Method for improving recharge pressure of recharge well through sleeve valve pipe grouting
By filling filter materials and clay balls in the refilling well and using sleeve valve pipe grouting technology, the problems of groundwater seepage and pressurized refilling during foundation pit construction are solved, the refilling pressure and rate are improved, and the soil is compact. reduces construction difficulty and cost.
Patent Information
- Application Number
- CN202411622122.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-14
- Publication Date
- 2024-12-17
AI Technical Summary
In foundation pit construction, traditional groundwater control methods are difficult to effectively cut off groundwater seepage inside and outside the foundation pit, resulting in the drop of groundwater level outside the foundation pit and the settlement of strata. The pressurized reinfusion method is easy to cause hydraulic splitting and reinfusion, which affects the phenomenon of water reinfusion and reinfusion. Construction difficulty and cost.
After the return well and observation wells are holed, filter material and clay balls are filled and grouted using sleeve valve pipes, the grouting is ensured to uniformly grout and squeeze soil, increase the return pressure and return rate, and prevent water influx channels. Formation.
Effectively improve the return injection pressure and return injection rate of the refilling well, prevent the sealing of the well wall and the drilling gap, ensure the compactness of the soil, avoid hydraulic splitting and return during pressurized refilling, and reduce construction Difficulty and cost.
Smart Images
Figure CN119145419A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of foundation pit construction, and in particular to a method for increasing the recharging pressure of a recharging well through sleeve valve pipe grouting. Background Art
[0002] In actual projects, when the foundation pit is too deep or the aquifer is too thick, the depth of the water-stop curtain required to cut off the hydraulic continuity inside and outside the foundation pit is very large, which makes the construction difficult, the cost high, and the quality of anti-seepage difficult to guarantee. Therefore, in engineering practice, a suspended water-stop curtain is often used. At this time, the water-stop curtain cannot completely cut off the groundwater seepage inside and outside the foundation pit, resulting in the connection of groundwater inside and outside the foundation pit, which causes the groundwater level outside the pit to drop and the formation to settle. In addition, the hydrogeological conditions in soft soil areas are complex, and the confined aquifer often forms a layered distribution with the relative impermeable layer between them, and there is often overflow between aquifers. Even if the water-stop curtain cuts off a layer of confined water, pumping water from this layer will cause the water head of several layers of aquifers above and below to change due to overflow and cause settlement outside the foundation pit. In view of the limitations of traditional groundwater control methods when used in the above-mentioned situations, in recent years, the development has been to set up recharge wells near the protected buildings outside the foundation pit. For the aquifer outside the foundation pit whose water level has dropped due to precipitation in the foundation pit, artificial groundwater recharge measures are taken to effectively control the drop in groundwater level outside the foundation pit caused by precipitation in the foundation pit, thereby reducing or eliminating the impact of pumping water in the foundation pit and controlling ground subsidence and the resulting subsidence of the protected buildings.
[0003] The recharge methods of groundwater recharge wells can be divided into natural recharge relying on the deadweight of the water body and pressure recharge relying on artificial pressure. The water level in the natural recharge well is not higher than the wellhead, and no additional pressure is required, so it is widely used in engineering. Although pressurized recharge can increase the recharge volume of the recharge well, improper pressurization operation or excessive pressure can easily cause hydraulic fracturing, causing the recharged water to flow back along the weak surface of the soil layer, such as the contact surface between the well wall and the soil or the borehole that is not tightly blocked, etc. There are few actual engineering applications, so it is necessary to improve and optimize the pressurized recharge.
[0004] In view of the above problems, a method of increasing the reinjection pressure of reinjection wells by sleeve valve pipe grouting was proposed. Summary of the invention
[0005] The object of the present invention is to provide a method for increasing the recharging pressure of a recharging well by grouting with a sleeve valve pipe, so as to solve the above-mentioned problem.
