CN109372558B - Construction method of underground excavation main body structure of subway super-large section tunnel - Google Patents
Construction method of underground excavation main body structure of subway super-large section tunnel Download PDFInfo
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- CN109372558B CN109372558B CN201811613136.4A CN201811613136A CN109372558B CN 109372558 B CN109372558 B CN 109372558B CN 201811613136 A CN201811613136 A CN 201811613136A CN 109372558 B CN109372558 B CN 109372558B
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- 238000010276 construction Methods 0.000 title claims abstract description 66
- 238000009412 basement excavation Methods 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 claims abstract description 42
- 238000005192 partition Methods 0.000 claims abstract description 16
- 229910001294 Reinforcing steel Inorganic materials 0.000 claims abstract description 8
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 151
- 239000010959 steel Substances 0.000 claims description 151
- 238000013461 design Methods 0.000 claims description 5
- 239000010426 asphalt Substances 0.000 claims description 4
- 239000011347 resin Substances 0.000 claims description 4
- 229920005989 resin Polymers 0.000 claims description 4
- 229920001038 ethylene copolymer Polymers 0.000 claims description 2
- 238000003466 welding Methods 0.000 claims 3
- 230000000694 effects Effects 0.000 description 5
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000009415 formwork Methods 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/38—Waterproofing; Heat insulating; Soundproofing; Electric insulating
- E21D11/383—Waterproofing; Heat insulating; Soundproofing; Electric insulating by applying waterproof flexible sheets; Means for fixing the sheets to the tunnel or cavity wall
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/14—Lining predominantly with metal
- E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
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Abstract
A construction method of a main underground excavation structure of a subway super-large section tunnel relates to a construction method. The invention aims to solve the problem of potential safety hazard in the existing method for removing the multi-channel temporary middle partition wall with the large section. After primary support excavation and back grouting are finished, pouring a concrete cushion layer, breaking fifth-layer middle partition wall concrete and reinforcing mesh sheets, paving a waterproof layer, then performing reinforcing steel bars, templates and concrete pouring, and constructing a bottom plate structure; removing the horizontal supports on the two sides of the fourth layer, laying a side wall waterproof layer, and constructing a side wall structure; removing the horizontal supports on the two sides of the third layer, laying a side wall waterproof layer, and constructing a side wall structure and a lower middle layer plate; removing the horizontal supports on the two sides of the second layer, laying a side wall waterproof layer, and constructing a side wall structure and an upper middle layer plate; removing horizontal supports on two sides of the first layer, replacing supports in the arch part vertical supports, laying side walls and arch part waterproof layers, and constructing side wall and arch part structures; and (4) removing all vertical supports. The invention is used in subway and tunnel engineering.
Description
Technical Field
The invention relates to a construction method, in particular to a construction method of a main underground excavation structure of a subway super-large section tunnel, and belongs to the related technical field of subway and tunnel engineering.
Background
In the urban subway construction process, an ultra-large section tunnel (the excavation span is 10m to 15m, and the ultra-large section means that the area of the excavated section is more than 100 square meters) such as a cross-over line, a return line, a field section entrance and exit line, a parking line, a connecting line, an air duct, a station and the like is inevitably encountered. When conditions such as ground traffic, buildings and the like permit, an open cut method is usually adopted to construct an ultra-large section tunnel, for example, the total length of a region between a Hanxi station and a bridge station in a Guangzhou subway No. 3 line is about 6km, a shield method is mainly adopted to construct the tunnel, but an open cut method is adopted for 1.3km, the tunnel comprises a parking line with the length of 260m, and meanwhile, a single crossover line, a track panel well, a communication channel, a pump room and the like are also arranged. However, subway engineering is mainly built in urban areas, open excavation is not allowed under ground conditions, and only a hidden excavation method can be adopted for construction, such as construction of a large-section tunnel between Chang-Ping-Dong-Guangting stations of Chang-Ping lines of Beijing rail transit, and a CRD construction method (a method for processing waterproof nodes of a partition wall in a large-section hidden excavation tunnel by a Huangliang ice CRD method, a municipal technology: 2016S 1).
