Prefabricated underground structure cover-excavation reverse construction method and prefabricated underground structure

Abstract

The present invention provides a method for the reverse construction of an assembled underground structure with cover and excavation, and an assembled underground structure, so as to solve the problem that it is difficult to construct an assembled structure with the reverse construction method with cover and excavation, and reduce the construction period of the assembled underground structure, and relates to the field of underground structure engineering. A method for the reverse construction of an assembled underground structure with cover and excavation, comprising: dividing the ground-connected wall of the underground structure from top to bottom into a enclosure section, a side wall section, and a cast-in-place embedded section in sequence with the upper edge of the top plate of the underground structure and a certain distance below the bottom plate as a dividing line; constructing a continuous wall installation groove; first detachably installing the prefabricated enclosure section prefabricated block on the side wall section prefabricated block, and then installing the side wall section prefabricated block in the continuous wall installation groove, adjusting the installation position of the side wall section prefabricated block to meet the requirements, and then fixing the side wall section prefabricated block in the continuous wall installation groove, pouring concrete downward through the vertical through holes on the side wall section prefabricated block and the prefabricated enclosure section prefabricated block, and then pouring the connecting head. The present invention simplifies construction and reduces costs.

Description

Technical Field

[0001] The invention relates to the field of underground structure engineering, and in particular to a cover-excavation reverse construction method for an assembled underground structure and an assembled underground structure. Background Art

[0002] In underground structural projects, such as subway stations, cast-in-place structures or prefabricated structures are mainly used. Among them, prefabricated structures have the advantages of being environmentally friendly, saving resources, shortening construction time, and reducing noise pollution, and are increasingly used in projects.

[0003] The cover-and-cut reverse construction method is a common method for underground engineering construction. The construction sequence of the cover-and-cut reverse construction method is to first construct a continuous wall, then excavate the earthwork and construct the structure from top to bottom, and finally form a complete permanent structure. Since the cover-and-cut reverse construction method adopts excavation and construction from top to bottom, the load on the side wall of the main structure will gradually increase as the construction progresses, and the side wall position will easily change. For prefabricated underground structures, since the main parts of the structure are prefabricated and the size is fixed, once the side wall position changes, it will cause difficulties in the subsequent prefabricated structure construction. Therefore, the current prefabricated underground structure mainly adopts the sequential construction method of first constructing the bottom plate and then constructing the middle plate and the top plate. For example: the Chinese patent application number 202210883520.6 discloses a permanent and temporary combined prefabricated station and its construction method; the Chinese patent application number 202210740080.9 discloses a construction method of a prefabricated subway station with enclosure and main permanent and temporary combination. This method requires the establishment of a large number of temporary supports, which has an adverse effect on the construction period. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for constructing an assembled underground structure by cover-excavation and reverse construction and an assembled underground structure, so as to solve the problem that the assembled structure is difficult to construct by the cover-excavation and reverse construction method and reduce the construction period of the assembled underground structure.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for reverse construction of an assembled underground structure with cover and excavation, comprising the following steps:

[0006] The ground-connected wall of the underground structure is divided into a enclosure section, a side wall section and a cast-in-place embedded section from top to bottom in sequence, with the upper edge of the top plate of the underground structure and a certain distance below the bottom plate as the dividing line, and the enclosure section prefabricated blocks and the side wall section prefabricated blocks are prefabricated according to the height of the enclosure section and the side wall section, and the side wall section prefabricated blocks and the enclosure section prefabricated blocks are both reserved with vertical through holes for casting the cast-in-place embedded section;

[0007] Construction of continuous wall installation groove;

[0008] First, the prefabricated enclosure section prefabricated block is detachably installed on the side wall section prefabricated block, and then the side wall section prefabricated block is installed in the continuous wall installation groove. After the installation position of the side wall section prefabricated block is adjusted to meet the requirements, the side wall section prefabricated block is fixed in the continuous wall installation groove, and concrete is poured downward through the vertical through holes on the side wall section prefabricated block and the prefabricated enclosure section prefabricated block to form a cast-in-place embedded section under the side wall section prefabricated block to embed the prefabricated enclosure section prefabricated block, and then the connectors between the side wall section prefabricated blocks and the prefabricated enclosure section prefabricated blocks are poured to splice the side wall section and the enclosure section, and then the gap between the side wall section and the enclosure section and the groove wall of the continuous wall installation groove is grouting or mud improvement and solidification is performed to complete the ground-connected wall construction;

