Improved sleeve valve pipe grouting experimental device and experimental method

Abstract

The invention relates to the technical field of impact mechanics and engineering grouting, in particular to an improved sleeve valve pipe grouting experimental device and experimental method. The experimental device is buried in a soil body and comprises a grouting pipe, an annular inner layer sleeve shell assembly, an annular outer layer sleeve shell assembly, a first sealing part and a second sealing part. The annular inner layer sleeve shell assembly and the annular outer layer sleeve shell assembly are sequentially and coaxially arranged on the outer side of the grouting pipe. The annular inner-layer sleeve shell assembly and the annular outer-layer sleeve shell assembly are made of brittle materials, and the brittle strength of the annular inner-layer sleeve shell assembly is higher than that of the annular outer-layer sleeve shell assembly; a sealed pressure chamber is defined by the first sealing part, the second sealing part, the grouting pipe and the annular inner layer sleeve shell assembly; and a plurality of groups of grouting ports are annularly formed in the pipe section, positioned in the sealed pressure chamber, of the grouting pipe. According to the experimental method, the experimental device is adopted to realize continuous and uniform ring opening of the grout stopping ring, so that grout is uniformly diffused to a soil body to reinforce a soil layer, and the first fragments and the second fragments carried by the grout extrude the soil body to improve the bearing capacity of the soil body.

Description

Technical Field

[0001] The present invention relates to the technical fields of impact mechanics and engineering grouting technology, and particularly relates to an improved sleeve valve pipe grouting experimental device and an experimental method. Background Art

[0002] The valve pipe pre-grouting reinforcement method is being applied to more complex shield geological environments due to its reliable grouting reinforcement effect and good induced splitting grouting control effect. Among them, the application of the sleeve valve pipe pre-grouting technology can effectively control the ground settlement and prevent local uplift and excessive inclination. However, during the deep-buried grouting construction process of the sleeve valve pipe, there are problems that the casing material grouting stop ring is prone to local failure (i.e., the grouting stop ring does not open locally) or uneven opening during the opening process, resulting in uneven grouting, and then uneven reinforcement of the soil layer, seriously affecting the actual effect of the grouting project.

[0003] In order to optimize the opening efficiency of the grouting stop ring of the sleeve valve pipe and improve the grouting uniformity, it is usually necessary to carry out grouting effect tests. At present, the failure problems of the casing material grouting stop ring are mostly studied by expanding the uniform stress and non-uniform stress force models of the traditional circular sleeve under the action of in-situ stress. Further, an improved sleeve valve pipe grouting site test study with coarse sand as the casing material is carried out. The response of acceleration and earth pressure during the grouting process is tested, and the soil layer around the sleeve valve pipe after grouting is excavated and analyzed to evaluate the grouting reinforcement effect of the improved casing material sleeve valve pipe. A theoretical calculation method for the opening pressure of the sleeve valve pipe considering the comprehensive influence of multiple factors is established in combination with the field test, and the influence laws of the material strength of the grouting stop ring and the elastic modulus of the grouting stop ring material and the grouting soil on the opening pressure are deeply studied. However, the grouting project is a concealed project, and there are deficiencies in the research on local grouting caused by the opening failure of the grouting stop ring.

[0004] In summary, the existing sleeve valve pipe grouting structure will greatly affect the construction efficiency and effect of the grouting project due to defects such as grouting burial depth and construction process. And the high-efficiency and stable opening efficiency of the sleeve valve pipe and the uniformity of the grout veins are very important for the grouting structure. Therefore, it is necessary to design and develop an improved sleeve valve pipe grouting experimental device and an experimental method to solve the problems that the casing material grouting stop ring appears local failure or uneven opening during the opening process due to defects in the existing sleeve valve pipe grouting structure and construction process. Summary of the Invention