Due to the complex urban environmental conditions, such as dense buildings, numerous underground pipelines, abundant soft soil strata and underground water, the underground super-large section tunnel is mainly excavated in a layered underground manner by adopting a double-side-wall pit guiding method, for example, the air duct underground excavation project of a government station in Haerbin No. 2 line province is that about 230 square meters (11 meters in span and 20 meters in height) of the excavation section is excavated, and 15 parts of 5 layers are excavated and supported. The ultra-large section soft soil tunnel is excavated by a double-side-wall pit guiding method in a layered and concealed mode, after excavation and supporting are completed, a construction waterproof layer and a main structure (secondary lining) relate to the problem of support replacement safety (Liu winter, a key construction technology for support removal and support replacement of subway tunnel cross line sections, 2017 Chinese architecture construction academic annual meeting statement (professional roll)), and if the scheme and measures adopted are not proper, primary support deformation is caused, accidents such as collapse are caused, and construction safety is seriously threatened.
At present, a patent about support replacement authorizes a large-section tunnel secondary lining construction support replacement process (invention 201210586406.3), the patent aims at a CRD method, I-shaped steel is adopted as an inclined support (supported on a steel plate pre-embedded in inverted arch backfill concrete) on one side of a vertical support for support replacement, and the inclined support of the method influences the construction operation space of side wall concrete. The patent also discloses a method for constructing a large-section tunnel by dismantling and replacing supports and a secondary lining (application number 201710588598.4), which is directed at a CRD (cross-linking detection) method, and directly cuts off an inverted arch in the construction of a lower middle bulkhead, then cuts off a temporary inverted arch construction side wall and finally cuts off an arch part in the construction of an upper middle bulkhead, wherein support replacing measures are not adopted, and potential safety hazards exist. A method (application number 201810026398.4) for removing a large-section multi-channel temporary middle partition wall adopts a mode of removing 2 partitions at intervals of 1 partition, firstly cuts off a section of the bottom, lays a waterproof layer, then puts a rubber backing plate and a supporting plate, and finally welds deformed steel bar supporting legs with I-shaped steel and the supporting plate respectively to reestablish a supporting function.
In conclusion, the double-side-wall pit guiding method adopted in the existing method for removing the large-section multi-channel temporary middle partition wall is used for removing the support in the waterproof layer of the underground excavated subway super-large-section tunnel with 5 layers and 15 steps and secondary lining construction, and the waterproof layer is laid after the support is cut off, so that the potential safety hazard problem exists.
Disclosure of Invention
The invention aims to solve the problem of potential safety hazard caused by laying a waterproof layer after cutting off a support in the conventional method for removing the large-section multi-channel temporary middle partition wall. Further provides a construction method of the underground excavation main body structure of the subway super-large section tunnel.
The technical scheme of the invention is as follows: a construction method of a subway super-large section tunnel underground excavation main body structure is characterized in that the subway super-large section tunnel underground excavation main body structure is constructed by a forward construction method, and the implementation process of the construction method is as follows:
the method comprises the following steps: after the primary support excavation and the back grouting are finished, pouring a concrete cushion;
adopting a layered and sectional excavation supporting method, excavating and supporting layer by layer from top to bottom, grouting after primary supporting and back supporting, and pouring a concrete cushion layer to form a foundation pit supporting structure;
step two: breaking concrete and reinforcing mesh sheets, and dismantling part of I-shaped steel for the first time;
the foundation pit supporting structure sequentially comprises a fifth layer, a fourth layer, a third layer, a second layer and a first layer from bottom to top;
breaking the concrete and the reinforcing mesh on the first layer of the middle partition wall, and sequentially exposing a plurality of I-shaped steel from left to right at equal intervals; the plurality of I-shaped steels are sequentially a first I-shaped steel, a second I-shaped steel, a third I-shaped steel, a fourth I-shaped steel, a fifth I-shaped steel, a sixth I-shaped steel, a seventh I-shaped steel, an eighth I-shaped steel, a ninth I-shaped steel, a tenth I-shaped steel, an eleventh I-shaped steel, a twelfth I-shaped steel, a thirteenth I-shaped steel, a fourteenth I-shaped steel, a fifteenth I-shaped steel and a sixteenth I-shaped steel from left to right; the first I-beam to the eighth I-beam are a first group of vertical supports, and the ninth I-beam to the sixteenth I-beam are a second group of vertical supports;
the middle parts of the first group of vertical supports and the second group of vertical supports are connected through horizontally arranged double-spliced channel steel, and 2I-beams at the bottom of each vertical support are disassembled every 4I-beams, namely, a fifth I-beam, a sixth I-beam, an eleventh I-beam and a twelfth I-beam are disassembled;
