CN213448541U - Arch bridge foundation of limestone foundation under deep round gravel layer - Google Patents
Arch bridge foundation of limestone foundation under deep round gravel layer Download PDFInfo
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- 235000019738 Limestone Nutrition 0.000 title claims abstract description 42
- 239000006028 limestone Substances 0.000 title claims abstract description 42
- 239000011150 reinforced concrete Substances 0.000 claims abstract description 40
- 239000002689 soil Substances 0.000 claims abstract description 15
- 238000005056 compaction Methods 0.000 claims abstract description 8
- 239000004567 concrete Substances 0.000 claims description 36
- 229910000831 Steel Inorganic materials 0.000 claims description 14
- 239000010959 steel Substances 0.000 claims description 14
- 238000009412 basement excavation Methods 0.000 claims description 10
- 238000010276 construction Methods 0.000 abstract description 71
- 238000011065 in-situ storage Methods 0.000 abstract 1
- 230000002787 reinforcement Effects 0.000 description 30
- 238000000034 method Methods 0.000 description 10
- 238000005553 drilling Methods 0.000 description 9
- 239000011435 rock Substances 0.000 description 9
- 230000008569 process Effects 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 239000004576 sand Substances 0.000 description 6
- 238000005452 bending Methods 0.000 description 5
- 235000019994 cava Nutrition 0.000 description 5
- 238000004873 anchoring Methods 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 238000009933 burial Methods 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 229910001294 Reinforcing steel Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000002452 interceptive effect Effects 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 210000002421 cell wall Anatomy 0.000 description 1
- 239000011083 cement mortar Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
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- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
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- 239000003673 groundwater Substances 0.000 description 1
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- 238000003801 milling Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
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Abstract
The utility model discloses a limestone ground arch bridge basis under deep round gravel layer, fill soil and apron including pit shaft formula interlock pile wall, guan liang, annular waist rail, check shape pile wall basis, bottom plate, hunch seat, compaction, except that the compaction is filled soil and is cast in situ reinforced concrete component, wherein constitute foundation ditch envelope by pit shaft formula interlock pile wall, guan liang, annular waist rail, provide construction space and environment for the construction of bottom plate, hunch seat, compaction fill soil and apron to do the side wall on arch bridge basis concurrently. Accordingly, the inventor also establishes a corresponding construction method. The utility model discloses an arch bridge basis antidumping and anti-skidding stability good, level and vertical bearing capacity are high, and this construction method can be under deep round gravel layer limestone ground quick construction and show and reduce traditional large-span arch bridge basis construction degree of difficulty, time limit for a project and expense in the foundation.
Description
Technical Field
The utility model belongs to the technical field of foundation ditch and basic engineering design are built, especially, relate to a limestone ground arch bridge basis under deep round gravel layer.
Background
It is known that the horizontal thrust and the vertical load generated by the arch of the large-span arch bridge, particularly the extra-large-span arch bridge, are extremely large, and strict requirements are provided for the horizontal and vertical resistance and the displacement control of the arch bridge foundation. The foundation of the traditional long-span arch bridge is characterized in that a foundation rock with better integrity and high bearing capacity is selected as a bearing layer, a gravity type reinforced concrete pier foundation with huge construction volume is built to support huge vertical load and huge horizontal thrust of balance, the foundation rock burial depth cannot be too deep, the foundation is too high due to the fact that the foundation rock burial depth is too deep, the anti-overturning performance is not good, the requirement on the bearing capacity of the foundation rock is high, the deep foundation pit supporting and excavation pose serious challenges when the foundation is constructed, and the construction cost of the foundation and the deep foundation pit is high.
The shaft type underground continuous wall and reverse lining wall structure has the advantages of good soil and water retaining and seepage preventing performance, large horizontal rigidity and high bearing capacity, can be used as a part of a permanent foundation of a deep foundation pit support structure without an inner support and an anchor, and can be widely applied to design and construction of various large-span bridge deep foundations at home and abroad. However, for the limestone foundation under the deep gravel layer, the following defects exist:
(1) because the deep round gravel layer has no cohesive force, the permeability of underground water is strong, the construction of the diaphragm wall needs a large amount of slurry retaining walls, the hole is easy to collapse, extra slurry grouting reinforcement is needed to be carried out on two sides of the diaphragm wall, the slurry treatment and reinforcement cost is high, the quality is difficult to ensure, and the underground water is easy to pollute.
(2) The basement rock limestone layer is hard in texture, common underground diaphragm wall grooving machinery is difficult to construct, hard rock needs to be dug through double-wheel milling and crushing, construction speed is low, efficiency is low, and construction period is affected.