[0005] The purpose of the present invention is to provide an improved sleeve valve pipe grouting experimental device and an experimental method, and the specific technical solutions are as follows: In a first aspect, the present invention provides an improved sleeve valve pipe grouting experimental device buried in soil, which includes a grouting pipe, an inner circumferential layer sleeve assembly, an outer circumferential layer sleeve assembly, a first sealing component, and a second sealing component; the inner circumferential layer sleeve assembly is coaxially arranged outside the grouting pipe, and a circumferential gap is provided between the two; the first sealing component and the second sealing component are respectively arranged at the two axial ends of the circumferential gap; a sealed pressure chamber is formed by the first sealing component, the second sealing component, the grouting pipe, and the inner circumferential layer sleeve assembly; multiple groups of grouting ports are circumferentially arranged on the pipe section of the grouting pipe located inside the sealed pressure chamber; the pipe orifice of the grouting pipe located outside the sealed pressure chamber is connected to an external grouting device; the outer circumferential layer sleeve assembly is coaxially arranged outside the inner circumferential layer sleeve assembly, its inner wall is in contact with the outer wall of the inner circumferential layer sleeve assembly, and the outer wall is in contact with the soil; the materials of the inner circumferential layer sleeve assembly and the outer circumferential layer sleeve assembly are both brittle materials, and the brittle strength of the latter is higher than that of the former.

[0006] Optionally, the inner circumferential layer sleeve assembly includes an inner circumferential layer sleeve housing and a first filling layer arranged in the inner circumferential layer sleeve housing; the material of the inner circumferential layer sleeve housing is a brittle material; the filling material of the first filling layer includes gravel particles, ceramic particles, and glass particles.

[0007] Optionally, the size of the gravel particles is 1-20 mm; the size of the ceramic particles is 1-20 mm; the size of the glass particles is 1-20 mm.

[0008] Optionally, the outer circumferential layer sleeve assembly includes an outer circumferential layer sleeve housing and a second filling layer arranged in the outer circumferential layer sleeve housing; the materials of the outer circumferential layer sleeve housing and the second filling layer are both bentonite.

[0009] Optionally, the number of the first sealing components includes one or more; when the number of the first sealing components is multiple, each of the first sealing components is sequentially stacked on one axial end of the circumferential gap.

[0010] Optionally, the number of the second sealing components includes one or more; when the number of the second sealing components is multiple, each of the second sealing components is sequentially stacked on the other axial end of the circumferential gap.

[0011] Optionally, each group of the grouting ports includes multiple grouting ports arranged along the axial direction of the grouting pipe; the aperture of the grouting port is 3-4 cm.

[0012] In a second aspect, the present invention provides an experimental method using the improved sleeve valve pipe grouting experimental device, including: Step S1: Use an external grouting device to inject grout into the grouting pipe under pressure. The grout fills the sealed pressure chamber in a sputtering manner through the grouting orifice. At the same time, the grout flowing into the sealed pressure chamber has kinetic energy, which can continuously impact the inner circumferential layer casing assembly, forcing the inner circumferential layer casing assembly to crack and break, forming multiple first fragments. Step S2: Continue to use an external grouting device to inject grout into the grouting pipe under pressure. The grout carries the first fragments and continuously impacts and collides with the outer circumferential layer casing assembly until the outer circumferential layer casing assembly cracks and breaks, forming multiple second fragments. Subsequently, the grout uniformly diffuses into the soil to reinforce the soil layer, and the first fragments and the second fragments carried by the grout squeeze the soil to improve the soil bearing capacity.

[0013] Optionally, the pressure for the pressure grouting is 0.6 - 2.0 MPa.

[0014] Optionally, the volume of the sealed pressure chamber is a variable volume, and its size is determined by the difference between the inner diameter of the inner circumferential layer casing assembly and the outer diameter of the grouting pipe.

[0015] Applying the technical solution of the present invention has at least the following beneficial effects: An improved sleeve valve pipe grouting experimental device and experimental method provided by the present invention can solve the problems of local failure (i.e., local non-opening of the grout stop ring) or non-uniform opening of the grout stop ring during the opening process of the existing sleeve valve pipe grouting structure and construction process defects. Specifically, the grout stop ring adopted by the present invention includes an inner circumferential layer casing assembly and an outer circumferential layer casing assembly. The materials of the inner circumferential layer casing assembly and the outer circumferential layer casing assembly are both brittle materials, and the brittleness strength of the latter is higher than that of the former, which is convenient for subsequent gradual fragmentation by the grout with kinetic energy to achieve continuous and uniform opening of the grout stop ring. Further, the present application uses an external grouting device to inject grout into the grouting pipe under pressure. The grout uniformly fills the sealed pressure chamber in a sputtering manner through a plurality of circumferential grouting orifices. At the same time, the grout flowing into the sealed pressure chamber has kinetic energy, which can continuously impact the inner circumferential layer casing assembly, forcing the inner circumferential layer casing assembly to crack and break, forming multiple first fragments. Continue to use an external grouting device to inject grout into the grouting pipe under pressure. The grout carries the first fragments and continuously impacts and collides with the outer circumferential layer casing assembly until the outer circumferential layer casing assembly cracks and breaks, forming multiple second fragments. Subsequently, the grout uniformly diffuses into the soil to reinforce the soil layer, and the first fragments and the second fragments carried by the grout squeeze the soil to improve the soil bearing capacity. The experimental method protected by the present invention has simple steps, is easy to operate and has strong practicability.