[0009] Construct the center column hole, lower the center column and pile foundation steel cage, insert the center column into the center column pile foundation steel cage, and then pour the pile foundation concrete;

[0010] Excavate to the top plate and the bottom of the top longitudinal beam, install the prefabricated steel cage of the crown beam, the prefabricated top plate longitudinal beam, the prefabricated top plate, the crown beam, the prefabricated top plate longitudinal beam superposition layer, the prefabricated top plate superposition layer and all the connection nodes, and complete the top plate construction;

[0011] Excavate to the bottom of the middle plate and middle longitudinal beam, install the prefabricated middle longitudinal beam and prefabricated middle plate, cast the prefabricated middle longitudinal beam superposition layer, prefabricated middle plate superposition layer and all connection nodes together to complete the middle plate construction;

[0012] Excavate to the base, construct grounding, bottom plate cushion and waterproof layer, install prefabricated steel cage for bottom plate and bottom longitudinal beam, cast the cast-in-place structure of bottom plate and bottom longitudinal beam, and complete the bottom plate construction

[0013] The underground structure is covered with soil, and the retaining section of the ground-connected wall is removed and backfilled.

[0014] Furthermore, annular steel cages are provided at the connection points of the middle longitudinal beam on the center column and at the connection points of the prefabricated steel cages of the bottom longitudinal beams, the connecting bars of the prefabricated middle longitudinal beams are connected to the annular steel cages at the connection points of the middle longitudinal beams, and the steel bars of the prefabricated steel cages of the bottom longitudinal beams are connected to the annular steel cages at the connection points of the prefabricated steel cages of the bottom longitudinal beams.

[0015] Furthermore, anti-shear rings are provided at the connection points of the middle longitudinal beam on the center column and at the connection points of the prefabricated steel cage of the bottom longitudinal beam.

[0016] Furthermore, the step of installing the side wall segment prefabricated block in the continuous wall installation groove and adjusting the installation position of the side wall segment prefabricated block to meet the requirements includes:

[0017] Preliminary installation: a lifting device is set according to the installation position of the side wall segment prefabricated block, the lifting device includes a bracket, a vertical adjustment device, a horizontal adjustment device and a lifting device, the horizontal adjustment device is installed on the bracket, the vertical adjustment device is installed on the horizontal adjustment device, and the lifting device is installed on the vertical adjustment device. During installation, the side wall segment prefabricated block is preliminarily installed at the installation position in the continuous wall installation groove by using the lifting device through the lifting rope;

[0018] Precise position adjustment: a plurality of pushing mechanisms arranged along the height direction of the continuous wall installation groove are respectively arranged on both sides of the two ends of the side wall section prefabricated block, and a plurality of distance measuring devices arranged along the height direction of the continuous wall installation groove are arranged on one side of the two ends of the side wall section prefabricated block. During precise adjustment, the horizontal position between the side wall section prefabricated block and the previous side wall section prefabricated block is accurately adjusted by the horizontal adjustment device to meet the requirements, and the elevation of the side wall section prefabricated block is accurately adjusted by the vertical adjustment device to meet the requirements, and the distance measuring device is used to measure the distance between the different height positions at the two ends of the side wall section prefabricated block and the groove wall of the continuous wall installation groove, and then the pushing mechanism is used to adjust the distance between the different height positions at the two ends of the side wall section prefabricated block and the groove wall of the continuous wall installation groove according to the distance data between the different height positions at the two ends of the side wall section prefabricated block and the groove wall of the continuous wall installation groove measured by the distance measuring device, so that the plane positioning and verticality of the side wall section prefabricated block meet the requirements.

[0019] Furthermore, the vertical adjustment device and the horizontal adjustment device are both electric screw slides.