step three: laying a waterproof layer and replacing a support;
laying first waterproof layers with the width of 1.5m at the lower ends of the fifth and sixth dismantled I-beams and the eleventh and twelfth I-beams respectively, and then supporting by adopting first support-changing I-beams at the middle position of a double-spliced channel between the fifth and sixth dismantled I-beams and the middle position of a double-spliced channel between the eleventh and twelfth I-beams;
step four: dismantling part of the I-steel for the second time, and paving a waterproof layer and replacing a support;
connecting the upper parts of the sixth I-beam and the eleventh I-beam through a double-spliced channel steel, removing the vertical supporting bottoms of the eighth I-beam and the ninth I-beam, laying a second waterproof layer with the width of 2.0m at the bottom of the eighth I-beam and the ninth I-beam, and supporting the double-spliced channel steel between the eighth I-beam and the ninth I-beam through a second support-replacing I-beam in the vertical direction;
step five: thirdly, removing part of the I-shaped steel, and paving a waterproof layer and replacing a support;
sequentially removing 1 of the 4I-beams at intervals in the middle, namely the tenth I-beam, and overlapping a first waterproof layer and a second waterproof layer at the lower end of the tenth I-beam, wherein the overlapping length of the waterproof layers is 0.25 m;
then the first support-changing I-shaped steel is supported at the position, namely the first support-changing I-shaped steel is supported on the double-spliced channel steel below the tenth I-shaped steel;
removing and replacing the remaining 1I-steel, namely the seventh I-steel, and overlapping the first waterproof layer and the second waterproof layer below the seventh I-steel, wherein the overlapping length of the waterproof layers is 0.25 m;
at this moment, the waterproof layer laying of 4.5m in the longitudinal direction is finished, the next working cycle is continued forward according to the method from the second step to the fifth step, and the waterproof layer laying of 4.5m is finished;
step six: binding the bottom plate steel bars and assembling templates on the finished waterproof layer, and pouring concrete to finish the construction of the tunnel bottom plate structure;
step seven: removing the horizontal supports on the two sides of the second layer, laying a side wall waterproof layer, binding part of side wall steel bars below the horizontal support on the third layer, assembling a template and a bracket, and pouring concrete to finish the construction of the part of side wall structure;
step eight: removing the horizontal supports on the two sides of the third layer, laying a side wall waterproof layer, binding the steel bars of the partial side walls and the lower middle plate below the horizontal support of the fourth layer, assembling a template and a support, and pouring concrete to finish the construction of the partial side walls and the lower middle plate;
step nine: dismantling the horizontal supports at the two sides of the fourth layer, laying a side wall waterproof layer, binding the steel bars of the part of the side wall below the horizontal support of the fifth layer and the upper middle layer plate, assembling a template and a support, and pouring concrete to finish the construction of the part of the side wall and the upper middle layer plate;
step ten: laying an arch waterproof layer in the range of the III area in the fifth layer, wherein the width of the arch waterproof layer is still 1.5m and 2m alternately, and enough length is reserved on two sides until the arch waterproof layer is lapped with the laid fifth layer at the arch feet on the two sides;
step eleven: a row of third support-replacing I-beams are adopted between two rows of vertical middle partition walls in the fifth layer for support replacement, second steel plates are welded at two ends of the third support-replacing I-beams, a rubber plate and a lower flange plate of a fourth support-replacing I-beam with the longitudinal length of 4.5m are adopted between the second steel plate at the top of the third support-replacing I-beam and the arch waterproof layer for bolted connection, and a second steel plate at the bottom of the third support-replacing I-beam is connected with a first layer of horizontal support I-beam flange plate by bolts;
step twelve: dismantling the vertical supports on the two sides of the upper part of the fifth layer horizontal support and the horizontal supports on the two sides of the fifth layer, dismantling two supports from back to front each time, then paving waterproof layers in a region I and a region II, paving the waterproof layers at intervals with the width of 1.5m and 2m, and lapping the waterproof layers by 0.25m until the waterproof layers are lapped with the waterproof layers of arch feet on the two sides by 0.25m, and thus finishing the paving work of a waterproof layer of an arch part with the length of 4.5m in the longitudinal direction;
step thirteen: repeating the tenth step to the twelfth step, and then performing arch part support replacement and waterproof layer laying cycle work until finishing the arch part waterproof layer laying work with the length of 9m in the longitudinal direction;
fourteen steps: erecting a support, binding reinforcing steel bars, installing a template and pouring concrete to finish the construction of the arch part structure;
step fifteen: and after the concrete of the arch part structure reaches over 75% of the designed strength, removing all the rest supports within the range of 9m, and entering the next construction cycle of 9m until the construction of the whole tunnel is finished.