[0016] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is a perspective structural view of an improved sleeve valve pipe grouting experimental device in an embodiment; Figure 2 is a top view of an improved sleeve valve pipe grouting experimental device in an embodiment; Figure 3 is a top view of an improved sleeve valve pipe grouting experimental device when the inner circumferential layer sleeve component is opened in an embodiment; Figure 4 is a top view of an improved sleeve valve pipe grouting experimental device when the outer circumferential layer sleeve component is opened in an embodiment; Figure 5 is a top view of an improved sleeve valve pipe grouting experimental device after being completely opened in an embodiment; Among them, 1. Grouting pipe, 1.1 Grouting port, 2 Inner circumferential layer sleeve component, 3 Outer circumferential layer sleeve component, 4 First sealing component, 5 Second sealing component, 6 Sealing pressure chamber, 7 Inner layer impact loss boundary, 8 Outer layer impact loss boundary, 9 Soil impact loss boundary, W Soil; In Figures 1-5 the arrows and directions acting on the soil are the soil layer stresses and directions received by the soil. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention. Embodiment:

[0019] See Figures 1-5, An improved sleeve valve pipe grouting experimental device is buried in soil mass W, and includes a grouting pipe 1, an inner circumferential outer sleeve assembly 2, an outer circumferential outer sleeve assembly 3, a first sealing member 4 and a second sealing member 5; the inner circumferential outer sleeve assembly 2 is coaxially arranged outside the grouting pipe 1, and a circumferential gap is provided between the two; the first sealing member 4 and the second sealing member 5 are respectively arranged at the two axial ends of the circumferential gap; a sealed pressure chamber 6 is formed by the first sealing member 4, the second sealing member 5, the grouting pipe 1 and the inner circumferential outer sleeve assembly 2; a plurality of groups of grouting ports 1.1 are circumferentially arranged on the pipe section of the grouting pipe 1 located inside the sealed pressure chamber 6; the pipe opening of the grouting pipe 1 located outside the sealed pressure chamber 6 is connected to an external grouting device (not shown in the figure); the outer circumferential outer sleeve assembly 3 is coaxially arranged outside the inner circumferential outer sleeve assembly 2, its inner wall is in contact with the outer wall of the inner circumferential outer sleeve assembly 2, and the outer wall is in contact with the soil mass W; the materials of the inner circumferential outer sleeve assembly 2 and the outer circumferential outer sleeve assembly 3 are both brittle materials, and the brittle strength of the latter is higher than that of the former.

[0020] The inner circumferential outer sleeve assembly 2 includes an inner circumferential outer sleeve housing (with a thickness of 2 - 3 cm, specifically selected as 2 cm; the material is bentonite; the brittle strength is 0.4 - 0.5 MPa, specifically selected as 0.4 MPa) and a first filling layer arranged inside the inner circumferential outer sleeve housing; the material used for the inner circumferential outer sleeve housing is a brittle material; the filling material used for the first filling layer includes gravel particles, ceramic particles and glass particles (preferably gravel particles, and the particle size is 10 - 15 mm). When the slurry impacts and collides with the outer circumferential outer sleeve assembly 3, this filling material can not only accelerate the kinetic energy of the slurry, but also serve as an impact carrier to increase the impact strength and promote the continuous and uniform opening of the outer circumferential outer sleeve assembly 3.

[0021] The outer circumferential outer sleeve assembly 3 includes an outer circumferential outer sleeve housing (with a thickness of 3 - 5 cm, specifically selected as 4 cm; the brittle strength is 0.6 - 0.8 MPa, specifically selected as 0.7 MPa) and a second filling layer arranged inside the outer circumferential outer sleeve housing; the materials used for the outer circumferential outer sleeve housing and the second filling layer are both bentonite, which has good brittle strength on the one hand, and on the other hand, when the impact strength reaches the limit value, it can be continuously and uniformly opened.