(3) The inner lining wall needs to be poured in sections (generally each section is 1.0-2.5m) along with layered excavation by adopting the reverse method, after each section needs to be maintained to reach the design strength, the inner lining wall can be excavated downwards for one section of pouring construction, the construction procedures are multiple, the construction period is long, the horizontal rigidity of the flat inner lining wall serving as the annular supporting member during excavation of the foundation pit is relatively small, the reinforcement ratio is high, the steel content is high, and the construction is uneconomical.
(4) The limestone foundation is often accompanied by karst, various small and medium karst caves in a certain range under and around the arch bridge foundation are usually filled with low-grade plastic plain concrete or cement mortar to construct the diaphragm wall and the foundation, and the karst treatment cost is high.
Based on the reasons, the foundation design and construction complexity, the construction difficulty and the construction cost of the large-span arch bridge are greatly increased. However, reducing the cost and saving the investment are continuous pursuits of engineering construction. In order to solve and reduce the cost for constructing the large-span arch bridge foundation in the deep coverage area, the Chinese patent application applies ' an annular underground continuous wall foundation of the large-span arch bridge in the deep coverage area ' (patent application No. 201910473506.7 published as 2019-08-23) ' adopts the traditional annular underground continuous wall and the reverse lining wall as the enclosure structure of the foundation construction and also a part of the permanent foundation, and sets a foundation slab at the bottom of the foundation pit of the annular underground continuous wall enclosure structure, in order to reduce the excavation depth of the foundation pit, the foundation slab is supported by a dense pile foundation embedded into a rock stratum, and then an arch socket is constructed to form a combined foundation with strong anti-overturning and anti-overturning performances and excellent horizontal and vertical bearing performances. The foundation utilizes the excellent compression resistance of a large amount of intensive rock-socketed pile foundations under the bottom plate to bear huge vertical load transmitted by a bridge arch structure and good bending resistance to resist bending moment generated by horizontal thrust so as to balance the horizontal thrust, but the integral rigidity of the independent pile foundations under the bottom plate is relatively low, so that the pile foundation is large in reinforcement amount and high in cost. In addition, the construction of a large-span arch bridge foundation on a limestone foundation under a deep gravel layer still has the problems of the adoption of an underground continuous wall foundation.
In order to solve the problems that the construction period is long, the construction is difficult to be carried out, the construction cost is high and the quality is difficult to ensure when the underground continuous wall foundation is adopted to construct a large-span arch bridge foundation for the limestone foundation under the deep round gravel layer, and meanwhile, the bearing performance of the foundation is required to be met, and a new foundation form is urgently required to be researched and developed. The bored secant pile is an underground continuous pile wall type foundation pit enclosure structure formed by mutually cutting and secant-connecting a reinforced concrete pile reinforced by a circular reinforcement cage and a reinforced concrete pile reinforced by a special-shaped reinforcement cage or mutually cutting and secant-connecting a reinforced concrete pile reinforced by a circular reinforcement cage and a plain concrete pile, which is formed in the present year, has excellent soil retaining, water stopping and seepage preventing functions and larger bending rigidity, and has lower manufacturing cost and higher construction speed than an underground continuous wall. With the progress of the technology, a rotary construction process is adopted, the rotary steel sleeve is used for cutting soil bodies, various soft and hard rock stratums and pile bodies constructed in advance in the construction process, the pile bodies are used as retaining walls, no slurry retaining walls and no pollution and underground water risks exist, and the rotary steel sleeve is particularly suitable for limestone foundations with karst cave development. The box foundation is a compensation foundation with huge horizontal and vertical rigidity, can reduce the bearing capacity of the foundation or the bearing capacity requirement of the pile foundation under the foundation, and is widely applied to high-rise buildings, but is not applied to arch bridge foundations at present. How to combine the two to meet the stress and deformation control requirements of the large-span arch bridge foundation of the limestone foundation underlying the deep gravel layer and obviously reduce the foundation construction difficulty and cost is a problem which is deeply researched.
Disclosure of Invention
The to-be-solved technical problem of the utility model is to provide an anti-overturning and anti-sliding stability is good, level and vertical bearing capacity are high and the construction is quick, the degree of difficulty is less, the time limit for a project reduces, the deep round gravel layer limestone foundation arch bridge basis of expense reduction.
