Deep foundation pit advance support system and construction method thereof

Abstract

The invention relates to the technical field of rock-soil deep foundation pit construction, and provides a deep foundation pit advance support system and a construction method thereof.The deep foundation pit advance support system comprises an enclosure structure, a foundation pit support structure and a support structure, the vertical supporting structures are supported on the inner walls of the enclosure structures on the two sides at intervals in the length direction of the enclosure structures; and the horizontal supporting structure is arranged at the bottom of the enclosure structure, is in sealing connection with the inner walls of the periphery of the enclosure structure, and seals the bottom of the enclosure structure and the bottom of the foundation pit at intervals. According to the scheme, the trenching machine is used for constructing the inner support, the assembled finished inner support is adopted, modular assembly can be achieved, and disassembly is convenient. The effective support is additionally arranged above the bottom of the foundation pit, the inner support system is completed before the foundation pit is excavated, and the inner support system belongs to an advanced support structure system, so that a stable support point exists at the bottom of the foundation pit before the foundation pit is excavated, and the risk of instability and overturning of the bottom of the foundation pit in the excavation process of the foundation pit is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of deep foundation pit construction in geotechnical engineering, and particularly relates to a deep foundation pit advanced support system and a construction method thereof. Background Art

[0002] With the acceleration of the urbanization process, the rapid development of urban construction, the continuous expansion of the urban scale, and the rapid growth of the urban population, many cities have suffered from various urban problems to varying degrees, such as tight construction land, crowded living space, traffic jams, backward infrastructure, ecological imbalance, and environmental deterioration. These problems have had a great impact on people's living conditions and also restricted the further development of urban economy and society, becoming an obstacle to the sustainable development of modern cities. Against this background, the development of urban underground space has shifted from the artificial engineering construction in the 1980s to the development strategy of underground space development and utilization with the goal of "urban sustainable development" in the 1990s;

[0003] In recent years, a large number of underground space development projects have emerged, such as urban subways, underground squares, underground roads, underground railways, underground parking lots, underground offices and residences, etc. During the construction of underground projects, there are often problems in deep foundation pit construction, facing a series of problems caused by geological and hydrogeological engineering such as underground rock and soil pressure and water pressure. Therefore, foundation pit support measures need to be taken;

[0004] Deep foundation pit support generally includes cast-in-place pile support, pile-anchor support, diaphragm wall support, pipe pile support, etc. Traditional support needs to consider the solution of problems such as anti-heave, anti-overturning, and groundwater water stop. Usually, a relatively long support length needs to be embedded below the bottom of the pit to meet the stability requirements during the foundation pit excavation stage. Otherwise, it is prone to instability. Summary of the Invention

[0005] The purpose of the present invention is to solve at least one technical problem in the background art, and provide a deep foundation pit advanced support system and a construction method thereof.

[0006] To achieve the above purpose, the present invention provides a deep foundation pit advanced support system, including:

[0007] A retaining structure, which is supported around the inside of the foundation pit to retain the foundation pit;

[0008] A plurality of vertical support structures, along the length direction of the retaining structure, each vertical support structure is supported on the inner walls of the two retaining structures at intervals;

[0009] A horizontal support structure, which is arranged at the bottom of the retaining structure and is hermetically connected to the inner walls around the retaining structure, and hermetically separates the bottom of the retaining structure from the bottom of the foundation pit.

[0010] According to one aspect of the present invention, the retaining structure is a retaining diaphragm wall or a retaining pile.

[0011] According to one aspect of the present invention, the vertical support structure includes: a capping beam, a first support, first support reinforcement bars, columns, column reinforcement bars, a second support, second support reinforcement bars, a third support, third support reinforcement bars, a bottom support, bottom support reinforcement bars, partition formworks, and pouring holes;

[0012] A plurality of partition formworks arranged at intervals are provided between the first support reinforcement bars, the second support reinforcement bars, the third support reinforcement bars, and the bottom support reinforcement bars, and pouring holes are reserved between the partition formworks. After pouring concrete through the pouring holes, connection and fixation are achieved;

[0013] The capping beam is supported on the tops of both sides of the retaining structure;

[0014] The first support, the second support, the third support, and the bottom support are made by pouring concrete through the first support reinforcement bars, the second support reinforcement bars, the third support reinforcement bars, and the bottom support reinforcement bars;

[0015] Both ends of the first support are respectively connected to the capping beams on both sides;

[0016] Both ends of the second support, the third support, and the bottom support are respectively supported on the inner walls on both sides of the retaining structure;

[0017] The column reinforcement bars are arranged in the middle of the first support reinforcement bars, the second support reinforcement bars, the third support reinforcement bars, and the bottom support reinforcement bars;

[0018] The column is made by pouring concrete through the column reinforcement bars.