Compared with the prior art, the invention has the following effects:
1. the invention adopts the vertical support replacing method of removing 2 supports every 4 supports, and the two rows of vertical supports adopt the mode of firstly left and then right, thereby ensuring the integrity and the spatiality of the initial support stress in the replacing support process (the period comprises laying a waterproof layer) (two local supports are removed, and the two forces are shared to the front and the rear two supports), and controlling the deformation and the safety. Therefore, the safety problem caused by dismantling the support in the construction of the waterproof layer and the main structure of the multi-part underground excavated subway super-large section tunnel by adopting a double-side-wall pit guiding method is solved.
2. The invention firstly removes two supports, and then annularly lays an ECB waterproof board (ECB is ethylene copolymer modified asphalt resin which is produced by blending ethylene and vinyl acetate copolymer with asphalt resin through a high-pressure method and is a high-molecular-weight thermoplastic random polymer), the width is 1.5m and 2.0m at intervals, and the lapping width is 0.25 m. The circumferential integrity and the good overlapping effect of the waterproof plate are ensured, so that the waterproof effect is improved.
3. The vertical supports of the invention are always kept until the main structure of the whole ring tunnel is completely constructed, the concrete is removed until the design strength reaches more than 75%, meanwhile, the horizontal supports are removed layer by layer from bottom to top, and the undetached supports play a certain supporting role for the main structure formwork supports, thereby reducing the support erection height and improving the concrete pouring quality.
4. The fifth layer vertical support two rows of the tunnel are replaced by the middle one row, so that the assembling space of the arch structure template rack is increased, and the construction efficiency is improved.
Drawings
Figure 1 is a schematic view of a tunnel supporting structure.
Fig. 2 is a schematic structural view of the tunnel supporting structure 1 with concrete to be broken and a reinforcing mesh 8.
Fig. 3 is a schematic view of the dismantling and support changing structure of the two rows of vertical intermediate walls 7 in the fifth layer 2.
Fig. 4 is a schematic view of the underground excavation support replacement and the main structure dismantling and support replacement process of the super-large section tunnel.
Fig. 5 is a schematic structural view of the double-spliced channel steel C after being connected to the first steel plate 27.
Fig. 6 is a schematic view of a connection node of the double-spliced channel steel C and the first I-shaped steel 9.
Fig. 7 is a schematic diagram of a connection node of a first support-changing I-steel H and a second support-changing I-steel I with an I-steel on a double-spliced channel steel C and a waterproof layer.
Wherein × represents the severance.
