Positive and negative pressure combined dewatering structure for long and narrow foundation pit of reclamation stratum and construction method

Abstract

The invention discloses a positive and negative pressure combined dewatering structure for a long and narrow foundation pit of a reclamation stratum and a construction method, and relates to the technical field of foundation pit construction, the positive and negative pressure combined dewatering structure comprises a to-be-constructed foundation pit and deep soil located below the to-be-constructed foundation pit, and a waterproof curtain is arranged in the circumferential direction of the to-be-constructed foundation pit and vertically penetrates through the to-be-constructed foundation pit to be inserted into the deep soil; a plurality of sets of positive pressure precipitation mechanisms are arranged in the foundation pit to be constructed, a plurality of sets of negative pressure precipitation mechanisms are arranged among the multiple sets of positive pressure precipitation mechanisms, each set of positive pressure precipitation mechanism and the corresponding negative pressure precipitation mechanism are alternately arranged, and through cooperation of the positive pressure precipitation mechanisms and the negative pressure precipitation mechanisms, the precipitation work efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of foundation pit construction, and in particular to a positive and negative pressure combined dewatering structure and a construction method for a narrow and long foundation pit in a reclamation stratum. Background Art

[0002] Before foundation pit construction, precipitation work is usually required to ensure that the foundation pit can be constructed under dry conditions. Especially when foundation pit construction is carried out in reclaimed strata, precipitation work is generally required due to the high water content of the reclaimed strata. Common precipitation methods are mainly positive pressure precipitation and negative pressure precipitation. During construction, usually only one precipitation method can be selected.

[0003] With regard to the above-mentioned related technologies, the existing precipitation methods generally require a period of two to three months to meet the requirements. When carrying out projects with urgent construction periods, the efficiency of precipitation work is insufficient, which may cause delays in the construction period. Summary of the invention

[0004] The first purpose of the present application is to provide a positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum, so as to improve the problem of low efficiency of existing dewatering methods.

[0005] The present application provides a positive and negative pressure combined dewatering structure and construction method for a narrow and long foundation pit in a reclamation stratum, which adopts the following technical solutions: A positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclaimed stratum comprises a foundation pit to be constructed and a deep soil layer below the foundation pit to be constructed, wherein a water-stop curtain is arranged circumferentially of the foundation pit to be constructed, and the water-stop curtain vertically penetrates the foundation pit to be constructed and is inserted into the deep soil layer; a plurality of groups of positive pressure dewatering mechanisms are arranged in the foundation pit to be constructed, and a plurality of groups of negative pressure dewatering mechanisms are arranged between the plurality of groups of the positive pressure dewatering mechanisms, and each group of the positive pressure dewatering mechanisms and the negative pressure dewatering mechanisms are arranged alternately.

[0006] By adopting the above technical scheme, water-stop curtains are circumferentially arranged around the foundation pit to be constructed, and the insertion depth of the water-stop curtains needs to exceed the depth of the foundation pit to be constructed; the water-stop curtains can isolate the foundation pit to be constructed from the aquifer outside the foundation pit, creating a relatively independent precipitation working space, and preventing groundwater outside the foundation pit from flowing into the foundation pit, resulting in failure of precipitation in the foundation pit; several groups of positive pressure precipitation mechanisms are arranged in the foundation pit to be constructed, and several groups of negative pressure precipitation mechanisms are arranged between each group of positive pressure precipitation mechanisms. The positive pressure precipitation mechanisms and the negative pressure precipitation mechanisms are alternately arranged, and precipitation work is carried out through the cooperation of the positive pressure precipitation mechanisms and the negative pressure precipitation mechanisms, thereby effectively improving the efficiency of precipitation work.

[0007] Preferably, the negative pressure dewatering mechanism includes a drain plate and a drain pipe, and a group of the negative pressure dewatering mechanism is provided with a plurality of drain plates and a drain pipe; one end of the drain plate is vertically inserted in the foundation pit to be constructed, and the other end of the drain plate is located outside the foundation pit to be constructed, and the part of the drain plate located outside the foundation pit to be constructed is covered with a sand layer; one end of the drain pipe is arranged in the sand layer, and the other end is provided with a pumping device; a water-proof membrane is arranged on the upper surface of the foundation pit to be constructed, and a plurality of fixing bolts are arranged between the water-proof membrane and the surface of the foundation pit to be constructed.

