CN109183807B - Movable steel support and construction method thereof - Google Patents
Movable steel support and construction method thereof Download PDFInfo
- Publication number
- CN109183807B CN109183807B CN201811085939.7A CN201811085939A CN109183807B CN 109183807 B CN109183807 B CN 109183807B CN 201811085939 A CN201811085939 A CN 201811085939A CN 109183807 B CN109183807 B CN 109183807B
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- guide rail
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 273
- 239000010959 steel Substances 0.000 title claims abstract description 273
- 238000010276 construction Methods 0.000 title claims abstract description 72
- 230000009471 action Effects 0.000 claims abstract description 4
- 238000009434 installation Methods 0.000 claims description 20
- 238000009412 basement excavation Methods 0.000 claims description 19
- 238000000034 method Methods 0.000 claims description 15
- 238000003825 pressing Methods 0.000 description 14
- 230000008569 process Effects 0.000 description 9
- 230000008901 benefit Effects 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000012141 concentrate Substances 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 239000003351 stiffener Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D17/00—Excavations; Bordering of excavations; Making embankments
- E02D17/02—Foundation pits
- E02D17/04—Bordering surfacing or stiffening the sides of foundation pits
Abstract
The invention discloses a movable steel support, which is used for supporting a foundation pit, wherein a supporting structure is arranged at the edge of the foundation pit, a plurality of guide rails and N layers of supporting parts which are arranged up and down are arranged in the foundation pit, N is more than or equal to 2, and each layer of supporting part comprises a steel purlin and a steel support connected to the steel purlin; the guide rails are fixed on the inner side of the supporting structure along the vertical direction, the steel purlin is fixedly provided with a guide part, the guide part is provided with a locking piece, and the locking piece can fix the guide part on the guide rails; when no prestressing force exists, the supporting part can move up and down along the guide rail under the action of external force. The application also discloses a construction method of the movable steel support. Due to the arrangement of the guide rail, the entire support part is held on the guide rail by means of the locking element, which can be separated from the guide rail, and after the locking element is separated from the guide rail, the support parts can be moved up and down. The supporting part is not required to be decomposed, so that a large amount of time can be saved, and the construction efficiency of the underground main body structure is improved.
Description
Technical Field
The invention relates to a supporting structure and a construction method in the process of excavating an underground foundation pit, in particular to a movable steel support and a construction method thereof.
Background
In order to ensure the safety of excavation of a foundation pit and construction of a main underground structure, particularly the construction of a deep foundation pit, a supporting structure and a plurality of supporting structures are generally required to be arranged in the foundation pit so as to ensure the construction safety. The steel support is to use steel such as steel pipes, H-shaped steel, angle steel and the like as a supporting structure so as to enhance the stability of engineering structures, and the steel pipes and the H-shaped steel are used for many purposes in engineering. The steel support is fast in erection and dismantling, the lower earthwork can be directly excavated without waiting for strength after the erection is finished, and the support material can be recycled, so that the method has the remarkable advantages of saving engineering cost and accelerating construction period. The steel support is widely applied to long and narrow foundation pits such as subways and comprehensive pipe racks. The deep foundation pit engineering generally adopts a plurality of supports, the first support is convenient to install and dismantle, the second support and the steel support below the second support are more troublesome to install and dismantle due to the influence of the supports, and therefore the excavation progress of the foundation pit and the construction efficiency of the underground main body structure are reduced.
Disclosure of Invention
In order to solve the problems, the invention firstly provides a movable steel support, which has the advantages of easy positioning and shorter operation flow, and the specific technical scheme is as follows:
the movable steel support is used for supporting a foundation pit, a supporting structure is arranged at the edge of the foundation pit, a plurality of guide rails and N layers of supporting parts which are arranged up and down are arranged in the foundation pit, N is more than or equal to 2, and each layer of supporting part comprises a steel enclosing purlin and a steel support connected to the steel enclosing purlin; the guide rails are fixed on the inner side of the supporting structure along the vertical direction, the steel purlin is fixedly provided with a guide part, the guide part is provided with a locking piece, and the locking piece can fix the guide part on the guide rails;
after prestressing the steel support, the steel support tightly supports the connected steel purlin against the supporting structure; when no prestress exists, the supporting part can move up and down along the guide rail under the action of external force;
when the supporting part moves up and down along the guide rail, the locking piece is in a state of being separated from the guide rail.
In this application, a guide rail is provided, on which the entire support is held by means of a locking element which can be separated from the guide rail, and after separation of the locking element from the guide rail, the support can be moved up and down. Therefore, before large-scale excavation of the foundation pit, the surface soil of the foundation pit is excavated, all the supporting parts are locked on the guide rail, and then the supporting parts are gradually lowered to the set positions along the guide rail along with the excavation of the foundation pit. Because each supporting part is assembled in advance to form a whole, in the process of excavating the foundation pit, only the supporting part is required to move downwards along the guide rail, so that the time for assembling the supporting part in the foundation pit is saved, and the construction progress of the foundation pit can be effectively improved. In the construction process of the underground main body structure, all the supporting parts can be moved upwards integrally without decomposing the supporting parts, so that a large amount of time can be saved, the construction efficiency of the underground main body structure is improved, and all the supporting parts are removed once in the final stage of construction.
