Integrated Precipitation-Support Retaining Structure System and Design Method

Abstract

This invention belongs to the field of building construction technology, and particularly relates to a dewatering-support integrated retaining structure system and its design method. The retaining structure system includes: several support units, circumferentially arranged at the edge of the proposed excavation pit; several dewatering units, circumferentially arranged at the edge of the proposed excavation pit, with the dewatering units spaced apart within the retaining structure system and connected to adjacent support units; a filter assembly, located outside the dewatering units; a sealing assembly, located at the bottom inside the dewatering units; and a drainage assembly, located inside the dewatering units, used to drain accumulated water inside the dewatering units. This invention solves the problems of complex construction procedures, long construction period, low dewatering efficiency, weak bearing capacity, large footprint, and high cost in existing technologies. Furthermore, since both the support units and dewatering units are located at the edge of the pit, the space requirements within the pit are reduced, the land area is decreased, and the layout is not restricted by the construction site, while ensuring efficient dewatering within the pit.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, and in particular relates to a combined dewatering-support structure system and design method. Background Technology

[0002] The rapid development of modern urban construction has driven the intensive implementation of projects such as underground space development, integrated utility tunnels, and large-scale commercial complexes. As a core component ensuring the safe construction of underground structures, the safety and stability of foundation pit engineering directly affect the overall reliability and long-term durability of the project. Currently, commonly used foundation pit support methods mainly include pile support, diaphragm walls, soil nailing walls, and sheet pile support. For example, pile support uses multiple rows of piles to distribute earth pressure; diaphragm walls form a closed support system with continuous rigid walls; soil nailing walls enhance overall stability through the synergistic effect of soil nails and soil; and sheet piles are widely used in long, narrow foundation pits due to their high turnover rate and flexibility.

[0003] In traditional foundation pit engineering, especially in areas with high groundwater levels, dewatering system design is required simultaneously with the design of the support structure. The separate installation of the dewatering system and the support structure can easily lead to complex construction procedures, extended construction periods, and increased costs. Furthermore, in the design of some narrow municipal foundation pits, due to space constraints for excavation and structural construction within the pit, dewatering wells are generally placed outside the pit, occupying space around the pit and restricting the layout of the construction site. This also significantly reduces the efficiency of dewatering within the pit. In addition, the functional separation of the support structure and the dewatering system makes it difficult to dynamically adjust according to changes in soil permeability or groundwater level fluctuations during excavation. This can easily lead to uneven stress on the support structure and insufficient dewatering efficiency, ultimately affecting the overall safety and economy of the foundation pit project. While existing technologies attempt to combine support and dewatering functions, they mostly employ simple superposition methods. Currently, the design theory for single-type retaining pile structures is relatively complete in existing standards and specifications. However, when different types of retaining piles are used in combination, there is a lack of systematic collaborative design theory. This makes it difficult to scientifically guarantee the overall support and dewatering effects of composite retaining structures, thus hindering the promotion and application of engineering projects.

[0004] Therefore, it is necessary to design a combined dewatering-support structure system and design method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a combined dewatering and support structure system and design method that integrates support and dewatering functions, thereby improving construction efficiency and enhancing adaptability.

[0006] To achieve the above objectives, the present invention provides the following solution: a combined rainwater-support structure system, comprising:

[0007] Several support units are arranged circumferentially at the edge of the excavation pit to be excavated;

[0008] Several dewatering units are arranged circumferentially at the edge of the excavation pit to be excavated. The dewatering units are arranged at intervals within the retaining structure system and connected to adjacent support units. The dewatering units are connected to the support units by locking buckles.

[0009] A filter assembly is disposed outside the precipitation unit;

[0010] A sealing assembly is disposed at the bottom of the interior of the precipitation unit, and the sealing assembly is used to seal the bottom of the precipitation unit;

[0011] A drainage assembly is disposed inside the precipitation unit, and the drainage assembly is used to drain the accumulated water inside the precipitation unit.