[0020] Furthermore, the prefabricated middle longitudinal beam and the prefabricated middle plate are hoisted and installed by means of hanging rails arranged on the prefabricated top plate; the prefabricated steel cage of the bottom plate and the prefabricated steel cage of the bottom longitudinal beam are hoisted and installed by means of hanging rails arranged on the prefabricated middle plate.

[0021] The prefabricated underground structure is constructed by the above-mentioned prefabricated underground structure cover-excavation reverse construction method.

[0022] The beneficial effects of the present invention are as follows: the cover-excavation reverse construction method of the assembled underground structure and the assembled underground structure of the present invention divide the ground-connected wall of the underground structure from top to bottom into a enclosure section, a side wall section and a cast-in-place embedded section in sequence at a certain distance below the upper edge of the top plate of the underground structure and the bottom plate, and then prefabricate the corresponding side wall section prefabricated blocks and enclosure section prefabricated blocks according to the height of the enclosure section and the side wall section, and then adjust and fix the position of the side wall section prefabricated blocks according to the installation position, and then pour concrete downward through the through holes of the side wall section prefabricated blocks and the enclosure section prefabricated blocks to form a cast-in-place embedded section, so that the side wall section prefabricated blocks are fixed on the cast-in-place embedded section, and then cast the side wall section prefabricated blocks in a cast-in-place manner. The joints between the prefabricated blocks and the prefabricated enclosure sections are finally constructed by grouting or mud improvement and solidification of the gaps between the side wall sections and the enclosure sections and the groove walls of the continuous wall installation grooves. This ensures the position accuracy of the side wall sections that will serve as the side walls of the underground structure in the later stage, and will not change. The formed side wall sections are well waterproof. Therefore, the prefabricated underground structure can be constructed by the top-down cover-excavation reverse construction method, and the top plate and the middle plate can be used as supports. The prefabricated composite components of the top plate and the middle plate do not need to be divided into two types: support and main structure plates. Only one type of prefabricated composite plate is needed, which reduces the types of prefabricated components, simplifies construction, and reduces costs.

[0023] After this construction method is implemented and the reverse construction method is adopted, all prefabricated composite structures are constructed in the excavation stage. The ground at the excavation location can be used as a ground membrane or a low support can be set up to bear the construction load. The prefabricated components are simple to bear force, and the reinforcement can be properly optimized. There is no need to set a corbel at the connection between the plate and the ground-connected wall. The size and weight of the prefabricated components can also be further optimized, which is more conducive to construction and cost control.

[0024] After this construction method is implemented and the reverse construction method is adopted, the connection nodes of each layer are simultaneously bundled and poured at one time, which greatly reduces the number of steel bar joints, simplifies the construction process, and strengthens the integrity of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figures 1 to 4 It is a construction schematic diagram of the method of the present invention;

[0026] Figure 5 It is a cross-sectional view of the precast block of the side wall section;

[0027] Figure 6 It is the cross-section of the precast block of the enclosure section;

[0028] Figure 7 It is a cross-sectional view of the column position of the assembled underground structure of the present invention;

[0029] Figure 8 It is a cross-sectional view of the assembled underground structure column of the present invention;

[0030] Fig. 9It is a plan layout diagram of the top plate of the assembled underground structure of the present invention;

[0031] Fig.10 It is a plan view of the middle plate of the assembled underground structure of the present invention;

[0032] Fig.11 is a mid-span longitudinal section of the assembled underground structure of the present invention;

[0033] Fig.12 It is a longitudinal section view of the column position of the assembled underground structure of the present invention;

[0034] Fig.13 It is a schematic diagram of the connection structure between the prefabricated middle longitudinal beam and the middle column;

[0035] Fig.14 This is a schematic diagram of the installation construction of the prefabricated blocks of the side wall section;

[0036] Fig.15 yes Fig.14 Section view along AA;