In order to solve the technical problem, the utility model discloses a following technical scheme:
the arch bridge foundation comprises a shaft type secant pile wall, a crown beam, an annular waist beam, a lattice-shaped pile wall foundation, a bottom plate, an arch support, compaction filling and a cover plate, wherein the shaft type secant pile wall is a cylindrical underground continuous pile wall type foundation pit enclosure structure formed by alternately arranging plain concrete piles as I-sequence piles and reinforced concrete piles as II-sequence piles and mutually cutting, secting and connecting the plain concrete piles and the reinforced concrete piles; the crown beam is a reinforced concrete ring beam which is post-cast on the top surface of the shaft type secant pile wall; the annular waist beam is a post-watering flat reinforced concrete annular beam which is arranged at a certain distance along with the excavation of the foundation pit and fixedly connected to the inner side wall of the shaft type secant pile wall; the lattice-shaped pile wall foundation is a lattice-shaped occlusion pile wall foundation which is arranged below the bottom plate, fixedly connected with the bottom plate and embedded into a limestone layer, and is formed by alternately arranging plain concrete piles and reinforced concrete piles as second-order piles and mutually cutting and occluding the plain concrete piles and the reinforced concrete piles; the bottom plate is a reinforced concrete raft plate arranged at the bottom of the pit in the shaft type secant pile wall, the bottom of the raft plate is fixedly connected with the lattice type pile wall foundation, and the side surface of the raft plate is fixedly connected with the inner wall of the shaft type secant pile wall; the arch support is a separated reinforced concrete base which is fixedly connected with the bottom plate and used for fixing arch ribs, and two lateral surfaces of the arch support along the bridge direction are fixedly connected with the inner wall of the shaft type secant pile wall; the cover plate is a plate type or beam plate type reinforced concrete member fixedly connected with the crown beam and the side surface of the arch support and used for covering the opening part of the foundation pit of the shaft-barrel type secant pile wall; and a cavity between the bottom plate and the cover plate in the shaft type secant pile wall is backfilled by adopting gravel soil and compacted to form compacted filling soil.
The lattice pile wall foundation is in a lattice configuration formed by mutually engaging and connecting I-sequence piles and II-sequence piles and is engaged and connected with the shaft type engaged pile wall; the specific arrangement mode of the I-sequence piles and the II-sequence piles in the lattice-shaped pile wall foundation is that 1I-sequence pile and 1 II-sequence pile are alternately arranged and mutually cut and meshed or 1 II-sequence pile is arranged in every other I-sequence pile in a pile wall formed by mutually cutting and meshed connection of a row of I-sequence piles.
The height of the cross section of the crown beam is 0.6-1.2 times of the diameter of the shaft type secant pile wall at the beam bottom, and the width of the crown beam is 1.0-2.0 times of the diameter of the shaft type secant pile wall at the beam bottom.
The height and the width of the cross section of the annular waist beam are respectively 0.8-1.5 times and 1.0-5.0 times of the pile diameter of the shaft type secant pile wall, and the annular waist beams are arranged at intervals of 3.0-10.0m from the jacking of the crown beam along with the layered excavation of the foundation pit.
The bottom plate is a reinforced concrete raft plate with the thickness of 3.0-8.0m and taking the round gravel layer as a bearing layer; the latticed pile wall foundation is anchored into the bottom plate by 50-100mm and fixedly connected together.
The arch support is a separated reinforced concrete base with the height of 8-25m and the width of 5-15m and used for fixing the arch rib of the concrete filled steel tube of the arch bridge.
The cover plate is a plate or beam-slab reinforced concrete member, and the plate thickness is 0.2-1.0 times of the height of the crown beam.
