A method for plugging a deep foundation pit confined water dewatering well

Abstract

The application discloses a deep foundation pit confined water dewatering well plugging method, which comprises the following steps: firstly backfilling the deep foundation pit with sand and stones, wherein the distance between the backfilling surface of the first backfilling and the bottom surface of the bottom plate is greater than or equal to a set value; lowering a water pump and a sleeve, wherein the water outlet of the water pump is connected with the lower end of a water belt, and the sleeve is sleeved on the water belt; secondly backfilling with sand and stones, wherein the backfilling surface of the second backfilling is flush with the bottom surface of the bottom plate; pouring micro-expansion concrete; and plugging the sleeve. The technical scheme provided by the embodiment of the application adopts the sleeve pre-embedded water pump concept, utilizes the '211' technical construction of twice backfilling, once well sealing and once pipe sealing, has strong actual operability, is suitable for large dewatering wells, especially suitable for deep foundation pit confined water, is convenient to construct, is economic and suitable, can improve the efficiency and the plugging quality, and is especially suitable for use in a construction site.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a method for sealing confined water dewatering wells in deep foundation pits. Background Technology

[0002] With the development of society, high-rise buildings are springing up everywhere, and two-story basements are becoming increasingly common. In construction projects, there are more and more deep foundation pit basement structures. Deep foundation pits are generally confined to water, and sealing confined water dewatering wells is extremely difficult, making it hard to achieve a good sealing effect.

[0003] In existing technology, the sealing method for dewatering wells includes: filling with sand and gravel 01, filling and compacting with expansive concrete 02, placing a steel plate 06 on top of the expansive concrete 02, fully welding the steel plate 06 to the wellhead, and installing a water-stop strip 05 and a water-stop plate 04 on the expansive concrete at the bottom plate 03, thereby sealing the dewatering well. Please refer to [reference needed]. Figure 1 , Figure 1 This is a schematic diagram of the sealing of a typical small wellpoint dewatering well in the prior art.

[0004] However, while this method can be used to seal small wellpoint dewatering wells with low water pressure, the dewatering wells in deep foundation pits are generally faced with pressurized water with high water pressure and large wells. It is impossible to stop the pump and pour concrete, as all the cement will be washed away, and the actual sealing effect will not be achieved.

[0005] In summary, how to effectively solve the problem of the difficulty in sealing the dewatering wells of confined water in deep foundation pits is an urgent problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for sealing confined water dewatering wells in deep foundation pits. This method is convenient for sealing confined water in deep foundation pits, and improves sealing efficiency and quality.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] A method for sealing confined water dewatering wells in deep foundation pits includes the following steps:

[0009] The first backfilling of the deep foundation pit is carried out with sand and gravel, and the distance between the backfill surface and the bottom surface of the slab is greater than or equal to the set value.

[0010] A water pump and a sleeve are lowered, with the outlet of the water pump connected to the lower end of the water hose, and the sleeve fitted onto the water hose;

[0011] Secondary backfilling is carried out using sand and gravel, and the backfill surface of the secondary backfill is flush with the bottom surface of the base slab.

[0012] Pouring micro-expansion concrete;

[0013] The sleeve is sealed.

[0014] Optionally, between the secondary backfilling with sand and gravel and the pouring of micro-expansion concrete, the method further includes: setting an isolation layer at the opening of the backfill surface of the secondary backfill, and pouring the micro-expansion concrete on the isolation layer.

[0015] Optionally, the strength grade of the micro-expansion concrete is higher than that of the concrete in the base slab.

[0016] Optionally, sealing the sleeve includes:

[0017] The concrete was sealed in woven bags to form mud balls;

[0018] Stop the water pump;

[0019] Cut the water hose along the upper end of the sleeve and press the water hose into the sleeve;

[0020] Several of the mud balls are pressed into the inside of the sleeve;

[0021] After repeatedly pressing down on multiple mud balls, the water on top of the mud balls in the sleeve is sucked away;

[0022] Concrete was poured on top of the mud ball.

[0023] Optionally, before pouring concrete on top of the mud ball, the following steps are also included:

[0024] Measure whether the height of the top mud ball to the bottom slab is greater than the thickness of the bottom slab. If so, proceed with concrete pouring; otherwise, continue to hammer down the mud ball.

[0025] Check for water seepage. If there is no leakage, pour concrete. If there is seepage, add mud balls to seal it.

[0026] Optionally, before pouring the micro-expansion concrete, the following steps are also included:

[0027] Observe the condition of each rainwater well to ensure it is normal, and record and analyze the data.

