Municipal working well dewatering construction structure and construction method

Abstract

The invention discloses a municipal working well dewatering construction structure and a construction method. The construction structure comprises a precipitation well, a precipitation pipe is arranged in the precipitation well, a filter material is arranged between the precipitation pipe and the well wall of the precipitation well, the precipitation pipe comprises a well wall pipe and a filter pipe, filter holes are formed in the pipe wall of the filter pipe, the periphery of the filter pipe is covered with a filter screen, and a water pump located at the bottom of the precipitation pipe is arranged in the precipitation well during precipitation. And the dewatering well is filled with a plugging material after dewatering. Aiming at the construction structure, the construction method comprises the following steps: measuring a well position; burying a mouth protecting pipe; installing a drilling machine; drilling to form a hole; cleaning holes and changing slurry; a descending water pipe; filling a filter material; washing the well; carrying out rainfall trial operation; formal precipitation; and sealing the well. The precipitation well has the beneficial effects that the precipitation well is simple in structure, high in precipitation efficiency, high in adaptability and suitable for precipitation construction in a complex environment; the mouth protection pipe is embedded and cohesive soil outside the pipe is filled and sealed tightly, so that grout return outside the pipe during construction is effectively prevented; the dewatering well operates stably and reliably.

Description

Technical Field

[0001] The present application belongs to the technical field of municipal dewatering construction, is applied to the construction of municipal pipe jacking projects, and specifically relates to a municipal working well dewatering construction structure and a construction method. Background Art

[0002] With the acceleration of urbanization, municipal infrastructure construction is crucial to the development of cities. Among them, pipe jacking technology, as a commonly used construction method in municipal infrastructure construction, is widely used in the laying and repair of drainage, water supply, gas, electricity and other pipelines. However, during the pipe jacking construction process, the construction of the working well often faces many challenges, such as complex construction environment, high construction difficulty, high safety risks, etc., especially in some special geological conditions, such as when the groundwater at the location of individual working wells is large, it is difficult to ensure the construction quality of the working well structure without effective precipitation. Summary of the invention

[0003] The purpose of this application is to provide a municipal working well dewatering construction structure and construction method, which can efficiently dewater the working well, thereby ensuring the construction quality and construction safety of the jacking working well and solving the problem of dewatering the working well.

[0004] The purpose of this application is achieved through the following technical solutions:

[0005] A municipal working well dewatering construction structure comprises a dewatering well arranged at the periphery of the working well, a dewatering pipe is arranged in the dewatering well, filter material is arranged between the dewatering pipe and the well wall of the dewatering well, the dewatering pipe comprises an upper well wall pipe and a lower water filter pipe, filter holes are opened on the pipe wall of the water filter pipe, the periphery of the water filter pipe is covered with a filter screen, a water pump located at the bottom of the dewatering pipe is arranged in the dewatering well during dewatering, and the dewatering well is filled with sealing material after dewatering.

[0006] Furthermore, drainage wells are arranged on both sides of the working well.

[0007] Furthermore, the lower end of the well wall pipe is connected to the water filter pipe through a threaded sleeve.

[0008] Furthermore, the filter screen is a plurality of layers of nylon mesh cloth, and the filter screen is covered on the water filter pipe by means of iron wire wound on the downcomer pipe.

[0009] Furthermore, the filter material includes a lower crushed stone layer, a middle gravel and sand layer and an upper clay layer.

[0010] Furthermore, the sealing material comprises a lower cement sealing layer, a middle concrete layer and an upper cement mortar finishing layer, and the concrete layer comprises a lower primary concrete layer and an upper secondary concrete layer.

[0011] A municipal working well dewatering construction method, for the above-mentioned municipal working well dewatering construction structure, comprises the following steps: measuring and placing the well position; burying the mouth guard pipe: inserting the mouth guard pipe into the soil layer; installing the drilling rig: installing the drilling rig to the drilling operation position; drilling and forming a hole: the drilling rig drills the soil layer to form a dewatering well; cleaning the hole and changing the slurry: adding clean water to the borehole during the drilling process, and adjusting the mud viscosity until it meets the standard; a downpipe: lowering the downpipe into the dewatering well; filling filter material: filling filter material between the downpipe and the well wall of the downpipe; washing the well: using a water pump to pump and wash the gravel in the dewatering well; dewatering trial operation: installing a water pump in the dewatering well, and conducting a trial operation to dewater the well; formal dewatering: conducting formal operation to dewater the well; sealing the well: filling and sealing the dewatering well.