[0008] By adopting the above technical scheme, the negative pressure dewatering mechanism is interspersed between the positive pressure dewatering mechanisms, one end of the drainage board is inserted into the foundation pit to be constructed, and the other end is left outside the foundation pit to be constructed, and the drainage board can guide the moisture in the foundation pit to be constructed to the outside of the foundation pit through the drainage board; the drainage board located outside the foundation pit to be constructed is covered with a sand layer, and the moisture guided out through the drainage board will be absorbed by the sand layer, and the guided moisture will be collected by the sand layer; at the same time, one end of the drainage pipe is buried in the sand layer, and a pumping device is installed at the other end to pump out the moisture in the sand layer through the drainage pipe; at the same time, the surface of the entire foundation pit to be constructed is covered with a waterproof membrane, so that a relatively closed space is formed in the foundation pit to be constructed, so that a pressure difference can be formed inside and outside the foundation pit to be constructed during the precipitation process, thereby improving the drainage efficiency of the drainage board; the waterproof membrane is fixed to the surface of the foundation pit to be constructed using fixing bolts to prevent the waterproof membrane from being opened due to unstable fixing and becoming ineffective.

[0009] Preferably, a guide plate is provided at one end of the drainage board inserted into the foundation pit to be constructed.

[0010] By adopting the above technical solution, since the drainage board is made of flexible material, it is inconvenient to insert it into the foundation pit to be constructed, and it is easy to deform and overlap, which affects the water absorption efficiency of the drainage board. Therefore, a guide plate is installed at one end of the drainage board inserted into the foundation pit to be constructed. The guide plate can be used to fully open the drainage board and relatively easily insert it into the foundation pit to be constructed, thereby improving the installation and drainage efficiency of the drainage board.

[0011] Preferably, a guide chamfer is provided at one end of the guide plate close to the deep soil.

[0012] By adopting the above technical solution, a guide chamfer is provided at one end of the guide plate, and the guide chamfer can be used to make it easier to insert the drainage board into the foundation pit to be constructed, thereby improving the installation efficiency of the drainage board.

[0013] Preferably, the positive pressure dewatering mechanism includes a dewatering blind well and a well pipe inserted in the dewatering blind well, the dewatering blind well passes through the foundation pit to be constructed to the deep soil; the side wall of the well pipe is provided with a plurality of water inlet holes, a pumping pipe is provided in the well pipe, a submersible pump is provided at one end of the pumping pipe inserted into the well pipe, and the other end of the pumping pipe is located outside the foundation pit to be constructed; a filtering mechanism is provided in the well pipe.

[0014] By adopting the above technical scheme, since the negative pressure dewatering mechanism needs to use a waterproof membrane to create a pressure difference, a blind well must be used in the positive pressure dewatering mechanism, and the pressure difference created by the negative pressure dewatering mechanism can also improve the water absorption efficiency of the positive pressure dewatering mechanism; the dewatering blind well needs to extend from the foundation pit to be constructed to the deep soil, in order to be able to lower the water level in the foundation pit to be constructed below the foundation pit, so as to ensure the dryness of the construction part of the foundation pit; the well pipe is arranged in the dewatering blind well, and the side wall of the well pipe is provided with a plurality of water inlet holes, and the water in the foundation pit is collected in the well pipe through the water inlet holes; a pumping pipe is arranged in the well pipe, and a submersible pump is installed at one end of the pumping pipe, and the water collected in the well pipe is pumped out of the foundation pit by the submersible pump; a filtering mechanism is arranged in the well pipe, which is used to filter the soil when collecting the water in the foundation pit to prevent impurities such as soil from affecting the pumping efficiency.

[0015] Preferably, several of the positive pressure dewatering mechanisms in the same row form a group, a conduit is provided at one end of the pumping pipe in one group of the positive pressure dewatering mechanisms away from the submersible pump, the conduits in one group are interconnected, and a pumping device 2 is provided at one end of the conduit away from the pumping pipe.

[0016] By adopting the above technical solution, a manifold is used to connect the pumping pipes of the same group, and a pumping device 2 is installed at one end of the manifold, so that water in a group of positive pressure precipitation mechanisms can be pumped out at the same time, saving resources while also improving installation efficiency.

[0017] Preferably, the filtering mechanism includes filter plate 1 and filter plate 2, wherein filter plate 1 is arranged in the water inlet hole, and filter plate 2 is arranged in the well pipe close to one side of the submersible pump, and filter plate 2 is provided with a mounting hole for a water pump to pass through.

[0018] By adopting the above technical solution, the filter plate 1 arranged in the water inlet hole first performs the first filtration, and the filter plate 2 is installed at one end of the well pipe close to the submersible pump for the second filtration. Impurities are filtered out through the filtering mechanism to improve the pumping efficiency of the submersible pump; the installation hole is provided to enable the filter plate 2 to pass when the pumping pipe is installed.