[0012] According to the present invention, a combined dewatering-support structure system is provided, wherein the dewatering unit has openings on the side wall facing the pit, the openings are arranged along the depth direction of the pit, the part of the dewatering unit away from the pit and above the bottom of the pit is a closed structure, and the part of the dewatering unit away from the pit and below the bottom of the pit has openings, the openings being arranged in one or more of the following patterns: quincunx, equidistant rectangles.

[0013] According to the present invention, a combined rainwater-support structure system is provided, wherein the filter component includes a filter screen, the filter screen covers the outside of the rainwater unit, and sand filter material is filled between the filter screen and the hole wall of the installation hole of the rainwater unit.

[0014] According to the present invention, a combined rainwater-support structure system is provided, wherein the sealing component includes a bottom seal, which is disposed at the bottom of the rainwater unit, and a support is fixedly connected to the top of the bottom seal. The support is vertically arranged, and a permeable support plate is fixedly connected to the top of the support plate. The drainage component is disposed at the top of the permeable support plate.

[0015] According to the present invention, a combined rainwater-support structure system is provided, wherein the drainage component includes a water pump, the water pump is disposed at the top of the permeable support plate, the outlet end of the water pump is fixedly connected to one end of a water outlet pipe, and the other end of the water outlet pipe extends out of the top of the rainwater unit.

[0016] A design method for a combined precipitation-support retaining structure system includes the following steps:

[0017] Calculate the water inflow volume of the foundation pit based on geological conditions. Calculate the precipitation unit flow rate based on aquifer permeability and precipitation unit structure. Based on the water inflow of the foundation pit and precipitation unit flow Calculate the number of precipitation units Based on the number of precipitation units Calculate the number of support units Based on the calculated water inflow volume of the foundation pit Precipitation unit flow Number of precipitation units Number of support units The data is used to calculate the precipitation performance of the precipitation unit;

[0018] Based on the selection parameters of the precipitation unit and the support unit, the data of the full-length equivalent bending stiffness, full-length equivalent bending bearing capacity, and full-length equivalent section shear bearing capacity of the composite integrated retaining structure system are calculated. Based on the calculated data of the full-length equivalent bending stiffness, full-length equivalent bending bearing capacity, and full-length equivalent section shear bearing capacity, the retaining performance of the composite integrated retaining structure system is obtained.

[0019] Stability calculations were performed based on the structural form of the composite integrated enclosure structure system. Once the stability requirements were met, the dewatering unit and support unit were installed to form the composite integrated enclosure structure system.

[0020] The present invention provides a design method for a combined dewatering and support retaining structure system, wherein the water inflow of the foundation pit is calculated based on geological conditions. ,include:

[0021] Water inflow of the complete submersible well foundation pit Calculation formula:

[0022] ;

[0023] in, This represents the total water consumption for dewatering the foundation pit. Permeability coefficient; This refers to the thickness of the unconfined aquifer. Draw down the water level in the foundation pit; Radius of precipitation influence; The radius of the equivalent circle enclosed by the group of precipitation wells;

[0024] Inflow of water from incomplete well foundation pit Calculation formula:

[0025] ;

[0026] ;

[0027] in, The thickness from the dynamic water level of the foundation pit to the surface of the aquifer; The length of the effective working portion of the precipitation unit;

[0028] Confined water complete well foundation pit water inflow Calculation formula:

[0029] ;

[0030] in, The thickness of the confined aquifer;

[0031] Confined water inflow rate of incomplete well foundation pit Calculation formula:

[0032] ;

[0033] Water inflow of pressurized-unconfined incomplete well foundation pit Calculation formula:

[0034] ;

[0035] Precipitation unit flow Calculation formula:

[0036] ;

[0037] in, Where is the radius of the precipitation unit; when the precipitation unit is square, , The area of ​​the precipitation unit;

[0038] Number of precipitation units Calculation formula:

[0039] ;

[0040] in, Take the integer part;

[0041] Number of support units Calculation formula:

[0042] ;

[0043] in, L is the length of the support unit; M is the total length of the support, and m is an integer.