[0019] According to one aspect of the present invention, anti - detachment reinforcement bars are provided at the upper corners of the joints between the second support and the third support and the inner wall of the retaining structure, and steel section brackets are provided at the lower corners.

[0020] According to one aspect of the present invention, the partition formworks are wooden formworks, foam formworks, steel formworks, plastic formworks, or aluminum alloy formworks.

[0021] According to one aspect of the present invention, the vertical support structure is formed by connecting multiple groups of vertical support units;

[0022] Each of the vertical support units includes: a horizontal steel support and a vertical connecting steel section;

[0023] The horizontal steel support is formed by a steel support and swivel joints arranged at both ends of the steel support;

[0024] A plurality of the horizontal steel supports are arranged at intervals in the vertical direction, and both ends of each of the horizontal steel supports are connected by the vertical connecting steel sections.

[0025] To achieve the above object, the present invention further provides a construction method for a deep foundation pit advanced support system, including underwater construction and dewatering construction, comprising:

[0026] Construct the retaining structure in sections;

[0027] Using a grooving machine, construct a groove structure for supporting the vertical support structure and the horizontal support structure in sections on the inner wall of the retaining structure;

[0028] Install each vertical support structure in sections;

[0029] When the construction is underwater construction, gradually excavate the foundation pit. After excavating to the bottom of the foundation pit, install a horizontal support structure at the bottom of the retaining structure for bottom sealing. After bottom sealing, pump out the water in the foundation pit;

[0030] When the construction is dewatering construction, lower the water level in the pit to a preset distance from the bottom of the foundation pit, then gradually excavate the foundation pit. After the excavation is completed, install a horizontal support structure at the bottom of the retaining structure for bottom sealing.

[0031] According to one aspect of the present invention, the vertical support structure includes: a capping beam, a first support, first support steel bars, columns, column steel bars, a second support, second support steel bars, a third support, third support steel bars, a bottom support, bottom support steel bars, partition templates, and pouring holes;

[0032] A plurality of partition templates arranged at intervals are provided between the first support steel bars, the second support steel bars, the third support steel bars, and the bottom support steel bars. Pouring holes are reserved between the partition templates, and connection and fixation are achieved by pouring concrete through the pouring holes;

[0033] The capping beam is supported on the tops of both sides of the retaining structure;

[0034] The first support, the second support, the third support, and the bottom support are made by pouring concrete through the first support steel bars, the second support steel bars, the third support steel bars, and the bottom support steel bars;

[0035] Both ends of the first support are respectively connected to the capping beams on both sides;

[0036] Both ends of the second support, the third support, and the bottom support are respectively supported on the inner walls on both sides of the retaining structure;

[0037] The column reinforcement bars are arranged in the middle of the first support reinforcement bars, the second support reinforcement bars, the third support reinforcement bars, and the bottom support reinforcement bars;

[0038] The column is made by pouring concrete with the column reinforcement bars;

[0039] The method of installing each vertical support structure in sections is as follows: install the first support reinforcement bars, the second support reinforcement bars, the third support reinforcement bars, the bottom support reinforcement bars, the column reinforcement bars, and the partition formworks in sections, and reserve pouring holes between the partition formworks;

[0040] Pour concrete through the pouring holes to construct the supports and columns inside the retaining structure in the foundation pit after completion.

[0041] According to one aspect of the present invention, the vertical support structure is formed by connecting multiple groups of vertical support units;

[0042] Each of the vertical support units includes: a horizontal steel support and a vertical connecting section steel;

[0043] The horizontal steel support is formed by a steel support and swivel joints arranged at both ends of the steel support;

[0044] Multiple horizontal steel supports are arranged at intervals along the vertical direction, and both ends of each horizontal steel support are connected by the vertical connecting section steel;

[0045] The method of installing each vertical support structure in sections is as follows: connect the horizontal steel support and the vertical connecting section steel to form a vertical support unit, and connect multiple groups of vertical support units side by side to form a prefabricated vertical support structure;

[0046] Install each vertical support structure in sections, and make each vertical support structure closely connected to the retaining structure by adjusting the swivel joints.

