CN113847069A - Underground excavation subway station of suspension type station hall layer and independent rail traveling area and construction method thereof - Google Patents

Abstract

A suspended type station hall layer and an underground excavation subway station of an independent rail running area and a construction method thereof are disclosed, wherein the station is composed of a main body part and an auxiliary part, the main body part comprises a station hall layer, a downlink channel, an air channel and a station platform layer, the auxiliary part comprises an external equipment room, the station platform layer is composed of a rail running area tunnel and an exchange channel, the rail running area tunnel is divided into an uplink rail running area tunnel and a downlink rail running area tunnel according to the driving direction of the subway, the uplink rail running area tunnel and the downlink rail running area tunnel are arranged in parallel at longitudinal intervals of the subway driving, the exchange channels are a plurality of and are arranged at transverse intervals, rock pillars are respectively arranged between the exchange channels, and the station hall layer is suspended on two sides above the station platform layer and is independently divided into two suspended halls in the longitudinal direction; therefore, the invention overcomes the traditional defects, has better structural overall mechanical property, can flexibly avoid underground pipelines near stations or peripheral important building structures, can flexibly arrange different areas of the stations according to local conditions, and is simple and efficient.

Description

Underground excavation subway station of suspension type station hall layer and independent rail traveling area and construction method thereof

Technical Field

The invention relates to the technical field of urban subway station building structures, in particular to a subsurface excavation subway station of a suspension type station hall layer and an independent rail traveling area and a construction method thereof.

Background

Subways are used as an important component of urban rail transit modes, and play an increasingly positive role in passenger traffic of dense-population cities. Because the subway appears to solve the urban traffic jam and fill up the blank of urban traffic speed, the subway station is often required to be constructed in downtown areas. However, in terms of the construction method, if the open excavation method is adopted, traffic jam in downtown areas is inevitably aggravated, so the underground excavation method is usually adopted for construction in downtown areas.

The common station main body is generally of an integrated double-layer structure, wherein the underground layer is a station hall layer, and the underground layer is a station platform layer. The structure is integral and unsegmentable, the construction method is single, the structure is limited by landform and geological conditions, and the influence on the surrounding environment is large.

Generally, the subway line in the platform range of the subway station should be kept horizontal, and if drainage and other reasons exist, the gradient should not exceed 2 per thousand. Therefore, for the traditional integrated station, the longitudinal two ends of each layer are basically located at the same elevation. However, in some hilly and mountain areas, such as Chongqing and Qingdao, the relief is large, and the slope of the urban road is large, which will result in large difference of the ground elevation of the entrance and exit at the two ends when the subway is built

1. Because each layer elevation of the general integral type undercut station keeps the level basically, the station burial depth is controlled by the low relief, when the big or small mileage end relief difference of the station is great, the whole burial depth of the station is great, and because the existence of the relief difference, the difference of the burial depths of the two ends is great. For example, assuming a ground slope of 5%, for a subway station with a longitudinal direction of 200m, the elevation will differ by 10m, and since the elevation is consistent throughout the lobby floor, the entrance burial depth will differ by 10 m. According to the subway design specification requirement, the inclination angle of the escalator at the entrance and exit of the station is not more than 30 degrees, and when the buried depths of two ends of the station are different by 10m, the length of the entrance and exit is different by more than 20 m. Meanwhile, the burying depth of the station layer of the station per se can be larger for the purpose of civil air defense or the limitation of overall planning and the like, for the end with larger burying depth, the entrance and exit used for entering and exiting the ground can exceed 100m, which is not beneficial to the evacuation and riding efficiency of passengers, and according to the standard requirement, the entrance and exit exceeding 100m needs to take the measures capable of meeting the fire-fighting evacuation requirement, which increases the engineering quantity and the economic cost.

2. When the integral double-layer station is constructed by adopting the underground excavation method, the cross section span is large, and large deformation is easily generated to cause structural failure, so that strong support is needed during construction, the whole construction risk is large, the difficulty is large, and the cost is high. Meanwhile, the space utilization rate is low, and the functional partitions cannot be reflected on the structure, so that the partitions are not clear enough, economic and environment-friendly.

3. For urban construction dense areas, peripheral underground building structures and underground pipelines are more, and the traditional integrated double-layer station cannot be flexibly avoided, so that the peripheral building structures and the pipelines need to be changed, and the economy is poor.

Therefore, in view of the above-mentioned drawbacks, the present inventors have conducted extensive research and design to overcome the above-mentioned drawbacks by designing and developing an underground excavated subway station for a suspended type station hall floor and an independent rail-bound section and a construction method thereof, based on the experience and results of the related industries for a long time.