[0028] The water-stop steel plate, concrete joint, and reinforcing steel of the reserved base plate are ground and roughened.

[0029] Optionally, before lowering the water pump and casing, the following are included:

[0030] The water pump inlet was wrapped with two layers of wire mesh;

[0031] A water-stop ring is welded to the position where the sleeve is located on the base plate.

[0032] Optionally, before lowering the water pump and the casing, the method includes welding the lower end of the casing to the water pump.

[0033] Optionally, before lowering the water pump and the casing, a plastic elbow is installed at the upper end of the casing.

[0034] Optionally, after installing a plastic elbow at the upper end of the sleeve, the method includes adding a protective layer to the plastic elbow.

[0035] The method for sealing the deep foundation pit confined water dewatering well provided by this invention includes the following steps: first backfilling the deep foundation pit with sand and gravel, wherein the distance between the backfill surface and the bottom surface of the base plate is greater than or equal to a set value; lowering a water pump and a casing, wherein the outlet of the water pump is connected to the lower end of the water hose, and the casing is fitted onto the water hose; second backfilling with sand and gravel, wherein the backfill surface of the second backfill is flush with the bottom surface of the base plate; pouring micro-expansion concrete; and sealing the casing.

[0036] The technical solution provided by the embodiments of the present invention adopts the concept of pre-embedded water pump in casing and uses the "211" technology of two backfills, one well sealing and one pipe sealing. It is highly operable, applicable to larger dewatering wells, especially suitable for deep foundation pits with confined water. It is convenient and economical to construct, which can improve efficiency and sealing quality. It is particularly suitable for use on construction sites. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the plugging of a typical small wellpoint dewatering well in the prior art;

[0039] Figure 2 The flowchart illustrates the implementation of a method for sealing confined water dewatering wells in deep foundation pits, as provided in a specific embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of the sealing of the deep foundation pit confined water dewatering well in this invention.

[0041] The following labels are shown in the attached diagram:

[0042] 1. Base plate, 2. Water-stop ring, 3. Isolation layer, 4. Secondary backfill, 5. Sleeve, 6. Water pump, 7. Wire mesh, 8. Initial backfill, 9. Plastic elbow. Detailed Implementation

[0043] The core of this invention is to provide a method for sealing confined water dewatering wells in deep foundation pits. This method seals the confined water in deep foundation pits, is convenient to construct, and improves sealing efficiency and quality.

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] See Figure 2 and Figure 3 As shown, Figure 3 This is a schematic diagram illustrating the sealing of the confined water dewatering well in the deep foundation pit according to the present invention. Figure 2 This is a flowchart illustrating an implementation method for sealing a deep foundation pit confined water dewatering well, as provided in an embodiment of this application. The method may include the following steps:

[0046] S110: Use sand and gravel to backfill the deep foundation pit for the first time 8. The distance between the backfill surface of the first backfill 8 and the bottom surface of the bottom plate 1 is greater than or equal to the set value.

[0047] In practical applications, graded crushed stone is used for backfilling. The distance between the backfill surface of the first backfill 8 and the bottom surface of the bottom plate 1 is greater than or equal to a set value. For example, the distance between the backfill surface of the first backfill 8 and the bottom surface of the bottom plate 1 is greater than or equal to 2000mm. That is, the height of the first backfill 8 is at least 2000mm from the bottom of the bottom plate 1. The distance is sufficient to ensure that there is water on the surface of the sand and gravel, and to ensure that the water pump 6 works normally.

[0048] S120: Lower the water pump 6 and the sleeve 5. The outlet of the water pump 6 is connected to the lower end of the water hose, and the sleeve 5 is fitted onto the water hose.

[0049] In practical applications, before lowering the water pump 6 and casing 5, the outlet of the water pump 6 is connected to the lower end of the water hose. The casing 5 is then fitted onto the water hose, completely encasing it. The casing 5, with its high strength and hardness, is not easily deformed, preventing crushed stones from crushing it and thus protecting the water hose from damage caused by backfill stones. After the water pump 6 and casing 5 are lowered to the backfill surface of the initial backfill 8, the water pump 6 draws water out of the well and discharges it through the water hose, ensuring normal sealing operations.