[0019] The second purpose of the present application is to provide a construction method for a positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum, so as to improve the problem of low efficiency of existing dewatering methods.

[0020] A construction method for a positive and negative pressure combined dewatering structure of a narrow and long foundation pit in a reclamation stratum: Preferably, S100, a water-stop curtain is inserted around the foundation pit to be constructed, and the water-stop curtain is inserted through the foundation pit to be processed into the deep soil; S200, several positive pressure dewatering mechanisms are set up in the foundation pit to be constructed, and several positive pressure dewatering mechanisms in the same row are a group; one end of the pumping pipe is installed together with the submersible pump, and then the end of the pumping pipe installed with the submersible pump is placed in the positive pressure dewatering mechanism; then the pumping pipes of the same group are connected using a manifold, and the manifold is connected to the second pumping device.

[0021] S300, a plurality of groups of negative pressure dewatering mechanisms are arranged in the foundation pit to be constructed, wherein the negative pressure dewatering mechanisms are located between every two groups of positive pressure dewatering mechanisms, that is, the positive pressure dewatering mechanisms and the negative pressure dewatering mechanisms are arranged alternately, and the negative pressure dewatering mechanisms are connected to a pumping device; at the same time, a waterproof membrane is laid on the foundation pit to be constructed, and the waterproof membrane is fixed with fixing bolts; S400, start the first pumping device and the second pumping device to discharge the water discharged from the foundation pit to be constructed to the outside of the foundation pit to be constructed through the first pumping device and the second pumping device.

[0022] By adopting the above technical scheme, the foundation pit to be constructed is separated from other soil layers by a water-stop curtain to prevent moisture in other soil layers from flowing into the foundation pit to be constructed; then, several groups of positive-pressure dewatering mechanisms and negative-pressure dewatering mechanisms are alternately arranged in the foundation pit to be constructed, which can complete the dewatering work more efficiently than the existing single dewatering method; the manifold discharges the moisture derived from a group of positive-pressure dewatering mechanisms out of the foundation pit to be constructed through a second pumping device; the negative-pressure dewatering mechanism discharges the moisture out of the foundation pit to be constructed through a first pumping device connected thereto.

[0023] Preferably, S210, the positive pressure dewatering mechanism includes a dewatering blind well and a well pipe inserted in the dewatering blind well. First, a dewatering blind well body that penetrates the foundation pit to be constructed to the deep soil is excavated, and then a filter device is installed in the well pipe, and the well pipe is placed in the dewatering blind well. Subsequently, one end of the pumping pipe equipped with a submersible pump is placed in the well pipe, and at the same time, when the other end of the pumping pipe extends out of the dewatering blind well, the dewatering blind well is sealed with a soil layer, and at this time, the pumping pipes of the same group are connected to the confluence pipe; S211, the filtering mechanism includes filter plate 1 and filter plate 2, and filter plate 1 is arranged in the water inlet hole of the side wall of the well pipe; before installing filter plate 2, firstly pass the suction pipe of the submersible pump which has not been installed yet through the installation hole on filter plate 2, then install the submersible pump, and then put the submersible pump together with filter plate 2 into the well pipe.

[0024] By adopting the above technical scheme, the positive pressure dewatering mechanism includes a dewatering blind well and a well pipe. The dewatering blind well needs to pass through the foundation pit to be constructed to the deep soil to ensure that the water level in the foundation pit to be constructed can be lowered to below the foundation pit; before placing the well pipe, the filter plate 1 is installed in the water inlet hole and then placed, and then the suction pipe is passed through the installation hole on the filter plate 2, and then the submersible pump is connected to the suction pipe passing through the installation hole, and the submersible pump and the filter plate 2 are placed in the well pipe together, and the filter plate 1 is used for preliminary filtration, and the filter plate 2 is used for secondary filtration, so that the collected water is mixed with as little impurities as possible, thereby improving the pumping efficiency of the submersible pump.

[0025] Preferably, S310, the negative pressure dewatering mechanism includes a drainage board and a drainage pipe, a guide plate is installed at one end of the drainage board that needs to be inserted into the foundation pit to be constructed, and then a plate inserting machine is used to insert the drainage board into the foundation pit to be constructed through the guide plate, and the other end of the drainage board is left outside the foundation pit to be constructed, and then a group of drainage boards left outside the foundation pit to be constructed are covered with a sand layer, and the drainage pipe is also buried in the sand layer, and the drainage pipe is then connected to a pumping device; S311, a guide chamfer is provided at one end of the guide plate close to the deep soil.