[0044] Based on the design method of the integrated rainwater-support structure system of the present invention, the formula for calculating the equivalent bending stiffness of the entire length of the retaining structure system is as follows:

[0045] ;

[0046] ;

[0047] ;

[0048] in, The equivalent bending stiffness of the entire length of the enclosure structure system; For the bending stiffness of the support unit; For the bending stiffness of the precipitation unit; The elastic modulus of the support unit; The elastic modulus of precipitation unit; The moment of inertia of the support unit; The moment of inertia of the precipitation unit;

[0049] Formula for calculating the equivalent flexural capacity of the entire length of the enclosure structure system:

[0050] ;

[0051] ;

[0052] ;

[0053] in, The equivalent bending capacity of the entire length of the enclosure structure system; The bending bearing capacity of the support unit; The bearing capacity of the support structure for the precipitation unit; For the vertical displacement of the support unit; This represents the vertical displacement of the precipitation unit; This refers to the axial coordinate position of the support unit; This represents the axial coordinate position of the precipitation unit;

[0054] Formula for calculating the shear capacity of the equivalent section along the entire length of the enclosure structure:

[0055] ;

[0056] ;

[0057] ;

[0058] ;

[0059] in, The shear bearing capacity of the equivalent section along the entire length of the enclosure structure system; For the shear force of the support unit; For the shear force of the precipitation unit; The web height in the support unit and the dewatering unit; The thickness of the web in the support unit and the dewatering unit; This is the design value for the shear strength of the steel.

[0060] Compared with the prior art, the present invention has the following advantages and technical effects:

[0061] 1. This invention combines the precipitation unit with the support unit, which effectively improves the overall bending stiffness and bending bearing capacity of the retaining structure system and reduces the deformation of the structure during the support process.

[0062] 2. By combining the dewatering unit with the support unit, this invention solves the problem of excessive space occupation of dewatering wells set inside or outside the foundation pit in the prior art, so that the setting of dewatering wells is not restricted by the construction site layout, and is fully applicable to narrow foundation pit projects in cities.

[0063] 3. By combining the precipitation unit with the support unit, the present invention can achieve simultaneous precipitation and support, effectively simplifying the construction process, reducing the construction period, and saving construction costs.

[0064] 4. By combining the dewatering unit with the support unit, the present invention can dynamically adjust according to the changes in stratum permeability or groundwater level fluctuations during excavation, thus solving the problems of uneven stress on the retaining structure and insufficient dewatering efficiency in the prior art.

[0065] 5. This invention proposes a novel quantitative design method for composite structures, which enriches the content of composite pile design methods and makes up for the deficiencies in the current specifications. Attached Figure Description

[0066] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0067] Figure 1 This is a schematic diagram of the integrated rainwater protection and retaining structure system of the present invention;

[0068] Figure 2 This is a schematic diagram of the precipitation unit of the present invention;

[0069] Figure 3 This is a schematic diagram of the precipitation surface of the precipitation unit in this invention;

[0070] Figure 4 This is a schematic diagram of the soil-facing surface of the precipitation unit of the present invention;

[0071] Figure 5 This is a schematic diagram of the first connection between the precipitation unit and the support unit according to an embodiment of the present invention;

[0072] Figure 6 This is a schematic diagram of a second connection between the precipitation unit and the support unit according to an embodiment of the present invention;

[0073] Figure 7 This is a flowchart illustrating the design of the present invention.

[0074] The components include: 1. Filter holes; 2. Filter screen; 3. Locking buckle; 4. Bottom sealing; 5. Support; 6. Permeable support plate; 7. Water pump; 8. Opening; 9. Sand filter media; and 10. Water outlet pipe. Detailed Implementation

[0075] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0076] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0077] Reference Figures 1 to 7 As shown, the present invention provides a precipitation-support integrated retaining structure system, comprising:

[0078] Several support units are arranged circumferentially at the edge of the excavation pit to be excavated;

[0079] The support unit is a retaining pile structure, which can be selected from one or more of steel sheet piles, steel pipe piles, steel section piles, and steel pipe concrete piles; the support unit is installed by direct insertion into the stratum or by drilling.