[0047] According to the solution of the present invention, the solution of the present invention uses a grooving machine to construct the internal support, avoiding the traditional method of constructing the internal support while excavating the foundation pit edge, with higher construction efficiency and greatly saving the construction period.

[0048] The solution of the present invention uses a grooving machine to construct the internal support, and adopts a prefabricated finished internal support, which can be assembled modularly and is convenient to demolish.

[0049] An effective support is added above the bottom of the foundation pit for a row of internal supports (vertical support structures). Before the excavation of the foundation pit, the internal support system has been completed, belonging to an advanced support structural system, so that there are stable support points at the bottom of the foundation pit before excavation, and the risk of instability and overturning of the bottom of the foundation pit during the excavation process is greatly reduced.

[0050] In the solution of the present invention, an internal support is arranged at the bottom of the pit, transforming the complex deep geotechnical foundation pit problem into a relatively simple underground structure problem, which can greatly shorten the length of the retaining structure (retaining pile or diaphragm wall). The length of the retaining structure only needs to reach below the bottom support. (For traditional diaphragm walls or support structures, the length reaches 30 - 50 m and the insertion ratio reaches 1.5 - 2 m. In this solution, the length only needs to reach 2 - 3 m below the bottom of the pit, and the total length of the retaining structure can be shortened to about ten to twenty meters), saving the engineering quantity of the retaining structure by several times;

[0051] In the solution of the present invention, the internal support can be designed as a prefabricated internal support frame (i.e., Figures 5 - 7 the vertical support structure shown), and multiple internal support frames are assembled to form a row of internal supports, which are flexible to disassemble and install. Compared with the traditional internal support construction and installation method, it is safer, faster, more efficient, and lower in cost.

[0052] In the solution of the present invention, the internal support can be made of prefabricated steel members in sections and hoisted in sections into the excavated slot openings, which is convenient for construction, has high work efficiency, and low construction cost;

[0053] In the solution of the present invention, the underwater construction method can be adopted, installing the internal support system underwater, excavating underwater. After the foundation pit is excavated to the bottom, the underwater concrete is poured for sealing the bottom, and finally the water in the pit is pumped dry. There is no need for dewatering during the construction process, and the influence on the surrounding ground settlement is smaller;

[0054] In the solution of the present invention, the dewatering construction method can be adopted. The diaphragm wall can participate in water interception. For the lower part of the diaphragm wall participating in water interception, only a 200 - 300 mm thick plain concrete wall (or a mixing soil wall for water interception) needs to be made. The diaphragm wall participating in water interception does not need to participate in the force of the retaining structure, greatly saving the amount of steel bars and concrete of the diaphragm wall and reducing the construction cost. Description of the Drawings

[0055] Figure 1 Schematically showing a three - dimensional view of a deep foundation pit advanced support system according to an embodiment of the present invention;

[0056] Figure 2 Schematically showing a partial three - dimensional view of a deep foundation pit advanced support system according to an embodiment of the present invention;

[0057] Figure 3 Schematically showing a front view of a deep foundation pit advanced support system according to an embodiment of the present invention;

[0058] Figure 4 Schematically showing a partial cross - sectional view of a deep foundation pit advanced support system according to an embodiment of the present invention;

[0059] Figure 5 Schematically showing a three - dimensional view of a deep foundation pit advanced support system according to another embodiment of the present invention;

[0060] Figure 6 Schematic perspective view showing a vertical support structure in a deep foundation pit advanced support system according to another embodiment of the present invention;

[0061] Figure 7 Schematic perspective view showing a vertical support unit in a deep foundation pit advanced support system according to another embodiment of the present invention. Detailed implementation manners

[0062] The content of the present invention will now be described with reference to exemplary embodiments. It should be understood that the described embodiments are only for enabling those of ordinary skill in the art to better understand and thus implement the content of the present invention, rather than implying any limitation to the scope of the present invention.

[0063] As used herein, the term "comprising" and its variants are to be construed as open-ended terms meaning "including but not limited to". The term "based on" is to be construed as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be construed as "at least one embodiment".