[0037] As shown in the figure: enclosure section 1, side wall section 2, cast-in-place embedded section 3, continuous wall installation groove 4, vertical through hole 5, center column 6, lifting device 7, pushing mechanism 8, distance measuring device 9, enclosure section precast block 11, side wall section precast block 21, precast top plate longitudinal beam 22, crown beam precast steel cage 23, precast top plate 24, precast middle plate 25, precast middle longitudinal beam 26, bottom longitudinal beam precast steel cage 27, bottom plate precast steel cage 28, bottom plate 29, bottom longitudinal beam 30, annular steel cage 61, shear ring 62, bracket 71, vertical adjustment device 72, horizontal adjustment device 73, lifting device 74, support frame 81. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0039] like Figures 1 to 12 As shown, the cover-excavation reverse construction method of the assembled underground structure of the present invention comprises the following steps:

[0040] Step 1: Using the upper edge of the top plate of the underground structure and a certain distance below the bottom plate as the dividing line, the ground-connected wall of the underground structure is divided into a retaining section 1, a side wall section 2 and a cast-in-place embedded section 3 from top to bottom in sequence, and according to the heights of the retaining section 1 and the side wall section 2, a retaining section prefabricated block 11 and a side wall section prefabricated block 21 of corresponding heights are prefabricated, and both the side wall section prefabricated block 21 and the retaining section prefabricated block 11 are reserved with vertical through holes 5 for casting the cast-in-place embedded section;

[0041] Step 2: construct the continuous wall installation groove 4;

[0042] Step 3: Install the cast-in-place embedded steel cage in the continuous wall installation groove 4, and detachably install the prefabricated enclosure section prefabricated block 11 on the side wall section prefabricated block 21, which can be specifically connected by bolts, clamping, etc., and then install the side wall section prefabricated block 21 in the continuous wall installation groove 4, adjust the position of the side wall section prefabricated block 21 according to the installation position, and fix the side wall section prefabricated block 21 in the continuous wall installation groove 4 after it meets the requirements, and then fix the side wall section prefabricated block 21 in the continuous wall installation groove 4, and fix the side wall section prefabricated block 21 and Concrete is poured downwardly through the vertical through hole 5 on the precast enclosure section precast block 11 to form a cast-in-place embedded section 3 below the side wall section precast block 21 to embed the precast enclosure section precast block 11, and then the joints between the side wall section precast blocks 21 and the precast enclosure section precast blocks 11 are poured to form the side wall section 2 and the enclosure section 1, and then grouting or mud improvement and solidification is performed on the gap between the side wall section 2 and the enclosure section 1 and the groove wall of the continuous wall installation groove 4 to complete the ground-connected wall construction;

[0043] Step 4: construct the center column hole, lower the center column 6 and the pile foundation steel cage. The center column 6 is generally a steel tube (circular tube or square tube) concrete column. When constructing the center column from the ground, complete the concrete pouring in the center column and reserve the top and top longitudinal beam connection steel bars. The center column is inserted into the pile foundation steel cage under the bottom plate of the main structure, and then the pile foundation concrete is poured. In this way, the center column can bear the deadweight and construction load of the upper structure during the reverse construction process during the construction stage, and can also be used as a station pull-out pile in the permanent force condition after the construction is completed;

[0044] Step 5: excavate to the bottom of the top plate and top longitudinal beam, install the crown beam prefabricated steel cage 23, the prefabricated top plate longitudinal beam 22, the prefabricated top plate 24, the crown beam, the prefabricated top plate longitudinal beam superposition layer, the prefabricated top plate superposition layer, the crown beam and the prefabricated top plate connection point, the prefabricated top plate longitudinal beam and the center column connection point, the crown beam and the side wall section connection point and other connection nodes, and cast in situ to complete the top plate construction, so that the top plate forms the first support of the continuous wall;

[0045] Step 6: excavate to the bottom of the middle plate and the middle longitudinal beam, install the prefabricated middle longitudinal beam 26 and the prefabricated middle plate 25, cast the prefabricated middle longitudinal beam superposition layer, the prefabricated middle plate superposition layer and the corresponding connection nodes between the above components together, complete the middle plate construction, and make the middle plate form the middle support of the continuous wall;

[0046] Step 7: excavate to the base, construct grounding, bottom plate cushion and waterproof layer, install prefabricated bottom plate steel cage 28 and bottom longitudinal beam prefabricated steel cage 27, cast bottom 29 and bottom longitudinal beam 30 cast-in-place structure, and complete the bottom plate construction;

[0047] Step 8: Cover the underground structure with soil, remove the enclosure section 1 of the ground-connected wall and backfill.