The method for constructing the arch bridge foundation of the limestone foundation under the deep round gravel layer comprises the following steps:
(1) constructing foundation of shaft type secant pile wall and lattice pile wall: the construction method comprises the following steps of leveling a site, building a shaft type occlusive pile wall and a latticed pile wall foundation guide wall, adopting a full-casing full-rotary drilling machine to drill holes along the guide wall according to pile positions and successively pour I1 piles and I2 piles on two sides of II 1 piles, then adopting the full-casing full-rotary drilling machine to drill holes and cut the I1 piles and the I2 piles, pouring II 1 pile concrete after the holes are formed, then adopting the same construction method to construct I3 piles, then constructing II 2 piles and … …, and circularly constructing I-sequence piles and II piles in such a way until the shaft type occlusive pile wall and latticed pile wall foundation construction is completed;
(2) construction of a crown beam: breaking a guide wall, chiseling out the super-poured concrete of the pile top of the shaft cylinder type secant pile wall, binding a crown beam reinforcement framework on the pile top of the shaft cylinder type secant pile wall, anchoring a shaft cylinder type secant pile wall reinforcement cage into a crown beam with the diameter not less than 35 times of the reinforcement diameter, reserving a pre-buried cover plate reinforcement joint, pouring crown beam concrete and maintaining to the designed strength; the detailed size of the crown beam is determined by foundation pit support calculation; the shaft barrel type secant pile wall is further reinforced and connected into a whole through a crown beam;
(3) constructing an annular waist rail: excavating foundation pits step by step to reach the bottom elevation of the annular waist beam in a layered mode, pouring the annular waist beam in a lane mode, and determining the detailed size of the annular waist beam at different depths of the foundation pits according to foundation pit supporting calculation; excavating the foundation pit to the bottom elevation of the first annular waist beam step by step, layer by layer and symmetrically, drilling holes along the inner wall of the shaft type secant pile wall pile for planting ribs and binding an annular waist beam reinforcement framework, pouring first annular waist beam concrete, after the first annular waist beam concrete reaches the design strength, continuously excavating the foundation pit downwards to the bottom elevation of the next annular waist beam step by step, layer by layer and symmetrically excavating the foundation pit to the bottom elevation of the next annular waist beam, constructing a second annular waist beam, and circulating the construction until the construction of all the annular waist beams is completed;
(4) bottom plate construction: continuously excavating the foundation pit to the designed pit bottom elevation, chiseling out pile top laitance of the latticed pile wall foundation, keeping the pile reinforcement anchoring of the second-order pile of the latticed pile wall foundation into the bottom plate to be not less than 35 times of the reinforcement diameter, drilling along the inner wall of the shaft type secant pile wall pile, implanting the bottom plate and the connecting reinforcement of the shaft type secant pile wall inner wall, binding the bottom plate reinforcement and the pre-buried reserved arch center vertical connecting reinforcement, pouring bottom plate concrete in layers and maintaining to the designed strength;
(5) and (3) arch support construction: binding an arch support steel bar framework, reserving a horizontal connecting steel bar of a pre-buried cover plate, reserving a pre-buried arch bridge arch rib steel pipe, pouring arch support concrete in a layered mode, and maintaining to design strength;
(6) compacting and filling construction: after the bottom plate and the arch support reach the design strength, sand gravel is filled in the foundation pit in a layered mode and compacted until the bottom elevation of the cover plate is designed;
(7) cover plate construction: and binding cover plate reinforcing steel bars, pouring cover plate concrete and maintaining to the designed strength.
In the step <1 >: the bored pile for the well-barrel type occlusive pile wall is a bored pile of a full-casing full-rotation construction process, the diameter of the bored pile is 0.8m-2.0m, the embedded complete limestone is not less than 2m, and the bored pile comprises an underground continuous pile wall formed by connecting I-sequence piles and II-sequence piles with the same pile diameter in an interactive occlusion way by 150mm-400 mm.
In the step <1 >: the lattice type pile wall foundation adopts a bored pile of a full-casing full-rotation construction process, the diameter of the bored pile is 0.8-2.0m, the embedded complete limestone is not less than 1m, and the lattice type underground continuous pile wall comprises a lattice type underground continuous pile wall formed by connecting I-sequence piles and II-sequence piles which are positioned in a compact round gravel layer and have the same pile diameter and are alternately occluded by 150-400mm and connecting the I-sequence piles by 150-400 mm; the connection mode of the lattice-shaped pile wall foundation and the shaft type interlocking pile wall is mutual cutting interlocking connection, and the interlocking amount is 150-400 mm.
Aiming at the problems of large foundation burial depth, difficult construction and high cost caused by high bearing capacity requirement of a deep round gravel layer underlying bedrock foundation large-span arch bridge foundation, the inventor designs a deep round gravel layer underlying limestone foundation arch bridge foundation which comprises a shaft type secant pile wall, a crown beam, an annular waist beam, a latticed pile wall foundation, a bottom plate, an arch support, compacted filling soil and a cover plate, wherein the compacted filling soil and the reinforced concrete members are cast-in-place, the shaft type secant pile wall, the crown beam and the annular waist beam form a foundation pit enclosure structure, construction space and environment are provided for the construction of the bottom plate, the arch support, the compacted filling soil and the cover plate, and the foundation pit enclosure structure is also used as an arch bridge foundation side wall. Accordingly, the inventor also establishes a corresponding construction method. The utility model discloses an arch bridge basis antidumping and anti-skidding stability good, level and vertical bearing capacity are high, and this construction method can be under the thick circle gravel layer of clamp fast construction in the limestone ground and show and reduce traditional large-span arch bridge basis construction degree of difficulty, time limit for a project and expense.