[0064] Figure 1 Schematic perspective view showing a deep foundation pit advanced support system according to an embodiment of the present invention; Figure 2 Schematic partial perspective view showing a deep foundation pit advanced support system according to an embodiment of the present invention; Figure 3 Schematic front view showing a deep foundation pit advanced support system according to an embodiment of the present invention; Figure 4 Schematic partial cross-sectional view showing a deep foundation pit advanced support system according to an embodiment of the present invention; Figure 5 Schematic perspective view showing a deep foundation pit advanced support system according to another embodiment of the present invention; Figure 6 Schematic perspective view showing a vertical support structure in a deep foundation pit advanced support system according to another embodiment of the present invention; Figure 7 Schematic perspective view showing a vertical support unit in a deep foundation pit advanced support system according to another embodiment of the present invention. As shown in combination with Figures 1 - 7 In the present invention, the deep foundation pit advanced support system includes:

[0065] A retaining structure, which is supported around the inside of the foundation pit to retain the foundation pit;

[0066] A plurality of vertical support structures, which are supported on the inner walls of the two-side retaining structures at intervals along the length direction of the retaining structure;

[0067] A horizontal support structure, which is arranged at the bottom of the retaining structure and is hermetically connected to the inner walls around the retaining structure, and hermetically closes the bottom of the retaining structure and the bottom of the foundation pit at intervals.

[0068] Further, in the present invention, the retaining structure is a retaining diaphragm wall or retaining piles, and the retaining piles may be a row of pile structures composed of bored cast-in-place piles, diaphragm walls, steel section piles, precast pipe piles and a water-stop curtain integrated together.

[0069] Further, as Figures 1 - 4 shown, according to an embodiment of the present invention, the vertical support structure includes: a capping beam 1, a first support 2, first support steel bars 3, a column 4, column steel bars 5, a second support 7, second support steel bars 8, a third support 10, third support steel bars 11, a bottom support 12, bottom support steel bars 13, a partition formwork 14 and a pouring hole 15;

[0070] A plurality of spaced-apart partition formworks 14 are provided between the first support steel bars 3, the second support steel bars 8, the third support steel bars 11 and the bottom support steel bars 13, and pouring holes 15 are reserved between the respective partition formworks 14. After pouring concrete through the pouring holes 15, connection and fixation are achieved;

[0071] The capping beam 1 is supported on the tops of both sides of the retaining diaphragm wall 9;

[0072] The first support 2, the second support 7, the third support 10 and the bottom support 12 are made by pouring concrete through the first support steel bars 3, the second support steel bars 8, the third support steel bars 11 and the bottom support steel bars 13;

[0073] Both ends of the first support 2 are respectively connected to the capping beams 1 on both sides;

[0074] Both ends of the second support 7, the third support 10 and the bottom support 12 are respectively supported on the inner walls on both sides of the retaining diaphragm wall 9;

[0075] The column steel bars 5 are arranged in the middle of the first support steel bars 3, the second support steel bars 8, the third support steel bars 11 and the bottom support steel bars 13;

[0076] The column 4 is made by pouring concrete with the column steel bars 5.

[0077] Further, as Figure 4 shown, in this embodiment, anti-disengagement steel bars 6 are provided at the upper corners of the joints between the second support 7 and the third support 10 and the inner wall of the retaining structure, and steel section brackets 17 are provided at the lower corners. With such an arrangement, the vertical support structure and the retaining diaphragm wall 9 can be fixed together to prevent the vertical support structure from falling off downward.

[0078] In this embodiment, the first support 2, the column 4, the second support 7, the third support 10, and the bottom support 12 may be a cast-in-place concrete structure, or may adopt a precast concrete structure or a steel section structure.

[0079] In this embodiment, the retaining diaphragm wall 9 is provided with steel bars at the position of the bottom support 12 and above. Below the bottom support 12, it can be a plain concrete wall or a cement-soil wall for water isolation, and the cross-section can be reduced. The retaining structure below the bottom support 12 does not participate in the force-bearing of the retaining structure and only serves as a water isolation function.

[0080] Further, in this embodiment, the partition formwork is a standard unified size member made of wooden formwork, foam formwork, steel formwork, plastic formwork, or aluminum alloy formwork, etc., and can be recycled and reused.

[0081] Further, as Figure 1 and Figure 2 shown, in this embodiment, a horizontal support structure is provided at the bottom of the retaining structure at the bottom of the pit, which is a bottom-sealing concrete slab 16. The bottom-sealing concrete slab 16 and the retaining diaphragm wall 9 form an integral water isolation system, which can cut off groundwater and maintain a dry construction condition inside the foundation pit.

[0082] Further, as Figures 5 - 7 shown, according to another embodiment of the present invention, the vertical support structure is formed by connecting multiple groups of vertical support units;

[0083] Each vertical support unit includes: a horizontal steel support and a vertical connecting steel section 18;

[0084] The horizontal steel support is formed by a steel support 20 and swivel joints 19 provided at both ends of the steel support;

[0085] Multiple horizontal steel supports are arranged at intervals along the vertical direction, and both ends of each horizontal steel support are connected by a vertical connecting steel section 18.