[0050] Optionally, the sleeve 5 can be made of galvanized steel pipe, such as a 2mm thick galvanized steel pipe with a diameter of 100mm. Galvanized steel pipe is thicker and stronger, making it less prone to damage. The inner diameter of the galvanized steel pipe is slightly larger than the outer diameter of the hose. The appropriate inner diameter makes it easy to fit the hose inside, reduces the difficulty of sealing the sleeve 5, reduces the amount of sealing concrete used, and saves materials.

[0051] S130: Use sand and gravel for secondary backfilling 4. The backfill surface of secondary backfill 4 is flush with the bottom surface of the base plate 1.

[0052] In practical applications, the secondary backfill should be carried out to the bottom of the foundation slab 1. The specific backfill location can be determined based on the actual water output in the well after the two backfills. Under favorable conditions, backfilling can be carried out to 200mm below the bottom of the foundation slab 1, allowing for a slightly larger concrete pour volume and better well sealing effect.

[0053] S140: Pouring micro-expansion concrete.

[0054] In practical applications, after the secondary backfill 4, micro-expansion concrete is poured on the backfill surface of the secondary backfill 4, and poured until the upper surface of the micro-expansion concrete is flush with the upper surface of the bottom plate 1, so as to ensure that the height of the deep foundation pit confined water dewatering well is consistent with the height of the bottom plate 1, and the overall surface is neat, flat and beautiful.

[0055] S150: Sealing sleeve 5.

[0056] In practical applications, after the concrete at the wellhead of the entire dewatering well has hardened and reached its strength, we generally start sealing the casing 5 after 7 days to complete the sealing of the entire dewatering well.

[0057] The technical solution provided by the embodiments of the present invention adopts the concept of pre-embedded water pump 6 in casing 5 and uses the "211" technology of two backfills, one well sealing and one pipe sealing. It is highly operable, applicable to larger dewatering wells, especially suitable for deep foundation pits with confined water. It is convenient and economical to construct, which can improve efficiency and sealing quality. It is particularly suitable for use on construction sites.

[0058] In one specific embodiment of this application, the following steps may be included between step S130 and step S140:

[0059] An isolation layer 3 is set at the opening of the backfill surface of the secondary backfill 4, and micro-expansion concrete is poured on the isolation layer 3.

[0060] In practical applications, in order to ensure the smooth pouring of concrete at the wellhead and the normal operation of the water pump 6, after the water pump 6 is lowered and the secondary backfill 4 is carried out, the wellhead needs to be treated. An isolation layer 3 is added at the wellhead, and micro-expansion concrete is poured on the isolation layer 3.

[0061] Optionally, the isolation layer 3 uses wire mesh 7 combined with geotextile. For example, a single layer of wire mesh 7 can be laid on the crushed stone surface of the secondary backfill 4. The wire mesh 7 has high strength and provides support for the micro-expansion concrete. At least two layers of geotextile are set on the wire mesh 7. The geotextile is lightweight, has high tensile strength, good permeability, high temperature resistance, freeze resistance, aging resistance, and corrosion resistance, and plays a role in isolation, filtration, and protection to prevent the crushed stone from being washed away.

[0062] In one specific embodiment of this application, the strength grade of the micro-expansion concrete is higher than that of the concrete in the base slab 1.

[0063] In practical applications, the strength of the poured concrete is increased by at least one grade compared to the original base slab 1. For example, if the base slab 1 is made of C35 micro-expansion concrete, the poured micro-expansion concrete is made of C40P8 micro-expansion concrete, thereby increasing the concrete strength and enhancing the water pressure bearing capacity.

[0064] In one specific embodiment of this application, step S140, sealing the sleeve 5, may include the following steps:

[0065] Step 1: Seal the concrete into woven bags to form mud balls;

[0066] Step 2: Stop the water pump 6;

[0067] Step 3: Cut the water hose along the upper end of the sleeve 5 and press the water hose into the sleeve 5;

[0068] Step 4: Press several mud balls into the inside of sleeve 5;

[0069] Step 5: After repeatedly pressing down on multiple mud balls, suck away the water from the top of the mud balls in sleeve 5;

[0070] Step 6: Pour concrete on top of the mud ball.

[0071] For ease of description, the above steps will be explained in combination below.

[0072] In practical applications, once the concrete at the wellhead of the overall dewatering system has hardened and reached its strength, the casing 5 is sealed. During the sealing process, woven bags are prepared before sealing, with at least three bags per well. Concrete is filled into the woven bags, forming a mud ball within them. It should be noted that the amount of concrete added should be appropriate so that the mud ball can be slowly pressed into the casing 5; the mud ball acts similarly to a rubber piston.

