An improved sleeve valve pipe grouting experimental device and experimental method

Abstract

The present invention relates to the technical fields of impact mechanics and engineering grouting, and particularly relates to an improved sleeve valve pipe grouting experimental device and an experimental method. The experimental device is buried in soil, and 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 and the outer circumferential layer sleeve assembly are coaxially arranged on the outside of the grouting pipe in sequence; 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; 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; a plurality of groups of grouting ports are circumferentially arranged on the pipe section of the grouting pipe located in the sealed pressure chamber. The experimental method uses the experimental device to realize continuous and uniform opening of the grouting stop ring, enabling the grout to uniformly diffuse into the soil, reinforce the soil layer, and the first fragments and the second fragments carried by the grout to squeeze the soil to improve the bearing capacity of the soil.

Description

Technical Field

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

[0002] The pre-grouting reinforcement method of the valve pipe is being applied to more complex shield geological environments due to its reliable grouting reinforcement effect and good control effect on induced fracture grouting. 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 construction process of deep-buried grouting of the sleeve valve pipe, there are problems that the casing material slurry stop ring is prone to local failure (i.e., the slurry 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 sleeve valve pipe slurry stop ring and improve the grouting uniformity, it is usually necessary to carry out grouting effect tests. At present, the failure problem of the casing material slurry stop ring is 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 law of the material strength of the slurry stop ring and the elastic modulus of the slurry stop ring material and the grouted soil on the opening pressure is 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 slurry 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. 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 slurry stop ring of the existing sleeve valve pipe grouting structure and construction process defects cause local failure or uneven opening during the opening 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:

[0006] 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 outer sleeve assembly, an outer circumferential outer sleeve assembly, a first sealing member, and a second sealing member; the inner circumferential outer sleeve assembly is coaxially arranged outside the grouting pipe, and an annular gap is provided between the two; the first sealing member and the second sealing member are respectively arranged at the two axial ends of the annular gap; a sealed pressure chamber is formed by the first sealing member, the second sealing member, the grouting pipe, and the inner circumferential outer 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 outer sleeve assembly is coaxially arranged outside the inner circumferential outer sleeve assembly, its inner wall is attached to the outer wall of the inner circumferential outer sleeve assembly, and the outer wall is in contact with the soil; the materials of the inner circumferential outer sleeve assembly and the outer circumferential outer sleeve assembly are both brittle materials, and the brittle strength of the latter is higher than that of the former.

[0007] Optionally, the inner circumferential outer sleeve assembly includes an inner circumferential outer sleeve housing 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 crushed stone particles, ceramic particles, and glass particles.

[0008] Optionally, 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.

[0009] Optionally, the outer circumferential outer sleeve assembly includes an outer circumferential outer sleeve housing 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.

[0010] Optionally, the number of the first sealing members includes one or more; when the number of the first sealing members is multiple, each of the first sealing members is sequentially stacked on one axial end of the annular gap.

[0011] Optionally, the number of the second sealing members includes one or more; when the number of the second sealing members is multiple, each of the second sealing members is sequentially stacked on the other axial end of the annular gap.

[0012] 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.

[0013] In a second aspect, the present invention provides an experimental method using the improved sleeve valve pipe grouting experimental device, including:

[0014] 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 sleeve assembly, forcing the inner circumferential layer sleeve assembly to crack and break, forming multiple first fragments.

[0015] 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 sleeve assembly until the outer circumferential layer sleeve assembly cracks and breaks, forming multiple second fragments. Subsequently, the grout diffuses evenly 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.

[0016] Optionally, the pressure for the pressure grouting is 0.6 - 2.0 MPa.

[0017] 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 sleeve assembly and the outer diameter of the grouting pipe.

[0018] Applying the technical solution of the present invention has at least the following beneficial effects:

[0019] 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., partial non-opening of the grout stop ring) or uneven 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 sleeve assembly and an outer circumferential layer sleeve assembly. 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, 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 evenly 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 sleeve assembly, forcing the inner circumferential layer sleeve 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 sleeve assembly until the outer circumferential layer sleeve assembly cracks and breaks, forming multiple second fragments. Subsequently, the grout diffuses evenly 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.