[0086] In this embodiment, each vertical support unit can be detachably connected by bolts through the swivel joints, and each swivel joint 19 can move reciprocally within the steel support 20, that is, the function of telescopic adjustment can be achieved.

[0087] Further, to achieve the above object, the present invention also provides a construction method according to the above deep foundation pit advanced support system, including underwater construction and dewatering construction, including:

[0088] Construct the retaining structure in sections;

[0089] Using a grooving machine, construct a groove structure for supporting the vertical support structure and the horizontal support structure in sections on the inner wall of the retaining structure;

[0090] Install each vertical support structure in sections;

[0091] When the construction is underwater construction, the foundation pit is gradually excavated. After excavating to the bottom of the foundation pit, a horizontal support structure is installed at the bottom of the retaining structure for bottom sealing. After bottom sealing, the water in the foundation pit is pumped dry;

[0092] When the construction is dewatering construction, after the water level in the pit is lowered to a preset distance from the bottom of the foundation pit, the foundation pit is gradually excavated. After the excavation is completed, a horizontal support structure is installed at the bottom of the retaining structure for bottom sealing.

[0093] Furthermore, as Figures 1 - 4 shown, according to an embodiment of the present invention, the vertical support structure includes: a capping beam 1, a first support 2, a first support reinforcement 3, a column 4, a column reinforcement 5, a second support 7, a second support reinforcement 8, a third support 10, a third support reinforcement 11, a bottom support 12, a bottom support reinforcement 13, a partition formwork 14, and a pouring hole 15;

[0094] Between the first support reinforcement 3, the second support reinforcement 8, the third support reinforcement 11, and the bottom support reinforcement 13, a plurality of spaced-apart partition formworks 14 are provided, and pouring holes 15 are reserved between the partition formworks 14. After pouring concrete through the pouring holes 15, connection and fixation are achieved;

[0095] The capping beam 1 is supported on the tops of both sides of the retaining diaphragm wall 9;

[0096] The first support 2, the second support 7, the third support 10, and the bottom support 12 are made by pouring concrete through the first support reinforcement 3, the second support reinforcement 8, the third support reinforcement 11, and the bottom support reinforcement 13;

[0097] Both ends of the first support 2 are respectively connected to the capping beams 1 on both sides;

[0098] Both ends of the second support 7, the third support 10, and the bottom support 12 are respectively supported on the inner walls on both sides of the retaining diaphragm wall 9;

[0099] The column reinforcement 5 is arranged in the middle of the first support reinforcement 3, the second support reinforcement 8, the third support reinforcement 11, and the bottom support reinforcement 13;

[0100] The column 4 is made by pouring concrete with the column reinforcement 5;

[0101] In this embodiment, the installation of each vertical support structure in sections is as follows: installing the first support reinforcement, the second support reinforcement, the third support reinforcement, the bottom support reinforcement, the column reinforcement, and the partition formwork in sections, and reserving pouring holes between the partition formworks;

[0102] Concrete is poured through the pouring holes to construct the supports and columns inside the retaining structure in the foundation pit after completion.

[0103] Furthermore, asFigures 5 - 7 As shown, according to another embodiment of the present invention, the vertical support structure is formed by connecting a plurality of groups of vertical support units;

[0104] Each vertical support unit includes: a transverse steel support and a vertical connecting steel 18;

[0105] The transverse steel support is formed by a steel support 20 and a movable head 19 arranged at both ends of the steel support;

[0106] Multiple transverse steel supports are arranged at intervals along the vertical direction, and both ends of each transverse steel support are connected by a vertical connecting steel 18;

[0107] In this embodiment, the vertical support structures are installed in sections by connecting the horizontal steel supports and the vertical connecting steels 18 to form vertical support units, and connecting multiple groups of vertical support units side by side to form a prefabricated vertical support structure;

[0108] Each vertical support structure is installed in sections, and each vertical support structure is tightly connected to the enclosure structure by adjusting the movable head 19.

[0109] According to the above scheme of the present invention, the scheme of the present invention adopts a trenching machine to construct the internal support, avoiding the traditional method of constructing the internal support while excavating the foundation pit, which has higher construction efficiency and greatly saves construction time.

[0110] The scheme of the present invention utilizes a grooving machine to construct the internal support, adopts assembled finished internal support, can be modularly assembled, and is easy to dismantle.