[0026] By adopting the above technical scheme, the negative pressure dewatering mechanism uses the drainage board to guide the moisture in the foundation pit to be constructed into the sand layer, and then discharges the moisture in the sand layer out of the foundation pit to be constructed through the drainage pipe; because the drainage board may be deformed and overlapped when inserted into the foundation pit to be constructed, affecting the dewatering efficiency of the drainage board, a guide plate is installed at one end of the drainage board inserted into the foundation pit to be constructed, and a guide chamfer is provided at the end of the guide plate close to the deep soil. The guide plate is used to fully unfold the drainage board and can be inserted into the foundation pit to be constructed relatively more easily.

[0027] In summary, the present application includes at least one of the following beneficial technical effects: 1. In the foundation pit to be constructed with a water-stop curtain set in the circumferential direction, the positive pressure dewatering mechanism and the negative pressure dewatering mechanism are used to cooperate with each other to carry out dewatering work, which effectively improves the efficiency of foundation pit dewatering; 2. On the drain board in the negative pressure precipitation mechanism, a guide plate is installed at the end where the drain board is inserted into the construction area. The guide plate is used to fully unfold the drain board so that the drain board is not easily deformed or overlapped. At the same time, a guide chamfer is provided at the end of the guide board close to the deep soil, so that the insertion of the drain board is relatively easier; 3. A filtering mechanism is provided in the positive pressure dewatering mechanism, including filter plate 1 and filter plate 2, wherein filter plate 1 is installed in the water inlet hole for primary filtration; filter plate 2 is arranged in the well pipe at one end close to the submersible pump for secondary filtration; most of the impurities are filtered out by the filtering mechanism, thereby improving the pumping efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1The overall structural diagram of a positive and negative pressure combined dewatering structure of a narrow foundation pit in reclamation strata.

[0029] Figure 2 yes Figure 1 Enlarged view of part A in .

[0030] Figure 3 yes Figure 1 Enlarged view of part B in .

[0031] Figure 4 It is a cross-sectional schematic diagram for showing the internal structure of the negative pressure precipitation mechanism in the embodiment.

[0032] Figure 5 It is a cross-sectional schematic diagram for showing the internal structure of the positive pressure dewatering mechanism in the embodiment.

[0033] In the figure, 1. foundation pit to be constructed; 2. deep soil; 3. water-stop curtain; 4. positive pressure dewatering mechanism; 41. dewatering blind well; 42. well pipe; 421. water inlet hole; 43. pumping pipe; 44. submersible pump; 45. conduit; 46. pumping device 2; 5. negative pressure dewatering mechanism; 51. drainage board; 511. guide plate; 5111. guide chamfer; 52. drainage pipe; 53. sand layer; 54. pumping device 1; 55. water-proof membrane; 56. fixing bolt; 6. filtering mechanism; 61. filter plate 1; 62. filter plate 2; 621. installation hole; 7. soil layer outside the foundation pit. DETAILED DESCRIPTION

[0034] The following is combined with Figure 1 -Attached Figure 5 , further details of this application are given.

[0035] Embodiment 1: A positive and negative pressure combined dewatering structure for a narrow and long foundation pit in reclamation stratum, referring to Figure 1 , including a foundation pit 1 to be constructed and a deep soil 2 located below the foundation pit 1 to be constructed. Within the scope of the foundation pit 1 to be constructed, water-stop curtains 3 are installed circumferentially around the periphery, and the water-stop curtains 3 penetrate the foundation pit 1 to be constructed and are inserted into the deep soil 2. The water-stop curtains 3 are used to separate the foundation pit 1 to be constructed from the soil layer 7 outside the foundation pit to prevent water from the soil layer 7 outside the foundation pit from flowing into the foundation pit 1 to be constructed after the foundation pit 1 is dewatered; the water-stop curtains 3 are penetrated into the deep soil 2 to ensure that the water level is maintained below the foundation pit 1 to be constructed after dewatering; a plurality of groups of positive-pressure dewatering mechanisms 4 and negative-pressure dewatering mechanisms 5 are alternately arranged in the foundation pit 1 to be constructed.