[0012] Further, the well position is measured and placed: the well position is measured and placed according to the well position plan layout diagram, and the well position is adjusted if obstacles are encountered during the on-site construction or affected by the construction conditions;

[0013] Buried mouth guard pipe: The bottom of the mouth guard pipe is inserted into the original soil layer, and the outside of the pipe is filled and sealed with clay to prevent slurry from returning outside the pipe during construction. The upper part of the mouth guard pipe is 0.1m to 0.3m above the ground;

[0014] Install the drilling rig: Install the drilling rig firmly and horizontally, with the big hook aligned with the center of the well hole, and the big hook, turntable and the center of the well hole forming a vertical line;

[0015] Drilling: When the drilling construction reaches the designed depth, drill 0.3-0.5m more; keep a good record of the drilling construction description. During the drilling process, if the actual geological conditions are found to be inconsistent with the data provided during the survey, the designer must be notified and the structure of the precipitation well must be adjusted to ensure that the placement of the filter pipe can be filled with water; when drilling the hole, tighten the large hook wire rope, press lightly and rotate slowly, and ensure that the drilling rig is level during the drilling process to ensure the verticality of the borehole; the hole construction adopts natural slurrying in the hole, and the mud density is controlled at 1.10-1.15 during the drilling process. When the drill tool is lifted or the work is stopped, the hole must be filled with mud to prevent the hole wall from collapsing;

[0016] Hole cleaning and slurry replacement: When the borehole reaches the top of the aquifer, water is added to adjust the slurry; after drilling to the designed elevation, the drill rod is lifted to 0.3-0.8m from the bottom of the hole before the drill is lifted, and the hole is punched to remove debris in the hole. At the same time, the slurry density in the hole is gradually adjusted to 1.03-1.07, and the sedimentation at the bottom of the hole is less than 30cm, and the returned slurry does not contain mud blocks;

[0017] Downfall pipe: After the downfall pipe is put into the site, check whether the filter holes of the water filter pipe meet the design requirements; measure the well depth before lowering the pipe. When the well depth meets the design requirements, start lowering the pipe, first lower the water filter pipe and then the well wall pipe. When lowering the pipe, set a set of centralizers at the upper and lower ends of the water filter pipe to ensure that the water filter pipe can be centered. After reaching the designed depth, the well wall pipe is fixed in the center at the wellhead; the process of lowering the water pipe is continuous and must not be stopped midway. If the hole collapses or the sediment is too thick, pull out the downfall pipe again, sweep and clean the hole, and then lower it again. It is strictly forbidden to force the downfall pipe into the collapsed bottom of the hole;

[0018] Filling filter material: Before filling the filter material, use a measuring rope to measure the depth inside and outside the downpipe. The difference between the two should not exceed the length of the sedimentation pipe. During the filling process, measure the height of the filter material as you fill it. Filling the filter material should be continuous and not be stopped midway until the filter material is lowered into the predetermined position. The final amount of filter material should not be less than 95% of the calculated amount. When using clay soil to seal the hole, in order to prevent the "bridging" phenomenon during the filling, the clay needs to be crushed before filling. During the filling, the speed and amount of the lowering should be controlled, and the filling should be carried out along the periphery of the well pipe according to the principle of less and slower filling, and then the sealing work should be done outside the wellhead pipe.

[0019] Well washing: Use the "pump into the bottom of the well to pump water" method to wash the well. After the well is completed, lower a deep well submersible pump to the bottom of the well to pump water. If there is sediment in the well, manually move the pump up and down while the pump is pumping water to disturb the sediment in the well and let the pump carry it out until the pump can reach the bottom of the well. After the water in the well is pumped out, pull out the pump to prevent fine particles from outside the well from entering the well and burying the pump. Repeat the above operation when the water level in the well rises to the upper end of the filter pipe. When there is no new sediment in the well and the water is clear, you can lower the submersible pump into the well.

