Initiatively underpinning structure and support and change method of the entirety of the many pile foundations of a kind of bridge large-tonnage
Technical field
The present invention relates to Pile Underpinning Technology, relate in particular to initiatively underpinning structure and the support and change method of entirety of the many pile foundations of a kind of bridge large-tonnage.
Background technology
The Railway Transit Construction of China take subway as representative is just in the ascendant at present, and in subway construction process, its running tunnel and existing municipal bridge space crossed situation occur and happen occasionally.Following two kinds nothing but of the schemes that now adopted: 1) tear bridge open and rebuild, make the arrangement of pile foundation of new bridge avoid planning to build shield structure running tunnel; 2) underpin there are some space crossed bridge pile foundations.Tear bridge reconstruction model open and invest large and have a strong impact on surrounding environment, less employing at present, and pile foundation underpinning scheme is less to urban environmental impact, is more and more used widely.
Conventional bridge pile foundation underpins scheme both at home and abroad at present, says from form of structure the underpinning structure that generally all adopts shoulder pole apron piece; As shown in Figure 1a: the load of being born by underpinned pile 1 ', by one shoulder pole apron piece 3 ', passes to two new stakes 2 '.Say and can be divided into passive type (as shown in Figure 1 b) and active (as shown in Fig. 1 c) from joint structure: the former first completes the construction of two new stakes 2 ', apply again apron piece 3 ', complete the node construction at connecting the newly built structure to the pristine structure place simultaneously, then in the situation that former pile foundation 1 ' is still born load, blocked, completed stressed conversion; The latter first completes the construction of two new stakes 2 ', apply again apron piece 3 ', complete the node construction at connecting the newly built structure to the pristine structure place simultaneously, blocked after then former pile foundation 1 ' being offloaded to zero axle power by jack 4 ' and anchor ear 5 ', finally remove jack 4 ' and complete stressed conversion.
It is at present technical comparatively ripe that above-mentioned bridge pile foundation underpins scheme, but if desired many bridge pile foundations are carried out to structure while underpining simultaneously, and above-mentioned traditional scheme that underpins still has the following disadvantages.
1) tradition underpins the form of structure that scheme adopts two new stakes to add shoulder pole apron piece and carries out stressed conversion, required new stake quantity is 2 times by underpinned pile quantity, if desired many piles base is underpined simultaneously, be subject to steric requirements restriction usually cannot arrange the plan-position of new stake.
2) adopting tradition to underpin scheme underpins many piles base of bridge construction, if the upper load of respectively being born by underpinned pile differs greatly, complete after stressed conversion, respectively between underpinned pile, easily produced relative settlement, and then cause the adverse consequences such as bridge superstructure cracking.
3) tonnage of upper load that bridge pile foundation is born is normally larger, and tradition underpins and underpins joint structure (no matter passive type or active) in scheme, all adopt the mode of alligator and bar planting to transmit the shearing between new and old structure, its safety factor is less, is very disadvantageous to bridge construction durability.
Summary of the invention
One of the technical problem to be solved in the present invention, is to provide the initiatively underpinning structure of entirety of the many pile foundations of a kind of bridge large-tonnage, and the new stake number of its required laying is less, has avoided being subject to steric requirements to limit the difficulty that cannot lay out pile; Be conducive to adjust each by the relative settlement between underpinned pile, its stress performance and durability are comparatively reliable.
One of technical problem of the present invention is achieved in that the initiatively underpinning structure of entirety of the many pile foundations of a kind of bridge large-tonnage, and described entirety initiatively underpinning structure comprises: multiple longitudinal apron pieces, multiple horizontal apron piece and multiple after water steel bar concrete and underpin assembly;
Multiple horizontal apron pieces and multiple longitudinal apron piece are integral cast-in-situ, longitudinally reservedly on apron piece water node headspace after multiple; After described, water steel bar concrete and underpin assembly and be placed in after described and water in node headspace, water steel bar concrete after described and underpin assembly and comprise: muscle is undercuted in Punching Shear muscle and beams in anchor ear, at least four jack, the main muscle of pile body, spiral stirrup, beam; Described anchor ear be arranged at bridge by underpinned pile, described four jack are placed between longitudinal apron piece and anchor ear; The main muscle of described pile body is for connecting the main muscle of former pile body being truncated; Described spiral stirrup is wound on the main muscle of pile body of spreading; In described beam, Punching Shear muscle should overlap with the main muscle of the upside of longitudinal apron piece, for node Punching Shear; The muscle that undercuted in described beam should overlap with the main muscle of the downside of longitudinal apron piece, for the bending resistance of node body.