Specifically, a connecting part is formed at the top of the guide rail, the connecting part of the guide rail is fixedly connected to the supporting structure, and the lower end surface of the guide rail extends downwards to the lower part of the bottom surface of the foundation pit; a through groove is formed between the guide rail and the supporting structure in the space between the connecting part and the bottom surface of the foundation pit; and a guide hole is formed in the steel purlin along the vertical direction, and the steel purlin is sleeved on the guide rail through the guide hole.
Preferably, the distance between the lower end face of the guide rail and the bottom face of the foundation pit is more than or equal to 0.5 meter.
After the through groove is formed, the steel purlin is sleeved on the guide rail, and a groove for clamping the guide rail is not required to be formed in the steel purlin, so that the appearance structure of the steel purlin is maintained to the greatest extent, when the prestress is applied to the steel support, the steel purlin can be tightly abutted against the supporting structure, and the supporting structure is ensured to be capable of being uniformly supported by the supporting force of the steel purlin.
Further, the guide rail is provided with at least two protruding strips extending in the vertical direction, and the locking piece is locked on the protruding strips.
After the raised strips are arranged along the vertical direction, the raised strips not only can be used as the acting points of the locking piece, but also have a certain guiding function, and the supporting part can be more stable when moving up and down.
In particular, the rail has an H-shaped cross section with a web and flanges disposed on opposite sides of the web, the flanges being perpendicular to the web; the flange is formed into the convex strip;
the guide part is provided with a guide body arranged at the edge of a guide hole of the steel purlin, a guide groove is arranged on the guide body, and at least one flange of the guide rail extends into the guide groove; the guide body is provided with a threaded through hole communicated with the guide groove, a fixing bolt is screwed in the threaded through hole, and the fixing bolt fixes the flange extending into the guide groove, so that the guide part is fixed on the guide rail; the fixing bolt is formed as the above-mentioned locking member.
The H-shaped section can enable the guide rail to be provided with four raised strips, and the H-shaped section has higher bending resistance and is particularly suitable for being used as the guide rail in a deep foundation pit. The guide groove is matched with the flange, so that the guide groove can be used as a mounting part of the locking piece, and a guide effect can be provided for movement of the guide rail.
In an embodiment, the guiding part comprises a guiding cylinder fixed on the steel purlin, the guiding cylinder extends along the vertical direction, the guiding cylinder is sleeved on the guide rail, at least two opposite sides of the side wall of the guiding cylinder are provided with through hole-shaped threaded locking holes, locking bolts are screwed in the threaded locking holes, and the locking bolts fix the guiding part on the guide rail; the lock bolt is formed as the above-described lock member. The guide rail with more structures can be practically used by adopting the guide cylinder, and the supporting part can be locked on the guide rail by utilizing the locking bolt arranged on the guide cylinder.
Preferably, the steel purlin is made of H-shaped steel, and a web plate of the H-shaped steel is horizontally arranged; the steel support is characterized in that two ends of the steel support are propped against the inner side surface of the steel purlin, a propping plate is arranged between the end surface of the steel support and the inner side surface of the steel purlin, the propping plate comprises a main body plate and a hook portion formed on the main body plate, and the propping plate is hung on the steel purlin through the hook portion. According to different geological conditions and specific materials, the steel purlin can be made of H-shaped steel, and specifically can be made of a single H-shaped steel or two H-shaped steel in double splicing mode.
After setting up the clamp plate that supports between steel support and steel and enclosing the purlin, the steel support is through supporting the clamp plate and connecting on steel encloses the purlin, in actual work progress, the steel support or the installation that steel encloses the purlin always have certain error, when directly setting up the mounting hole on steel encloses the purlin, can lead to steel support and steel to enclose the angle between the purlin and the angle of setting for and have certain error, this error can influence the prestressing force application to steel support. After the pressing plate is arranged, the pressing plate is used as an installation transition piece between the steel support and the steel purlin, the pressing plate is hung on the steel purlin, the steel support can be virtually hung on the pressing plate by bolts, namely, the bolts are not fastened, the steel support is only loosely connected to the pressing plate, the application of prestress to the steel support is not influenced, after the application of prestress is completed, the corresponding bolts are fastened, and the connection between the steel support and the steel purlin is completed. The position of the steel support can be freely adjusted by adopting the pressing plate, and the installation accuracy of the steel support can be improved.
Further, a column is arranged in the foundation pit, at least one steel support is provided with a guide hole, and the steel support is sleeved on the column through the guide hole. After the steel support is sleeved on the upright post, the upright post can be used as a guide rod, and the detachable bracket can be arranged on the upright post and used for supporting the steel support.
Another object of the present application is to provide a construction method of each of the above-mentioned movable steel support technical solutions, which specifically includes the following steps:
(1) Constructing a supporting structure along the periphery of a foundation pit to be excavated, and sinking a guide rail on the inner side of the foundation pit supporting structure;
(2) Excavating earthwork in the foundation pit area until the installation height of the first layer supporting part, suspending the excavation of the earthwork, installing all steel purlins and corresponding steel supports on the inner side of the supporting structure according to the arrangement sequence of the supporting parts, locking the locking piece on the guide rail, and then applying prestress to the steel supports of the first layer supporting part to enable the steel purlins of the first layer supporting part to be abutted against the inner side surface of the supporting structure, so as to finish the construction of the first layer supporting part;
(3) Continuing to excavate earthwork until the installation height of the second layer supporting part, suspending the excavation of the earthwork again, loosening the locking pieces on the supporting parts except the first layer supporting part, enabling all the supporting parts except the first layer supporting part to descend along the guide rail, enabling the second layer supporting part to descend to the set installation height, locking the locking pieces on all the supporting parts except the first layer supporting part onto the guide rail, applying prestress to the steel support of the second layer supporting part, enabling the steel purlin of the second supporting part to abut against the inner side surface of the supporting structure, and completing the construction of the second layer supporting part;
(4) When the supporting parts exceed two layers, completing the installation of the rest supporting parts and the excavation of earthwork according to the step (3);
(5) After the excavation of the foundation pit is completed, the construction of the underground main body structure is carried out.