Compared with the prior art, the utility model discloses an outstanding advantage specifically lies in:
(1) the utility model discloses a grey rock foundation arch bridge basis under deep and thick circle gravel layer includes pit shaft formula interlock pile wall, the crown beam, annular waist rail, the pile foundation, the bottom plate, the hunch seat, the cylindric underground pile case raft combination basis that compaction fill and apron mutual rigid coupling formed, need not to excavate to complete limestone, through pit shaft formula interlock pile wall and lattice type interlock pile wall embedding complete limestone, the poor and not enough characteristics of bulk rigidity of pile foundation wholeness that dispersion set up under the bottom plate has been overcome, it is good to have the wholeness, vertical tension and compression rigidity and horizontal bending rigidity are big, horizontal shear resistance is strong, the characteristics that antidumping and anti-sliding stability are good, lattice type lattice pile wall basis utilizes the powerful ability shear of concrete to resist horizontal thrust under the raft board to resist horizontal thrust, overcome independent foundation pile utilization bending resistance under the bottom plate and resist horizontal thrust and lead to the shortcoming that the arrangement of reinforcement rate is high, can satisfy the huge horizontal bearing capacity and the vertical bearing capacity requirement of foundation huge span of stride arch bridge arch structure to the basis and the causticity and its extremely big The requirement of displacement control solves the difficult problems of designing and building the foundation of the large-span super-span arch bridge with the deep sand pebbles under the limestone foundation.
(2) The utility model discloses a gridwork foundation arch bridge foundation under deep round gravel layer adopts pit shaft formula interlock pile wall, the crown beam, the foundation ditch retaining structure that annular waist rail formed, it is big to have horizontal rigidity and hoop rigidity, it is good to keep off native stagnant water impermeability performance, the work progress does not have mud dado and mud and handles, need not extra cell wall reinforcement, it need not the ground to inevitable middle-size and small-size solution cavity department and handles, can solve to press from both sides deep sand cobble and become that the gridwork foundation ditch groundwater permeability is strong, the easy hole of collapsing of sand cobble leads to retaining structure concrete to irritate excessively and the construction quality scheduling problem that should not guarantee, and can be under construction fast, can satisfy arch bridge foundation construction space and environmental requirement, and foundation ditch retaining structure can regard as permanent foundation structure's partly, can reduce arch bridge foundation to build foundation ditch retaining structure's expense and construction period by a wide margin.
Drawings
Fig. 1 is a schematic plan view of the arch bridge foundation of the limestone foundation under the deep round gravel layer.
Fig. 2 is a side elevation (cross-sectional view along the bridge) of the arch bridge foundation of the limestone foundation underlying the deep gravel layer of the present invention.
Fig. 3 is a front vertical plane (cross-sectional view) of the arch bridge foundation of the limestone foundation under the deep round gravel layer.
Fig. 4 is a schematic view of the interlocking connection and construction sequence of the shaft type interlocking pile wall and lattice pile wall foundation in the deep round gravel layer underlying limestone foundation arch bridge foundation of the utility model.
In the figure: 1 pit shaft formula secant pile wall, 2 crown beam, 3 annular waist roof beam, 4 lattice pile wall foundations, 5 bottom plates, 6 hunch seats, 7 compaction fill, 8 apron, 9 arch rib, 11I preface stake (serial number is I1 respectively according to the construction order, I2, I3, … …), 12 II preface stake (serial number is II 1 respectively according to the construction order, II 2, II 3, … …).
Detailed Description
A, basic structure
As shown in fig. 1 to 4, the arch bridge foundation of the limestone foundation under the deep round gravel layer of the present invention includes a shaft type secant pile wall, a crown beam, an annular waist beam, a lattice pile wall foundation, a bottom plate, an arch support, a compaction filling and a cover plate. Wherein,
the shaft-barrel type secant pile wall is a cylindrical underground continuous pile wall type foundation pit enclosure structure formed by alternately arranging plain concrete piles (concrete piles) as I-sequence piles and reinforced concrete piles as II-sequence piles and mutually cutting, secant and connecting the plain concrete piles and the reinforced concrete piles, wherein both the I-sequence piles and the II-sequence piles are embedded into a limestone layer; the top beam is a reinforced concrete ring beam which is post-cast on the top surface of the shaft type secant pile wall, so that the shaft type secant pile wall is connected to form an integral enclosure structure with higher rigidity and is used as a first horizontal ring support of a foundation pit supporting structure; the annular waist beam is a post-cast horizontal reinforced concrete ring beam fixedly connected to the inner side wall of the shaft type secant pile wall and arranged at a certain distance along with excavation of the foundation pit, and is used as a horizontal ring support of the shaft type secant pile wall foundation pit support structure; the lattice-shaped pile wall foundation is a lattice-shaped occlusion pile wall foundation which is arranged below a bottom plate, fixedly connected with the bottom plate and embedded into a limestone layer, and is formed by arranging 1I-sequence pile and 1 II-sequence pile alternately and mutually cutting and occluding or arranging 1 II-sequence pile every other I-sequence pile in a pile wall formed by mutually cutting and occluding a row of I-sequence piles; the bottom plate is a reinforced concrete raft plate at the bottom of the pit in the shaft type secant pile wall, the bottom of the raft plate is fixedly connected with the lattice type pile wall foundation, and the side surface of the raft plate is fixedly connected with the inner wall of the shaft type secant pile wall; the arch support is a separated reinforced concrete base which is fixedly connected with the bottom plate and used for fixing arch ribs, and two lateral surfaces of the arch support along the bridge direction are fixedly connected with the inner wall of the shaft type secant pile wall; the cover plate is a plate type or beam plate type reinforced concrete member fixedly connected with the crown beam and the side surface of the arch support and used for covering the opening part of the shaft type secant pile wall foundation pit; and filling sand gravel and compacting and filling soil in a cavity between the bottom plate and the cover plate in the shaft type secant pile wall.