Detailed Description
The first embodiment is as follows: the embodiment is described with reference to fig. 1 to 7, and the construction method of the underground excavation main body structure of the metro ultra-large cross-section tunnel of the embodiment adopts a forward construction method, and the implementation process is as follows:
the method comprises the following steps: after the primary support excavation and the back grouting are finished, pouring a concrete cushion;
adopting a layered and sectional excavation supporting method, excavating and supporting layer by layer from top to bottom, grouting after primary supporting and back supporting, and pouring a concrete cushion layer to form a foundation pit supporting structure 1;
step two: breaking the concrete and the reinforcing mesh 8, and dismantling part of I-shaped steel for the first time;
the foundation pit supporting structure 1 sequentially comprises a fifth layer 2, a fourth layer 3, a third layer 4, a second layer 5 and a first layer 6 from bottom to top;
breaking the concrete and the reinforcing mesh 8 on the first layer middle partition 7, and sequentially exposing a plurality of I-shaped steels at equal intervals from left to right; the plurality of I-beams are sequentially a first I-beam 9, a second I-beam 10, a third I-beam 11, a fourth I-beam 12, a fifth I-beam 13, a sixth I-beam 14, a seventh I-beam 15, an eighth I-beam 16, a ninth I-beam 17, a tenth I-beam 18, an eleventh I-beam 19, a twelfth I-beam 20, a thirteenth I-beam 21, a fourteenth I-beam 22, a fifteenth I-beam 23 and a sixteenth I-beam 24 from left to right; the first I-beam 9 to the eighth I-beam 16 are a first group of vertical supports, and the ninth I-beam 17 to the sixteenth I-beam 24 are a second group of vertical supports;
the middle parts of the first group of vertical supports and the second group of vertical supports are connected through a horizontally arranged double-spliced channel steel C, 2I-beams at the bottom of each vertical support are disassembled every 4I-beams, namely a fifth I-beam 13, a sixth I-beam 14, an eleventh I-beam 19 and a twelfth I-beam 20 are disassembled;
step three: laying a waterproof layer and replacing a support;
laying a first waterproof layer 25 with the width of 1.5m at the lower ends of the fifth and sixth dismantled I- beams 13 and 14 and the eleventh and twelfth I- beams 19 and 20 respectively, and then supporting by using first support-changing I-beams H at the middle position of a double-spliced channel C between the fifth and sixth dismantled I- beams 13 and 14 and the middle position of a double-spliced channel C between the eleventh and twelfth I- beams 19 and 20;
step four: dismantling part of the I-steel for the second time, and paving a waterproof layer and replacing a support;
connecting the upper parts of the sixth I-beam 14 to the eleventh I-beam 19 through a double-spliced channel steel C, removing the vertical supporting bottoms of the eighth I-beam 16 and the ninth I-beam 17, laying a second waterproof layer 26 with the width of 2.0m at the bottom of the eighth I-beam 16 and the ninth I-beam 17, and supporting the double-spliced channel steel C between the eighth I-beam 16 and the ninth I-beam 17 through a second support-changing I-beam I in the vertical direction;
step five: thirdly, removing part of the I-shaped steel, and paving a waterproof layer and replacing a support;
sequentially removing 1 of the 4I-beams at intervals in the middle, namely the tenth I-beam 18, and overlapping a first waterproof layer 25 and a second waterproof layer 26 at the lower end of the tenth I-beam 18, wherein the overlapping length of the waterproof layers is 0.25 m;
then the first support-changing I-shaped steel H is supported at the position, namely the first support-changing I-shaped steel H is supported on the double-spliced channel steel C below the tenth I-shaped steel 18;
removing and replacing the remaining 1I-beam, namely the seventh I-beam 15 according to the method, and overlapping the first waterproof layer 25 and the second waterproof layer 26 below the seventh I-beam 15, wherein the overlapping length of the waterproof layers is 0.25 m;
at this moment, the waterproof layer laying of 4.5m in the longitudinal direction is finished, the next working cycle is continued forward according to the method from the second step to the fifth step, and the waterproof layer laying of 4.5m is finished;
step six: binding the bottom plate steel bars and assembling templates on the finished waterproof layer, and pouring concrete to finish the construction of the tunnel bottom plate structure;
step seven: removing the horizontal supports at the two sides of the second layer 5, laying a side wall waterproof layer, binding part of side wall steel bars below the horizontal support of the third layer 4, assembling templates and a bracket, and pouring concrete to finish the construction of the part of side wall structure;
step eight: removing the horizontal supports on the two sides of the third layer 4, laying a side wall waterproof layer, binding the steel bars of the partial side walls and the lower middle plate below the horizontal support of the fourth layer 3, assembling a template and a support, and pouring concrete to finish the construction of the partial side walls and the lower middle plate;