Disclosure of Invention

The invention aims to provide a suspended type station hall layer and an underground excavated subway station of an independent rail running area and a construction method thereof, which overcome the three defects of difficult site selection, difficult construction, unclear internal structure and better structural overall mechanical property caused by large and inseparable volume of the traditional integrated double-layer station, can flexibly avoid peripheral underground pipelines and other constructions, can keep the lengths of the entrances and exits at two ends to be equal under the condition of poor terrain, and avoids the overlong condition.

In order to achieve the purpose, the invention discloses a suspended type station hall layer and an underground excavated subway station of an independent rail zone, which consists of a main part and an auxiliary part, wherein the main part comprises a station hall layer, a downlink channel, an air duct and a station layer, the auxiliary part comprises an external equipment room, the station layer consists of a rail zone tunnel and an exchange channel, the air duct is used as a boundary at two ends of the station layer, and a subway interval line is arranged at the outer side of the air duct, and the underground excavated subway station is characterized in that:

the rail running region tunnel is divided into an uplink rail running region tunnel and a downlink rail running region tunnel according to the subway running direction, the uplink rail running region tunnel and the downlink rail running region tunnel are arranged in parallel at a longitudinal interval of the subway running, the uplink rail running region tunnel and the downlink rail running region tunnel both comprise a rail running region and a waiting region for the subway running, and the exchange channel is transversely arranged and is orthogonal to the uplink rail running region tunnel and the downlink rail running region tunnel;

the exchange channels are arranged in a plurality of transverse intervals and at least comprise an exchange channel A, an exchange channel B and an exchange channel C, rock pillars are respectively arranged among the exchange channels, so that the rock pillars replace the upright posts of the traditional island type station as a supporting structure,

the station hall layer is hung on two sides of the upper side of the station layer and is independently divided into an A station hall and a B station hall in the longitudinal direction, wherein the A station hall and the station layer are hung at intervals, and the B station hall is hung in a rock-soil layer above the station layer.

Wherein: the two ends of the platform layer are respectively communicated with the air duct A and the air duct B, and a circuitous air duct and a control room are arranged in the air duct A and the air duct B.

Wherein: the air duct is divided into an air duct interlayer and a station layer air duct, the air duct A comprises a station hall air duct interlayer, the air duct B comprises another air duct interlayer, a fresh air duct and an exhaust duct are respectively arranged in the station hall layer air duct interlayer and the another air duct interlayer, the station layer air duct of the air duct A comprises a circuitous air duct and a safety control room, and the station layer air duct of the air duct B comprises a ventilation air-conditioning electric control room.

Wherein: the entrance structure, the air duct and the station hall layer are all of composite lining structures, composite lining is adopted at the crossing positions of the tunnel in the rail-mounted area and the cavern, single-layer anchor-spraying support is adopted for the middle section, and permanent spray-anchoring support is adopted for the exchange channel.

Wherein: the connection between the station hall layer and the station layer is realized through a downlink channel, and the connection between the station hall layer and the outdoor ground is realized through an entrance.

Wherein: the middle position of the station hall A is connected to the station hall downlink channel A through the station hall downlink channel straight section, the station hall downlink channel A is obliquely arranged and is internally provided with a staircase, and the middle of the station hall downlink channel straight section is provided with an accessible elevator channel.

Wherein: the middle position of the B station hall is connected to a B station hall downlink channel through a B station hall downlink channel straight section, and the B station hall downlink channel is obliquely arranged and is internally provided with a staircase.

Also discloses a construction method of the underground excavation subway station of the suspension type station hall layer and the independent rail traveling area, which is characterized by comprising the following steps:

the method comprises the following steps: constructing a vertical shaft from the air duct, drilling vertical shafts at the air ducts at two ends, and starting construction at the same time;

step two: constructing an air duct A and a station hall A from a temporary vertical shaft at the end A by adopting a CRD method, excavating by dividing into a plurality of blocks according to the height, wherein the length of a step excavated at each step is about 5-7m, erecting a grid steel frame and a temporary support after each step of excavation is finished, starting secondary lining in time after primary support is stable, excavating an air duct B from the temporary vertical shaft at the end B by adopting a step method, wherein the length of the step excavated at each step is 5-7m, and starting secondary lining in time after primary support is stable;

step three: constructing a C exchange channel by a step method, carrying out secondary lining by C45 concrete, and carrying out advanced pre-support and grouting for a large pipe shed and a small pipe to reinforce the stratum;

step four: constructing an exchange channel A by adopting a step method, carrying out permanent spray anchor support, constructing an exchange channel B by adopting the step method, and carrying out permanent spray anchor support;

step five: excavating an outlet and an inlet of the B end by adopting a method combining open excavation and underground excavation, and starting the construction and the laying of the station hall B from the outlet and the inlet of the B end;

step six: when the station B hall is excavated to the bottom elevation of the straight section of the downlink channel of the station B hall, the straight section of the downlink channel of the station B hall is constructed by a step method;

step seven: and after finishing secondary lining in the station hall, the air duct and the exchange channel and reaching the design strength, reversely constructing the downlink channel from bottom to top by adopting a CRD (cross section dimension) method or a step method according to the section dimension and the geological condition.