[0020] 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

[0021] 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 of the present invention. In the drawings:

[0022] Figure 1 is a perspective structural view of an improved sleeve valve pipe grouting experimental device in an embodiment;

[0023] Figure 2 is a top view of an improved sleeve valve pipe grouting experimental device in an embodiment;

[0024] Figure 3 is a top view of an improved sleeve valve pipe grouting experimental device when the inner circumferential layer sleeve assembly is opened in an embodiment;

[0025] Figure 4 is a top view of an improved sleeve valve pipe grouting experimental device when the outer circumferential layer sleeve assembly is opened in an embodiment;

[0026] Figure 5 is a top view of an improved sleeve valve pipe grouting experimental device after being completely opened in an embodiment;

[0027] Among them, 1, grouting pipe, 1.1, grouting port, 2, inner circumferential layer sleeve assembly, 3, outer circumferential layer sleeve assembly, 4, first sealing member, 5, second sealing member, 6, sealing pressure chamber, 7, inner layer impact loss boundary, 8, outer layer impact loss boundary, 9, soil impact loss boundary, W, soil;

[0028] In Figures 1 - 5 the arrow and direction acting on the soil are the soil layer stress and direction received by the soil. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] 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.

[0030] Embodiment:

[0031] See Figures 1 - 5, an improved sleeve valve pipe grouting experimental device, buried in soil mass W, comprising a grouting pipe 1, an inner circumferential outer sleeve component 2, an outer circumferential outer sleeve component 3, a first sealing component 4 and a second sealing component 5; the inner circumferential outer sleeve component 2 is coaxially arranged outside the grouting pipe 1, and a circumferential gap is arranged between the two; the first sealing component 4 and the second sealing component 5 are respectively arranged at the two axial ends of the circumferential gap; a sealed pressure chamber 6 is formed by the first sealing component 4, the second sealing component 5, the grouting pipe 1 and the inner circumferential outer sleeve component 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 orifice 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 component 3 is coaxially arranged outside the inner circumferential outer sleeve component 2, its inner wall is in contact with the outer wall of the inner circumferential outer sleeve component 2, and its outer wall is in contact with the soil mass W; the materials of the inner circumferential outer sleeve component 2 and the outer circumferential outer sleeve component 3 are both brittle materials, and the brittle strength of the latter is higher than that of the former.

[0032] The inner circumferential outer sleeve component 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, with a particle size of 10 - 15 mm), and this filling material can not only accelerate the kinetic energy of the slurry when the slurry impacts and collides with the outer circumferential outer sleeve component 3, 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 component 3.

[0033] The outer circumferential outer sleeve component 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, can be continuously and uniformly opened when the impact strength reaches the limit value.

[0034] The number of the first sealing components 4 (specifically sealing rings) is two, and each of the first sealing components 4 is sequentially stacked on one axial end of the circumferential gap.

[0035] The number of the second sealing components 5 (specifically sealing rings) is two, and each of the second sealing components 5 is sequentially stacked on the other axial end of the circumferential gap.

[0036] Each of the grouting ports 1.1 includes a plurality of grouting ports 1.1 arranged along the axial direction of the grouting pipe 1; the aperture of the grouting port 1.1 is 3 cm.

[0037] See Figures 1 - 5 , an experimental method using the improved sleeve valve pipe grouting experimental device as described above, includes:

[0038] Step S1: Use an external grouting device to pressurize and grout into the grouting pipe 1 (the applied pressure is 1 MPa), and the slurry fills the sealed pressure chamber 6 in a sputtering manner through the grouting port 1.1; at the same time, the slurry flowing into the sealed pressure chamber 6 has kinetic energy, which comes from the kinetic energy provided by the pressurized grouting method. The slurry flowing into the sealed pressure chamber 6 cannot flow along the axial direction of the sealed pressure chamber 6 and can only impact in the radial direction within 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 slurry 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 slurry is further consumed. Therefore, it is necessary to re-accumulate kinetic energy;

[0039] Step S2: Continue to use an external grouting device to pressurize and grout into the grouting pipe 1 (the applied pressure is 1.2 MPa), and the slurry 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 slurry in the sealed pressure chamber 6 and the first and second fragments carried by the slurry 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 slurry uniformly diffuses and extends into the soil body impact loss boundary 9 (in the soil body W) to reinforce the soil layer. The slurry continuously diffuses into the soil body W, and the first and second fragments carried by the slurry form a uniform open-loop grout vein under the drive of instantaneous kinetic energy to squeeze and lift the bearing capacity of the soil body W.

