CN212270945U - Existing railway line foundation pit supporting system - Google Patents

Abstract

The utility model relates to a railway engineering existing line construction technical field specifically is a railway existing line foundation pit support system, including other existing lines cross the line foundation pit support, after the steel beam miniaturely that the existing railway line was erect through the fulcrum stake was built on the shelf track above the foundation pit, after the part was put the slope and was slotted below the track, in limited space height, adopt the machinery to draw the pipe pore-forming, the back slip casting double miniature steel pipe campshed, the upper end of double miniature steel pipe campshed is poured with the crown beam, carries out foundation pit support through above-mentioned double miniature steel pipe campshed support system; the foundation pit supporting system is low in construction difficulty and operation cost, small in operation influence caused by surrounding environments such as underground water level and soil quality, capable of saving construction period to a large extent, small in overhead range, small in excavation and backfill amount, high in operation efficiency and low in safety risk.

Description

Existing railway line foundation pit supporting system

Technical Field

The utility model relates to a railway engineering existing line construction technical field specifically is a railway existing line excavation supporting system, including other existing lines cross circuit excavation supporting.

Background

Taking the areas of Hubei and Henan as examples, when the ascending and descending main lines of the Jingguang railway are operated below without stopping, the underpass tunnel construction is carried out, a beam erecting and jacking method and an overhead large slope digging and excavating method are generally adopted, and the construction environment and the operation conditions are analyzed: the 2 construction methods are generally suitable for field construction and field environments with jacking and overhead large slope excavation conditions, are used as Kyoho lines, are abnormally busy in operation, have no jacking construction conditions in narrow construction areas, and have no overhead large slope excavation construction due to the influence of surrounding environments during construction in railway passenger stations; and (3) analyzing from a construction period: the construction speed of the underpass constructed by the overhead jacking method is low, if the underpass meets a rock barrier, the jacking construction needs to be broken, the underpass passing through the Jingguang line is generally in a city or suburb, the buried depth is shallow, blasting construction conditions are not generally met, for the overhead large-scale slope excavation method, the overhead range, namely the overhead length, is doubled to doubled, a large amount of excavation and backfilling are carried out, the transportation difficulty is high in the urban soil excavation operation, and the construction cannot be carried out in rainy days; from the safety quality analysis: for the construction of an overhead jacking method, the disturbance to a soil body is large, particularly, a roadbed is inevitably sunk after jacking is completed, and the settlement and tamping compaction are required for a long period of time, so that for the construction of the overhead large-scale slope enlarging method, although the safety risk is low, the backfill quality is difficult to ensure due to a large amount of high backfill amount, and the backfill construction period is long; analysis from economic comparisons: for the construction of an overhead jacking method, a pushing device needs to be manufactured, the manufacturing cost is high, for an overhead large slope-enlarging excavation method, although the supporting cost is saved, the overhead range is large, backfill is generally difficult to agree to adopt, and the price of a large amount of graded sandstone is also high; the manual hole digging pile which is usually adopted has low efficiency, cannot be constructed when meeting the geology with high underground water level, and has large safety risk.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a railway existing line excavation supporting system to solve the problem that proposes in the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme: the foundation pit supporting system for the existing railway line comprises a foundation pit and is characterized in that after a steel beam erected on an existing railway line through a fulcrum pile is erected on a track in a small range, after a slope is locally set up and a groove is formed below the track, in a limited space height, a mechanical guide pipe is adopted for hole forming, double rows of miniature steel pipe piles are subjected to post grouting, crown beams are poured at the upper ends of the double rows of miniature steel pipe piles, and foundation pit supporting is carried out through the double rows of miniature steel pipe pile supporting system.

Preferably, the side slope surface of the foundation pit is provided with a spray anchor support.

Preferably, the fulcrum piles have a diameter of 2 meters and a length of 14 meters.

Preferably, two rows of steel pipes are arranged in the double-row miniature steel pipe row pile, the distance between the two rows of steel pipes is 1 meter, and concrete is poured into the pipe holes of the steel pipes and outside the pipe holes.