Wherein: in the second step: after the construction and the support of the air ducts at the two ends are finished, simultaneously, respectively opening holes from the circuitous air duct of the air duct station layer at the A end, the safety control room and the ventilation and air conditioning electric control room of the air duct station layer at the B end to construct towards the middle by adopting a full-section method, excavating an upper-track-area tunnel, stopping construction at the B end when the distance between the tunnel faces at the two ends is 20m, and tunneling the A end to be through;

and simultaneously, respectively opening holes from the circuitous air duct of the air duct station layer at the A end, the safety control room and the ventilation and air conditioning electric control room of the air duct station layer at the B end, starting construction towards the middle by adopting a full section method, excavating a tunnel in a down-track area, stopping construction at the B end when the distance between the tunnel faces at the two ends is 20m, and tunneling and communicating the A end.

Wherein: the fifth step comprises the following substeps:

step 5.1: the method comprises the following steps of (1) openly excavating an entrance from an entrance ground opening, wherein the length of the entrance of an openly excavated section is 2m, and the enclosure structure is constructed by adopting a smooth method in the form of a steel pipe pile, an anchor cable and a rib beam;

step 5.2, open excavation is carried out until the light and shade excavation junction is reached, and downward excavation meets the requirement of a pipe shed construction space; driving a self-advancing pipe shed into the arch part along the outer contour of the underground excavated section; plugging the tunnel face after entering the tunnel for 3-5 m;

step 5.3: then adopting a CD method or a CRD method to continuously excavate the foundation pit downwards to the substrate;

step 5.4: and excavating the B station hall by adopting a middle tunnel method from the B end entrance and exit base, advancing the large pipe shed and the small pipe to carry out pre-support by means of advanced grouting, and carrying out construction and laying of the B station hall by adopting a vertical slope retaining and longitudinal slab staggering construction method.

From the above, the underground excavation subway station of the suspension type station hall layer and the independent rail traveling area and the construction method thereof have the following effects:

1. underground pipelines or peripheral important building structures near the station can be flexibly avoided, different areas of the station can be flexibly arranged according to local conditions, different construction methods can be selected, and simplicity and high efficiency are realized;

2. for the area with large height difference on the ground, the positions of station hall layers and entrances and exits at two ends of the underground station can be reasonably arranged by means of the height difference formed by the terrain, so that the crowd evacuation pressure caused by the terrain difference can be effectively relieved, and the engineering scale is reduced.

3. The novel underground excavation station has the advantages that the functions of all areas of the station are clear, the layout is clear, passengers can easily identify the entrance and exit directions, and the residence time of the passengers is shortened.

4. According to the invention, the traditional integrated large-scale station is structurally changed into a plurality of relatively independent small-scale building units on the aspect of building size, so that the whole building is more stable in structure, the construction risk can be obviously reduced, and the tunnel support parameters can be greatly weakened, thereby reducing the engineering investment and achieving the economic effects of low carbon and environmental protection.

The details of the present invention can be obtained from the following description and the drawings.

Figure illustrates the drawings

Fig. 1 shows a schematic structural view of a suspended type station hall layer and a subsurface excavated subway station of an independent rail traveling zone of the present invention.

FIG. 2 shows a three-dimensional model of a subject of the present invention.

Fig. 3 shows a plan view of a lobby floor of the present invention.

Fig. 4 shows a plan view of the station level of the present invention.

Fig. 5 shows a longitudinal section a-a in fig. 3.

Fig. 6 shows a longitudinal section B-B in fig. 3.

Figure 7 shows a cross-sectional view C-C in figure 3.

Fig. 8 shows a cross-sectional view D-D in fig. 3.

Fig. 9 shows a cross-sectional view E-E in fig. 3.

FIG. 10 shows a geological profile of passageway A of the present invention.

FIG. 11 shows a geological profile of the port B of the present invention.

Fig. 12 shows a construction sequence chart of the present invention.

And (3) labeling of the graph:

1-station hall layer; 11-A station hall; 12-B station hall; 2-a downlink channel; 21-A station hall downlink channel; 211-A station hall descending channel straight section; 22-B station hall downlink channel; 221-B station hall downlink channel straight section; 23-an unobstructed hoistway; 3-an air duct; 31-A end air duct; 32-B end air duct; 311-station hall typhoon air duct interlayer; 312-a circuitous air duct; 313-a safety control room; 321-air duct interlayer; 322-ventilation air-conditioning electric control room; 4-a switching channel; a 41-A switching channel; a 42-B switch channel; a 43-C exchange channel; 5-a track area tunnel; 51-an upstream trackbound region tunnel; 52-descending rail-bound region tunnel; 54-track area; 53-waiting area; 511 c-uplink interval tunnel; 521 c-downlink interval tunnel; 6-plug-in equipment room; 7-a rock pillar; 8-entrance and exit; an inlet and an outlet at the end 81-A; and 82-B end inlet and outlet.