The shaft-barrel-type secant pile wall is formed by alternately arranging I-order piles and II-order piles, mutually cutting and secant to connect cylindrical foundation side walls, and is used as a foundation pit enclosure structure during construction.
The lattice pile wall foundation is in a lattice configuration formed by mutually engaging and connecting I-sequence piles and II-sequence piles and is engaged and connected with the shaft type engaged pile wall; the specific arrangement mode of the I-sequence piles and the II-sequence piles in the lattice-shaped pile wall foundation is that 1I-sequence pile and 1 II-sequence pile are alternately arranged and mutually cut and meshed or 1 II-sequence pile is arranged in every other I-sequence pile in a pile wall formed by mutually cutting and meshed connection of a row of I-sequence piles.
The thickness of the cross section of the crown beam is 0.6-1.2 times of the diameter of the shaft type secant pile wall at the bottom of the crown beam, and the width of the crown beam is 1.0-2.0 times of the diameter of the shaft type secant pile wall at the bottom of the crown beam. The height and the width of the cross section of the annular waist beam are respectively 0.8-1.5 times and 1.0-5.0 times of the pile diameter of the shaft type secant pile wall, and the annular waist beams are arranged at intervals of 3.0-10.0m from the jacking of the crown beam along with the layered excavation of the foundation pit. The bottom plate is a reinforced concrete raft plate with the thickness of 3.0-8.0m and taking the round gravel layer as a bearing layer; the latticed pile wall foundation is anchored into the bottom plate by 50-100mm and fixedly connected together. The arch support is a separated reinforced concrete building base with the height of 8-25m and the width of 5-15 m. The cover plate is a plate or beam-slab reinforced concrete member, and the plate thickness is 0.2-1.0 times of the height of the crown beam.
Second, construction method
(1) Constructing foundation of shaft type secant pile wall and lattice pile wall: according to the hydrogeological conditions of a proposed site, the geometrical parameters of an arch bridge foundation and a foundation pit engineering, the structural stress and the stability requirement of the foundation pit, designing and calculating all technical parameters required by a long-span steel pipe concrete arch bridge foundation of a limestone foundation under a deep round gravel layer, drawing a design drawing, leveling the site, constructing a shaft type occlusive pile wall and a lattice pile wall foundation guide wall according to the design requirement, adopting a full-casing full-rotary drilling machine to drill holes along the guide wall according to pile positions and pour I sequence piles (I1 pile and I2 pile) at two sides of a II sequence pile (II 1 pile), then adopting the full-casing full-rotary drilling machine to drill holes and cut the I1 pile and the I2 pile, pouring concrete of the II sequence pile (II 1 pile), then adopting the same construction method to construct the I sequence pile (I3 pile), then constructing the II sequence pile (II 2 pile), … …, and thus circularly constructing the I sequence pile and the II pile, until the foundation construction of the shaft type secant pile wall and the lattice pile wall is completed; adopting a steel sleeve retaining wall of a rotary machine in the process of forming the hole of the shaft type secant pile wall and the lattice pile wall foundation, pouring concrete in the sleeve after the hole is formed, and pulling out the sleeve; at the limestone with large-volume karst caves, the sleeve can penetrate through the karst caves and is embedded into the complete limestone at the bottom of the karst caves, concrete is poured into the sleeve to form a pile body, and the filling treatment of the karst caves is not needed;
the shaft-type secant pile wall is a drilling secant cast-in-place pile wall constructed by adopting a full-casing full-rotation construction process, the diameter of a cast-in-place pile is 0.8-2.0m, the embedded complete limestone is not less than 2m, and the underground continuous enclosure pile wall is formed by connecting I-sequence piles and II-sequence piles with the same pile diameter in an interactive cutting and meshing mode of 150-400 mm. The reinforcement quantity of the second-order piles is determined according to the water and soil pressure outside the pit during the construction of the foundation pit and the horizontal thrust of the arch bridge during the use;