Preferably, the diameter of the steel pipe of the double-row miniature steel pipe row pile is 219mm, the wall thickness of the steel pipe is 8.0 mm, holes of 10 mm are drilled in the pipe wall of the steel pipe, and the distance between every two adjacent groups of holes is 1.5 m.

Preferably, the crown beam is connected with two rows of steel pipes.

Compared with the prior art, the beneficial effects of the utility model are that:

according to the foundation pit supporting system for the existing railway, after a small-range overhead track is used for locally placing a slope and grooving below the track, mechanical hole forming is adopted in the limited space height, and steel pipe row piles are used for foundation pit supporting; the foundation pit structure is low in construction difficulty and operation cost, small in operation influence caused by surrounding environments such as underground water level and soil quality, capable of saving construction period in a large range, small in overhead range, small in excavation and backfill amount, high in operation efficiency and low in safety risk.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural view of the present invention;

in the drawings, the components represented by the respective reference numerals are listed below:

the foundation pit is 1, the fulcrum pile is 2, the steel beam is 3, the double-row micro steel pipe row pile is 4, the crown beam is 5, and the tunnel is 6.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

Example one

Referring to fig. 1, the present invention provides a technical solution: the foundation pit supporting system for the existing railway line comprises a foundation pit 1 and is characterized in that fulcrum piles 2 are poured on two sides of the foundation pit 1, steel beams 3 are erected at the upper ends of the fulcrum piles 2, double rows of miniature steel pipe row piles 4 are arranged on two sides of the foundation pit, crown beams 5 are poured on the upper ends of the double rows of miniature steel pipe row piles 4, and a tunnel 6 is arranged between the two groups of crown beams 5.

Wherein, the side slope surface of foundation ditch 1 is equipped with the shotcrete and props up.

Wherein, the diameter of the fulcrum pile 2 is 2 meters, and the length is 14 meters.

Wherein, be equipped with two rows of steel pipes in the double miniature steel pipe campshed 4, the interval of two rows of steel pipes is 1 meter, and two rows the depth direction interval of steel pipe is 500 millimeters, and the downthehole and the outside pipe hole of steel pipe all are filled with the concrete.

Wherein, the diameter of the steel pipe of the double-row micro steel pipe row pile 4 is 219mm (the wall thickness is 8.0 mm), and the pipe wall of the steel pipe is drilled with 10 mm holes.

Wherein the crown beam 5 is connected with two rows of steel pipes.

Example two

Overview of engineering

A newly-built passenger outbound tunnel of a horseman shop is characterized in that the central mileage K882+799.5 of a Beijing broadcasting line is 10.2 meters in width of a tunnel body, 7.7 meters in buried depth and 3.7 meters in net height, and the tunnel passes through 4 tracks (namely, a LaoJingguang uplink line, a downlink line, an uplink line to a departure line and a downlink line to the departure line) and 2 platforms. A side stair entrance and a side stair entrance are arranged on the second platform, the entrance and the exit are 3.7 meters wide and 3.3 meters high; the basic platform is not provided with an entrance, and the width of the main hole body under the basic platform is narrowed to 7.2 meters and connected with the station house.

Principle of scheme

Firstly, adopting manual excrement digging beam buttress among 2 tracks and outside the tracks of a railway, making 4 steel rails overhead by a railway excrement beam D24 (with 24-meter span) by using a rail car and a beam erecting machine, and then adopting a small excavator to carry out the steps of 1:1.5 slope excavation is carried out to form a U-shaped groove with the depth of 3.5 meters (the net height under a track is 3.5 meters) and the width of 14 meters, a crawler-type spiral drilling machine with the height of a modified mast being 3 meters is adopted to drill a hole with the depth of 9 meters in a channel, steel pipes with the diameter of 219 millimeters and the wall thickness of 8.0 millimeters are guided into the hole 3 times, holes with the diameter of 10 millimeters are drilled on the wall of the steel pipe, the distance between two adjacent groups of holes is 1.5 meters, then pressure grouting equipment is utilized to perform grouting from the bottom of a pile hole, so that cement slurry is fully distributed on the inner side and the outer side of the steel pipe hole to form a steel pipe row pile support, 2 rows of holes are arranged on each side, the distance is 1 meter, 2 rows of holes are connected by adopting reinforced concrete crown.