[0048] Among them, a certain distance below the bottom plate is the dividing line, and the distance can be set according to actual conditions so as to fix the prefabricated blocks 11 of the enclosure section. In the embodiment of the present invention, the dividing line is 1.5 meters below the bottom plate.

[0049] In the above steps, step 2 and step 4 can be performed simultaneously or step 4 can be performed first.

[0050] The cover-excavation reverse construction method of the prefabricated underground structure of the present invention divides the ground-connected wall of the underground structure from top to bottom into a retaining section 1, a side wall section 2 and a cast-in-place embedded section 3 at the upper edge of the top plate of the underground structure and a certain distance below the bottom plate, and then prefabricates the corresponding side wall section prefabricated blocks 21 and the retaining section prefabricated blocks 11 according to the height of the retaining section 1 and the side wall section 2. In this way, during construction, the side wall section spliced ​​by the side wall section prefabricated blocks 21 is not segmented in the height direction. During construction, the method first adjusts and fixes the position of the side wall segment prefabricated block 21 according to the installation position, and then pours concrete downward through the through holes 5 of the side wall segment prefabricated block 21 and the enclosure segment prefabricated block 11 to form a cast-in-place embedded section 3, so that the side wall segment prefabricated block 21 is fixed on the cast-in-place embedded section 3, and then casts the connectors between the side wall segment prefabricated blocks 21 and the prefabricated enclosure segment prefabricated blocks 11 in a cast-in-place manner, and finally injects grout or mud to improve and solidify the gaps between the side wall segment 2 and the enclosure segment 1 and the groove wall of the continuous wall installation groove 4, so as to ensure the position accuracy of the side wall segment that will serve as the side wall of the underground structure in the later stage, and will not change, and the formed side wall segment is waterproof, so that the assembled underground structure can be constructed by the top-down cover-excavation reverse construction method, and the top plate and the middle plate can be used as supports at the same time. The prefabricated composite components of the top plate and the middle plate do not need to be divided into two types: support and main structure plates. Only one type of prefabricated composite plate is needed, which reduces the types of prefabricated components, simplifies construction, and reduces costs (see Fig. 9 , Fig.10 ). In addition, after the method is implemented and the reverse construction method is adopted, all prefabricated composite structures are constructed in the excavation stage. The ground at the excavation location can be used as a ground membrane or a low support can be set up to bear the construction load. Therefore, the prefabricated components are simple to bear force and the reinforcement can be properly optimized. There is no need to set a corbel at the connection between the plate and the ground-connected wall. The size and weight of the prefabricated components can also be further optimized, which is more conducive to construction convenience and cost control; the connection nodes of each layer are bundled and constructed at the same time, and the pouring construction is carried out at one time, that is, there is no need to construct one part first, and the other part needs to be constructed after the lower structure is completed, which greatly reduces the steel bar joints, simplifies the construction process, and strengthens the integrity of the structure.

[0051] The specific method of pouring the cast-in-place embedded section 3 is to extend the concrete conduit into the through hole 5, so that the lower end of the concrete conduit extends into the bottom of the continuous wall installation groove 4, and move upward while pouring concrete, so that the mud in the continuous wall installation groove 4 can be discharged from the through hole 5. The side wall section prefabricated block 21 and the enclosure section prefabricated block 11 are both reserved with vertical through holes 5 for pouring the cast-in-place embedded section, which can also reduce the dead weight of the prefabricated blocks.

[0052] In order to ensure the connection strength and rigidity between the longitudinal beam and the center column, the connection point of the middle longitudinal beam on the center column 6 and the connection point of the prefabricated steel cage 27 of the bottom longitudinal beam are sleeved with an annular steel cage 61, and the connecting ribs of the prefabricated middle longitudinal beam 26 are connected to the annular steel cage 61 at the connection point of the middle longitudinal beam (see Fig.13 ), the steel bars of the bottom longitudinal beam prefabricated steel cage 27 are connected to the annular steel cage 61 at the connection point of the bottom longitudinal beam prefabricated steel cage. Further, the connection point of the middle longitudinal beam on the center column 6 and the connection point of the bottom longitudinal beam prefabricated steel cage are both provided with a shear ring 62 to enhance the shear resistance at the connection point.