The construction method fully embodies the advantage of adopting the movable steel support as a support system in the foundation pit construction process. In the construction process of the foundation pit, the supporting structure and the guide rail of the foundation pit are firstly constructed before the foundation pit is excavated, so that the foundation pit is excavated and the supporting parts are installed, before the supporting parts are installed, shallow excavation is firstly carried out on the foundation pit, so that the supporting parts are installed, as the shallow excavation of the foundation pit is only carried out, and as the assembly of all the supporting parts is completed at one time, the supporting parts are erected on the guide rail, the installation can be carried out from the supporting part at the lowest layer, and as the excavation depth of the foundation pit is shallower, the operation of various mechanical operations is more convenient, the assembly and erection of the supporting parts can be completed relatively quickly, and the integral time of the construction of the foundation pit is reduced.
After the excavation of the foundation pit is completed, a construction stage of the underground main body structure is entered, at which stage the supporting portion is moved up successively along with the progress of the construction of the underground main body structure and finally is intensively disassembled, in the application, the construction of the underground main body structure is performed from bottom to top, and the conditions of having two layers of supporting portions and exceeding the multiple layers of supporting portions are described respectively according to the different layers of the supporting portions.
When n=2, i.e. the number of support portions is two, the support portions are removed in sequence according to the following steps:
(6A) When the underground main body structure is constructed to the dismantling working condition of the second layer supporting part, suspending the construction of the underground main body structure, and unloading the prestress of the steel support of the second layer supporting part; loosening the locking piece on the second layer supporting part, then moving the steel purlin and the steel support of the second layer supporting part upwards to the lower side of the first layer supporting part, and locking the locking piece of the second layer supporting part to the guide rail;
(6B) Continuing to construct the underground main body structure, suspending the construction of the underground main body structure again until the dismantling working condition of the first layer of supporting part is met, unloading the prestress of the steel support of the first layer of supporting part, loosening the locking piece on the first layer of supporting part, and dismantling the steel support and the steel enclosing purlin of the first layer of supporting part; loosening the locking piece on the second layer supporting part, and dismantling the steel support and the steel enclosing purlin of the second layer supporting part;
when N is more than 2, the supporting parts are removed in sequence according to the following steps:
(7A) When the underground main body structure is constructed to meet the dismantling working condition of the N-th layer supporting part, suspending the construction of the underground main body structure, unloading the prestress of the steel support of the N-th layer supporting part, loosening the locking piece on the N-th layer supporting part, then moving the steel enclosing purlin and the steel support of the N-th layer supporting part upwards to the lower side of the N-1-th layer supporting part, and locking the locking piece of the N-th layer supporting part on the guide rail;
(7B) Continuing to construct the underground main body structure, suspending the construction of the underground main body structure again until the dismantling working condition of the N-1 layer supporting part is met, unloading the prestress of the steel support of the N-1 layer supporting part, loosening the locking pieces on the N layer supporting part and the N-1 layer supporting part, moving the steel purlin and the steel support of the N layer supporting part and the N-1 layer supporting part upwards to the lower side of the N-2 layer supporting part, and locking the locking pieces of the N layer supporting part and the N-1 layer supporting part to the guide rail;
(8B) And (3) continuing to construct the underground main body structure and the movement of the steel support according to the step (7B), until the underground main body structure is constructed until the dismantling working condition of the first layer of supporting parts is met, dismantling the steel purlin and the steel support of the first layer of supporting parts in sequence, and dismantling the steel support and the steel purlin of each layer of supporting parts in sequence.
In the process of underground main body structure construction, along with the continuous rising of underground main body structure construction height, the prestressing force of steel support is removed successively, then shift up the supporting part, in order to enlarge the construction area, keep the supporting part in the incomplete construction area in the effective supporting state to the foundation ditch simultaneously, when the underground main body structure construction reaches the first layer when the work condition is demolishd to the support of support, demolish each supporting part concentrate, because demolish each supporting part concentrate, each dismounting device is after accomplishing once location, can accomplish the work in the roughly same region of all supporting parts, the efficiency that the dismounting device needs many times location to lead to when having avoided dismantling the support many times. By adopting the method, the efficiency of each supporting part in installation can be improved, and the efficiency in disassembly can also be improved.
Drawings
FIG. 1 is a schematic view of a portion of an embodiment of a moveable steel support of the present invention.
Fig. 2 is an enlarged view of a portion a in fig. 1.
Fig. 3 is a schematic structural view of the guide frame.
Fig. 4 is a schematic structural view of the pressing plate.
Fig. 5 is a schematic view of the first layer support after the installation of the first layer support is completed and the second layer support and the third layer support are locked on the track.