Third, scheme design

Overhead design: the finished railway steel product with the span of 24 meters is used for erecting the bridge, and the buttress adopts a bored pile with the diameter of 2 meters and the length of 14 meters and adopts a 1:1.5 slope.

Designing the miniature steel pipe pile: each side of a tunnel body is provided with 2 rows of piles @1000, each side is supported by adopting a diameter of 219mm (the wall thickness is 8.0 mm) @500 double-row micro steel pipe row piles and one phi 609 steel pipe, and the steel pipe piles are filled with cement paste by adopting an underwater construction method.

Third, the construction sequence

The first step is as follows: applying for the ascending and descending slow-moving points of a Beijing Guangdong line Ma shop station to a railway general company, allowing the points to pass within 45 kilometers, then manually digging a pier pile of the steel temporary beam, and erecting the steel temporary beam after the maintenance period reaches the designed strength;

the second step is that: the main hole body is excavated to 3.5 m depth by adopting a first stage according to 1:1.5 slope-laying excavation to form a U-shaped channel, and the side slope is subjected to spray anchor construction;

the third step: constructing double rows of miniature steel pipe row piles and high-pressure jet grouting piles on the main hole body, and carrying out slope setting and layered excavation on an entrance and an exit to a crown beam and a support bottom to carry out crown beam and corner brace construction;

the fourth step: excavating the second stage to the height of the bottom of the cushion layer in a layering manner (inserting spray anchors among piles in the excavation engineering);

the fifth step: and digging the elevator foundation pit, the collector well and other parts until the residual distance reaches 300mm, and manually cleaning the bottom (performing cushion layer construction in time).

And a sixth step: constructing a main structure of the hole body;

the seventh step: backfilling between the hole body structure and the pile, backfilling the top of the hole body, and tamping and compacting;

eighth step: and (5) dismantling the steel temporary beam.

Overhead construction method and process

The beam erecting process is carried out according to a four-step construction sequence, namely, the track gauge is adjusted: the distance between the sleepers of the existing line is adjusted according to the distance of 670mm, and the redundant sleepers are extracted, and the process is bound to enhance the maintenance work of the line. Positioning the cross beam; removing partial ballast in the adjusted space between the sleepers and penetrating the ballast into a cross beam, positioning the cross beam by using positioning angle steel S7, simultaneously cushioning a rubber pad, mounting a steel rail fastener, and in the process of penetrating the cross beam, a large insulating rubber plate needs to be cushioned below one steel rail to prevent a track circuit from being short-circuited to influence signals and travelling cranes; the (II) track cross beam penetrates from the (4) track to the two platform directions, and the (I) track cross beam penetrates from the two platforms to the one platform direction. Positioning the longitudinal beam: and removing the ballast at the two ends of the beam and outside the beam (drawing a groove between two lines to the bottom of the longitudinal beam), manually matching with a rail crane to block the key points of the line, hoisting the longitudinal beam in place, mounting a connecting plate and a bracket, temporarily loosening the steel rail fastener on the steel beam, and fixing the steel rail fastener after the connection between the longitudinal beam and the beam is finished. The mounting position of the overhead longitudinal beam is 1990mm away from the central line of the track, the height of the beam top of the beam is 749mm higher than the height of the rail surface, and the limit requirement is 1875mm (see a lower limit diagram), so that the limit requirement in railway technical management regulations is met. Installing the oblique lever, all the connecting systems, the slag blocking pieces and the like. The square timber is arranged in the center of the line, and the iron wire is used for binding the concrete sleeper to the timber, so that the concrete sleeper is prevented from falling to hurt people after excavation construction. The angle steel with the angle of 180mm multiplied by 180mm is pre-buried at the top of the bored pile, the wall thickness is 18mm, the pre-buried depth of the angle steel is 100cm, the exposed height is 30cm, the main purpose is to limit the transverse movement of the longitudinal beam, meanwhile, the longitudinal beam is utilized to provide support reaction force for the bored pile, the anti-overturning stability of the pile is improved, and the angle steel and the longitudinal beam are tightly plugged by mixed wood.