Detailed Description

Referring to fig. 1 to 11, there are shown underground excavated subway stations of a suspended lobby floor and an independent rail road section of the present invention.

The underground excavation subway station of the suspension type station hall layer and the independent rail traveling area is composed of a main body part and an auxiliary part, wherein the main body part comprises a station hall layer 1, a descending channel 2, an air duct 3 and a station layer, the auxiliary part comprises an external equipment room 6, the external equipment room is shown in the figure 2 and the figure 4, the station layer is composed of a rail traveling area tunnel 5 and an exchange channel 4, the air duct 3 is used as a boundary at two ends of the station layer, and a subway interval line is arranged outside the air duct 3.

Further, the rail-bound region tunnel 5 can be divided into an ascending rail-bound region tunnel 51 and a descending rail-bound region tunnel 52 according to the subway running direction, the ascending rail-bound region tunnel 51 and the descending rail-bound region tunnel 52 are arranged in parallel at longitudinal intervals of the subway running, both the ascending rail-bound region tunnel 51 and the descending rail-bound region tunnel 52 comprise a rail-bound region 54 and a waiting region 53 for the subway running, the interchange passage 4 is transversely arranged and is orthogonal to the ascending rail-bound region tunnel 51 and the descending rail-bound region tunnel 525, the ground elevation of the interchange passage 4 is consistent with the ground elevation of each waiting region 53, and therefore the interchange passage 4 and the waiting region 53 jointly form a station layer for passengers to get on and off.

Two ends of the platform layer are respectively communicated through an A air duct 31 and a B air duct 32, and a circuitous air duct and a control room are arranged in the A air duct 31 and the B air duct 32.

Specifically, referring to fig. 5, the air duct 3 may be divided into two portions, namely, an air duct interlayer and a platform layer air duct, the air duct 31 a includes a platform air duct interlayer 311, the air duct 32B includes another air duct interlayer 321, a fresh air duct and an exhaust duct are respectively disposed in the platform air duct interlayer 311 and the other air duct interlayer 321, the platform layer air duct of the air duct 31 a includes a circuitous air duct 312 and a safety control room 313, and the platform layer air duct of the air duct 32B includes an electric control room 322 of a ventilation air conditioner.

Because the areas such as the platform layer, the trackway area, the air channel and the like are generally arranged in a large integral plane in the traditional station, a section with an ultra-large span is dug in the construction process, a center pillar is usually required to be completed as a support to reduce the accumulated deformation of the structure, then the center pillar is excavated in a distributed mode, and finally the stand column is used as the support of the upper structure, so that the construction method is difficult and high in cost.

In order to overcome the defects of the technical scheme, the invention divides each region of the platform layer into small-section caverns, and referring to a platform layer plan view shown in fig. 3, the platform layer has certain similarity with the traditional island type station, the exchange channels 4 are arranged in a plurality of transverse intervals and at least comprise an A exchange channel 41, a B exchange channel 42 and a C exchange channel 43, and rock pillars 7 are respectively arranged among the exchange channels, so that the rock pillars 7 replace the upright columns of the traditional island type station to serve as a supporting structure, the green environmental protection concept is met, the economic cost is reduced, and the transverse cross section shown in fig. 7 shows that the transverse span of each cavern is smaller, the full-section construction can be adopted in a stable hard rock stratum, the construction is simple and efficient, and the construction risk is reduced.

Furthermore, although the invention avoids the construction of large sections, the invention relates to the construction of the crossed group holes of the small-section tunnel.

Specifically, in one embodiment, the access structure, the air duct and the station hall layer can all adopt a composite lining structure, for the uplink and downlink tunnels, the composite lining can be adopted only at the intersection of two ends related to the cavern because of large buried depth and small section, and for the middle section, single-layer anchor-spraying support can be adopted, but a space with two linings is reserved in the middle section, so that secondary lining is needed after convenience is provided. The exchange channel has larger buried depth and smaller span, and can be permanently supported by a spray anchor. Generally, for the intersection of the caverns, the cavern occupies the whole longitudinal distance 1/10 from the intersection, and the cavern should be timely supported after excavation and needs to be subjected to composite lining.

Further, referring to fig. 3 and 5, the station hall layer 1 is suspended and arranged on two sides above the station layer and is divided into two halls, namely an a station hall 11 and a B station hall 12, in the longitudinal direction, wherein the a station hall 11 and the station layer are suspended and separated by a station hall air duct interlayer 311, the B station hall 12 is suspended in a rock layer above the station layer, and optionally, the elevation of the a station hall 11 is not consistent with the elevation of the B station hall 12, but the burial depth is consistent. The station hall suspension type structure specially designed by the invention can enable the structure form of the station to be more flexible and changeable, and as seen from a longitudinal section, the station hall which is separately suspended is smaller in size, the suspension position can be relatively freely selected in the height direction and the longitudinal and horizontal directions, and when the terrain and the underground space environment are more complex, the suspension type station hall with a small section can more easily select the arrangement position, so that the structure of the station is more uniform and reasonable, and the utilization rate of the underground space is greatly improved.