Fig. 6 is a schematic view of the second layer support after the second layer support is mounted and the third layer support is locked to the rail.
Fig. 7 is a schematic view after the completion of the installation of the third layer supporting portion.
Fig. 8 is a schematic view after excavation of the foundation pit is completed.
Fig. 9 is a schematic view after finishing the cushion and the floor construction.
FIG. 10 is a schematic view of a portion of the subsurface body structure below the third layer of support.
Fig. 11 is a schematic view of the steel support with the third layer of support removed.
Fig. 12 is a schematic view of the steel support with the second layer support removed.
Fig. 13 is a schematic view of an underground utility structure being constructed adjacent a first floor support.
Fig. 14 is a schematic view of the completed subsurface body structure.
Detailed Description
In the present application, the direction toward the inside of the foundation pit is referred to as the inside, and the direction opposite to the inside is referred to as the outside. In the drawings, reference numeral 100 denotes the ground.
The movable steel support is first described below.
Referring to fig. 1 and 2, a movable steel support is used for supporting a foundation pit, a supporting structure 10 is arranged at the edge of the foundation pit, the supporting structure 10 is formed by mutually meshed combined steel sheet piles, each combined steel sheet pile comprises a U-shaped steel sheet pile 11 and an H-shaped steel pile 13 propped against the outer side of the U-shaped steel sheet pile 11, two channel steel 12 with opposite notches are welded on the outer side of a web plate of the U-shaped steel sheet pile 11, one side flange of the H-shaped steel pile 13 is clamped in a groove of the channel steel 12, and the H-shaped steel pile 13 and the U-shaped steel sheet pile 11 are integrally formed.
A plurality of guide rails 20 and three layers of supporting parts are disposed up and down in the foundation pit, and two layers of supporting parts near the upper side are shown in fig. 1, and please refer to fig. 8, in which the three layers of supporting parts are respectively referred to as a first layer of supporting part 30, a second layer of supporting part 60 and a third layer of supporting part 70 from top to bottom for convenience of description.
The first layer of bracing 30 includes a steel purlin 31 and steel bracing 32 attached to the inner side of the steel purlin. The steel purlin 31 is made of a first H-section steel, and a first web 313 of the first H-section steel is horizontally arranged. The guide rail 20 is fixed to the inner side of the supporting structure 10 in the vertical direction, the cross section of the guide rail 20 is H-shaped, the guide rail 20 has a second web 24 and second flanges 25 provided on opposite sides of the second web 24, and the second flanges 25 are perpendicular to the second web 24.
In particular, in this embodiment, the steel purlin is made of a single H-section steel, and it will be appreciated that in other embodiments, the steel purlin may also be made of double-spliced H-section steel. The steel support is made of H-shaped steel in particular, and in other embodiments, the steel support can also be made of steel tubes.
In particular, in this embodiment, the guide rail 20 is made of H-steel. It will be appreciated that in other embodiments, the guide rail may also be formed from steel plates spliced together.
In the present embodiment, the connecting bolt 22 is screwed into the bolt through hole on the second flange of the guide rail 20 facing outward, and the end of the screw of the connecting bolt is abutted against the inner side surface of the U-shaped steel sheet pile. It will be appreciated that in other embodiments, a spacer of set thickness may be provided between the rail 20 and the sheet pile 11, and a threaded hole provided in the sheet pile, and then a connecting bolt may be threaded through the second flange and then threaded into the threaded hole to secure the rail 20 to the sheet pile.
The threaded holes can be formed by forming threaded through holes in the U-shaped steel sheet piles or welding nuts or internally threaded sleeves on the steel sheet piles.
The guide rail 20 is arranged on the web plate of the U-shaped steel sheet pile facing the inner side direction of the foundation pit, and one side flange of the guide rail 20 is parallel to the web plate of the U-shaped steel sheet pile. The top of the guide rail 20 is provided with a connecting part 21, the connecting part 21 is fixedly connected to the web plate of the U-shaped steel sheet pile through a connecting bolt 22, and the lower end surface of the guide rail 20 extends downwards to the lower part of the bottom surface of the foundation pit; referring to fig. 8, a through groove 26 is formed between the guide rail 20 and the support structure 10 in the space between the connecting portion 21 and the bottom surface 80 of the foundation pit. A guide hole 311 is provided in the steel purlin 31 in the vertical direction, and the steel purlin 31 is sleeved on the guide rail 20 through the guide hole 311.
In this embodiment, the guide hole 311 is formed on the web 313 of the first H-shaped steel, and the inner flange 312 and the outer flange 314 of the first H-shaped steel are respectively located at the inner side and the outer side of the guide rail 20, that is, the inner flange 312 passes through the through groove 26, so that the inner flange 312 maintains integrity, so as to ensure the overall strength of the steel purlin, and the deformation of the steel purlin can be reduced to the greatest extent in the process of applying the prestress to the steel support 32 as described below.