Five-dimensional and miniature steel pipe pile construction method and process

The method comprises the steps of site leveling, steel pipe manufacturing, measurement and setting-out, pitch positioning, drilling by a drilling machine in place, hole cleaning, steel pipe placement, grouting by a grouting machine and orifice grouting.

1) Leveling the field by using a 50-type forklift; releasing a side line of the foundation pit and determining a pile position according to design requirements, and installing a drilling machine to perform hole forming operation; after the construction is finished, the slurry is transported out of the construction area, and the pile is inspected and protected.

2) And (3) manufacturing and welding a grouting steel pipe: and (4) blanking according to the depth required by the design drawing, and performing reinforced welding on the joint of the steel pipes.

3) And (3) measurement and paying-off: and measuring and paying off according to the space and the row pitch required by the design and the elevation provided by the design.

4) Pitch positioning: and (4) using chopsticks to be driven underground for positioning according to the designed hole diameter, space and row spacing.

5) Positioning the miniature pile: the process adopts a dry hole forming mode to drill holes, positions are carried out according to the micro piles, a geological drilling machine is accurately positioned at the hole forming position, and square timbers are padded under the automobile supporting legs after tamping to ensure the stability of the drilling machine.

6) Drilling in place: placing the automobile-carried geological drilling rig at a specified position, and placing the automobile-carried geological drilling rig horizontally to prevent inclination; lifting the drill rod to the side of the drilling machine, starting the drilling machine, and slowly drilling; and (3) connecting a drill rod once every 2m of depth until the designed effective depth is obtained.

7) Drilling: before drilling, the steel pipe is lengthened according to the requirement of a design scheme, the lap joint part needs to be reinforced by 12 steel bars for welding, the welding length is not less than twice of the diameter of the steel pipe, the welding seam is full, the verticality of the steel pipe needs to be checked, a welder has to have a welder certificate, and trial welding is needed before welding; the end part of the pile tip is welded into a closed tip shape, and a grout outlet is drilled in the range of less than 2.5 meters below the pile tip, the diameter is 15mm, the distance is 500mm, and grout outlet holes are arranged in a quincunx staggered manner.

8) Hole cleaning: before injecting the slurry, cleaning the pile hole to discharge the slurry in the hole, wherein the thickness of the sediment at the bottom of the hole is required to be not more than 50 mm.

9) Installing and lowering the steel pipe: after the hole is cleaned, a prefabricated steel pipe is timely installed in the hole, and a 100mm PVC pipe is sleeved on the steel pipe and is exposed out of the ground by 200mm, so that a grouting pipe can be conveniently connected.

10) And (3) installation of a grouting machine: and fixing a grouting machine at a designated position on site, connecting a power supply through a designated distribution box, adopting a 6-square three-phase five-wire system cable, putting the mixed cement slurry into a 1m x 1m ash trough which is made by welding 6mm steel plates, and then grouting by the grouting machine. And (3) installing a pressure gauge on the grouting pipe, controlling the grouting pressure to be 0.5Mpa and the water-cement ratio to be 0.45-0.5, temporarily not pulling the grouting pipe after grouting until cement slurry flows out of the grouting pipe, pulling out the grouting pipe, sealing the end part of the steel pipe, pressurizing for several minutes, and waiting until the cement slurry flows out of the steel pipe again.

11) Installing a grouting pipe: after the steel pipe is placed, grouting needs to be conducted in time, the grouting pipe is connected to the steel pipe in the lower inlet hole through the grouting machine, the connector needs to be connected in a sealing mode, and the grouting pipe is conveyed through the rubber pipe.

12) Mixing cement paste: and (3) mixing the cement paste by adopting a special machine, controlling the water cement ratio to be 0.45-0.5, putting the mixed cement paste into a steel-made 1m x 1m cement groove, and then grouting by a grouting machine.

13) Grouting cement slurry: and (3) installing a pressure gauge on the grouting pipe, controlling the grouting pressure to be 0.5Mpa and the water-cement ratio to be 0.45-0.5, temporarily not pulling the grouting pipe after grouting until cement slurry flows out of the grouting pipe, pulling out the grouting pipe, sealing the end part of the steel pipe, pressurizing for several minutes, and waiting until the cement slurry flows out of the steel pipe again.