[0020] Furthermore, dewatering trial operation: after each well is completed, a well is put into trial operation so that the dewatering well can be pumped out in time to ensure the water output of the well; before the trial operation, the elevation of each wellhead and the ground, the static water level, need to be measured, and then the trial operation is started to check whether the pumping equipment, pumping and drainage systems can meet the dewatering requirements; before installation, the pump body and control system should be checked to check the rotation direction of the motor, whether the connecting bolts of each part are tightened, whether the lubricating oil is sufficient, whether the seal of the cable joint is loose, and whether the cable is damaged, and then test run on the ground. If there is no problem, it can be put into use; the submersible motor, cable and joint have reliable insulation, and each pump is equipped with a control switch; the trial operation pumping time is controlled at 0.5 to 1.5 days, that is, each well is continuously pumped for 0.5 to 1.5 days after the completion of the well, in order to check the water quality and output;

[0021] Formal dewatering: The dewatering wells need to start pumping water 2 days before the excavation of the working wells to meet the pre-pumping time and ensure the dewatering effect. During the formal pumping, a water pump is installed in each dewatering well, and the water is pumped to the drainage ditch outside the foundation pit. The dewatering work is closely coordinated with the earthwork excavation construction. During the excavation process, the dewatering pipes are gradually cut off, and the pumping operation is restored in time. Attention is paid to the protection of the dewatering wells, and it is strictly forbidden to damage them by excavators. The dewatering depth is controlled according to the excavation depth and dewatering requirements of the foundation pit. Water is pumped on demand, and the water level is gradually lowered as the excavation progresses to control the impact on the external environment. Pumping requires people to be on duty all day and keep pumping records to grasp the pumping dynamics and guide the dewatering operation to achieve the optimal level.

[0022] Furthermore, seal the well: prepare sufficient cement and pre-mixed concrete before sealing the well; use a water pump to pump the water level in the well to the bottom of the well, and quickly remove the water pump; pour 0.8 to 1.2m of cement into the well, pour concrete to 0.8 to 1.2m below the bottom elevation of the bottom plate, and tamp the concrete; wait for the concrete to initially set, and observe the water seepage in the well, and pump out the remaining water again when water seeps; pour concrete for a second time to 8 to 12cm below the bottom of the bottom plate, and tamp the concrete; after the concrete has initially set, cut off the remaining well pipe to 8 to 12cm below the bottom plate; use cement mortar to level the wellhead, and the well is sealed.

[0023] Beneficial effects of this application:

[0024] (1) The precipitation well has a simple structure, high precipitation efficiency, and strong adaptability, and is suitable for precipitation construction in complex environments.

[0025] (2) The burial of the protective pipe and the filling and sealing of the sticky soil outside the pipe can effectively prevent the slurry from returning outside the pipe during construction.

[0026] (3) The operation of the precipitation well is stable and reliable.

[0027] (4) Suitable for dewatering construction in deeper soil layers.

[0028] (5) It can provide a working surface for the construction of the pipe jacking work pit in advance, which is conducive to saving construction time.

[0029] (6) The filtration of the tube well water filter operates well, effectively ensuring the precipitation amount and precipitation effect.

[0030] (7) Effectively ensure the sealing effect of the pipe well and prevent water seepage after the pipe well is sealed.

[0031] The aforementioned main scheme of the present application and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection in the present application; and in the present application, (non-conflicting options) can also be freely combined with each other and with other options. After understanding the scheme of the present application, those skilled in the art can understand that there are many combinations based on the prior art and common knowledge, all of which are technical schemes to be protected by the present application, and they are not exhaustively listed here. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the floor plan of this application.

[0033] Figure 2 It is a schematic diagram of the structural cross-section of the precipitation well of the present application.

[0034] Figure 3 It is a schematic diagram of the structural cross-section of the downcomer of the present application.

[0035] Figure 4 It is a schematic diagram of the main cross-sectional view of the sealing structure of the precipitation well of the present application.

[0036] Figure 5 It is a flowchart of this application.

[0037] In the figure: 1-working well, 2-drainage well, 3-drainage pipe, 4-well wall pipe, 5-water filter pipe, 6-threaded casing, 7-filter material, 8-crushed stone layer, 9-gravel and sand layer, 10-clay layer, 11-sealing material, 12-cement sealing bottom layer, 13-primary concrete layer, 14-secondary concrete layer, 15-cement mortar closing layer. DETAILED DESCRIPTION

[0038] The following non-limiting examples are provided to illustrate the present application.

[0039] Example 1

[0040] refer to Figure 1 to Figure 4 As shown, a municipal working well dewatering construction structure includes a working well 1, a dewatering well 2, a dewatering pipe 3, a well wall pipe 4, a water filter pipe 5, a filter screen, a threaded sleeve 6, a filter material 7, a crushed stone layer 8, a gravel and sand layer 9, a clay layer 10, a sealing material 11, a cement sealing layer 12, a primary concrete layer 13, a secondary concrete layer 14 and a cement mortar closing layer 15.