A guide part is fixedly arranged on the steel purlin 31, and in this embodiment, the guide part includes guide frames 40 respectively arranged on the upper side and the lower side of the steel purlin 31. Referring to fig. 3, the guide frame 40 includes a bottom plate 41, a guide hole 48 is formed in the bottom plate 41 for a guide rail to pass through, a guide body 42 is respectively disposed on two opposite sides of the guide hole 48, a guide slot 43 is formed in the guide body 42, openings of the guide slots 43 of the two guide bodies are disposed oppositely, a first threaded through hole 44 is formed in a slot wall on one side of the guide slot, and a second threaded through hole 45 is formed in a slot wall on the other side of the guide slot. A first fixing bolt 47 is screwed into the first screw through hole 44, a second fixing bolt 49 is screwed into the second screw through hole 45, and a reinforcing plate 46 is provided between the top of the guide body 42 and the bottom plate 41.
The bottom plate 41 of the guide frame 40 is welded to the two flanges of the steel purlin 31, and the guide rail holes 48 are sleeved on the guide rail 20. The two sides of the second flange 25 facing outward of the guide rail 20 extend into one guide groove 43 respectively, and the first fixing bolt 47 and the second fixing bolt 49 are screwed to fix the second flange 25 facing outward in the guide groove 43, so that the steel purlin 31 is fixed on the guide rail 20.
It will be appreciated that in other embodiments the width of the guide channel may be set wider so that both second flanges of the rail 20 may extend into the guide channel at the same time. Or 4 guide grooves which are opposite to each other are arranged, so that the two second flanges respectively extend into the two opposite guide grooves. Of course, only one guide groove may be provided.
In this embodiment the guide frame has a stiffening plate 46, it being understood that in other embodiments the stiffening plate 46 may be eliminated when there is sufficient strength of connection between the guide body and the base plate. It will be appreciated that in other embodiments, the stiffener 46 and bottom plate 41 may be eliminated and the guide 42 welded directly to the steel purlin 31; or only one guide body, i.e. only one guide groove, is provided.
That is, the guide part has a guide body provided at the edge of the guide hole of the steel purlin, a guide groove is provided on the guide body, and at least one flange of the guide rail extends into the guide groove; the guide body is provided with a threaded through hole communicated with the guide groove, a fixing bolt is screwed in the threaded through hole, and the fixing bolt fixes the flange extending into the guide groove, so that the guide part is fixed on the guide rail. The first fixing bolt and the second fixing bolt are collectively referred to herein as fixing bolts, i.e., locking members.
In this embodiment, the guide rail is made of H-shaped steel, the H-shaped steel has two flanges parallel to each other, any side of the flanges can be regarded as a protruding strip extending along the vertical direction, and the protruding strip extends into the guide groove.
The second support 60 and the third support 70 have the same structure as the first support 30.
After prestressing the steel support, it tightly butts the connected steel purlin 31 against the supporting structure 10; when no prestress exists, the supporting part can move up and down along the guide rail under the action of external force; when the supporting part moves up and down along the guide rail, the locking piece is in a state of being separated from the guide rail.
In this embodiment, the distance F between the lower end surface of the guide rail and the bottom surface of the foundation pit is 0.5 meters. The lower end surface of the guide rail is extended below the bottom surface of the foundation pit in order to form a relatively fixed state of the lower end of the guide rail, it being understood that in other embodiments the distance F may be greater than 0.5 meters.
For easy loading and unloading of the steel support, two ends of the steel support 32 are abutted against the inner side surface of the steel purlin 31, an abutment plate 50 is disposed between the end surface of the steel support 32 and the inner side surface of the steel purlin 31, referring to fig. 4, the abutment plate 50 includes a main body plate 51, two opposite sides of the main body plate 51 are respectively formed with a hooking portion 52, a groove 53 is disposed between the hooking portion 52 and the main body plate 51, a first fixing hole 54 is formed in the main body plate 51, and a second fixing hole 55 is formed in the hooking portion.
Wherein the second fixing hole 55 is used for fixing the pressing plate 50 on the inner flange 312 of the first H-section steel. When the pressing plate 50 is installed, two sides of the inner flange 312 of the first H-shaped steel are sleeved into the two hook grooves 53 of the pressing plate 50, then the pressing plate is moved along the length direction of the first H-shaped steel until reaching the set top position, and then the pressing plate 50 is fixed on the steel enclosing purlin 31 by the pressing bolts 56.
The first fixing hole 54 is used to connect the steel support 32. End plates 33 are welded at two ends of the steel support 32, and after the steel support is positioned and pre-stressed, support bolts 34 are screwed into first fixing holes 54 of the pressing plates 50 after passing through the end plates 33, so that the steel support 32 is connected to the steel purlin 31.
In the present embodiment, a column 300 is provided in the foundation pit, a guide hole 38 is provided in the steel support 32, and the steel support 32 is fitted over the column 300 via the guide hole 38. When the supporting part moves up and down, the column 300 may play a guiding role. In this embodiment, all of the posts pass through the steel support. It will be appreciated that in other embodiments, only a portion of the uprights may pass through the steel support, or only one upright may pass through the steel support. That is, at least one steel support is provided with a guide hole, and the steel support is sleeved on the upright post through the guide hole.
In this embodiment, the steel purlin is fixed on the guide rail by adopting a structure that the raised strips and the guide grooves are mutually matched, it can be appreciated that in other embodiments, the guide part can also be provided with a structure that is provided with a guide cylinder, the guide cylinder is fixed on the steel purlin and extends along the vertical direction, the guide cylinder is sleeved on the guide rail, then two opposite sides of the side wall of the guide cylinder are provided with through hole-shaped thread locking holes, then the locking bolt is screwed in the thread locking through holes, and the guide part is fixed on the guide rail by the locking bolt; the locking bolt is formed as a locking member.