14) Multiple pressurizing and grouting: because the requirement of filling coefficient is difficult to obtain by one-time grouting, the obtained grouting pressure is 0.5Mpa, and multiple times of clearance grouting, generally three to five times, are needed until the grout is turned over at the orifice.

Sixthly, the requirement of quality safety

1) During the construction of the miniature pile, the hole depth, the length of the steel pipe and the length of the grouting pipe are carefully measured, so that the phenomenon of pile breakage of a false pile is avoided.

2) And strictly controlling the elevation of the pile top and the pile bottom.

3) The diameter of the micro pile is 300mm, and the thickness of the built-in steel pipe is 219mm (the wall is 8.0 mm). Within 2.5 m of the lower part of the grouting steel pipe, grout outlet holes are distributed at intervals of 400mm in a quincunx shape, and the diameter of each grout outlet hole is 15 mm.

4) Slurry water-cement ratio 0.5: 1, the consumption of the cement P.O42.5 is not less than 40 kg per meter.

5) The first grouting pressure is 0.4-1.0 Mpa and is kept for 3 minutes to ensure that the pressure breaks the adhesive tape, so that the grout is extruded out of the pipe and is fully injected into the pile body. The pressure of the second grouting is not less than 1.5Mpa, and the interval time between the two grouts is not less than 1.5-4 hours.

6) Pile position deviation at two ends is not more than 1/3 pile diameter (1/3 is 100mm), pile position deviation in the middle is not more than 1/2 pile diameter (1/2 is 300 is 150mm), and perpendicularity is not more than 1/1000 pile length (1/1000 is 9 is 1000 is 9 mm).

7) Before the construction of the miniature steel pipe piles, technical crossing and safe crossing are carried out on each team, so that each worker can firmly establish quality and safety consciousness.

8) During grouting, the grouting pipe is not required to be bent and wound, and attention is paid to the pressure gauge all the time so as to prevent the pipe with too high pressure from hurting people.

9) The field plugging and unplugging grouting pipe personnel are provided with protective eyes so as to prevent the slurry from splashing into the eyes.

10) After the grouting of each pile is finished, the grouting pipe is kept at the pressure for 3 minutes, and the grouting pipe is pulled out after the pressure is dissipated, so that the grouting effect is facilitated, the quality of the pile body is ensured, and safety accidents caused by overhigh pressure are avoided.

The utility model discloses a structure is practiced thrift through in the channel engineering that rebuilds engineering passenger in Beijing Guangdong line on the horse shop station of standing, gains fine effect, has guaranteed the time limit for a project. Is worth popularizing and using in similar projects.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best understand the invention for and utilize the invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims (6)

1. The utility model provides a railway existing line foundation pit support system, includes foundation ditch (1), its characterized in that, the both sides of foundation ditch (1) are poured into fulcrum stake (2), just roof beam (3) are erect to the upper end of fulcrum stake (2), the foundation ditch both sides are equipped with double miniature steel pipe campshed (4), the upper end pouring of double miniature steel pipe campshed (4) has hat roof beam (5), sets up between two sets of hat roof beams (5) ground way (6).

2. The existing railway line foundation pit supporting system of claim 1, wherein the slope surface of the foundation pit (1) is provided with a spray anchor support.

3. A existing railway line foundation pit supporting system as claimed in claim 1, wherein the fulcrum piles (2) are 2m in diameter and 14 m in length.

4. The existing railway line foundation pit supporting system as claimed in claim 1, wherein two rows of steel pipes are arranged in the double rows of miniature steel pipe row piles (4), the distance between the two rows of steel pipes is 1 meter, and concrete is poured into the pipe holes of the steel pipes and outside the pipe holes.

5. The existing railway line foundation pit supporting system as claimed in claim 4, wherein the diameter of the steel pipe of the double-row miniature steel pipe row pile (4) is 219mm, the wall thickness is 8.0 mm, the wall of the steel pipe is drilled with 10 mm holes, and the distance between two adjacent groups of holes is 1.5 m.

6. A foundation pit supporting system for existing railway line according to claim 4, characterized in that the said crown beam (5) connects two rows of steel pipes.

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