[0073] After the bagged mud balls are filled, immediately stop the water pump 6 and cut the water hose along the upper end of the sleeve 5. Press the water hose into the sleeve 5, stop pumping water with the water hose and the water pump 6, and clean the water hose outside the sleeve 5 to prepare for the subsequent pressing of mud balls and concrete pouring.

[0074] Next, slowly place the prepared mud balls into the sleeve 5. Use a wooden stick and a small protective steel pipe to strike and press the parts that cannot be put in into the sleeve 5. Repeat this process several times, for example, three mud balls, to compact the mud balls into the sleeve 5.

[0075] Use geotextile, towel or sponge to absorb the water on the top of the mud ball in casing 5, keeping the top of the mud ball dry. Then pour concrete on the mud ball to complete the sealing of casing 5.

[0076] The method of sealing the sleeve 5 is simple and easy to operate. The mud ball and the inner wall of the sleeve 5 are densely integrated into a whole, with high strength, not easy to be washed away, and convenient for subsequent concrete pouring.

[0077] In one specific embodiment of this application, before pouring concrete on top of the mud ball in step six, the following steps may be included:

[0078] Measure whether the height of the top mud ball to the bottom plate 1 is greater than the thickness of the bottom plate 1. If so, proceed with concrete pouring; if not, continue to hammer and press down the mud ball.

[0079] Check for water seepage. If there is no leakage, pour concrete. If there is seepage, add mud balls to seal it.

[0080] For ease of description, the above steps will be explained in combination below.

[0081] In practical applications, before pouring concrete on top of the mud ball, it is necessary to measure the height of the top mud ball to the bottom slab 1 and observe the water seepage effect. If the height of the mud ball to the bottom slab 1 is greater than the thickness of the bottom slab 1 and there is almost no leakage, the upper concrete can be poured. If the height is insufficient, it is necessary to continue to hammer and press down. If there is significant leakage in the mud ball, more mud balls should be added to seal it and ensure that the concrete can be poured smoothly.

[0082] In one specific embodiment of this application, the following steps may be included before pouring the micro-expansion concrete in step S140:

[0083] Observe the condition of each rainwater well to ensure it is normal, and record and analyze the data.

[0084] The waterstop steel plate, concrete interface and steel reinforcement of the reserved base plate 1 are ground and roughened.

[0085] In practical applications, before pouring micro-expansion concrete, the condition of each dewatering well should be observed to ensure it is functioning properly. If there is significant seepage, it needs to be addressed promptly to facilitate the smooth pouring of the micro-expansion concrete. Furthermore, after observation, a statistical record of the condition of each dewatering well should be kept, noting whether it is functioning normally and how any problems were handled. This record will provide a reference for the subsequent sealing of confined water dewatering wells in deep foundation pits.

[0086] Meanwhile, the pre-reserved water-stop steel plates, concrete joints, and reinforcing bars were all roughened and polished by personnel to ensure that the new and old concrete were poured and hardened tightly to prevent leakage.

[0087] In one specific embodiment of this application, the following steps may be included before step S120: [The steps described are missing from the original text.]

[0088] Wrap the inlet of the water pump 6 with two layers of wire mesh 7;

[0089] A water-stop ring 2 is welded to the position of the sleeve 5 at the base plate 1.

[0090] For ease of description, the above steps will be explained in combination below.

[0091] In practical applications, before the first backfill 8, the water pump 6 inlet is wrapped with several layers of wire mesh 7, such as two layers, to prevent sand and gravel particles from entering the water pump 6 during the subsequent second backfill 4, causing the water pump 6 to become clogged, unable to work, or burn out.

[0092] Before casing 5, casing 5 is processed for the reserved height of the first backfill 8. A water-stop ring 2 is welded on casing 5 at the position of bottom plate 1 to prevent groundwater from seeping upward along casing 5 after the concrete of the dewatering well of bottom plate 1 is poured.

[0093] In one specific embodiment of this application, before lowering the water pump 6 and the sleeve 5 in step S120, the following steps may be included: welding the lower end of the sleeve 5 to the water pump 6.

[0094] In practical applications, the lower end of the sleeve 5 is connected to the water pump 6 by welding, such as spot welding. The sleeve 5 and the water pump 6 form a whole. During the backfilling of sand and gravel, the sleeve 5 and the water pump 6 are not easily misaligned. The relative position of the sleeve 5 and the water pump 6 is determined to ensure smooth connection between the water hose and the water pump 6.

