soil more closely integrated, thereby improving the reinforcement effect and increasing the treatment and reinforcement range of the test soil.

[0060] In a preferred embodiment of the present invention, the grouting pipe 5 includes a radial grouting pipe 51, which is a flexible pipe that extends downward along the outer wall of the unexpanded elastic membrane 2 and is fixedly connected to the elastic membrane 2 (e.g., by binding or bonding), eventually extending to a position close to the outer wall of the expanded elastic membrane 2, with the grout outlet facing radially outward. Similarly, the radial grouting pipe 51 is fixedly connected to the expanded elastic membrane 2 to prevent the radial grouting pipe 51 from shifting relative to the elastic membrane 2. The number of radial grouting pipes 51 can be one or more, preferably two. The two radial grouting pipes 51 are radially symmetrically arranged on both sides of the pile body 1. Arranging the two radial grouting pipes 51 radially symmetrically on both sides of the pile body 1 can better ensure the uniformity of grout diffusion.

[0061] Understandably, the rotation speed, grouting pressure, and grouting speed of the test pile are determined according to the test conditions (such as the hardness and moisture content of the test soil) and requirements, which will not be elaborated here.

[0062] S4. Reduce or remove the fluid pressure on the expansion space 20, so that the elastic membrane 2 contracts radially under the action of its own elasticity and slurry pressure.

[0063] Understandably, the radial shrinkage rate of the elastic membrane 2 can be determined by the grouting pressure, velocity, and the rate of change of fluid pressure in the expansion space 20. During the shrinkage process, the gap between the elastic membrane 2 and the test soil is filled with grout until the elastic membrane 2 completely shrinks.

[0064] S5. In conjunction with the grouting speed, the test pile is slowly lifted, and the grout is promptly used to fill the voids created by the slow lifting of the test pile, until the overall casting of the irregular pile is completed and the test pile is completely removed from the test soil. After a predetermined settling time (e.g., 28 days), the parameters of the treated test soil (such as strength) are studied and analyzed accordingly.

[0065] Because the test pile can support the test soil around the periphery during the lifting and grouting process, it can prevent the collapse of the pile and the deformation of the pile body, improve the quality of the pile, and enhance the efficiency and effectiveness of the test. This can better provide reference or assistance for the treatment of soft soil foundations.

[0066] In this embodiment of the invention, the grouting pipe 5 includes an axial grouting pipe 52, which preferably extends downward from the inside of the pile body 1 and passes through the pile body 1, and the joint between the axial grouting pipe 52 and the partition plate 10 of the pile body 1 is sealed. In step S5, the grout filling the cavity is completely or mainly introduced through the axial grouting pipe 52.

[0067] In this embodiment of the invention, the disturbance member 4 is generally corrugated cylindrical, with each section connected by folds. The front end of the disturbance member is closed, and the rear end is open and connected to the elastic membrane 2, with the connection sealed. The outlet end of the second high-pressure fluid delivery pipe 6 extends downward into the cavity 100 of the corresponding layer and is connected to the rear end of the disturbance member 4 through the high-pressure hose 61. The inlet end of the second high-pressure fluid delivery pipe 6 is used to connect to an external high-pressure fluid source (not shown). The high-pressure fluid source inputs high-pressure fluid into the internal space of the disturbance member 4 through the second high-pressure fluid delivery pipe 6 and the high-pressure hose 61, which can drive the disturbance member 4 to extend in the radial direction of the pile body 1. When the fluid pressure applied to the disturbance member 4 is removed or the fluid pressure in the disturbance member 4 is extracted, the disturbance member 4 can contract under its own elastic force.

[0068] Optionally, the timing of introducing high-pressure fluid into the disturbance element 4 on the corresponding one or more layers of elastic membrane 2 can be after the elastic membrane 2 has expanded radially to form a predetermined T-shaped, cross-shaped, or inverted T-shaped irregular pile shape, and before the test pile is buried in the test soil. That is, step S1 also includes the process of introducing high-pressure fluid into the internal space of the disturbance element 4 to cause the disturbance element 4 to extend in the radial direction of the pile body 1.

[0069] Of course, the timing for introducing high-pressure fluid into the disturbance element 4 on the corresponding one or more layers of elastic membrane 2 can also be carried out after the test pile is buried in the test soil.

[0070] It should be noted that, if testing is required, pore water pressure sensors (not shown) and earth pressure cells (not shown) can be pre-embedded in the test soil to monitor changes in pore pressure and stress during the test. After the test, the changes in pore pressure and stress data obtained from the test can be studied and analyzed to provide corresponding references or assistance for actual soft soil foundation mixing pile treatment. Specific methods for research and analysis will not be elaborated here; however, existing research and analysis methods can be referenced.