When the guide cylinder is adopted, materials with various structural forms can be adopted to manufacture the guide rail, for example, round steel pipes, square pipes and cement piles or wood piles can be used as the guide rail.
In this embodiment, the supporting structure adopts a composite steel sheet pile, and it will be understood that in other embodiments, the supporting structure may also be formed by a pile body such as a cast-in-place pile plus cement-soil mixing pile waterproof curtain, an SMW construction method pile, an underground diaphragm wall or other forms of steel sheet pile, and a composite steel sheet pile or a composite steel pipe pile.
The following describes a construction method of the movable steel support, specifically taking the construction of the movable steel support as an example, the construction method specifically includes the following steps:
(1) Referring to fig. 5, a supporting structure 10 is constructed along the circumference of a foundation pit to be excavated, and a guide rail 20 is sunk inside the foundation pit supporting structure 10.
(2) With continued reference to fig. 5, earth is excavated in the pit area until the installation height of the first layer of supporting parts 30, the excavation of the earth is suspended, all the steel purlins and the corresponding steel supports are installed on the inner side of the supporting structure according to the arrangement sequence of the supporting parts, the locking piece is locked on the guide rail, and then the steel supports of the first layer of supporting parts are prestressed, so that the steel purlins of the first layer of supporting parts are abutted against the inner side surface of the supporting structure, and the construction of the first layer of supporting parts is completed.
After all the steel purlins are sleeved on the guide rail 20, referring to fig. 1, connecting bolts 22 are connected to the U-shaped steel sheet piles after passing through the guide rail 20 so as to fix the upper ends of the guide rail 20.
In the present embodiment, the first layer support 30 is located at the uppermost layer, and the second layer support 60 and the third layer support 70 are located in this order.
(3) Referring to fig. 6, excavating earth is continued until the installation height of the second layer supporting portion 60, excavating earth is paused again, locking pieces on the second layer supporting portion 60 and the third layer supporting portion 70 are loosened, the second layer supporting portion 60 and the third layer supporting portion 70 are lowered along the guide rail, the second layer supporting portion 60 is lowered to the set installation height, then the locking pieces on the second layer supporting portion 60 and the third layer supporting portion 70 are locked on the guide rail, prestress is applied to steel supports of the second layer supporting portion, and steel purlins of the second layer supporting portion are abutted against the inner side surfaces of the supporting structure, so that construction of the second layer supporting portion is completed.
That is, the locking pieces on the supporting parts except the first layer supporting part are released, all the supporting parts except the first layer supporting part are lowered along the guide rail, the second layer supporting part is lowered to the set installation height, then the locking pieces on all the supporting parts except the first layer supporting part are locked on the guide rail, the steel support of the second layer supporting part is prestressed, and the steel purlin of the second layer supporting part is abutted against the inner side surface of the supporting structure, so that the construction of the second layer supporting part is completed.
(4) Referring to fig. 7, the earthwork is excavated continuously until the construction elevation of the third layer supporting portion 70, then the earthwork is excavated again, the locking piece on the third layer supporting portion 70 is loosened, the third layer supporting portion 70 is lowered to the set height along the guide rail and locked on the guide rail, the steel support of the third layer supporting portion is applied with prestress, the steel purlin of the third layer supporting portion is abutted against the inner side surface of the supporting structure, and the construction of the third layer supporting portion is completed.
(5) Referring to fig. 8 and 9, excavation of earth in the foundation pit is continued and completed. And then paving a cushion layer 84 and a casting bottom plate 82 on the bottom surface 80 of the foundation pit, and performing construction of the underground main body structure.
When the construction of the main body structure is carried out, the construction is carried out from bottom to top, and in the construction process, the supporting part is dismantled according to the following steps:
(7A) Referring to fig. 10 and 11, when the underground main structure 90 is constructed to satisfy the dismantling operation of the third layer supporting portion 70, the construction of the underground main structure 90 is suspended, the prestress of the steel support of the third layer supporting portion 70 is removed, the locking piece on the third layer supporting portion is released, then the steel purlin and the steel support of the third layer supporting portion are moved upward to the lower side of the second layer supporting portion, and then the locking piece of the third layer supporting portion is locked to the guide rail.
Then, continuing to construct the main structure upward, fig. 11 shows that after the steel purlin of the third layer supporting portion is moved upward, the construction of the second layer intermediate plate 92 is completed, and the second layer ring beam 91 is provided at the outer periphery of the intermediate plate 92.
(7B) Referring to fig. 12 and 13, continuing to construct the underground main structure until the dismantling condition of the second-layer supporting portion 60 is satisfied, suspending the construction of the underground main structure again, and removing the prestress of the steel support of the second-layer supporting portion; releasing the locking pieces on the third layer supporting part and the second layer supporting part, moving the steel purlins and the steel supports of the third layer supporting part and the second layer supporting part upwards to the lower side of the first layer supporting part, and locking the locking pieces of the third layer supporting part and the second layer supporting part to the guide rail.
In fig. 13, the construction of the first-layer intermediate plate 94 has been completed, and the first-layer ring beam 93 is provided on the outer periphery of the intermediate plate 94.
(8B) Referring to fig. 14, the movement of the underground utility structure and the steel support is continued according to step (7B), the removal of the first layer support portion 30 is completed, and the removal of the second support portion 60 and the third support portion 70 is completed.