[0041] Working pit 1 is the working space for pipe jacking construction. Dewatering well 2 is arranged on the periphery of working pit 1. When dewatering well 2 is used, dewatering starts two days before the excavation of working pit 1 until the pipe jacking construction is completed. Dewatering well 2 is arranged 2m outside the edge of working pit 1. Dewatering well 2 is used to carry out dewatering operations around working pit 1 to ensure effective dewatering in the working pit and avoid affecting the quality of working pit structure construction.

[0042] Due to the large difference in ground elevation, the depth of the precipitation well 2 is based on the lowest point of the ground elevation of the working section. The well point with high terrain should increase the depth according to the ground elevation. The depth of the precipitation well is 7 to 13m, and the precipitation depth is controlled below 1m from the bottom of the foundation pit. The diameter of the precipitation well 2 hole is 600mm, and the inner diameter and outer diameter of the precipitation pipe 3 are 300mm and 360mm respectively. The wellhead of the precipitation well 2 (the precipitation pipe 3) should be higher than 0.3m above the ground and needs to be protected. It must not be damaged during excavation to prevent surface debris from falling into the well.

[0043] The precipitation well 2 is provided with a precipitation pipe 3 (diameter is ), the downcomer 3 includes a well wall pipe 4 at the upper section and a water filter pipe 5 at the lower section. The well wall pipe 4 is a 7.5m long steel pipe, and the well wall pipe 4 is a non-opening structure. The well wall pipe 4 can be divided into several sections, each section is 2.5m long, and three pipe sections are used for the 7.5m length (the number of pipe sections can be flexibly increased or decreased according to the length adjustment). The water filter pipe 5 is a 7.5m long steel pipe, and filter holes are opened on the pipe wall of the water filter pipe 5, specifically plum blossom holes are set. The well wall pipe 4 can be divided into several sections, each section is 2.5m long, and three pipe sections are used for the 7.5m length. When the well depth exceeds a certain height (8m), the lower end of the well wall pipe 4 is connected to the water filter pipe 5 through a threaded sleeve 6 (thread pitch 3mm) to achieve communication and fixed connection between the well wall pipe 4 and the water filter pipe 5.

[0044] The outer periphery of the filter pipe 5 is covered with a filter screen, and the filter screen and filter holes are used to filter the water. The filter screen is a plurality of layers of nylon mesh cloth, and the filter screen is covered on the filter pipe 5 by the iron wire wrapped on the downcomer 3, and the filter screen is used to achieve the filtering function. Specifically, the filter pipe 5 is covered with three layers of 60 mesh nylon mesh cloth, and is spirally wound with 18# iron wire @100 to ensure that the volume ratio of the sand content finally entering the downcomer 3 should be less than 1 / 100000.

[0045] A filter material 7 is provided between the downcomer 3 and the wall of the downcomer well 2, and the filter material 7 is used to filter groundwater. The filter material 7 includes a lower crushed stone layer 8, a middle gravel and sand layer 9, and an upper clay layer 10. The bottom 0.6 to 1.0 m is filled with crushed stone to form a crushed stone layer 8, and the crushed stone layer 8 is located at the bottom layer for padding. The gravel and sand layer 9 is located in the middle layer and is used for filtering and purifying groundwater. The gravel and sand specifications are 5 to 10 mm. When the gravel is filled to 1.5 to 2.5 m from the ground, clay is used to seal the hole. The clay layer 10 is located in the upper layer and is used to block the downcomer at the wellhead to prevent slurry from returning from the gap outside the pipe.

[0046] Groundwater is accumulated inside the downpipe 3. During precipitation, a water pump located at the bottom of the downpipe 3 is arranged in the downpipe well 2, and the water stored inside the downpipe is pumped out by the water pump to achieve underground precipitation. The water pump adopts a 100QJ5-24 / 6 deep well submersible pump with a head of 24m to pump water out, and the external drainage pipe adopts a plastic hose.

[0047] After the dewatering is completed, the dewatering well 2 is filled with a plugging material 11, which includes a lower cement sealing layer 12, a middle concrete layer and an upper cement mortar closing layer 15, and the concrete layer includes a lower primary concrete layer 13 and an upper secondary concrete layer 14.

[0048] Example 2

[0049] refer to Figure 1 to Figure 5 As shown, a municipal working well dewatering construction method, for the municipal working well dewatering construction structure of Example 1, includes three steps of dewatering well construction, dewatering well operation and well sealing.