[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions: A method for increasing the recharging pressure of a recharging well by grouting with a sleeve valve pipe comprises the following steps: S1. When constructing a reinjection well, drill a hole on the ground to complete the construction of the reinjection well and the observation well nearby; S2. When the drilling of the reinjection well and the observation well near the reinjection well is completed, the well pipe is lowered into the reinjection well; S3. Fill filter material at the bottom of the gap between the well pipe and the wall of the recharging well to a certain depth; S4. After the filter material is filled, lower the sleeve valve pipe to the top of the filter material; S5, then lowering the clay ball to the outside of the sleeve valve pipe, and the clay ball fills the gap between the well pipe and the wall of the reinjection wellbore; S6. After backfilling the clay balls, grouting is carried out. The grouting slurry is injected into the soil through the sleeve valve pipe. Be careful not to block the filter material during the grouting process.
[0007] As a preferred solution of the present invention, in step S2, the diameter of the well pipe is smaller than the inner diameter of the reinjection well.
[0008] As a preferred solution of the present invention, in step S5, the opening depth range of the sleeve valve tube is the filling range of the clay ball.
[0009] As a preferred solution of the present invention, in step S6, the thickness of the filter material is equal to the radius of the wellbore of the reinjection well minus the radius of the well pipe.
[0010] As a preferred solution of the present invention, a plurality of grouting ports are evenly opened on the outer wall of the sleeve valve pipe grouting port, and all of the grouting ports are connected to the gap between the well pipe and the wall of the reinjection well.
[0011] As a preferred solution of the present invention, in step S6, the filter material is made of medium-coarse sand material.
[0012] As a preferred solution of the present invention, the outer soil layer of the recharging well is divided into an impermeable layer and an aquifer, the impermeable layer is silty soil, and the aquifer is sandy soil.
[0013] As a preferred solution of the present invention, a well filter is provided on the inner bottom wall of the well pipe, the thickness of the well filter is equal to the thickness of the wall of the recharging well, and the thickness of the well filter corresponds to the aquifer.
[0014] Compared with the prior art, the present invention has the following beneficial effects: After the drilling of the recharge well and the observation well near the recharge well is completed, the well pipe is lowered and the filter material is buried, the sleeve valve pipe is lowered, and clay balls are backfilled after the sleeve valve pipe is lowered, and grouting is performed after the clay balls are backfilled, thereby ensuring the backfill quality between the clay balls and the hole wall, and grouting can be performed on the clay balls at different depths, the grouting position is more uniform, and the soil bodies at different depths are compacted at the same time, making the soil bodies denser, avoiding the generation of water gushing channels under a relatively small recharge pressure during pressurized recharge; and, in the recharge well and the adjacent observation well, the grouting method can be used to block the gap between the well wall and the borehole, thereby increasing the limit recharge pressure and the recharge rate, and preventing the test well from being damaged due to failure. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.
[0016] Figure 1 The present invention provides a flow chart of a method for increasing the recharging pressure of a recharging well by grouting with a sleeve valve pipe; Figure 2 The present invention provides a structural schematic diagram of a method for increasing the recharging pressure of a recharging well through sleeve valve pipe grouting.
[0017] The numbers in the figure represent the following: 1. Well pipe; 2. Recharge well; 3. Clay ball; 4. Filter material; 5. Well filter; 6. Water-proof layer; 7. Aquifer; 8. Sleeve valve pipe; 9. Grouting port. DETAILED DESCRIPTION
[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.