step nine: removing the horizontal supports at the two sides of the fourth layer 3, laying a side wall waterproof layer, binding the steel bars of the part of the side wall below the horizontal support of the fifth layer 2 and the upper middle layer plate, assembling a template and a support, and pouring concrete to finish the construction of the part of the side wall and the upper middle layer plate;
step ten: laying the arch waterproof layers in the range of the III area in the fifth layer 2, wherein the width of the arch waterproof layers is still 1.5m and 2m alternately, and enough length needs to be reserved on two sides until the arch waterproof layers are lapped with the laid fifth waterproof layers on the arch feet on the two sides;
step eleven, a row of third support-changing I-beams L are adopted between two rows of vertical middle partition walls 7 in the fifth layer 2 for support changing, second steel plates G are welded at two ends of a third support-changing I-beam L, a rubber plate F and a lower flange plate bolt of a fourth support-changing I-beam M with the longitudinal length of 4.5M are adopted between the second steel plate G at the top of the third support-changing I-beam L and the arch waterproof layer, and the second steel plate G at the bottom of the third support-changing I-beam L is connected with the flange plate of the first layer of horizontal support I-beam through bolts;
step twelve: dismantling the vertical supports at two sides of the upper part of the horizontal support of the fifth layer 2 and the horizontal supports at two sides of the fifth layer 2, dismantling two frames from back to front each time, then paving waterproof layers in an I area and an II area, paving the waterproof layers at intervals of 1.5m and 2m in width, and lapping the waterproof layers by 0.25m until the waterproof layers are lapped with the waterproof layers of arch feet at two sides by 0.25m, and thus finishing the paving work of a waterproof layer of an arch part with the length of 4.5m in the longitudinal direction;
step thirteen: repeating the tenth step to the twelfth step, and then performing arch part support replacement and waterproof layer laying cycle work until finishing the arch part waterproof layer laying work with the length of 9m in the longitudinal direction;
fourteen steps: erecting a support, binding reinforcing steel bars, installing a template and pouring concrete to finish the construction of the arch part structure;
step fifteen: and after the concrete of the arch part structure reaches over 75% of the designed strength, removing all the rest supports within the range of 9m, and entering the next construction cycle of 9m until the construction of the whole tunnel is finished.
The second embodiment is as follows: referring to fig. 1, the excavation supporting procedure in the first step of the present embodiment is as follows: and excavating and supporting in layers from top to bottom, wherein the two sides of the same layer are firstly excavated and then the middle of the same layer is excavated, and all the excavation and supporting work is finished. By the arrangement, the excavation and supporting efficiency is improved, the safety is ensured, and other components and connection relations are the same as those of the first embodiment.
The third concrete implementation mode: referring to fig. 2, the distance between two adjacent i-beams exposed on the first to fifth intermediate bulkheads 7 in the present embodiment is 0.5 m. So set up, the interval is reasonable, is convenient for guarantee the security performance of strutting. Other components and connection relationships are the same as those in the first or second embodiment.
The fourth concrete implementation mode: referring to fig. 5, the present embodiment is described, two ends of the double-spliced channel C in the length direction of the present embodiment are welded by using the first steel plates 27 having a thickness of 8mm, and the lap joint between the web C-1 of the double-spliced channel C and the flange plate of the i-beam described in the second step is bolted by using 4-hole bolts. So set up, firm in connection is reliable. Other components and connection relationships are the same as those in the first, second or third embodiment.
The fifth concrete implementation mode: the embodiment is described with reference to fig. 7, both ends in the length direction of the first support changing I-steel H and the second support changing I-steel I of the embodiment are welded by using second steel plates G with the thickness of 8mm, the tops of the first support changing I-steel H and the second support changing I-steel I are bolted with the channel steel flange plate of the double-spliced channel steel C in the second step to the fifth step by using 4-hole bolts, and the bottoms of the first support changing I-steel H and the second support changing I-steel I are installed on the rubber plate F. With the arrangement, the support replacing structure is firmer, and the waterproof board is prevented from being damaged. Other components and connections are the same as those of the first, second, third or fourth embodiments.