[0080] Several dewatering units are arranged circumferentially at the edge of the excavation pit to be excavated. The dewatering units are arranged at intervals within the retaining structure system and connected to adjacent support units. The dewatering units are connected to the support units through locking buckles 3.

[0081] The precipitation unit is a hollow structure, and one or more of the following can be selected: round steel pipe, square steel pipe, and special-shaped steel pipe.

[0082] The filter assembly is located outside the rainwater collection unit;

[0083] A sealing assembly is installed at the bottom inside the precipitation unit, and the sealing assembly is used to seal the bottom of the precipitation unit;

[0084] The drainage assembly is installed inside the rainwater unit and is used to drain the accumulated water inside the rainwater unit.

[0085] Furthermore, the dewatering unit has openings 8 on the side wall facing the pit, and the openings 8 are arranged along the depth direction of the pit. The part of the dewatering unit away from the pit and above the bottom of the pit is a closed structure, and the part of the dewatering unit away from the pit and below the bottom of the pit has openings 8. The arrangement of the openings 8 is one or more of the following: quincunx shape, equidistant rectangles.

[0086] The opening 8 is used to allow groundwater to seep into the interior of the dewatering unit before excavation of the foundation pit, so as to achieve groundwater dewatering within the area of ​​the foundation pit to be excavated; the closed structure of the dewatering unit can prevent groundwater outside the retaining structure from seeping into the interior of the dewatering unit.

[0087] Furthermore, the filtration assembly includes a filter screen 2, which covers the outside of the rainwater unit, and sand filter media 9 is filled between the filter screen 2 and the wall of the mounting hole of the rainwater unit.

[0088] The material of filter 2 is metal or plastic.

[0089] Furthermore, the sealing assembly includes a bottom seal 4, which is located at the bottom of the interior of the rainwater unit. A bracket 5 is fixedly connected to the top of the bottom seal 4. The bracket 5 is vertically arranged, and a permeable support plate 6 is fixedly connected to the top of the bracket 5. The drainage assembly is located at the top of the permeable support plate 6.

[0090] The bottom seal 4 prevents external soil particles from entering the precipitation unit along the bottom. The area between the permeable support plate 6 and the bottom seal 4 of the precipitation unit is a sedimentation section, used to deposit and store soil particles that seep into the precipitation unit during the precipitation process.

[0091] Furthermore, the drainage assembly includes a water pump 7, which is installed at the top of the permeable support plate 6. The outlet end of the water pump 7 is fixedly connected to one end of the water outlet pipe 10, and the other end of the water outlet pipe 10 extends out of the top of the rainwater unit.

[0092] After the dewatering unit is installed, pump 7 is used to pump water from inside the unit. Once the water level reaches the design dewatering level for the excavation of the foundation pit, the dewatering requirement is met.

[0093] A design method for a combined precipitation-support retaining structure system includes the following steps:

[0094] Calculate the water inflow volume of the foundation pit based on geological conditions. Calculate the precipitation unit flow rate based on aquifer permeability and precipitation unit structure. Based on the water inflow of the foundation pit and precipitation unit flow Calculate the number of precipitation units Based on the number of precipitation units Calculate the number of support units Based on the calculated water inflow volume of the foundation pit Precipitation unit flow Number of precipitation units Number of support units The data is used to calculate the precipitation performance of the precipitation unit;

[0095] Based on the selection parameters of the precipitation unit and the support unit, the data of the full-length equivalent bending stiffness, full-length equivalent bending bearing capacity, and full-length equivalent section shear bearing capacity of the composite integrated retaining structure system are calculated. Based on the calculated data of the full-length equivalent bending stiffness, full-length equivalent bending bearing capacity, and full-length equivalent section shear bearing capacity, the retaining performance of the composite integrated retaining structure system is obtained.