[0036] Reference Figure 1 and Figure 4The negative pressure precipitation mechanism 5 includes a drainage plate 51 and a drainage pipe 52. A set of negative pressure precipitation mechanisms 5 includes two rows of drainage plates 51 and a drainage pipe 52. The drainage plate 51 is inserted into the foundation pit 1 to be constructed to guide the water to the outside of the foundation pit 1 to be constructed. At the same time, in order to avoid deformation and overlapping of the drainage plate 51 when inserted into the foundation pit 1 to be constructed, thereby affecting the precipitation efficiency, a guide plate 511 is installed at one end of the drainage plate 51 inserted into the foundation pit 1 to be constructed. The drainage plate 51 is fully unfolded by using the guide plate 511, and is conveniently inserted into the foundation pit 1 to be constructed; a guide chamfer 5111 is provided at one end of the guide plate 511 close to the deep soil 2, and the guide chamfer 5111 can make the installation of the drainage plate 51 easier; after the drainage plate 51 is inserted into the foundation pit 1 to be constructed, the other end will be exposed outside the foundation pit 1 to be constructed, and at this time, the sand layer 53 is used to drain the water in the foundation pit 1 to be constructed. The drainage board 51 outside the construction foundation pit 1 is covered, and the dry sand layer 53 will absorb the moisture discharged from the drainage board 51; while covering the drainage board 51, the drainage pipe 52 is also buried in the sand layer 53, and the end of the drainage pipe 52 away from the sand layer 53 is connected to a pumping device 54, and the pumping device 54 is a water pump, and the water in the sand layer 53 is discharged through the drainage pipe 52 by the pumping device 54; at the same time, the surface of the foundation pit 1 to be constructed is covered with a waterproof membrane 55, so that a relatively closed space is formed in the foundation pit 1 to be constructed. When the drainage board 51 and the drainage pipe 52 are used for precipitation work, a pressure difference will be generated inside and outside the foundation pit 1 to be constructed, thereby exerting pressure on the drainage board 51 to improve the precipitation efficiency; the waterproof membrane 55 is fixed to the surface of the foundation pit 1 to be constructed using fixing bolts 56 to prevent the waterproof membrane 55 from being fixed insufficiently and detaching from the surface of the foundation pit 1 to be constructed.

[0037] Reference Figure 1 and Figure 5 The positive pressure dewatering mechanism 4 includes a dewatering blind well 41 and a well pipe 42. Multiple positive pressure dewatering mechanisms 4 in the same row are a group. The reason for selecting a blind well is that the negative pressure dewatering mechanism 5 needs to use a waterproof membrane 55 to create a pressure difference. The use of the dewatering blind well 41 does not affect the effect of the waterproof membrane 55. At the same time, the pressure difference created by the waterproof membrane 55 can also improve the dewatering efficiency of the positive pressure dewatering mechanism 4. In order to ensure that the water level after dewatering is lower than the foundation pit 1 to be constructed, the dewatering blind well 41 needs to extend from the foundation pit 1 to be constructed to the deep soil 2. The well pipe 42 is arranged in a manner that fits the dewatering blind well 41 and is arranged in the dewatering blind well. In the blind well 41, a plurality of water inlet holes 421 are provided on the side wall of the well pipe 42, and the water in the foundation pit 1 to be constructed is collected in the well pipe 42 through the water inlet holes 421; a pumping pipe 43 is installed in the well pipe 42, and a submersible pump 44 is installed at one end of the pumping pipe 43 inserted into the well pipe 42, and the water collected in the well pipe 42 is pumped out of the well pipe 42 through the pumping pipe 43 by the submersible pump 44, and discharged outside the foundation pit 1 to be constructed; a filtering mechanism 6 is also provided in the well pipe 42 to reduce impurities entering the well pipe 42 and reduce the influence of impurities on the pumping efficiency.

[0038] Reference Figure 5 In a group of positive pressure dewatering mechanisms 4, one end of the water pumping pipe 43 away from the submersible pump 44 is connected together using a manifold 45. At the same time, one end of the manifold 45 away from the water pumping pipe 43 is connected to a water pumping device 2 46. The water pumping device 2 46 is a water pump, which can discharge water from a group of positive pressure dewatering mechanisms 4 at the same time, improve the installation efficiency of the mechanism, and save construction resources.

[0039] Reference Figure 2 and Figure 3 The filtering mechanism 6 arranged in the well pipe 42 includes filter plate 1 and filter plate 2. Filter plate 1 is installed in the water inlet for preliminary filtration; filter plate 2 is installed on the side of the well pipe 42 close to the submersible pump 44. A mounting hole 621 for the pumping pipe 43 to pass through is provided on filter plate 2 to facilitate the installation of filter plate 2. Filter plate 2 performs secondary filtration to further reduce the mud and sand impurities in the water, thereby improving the pumping efficiency of the submersible pump 44.