[0022] The number of the first sealing members 4 (specifically sealing rings) is two, and each of the first sealing members 4 is sequentially stacked on one axial end of the circumferential gap.

[0023] The number of the second sealing members 5 (specifically sealing rings) is two, and each of the second sealing members 5 is sequentially stacked on the other axial end of the circumferential gap.

[0024] Each of the grouting ports 1.1 includes a plurality of grouting ports 1.1 arranged axially along the grouting pipe 1; the aperture of the grouting port 1.1 is 3 cm.

[0025] See Figures 1-5 , an experimental method using the improved sleeve valve pipe grouting experimental device as described above, including: Step S1: Use an external grouting device to inject grout into the grouting pipe 1 under pressure (the applied pressure is 1 MPa). The grout fills the sealed pressure chamber 6 in a sputtering manner through the grouting port 1.1. At the same time, the grout flowing into the sealed pressure chamber 6 has kinetic energy, which comes from the kinetic energy provided by the pressure grouting method. The grout flowing into the sealed pressure chamber 6 cannot flow axially along the sealed pressure chamber 6 and can only impact in the radial direction inside the sealed pressure chamber 6, thereby continuously impacting the inner ring sleeve assembly 2, forcing the inner ring sleeve assembly 2 to crack and break, forming a plurality of first fragments. During this process, the impact boundary formed on the inner ring sleeve assembly 2 is defined as the inner impact loss boundary 7 (between the inner wall and the outer wall of the inner ring sleeve assembly 2). As the grout pressure in the sealed pressure chamber 6 continuously increases and the first fragments continuously impact, the inner ring sleeve assembly 2 is uniformly damaged, and the inner impact loss boundary 7 coincides with the inner wall of the outer ring sleeve assembly 3. The volume of the sealed pressure chamber 6 increases, and the impact energy of the grout is further consumed. Therefore, it is necessary to re-accumulate kinetic energy. Step S2: Continue to use an external grouting device to inject grout into the grouting pipe 1 under pressure (the applied pressure is 1.2 MPa). The grout carries the first fragments and continuously impacts and collides with the outer ring sleeve assembly 3 until the outer ring sleeve assembly 3 cracks and breaks, forming a plurality of second fragments. During this process, the impact boundary formed on the outer ring sleeve assembly 3 is defined as the outer impact loss boundary 8 (between the inner wall and the outer wall of the outer ring sleeve assembly 3). The grout in the sealed pressure chamber 6, as well as the first and second fragments carried by the grout, continuously squeeze and collide with the outer ring sleeve assembly 3 along the outer impact loss boundary 8 in the normal direction of the soil body W until the outer ring sleeve assembly 3 is continuously and evenly opened. Subsequently, the grout uniformly diffuses and extends into the soil body to the soil impact loss boundary 9 (in the soil body W), strengthening the soil layer. The grout continuously diffuses into the soil body W, and the first and second fragments carried by the grout form uniform open-loop grout veins under the drive of instantaneous kinetic energy, squeezing and lifting the bearing capacity of the soil body W.

[0026] The volume of the sealed pressure chamber 6 is a variable volume, and its size is determined by the difference between the inner diameter of the inner ring sleeve assembly 2 and the outer diameter of the grouting pipe 1. If it is necessary to increase the kinetic energy of the slurry in the sealed pressure chamber 6, the volume of the sealed pressure chamber 6 is increased, so that the amount of slurry therein increases, and the accumulated kinetic energy increases, generating a stronger crushing impact force on the grout stop ring (i.e., the inner ring sleeve assembly 2 and the outer ring sleeve assembly 3).

[0027] The grouting pipe 1 used in the improved sleeve valve pipe grouting experimental device is buried in the soil mass W and can continuously perform multiple groutings. Through the impact and destruction of the slurry, the grout stop ring is continuously and evenly opened, so as to effectively control the slurry flow direction and achieve uniform slurry diffusion, reinforce the soil layer, ensure the success of the grouting construction and the long-term stability of the soil mass W, and prevent problems such as local non-opening or uneven opening of the grout stop ring.