[0111] A row of internal supports (vertical support structures) provides additional effective support above the bottom of the pit. Before the excavation of the foundation pit, the internal support system has been completed. It is a structural system of advanced support, which ensures that there are stable support points at the bottom of the pit before excavation. The risk of instability and overturning of the pit bottom during the excavation process is greatly reduced.

[0112] The present invention sets an internal support at the bottom of the pit, which transforms the complex rock and soil deep foundation pit problem into a relatively simple underground structure problem, and can greatly shorten the length of the retaining structure (retaining piles or ground-connected walls). The length of the retaining structure only needs to reach below the pit bottom support (the length of the traditional ground-connected wall or supporting structure is 30-50m, and the insertion ratio is 1.5-2m. The length of this solution only needs to reach 2-3m below the pit bottom, and the total length of the retaining structure can be shortened to about ten or twenty meters), which saves the retaining structure engineering workload exponentially;

[0113] The internal support of the present invention can be designed as a prefabricated internal support frame (i.e. Figures 5 - 7 The vertical support structure shown in the figure) is composed of multiple internal support frames, which are assembled to form a row of internal supports. The internal support can be flexibly assembled and disassembled. Compared with the traditional internal support construction and installation method, the internal support is safer, faster, more efficient and less costly.

[0114] In the solution of the present invention, the internal support can be fabricated in precast steel members in sections and hoisted in sections into the excavated slot openings, which is convenient for construction, has high work efficiency and low construction cost;

[0115] The solution of the present invention can adopt the underwater construction method, install the internal support system underwater, excavate underwater. After the foundation pit is excavated to the bottom, the bottom-sealing concrete is poured, and finally the water in the pit is pumped dry. There is no need for dewatering during the construction process, and the impact on the surrounding ground settlement is smaller;

[0116] The solution of the present invention can adopt the dewatering construction method. The diaphragm wall can participate in water interception. For the lower diaphragm wall participating in water interception, only a 200-300 mm thick plain concrete wall (or a mixing soil wall for water interception) needs to be made. The diaphragm wall participating in water interception does not need to participate in the force of the retaining structure, which greatly saves the amount of steel bars and concrete of the diaphragm wall and reduces the cost.

[0117] To make the purpose, technical solution and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only the best embodiments of the present invention, which are only used to explain the present invention and do not limit the protection scope of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0118] Embodiment 1

[0119] Combined with Figures 1 - 4 As shown, a construction method of a deep foundation pit advanced support system, which adopts the underwater construction method, includes the following steps:

[0120] The first step: After completing the "three connections and one leveling" of the site, construct the retaining diaphragm wall 9 in sections;

[0121] The second step: Use the grooving machine to construct the grooving for supporting the internal support in sections;

[0122] The third step: Install the internal support steel bars (the first support steel bar 3, the second support steel bar 8, the third support steel bar 11 and the bottom support steel bar 13), the column steel bars 5 and the partition formwork 14 between each support in sections, and reserve the concrete pouring holes 15;

[0123] The fourth step: Pour concrete from the pouring holes 15, and gradually complete all the internal supports (the first support 2, the second support 7, the third support 10 and the bottom support is 12) and the columns 4 and the capping beam 1 in the foundation pit;

[0124] The fifth step: Adopt the underwater excavation method to gradually excavate the foundation pit, and set the anti-disengagement steel bars 6 and the steel brackets 17 of each support until the bottom of the foundation pit is excavated;

[0125] Step 6: After the foundation pit construction reaches the bottom, pour the bottom sealing concrete slab 16 at the bottom of the retaining structure located at the bottom of the pit;

[0126] Step 7: After the construction of the bottom sealing concrete slab is completed, pump out the water in the pit, and then carry out the construction of the main structure in the pit.

[0127] Embodiment 2

[0128] Combined with Figures 1 - 4 shown, a construction method of an advanced support system for deep foundation pits, which adopts a dewatering construction method and includes the following steps:

[0129] Step 1: After completing the "three connections and one leveling" of the site, construct the retaining diaphragm wall 9 in sections;

[0130] Step 2: Use a grooving machine to construct the grooves for supporting the internal supports in sections;

[0131] Step 3: Install the internal support steel bars (the first support steel bar 3, the second support steel bar 8, the third support steel bar 11, and the bottom support steel bar 13), the column steel bars 5, and the partition templates 14 between each support in sections, and reserve the concrete pouring holes 15;

[0132] Step 4: Pour concrete from the pouring holes 15, and gradually complete the construction of all the internal supports (the first support 2, the second support 7, the third support 10, and the bottom support is 12) and the columns 4 and the capping beam 1 in the foundation pit;

[0133] Step 5: After lowering the water level in the pit 1 m below the bottom of the pit, gradually excavate the foundation pit, and set the anti - detachment steel bars 6 and the steel bracket 17 for each support until the excavation reaches the bottom of the foundation pit;

[0134] Step 6: After the foundation pit construction is completed, pour the bottom sealing concrete slab 16 at the bottom of the retaining structure located at the bottom of the pit, and then carry out the construction of the main structure in the foundation pit.