[0053] The side wall segment prefabricated block 21 can be directly adjusted by a lifting device, but due to the limited adjustment accuracy of the conventional lifting device, it is not convenient to adjust the position of the side wall segment prefabricated block 21, and it is difficult to ensure the flatness of the side wall segment prefabricated block 21 and the side wall segment prefabricated block 21 installed previously. Fig.14 , Fig.15 As shown, in order to improve the installation efficiency of the side wall segment prefabricated block 21 and ensure the installation accuracy, in the embodiment of the present invention, the side wall segment prefabricated block 21 is installed in the continuous wall installation groove 4, and the installation position of the side wall segment prefabricated block 21 is adjusted to meet the requirements. Specifically, the following method is adopted:

[0054] A. Preliminary installation: a lifting device 7 is set according to the installation position of the side wall segment prefabricated block 21, the lifting device 7 comprises a bracket 71, a vertical adjustment device 72, a horizontal adjustment device 73 and a lifting device 74, the horizontal adjustment device 73 is installed on the bracket 71, the vertical adjustment device 72 is installed on the horizontal adjustment device 73, and the lifting device 74 is installed on the vertical adjustment device 72. During installation, the lifting device 74 is used to preliminarily install the side wall segment prefabricated block 21 at the installation position in the continuous wall installation groove 4 through the lifting rope, that is, the position of the side wall segment prefabricated block 21 is roughly within the installation size requirement range;

[0055] B. Precise position adjustment: A plurality of jacking mechanisms 8 arranged along the height direction of the continuous wall installation groove 4 are respectively arranged on both sides of the two ends of the side wall section prefabricated block 21, and a plurality of distance measuring devices 9 arranged along the height direction of the continuous wall installation groove 4 are arranged on one side of the two ends of the side wall section prefabricated block 21. When the position is precisely adjusted, the horizontal position between the side wall section prefabricated block 21 and the previous side wall section prefabricated block 21 is precisely adjusted by the horizontal adjustment device 73 to meet the requirements, and the elevation of the side wall section prefabricated block 21 is precisely adjusted by the vertical adjustment device 72 to meet the requirements. The distance measuring device 9 is used to measure the distance between the different height positions at both ends of the side wall section prefabricated block 21 and the groove wall of the continuous wall installation groove 4. According to the distance data between the different height positions at both ends of the side wall section prefabricated block 21 and the groove wall of the continuous wall installation groove 4 measured by the distance measuring device 9, the jacking mechanism 8 at each position is extended, retracted or stopped to adjust the distance between the different height positions at both ends of the side wall section prefabricated block 21 and the groove wall of the continuous wall installation groove 4, so that the side wall section prefabricated block 21 can be swung, and then the plane positioning and verticality of the side wall section prefabricated block 21 meet the requirements. Finally, the side wall section prefabricated block 21 can be clamped and fixed in the continuous wall installation groove 4 by the jacking mechanism 8 on both sides for subsequent construction.

[0056] Specifically, the vertical adjustment device 72 and the horizontal adjustment device 73 are both electric screw slides, which can also be pneumatic slides or hydraulic slides, or gear rack linear movement mechanisms, etc.; the push mechanism 8 can be a cylinder, a hydraulic cylinder or an electric push rod, etc.;

[0057] In order to facilitate construction and reuse, the distance measuring device 9 and the pushing mechanism 8 can be installed on the support frame 81, and then set in the continuous wall installation groove 4 by the support frame 81 being deeply inserted into the continuous wall installation groove 4.