[0050] The drilling machinery and equipment for the dewatering well construction are SW-100 engineering drilling rig and its supporting equipment. The drilling process of positive circulation rotary drilling mud wall protection, as well as the well wall pipe, water filter pipe, surrounding gravel filling, clay soil and other well-forming processes are adopted. The following steps are included:

[0051] Survey and place the well position: Survey and place the well position according to the well position plan diagram. If obstacles are encountered during on-site construction or the well position is affected by construction conditions, the well position shall be adjusted.

[0052] Bury the mouth guard pipe: insert the mouth guard pipe into the soil layer. The bottom of the mouth guard pipe is inserted into the original soil layer, and the outside of the pipe is filled and sealed with clay to prevent the slurry from returning outside the pipe during construction. The upper part of the mouth guard pipe is 0.1m to 0.3m above the ground.

[0053] Install the drilling rig: Install the drilling rig to the drilling operation location. The drilling rig should be installed firmly and horizontally, with the big hook aligned with the center of the well hole, and the big hook, turntable and the center of the well hole forming a vertical line.

[0054] Drilling: The drilling rig drills into the soil layer to form a drainage well. The diameter of the drainage well opening is When the drilling construction reaches the designed depth, drill 0.3 to 0.5 meters more. Keep good records of the drilling construction description. During the drilling process, if the actual geological conditions are found to be inconsistent with the data provided during the survey, the designer must be notified and the structure of the precipitation well must be adjusted to ensure that the placement of the filter pipe can be filled with water.

[0055] When drilling, tighten the big hook wire rope, press lightly and rotate slowly, and ensure the level of the drilling rig during drilling to ensure the verticality of the borehole. The hole construction adopts natural slurry in the hole. The mud density is controlled at 1.10-1.15 during the drilling process. When lifting the drill or stopping work, the hole must be filled with mud to prevent the hole wall from collapsing.

[0056] Hole cleaning and slurry replacement: Add clean water to the borehole during drilling to adjust the mud viscosity until it meets the standard. Hole cleaning and slurry replacement before the downcomer is a key process to ensure the quality of well completion. In order to ensure that the hole does not form too thick mud skin when entering the aquifer, clean water is added to adjust the slurry when the hole reaches the top of the aquifer. After drilling to the designed elevation, the drill rod is lifted to 0.3-0.8m from the bottom of the hole before lifting the drill, and the hole is punched to remove debris in the hole. At the same time, the mud density in the hole is gradually adjusted to 1.03-1.07, and the sedimentation at the bottom of the hole is less than 30cm, and the returned mud does not contain mud blocks.

[0057] The first hole cleaning and slurry replacement is the key to ensuring the quality of well completion, which will directly affect the quality of well completion. Therefore, if the hole cleaning and slurry replacement work does not meet the specified requirements (until there is no mud and sand), it is not allowed to enter the next construction process.

[0058] Downfall pipe: Lower the downfall pipe into the downfall well. After the downfall pipe is put into place, check whether the filter holes of the filter pipe meet the design requirements. The welding of the downfall pipe should be firm, vertical and impermeable. Measure the well depth before lowering the pipe. When the well depth meets the design requirements, start lowering the pipe, first lower the filter pipe and then the well wall pipe. When lowering the pipe, set a set of centralizers (with a diameter less than 5cm of the hole) at the upper and lower ends of the filter pipe to ensure that the filter pipe can be centered. After reaching the designed depth, the well wall pipe is fixed in the center at the wellhead. The process of lowering the water pipe is continuous and must not be stopped midway. If the hole collapses or the sediment is too thick, pull out the downfall pipe again, sweep and clean the hole, and then lower it again. It is strictly forbidden to force the downfall pipe into the collapsed bottom of the hole.

[0059] Filling filter material: Fill filter material between the downpipe and the wall of the downpipe. Before filling filter material, use a measuring rope to measure the depth inside and outside the downpipe. The difference between the two should not exceed the length of the sedimentation pipe. During the filling process, measure the height of the filter material. Filling filter material continuously and do not stop halfway until the filter material is lowered into the predetermined position. The final amount of filter material input should not be less than 95% of the calculated amount.

[0060] When using clay to seal the hole, in order to prevent the "bridging" phenomenon during the filling, the clay needs to be crushed (particle size less than 3cm) before filling. The speed and amount of filling should be controlled during the filling, and the filling should be carried out along the periphery of the well pipe according to the principle of less and slower filling, and then the sealing work should be done outside the wellhead pipe.