Further, the station hall layer 1 generally exists as a public area, and is a transition buffer area between the station layer and the outdoor ground, in this embodiment, the connection between the station hall layer 1 and the station layer is realized through the downlink channel 2, and the connection between the station hall layer 1 and the outdoor ground is realized through the gateway 8.

Specifically, the middle position of the A station hall 11 is connected to the A station hall downlink channel 21 through the A station hall downlink channel straight section 211, the A station hall downlink channel 21 is obliquely arranged and is internally provided with a building escalator, the middle of the A station hall downlink channel straight section 211 is provided with an accessible elevator channel 23, passengers can selectively take an accessible elevator to reach a C exchange channel 43 right below the A station hall 211 or reach an A exchange channel 41 connected with the lower end of an inclined channel through the building escalator, and then enter a waiting area from the exchange channel to realize riding.

Similarly, the middle position of the B station hall 22 is connected to the B station hall down passageway 22 through the B station hall down passageway straight section 221, the B station hall down passageway 22 is obliquely arranged and is internally provided with a building staircase, and passengers can arrive at the B exchange passageway 42 through the building staircase and then enter the waiting area to take a bus.

Therefore, the upper end and the lower end of the inclined channel are orthogonally communicated with the station hall and the exchange channel through the straight sections, and the passenger flow pressure is favorably buffered.

Further, the a station hall 11 is provided with an a end entrance 81 connected to the ground, and the B station hall is provided with a B end entrance 82 connected to the ground, so that passenger flow enters and exits the station.

The prior art scheme usually arranges the station hall layer in the same elevation plane to in station hall layer and station platform layer were arranged in a whole frame, set up the differentiation of horizontal medium plate as station platform layer and station hall layer when actual construction: the upper part of the horizontal middle plate is used as a station hall layer, and the lower part of the horizontal middle plate is used as a station platform layer. The technical scheme has two problems in some cities with large relief, which mainly take hilly and mountain lands, in the station terrain.

First, referring to fig. 1 and 11, the slope of the road surface of the embodiment of the present invention is about 3.1%, and according to the road design specification, the slope of a general urban road can reach 8% at most. The elevations of the ports 81 and 82 at both ends are shown in fig. 1 and 11, respectively, and it can be seen that the difference in elevation is about 1 m. If a traditional integrated double-layer station building mode is adopted, the entrances and exits are led out from the station hall at the same elevation, and the lengths of the two entrances and exits are different by at least 2m because the angles of the entrances and exits are not more than 3 degrees. Because the buried depth of the subway station is controlled by the low-terrain end, the entrance and the exit of the high-terrain end are generally overlong, the requirement of 'short and straight' of the entrance and the exit by the subway design specification is not met, and the passenger riding efficiency and crowd evacuation in case of emergency are not facilitated.

Secondly, there are inevitably some areas in the city where important underground pipelines are located. The traditional integrated double-layer station building is compact in form and inseparable, and only stations can be wholly avoided or peripheral pipelines can be changed when the environment complex areas are built, so that the utilization rate of underground space is low and the building cost is high.

In order to solve the above two problems of the prior art, the elevation of the station hall a is 27.86m and the burial depth is 13.81m by the specially designed suspension type arrangement of the invention, see fig. 1 and fig. 11; the elevation of the B station hall is 33.46m and the burial depth is 13m in a hanging mode at the end part of the station hall, so that A, B station halls are basically consistent in burial depth, the final length of the entrance and exit at the A end is about 26m, the length of the entrance and exit at the B end is about 33m, and the length difference of the entrances and exits at the two ends A, B is effectively shortened.

Meanwhile, because A, B station halls are separated, a vacant space of about 13m is formed between A, B station halls in the longitudinal direction, and the method can be used for setting underground pipelines or other underground structures.

Furthermore, the building form of the station is excavation according to needs, the whole volume is small, and enough space for placing equipment is probably not available, so that the external equipment room 6 is connected with the station hall A, and the visual area of the station hall A is increased. In addition, the external equipment room 6 can be provided with an additional entrance.

Referring to fig. 12, the present invention provides a supporting construction method, wherein the external hanging equipment room 6 of the auxiliary part is constructed by open cut method, and the main part is constructed by underground cut method, which comprises the following steps:

the method comprises the following steps: constructing vertical shafts from the air ducts, considering two air ducts, and making the structures of the platform layers symmetrical, and in order to shorten the construction period, drilling the vertical shafts at the air ducts at two ends and starting construction at the same time;

further, temporary shafts are excavated and supported at the air shafts at the a end of the a duct 31 and the B end of the B duct 32.

