Pressurized post-grouting device and process for dewatering well

Abstract

The invention discloses a pressurized post-grouting device and process for a dewatering well, and the pressurized post-grouting device comprises a well pipe, the filter pipe section of the well pipe is located in an underground aquifer area, and the space between the filter pipe section and the aquifer is filled with a filter material; the first grouting pipe extends into the well casing from top to bottom, the lower end of the first grouting pipe is a grout outlet end, and the first grouting pipe is used for grouting for the first time and discharging grout in the well to form a first grouting body; the second grouting pipe extends into the well pipe from top to bottom, the lower end of the second grouting pipe is a grout outlet end, the grout outlet end of the second grouting pipe is located in the primary grouting body, secondary grout outlet in the primary grouting body forms a secondary grouting splitting channel communicated with the filter holes of the filter pipe section, and the secondary grouting splitting channel forms a high-pressure grouting channel. The grouting sealing cover body is formed in the well through primary grouting, then pores of the filter pipe, the well casing and the hole wall can be completely blocked through secondary pressurized grouting, and the risk of sudden gushing of the foundation pit at the dewatering well is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit engineering, in particular to a pressurized post-grouting device and process for a dewatering well. Background Art

[0002] In hydrogeological surveys and tests and foundation pit engineering dewatering, it is necessary to construct dewatering wells. Dewatering wells are filter pipes placed in underground aquifers to pump groundwater and lower the groundwater level. Before the foundation pit is completed and dewatering is stopped, the dewatering wells within the foundation pit need to be sealed to prevent groundwater from gushing out of the foundation pit floor along the leakage channel after recovery. The existing technology for sealing wells generally uses bentonite and cement slurry to flow naturally into the well pipe, and fills in stone chips for grouting. Although this method can seal the filter pipe, the gaps between the well pipe and the hole wall are difficult to fill densely, and there is still a risk of leakage. Summary of the invention

[0003] The purpose of the present invention is to provide a pressurized post-grouting device and process for a dewatering well to solve the problems existing in the prior art.

[0004] The object of the present invention is achieved in this way: a pressurized post-grouting device for a precipitation well, comprising:

[0005] The well pipe has a filter pipe section with a plurality of filter holes at its lower part, the filter pipe section is located in the underground aquifer area, and filter material is filled between the filter pipe section and the aquifer;

[0006] At least one first grouting pipe extending from top to bottom into the well pipe, the lower end of which is set as a grouting end, which is used for initial grouting and grouting in the well to form a first grouting body;

[0007] At least one second grouting pipe extends from top to bottom into the well pipe, and its lower end is set as a grouting end. The grouting end of the second grouting pipe is located in the primary grouting body, and a secondary grouting is discharged in the primary grouting body to form a secondary grouting splitting channel connected to the filter holes of the filter pipe section. The secondary grouting splitting channel constitutes a high-pressure grouting channel.

[0008] As another aspect of the present invention, a grouting process is proposed based on the above grouting device, comprising the following steps:

[0009] The first grouting is to inject grout into the well pipe from the first grouting pipe. The grout of the first grouting forms the first grouting body after initial solidification and meets the thickness of the covering layer.

[0010] Secondary grouting: grouting is carried out from the second grouting pipe into the well pipe under pressure, and a secondary grouting splitting channel is formed by impact in the first grouting body;

[0011] Continue grouting at a certain pressure, and the cement slurry gradually penetrates the filter pipe section to fill the filter material and the pores between the well pipe and the hole wall.

[0012] The beneficial effects of the present invention are:

[0013] A grouting capping body is formed in the well through the first grouting, and then through the secondary pressurized grouting, a secondary grouting is produced in the first grouting body to form a secondary grouting splitting channel connected to the filter holes of the filter pipe section. The cement slurry passes through the secondary grouting splitting channel, and the cement slurry gradually penetrates the filter pipe section to fill the filter material and fills the pores between the well pipe and the hole wall, which can achieve comprehensive blocking of the pores in the filter pipe, well pipe and hole wall, reducing the risk of sudden surges in the foundation pit at the precipitation well. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention.

[0015] Explanation of the accompanying drawings: 1-1 first grouting pipe; 1-2 second grouting pipe; 2 first grouting body; 3 one-way grouting hole; 4 secondary grouting splitting channel; 5 well pipe; 6 filter pipe section; 7 hole wall; 8 filter material; 9 pores. DETAILED DESCRIPTION

[0016] The following will be combined with the attached embodiment of the present invention Figure 1 , the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] like Figure 1 As shown, a pressurized post-grouting device for a dewatering well is provided, which can achieve comprehensive blocking of the pores among the filter pipe, the well pipe and the hole wall through pressurized grouting, thereby reducing the risk of sudden surges in the foundation pit at the dewatering well.