[0096] Stability calculations were performed based on the structural form of the composite integrated enclosure structure system. Once the stability requirements were met, the dewatering unit and support unit were installed to form the composite integrated enclosure structure system.

[0097] Furthermore, the water inflow volume of the foundation pit is calculated based on the geological conditions. ,include:

[0098] Water inflow of the complete submersible well foundation pit Calculation formula:

[0099] ;

[0100] in, This represents the total water consumption for dewatering the foundation pit. The permeability coefficient is m / d; The thickness of the unconfined aquifer is m; The depth of the foundation pit water level is measured in meters. The radius of influence of precipitation is m; The radius (m) of the equivalent circle enclosed by the group of precipitation wells;

[0101] Inflow of water from incomplete well foundation pit Calculation formula:

[0102] ;

[0103] ;

[0104] in, The thickness (m) from the dynamic water level of the foundation pit to the surface of the aquifer; The length (m) of the effective working portion of the precipitation unit;

[0105] Confined water complete well foundation pit water inflow Calculation formula:

[0106] ;

[0107] in, The thickness of the confined aquifer is in meters (m).

[0108] Confined water inflow rate of incomplete well foundation pit Calculation formula:

[0109] ;

[0110] Water inflow of pressurized-unconfined incomplete well foundation pit Calculation formula:

[0111] ;

[0112] Precipitation unit flow Calculation formula:

[0113] ;

[0114] in, Where is the radius of the precipitation unit; when the precipitation unit is square, , The area of ​​the precipitation unit;

[0115] Number of precipitation units Calculation formula:

[0116] ;

[0117] in, Take the integer part;

[0118] Number of support units Calculation formula:

[0119] ;

[0120] in, L is the length of the support unit (m); L is the total length of the support (m), where m is an integer.

[0121] Before calculating the number of support units, the depth and well spacing must be verified.

[0122] The integrated rainwater-support structure system consists of n rainwater units and m support units along the entire support length.

[0123] Furthermore, the formula for calculating the equivalent bending stiffness of the entire length of the enclosure structure system is as follows:

[0124] ;

[0125] ;

[0126] ;

[0127] in, The equivalent bending stiffness of the entire length of the enclosure structure system; For the bending stiffness of the support unit; For the bending stiffness of the precipitation unit; The elastic modulus of the support unit; The elastic modulus of precipitation unit; The moment of inertia of the support unit; The moment of inertia of the precipitation unit;

[0128] Formula for calculating the equivalent flexural capacity of the entire length of the enclosure structure system:

[0129] ;

[0130] ;

[0131] ;

[0132] in, The equivalent bending capacity of the entire length of the enclosure structure system; The bending bearing capacity of the support unit; The bearing capacity of the support structure for the precipitation unit; For the vertical displacement of the support unit; This represents the vertical displacement of the precipitation unit; This refers to the axial coordinate position of the support unit; d represents the axial coordinate position of the precipitation unit; d represents a mathematical operation symbol.

[0133] Formula for calculating the shear capacity of the equivalent section along the entire length of the enclosure structure:

[0134] ;

[0135] ;

[0136] ;

[0137] ;

[0138] in, The shear bearing capacity of the equivalent section along the entire length of the enclosure structure system; For the shear force of the support unit; For the shear force of the precipitation unit; The web height in the support unit and the dewatering unit; The thickness of the web in the support unit and the dewatering unit; This is the design value for the shear strength of the steel. This indicates that the shear force of the support unit and the shear force of the dewatering unit must simultaneously satisfy the requirement of this inequality.

[0139] When the retaining structure system adopts a support-type retaining structure, it should meet the requirements for embedded stability and pit bottom heave stability.