[0040] The implementation principle of the embodiment of the present application is: First, use the water-stop curtain 3 to separate the foundation pit 1 to be constructed from the soil layer 7 outside the foundation pit. The water-stop curtain 3 needs to penetrate the foundation pit 1 to be constructed and be inserted into the deep soil 2. Then set up a positive pressure dewatering mechanism 4. The positive pressure dewatering mechanism 4 includes a dewatering blind well 41 and a well pipe 42. The dewatering blind well 41 needs to pass through the foundation pit 1 to be constructed to the deep soil 2 to ensure that the water level after dewatering is below the foundation pit 1 to be constructed. A filtering mechanism 6 is set in the well pipe 42. The filtering mechanism 6 includes a filter plate 1 and a filter plate 2. The filter plate 1 is installed in the water inlet hole 421 of the well pipe 42. There is a water pumping pipe on the filter plate 2. 43 passes through the installation hole 621, first the pumping pipe 43 is passed through the filter plate 2 and the submersible pump 44 is installed, and then the submersible pump 44 is placed together with the filter plate 2 at the bottom of the well pipe 42; the filtering treatment of the filtering mechanism 6 reduces the influence of mud and sand impurities on the pumping efficiency of the submersible pump 44; the same group of positive pressure will be connected with the end of the pumping pipe 43 of the mechanism away from the submersible pump 44, using the manifold 45, and connected to the pumping device 2 46 at the end of the manifold 45 away from the pumping pipe 43, so that the water of a group of positive pressure precipitation mechanisms 4 can be discharged at the same time by using the pumping device 2 46.

[0041] A negative pressure dewatering mechanism 5 is arranged between every two groups of positive pressure dewatering mechanisms 4. The negative pressure dewatering mechanism 5 comprises a drainage plate 51 and a drainage pipe 52. One end of the drainage plate 51 is inserted into the foundation pit 1 to be constructed, and the other end is extended above the foundation pit 1 to be constructed. The drainage plate 51 above the foundation pit 1 to be constructed is covered with a sand layer 53. The water discharged from the foundation pit 1 to be constructed by the drainage plate 51 will be absorbed by the sand layer 53. A guide plate 511 is installed at one end of the drainage plate 51 inserted into the foundation pit 1 to be constructed. The guide plate 511 is used to The drainage board 51 is fully unfolded to increase the drainage efficiency; at the same time, a sand layer 53 is used to cover the drainage pipe 52, and a pumping device 54 is installed at the end of the drainage pipe 52 away from the sand layer 53, and the water in the sand layer 53 is pumped out through the drainage pipe 52 by the pumping device 54; the surface of the foundation pit 1 to be constructed is covered with a waterproof membrane 55 to form a relatively closed space in the foundation pit 1 to be constructed, and then precipitation work is carried out to generate a pressure difference inside and outside the foundation pit 1 to be constructed, thereby improving the drainage efficiency of the drainage board 51.

[0042] Embodiment 2: A construction method of a positive and negative pressure combined dewatering mechanism for a narrow and long foundation pit in a reclamation stratum: S100, a water-stop curtain 3 is inserted around the foundation pit (1) to be constructed, and the water-stop curtain 3 is inserted through the foundation pit to be processed into the deep soil 2; S200, a plurality of positive pressure dewatering mechanisms 4 are arranged in the foundation pit 1 to be constructed, and a plurality of positive pressure dewatering mechanisms 4 in the same row are grouped together; one end of a water pumping pipe 43 is installed together with a submersible pump 44, and then the end of the water pumping pipe 43 installed with the submersible pump 44 is placed into the positive pressure dewatering mechanism 4; then, a manifold 45 is used to connect the water pumping pipes 43 in the same group, and the manifold 45 is connected to a second water pumping device 46; S210, the positive pressure dewatering mechanism 4 includes a dewatering blind well 41 and a well pipe 42 inserted in the dewatering blind well 41. First, the main body of the dewatering blind well 41 that passes through the foundation pit 1 to be constructed to the deep soil 2 is excavated, and then a filtering device is installed in the well pipe 42, and the well pipe 42 is placed in the dewatering blind well 41. Subsequently, one end of the pumping pipe 43 equipped with a submersible pump 44 is placed in the well pipe 42. At the same time, when the other end of the pumping pipe 43 extends out of the dewatering blind well 41, the dewatering blind well 41 is blocked with a soil layer, and at this time, the pumping pipes 43 of the same group are connected to the confluence pipe 45; S211, the filter mechanism 6 includes a filter plate 1 61 and a filter plate 2 62, the filter plate 1 61 is arranged in the water inlet hole 421 of the side wall of the well pipe 42; before installing the filter plate 2 62, firstly, the water pump 43 which has not yet been installed with the submersible pump 44 is passed through the installation hole 621 on the filter plate 2 62, then the submersible pump 44 is installed, and then the submersible pump 44 and the filter plate 2 62 are put into the well pipe 42; S300, a plurality of negative pressure dewatering mechanisms 5 are arranged in the foundation pit 1 to be constructed, and the negative pressure dewatering mechanisms 5 are located between every two positive pressure dewatering mechanisms 4, that is, the positive pressure dewatering mechanisms 4 and the negative pressure dewatering mechanisms 5 are arranged alternately, and the negative pressure dewatering mechanisms 5 are connected to a pumping device 54; at the same time, a waterproof membrane 55 is laid on the foundation pit 1 to be constructed, and the waterproof membrane 55 is fixed with fixing bolts 56; S310, the negative pressure dewatering mechanism 5 includes a drainage board 51 and a drainage pipe 52. A guide plate 511 is installed at one end of the drainage board 51 that needs to be inserted into the foundation pit 1 to be constructed. Then, a plate inserting machine is used to insert the drainage board 51 into the foundation pit 1 to be constructed through the guide plate 511, and the other end of the drainage board 51 is left outside the foundation pit 1 to be constructed. Then, a group of drainage boards 51 left outside the foundation pit 1 to be constructed are covered with a sand layer 53, and at the same time, the drainage pipe 52 is also buried in the sand layer 53, and the drainage pipe 52 is then connected to a pumping device 54; S311, a guide chamfer 5111 is provided at one end of the guide plate 511 close to the deep soil 2; S400, start the pumping device 1 54 and the pumping device 2 46, and discharge the water discharged from the foundation pit 1 to be constructed to the outside of the foundation pit 1 to be constructed through the pumping device 1 54 and the pumping device 2 46.