In fig. 14, it is shown that the removal of all the supporting parts has been completed, and the construction of the underground main structure provided with the top plate 96 and the top ring beam 95 provided around the top plate 96.
In the present embodiment, the construction of the movable steel support provided with the three-layered support portion is described, and it is understood that the above-described step (8B) is omitted when the support portion is provided with only two layers.
Alternatively, when the movable steel support is provided with more than three layers of support portions, it is only necessary to repeat the above-described step (7B).
In this embodiment, referring to fig. 1 and 2, brackets 322 are disposed on both sides of the steel support in the horizontal direction, and when prestressing force is applied to the steel support 32, a jack 400 is disposed between the steel purlin 31 and the brackets 322, and in fig. 2, a jack is exemplarily shown on one side of the steel support, and when prestressing force is actually applied, the jack needs to be installed on both sides of the steel support at the same time. In the process of applying prestress to the steel support, the backing plate 35 is tightly plugged into a gap between the steel support and the steel purlin, and after the prestress is applied to a set value, the support bolts 34 are screwed, so that the steel support is fixedly connected to the steel purlin. It will be appreciated that the prestressing force may be applied in other ways known in the art, for example by arranging the jack between the end of the steel support and the steel purlin, and displacing the jack with a displacement device after the prestressing force has been applied.
In order to facilitate lifting of the support portion, lifting lugs 321 are provided on the upper side of the steel support, lifting of the support portion is performed by means of a crane or other lifting mechanism at the edge of the foundation pit, and auxiliary installation is performed. Of course, lifting lugs can be arranged on the steel purlin according to specific construction requirements.
Claims (9)
1. A construction method of a movable steel support is characterized in that,
the movable steel support is used for supporting a foundation pit, a supporting structure is arranged at the edge of the foundation pit, a plurality of guide rails and N layers of supporting parts which are arranged up and down are arranged in the foundation pit, N is more than or equal to 2, and each layer of supporting part comprises a steel enclosing purlin and a steel support connected to the steel enclosing purlin; the guide rails are fixed on the inner side of the supporting structure along the vertical direction, the steel purlin is fixedly provided with a guide part, the guide part is provided with a locking piece, and the locking piece can fix the guide part on the guide rails;
after prestressing the steel support, the steel support tightly supports the connected steel purlin against the supporting structure; when no prestress exists, the supporting part can move up and down along the guide rail under the action of external force;
when the supporting part moves up and down along the guide rail, the locking piece is in a state of being separated from the guide rail;
the construction method comprises the following steps:
(1) Constructing a supporting structure along the periphery of a foundation pit to be excavated, and sinking a guide rail on the inner side of the foundation pit supporting structure;
(2) Excavating earthwork in the foundation pit area until the installation height of the first layer supporting part, suspending the excavation of the earthwork, installing all steel purlins and corresponding steel supports on the inner side of the supporting structure according to the arrangement sequence of the supporting parts, locking the locking piece on the guide rail, and then applying prestress to the steel supports of the first layer supporting part to enable the steel purlins of the first layer supporting part to be abutted against the inner side surface of the supporting structure, so as to finish the construction of the first layer supporting part;
(3) Continuing to excavate earthwork until the installation height of the second layer supporting part, suspending the excavation of the earthwork again, loosening the locking pieces on the supporting parts except the first layer supporting part, enabling all the supporting parts except the first layer supporting part to descend along the guide rail, enabling the second layer supporting part to descend to the set installation height, locking the locking pieces on all the supporting parts except the first layer supporting part onto the guide rail, applying prestress to the steel support of the second layer supporting part, enabling the steel purlin of the second supporting part to abut against the inner side surface of the supporting structure, and completing the construction of the second layer supporting part;
(4) When the supporting parts exceed two layers, completing the installation of the rest supporting parts and the excavation of earthwork according to the step (3);
(5) After the excavation of the foundation pit is completed, the construction of the underground main body structure is carried out.
2. The method of construction according to claim 1, wherein the construction of the underground main structure is performed from bottom to top,
when n=2, the support portions are removed in sequence according to the following steps:
(6A) When the underground main body structure is constructed to the dismantling working condition of the second layer supporting part, suspending the construction of the underground main body structure, and unloading the prestress of the steel support of the second layer supporting part; loosening the locking piece on the second layer supporting part, then moving the steel purlin and the steel support of the second layer supporting part upwards to the lower side of the first layer supporting part, and locking the locking piece of the second layer supporting part to the guide rail;
(6B) Continuing to construct the underground main body structure, suspending the construction of the underground main body structure again until the dismantling working condition of the first layer of supporting part is met, unloading the prestress of the steel support of the first layer of supporting part, loosening the locking piece on the first layer of supporting part, and dismantling the steel support and the steel enclosing purlin of the first layer of supporting part; loosening the locking piece on the second layer supporting part, and dismantling the steel support and the steel enclosing purlin of the second layer supporting part;
when N is more than 2, the supporting parts are removed in sequence according to the following steps:
(7A) When the underground main body structure is constructed to meet the dismantling working condition of the N-th layer supporting part, suspending the construction of the underground main body structure, unloading the prestress of the steel support of the N-th layer supporting part, loosening the locking piece on the N-th layer supporting part, then moving the steel enclosing purlin and the steel support of the N-th layer supporting part upwards to the lower side of the N-1-th layer supporting part, and locking the locking piece of the N-th layer supporting part on the guide rail;
(7B) Continuing to construct the underground main body structure, suspending the construction of the underground main body structure again until the dismantling working condition of the N-1 layer supporting part is met, unloading the prestress of the steel support of the N-1 layer supporting part, loosening the locking pieces on the N layer supporting part and the N-1 layer supporting part, moving the steel purlin and the steel support of the N layer supporting part and the N-1 layer supporting part upwards to the lower side of the N-2 layer supporting part, and locking the locking pieces of the N layer supporting part and the N-1 layer supporting part to the guide rail;
(8B) And (3) continuing to construct the underground main body structure and the movement of the steel support according to the step (7B), until the underground main body structure is constructed until the dismantling working condition of the first layer of supporting parts is met, dismantling the steel purlin and the steel support of the first layer of supporting parts in sequence, and dismantling the steel support and the steel purlin of each layer of supporting parts in sequence.