[0140] Requirements for the embedment stability of the supported retaining structure:

[0141] ;

[0142] Among them, K em E is the safety factor for embedded stability. ak E represents the standard value of the resultant active earth pressure on the outside of the foundation pit (kN); pk The standard value of the resultant passive earth pressure within the foundation pit (kN); z a1 z is the distance (m) from the point of application of the resultant force of the active earth pressure outside the foundation pit to the bottom of the retaining member; p1 The distance (m) is the distance from the point of application of the resultant passive earth pressure inside the foundation pit to the bottom of the retaining member.

[0143] Stability requirements for pit bottom heave of supported retaining structures:

[0144] ;

[0145] ;

[0146] ;

[0147] Among them, K he For the anti-uplift safety factor; γ m1 The unit weight of the soil above the bottom surface of the retaining structure outside the foundation pit (kN / m³) 3 );γ m2 The unit weight (kN / m³) of the soil above the bottom surface of the retaining structure in the foundation pit. 3 D is the soil layer thickness from the bottom of the foundation pit to the bottom of the retaining structure (m); h is the depth of the foundation pit (m); q0 is the uniformly distributed load on the ground (kPa); N c N q φ is the bearing capacity coefficient; c and φ are the cohesion (kPa) and internal friction angle (°) of the soil below the bottom surface of the retaining member.

[0148] When the enclosure structure system adopts a cantilever support structure, it should meet the requirements of embedded stability and overall stability.

[0149] Requirements for the embedment stability of cantilever support structures:

[0150] ;

[0151] Among them, z a2 z is the distance (m) from the point of application of the resultant force of the active earth pressure outside the foundation pit to the bottom of the retaining member; p2The distance (m) is the distance from the point of application of the resultant passive earth pressure inside the foundation pit to the bottom of the retaining member.

[0152] Overall stability requirements for cantilever support structures:

[0153] ;

[0154] ;

[0155] Among them, K s K is the overall stability safety factor for circular arc sliding. s,i Let c be the ratio of the anti-slip torque to the sliding torque of the i-th sliding arc; j、 φ j Let b be the cohesion (kPa) and internal friction angle (°) of the soil at the slip surface of the j-th soil strip; j Let θ be the width (m) of the j-th soil strip; j Let l be the angle (°) between the normal at the midpoint of the j-th soil strip's sliding arc surface and the vertical plane; j Let q be the length (m) of the slip arc segment of the j-th soil strip; j ΔG represents the standard value (kPa) of the additional distributed load acting on the j-th soil strip; j Let u be the self-weight of the j-th soil strip (kN); j Let be the pore water pressure (kPa) of the j-th soil strip on the slip surface.

[0156] Example:

[0157] In this embodiment, a combined dewatering and support retaining structure system is provided. The dewatering unit uses φ325 steel pipe piles with a pile thickness of 20mm. Filter holes 1, each 10mm in diameter, are drilled on the dewatering surface of the steel pipe piles, with a spacing of 20mm between holes arranged in a staggered pattern. The steel pipe piles have the same length as the sheet piles, and double-sided openings are made in the section below one-third of the pile length. The support unit uses Larssen IV sheet piles.

[0158] A 60-mesh (250 micrometers) filter screen 2 is arranged in the opening section of the steel pipe pile, and then a layer of steel wire mesh is wrapped around it to press the filter screen 2 down. Steel strips are welded to the edges of the steel wire mesh to fix the filter screen 2 in place. The filter screen 2 is made of stainless steel, and the steel wire mesh is made of 10-mesh stainless steel. The water pump 7 is installed on the permeable support plate 6, and the permeable support plate 6 is installed on the bottom sealing plate 4.