[0135] Embodiment 3

[0136] Combined with Figures 5 - 7 shown, a construction method of an advanced support system for deep foundation pits, which adopts an underwater construction method and includes the following steps:

[0137] Step 1: After completing the "three connections and one leveling" of the site, construct the retaining diaphragm wall 9 in sections;

[0138] Step 2: Use a grooving machine to construct the grooves for supporting the internal supports in sections;

[0139] Step 3: Install a set of internal support frames (the set of internal support frames is pre - fabricated) in sections, and install multiple sets of internal support frames in place to form a row of internal supports;

[0140] Step 4: Gradually excavate the foundation pit by means of underwater excavation, and adjust the flexible joints 19 of each internal support to make the internal support closely fit on the retaining diaphragm wall 9, and connect them with bolts or post-implanted bars.

[0141] Step 5: After the foundation pit construction reaches the bottom of the pit, pour the bottom-sealing concrete slab 16 at the bottom of the pit.

[0142] Step 6: After the construction of the bottom-sealing concrete slab is completed, pump out the water in the pit, and then carry out the construction of the main structure in the pit.

[0143] Embodiment 4

[0144] Combined with Figures 5 - 7 As shown, a deep foundation pit advanced support system and its construction method. This construction method adopts the dewatering construction method, including the following steps:

[0145] Step 1: After completing the "three connections and one leveling" of the site, construct the retaining diaphragm wall 9 in sections.

[0146] Step 2: Use a grooving machine to construct the grooves for supporting the internal support in sections.

[0147] Step 3: Install a set of internal support frames (the set of internal support frames are prefabricated) in sections, and install multiple sets of internal support frames in place to form a row of internal supports.

[0148] Step 4: After lowering the water level in the pit 1 m below the bottom of the pit, gradually excavate the foundation pit, adjust the flexible joints 19 to make the internal support closely fit with the retaining diaphragm wall 9, and connect the internal support and the retaining structure with bolts or post-implanted bars until the excavation reaches the bottom of the foundation pit.

[0149] Step 5: After the foundation pit construction is completed, pour the bottom-sealing concrete slab 16 at the bottom of the retaining structure at the bottom of the pit, and carry out the construction of the main structure in the foundation pit.

[0150] The above description is only the preferred embodiment of the present application and the explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

[0151] It should be understood that the magnitudes of the sequence numbers of the steps in the content and implementation manners of the present invention do not absolutely mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiment of the present invention.

Claims

1. Advanced support system for deep foundation pits, characterized in that, Comprising: A retaining structure, which is supported around the foundation pit to retain the foundation pit; A plurality of vertical support structures, along the length direction of the retaining structure, each vertical support structure is supported on the inner walls of the two-side retaining structures at intervals; A horizontal support structure, which is arranged at the bottom of the retaining structure, is hermetically connected to the inner walls around the retaining structure, and hermetically separates and closes the bottom of the retaining structure from the bottom of the foundation pit.

2. The advanced support system for deep foundation pits according to claim 1, wherein, The retaining structure is a retaining diaphragm wall or a retaining pile.

3. The advanced support system for deep foundation pits according to claim 1, characterized in that, The vertical support structure includes: a capping beam, a first support, first support steel bars, a column, column steel bars, a second support, second support steel bars, a third support, third support steel bars, a bottom support, bottom support steel bars, a partition formwork, and a pouring hole; A plurality of partition formworks arranged at intervals are provided between the first support steel bars, the second support steel bars, the third support steel bars, and the bottom support steel bars, and pouring holes are reserved between the partition formworks, and connection and fixation are achieved after pouring concrete through the pouring holes; The capping beam is supported on the tops of both sides of the retaining structure; The first support, the second support, the third support, and the bottom support are made by pouring concrete through the first support steel bars, the second support steel bars, the third support steel bars, and the bottom support steel bars; Both ends of the first support are respectively connected to the capping beams on both sides; Both ends of the second support, the third support, and the bottom support are respectively supported on the inner walls of both sides of the retaining structure; The column steel bars are arranged in the middle of the first support steel bars, the second support steel bars, the third support steel bars, and the bottom support steel bars; The column is made by pouring concrete with the column steel bars.