Two of the technical problem to be solved in the present invention, is to provide the initiatively support and change method of entirety of the many pile foundations of a kind of bridge large-tonnage, and the new stake number of its required laying is less, has avoided being subject to steric requirements to limit the difficulty that cannot lay out pile; Be conducive to adjust each by the relative settlement between underpinned pile, its stress performance and durability are comparatively reliable.
Two of technical problem of the present invention is achieved in that the initiatively support and change method of entirety of the many pile foundations of a kind of bridge large-tonnage, described method need provide initiatively underpinning structure of entirety, and this entirety initiatively underpinning structure comprises: multiple longitudinal apron pieces, multiple horizontal apron piece and multiple after water steel bar concrete and underpin assembly; After water steel bar concrete and underpin assembly and comprise: anchor ear and at least four jack; The method concrete steps are:
Step 1, under bridge, form a foundation ditch, on described foundation ditch, apply new stake, laterally apron piece and longitudinal apron piece, simultaneously reservedly in longitudinal apron piece water node space after multiple;
Step 2, on by underpinned pile, build described anchor ear, synchronous jack is placed between anchor ear and longitudinal apron piece, apply step by step top lift by anchor ear, will be offloaded to zero axle power by underpinned pile, then below anchor ear with longitudinally, below apron piece, block for twice by underpinned pile;
Step 3, longitudinal apron piece with by underpinned pile between, after applying, water steel bar concrete and underpin assembly, complete by the stressed conversion between underpinned pile and longitudinal apron piece;
Step 4, to each velamen underpinned pile, repeated execution of steps 2 and step 3, the entirety that finally completes all bridge pile foundations initiatively underpins.
Further, described step 3 is specially: after longitudinal apron piece, waters in node space, and the main muscle of former pile body that spreading is truncated, and be wound around a spiral stirrup on the main muscle of spreading pile body, after water Punching Shear muscle in a beam be set in node space, and with the main muscle overlap joint of upside of longitudinal apron piece; After water the muscle that undercuted in a beam be set in node space, and with the main muscle overlap joint of downside of longitudinal apron piece; Finally after water in node space and build slightly expanded concrete, after reaching preset strength, remove jack, complete stressed conversion.
Further, build anchor ear on by underpinned pile time, described anchor ear and by can be by the mode Transfer of Shear of alligator and bar planting between underpinned pile.
Tool of the present invention has the following advantages: 1) the new stake number of required laying is less, has avoided being subject to steric requirements to limit the difficulty that cannot lay out pile; 2) stressed transduction pathway is clear and definite, acts on the load being underpined in pile foundation and first passes to longitudinal apron piece, then pass to horizontal apron piece, is finally delivered in each new stake; 3) integral rigidity of the apron piece in length and breadth of monobloc cast is larger, is conducive to adjust each by the relative settlement between underpinned pile, avoids the adverse consequences such as bridge superstructure cracking; 4) for bearing the bridge pile foundation of large-tonnage load, that after employing, waters steel bar concrete underpins node Transfer of Shear, and than the Shear transfer mode of alligator and bar planting, its stress performance and durability are comparatively reliable.5) in whole pile foundation underpinning work progress without interrupting municipal traffic, very little to urban environmental impact, but should to limit the bridge floor of heavy vehicle current for safety plays mirror.
Accompanying drawing explanation
Fig. 1 a is the schematic diagram of the underpinning structure of existing employing shoulder pole apron piece.
Fig. 1 b is the schematic diagram of the passive type underpinning structure of existing employing joint structure.
Fig. 1 c is the schematic diagram of the passive type underpinning structure of existing employing joint structure.