[0028] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An improved sleeve valve pipe grouting experimental device, buried in soil (W), characterized in that: The invention comprises a grouting pipe (1), an annular inner shell assembly (2), an annular outer shell assembly (3), a first sealing component (4) and a second sealing component (5); the annular inner shell assembly (2) is coaxially arranged on the outer side of the grouting pipe (1), and an annular gap is arranged between the two; the first sealing component (4) and the second sealing component (5) are respectively arranged at the axial ends of the annular gap; the first sealing component (4), the second sealing component (5), the grouting pipe (1) and the annular inner shell assembly (2) form a sealed pressure chamber (6); A plurality of groups of grouting ports (1.1) are circumferentially arranged on the pipe section of the grouting pipe (1) located inside the sealed pressure chamber (6); the pipe port on the grouting pipe (1) located outside the sealed pressure chamber (6) is connected to external grouting equipment; the annular outer shell component (3) is coaxially arranged on the outside of the annular inner shell component (2), and its inner wall is arranged to fit the outer wall of the annular inner shell component (2), while the outer wall is in contact with the soil (W); the materials of the annular inner shell component (2) and the annular outer shell component (3) are both brittle materials, and the brittle strength of the latter is higher than that of the former.

2. The improved sleeve valve pipe grouting experimental device according to claim 1 is characterized in that: The annular inner shell assembly (2) comprises an annular inner shell shell and a first filling layer arranged in the annular inner shell shell; the material used in the annular inner shell shell is a brittle material; and the filling material used in the first filling layer comprises crushed stone particles, ceramic particles and glass particles.

3. The improved sleeve valve pipe grouting experimental device according to claim 2 is characterized in that: The size of the crushed stone particles is 1-20 mm; the size of the ceramic particles is 1-20 mm; the size of the glass particles is 1-20 mm.

4. The improved sleeve valve pipe grouting experimental device according to claim 1 is characterized in that: The annular outer shell assembly (3) comprises an annular outer shell shell and a second filling layer arranged inside the annular outer shell shell; the materials used for the annular outer shell shell and the second filling layer are both bentonite.

5. The improved sleeve valve pipe grouting experimental device according to claim 1 is characterized in that: The number of the first sealing components (4) ranges from one to more than one; when the number of the first sealing components (4) is more than one, each of the first sealing components (4) is sequentially stacked and arranged at one axial end of the annular gap.

6. The improved sleeve valve pipe grouting experimental device according to claim 1 is characterized in that: The number of the second sealing components (5) ranges from one to more than one. When the number of the second sealing components (5) is more than one, each of the second sealing components (5) is sequentially stacked and arranged at the other end of the annular gap in the axial direction.

7. The improved sleeve valve pipe grouting experimental device according to claim 1 is characterized in that: Each group of the grouting ports (1.1) comprises a plurality of grouting ports (1.1) arranged along the axial direction of the grouting pipe (1); the aperture of the grouting ports (1.1) is 3-4 cm.

8. An experimental method using the improved sleeve valve tube grouting experimental device as described in any one of claims 1 to 7, characterized in that: include: Step S1, using external grouting equipment to pressurize and inject grout into the grouting pipe (1), so that the grouting liquid fills the sealed pressure chamber (6) in a sputtering manner through the grouting port (1.1); at the same time, the grouting liquid flowing into the sealed pressure chamber (6) has kinetic energy and can continuously impact the annular inner shell component (2), forcing the annular inner shell component (2) to crack and break, thereby forming a plurality of first fragments; Step S2, continue to use external grouting equipment to pressurize and grout the grouting pipe (1), the slurry carries the first fragment and continuously impacts and collides with the annular outer shell component (3) until the annular outer shell component (3) is cracked and broken, forming a plurality of second fragments; then, the slurry is evenly diffused into the soil (W) to reinforce the soil layer, and the first fragment and the second fragment carried by the slurry are squeezed into the soil (W) to increase the bearing capacity of the soil (W).

9. The experimental method according to claim 8, characterized in that: The pressure used in the pressure grouting is 0.6-2.0MPa.

10. The experimental method according to claim 8, characterized in that: The volume of the sealed pressure chamber (6) is a variable volume, and its size is determined by the difference between the inner diameter of the annular inner shell assembly (2) and the outer diameter of the grouting pipe (1).

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