[0058] In order to facilitate the installation of the prefabricated middle longitudinal beam 26, the prefabricated middle plate 25, the bottom plate prefabricated steel cage 28 and the bottom longitudinal beam prefabricated steel cage 27, in the embodiment of the present invention, the prefabricated middle longitudinal beam 26 and the prefabricated middle plate 25 are hoisted and installed by means of the hanging rails provided on the prefabricated top plate 24; the bottom plate prefabricated steel cage 28 and the bottom longitudinal beam prefabricated steel cage 27 are hoisted and installed by means of the hanging rails provided on the prefabricated middle plate 25. In order to facilitate the installation of the hanging rails, the prefabricated middle plate 25 and the prefabricated top plate 24 can be pre-embedded with corresponding hanging rail installation connectors.

[0059] The present invention also provides an assembled underground structure, which is constructed by the above-mentioned assembled underground structure cover-excavation reverse construction method. The assembled underground structure constructed by the above-mentioned method does not need to be divided into two types of support and main structure plates, and only one type of prefabricated composite plate is needed, which reduces the types of prefabricated components, simplifies construction, and reduces costs. In addition, the connection nodes of each layer are bundled and constructed at the same time, and the casting construction is carried out at one time, that is, there is no need to construct one part first, and the other part needs to be constructed after the construction of the lower structure is completed, which greatly reduces the steel bar joints of the underground structure, simplifies the construction process, and strengthens the integrity of the structure.

Claims

1. A method for the reverse construction of an assembled underground structure by cover-excavation, characterized in that: The following steps are involved: The ground-connected wall of the underground structure is divided into a retaining section (1), a side wall section (2) and a cast-in-place embedded section (3) from top to bottom in sequence, with the upper edge of the top plate of the underground structure and a certain distance below the bottom plate as the dividing line, and the retaining section prefabricated blocks (11) and the side wall section prefabricated blocks (21) are prefabricated according to the heights of the retaining section (1) and the side wall section (2), and the side wall section prefabricated blocks (21) and the retaining section prefabricated blocks (11) are both reserved with vertical through holes (5) for casting the cast-in-place embedded section; Constructing the continuous wall installation groove (4); The cast-in-place embedded steel cage is installed in the continuous wall installation groove (4), the prefabricated enclosure section prefabricated block (11) is detachably installed on the side wall section prefabricated block (21), and then the side wall section prefabricated block (21) is installed in the continuous wall installation groove (4), and the installation position of the side wall section prefabricated block (21) is adjusted to meet the requirements, and then the side wall section prefabricated block (21) is fixed in the continuous wall installation groove (4), and the vertical positions of the side wall section prefabricated block (21) and the prefabricated enclosure section prefabricated block (11) are connected to each other. Concrete is poured downwardly through the through hole (5) to form a cast-in-place embedded section (3) below the side wall section prefabricated block (21) to embed the prefabricated enclosure section prefabricated block (11), and then the connectors between the side wall section prefabricated blocks (21) and the prefabricated enclosure section prefabricated blocks (11) are poured to form the side wall section (2) and the enclosure section (1), and then grouting or mud improvement and solidification is performed on the gaps between the side wall section (2) and the enclosure section (1) and the groove wall of the continuous wall installation groove (4), thereby completing the ground-connected wall construction; Constructing the center column hole, lowering the center column (6) and the pile foundation steel cage, inserting the center column (6) into the center column pile foundation steel cage, and then pouring the pile foundation concrete; Excavate to the top plate and the bottom of the top longitudinal beam, install the crown beam prefabricated steel cage (23), the prefabricated top plate longitudinal beam (22), the prefabricated top plate (24), the crown beam, the prefabricated top plate longitudinal beam superposition layer, the prefabricated top plate superposition layer and each connection node together, and complete the top plate construction; Excavate to the bottom of the middle plate and the middle longitudinal beam, install the prefabricated middle longitudinal beam (26) and the prefabricated middle plate (25), cast the prefabricated middle longitudinal beam superimposed layer, the prefabricated middle plate superimposed layer and each connection node together, and complete the construction of the middle plate; Excavate to the base, construct grounding, bottom slab cushion and waterproof layer, install prefabricated bottom slab steel cage (28) and bottom longitudinal beam prefabricated steel cage (27), cast the bottom slab and bottom longitudinal beam cast-in-place structure, and complete the bottom slab construction The underground structure is covered with soil, and the retaining section (1) of the ground-connected wall is removed and backfilled.