[0043] The implementation principle of the embodiment of the present application is: A combined positive and negative pressure dewatering method is used in the foundation pit 1 to be constructed, that is, the positive pressure dewatering mechanism 4 and the negative pressure dewatering mechanism 5 are alternately arranged, and the negative pressure dewatering mechanism 5 is arranged between the positive pressure dewatering mechanisms 4, so as to make full use of the effective space to improve the dewatering efficiency; at the same time, the negative pressure dewatering mechanism 5 can also improve the dewatering efficiency of the positive pressure dewatering mechanism 4 by creating a pressure difference; through the above method, the efficiency of foundation pit dewatering is effectively improved to cope with the dewatering work with tight construction period.

[0044] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum, comprising a foundation pit to be constructed (1) and a deep soil layer (2) below the foundation pit to be constructed (1), characterized in that: The foundation pit (1) to be constructed is provided with a water-stop curtain (3) in the circumferential direction, and the water-stop curtain (3) penetrates the foundation pit (1) to be constructed in the up-down direction and is inserted into the deep soil (2); a plurality of groups of positive-pressure dewatering mechanisms (4) are provided in the foundation pit (1) to be constructed, and a plurality of groups of negative-pressure dewatering mechanisms (5) are provided between the plurality of groups of positive-pressure dewatering mechanisms (4), and each group of the positive-pressure dewatering mechanisms (4) and the negative-pressure dewatering mechanisms (5) are alternately provided.

2. The positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum according to claim 1 is characterized by: Each group of the negative pressure dewatering mechanisms (5) is provided with a plurality of drainage plates (51) and a drainage pipe (52); one end of the drainage plate (51) is inserted into the foundation pit (1) to be constructed along the up-down direction, and the other end of the drainage plate (51) is located outside the foundation pit (1) to be constructed, and the portion of the drainage plate (51) located outside the foundation pit (1) to be constructed is covered with a sand layer (53); one end of the drainage pipe (52) is arranged in the sand layer (53), and the other end is provided with a pumping device (54); a water-proof membrane (55) is provided on the upper surface of the foundation pit (1) to be constructed, and a plurality of fixing bolts (56) are provided between the water-proof membrane (55) and the surface of the foundation pit (1) to be constructed.

3. The positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum according to claim 2 is characterized by: A guide plate (511) is provided at one end of the drainage plate (51) inserted into the foundation pit (1) to be constructed.

4. The positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum according to claim 3 is characterized by: A guide chamfer (5111) is provided at one end of the guide plate (511) close to the deep soil (2).

5. The positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum according to claim 1 is characterized by: The positive pressure dewatering mechanism (4) comprises a dewatering blind well (41) and a well pipe (42) inserted into the dewatering blind well (41); the dewatering blind well (41) passes through the foundation pit (1) to be constructed to the deep soil (2); a plurality of water inlet holes (421) are arranged on the side wall of the well pipe (42); a water pumping pipe (43) is arranged in the well pipe (42); a submersible pump (44) is arranged at one end of the water pumping pipe (43) inserted into the well pipe (42); the other end of the water pumping pipe (43) is located outside the foundation pit (1) to be constructed; and a filtering mechanism (6) is arranged in the well pipe (42).