3. The construction method according to claim 1, wherein a connecting portion is formed at the top of the guide rail, the connecting portion of the guide rail is fixedly connected to the supporting structure, and the lower end face of the guide rail extends downward below the bottom face of the foundation pit; a through groove is formed between the guide rail and the supporting structure in the space between the connecting part and the bottom surface of the foundation pit;
and a guide hole is formed in the steel purlin along the vertical direction, and the steel purlin is sleeved on the guide rail through the guide hole.
4. The method according to claim 3, wherein the distance between the lower end face of the guide rail and the bottom face of the foundation pit is not less than 0.5 m.
5. The construction method according to claim 3 or 4, wherein the guide rail has at least two protrusions extending in a vertical direction, and the locking member is locked to the protrusions.
6. The method of construction according to claim 5, wherein the rail has an H-shaped cross section and has a web and flanges disposed on opposite sides of the web, the flanges being perpendicular to the web; the flange is formed into the convex strip;
the guide part is provided with a guide body arranged at the edge of a guide hole of the steel purlin, a guide groove is arranged on the guide body, and at least one flange of the guide rail extends into the guide groove; the guide body is provided with a threaded through hole communicated with the guide groove, a fixing bolt is screwed in the threaded through hole, and the fixing bolt fixes the flange extending into the guide groove, so that the guide part is fixed on the guide rail; the fixing bolt is formed as the above-mentioned locking member.
7. The construction method according to claim 3 or 4, wherein the guide part comprises a guide cylinder fixed on the steel purlin, the guide cylinder extends in the vertical direction, the guide cylinder is sleeved on the guide rail, at least two opposite sides of the side wall of the guide cylinder are provided with through hole-shaped threaded locking holes, locking bolts are screwed in the threaded locking holes, and the locking bolts fix the guide part on the guide rail; the lock bolt is formed as the above-described lock member.
8. The construction method according to claim 1, wherein the steel purlin is made of H-steel, and a web of the H-steel is horizontally arranged;
the steel support is characterized in that two ends of the steel support are propped against the inner side surface of the steel purlin, a propping plate is arranged between the end surface of the steel support and the inner side surface of the steel purlin, the propping plate comprises a main body plate and a hook portion formed on the main body plate, and the propping plate is hung on the steel purlin through the hook portion.
9. The method according to claim 1, wherein a column is provided in the foundation pit, and at least one steel support is provided with a guide hole, and the steel support is sleeved on the column through the guide hole.
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| CN110714467B (en) * | 2019-10-29 | 2021-01-01 | 南京同力建设集团股份有限公司 | Deep foundation pit supporting system |
| CN110984170B (en) * | 2019-11-25 | 2021-07-16 | 上海水务建设工程有限公司 | Semi-automatic foundation pit steel support installation method and steel support installation auxiliary device |
| CN110952985B (en) * | 2019-11-28 | 2021-10-26 | 苏州中车建设工程有限公司 | Sliding type vertical shaft annular steel support assembly and construction method |
| CN112049112B (en) * | 2020-09-16 | 2021-09-21 | 南京深地智能建造技术研究院有限公司 | Operation platform for pile pulling, pile pulling device and pile pulling method |
| CN113202117A (en) * | 2021-05-07 | 2021-08-03 | 中交一公局集团有限公司 | Larsen steel sheet pile construction process |
| CN113235618B (en) * | 2021-06-01 | 2023-03-31 | 中国建筑第八工程局有限公司 | Support system in slip type foundation pit and construction method thereof |
| CN113756347B (en) * | 2021-10-09 | 2023-02-03 | 山东高速路桥集团股份有限公司 | Supporting bearing platform construction auxiliary equipment and construction method |
| CN114232637B (en) * | 2021-10-26 | 2023-10-03 | 江苏东合南岩土科技股份有限公司 | Connection structure of H-shaped steel connecting beam and H-shaped steel main support and construction method of horizontal support |
| CN114657999B (en) * | 2022-03-07 | 2023-04-25 | 中冶集团武汉勘察研究院有限公司 | Combined pile supporting structure for cylindrical foundation pit and construction method |
| CN115305919A (en) * | 2022-07-06 | 2022-11-08 | 中煤浙江基础建设有限公司 | Foundation pit excavation earthwork landslide prevention enclosure structure and construction method thereof |
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