Step two: a temporary vertical shaft at the end A is used for constructing an air duct A31 and a station hall A11 by a CRD method, wherein the temporary vertical shaft can be divided into a plurality of blocks (4 blocks in the specific embodiment) according to the height for excavation, the length of a step of each excavation is about 5-7m, a grid steel frame and a temporary support are erected after each excavation is finished, secondary lining is started in time after primary support is stable, meanwhile, a temporary vertical shaft at the end B is used for excavating an air duct B32 by a step method, the length of the step of each excavation is 5-7m, and secondary lining is started in time after the primary support is stable.

Preferably, after the construction and support of the air ducts at the two ends are finished, simultaneously, holes are respectively opened from the circuitous air duct 312 of the air duct station layer at the A end, the safety control room 313 and the ventilation and air conditioning electric control room 311 of the air duct station layer at the B end, the construction is started to the middle by adopting a full-section method, the tunnel 51 of the ascending rail-bound region is excavated, when the distance between the tunnel faces at the two ends is 20m, the construction is stopped at the B end, and the A end is tunneled and communicated;

simultaneously, respectively opening holes from a circuitous air duct 312 of an A-end air duct station layer, a safety control room 313 and a ventilation and air conditioning electric control room 311 of a B-end air duct station layer to start construction towards the middle by adopting a full-section method, excavating a descending rail-mounted area tunnel 52, stopping construction at the B end when the distance between the tunnel faces at the two ends is 20m, and tunneling and communicating the A end;

and adopting spray anchor permanent support in the construction process, and driving an anti-corrosion anchor rod after excavation. And C35 high-performance synthetic fiber concrete is sprayed for preliminary support.

Furthermore, the crossing of the tunnel portal should be reinforced and supported, and composite lining is adopted, namely, for the two ends of the tunnel in the ascending and descending rail traveling region, which are communicated with the air duct 3, air duct lining steel bars should be bent into the ascending and descending tunnels and welded with the ascending and descending tunnel steel bars, secondary lining is carried out by adopting C45 concrete on the basis of spray anchor support, and the secondary lining is simultaneously molded and molded to a deformation joint.

Step three: the construction of the C exchange channel 43 is carried out by adopting a step method, because the channel is connected with the barrier-free elevator channel 23 besides the tunnel 5 of the ascending and descending rail zone, and the cross holes in the peripheral influence range are more, C45 concrete is adopted for secondary lining, and advanced pre-support and grouting of a large pipe shed and a small pipe are required for reinforcing the stratum.

Step four: the exchange passage A41 is constructed by a step method, the section size of the exchange passage A is small, the number of peripheral cross holes is small, surrounding rocks are stable, and permanent spray anchor supporting can be carried out, and the exchange passage B42 is constructed by the step method, the section size of the exchange passage A is small, the number of peripheral cross holes is small, the surrounding rocks are stable, and permanent spray anchor supporting can be carried out.

Step five: adopting a method combining open excavation and underground excavation to excavate the B-end entrance 81, starting the construction and the laying of the B station hall from the B-end entrance 81, and concretely comprising the following substeps:

step 5.1: the entrance 82 is dug from the ground opening of the entrance 82, the length of the entrance of the open-cut section is about 2m, and the enclosure structure is constructed by adopting a mode of steel pipe piles, anchor cables and rib beams.

Step 5.2, open excavation is carried out until the light and shade excavation junction is reached, and downward excavation is carried out to a certain depth to meet the requirement of a pipe shed construction space; driving a self-advancing pipe shed into the arch part along the outer contour of the underground excavated section; plugging the tunnel face after entering the tunnel for 3-5 m;

step 5.3: then, continuously excavating the foundation pit downwards to the substrate by selecting a CD method or a CRD method according to geological conditions;

step 5.4: a station B hall is excavated from a base at the entrance and exit of the end B by adopting a middle tunnel method, a large pipe shed and a small pipe are advanced for grouting to perform pre-support, and a construction method of vertical slope retaining and longitudinal platform staggering is adopted.

Step six: when the station B hall is excavated to the bottom elevation of the straight section 221 of the downlink channel of the station B hall, the straight section 221 of the downlink channel of the station B hall is constructed by a step method, and a ring of pipe shed and small pipe advance support is arranged at the intersection before construction.

Step seven: after the station hall 1, the air duct 3 and the exchange channel 4 finish the two linings and reach the design strength, the construction of the downlink channel 2 is performed reversely from bottom to top by selecting a CRD method or a step method according to the section size and the geological conditions.

Furthermore, as the group-hole construction is involved, besides the strengthening advance support measures, the primary support rigidity is strengthened in the crossing range of all the holes, the principles of firstly putting holes and then putting holes, strictly controlling excavation footage, strengthening monitoring, strictly controlling blasting vibration velocity and timely following the secondary lining construction are followed in the construction process.