[0159] The first construction plan is as follows: (1) Clean the steel sheet pile and steel pipe pile lock, and then tightly interlock the steel sheet pile lock and steel pipe pile lock on the ground. Then weld the steel pipe pile and steel sheet pile 1 at the lock 3 position; (2) On-site personnel select the position of the steel pipe pile and mark it, and then use a drilling machine to drill a hole with a diameter of 650mm. Then clean the hole by changing the slurry; (3) Drive in the steel sheet pile 1, and the steel pipe is passively sunk into the borehole by welding the lock 3. Then drive in the steel sheet pile 2 to ensure that the lock 3 is tightly connected. Before the steel pipe pile is driven in, fill the lock 3 with butter asphalt mixture. When the steel sheet pile is driven in, use a pile driver to suspend the steel pipe pile to prevent it from sinking, and use a level to observe and correct to ensure that the inclination meets the requirements; (4) Fill the space between the steel pipe pile and the borehole with medium and coarse sand filter material 9 as a filter layer; (5) Hang the water pump 7 in the steel pipe pile to pump water. Ensure that the water pump 7 is 0.5-1m away from the bottom of the well.

[0160] The second construction plan is as follows: (1) The locking buckle 3 on one side of the steel pipe pile is extended by welding. The length of the extended locking buckle is not less than 200mm and the thickness is not less than 15mm; (2) The steel sheet pile 1 is driven in, and then a hole is drilled on the right side of the steel sheet pile 1 with a diameter of 650mm. Then the hole is cleaned by changing the slurry and cleaning the hole; (3) The steel pipe pile is slowly pressed into the hole by the pile driver. And ensure that the long locking buckle of the steel pipe pile is tightly connected with the steel sheet pile 1; (4) Fill the gap between the steel pipe pile and the drill hole with medium and coarse sand filter material 9 as a filter layer; (5) Drive the steel sheet pile 2 into the side of the short locking buckle of the steel pipe pile. Ensure that the locking buckle is tightly connected. When the steel sheet pile is driven in, the steel pipe pile is suspended by the pile driver to prevent it from sinking. During the pile driving process, the level is used to observe and correct to ensure that the inclination meets the requirements; (6) The water pump is hoisted into the steel pipe pile to pump water. Ensure that the water pump is 0.5-1m away from the bottom of the well.

[0161] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0162] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope of the present invention.

Claims

1. A combined rainwater-support structure system, characterized in that, include: Several support units are arranged circumferentially at the edge of the excavation pit to be excavated; Several dewatering units are arranged circumferentially at the edge of the excavation pit to be excavated. The dewatering units are arranged at intervals within the retaining structure system and are connected to adjacent support units. A filter assembly is disposed outside the precipitation unit; A sealing assembly is disposed at the bottom of the interior of the precipitation unit, and the sealing assembly is used to seal the bottom of the precipitation unit; A drainage assembly is disposed inside the precipitation unit, and the drainage assembly is used to drain the accumulated water inside the precipitation unit; The design method for a combined precipitation-support retaining structure system includes the following steps: Calculate the water inflow volume of the foundation pit based on geological conditions. Calculate the precipitation unit flow rate based on aquifer permeability and precipitation unit structure. Based on the water inflow of the foundation pit and precipitation unit flow Calculate the number of precipitation units Based on the number of precipitation units Calculate the number of support units Based on the calculated water inflow volume of the foundation pit Precipitation unit flow Number of precipitation units Number of support units The data is used to calculate the precipitation performance of the precipitation unit; Based on the selection parameters of the precipitation unit and the support unit, the data of the full-length equivalent bending stiffness, full-length equivalent bending bearing capacity, and full-length equivalent section shear bearing capacity of the composite integrated retaining structure system are calculated. Based on the calculated data of the full-length equivalent bending stiffness, full-length equivalent bending bearing capacity, and full-length equivalent section shear bearing capacity, the retaining performance of the composite integrated retaining structure system is obtained. Stability calculations were performed based on the structural form of the composite integrated enclosure structure system. Once the stability requirements were met, the dewatering unit and support unit were installed to form the composite integrated enclosure structure system. Formula for calculating the equivalent bending stiffness of the entire length of the enclosure structure system: ； ； ； in, The equivalent bending stiffness of the entire length of the enclosure structure system; For the bending stiffness of the support unit; For the bending stiffness of the precipitation unit; The elastic modulus of the support unit; The elastic modulus of precipitation unit; The moment of inertia of the support unit; The moment of inertia of the precipitation unit; Formula for calculating the equivalent flexural capacity of the entire length of the enclosure structure system: ； ； ； in, The equivalent bending capacity of the entire length of the enclosure structure system; The bending bearing capacity of the support unit; The bearing capacity of the support structure for the precipitation unit; For the vertical displacement of the support unit; This represents the vertical displacement of the precipitation unit; This refers to the axial coordinate position of the support unit; d represents the axial coordinate position of the precipitation unit; d represents a mathematical operation symbol. Formula for calculating the shear capacity of the equivalent section along the entire length of the enclosure structure: ； ； ； ； in, The shear bearing capacity of the equivalent section along the entire length of the enclosure structure system; For the shear force of the support unit; For the shear force of the precipitation unit; The height of the web in the support unit and the dewatering unit; The thickness of the web in the support unit and the dewatering unit; This is the design value for the shear strength of the steel. This indicates that the shear force of the support unit and the shear force of the dewatering unit must simultaneously satisfy the requirement of this inequality.