the lattice-shaped pile wall foundation is a drilled and occluded cast-in-place pile wall constructed by adopting a full-casing full-rotation construction process, the diameter of the cast-in-place pile is 0.8-2.0m, the embedded complete limestone is not less than 1m, and the lattice-shaped underground continuous pile wall foundation comprises I-sequence piles and II-sequence piles which are positioned in a compact round gravel layer and have the same pile diameter, wherein the I-sequence piles and the II-sequence piles are alternately cut and occluded by 150-sequence piles and 400-sequence piles are connected to form a lattice-; the connection mode of the lattice pile wall foundation and the shaft type interlocking pile wall is mutual cutting interlocking connection, and the interlocking amount is 150-400 mm;
(2) construction of a crown beam: breaking a guide wall, chiseling out the super-poured concrete of the pile top of the shaft cylinder type secant pile wall, binding a crown beam reinforcement framework on the pile top of the shaft cylinder type secant pile wall, anchoring a shaft cylinder type secant pile wall reinforcement cage into a crown beam with the diameter not less than 35 times of the reinforcement diameter, reserving a pre-buried cover plate reinforcement joint, pouring crown beam concrete and maintaining to the designed strength; the detailed size of the crown beam is determined by foundation pit support calculation; the shaft barrel type secant pile wall is further reinforced and connected into a whole through a crown beam;
(3) constructing an annular waist rail: excavating foundation pits step by step and layer to the bottom elevation of the annular waist beam, pouring the annular waist beam in a lane, and calculating and determining the detailed sizes of the annular waist beam at different depths of the foundation pits according to the support of the foundation pits; excavating the foundation pit to the bottom elevation of the first annular waist beam step by step, layer by layer and symmetrically, drilling holes along the inner wall of the shaft type secant pile wall pile for planting ribs and binding an annular waist beam reinforcement framework, pouring first annular waist beam concrete, after the first annular waist beam concrete reaches the design strength, continuously excavating the foundation pit downwards to the bottom elevation of the next annular waist beam step by step, layer by layer and symmetrically excavating the foundation pit to the bottom elevation of the next annular waist beam, constructing a second annular waist beam, and circulating the construction until the construction of all the annular waist beams is completed; the annular waist beam is fixedly connected with the inner wall of the shaft type secant pile wall through the embedded steel bars to form a foundation pit enclosure structure with huge horizontal rigidity and annular rigidity;
(4) bottom plate construction: continuously excavating the foundation pit to the designed pit bottom elevation, chiseling out pile top laitance of the latticed pile wall foundation, keeping the pile reinforcement anchoring of the second-order pile of the latticed pile wall foundation into the bottom plate to be not less than 35 times of the reinforcement diameter, drilling along the inner wall of the shaft type secant pile wall pile, implanting the bottom plate and the connecting reinforcement of the shaft type secant pile wall inner wall, binding the bottom plate reinforcement and the pre-buried reserved arch center vertical connecting reinforcement, pouring bottom plate concrete in layers and maintaining to the designed strength; the bottom plate construction can be carried out without excavating a complete limestone layer, and the bottom surface of the bottom plate is positioned on the top surface of the compact round gravel layer or is slightly lower than the top surface of the compact round gravel layer;
(5) and (3) arch support construction: binding an arch support steel bar framework, reserving a horizontal connecting steel bar of a pre-buried cover plate, reserving a pre-buried arch bridge arch rib steel pipe, pouring arch rib concrete in a layered mode, and maintaining to design strength;
(6) compacting and filling construction: after the bottom plate and the arch support reach the design strength, sand gravel is filled in the foundation pit in a layered mode and compacted until the bottom elevation of the cover plate is designed;
(7) cover plate construction: and binding cover plate reinforcing steel bars, pouring cover plate concrete and maintaining to the designed strength.