Step eight: the external hanging equipment room is not a main structure of the station, but the construction mode of the external hanging equipment room is briefly described in the invention because the external hanging equipment room is connected with the station hall A of the station. The external hanging equipment room can be divided into two parts from the construction angle, wherein one part is a construction temporary vertical shaft, and the other part is an open cut foundation pit. The temporary construction vertical shaft is the end A vertical shaft in the step one, is a main construction slag hole of an end A air duct, a station main body and an interval line, is constructed firstly, the excavation depth of the vertical shaft is smaller than 1.0m, and the vertical shaft is excavated while being supported. The excavation of the foundation pit is carried out after the tunnel is firstly completed at the A end air duct, the station main body and the interval. The foundation pit support is characterized in that steel pipe pile construction is firstly carried out, then crown beam construction is carried out, and after the strength reaches 75% of the design strength, earth and stone excavation and anchor bolt support construction are carried out along the inner side of the pile in a segmented mode.

Therefore, the invention has the advantages that:

1. underground pipelines or peripheral important building structures near the station can be flexibly avoided, different areas of the station can be flexibly arranged according to local conditions, different construction methods can be selected, and simplicity and high efficiency are realized;

2. for the area with large height difference on the ground, the positions of station hall layers and entrances and exits at two ends of the underground station can be reasonably arranged by means of the height difference formed by the terrain, so that the crowd evacuation pressure caused by the terrain difference can be effectively relieved, and the engineering scale is reduced.

3. The novel underground excavation station has the advantages that the functions of all areas of the station are clear, the layout is clear, passengers can easily identify the entrance and exit directions, and the residence time of the passengers is shortened.

4. According to the invention, the traditional integrated large-scale station is structurally changed into a plurality of relatively independent small-scale building units on the aspect of building size, so that the whole building is more stable in structure, the construction risk can be obviously reduced, and the tunnel support parameters can be greatly weakened, thereby reducing the engineering investment and achieving the economic effects of low carbon and environmental protection.

It should be apparent that the foregoing description and illustrations are by way of example only and are not intended to limit the present disclosure, application or uses. While embodiments have been described in the foregoing description and illustrated in the drawings, the present invention is not limited by the illustrations and the specific examples described in the embodiments as the best mode presently contemplated for carrying out the teachings of the present invention, and the scope of the present invention is intended to include any embodiments falling within the foregoing description and the appended claims.

Claims (10)

1. The utility model provides a suspension type station room layer and undercut subway station in independent rail way district, comprises main part and accessory part, main part includes station room layer, downstream channel, wind channel and platform layer, and the accessory part includes external equipment room, the platform layer comprises rail way district tunnel and interchange passageway, the wind channel is used as the border at the both ends on platform layer, the outside in wind channel is subway interval circuit, its characterized in that:

the rail running region tunnel is divided into an uplink rail running region tunnel and a downlink rail running region tunnel according to the subway running direction, the uplink rail running region tunnel and the downlink rail running region tunnel are arranged in parallel at a longitudinal interval of the subway running, the uplink rail running region tunnel and the downlink rail running region tunnel both comprise a rail running region and a waiting region for the subway running, and the exchange channel is transversely arranged and is orthogonal to the uplink rail running region tunnel and the downlink rail running region tunnel;

the exchange channels are arranged in a plurality of transverse intervals and at least comprise an exchange channel A, an exchange channel B and an exchange channel C, and rock pillars are arranged among the exchange channels respectively, so that the rock pillars replace the upright columns of the traditional island type station to serve as a supporting structure;

the station hall layer is hung on two sides of the upper side of the station layer and is independently divided into an A station hall and a B station hall in the longitudinal direction, wherein the A station hall and the station layer are hung at intervals, and the B station hall is hung in a rock-soil layer above the station layer.

2. The underground excavated subway station of suspension type station hall layer and independent rail row area as claimed in claim 1, characterized in that: the two ends of the platform layer are respectively communicated with the air duct A and the air duct B, and a circuitous air duct and a control room are arranged in the air duct A and the air duct B.

3. The underground excavated subway station of suspension type station hall layer and independent rail row area as claimed in claim 2, characterized in that: the air duct is divided into an air duct interlayer and a station layer air duct, the air duct A comprises a station hall air duct interlayer, the air duct B comprises another air duct interlayer, a fresh air duct and an exhaust duct are respectively arranged in the station hall layer air duct interlayer and the another air duct interlayer, the station layer air duct of the air duct A comprises a circuitous air duct and a safety control room, and the station layer air duct of the air duct B comprises a ventilation air-conditioning electric control room.

4. The underground excavated subway station of suspension type station hall layer and independent rail row area as claimed in claim 1, characterized in that: the entrance structure, the air duct and the station hall layer are all of composite lining structures, composite lining is adopted at the crossing positions of the tunnel in the rail-mounted area and the cavern, single-layer anchor-spraying support is adopted for the middle section, and permanent spray-anchoring support is adopted for the exchange channel.