2. The method for constructing an assembled underground structure by cover-excavation and reverse construction as claimed in claim 1, characterized in that: An annular steel cage (61) is provided at the connection point of the middle longitudinal beam on the center column (6) and at the connection point of the prefabricated steel cage (27) of the bottom longitudinal beam; the connection bars of the prefabricated middle longitudinal beam (26) are connected to the annular steel cage (61) at the connection point of the middle longitudinal beam; and the steel bars of the prefabricated steel cage (27) of the bottom longitudinal beam are connected to the annular steel cage (61) at the connection point of the prefabricated steel cage of the bottom longitudinal beam.

3. The method for constructing an assembled underground structure by cover-excavation and reverse construction as claimed in claim 1 or 2, characterized in that: Anti-shear rings (62) are provided at the connection points of the middle longitudinal beam on the middle column (6) and at the connection points of the prefabricated steel cage of the bottom longitudinal beam.

4. The method for constructing an assembled underground structure by cover-excavation and reverse construction as claimed in claim 1, characterized in that: The step of installing the side wall segment prefabricated block (21) in the continuous wall installation groove (4) and adjusting the installation position of the side wall segment prefabricated block (21) to meet the requirements includes: Preliminary installation: a lifting device (7) is arranged according to the installation position of the side wall segment prefabricated block (21), the lifting device (7) comprising a bracket (71), a vertical adjustment device (72), a horizontal adjustment device (73) and a lifting device (74), the horizontal adjustment device (73) is installed on the bracket (71), the vertical adjustment device (72) is installed on the horizontal adjustment device (73), and the lifting device (74) is installed on the vertical adjustment device (72). During installation, the lifting device (74) is used to preliminarily install the side wall segment prefabricated block (21) at the installation position in the continuous wall installation groove (4) through a lifting rope; Precise position adjustment: a plurality of pushing mechanisms (8) are respectively arranged on both sides of the two ends of the side wall section prefabricated block (21) along the height direction of the continuous wall installation groove (4), and a plurality of distance measuring devices (9) are arranged on one side of the two ends of the side wall section prefabricated block (21) along the height direction of the continuous wall installation groove (4). During precise adjustment, the horizontal position between the side wall section prefabricated block (21) and the previous side wall section prefabricated block (21) is precisely adjusted by the horizontal adjustment device (73) to meet the requirements, and the side wall section prefabricated block (21) is precisely adjusted by the vertical adjustment device (72). The elevation of the prefabricated block (21) is adjusted to meet the requirements, and the distance between the different height positions at the two ends of the side wall section prefabricated block (21) and the groove wall of the continuous wall installation groove (4) is measured by the distance measuring device (9). Then, according to the distance data of the different height positions at the two ends of the side wall section prefabricated block (21) and the groove wall of the continuous wall installation groove (4) measured by the distance measuring device (9), the distance between the different height positions at the two ends of the side wall section prefabricated block (21) and the groove wall of the continuous wall installation groove (4) is adjusted by the pushing mechanism (8), so that the plane positioning and verticality of the side wall section prefabricated block (21) meet the requirements.

5. The method for constructing an assembled underground structure by digging and covering in reverse according to claim 4, characterized in that: The vertical adjustment device (72) and the horizontal adjustment device (73) are both electric screw slides.

6. The method for constructing an assembled underground structure by cover-excavation and reverse construction as claimed in claim 4, characterized in that: The prefabricated middle longitudinal beam (26) and the prefabricated middle plate (25) are hoisted and installed by means of a hoisting rail arranged on the prefabricated top plate (24); the bottom plate prefabricated steel cage (28) and the bottom longitudinal beam prefabricated steel cage (27) are hoisted and installed by means of a hoisting rail arranged on the prefabricated middle plate (25).

7. The assembled underground structure is characterized by: The prefabricated underground structure is constructed using the prefabricated underground structure cover-excavation reverse construction method described in any one of claims 1 to 6 above.

Images