[0071] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A specially shaped test pile, characterized in that, include: The pile body is hollow inside, and multiple partitions are axially spaced inside the hollow body to divide the internal space of the pile body into multiple independent chambers. An elastic membrane is fixed to the outer periphery of the pile body and seals and surrounds the area of ​​each cavity on the outer periphery of the pile body, forming a multi-layer controllable expansion space. The peripheral wall of the pile body is also formed with through holes that connect the corresponding cavities and expansion spaces. The first high-pressure fluid delivery pipe has an outlet end connected to the chamber and an inlet end connected to an external high-pressure fluid source. Multiple disturbance elements are provided on the outside of the elastic membrane. They can extend and squeeze into the test soil in the radial direction of the pile. When the pile rotates under the drive of the external drive mechanism, the disturbance elements can rotate with the pile and stir the surrounding soil. as well as The grouting pipe has one end extending to the outside of the pile body and / or elastic membrane, and the other end can be connected to an external grouting device for grouting the test soil.

2. A shaped mixing test pile according to claim 1, wherein: The pile body includes a plurality of vertically stacked and fixedly connected open-top cylinders, with vertically adjacent cylinders fixedly connected to each other. The bottom plate of the cylinder forms the partition and divides the internal space of the two vertically adjacent cylinders to form multiple layers of the chambers. An elastic membrane seals and surrounds the outer periphery of each cylinder.

3. A shaped mixing test pile according to claim 2, wherein: The top of the cylinder is provided with radially inward extending wing plates, and the wing plates of two adjacent cylinders are fixed to the bottom plate by bolts or snap-fit ​​structures, or by welding.

4. A shaped mixing test pile according to claim 3, wherein: The elastic membrane has a tire-shaped annular structure. The upper and lower edges of the elastic membrane extend radially inward and are pressed and fixed between the wing and the bottom plate, sealing and surrounding the outer periphery of the cylinder.

5. The specialty mixing test pile of claim 1, wherein: The disturbance component is generally corrugated cylindrical, with each section connected by folds. The front end of the disturbance component is closed, and the rear end is open and connected to the elastic membrane. The connection is sealed. The outlet end of the second high-pressure fluid delivery pipe extends downward into the cavity of the corresponding layer and is connected to the rear end of the disturbance component through a high-pressure hose. The inlet end of the second high-pressure fluid delivery pipe is used to connect to an external high-pressure fluid source.

6. The specialty mixing test pile of claim 1, wherein: The grouting pipe includes radial grouting pipe and axial grouting pipe. The radial grouting pipe is a flexible pipe that extends downward along the outer wall of the unexpanded elastic membrane and is fixed to the elastic membrane, eventually extending to a position close to the outer wall of the expanded elastic membrane, with the grout outlet facing radially outward. The axial grouting pipe extends downward from the inside of the pile body to pass through the pile body.

7. A shaped mixing test pile according to claim 4, wherein: The top of the uppermost cylinder is fixedly connected to an upper cover plate that seals and presses the upper edge of the elastic membrane tightly against the top of the uppermost cylinder; the bottom wall of the lowermost cylinder is fixedly connected to a lower cover plate that seals and presses the lower edge of the elastic membrane tightly against the bottom wall of the lowermost cylinder.

8. A heteromorphic stirring test device, characterized by The device includes a model box, a high-pressure fluid source, a grouting device, a drive mechanism, and a test pile as described in any one of claims 1 to 7. The model box is used to hold the test soil. The high-pressure fluid source is connected to the inlet end of the first high-pressure fluid delivery pipe. The grouting device is connected to the other end of the grouting pipe. The drive mechanism is connected to the test pile and is used to drive the test pile to rise, fall, and rotate.

9. A stirring test method using the irregular shaped stirring test device according to claim 8, characterized by, Includes the following steps: S1. According to the test conditions and requirements, high-pressure fluid is introduced into the corresponding one or more chambers, and the elastic membrane of the corresponding layer is driven to expand radially. S2. Place the test pile in the test soil and compact it; S3. Drive the test pile to rotate so that the disturbance component mixes the surrounding soil and grouts the test soil. S4. Reduce or remove the fluid pressure on the expansion space, causing the elastic membrane to contract radially; S5. Combine the grouting speed with the slow lifting of the test pile until the overall pouring of the irregular pile is completed and the test pile is completely separated from the test soil.

10. The stirred test method of claim 9, wherein: Step S1 also includes the process of introducing high-pressure fluid into the internal space of the disturbance component to cause the disturbance component to stretch in the radial direction of the pile body.

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