[0095] In one specific embodiment of this application, step S120 may include the following steps before the water pump 6 and the sleeve 5 are lowered: installing a plastic elbow 9 at the upper port of the sleeve 5.

[0096] In practical applications, since the sleeve 5 is a straight pipe and its upper end is relatively sharp, it is easy to cut the water hose. Therefore, a plastic elbow 9 is installed at the upper end of the sleeve 5. The water hose extends along the curvature of the plastic elbow 9 to protect the mouth of the hose and prevent the hose from being damaged due to continuous pumping and shaking.

[0097] In one specific embodiment of this application, after installing the plastic elbow 9 at the upper end of the sleeve 5, it may include: adding a protective layer to the plastic elbow 9.

[0098] In practical applications, during the pouring of micro-expansion concrete, the concrete may enter the sleeve 5, affecting the normal drainage of the hose. Therefore, additional protective measures are implemented at the plastic elbow 9, such as using tarpaulin to cover and seal the opening of the elbow 9, preventing the micro-expansion concrete from entering the sleeve 5 and ensuring the normal operation of the hose.

[0099] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0100] The above provides a detailed description of the method for sealing confined water dewatering wells in deep foundation pits provided by this invention. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this invention. Therefore, this invention is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for sealing confined water dewatering wells in deep foundation pits, characterized in that, Including the following steps: The first backfilling of the deep foundation pit is carried out with sand and gravel, and the distance between the backfill surface and the bottom surface of the slab is greater than or equal to the set value. Connect the outlet of the water pump to the lower end of the water hose, and fit the sleeve onto the water hose to form a pre-embedded water pump assembly; Lower the pre-embedded water pump assembly onto the backfill surface for the first backfilling; Secondary backfilling is carried out using sand and gravel, and the backfill surface of the secondary backfill is flush with the bottom surface of the base slab. Pouring micro-expansion concrete; The sleeve is sealed.

2. The method for sealing confined water dewatering wells in deep foundation pits according to claim 1, characterized in that, Between the secondary backfilling with sand and gravel and the pouring of micro-expansion concrete, the method further includes: setting an isolation layer at the opening of the backfill surface of the secondary backfill, and pouring the micro-expansion concrete on the isolation layer.

3. The method for sealing confined water dewatering wells in deep foundation pits according to claim 1, characterized in that, The strength grade of the micro-expansion concrete is higher than that of the concrete in the base slab.

4. The method for sealing confined water dewatering wells in deep foundation pits according to claim 1, characterized in that, Blocking the sleeve includes: The concrete was sealed in woven bags to form mud balls; Stop the water pump; Cut the water hose along the upper end of the sleeve and press the water hose into the sleeve; Several of the mud balls are pressed into the inside of the sleeve; After repeatedly pressing down on multiple mud balls, the water on top of the mud balls in the sleeve is sucked away; Concrete was poured on top of the mud ball.

5. The method for sealing confined water dewatering wells in deep foundation pits according to claim 4, characterized in that, Before pouring concrete on top of the mud ball, the following is also included: Measure whether the height of the top mud ball to the bottom slab is greater than the thickness of the bottom slab. If so, proceed with concrete pouring; otherwise, continue to hammer down the mud ball. Check for water seepage. If there is no leakage, pour concrete. If there is seepage, add mud balls to seal it.

6. The method for sealing confined water dewatering wells in deep foundation pits according to claim 1, characterized in that, Before pouring the micro-expansion concrete, the following steps are also included: Observe the condition of each rainwater well to ensure it is normal, and record and analyze the data. The water-stop steel plate, concrete joint, and reinforcing steel of the reserved base plate are ground and roughened.

7. The method for sealing confined water dewatering wells in deep foundation pits according to any one of claims 1-6, characterized in that, Before lowering the water pump and casing, including: The water pump inlet was wrapped with two layers of wire mesh; A water-stop ring is welded to the position where the sleeve is located on the base plate.

8. The method for sealing confined water dewatering wells in deep foundation pits according to claim 7, characterized in that, Before lowering the water pump and the casing, the procedure includes welding the lower end of the casing to the water pump.

9. The method for sealing confined water dewatering wells in deep foundation pits according to claim 7, characterized in that, Before lowering the water pump and the casing, a plastic elbow is installed at the upper end of the casing.

10. The method for sealing confined water dewatering wells in deep foundation pits according to claim 9, characterized in that, After installing the plastic elbow at the upper end of the sleeve, the method includes: adding a protective layer to the plastic elbow.

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