[0061] Well washing: Use a water pump to wash the gravel in the drainage well. The well washing adopts the "pump into the bottom of the well to pump water" method. After the well is completed, a deep well submersible pump is lowered to the bottom of the well to pump water. If there is sediment in the well, the water pump is pumped up and down by manpower to disturb the sediment in the well and let the water pump take it out until the water pump can reach the bottom of the well. After the water in the well is drained, pull out the water pump to prevent fine particles from outside the well from entering the well and burying the pump. When the water level in the well rises to the upper end of the filter pipe, repeat the above operation until there is no new sediment in the well and the water is clear, then the submersible pump can be lowered into the well. When the well is washed and the drainage is in operation, the water is drained to the municipal sewage pipe network around the site through pipes. The drainage pipes around the site are cleaned regularly to ensure the smooth flow of the drainage system.

[0062] The operation of the precipitation well is to lower the submersible pump, lay the drainage pipe, connect the cable, install the ground vacuum pump, etc. after the well construction is completed. After the pumping and drainage system is installed, you can start the test pumping. When setting up the cable and pipeline system, pay attention to avoid damage during the pumping process. Therefore, these equipment should be marked on site. The test pumping volume is greater than the designed water volume. Keep observation records of the pumping volume and water level. Check whether the pumping volume and water level drop values ​​are consistent with the design. If not, adjust the precipitation design plan in time. It includes the following steps:

[0063] Dewatering trial run: Install a water pump in the dewatering well and conduct a trial run to dewater the well. After each well is completed, a well will be put into trial run so that the dewatering well can be pumped out in time to ensure the water output of the well. Before the trial run, it is necessary to measure the elevation of each wellhead and the ground, the static water level, and then start the trial run to check whether the pumping equipment, pumping and drainage systems can meet the dewatering requirements. Before installation, the pump body and control system should be checked to check the rotation direction of the motor, whether the connecting bolts of each part are tightened, whether the lubricating oil is sufficient, whether the seal of the cable connector is loose, and whether the cable is damaged. Then, test run it on the ground. If there is no problem, it can be put into use. The submersible motor, cable and connector have reliable insulation, and each pump is equipped with a control switch. The trial run pumping time is controlled at 0.5 to 1.5 days, that is, each well is continuously pumped for 0.5 to 1.5 days after the completion of the well to check the water quality and output;

[0064] Formal dewatering: Formal operation to dewater the well. The dewatering well needs to start pumping water 2 days before the excavation of the working well to meet the pre-pumping time and ensure the dewatering effect. During the formal pumping, a water pump is installed in each dewatering well, and the water is pumped to the drainage ditch outside the foundation pit. When pumping water, the groundwater is abundant and the water output of the pump is large. As time goes by, the water output of a single well will gradually decrease.

[0065] The dewatering work is closely coordinated with the earthwork excavation construction. During the excavation process, the dewatering pipes are gradually cut off, and the pumping operation is resumed in time. Attention should be paid to the protection of the dewatering wells, and excavator damage is strictly prohibited. According to the actual situation on site, the dewatering depth is controlled according to the excavation depth and the requirements of the dewatering depth of the foundation pit. Water is pumped on demand, and the water level is gradually lowered with the excavation to control the impact on the surrounding environment. The site is currently pumping water in three stages, and professional construction workers are assigned to be responsible for inspection and record keeping; the first stage of earthwork is excavated to 1 / 2 of the foundation pit depth, and the water level drops to -2.6m; the second stage is excavated to the bottom of the foundation pit, and the water level drops to -0.5m at the bottom of the foundation pit. Pumping requires people to be on duty all day and keep pumping records to grasp the pumping dynamics and guide the dewatering operation to achieve the best.

[0066] Well sealing: Fill and seal the precipitation well. The precipitation well pipe can be cut off as the construction progresses on the working well floor. Prepare enough cement and premix enough C15 concrete before sealing the well. Use a pump to pump the water level in the well to the bottom of the well, and quickly remove the pump. Pour 0.8-1.2m high cement into the well, pour concrete to 0.8-1.2m below the bottom elevation of the floor, and tamp the concrete; wait for the initial setting of the concrete, and observe the water seepage in the well. Pump out the remaining water again when water seeps. Pour the concrete for the second time to 8-12cm below the bottom of the floor, and tamp the concrete. After the initial setting of the concrete, cut off the remaining well pipe to 8-12cm below the floor; use cement mortar to level the wellhead, and the well is sealed.

[0067] The aforementioned basic examples and their further selected examples can be freely combined to form multiple embodiments, all of which are embodiments that can be adopted and claimed for protection in this application. In the scheme of this application, each selected example can be arbitrarily combined with any other basic examples and selected examples.