[0019] like Figure 1-Figure 2 As shown, the present invention provides a method for increasing the recharging pressure of a recharging well by grouting with a sleeve valve pipe, the method comprising the following steps: S1. When constructing the recharging well 2, drilling a hole on the ground to complete the construction of the recharging well 2 and the observation well nearby; S2. After the drilling of the recharge well 2 and the observation well near the recharge well 2 is completed, the well pipe 1 is lowered into the recharge well 2; the observation well is used to monitor the changes in the water level near the recharge well 2, and to timely adjust the recharge strategy and maintain the stability of the groundwater level by monitoring the water level changes and deformation of the surrounding environment in the observation well. The coordinated use of the recharge well 2 and the observation well can effectively control the settlement, protect the surrounding buildings and underground pipelines, and the data of the observation well can be used to guide the control of the recharge pressure to prevent water seepage or other unforeseen hazards in the recharge well 2 caused by excessive recharge pressure; S3, fill the filter material 4 to a certain depth at the bottom of the gap between the well pipe 1 and the wall of the recharging well 2; the filter material 4 is made of medium-coarse sand material. The filter material 4 plays a role of preliminary filtration, because there is too much mud in the well hole of the recharging well 2 that has just been drilled, and the water is too turbid, so by setting the filter material 4, the medium-coarse sand in the filter material 4 can filter the water, which can filter out larger impurities and prevent them from entering the well; S4. After the filter material 4 is filled, the sleeve valve pipe 8 is lowered to the top of the filter material 4; the sleeve valve pipe 8 can better control the grouting range and grouting pressure, and realize fixed depth, quantitative, sequential, segmented, intermittent and repeated grouting; ensure that the reinjection water is accurately injected into the target formation to avoid unnecessary waste of water resources and environmental impact; S5, then lower the clay ball 3 to the outside of the sleeve valve tube 8, and the clay ball 3 fills the gap between the well pipe 1 and the wall of the reinjection well 2; throw the dry clay ball 3 into the gap between the well pipe 1 and the wall of the reinjection well 2, and the clay ball 3 absorbs water to become silt. The setting of the clay ball 3 can play a role in water isolation and avoid hydraulic connection; S6. After the backfilling of the clay balls 3 is completed, grouting is performed. A plurality of grouting ports 9 are evenly opened on the outer wall of the sleeve valve pipe 8. All grouting ports 9 are connected to the gap between the well pipe 1 and the wall of the recharging well 2. The grouting slurry is injected into the soil through the plurality of grouting ports 9 on the outer wall of the sleeve valve pipe 8. During the grouting process, be careful not to block the filter material 4. During grouting, due to the high formation pressure, the slurry generally moves upwards, so that the clay balls 3 can be filled densely. At the same time, the grouting position should not be too close to the top plate of the aquifer 7 to avoid the slurry blocking the filter material 4. The arrangement of multiple grouting ports 9 can connect the gap between the well pipe 1 and the wall of the reinjection well 2 so that the slurry can be evenly injected into the soil. The present invention can inject grout into the clay balls 3 at different depths, and the grouting position is more uniform. At the same time, the soil at different depths is compacted to make the soil denser, thereby avoiding the problem of water gushing at the weak points between the clay balls 3 and the hole wall due to excessive local pressure during pressurized reinjection.
[0020] In step S2, the diameter of the well pipe 1 is smaller than the inner diameter of the recharging well 2. When drilling the recharging well 2, a hole is first drilled in the formation with a drill bit, and then the well pipe 1 is lowered into the hole section by section. Therefore, the diameter of the well pipe 1 needs to be smaller than the inner diameter of the recharging well 2 to facilitate the lowering of the well pipe 1 and to help form a gap between the well pipe 1 and the well wall, which is convenient for subsequent grouting and filling of filter material 4.
[0021] In step S5, the opening depth range of the sleeve valve tube 8 is the filling range of the clay ball 3 to ensure the grouting effect.
[0022] In step S6, the thickness of the filter material 4 is equal to the radius of the wellbore of the recharging well 2 minus the radius of the well pipe 1, which can ensure that the filter material 4 can effectively fill the gap and preliminarily purify and filter the groundwater.
[0023] The outer soil layer of the recharge well 2 is divided into an aquiclude 6 and an aquifer 7. The aquiclude 6 contains muddy soil, and the aquifer 7 contains sandy soil. The muddy soil in the aquiclude 6 is silt and clay, and it is difficult for water to flow in it. The permeability coefficient of the aquiclude 6 is very small, and the permeability is very poor. The aquiclude 6 can prevent cross-contamination between different water layers and ensure the purity of the recharged water. The aquifer 7 contains sandy soil, and the permeability of water in it is very strong, which is conducive to the recharge of groundwater.