[0018] The above-mentioned grouting device comprises:

[0019] The well pipe 5 has a filter pipe section 6 with a plurality of filter holes at its lower part, the filter pipe section 6 is located in the underground aquifer area, and a filter material 8 is filled between the filter pipe section 6 and the aquifer. The well pipe 5 is fixedly inserted into the wellbore, and a pore 9 is formed between the well pipe 5 and the hole wall 7 of the wellbore;

[0020] A first grouting pipe 1-1 extending from top to bottom into the well pipe 5, with its lower end being a grouting end, which is used for initial grouting and grouting out in the well to form a first grouting body 2;

[0021] A second grouting pipe 1-2 extends from top to bottom into the well pipe 5, and its lower end is set as a slurry outlet end. The slurry outlet end of the second grouting pipe 1-2 is in the primary grouting body 2, and a secondary grouting is discharged in the primary grouting body 2 to form a secondary grouting splitting channel 4 connected to the filter holes of the filter pipe section 6. The secondary grouting splitting channel 4 constitutes a high-pressure grouting channel.

[0022] Among them, the secondary grouting splitting channel 4 is completely inside the first grouting body 2. During the first grouting, grouting is performed from the first grouting pipe 1-1 into the well pipe 5. After the initial setting of the slurry of the first grouting, the first grouting body 2 is formed and the thickness of the covering layer is met. The second grouting begins, and the second grouting pipe 1-2 is pressurized into the well pipe 5. Since the first grouting body 2 is initially set, a capping body is formed in the one-way slurry outlet hole 3 of the second grouting pipe 1-2, a relatively closed space is formed, and high pressure is formed under continuous grouting. Since the strength of the first grouting body 2 is not high after the initial setting, the slurry in the high-pressure state is easy to impact in the first grouting body 2 to form a secondary grouting splitting channel 4.

[0023] The outlet ends of the first grouting pipe 1-1 and the second grouting pipe 1-2 are both provided with one-way grouting holes 3 to prevent the slurry from flowing back and ensure that the slurry can only flow in one direction from the grouting pipe to the well pipe.

[0024] The one-way slurry outlet holes 3 of the first grouting pipe 1-1 and the second grouting pipe 1-2 are located within the depth range of the filter pipe section 6 at the bottom of the well pipe 5 to ensure the slurry circulation effect.

[0025] The upper ends of the first grouting pipe 1-1 and the second grouting pipe 1-2 are connected to the high-pressure grouting device during grouting, so that slurry with a certain pressure is injected into the well pipe 5 through the first grouting pipe 1-1 and the second grouting pipe 1-2 in sequence.

[0026] Embodiment 1

[0027] During the first grouting, cement slurry is injected into the well pipe 5 from the first grouting pipe 1-1. When the slurry of the first grouting is initially solidified, a first grouting body 2 is formed and the requirement of the covering layer thickness is met.

[0028] The second grouting begins, and cement slurry is injected into the well pipe 5 from the second grouting pipe 1-2 under pressure. After the initial setting of the first grouting body 2, a capping body is formed in the one-way grouting hole 3 of the second grouting pipe 1-2, forming a relatively closed space, and high pressure is formed under continuous grouting. Since the strength of the first grouting body 2 is not high after the initial setting, the slurry in the high-pressure state is easy to impact in the first grouting body 2 to form a secondary grouting splitting channel 4. The cement slurry passes through the secondary grouting splitting channel 4, and the cement slurry gradually penetrates the filter section 6 to fill the filter material 8, and fills the pores 9 between the well pipe 5 and the hole wall 7.

[0029] Embodiment 2

[0030] When this embodiment is in operation, the following steps are followed:

[0031] S1. Place the first grouting pipe 1-1 and the second grouting pipe 1-2 into the well pipe 5 to be sealed, and ensure that the one-way grouting hole 3 at the end thereof is within the depth range of the filter pipe section 6 of the well pipe 5;

[0032] S2. Ordinary silicate cement slurry is injected into the well pipe 5 through the first grouting pipe 1-1, and the first grouting body 2 is formed after the initial setting of the cement slurry;

[0033] S3. Measure the depth of the first grouting body 2 to ensure that the first grouting body 2 covers a thickness greater than 10 times the diameter of the well pipe 5, and ensure that the second pressure grouting fluid will not split the first grouting body 2 and gush along the well; if the coverage thickness is not met, use fast-hardening and high-strength high-aluminum cement slurry for supplementation;