[0068] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A municipal working well dewatering construction structure, comprising a dewatering well (2) arranged on the periphery of a working well (1), characterized in that: The precipitation well (2) is provided with a precipitation pipe (3), a filter material (7) is provided between the precipitation pipe (3) and the well wall of the precipitation well (2), the precipitation pipe (3) comprises an upper well wall pipe (4) and a lower water filter pipe (5), filter holes are provided on the pipe wall of the water filter pipe (5), and the outer periphery of the water filter pipe (5) is covered with a filter screen. During precipitation, a water pump located at the bottom of the precipitation pipe (3) is arranged in the precipitation well (2), and a plugging material (11) is filled in the precipitation well (2) after precipitation.

2. The municipal working well dewatering construction structure according to claim 1 is characterized by: Drainage wells (2) are arranged on both sides of the working well (1).

3. The municipal working well dewatering construction structure according to claim 1 is characterized by: The lower end of the well wall pipe (4) is connected to the water filter pipe (5) through a threaded sleeve (6).

4. The municipal working well dewatering construction structure according to claim 1 or 3, characterized in that: The filter screen is a plurality of layers of nylon mesh cloth, and the filter screen is covered on the water filter pipe (5) through the iron wire wound on the downcomer pipe (3).

5. The municipal working well dewatering construction structure according to claim 1 is characterized by: The filter material (7) comprises a lower crushed stone layer (8), a middle gravel sand layer (9) and an upper clay layer (10).

6. The municipal working well dewatering construction structure according to claim 1 or 5, characterized in that: The sealing material (11) comprises a lower cement sealing layer (12), a middle concrete layer and an upper cement mortar closing layer (15), wherein the concrete layer comprises a lower primary concrete layer (13) and an upper secondary concrete layer (14).

7. A method for dewatering a municipal working well, for the dewatering construction structure for a municipal working well according to any one of claims 1 to 6, characterized in that: The steps include: Survey and place well positions; Bury the protective pipe: insert the protective pipe into the soil layer; Install the drilling rig: install the drilling rig to the drilling operation location; Drilling: The drilling rig drills into the soil to form a precipitation well; Hole cleaning and slurry replacement: Add clean water into the borehole during drilling to adjust the slurry viscosity until it reaches the standard; Downcomer pipe: put downcomer pipe in the downcomer well; Filling filter material: Fill filter material between the downpipe and the wall of the downpipe; Well washing: Use a water pump to wash out the gravel in the well; Dewatering trial run: Install a water pump in the dewatering well and conduct a trial run to dewater the well; Formal dewatering: Formal operation to dewater the well; Well sealing: Fill and seal the precipitation well.