Fig. 2 is the initiatively floor map of underpinning structure of the many pile foundation entirety of bridge large-tonnage of the present invention.
Fig. 3 is the initiatively elevational schematic view of underpinning structure of the many pile foundation entirety of bridge large-tonnage of the present invention.
Fig. 4 is the initiatively nodal plane detail drawings of underpinning structure of the many pile foundation entirety of bridge large-tonnage of the present invention.
Fig. 5 is the initiatively node facade detail drawings of underpinning structure of the many pile foundation entirety of bridge large-tonnage of the present invention.
The specific embodiment
Refer to shown in Fig. 2 to Fig. 5, the initiatively underpinning structure of entirety of the many pile foundations of a kind of bridge large-tonnage of the present invention, described entirety initiatively underpinning structure comprises: multiple horizontal apron pieces 1, multiple longitudinal apron piece 2 and multiple after water steel bar concrete and underpin assembly 3;
Multiple horizontal apron pieces 1 be integral cast-in-situ with multiple longitudinal apron pieces 2, longitudinally on apron piece 2, reserve after multiple and water node headspace 4; After described, water steel bar concrete and underpin assembly 3 and be placed in after described and water in node headspace 4, water steel bar concrete after described and underpin assembly 3 and comprise: muscle 36 is undercuted in Punching Shear muscle 35 and beam in anchor ear 31, at least four jack 32, the main muscle 33 of pile body, spiral stirrup 34, beam; Described anchor ear 31 be arranged at bridge by underpinned pile 5; Described two very heavy 32 overheads are between longitudinal apron piece 2 and anchor ear 31; The main muscle 33 of described pile body is for connecting the main muscle of former pile body being truncated; On the main muscle 33 of pile body that described pile body stirrup 34 is wound in spreading; In described beam, Punching Shear muscle 35 should overlap with the main muscle of the upside of longitudinal apron piece, for node Punching Shear; The muscle 36 that undercuted in described beam should overlap with the main muscle of the downside of longitudinal apron piece, for the bending resistance of node body.
Refer to shown in Fig. 2 to Fig. 5, initiatively support and change method of the entirety of the many pile foundations of a kind of bridge large-tonnage of the present invention, described method need provide initiatively underpinning structure of entirety, and this entirety initiatively underpinning structure comprises: multiple longitudinal apron pieces 2, multiple horizontal apron piece 1 and after water steel bar concrete and underpin assembly 3; After water steel bar concrete and underpin assembly 3 and comprise: muscle 36 is undercuted in Punching Shear muscle 35 and beam in anchor ear 31, at least four jack 32, the main muscle 33 of pile body, spiral stirrup 34, beam; The method is specially:
Step 1, under bridge, form a foundation ditch, on described foundation ditch, apply new stake 6, laterally apron piece 1 and longitudinal apron piece 2, simultaneously reservedly in longitudinal apron piece 2 water node space 4 after multiple.
Step 2, on by underpinned pile 5, build described anchor ear 31, described anchor ear 31 and by mode 7 Transfer of Shear by alligator and bar planting between underpinned pile 5, then synchronous jack 32 is placed between anchor ear 31 and longitudinal apron piece 1, apply step by step top lift by anchor ear 31, to be offloaded to zero axle power by underpinned pile 5, then below anchor ear 31 and below longitudinal apron piece 2, block for twice by underpinned pile 5.
Step 3, longitudinal apron piece 2 with by underpinned pile 5 between, after applying, water the node that underpins of steel bar concrete, complete by the stressed conversion between underpinned pile 5 and longitudinal apron piece 2; This step is specially: after longitudinal apron piece 2, water in node space 4, the main muscle 33 of colligation pile body also overlaps with the main muscle of former pile body, and on by the main muscle 33 of the pile body of spreading winding screw stirrup 34, after water interior Punching Shear muscle 35 in beam the main muscle overlap joint of upside with longitudinal apron piece of arranging of node space 4, after water the interior muscle 36 overlapping with the main muscle of downside of longitudinal apron piece of being undercuted in beam that arranges of node space 4, finally after water after-pouring slightly expanded concrete (not shown) on node space 4, after reaching preset strength, remove jack, complete stressed conversion.