[0034] S4. Inject ordinary silicate cement slurry into the well pipe 5 through the second grouting pipe 1-2 under pressure, and perform grouting at a pressure of 0.5-1 MPa; when the grouting pressure suddenly decreases, it is considered that the cement slurry impacts the first grouting body 2 to form a secondary grouting splitting channel 4, and a part of the secondary grouting splitting channel 4 penetrates the filter pipe section 6;

[0035] S5. Continue grouting at a pressure of 0.3 to 0.5 MPa, and the cement slurry gradually penetrates the filter pipe section 6 to fill the filter material 8 and also fills the pores 9 between the well pipe 5 and the hole wall 7;

[0036] S6. Backfill the well pipe 5 with soil and sand and gravel to the ground.

[0037] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention; in the present invention, it should also be noted that the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, an integrally formed connection, a mechanical connection, or an indirect connection through an intermediate connecting component, and the specific meaning of the terms in this utility model can be understood according to the specific circumstances.

[0038] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0039] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A pressurized post-grouting device for a dewatering well, characterized in that: include: A well pipe (5), the lower part of which is provided with a filter pipe section (6) with a plurality of filter holes, the filter pipe section (6) is located in an underground aquifer area, and a filter material (8) is filled between the filter pipe section (6) and the aquifer; At least one first grouting pipe (1-1) extending from top to bottom into the well pipe (5), the lower end of which is set as a grouting end, which is used for initial grouting and grouting in the well to form a primary grouting body (2); At least one second grouting pipe (1-2) extends from top to bottom into the well pipe (5), and its lower end is set as a grouting end. The grouting end of the second grouting pipe (1-2) is located in the primary grouting body (2), and secondary grouting is conducted in the primary grouting body (2) to form a secondary grouting splitting channel (4) connected to the filter holes of the filter pipe section (6). The secondary grouting splitting channel (4) constitutes a high-pressure grouting channel.

2. A pressurized post-grouting device for a dewatering well according to claim 1, characterized in that: The secondary grouting splitting channel (4) is completely located inside the primary grouting body (2).

3. A pressurized post-grouting device for a dewatering well according to claim 2, characterized in that: The covering thickness of the first grouting body (2) is greater than 10 times the diameter of the well pipe (5).

4. A pressurized post-grouting device for a dewatering well according to claim 1, characterized in that: The slurry outlet ends of the first grouting pipe (1-1) and the second grouting pipe (1-2) are both provided with one-way slurry outlet holes (3).

5. A pressurized post-grouting device for a dewatering well according to claim 4, characterized in that: The one-way grouting holes (3) of the first grouting pipe (1-1) and the second grouting pipe (1-2) are located within the depth range of the filter pipe section (6) at the bottom of the well pipe (5).

6. A pressurized post-grouting device for a dewatering well according to any one of claims 1 to 5, characterized in that: The upper ends of the first grouting pipe (1-1) and the second grouting pipe (1-2) are connected to the high-pressure grouting device during grouting.

7. A grouting process using the pressurized post-grouting device for a dewatering well according to claim 1, characterized in that: The steps include: The first grouting is performed by injecting grout from the first grouting pipe (1-1) into the well pipe (5), and the slurry of the first grouting is initially solidified to form a first grouting body (2) and meet the thickness of the covering layer; Secondary grouting, grouting is performed under pressure from the second grouting pipe (1-2) into the well pipe (5), and a secondary grouting splitting channel (4) is formed by impact in the first grouting body (2); The grouting is continued at a certain pressure, and the cement slurry gradually penetrates the filter pipe section (6) to fill the filter material (8) and the pores (9) between the well pipe (5) and the hole wall (7).

8. A grouting process according to claim 7, characterized in that: The method further comprises a step of measuring the depth of the first grouting body (2), which is performed after the first grouting and before the second grouting, and comprises the following process: The depth of the first grouting body (2) is measured to ensure that the coverage thickness of the first grouting body (2) meets the construction requirements and to ensure that the second pressure grouting fluid will not split the first grouting body (2) and gush along the well.

9. A grouting process according to claim 8, characterized in that: In the step of measuring the depth of the first grouting body (2), if the coverage thickness of the first grouting body (2) does not meet the construction requirements, a quick-hardening high-strength grouting material is used for supplementation.

10. A grouting process according to claim 7, characterized in that: During the secondary grouting process, when the grouting pressure suddenly decreases, it is considered that the cement slurry impacts the first grouting body (2) to form a secondary grouting splitting channel (4), and a part of the secondary grouting splitting channel (4) penetrates the filter pipe section (6).

Images