[0040] The volume of the sealed pressure chamber 6 is a variable volume, the size of which 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 impact force for breaking the grout stop ring (i.e., the inner ring sleeve assembly 2 and the outer ring sleeve assembly 3).

[0041] 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 grouting multiple times. 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 realize the uniform diffusion of the slurry, 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 partial non-opening or uneven opening of the grout stop ring.

[0042] 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 is buried in the soil mass (W), and is characterized in that, It includes a grouting pipe (1), an inner circumferential sleeve assembly (2), an outer circumferential sleeve assembly (3), a first sealing member (4) and a second sealing member (5); the inner circumferential sleeve assembly (2) is coaxially arranged outside the grouting pipe (1), and a circumferential gap is arranged 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 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; the outer circumferential sleeve assembly (3) is coaxially arranged outside the inner circumferential sleeve assembly (2), its inner wall is attached to the outer wall of the inner circumferential sleeve assembly (2), and the outer wall is in contact with the soil mass (W); the materials of the inner circumferential sleeve assembly (2) and the outer circumferential sleeve assembly (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, characterized in that The inner circumferential sleeve assembly (2) includes an inner circumferential sleeve housing and a first filling layer arranged inside the inner circumferential sleeve housing; the material of the inner circumferential sleeve housing is a brittle material; the filling material of the first filling layer includes gravel particles, ceramic particles and glass particles.

3. The improved sleeve valve pipe grouting experimental device according to claim 2, wherein, 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.

4. The improved sleeve valve pipe grouting experimental device according to claim 1, wherein The outer circumferential sleeve assembly (3) includes an outer circumferential sleeve housing and a second filling layer arranged inside the outer circumferential sleeve housing; the materials of the outer circumferential sleeve housing and the second filling layer are both bentonite.

5. The improved sleeve valve pipe grouting experimental device according to claim 1, wherein, The number of the first sealing members (4) includes one to multiple; when the number of the first sealing members (4) is multiple, the first sealing members (4) are sequentially stacked on one axial end of the circumferential gap.

6. The improved sleeve valve pipe grouting experimental device according to claim 1, wherein The number of the second sealing members (5) includes one to multiple; when the number of the second sealing members (5) is multiple, the second sealing members (5) are sequentially stacked on the other axial end of the circumferential gap.

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

8. An experimental method using the improved sleeve valve pipe grouting experimental device according to any one of claims 1-7, characterized in that, It includes: Step S1: Use an external grouting device to pressurize and grout into the grouting pipe (1), and the grout fills the sealed pressure chamber (6) in a sputtering manner through the grouting ports (1.1); meanwhile, the grout flowing into the sealed pressure chamber (6) has kinetic energy, which can continuously impact the inner circumferential sleeve assembly (2), forcing the inner circumferential sleeve assembly (2) to generate cracks and break, forming a plurality of first fragments; Step S2: Continue to use an external grouting device to pressurize and grout into the grouting pipe (1). The grout carries the first fragments and continuously impacts and collides with the circumferential outer casing assembly (3) until cracks are generated in the circumferential outer casing assembly (3) and it breaks into multiple second fragments. Subsequently, the grout uniformly diffuses into the soil mass (W) to reinforce the soil layer, and the first fragments and the second fragments carried by the grout extrude the soil mass (W) to improve the bearing capacity of the soil mass (W).

9. The experimental method according to claim 8, wherein The pressure for the pressurized grouting is 0.6 - 2.0 MPa.

10. The experimental method according to claim 8, wherein 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 circumferential inner casing assembly (2) and the outer diameter of the grouting pipe (1).

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