Claims (6)
1. The utility model provides a deep round gravel layer underlying limestone foundation arch bridge basis, includes pit shaft formula secant pile wall, crown beam, annular waist rail, lattice pile wall basis, bottom plate, hunch seat, compaction fill out and apron, its characterized in that: the shaft-barrel type secant pile wall is a cylindrical underground continuous pile wall type foundation pit enclosure structure formed by alternately arranging plain concrete piles as I-sequence piles and reinforced concrete piles as II-sequence piles and mutually cutting, secant and connecting the plain concrete piles and the reinforced concrete piles; the crown beam is a reinforced concrete ring beam which is poured on the top surface of the shaft type secant pile wall in a post-pouring mode; the annular waist beam is a post-watering flat reinforced concrete annular beam which is arranged at a certain distance along with the excavation of the foundation pit and fixedly connected to the inner side wall of the shaft-type secant pile wall; the lattice-shaped pile wall foundation is a lattice-shaped occlusion pile wall foundation which is arranged below the bottom plate, fixedly connected with the bottom plate and embedded into a limestone layer, and is formed by alternately arranging plain concrete piles and reinforced concrete piles as second-order piles and mutually cutting and occluding the plain concrete piles and the reinforced concrete piles; the bottom plate is a reinforced concrete raft plate arranged at the bottom of the pit in the shaft type secant pile wall, the bottom of the raft plate is fixedly connected with the lattice type pile wall foundation, and the side surface of the raft plate is fixedly connected with the inner wall of the shaft type secant pile wall; the arch support is a separated reinforced concrete base which is fixedly connected to the bottom plate and used for fixing arch ribs, and two lateral surfaces of the arch support along the bridge direction are fixedly connected to the inner wall of the shaft type secant pile wall; the cover plate is a plate type or beam plate type reinforced concrete member fixedly connected with the crown beam and the side surface of the arch support and used for covering the opening part of the foundation pit of the shaft-barrel type secant pile wall; and a cavity between the bottom plate and the cover plate in the shaft type secant pile wall is backfilled by adopting gravel soil and compacted to form compacted filling soil.
2. A deep pebble layer underlying limestone foundation arch bridge foundation as claimed in claim 1 wherein: the first-order piles and the second-order piles in the lattice pile wall foundation are connected in an occlusion mode to form a lattice configuration and are connected with the shaft type occlusion pile wall in an occlusion mode; the specific arrangement mode of the I-sequence piles and the II-sequence piles in the lattice-shaped pile wall foundation is that 1I-sequence pile and 1 II-sequence pile are alternately arranged at intervals and are mutually cut and meshed with each other or 1 II-sequence pile is arranged at intervals in a pile wall formed by mutually cutting and meshed with one row of I-sequence piles.
3. A deep pebble layer underlying limestone foundation arch bridge foundation as claimed in claim 1 wherein: the height of the cross section of the crown beam is 0.6-1.2 times of the diameter of the shaft type secant pile wall at the beam bottom, and the width of the crown beam is 1.0-2.0 times of the diameter of the shaft type secant pile wall at the beam bottom.
4. A deep pebble layer underlying limestone foundation arch bridge foundation as claimed in claim 1 wherein: the height and the width of the cross section of the annular waist beam are respectively 0.8-1.5 times and 1.0-5.0 times of the pile diameter of the shaft type secant pile wall, and the annular waist beams are arranged at intervals of 3.0-10.0m from the top of the crown beam along with the layered excavation of the foundation pit.
5. A deep pebble layer underlying limestone foundation arch bridge foundation as claimed in claim 1 wherein: the bottom plate is a reinforced concrete raft plate with the thickness of 3.0-8.0m and taking the round gravel layer as a bearing layer; the latticed pile wall foundation is anchored into the bottom plate by 50-100mm and fixedly connected together.
6. A deep pebble layer underlying limestone foundation arch bridge foundation as claimed in claim 1 wherein: the arch support is a separated reinforced concrete base which is 8-25m high and 5-15m wide and used for fixing the arch rib of the concrete-filled steel tube arch bridge; the cover plate is a plate or beam-slab reinforced concrete member, and the plate thickness is 0.2-1.0 times of the height of the crown beam.
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| CN202020907912.8U CN213448541U (en) | 2020-05-26 | 2020-05-26 | Arch bridge foundation of limestone foundation under deep round gravel layer |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111485571A (en) * | 2020-05-26 | 2020-08-04 | 广西交科集团有限公司 | Arch bridge foundation of limestone foundation under deep round gravel layer and construction method thereof |
| CN114875929A (en) * | 2022-04-25 | 2022-08-09 | 中建八局第三建设有限公司 | Inner support-free construction method suitable for ultra-large circular deep foundation pit |
-
2020
- 2020-05-26 CN CN202020907912.8U patent/CN213448541U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111485571A (en) * | 2020-05-26 | 2020-08-04 | 广西交科集团有限公司 | Arch bridge foundation of limestone foundation under deep round gravel layer and construction method thereof |
| CN114875929A (en) * | 2022-04-25 | 2022-08-09 | 中建八局第三建设有限公司 | Inner support-free construction method suitable for ultra-large circular deep foundation pit |
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