[0024] A well filter 5 is arranged on the inner bottom wall of the well pipe 1, and the thickness of the well filter 5 is equal to the thickness of the wall of the recharging well 2, and the thickness of the well filter 5 corresponds to the aquifer 7. The aquifer 7 can be effectively protected to prevent impurities from entering, which helps to improve the filtering effect.
[0025] After the drilling of the recharge well 2 and the observation well near the recharge well 2 is completed, the well pipe 1 is lowered and the filter material 4 is buried. The sleeve valve pipe 8 is lowered, and the clay ball 3 is backfilled after the sleeve valve pipe 8 is lowered. Grouting is performed after the backfilling of the clay ball 3 is completed, so that the soil density around the recharge well 2 can be increased, thereby ensuring the backfill quality between the clay ball 3 and the hole wall. Grouting can be performed at different depths of the clay ball 3, and the grouting position is more uniform. At the same time, the soil at different depths is compacted, making the soil denser, avoiding the generation of a gushing channel under a smaller recharge pressure during pressurized recharge; and, in the recharge well 2 and the adjacent observation well, the grouting method can be used to block the gap between the well wall and the borehole, thereby increasing the limit recharge pressure and the recharge rate, and preventing the test well from being damaged due to failure.
[0026] The protection scope of the application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the application within the essence and protection scope of the application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the application.
Claims
1. A method for increasing the recharging pressure of a recharging well by grouting with a sleeve valve pipe, It is characterized in that The method comprises the following steps: S1. When constructing the reinjection well (2), drilling a hole on the ground to complete the construction of the reinjection well (2) and the observation well nearby; S2, when the drilling of the reinjection well (2) and the observation well near the reinjection well (2) is completed, the well pipe (1) is lowered into the reinjection well (2); S3, filling filter material (4) to a certain depth at the bottom of the gap between the well pipe (1) and the wall of the recharging well (2); S4. After the filter material (4) is filled, the sleeve valve tube (8) is lowered to the top of the filter material (4); S5, then lowering the clay ball (3) to the outside of the sleeve valve tube (8), and the clay ball (3) fills the gap between the well pipe (1) and the hole wall of the reinjection well (2); S6. After the backfilling of the clay balls (3) is completed, grouting is performed. The grouting slurry is injected into the soil through the sleeve valve pipe (8). During the grouting process, care is taken not to block the filter material (4).
2. A method for increasing the recharging pressure of a recharging well by grouting with a sleeve valve pipe according to claim 1, Features: In step S2, the diameter of the well pipe (1) is smaller than the inner diameter of the reinjection well (2).
3. A method for increasing the recharging pressure of a recharging well by grouting with sleeve valve pipes according to claim 1, Features: In step S5, the opening depth range of the sleeve valve tube (8) is the filling range of the clay ball (3).
4. A method for increasing the recharging pressure of a recharging well by grouting with sleeve valve pipes according to claim 1, Features: In step S4, the thickness of the filter material (4) is equal to the radius of the wellbore of the reinjection well (2) minus the radius of the well pipe (1).
5. A method for increasing the recharging pressure of a recharging well by grouting with sleeve valve pipes according to claim 1, Features: The outer wall of the grouting port (9) of the sleeve valve pipe (8) is evenly provided with a plurality of grouting ports (9), and all of the grouting ports (9) are connected to the gap between the well pipe (1) and the wall of the reinjection well (2).
6. A method for increasing the recharging pressure of a recharging well by grouting with sleeve valve pipes according to claim 1, Features: In step S4, the filter material (4) is made of medium-coarse sand material.
7. A method for increasing the recharging pressure of a recharging well by grouting with sleeve valve pipes according to claim 1, Features: The outer soil layer of the recharging well (2) is divided into an aquiclude (6) and an aquifer (7); the aquiclude (6) contains muddy soil, and the aquifer (7) contains sandy soil.
8. A method for increasing the recharging pressure of a recharging well by grouting with sleeve valve pipes according to claim 1, Features: A well filter (5) is provided on the inner bottom wall of the well pipe (1), the thickness of the well filter (5) is equal to the thickness of the wall of the recharging well (2), and the thickness of the well filter (5) corresponds to the aquifer (7).