5. The underground excavated subway station of suspension type station hall layer and independent rail row area as claimed in claim 1, characterized in that: the connection between the station hall layer and the station layer is realized through a downlink channel, and the connection between the station hall layer and the outdoor ground is realized through an entrance.

6. The underground excavated subway station of suspension type station hall layer and independent rail row area as claimed in claim 1, characterized in that: the middle position of the station hall A is connected to the station hall downlink channel A through the station hall downlink channel straight section, the station hall downlink channel A is obliquely arranged and is internally provided with a staircase, and the middle of the station hall downlink channel straight section is provided with an accessible elevator channel.

7. The underground excavated subway station of suspension type station hall layer and independent rail row area as claimed in claim 1, characterized in that: the middle position of the B station hall is connected to a B station hall downlink channel through a B station hall downlink channel straight section, and the B station hall downlink channel is obliquely arranged and is internally provided with a staircase.

8. A construction method for underground excavation of subway stations in a suspension type station hall layer and an independent rail traveling area is characterized by comprising the following steps:

the method comprises the following steps: constructing a vertical shaft from the air duct, drilling vertical shafts at the air ducts at two ends, and starting construction at the same time;

step two: constructing an air duct A and a station hall A from a temporary vertical shaft at the end A by adopting a CRD method, excavating by dividing into a plurality of blocks according to the height, wherein the length of a step excavated at each step is about 5-7m, erecting a grid steel frame and a temporary support after each step of excavation is finished, starting secondary lining in time after primary support is stable, excavating an air duct B from the temporary vertical shaft at the end B by adopting a step method, wherein the length of the step excavated at each step is 5-7m, and starting secondary lining in time after primary support is stable;

step three: constructing a C exchange channel by a step method, carrying out secondary lining by C45 concrete, and carrying out advanced pre-support and grouting for a large pipe shed and a small pipe to reinforce the stratum;

step four: constructing an exchange channel A by adopting a step method, carrying out permanent spray anchor support, constructing an exchange channel B by adopting the step method, and carrying out permanent spray anchor support;

step five: excavating an outlet and an inlet of the B end by adopting a method combining open excavation and underground excavation, and starting the construction and the laying of the station hall B from the outlet and the inlet of the B end;

step six: when the station B hall is excavated to the bottom elevation of the straight section of the downlink channel of the station B hall, the straight section of the downlink channel of the station B hall is constructed by a step method;

step seven: and after finishing secondary lining in the station hall, the air duct and the exchange channel and reaching the design strength, reversely constructing the downlink channel from bottom to top by adopting a CRD (cross section dimension) method or a step method according to the section dimension and the geological condition.

9. The construction method of the underground excavation subway station of the suspension type station hall layer and the independent rail traveling zone as claimed in claim 8, characterized in that: in the second step: after the construction and the support of the air ducts at the two ends are finished, simultaneously, respectively opening holes from the circuitous air duct of the air duct station layer at the A end, the safety control room and the ventilation and air conditioning electric control room of the air duct station layer at the B end to construct towards the middle by adopting a full-section method, excavating an upper-track-area tunnel, stopping construction at the B end when the distance between the tunnel faces at the two ends is 20m, and tunneling the A end to be through;

and simultaneously, respectively opening holes from the circuitous air duct of the air duct station layer at the A end, the safety control room and the ventilation and air conditioning electric control room of the air duct station layer at the B end, starting construction towards the middle by adopting a full section method, excavating a tunnel in a down-track area, stopping construction at the B end when the distance between the tunnel faces at the two ends is 20m, and tunneling and communicating the A end.

10. The construction method of the underground excavation subway station of the suspension type station hall layer and the independent rail traveling zone as claimed in claim 8, characterized in that: the fifth step comprises the following substeps:

step 5.1: the method comprises the following steps of (1) openly excavating an entrance from an entrance ground opening, wherein the length of the entrance of an openly excavated section is 2m, and the enclosure structure is constructed by adopting a smooth method in the form of a steel pipe pile, an anchor cable and a rib beam;

step 5.2, open excavation is carried out until the light and shade excavation junction is reached, and downward excavation meets the requirement of a pipe shed construction space; driving a self-advancing pipe shed into the arch part along the outer contour of the underground excavated section; plugging the tunnel face after entering the tunnel for 3-5 m;

step 5.3: then adopting a CD method or a CRD method to continuously excavate the foundation pit downwards to the substrate;

step 5.4: and excavating the B station hall by adopting a middle tunnel method from the B end entrance and exit base, advancing the large pipe shed and the small pipe to carry out pre-support by means of advanced grouting, and carrying out construction and laying of the B station hall by adopting a vertical slope retaining and longitudinal slab staggering construction method.

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