Step 4, to each velamen underpinned pile, repeated execution of steps 2 and step 3, the entirety that finally completes all bridge pile foundations initiatively underpins.
Below in conjunction with a specific embodiment, the invention will be further described:
Certain subway sectional tunnel passes through certain river (the thing flow direction) along major urban arterial highway (south-north direction), occur space crossed with 6 pile bases of existing bridge, adopt support and change method of the present invention, these 6 bridge pile foundations are carried out to entirety and initiatively underpin, be now described in detail as follows.
1) apply cofferdam in some meters of positions of bridge location upstream and downstream, form foundation ditch to block river, for construction under bridge provides enough work planes.Should arrange water pipe communication upstream and downstream current simultaneously, and avoid river course congested.
2) in foundation ditch, apply 9 new stakes, the longitudinal apron piece of the 3 horizontal apron piece in road and 3 roads.New stake diameter can, with identical by underpinned pile, should pass through calculative determination but new stake stake is long, conventionally should be greater than former stake stake long.The height and the width of apron piece should be passed through calculative determination in length and breadth, should get large value, make it have enough rigidity, are conducive to control each by the relative settlement between underpinned pile.Longitudinally apron piece with by underpinned pile joint, after should reserving, water node space, should strengthen arrangement of reinforcement in the beam of reserving hole periphery simultaneously.
3) built anchor ear by underpinned pile top, between the two, by the mode Transfer of Shear of alligator and bar planting, anchor ear height and bar planting quantity should be passed through calculative determination, guarantee that its shear-carrying capacity is greater than construction period and acts on the top lift on this.
4) 4 hydraulic jack are placed between anchor ear and longitudinal apron piece, synchronously apply step by step top lift, make to be approached zero by underpinned pile axle power.Its top lift should pass through calculative determination, should consider the impact of superstructure, also needs to consider frictional force between stake soil, and therefore the required top lift that applies is generally greater than this original born load.
5) jacking locks jack cylinder after putting in place, and utilization rope saw below anchor ear and below longitudinal apron piece, blocks former pile foundation respectively.
6) after processing, water all kinds of reinforcing bars in node, comprise that main muscle spreading and the stirrup in former pile foundation encrypted, comprise the Punching Shear muscle overlap joint in apron piece and overlapped by lacing wire.(in the headspace of longitudinal apron piece, the main muscle of colligation pile body also overlaps with the main muscle of former pile body, winding screw stirrup on the main muscle of pile body, after water Punching Shear muscle in beam the main muscle overlap joint of upside with longitudinal apron piece be set in node space, after water the interior muscle 36 overlapping with the main muscle of downside of longitudinal apron piece of being undercuted in beam that arranges of node space 4.)
7) be subject to comparatively difficulty of spatial limitation concrete vibrating, thus after water in node and should build slightly expanded concrete, to guarantee its density.After concrete reaches prescribed strength, removal top lift step by step, completes by the stressed conversion of underpinned pile.
8) to each velamen underpinned pile, more than repeating, underpin operation, the entirety that finally completes all bridge pile foundations initiatively underpins.If personnel's equipment is sufficient and have enough work planes, the underpinning construction of many bridge pile foundations can carry out simultaneously, effectively the reduction of erection time.
In a word, the present invention is compared with traditional pile foundation underpinning scheme, and the new stake number of its required laying is less, has avoided being subject to steric requirements to limit the difficulty that cannot lay out pile; Stressed transduction pathway is clear and definite,, is finally delivered in each new stake according to this by longitudinal apron piece, horizontal apron piece by the upper load of underpinned pile; The integral rigidity of apron piece is larger in length and breadth, is conducive to adjust each by the relative settlement between underpinned pile; For bearing the bridge pile foundation of large-tonnage load, that after employing, waters steel bar concrete underpins node Transfer of Shear, and its stress performance and durability are comparatively reliable.
The foregoing is only preferred embodiment of the present invention, all equalizations of doing according to the present patent application the scope of the claims change and modify, and all should belong to covering scope of the present invention.