6. The positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum according to claim 2 is characterized by: A plurality of the positive pressure dewatering mechanisms (4) in the same row form a group. A conduit (45) is provided at one end of the water pumping pipe (43) in a group of the positive pressure dewatering mechanisms (4) away from the submersible pump (44). The conduits (45) in a group are interconnected. A second water pumping device (46) is provided at one end of the conduit (45) away from the water pumping pipe (43).

7. The positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum according to claim 2 is characterized by: The filtering mechanism (6) comprises a first filter plate (61) and a second filter plate (62); the first filter plate (61) is arranged in the water inlet hole (421); the second filter plate (62) is arranged in the well pipe (42) close to the side of the submersible pump (44); and the second filter plate (62) is provided with a mounting hole (621) for the water pump (43) to pass through.

8. A construction method of a positive and negative pressure combined dewatering mechanism for a narrow and long foundation pit in a reclamation stratum, characterized in that: S100, a water-stop curtain (3) is inserted in the circumferential direction around the foundation pit (1) to be constructed, and the water-stop curtain (3) is inserted through the foundation pit to be processed into the deep soil (2); S200, a plurality of positive pressure dewatering mechanisms (4) are arranged in the foundation pit (1) to be constructed, and the plurality of positive pressure dewatering mechanisms (4) in the same row form a group; one end of a water pumping pipe (43) is installed together with a submersible pump (44), and then the end of the water pumping pipe (43) installed with the submersible pump (44) is placed in the positive pressure dewatering mechanism (4); then, a manifold (45) is used to connect the water pumping pipes (43) in the same group, and the manifold (45) is connected to a second water pumping device (46); S300, a plurality of groups of negative pressure dewatering mechanisms (5) are arranged in the foundation pit (1) to be constructed, wherein the negative pressure dewatering mechanism (5) is located between every two groups of positive pressure dewatering mechanisms (4), that is, the positive pressure dewatering mechanism (4) and the negative pressure dewatering mechanism (5) are arranged alternately, and the negative pressure dewatering mechanism (5) is connected to a pumping device (54); at the same time, a water-blocking membrane (55) is laid on the foundation pit (1) to be constructed, and the water-blocking membrane (55) is fixed with fixing bolts (56); S400, start the pumping device 1 (54) and the pumping device 2 (46), and discharge the water discharged from the foundation pit (1) to the outside of the foundation pit (1) through the pumping device 1 (54) and the pumping device 2 (46).

9. The positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum according to claim 8 is characterized by: S210, the positive pressure dewatering mechanism (4) comprises a dewatering blind well (41) and a well pipe (42) inserted in the dewatering blind well (41), firstly, the main body of the dewatering blind well (41) penetrating the foundation pit (1) to be constructed to the deep soil (2) is excavated, then a filtering device is installed in the well pipe (42), and the well pipe (42) is placed in the dewatering blind well (41), and then one end of the pumping pipe (43) equipped with a submersible pump (44) is placed in the well pipe (42), and at the same time, the dewatering blind well (41) is blocked with a soil layer when the other end of the pumping pipe (43) extends out of the dewatering blind well (41), and at this time, the pumping pipe (43) of the same group is connected to the confluence pipe (45); S211, the filtering mechanism (6) comprises a filter plate 1 (61) and a filter plate 2 (62), wherein the filter plate 1 (61) is arranged in the water inlet hole (421) of the side wall of the well pipe (42); before installing the filter plate 2 (62), firstly, a water suction pipe (43) on which a submersible pump (44) is not installed is passed through the installation hole (621) on the filter plate 2 (62), and then the submersible pump (44) is installed, and then the submersible pump (44) and the filter plate 2 (62) are placed into the well pipe (42).

10. The positive and negative pressure combined dewatering structure for a narrow and long foundation pit in a reclamation stratum according to claim 8, characterized in that: S310, the negative pressure dewatering mechanism (5) comprises a drainage board (51) and a drainage pipe (52), and a guide plate (511) is installed at one end of the drainage board (51) to be inserted into the foundation pit (1) to be constructed, and then a plate inserting machine is used to insert the drainage board (51) into the foundation pit (1) to be constructed through the guide plate (511), and the other end of the drainage board (51) is left outside the foundation pit (1) to be constructed, and then the set of drainage boards (51) left outside the foundation pit (1) to be constructed is covered with a sand layer (53), and at the same time, the drainage pipe (52) is also buried in the sand layer (53), and the drainage pipe (52) is then connected to a pumping device (54); S311, a guide chamfer (5111) is provided at one end of the guide plate (511) close to the deep soil (2).

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