4. The advanced support system for deep foundation pits according to claim 3, characterized in that, At the upper corner of the connection between the second support and the third support and the inner wall of the retaining structure, anti-disengagement steel bars are provided, and at the lower corner, a steel section bracket is provided.

5. The advanced support system for deep foundation pits according to claim 3, characterized in that, The partition formwork is a wooden formwork, a foam formwork, a steel formwork, a plastic formwork, or an aluminum alloy formwork.

6. The advanced support system for deep foundation pits according to claim 1, characterized in that, The vertical support structure is formed by connecting multiple groups of vertical support units; Each of the vertical support units includes: a horizontal steel support and a vertical connecting steel section; The horizontal steel support is formed by a steel support and swivel joints arranged at both ends of the steel support; Multiple horizontal steel supports are arranged at intervals along the vertical direction, and both ends of each horizontal steel support are connected by the vertical connecting steel sections.

7. The construction method of the advanced support system for deep foundation pits according to any one of claims 1-6, including underwater construction and dewatering construction, is characterized in that, Comprising: Constructing the retaining structure in sections; Using a grooving machine, constructing a groove structure for supporting the vertical support structure and the horizontal support structure on the inner wall of the retaining structure in sections; Installing each vertical support structure in sections; When the construction is underwater construction, gradually excavate the foundation pit. After excavating to the bottom of the foundation pit, install a horizontal support structure at the bottom of the retaining structure for bottom sealing. After bottom sealing, pump out the water in the foundation pit; When the construction is dewatering construction, lower the water level in the pit to a preset distance from the bottom of the foundation pit, then gradually excavate the foundation pit. After excavation is completed, install a horizontal support structure at the bottom of the retaining structure for bottom sealing.

8. The construction method of the advanced support system for deep foundation pits according to claim 7, characterized in that, The vertical support structure includes: a capping beam, a first support, first support reinforcement bars, columns, column reinforcement bars, a second support, second support reinforcement bars, a third support, third support reinforcement bars, a bottom support, bottom support reinforcement bars, partition formworks, and casting holes; A plurality of partition formworks arranged at intervals are provided between the first support reinforcement bars, the second support reinforcement bars, the third support reinforcement bars, and the bottom support reinforcement bars. Pouring holes are reserved between the partition formworks, and connection and fixation are achieved after pouring concrete through the pouring holes; The capping beam is supported on the tops of both sides of the retaining structure; The first support, the second support, the third support, and the bottom support are made by pouring concrete through the first support reinforcement bars, the second support reinforcement bars, the third support reinforcement bars, and the bottom support reinforcement bars; Both ends of the first support are respectively connected to the capping beams on both sides; Both ends of the second support, the third support, and the bottom support are respectively supported on the inner walls on both sides of the retaining structure; The column reinforcement bars are arranged in the middle of the first support reinforcement bars, the second support reinforcement bars, the third support reinforcement bars, and the bottom support reinforcement bars; The columns are made by pouring concrete with the column reinforcement bars; The method of installing each vertical support structure in sections is as follows: install the first support reinforcement bars, the second support reinforcement bars, the third support reinforcement bars, the bottom support reinforcement bars, the column reinforcement bars, and the partition formworks in sections, and reserve pouring holes between the partition formworks; Pour concrete through the pouring holes to complete the supports and columns inside the retaining structure in the foundation pit after construction; 9. The construction method of the advanced support system for deep foundation pits according to claim 7, characterized in that, The vertical support structure is formed by connecting multiple groups of vertical support units; Each of the vertical support units includes: a horizontal steel support and a vertical connecting section steel; The horizontal steel support is formed by a steel support and swivel joints arranged at both ends of the steel support; Multiple horizontal steel supports are arranged at intervals along the vertical direction, and both ends of each horizontal steel support are connected by the vertical connecting section steel; The method of installing each vertical support structure in sections is as follows: connect the horizontal steel support and the vertical connecting section steel to form a vertical support unit, and connect multiple groups of vertical support units side by side to form a prefabricated vertical support structure; Install each vertical support structure in sections, and make each vertical support structure closely connected to the retaining structure by adjusting the swivel joints.

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