2. The integrated rainwater-support structure system according to claim 1, characterized in that, The dewatering unit has an opening (8) on the side wall facing the pit. The opening (8) is arranged along the depth direction of the pit. The part of the dewatering unit away from the pit and above the bottom of the pit is a closed structure. The part of the dewatering unit away from the pit and below the bottom of the pit has an opening (8). The opening (8) is arranged in one or more of the following patterns: quincunx, equidistant rectangle.

3. The integrated rainwater-support composite retaining structure system according to claim 1, characterized in that, The filtration assembly includes a filter screen (2), which covers the outside of the rainwater unit, and sand filter material (9) is filled between the filter screen (2) and the hole wall of the rainwater unit mounting hole.

4. The integrated rainwater-support composite retaining structure system according to claim 1, characterized in that, The sealing assembly includes a bottom seal (4), which is located at the bottom of the interior of the rainwater unit. A bracket (5) is fixedly connected to the top of the bottom seal (4). The bracket (5) is vertically arranged, and a permeable support plate (6) is fixedly connected to the top of the bracket (5). The drainage assembly is located at the top of the permeable support plate (6).

5. The integrated rainwater-support composite retaining structure system according to claim 4, characterized in that, The drainage assembly includes a water pump (7), which is located at the top of the permeable support plate (6). The outlet end of the water pump (7) is fixedly connected to one end of a water outlet pipe (10), and the other end of the water outlet pipe (10) extends out of the top of the rainwater unit.

6. The integrated rainwater-support structure system according to claim 1, characterized in that, The calculation of the pit water inflow based on geological conditions ,include: Complete well foundation pit water inflow Calculation formula: ； in, This represents the total water consumption for dewatering the foundation pit. Permeability coefficient (m / d); The thickness of the unconfined aquifer (m); Drawdown of the foundation pit water level (m); Radius of precipitation influence (m); The radius (m) of the equivalent circle enclosed by the group of precipitation wells; Inflow of water from incomplete well foundation pit Calculation formula: ； ； in, The thickness (m) from the dynamic water level of the foundation pit to the ground surface of the aquifer. The length (m) of the effective working part of the precipitation unit; Confined water complete well foundation pit water inflow Calculation formula: ； in, Thickness of the confined aquifer (m); Confined water inflow rate of incomplete well foundation pit Calculation formula: ； Water inflow of pressurized-unconfined incomplete well foundation pit Calculation formula: ； Precipitation unit flow Calculation formula: ； in, Where is the radius of the precipitation unit; when the precipitation unit is square, , The area of ​​the precipitation unit; Number of precipitation units Calculation formula: ； in, Take the integer part; Number of support units Calculation formula: ； in, L is the length of the support unit (m); L is the total length of the support (m), where m is an integer.

Images