8. The municipal working well dewatering construction method according to claim 7, characterized in that: Well location measurement: well location measurement is carried out according to the well location plan layout diagram. If obstacles are encountered during on-site construction or the well location is affected by construction conditions, the well location will be adjusted; Buried mouth guard pipe: The bottom of the mouth guard pipe is inserted into the original soil layer, and the outside of the pipe is filled and sealed with clay to prevent slurry from returning outside the pipe during construction. The upper part of the mouth guard pipe is 0.1m to 0.3m above the ground; Install the drilling rig: Install the drilling rig firmly and horizontally, with the big hook aligned with the center of the well hole, and the big hook, turntable and the center of the well hole forming a vertical line; Drilling: When the drilling construction reaches the designed depth, drill 0.3-0.5m more; keep a good record of the drilling construction description. During the drilling process, if the actual geological conditions are found to be inconsistent with the data provided during the survey, the designer must be notified and the structure of the precipitation well must be adjusted to ensure that the placement of the filter pipe can be filled with water; when drilling the hole, tighten the large hook wire rope, press lightly and rotate slowly, and ensure that the drilling rig is level during the drilling process to ensure the verticality of the borehole; the hole construction adopts natural slurrying in the hole, and the mud density is controlled at 1.10-1.15 during the drilling process. When the drill tool is lifted or the work is stopped, the hole must be filled with mud to prevent the hole wall from collapsing; Hole cleaning and slurry replacement: When the borehole reaches the top of the aquifer, water is added to adjust the slurry; after drilling to the designed elevation, the drill rod is lifted to 0.3-0.8m from the bottom of the hole before the drill is lifted, and the hole is punched to remove debris in the hole. At the same time, the slurry density in the hole is gradually adjusted to 1.03-1.07, and the sedimentation at the bottom of the hole is less than 30cm, and the returned slurry does not contain mud blocks; Downfall pipe: After the downfall pipe is put into the site, check whether the filter holes of the filter pipe meet the design requirements; measure the well depth before lowering the pipe. When the well depth meets the design requirements, start lowering the pipe, first lower the filter pipe and then the well wall pipe. When lowering the pipe, set a set of centralizers at the upper and lower ends of the filter pipe to ensure that the filter pipe can be centered. After lowering to the designed depth, the well wall pipe is fixed in the center at the wellhead; The process of downpipe shall be carried out continuously and shall not be stopped midway. If the hole collapses or the sediment is too thick, the downpipe shall be pulled out again, and the hole shall be swept and cleaned before being put back in again. It is strictly forbidden to force the downpipe into the bottom of the collapsed hole; Filling filter material: Before filling the filter material, use a measuring rope to measure the depth inside and outside the downcomer pipe. The difference between the two should not exceed the length of the sedimentation pipe. During the filling process, measure the height of the filter material as you fill it. Filling the filter material should be continuous and not be stopped until the filter material is lowered into the predetermined position. The final amount of filter material should not be less than 95% of the calculated amount. When using clay soil to seal the hole, in order to prevent the "bridging" phenomenon during the filling, the clay needs to be crushed before filling. During the filling, the speed and amount of the lowering should be controlled, and the filling should be carried out along the periphery of the well pipe according to the principle of less and slower filling, and then the sealing work should be done outside the wellhead pipe. Well washing: Use the "pump into the bottom of the well to pump water" method to wash the well. After the well is completed, lower a deep well submersible pump to the bottom of the well to pump water. If there is sediment in the well, the water pump is manually moved up and down while it is pumping water to disturb the sediment in the well and let the water pump carry it out until the water pump can reach the bottom of the well; after the water in the well is drained, pull out the water pump to prevent fine particles from outside the well from entering the well and burying the pump. Repeat the above operation when the water level in the well rises to the upper end of the filter pipe. When there is no new sediment in the well and the water is clear, the submersible pump can be lowered into the well cover.

9. The municipal working well dewatering construction method according to claim 7, characterized in that: Dewatering trial operation: After each well is completed, a well is put into trial operation so that the dewatering well can be pumped out in time to ensure the water output of the well. Before the trial operation, the elevation of each wellhead and the ground, the static water level, must be measured, and then the trial operation is started to check whether the pumping equipment, pumping and drainage systems can meet the dewatering requirements. Before installation, the pump body and control system should be checked to check the rotation direction of the motor, whether the connecting bolts of each part are tightened, whether the lubricating oil is sufficient, whether the seal of the cable connector is loose, and whether the cable is damaged. Then, a trial run should be conducted on the ground. If there is no problem, it can be put into use. The submersible motor, cable and connector have reliable insulation, and each pump is equipped with a control switch. The trial operation pumping time is controlled at 0.5 to 1.5 days, that is, each well is continuously pumped for 0.5 to 1.5 days after the completion of the well, in order to check the water quality and output. Formal dewatering: The dewatering wells need to start pumping water 2 days before the excavation of the working wells to meet the pre-pumping time and ensure the dewatering effect. During the formal pumping, a water pump is installed in each dewatering well, and the water is pumped to the drainage ditch outside the foundation pit. The dewatering work is closely coordinated with the earthwork excavation construction. During the excavation process, the dewatering pipes are gradually cut off, and the pumping operation is restored in time. Attention is paid to the protection of the dewatering wells, and it is strictly forbidden to damage them by excavators. The dewatering depth is controlled according to the excavation depth and dewatering requirements of the foundation pit. Water is pumped on demand, and the water level is gradually lowered as the excavation progresses to control the impact on the external environment. Pumping requires people to be on duty all day and keep pumping records to grasp the pumping dynamics and guide the dewatering operation to achieve the optimal level.

10. The municipal working well dewatering construction method according to claim 7, characterized in that: Well sealing: Prepare sufficient cement and pre-mixed concrete before sealing the well; use a water pump to pump the water level in the well to the bottom of the well, and quickly remove the water pump; pour 0.8 to 1.2m of cement into the well, pour concrete to 0.8 to 1.2m below the bottom elevation of the bottom plate, and tamp the concrete; wait for the concrete to initially set, and observe the water seepage in the well. When water seeps, pump out the remaining water again; pour concrete a second time to 8 to 12cm below the bottom of the bottom plate, and tamp the concrete; after the concrete has initially set, cut off the remaining well pipe to 8 to 12cm below the bottom plate; use cement mortar to level the wellhead, and the well is sealed.

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