The sixth specific implementation mode: the present embodiment will be described with reference to fig. 1 to 7, and the next step can be performed when the curing strength reaches 75% or more of the design value after each concrete pouring of the present embodiment. So set up, vertical braces remains throughout, executes to do the completion until whole ring tunnel major structure, and the concrete reaches more than 75% of design intensity and just demolishs, and the horizontal braces is followed and is demolishd one deck ground upwards down simultaneously, does not demolish the support and play certain supporting role to major structure formwork support, has reduced the support and has set up the height to the quality of pouring of concrete has been improved. Other components and connection relationships are the same as those in the first, second, third, fourth or fifth embodiment.
The seventh embodiment: referring to fig. 7, the rubber plates F at the bottoms of the first support-replacing I-beam H and the second support-replacing I-beam I of the present embodiment are mounted on the waterproof layer. So set up, be convenient for protect the waterproof layer not receive the damage, support the effect that in-process rubber slab F can play the elastic adjustment moreover. Other components and connection relationships are the same as those in the first, second, third, fourth, fifth or sixth embodiment.
The specific implementation mode is eight: the present embodiment will be described with reference to fig. 7, and the rubber sheet F of the present embodiment has a length and width of 30cm and a thickness of 2 cm. With such an arrangement, the actual supporting requirements can be conveniently met, and other components and connection relations are the same as those of the first, second, third, fourth, fifth, sixth or seventh specific embodiment.
The specific implementation method nine: the present embodiment will be described with reference to fig. 7, and the rubber sheet F of the present embodiment is made of an ethylene copolymer-modified asphalt resin. With such an arrangement, the waterproof effect is good, and other components and connection relations are the same as those of the first, second, third, fourth, fifth, sixth, seventh or eighth embodiment.
Example 1:
(1) firstly, a layered and subsection excavation supporting method (as shown in figure 1) is adopted, excavation supporting is conducted from top to bottom in a layered mode, all excavation and supporting work is completed on the same layer firstly from two sides to the middle, grouting is conducted after primary support and back support are conducted, and a concrete cushion layer is poured.
(2) Then, the concrete and the steel mesh of the middle partition wall of the first layer are broken, 6I-beams (the distance is 0.5m) at the front and the back of each 2I-beams to be removed are longitudinally connected by adopting a double-spliced channel steel C, and then 2I-beams at the bottom of the vertical support are removed every 4I-beams, as shown in figure 4 a.
(3) And (3) paving a waterproof layer, wherein the width of the waterproof layer is 1.5m, and then replacing a support by using a new I-steel H among the 2 dismantled I-steels A, as shown in figure 4 b.
(4) And (5) continuing the support changing operation, connecting 6I-beams as shown in the middle C of the figure 4b, removing 2I-beams among the 4I-beams at intervals in the middle, paving a waterproof layer with the width of 2.0m, and changing the support by adopting the I-beam I in the figure 4C.
(5) And then sequentially removing 1 of the 4I-beams at intervals in the middle, overlapping the waterproof layer for 0.25m as shown in figure 4c, supporting at the position by using the I-beam H (as shown in figure 4d), removing the I-beam back support, and sequentially removing and replacing the remaining 1I-beam as shown in figures 4d and 4 e.
(6) And finishing the laying of the waterproof layer with the longitudinal length of 4.5m, continuing to perform a working cycle forward according to the method, and finishing the laying of the waterproof layer with the longitudinal length of 4.5 m.
(7) It should be noted that the beam ends of the double-spliced channel steel are welded by steel plates (25cm by 25cm) with the thickness of 8mm, and the lap joint of the web plate and the flange plate of the I-steel is bolted by 4-hole bolts (with the diameter of 28 mm). The two ends of H-beam and I-beam were also welded with 8mm thick steel plates (25cm x 25cm), the top was bolted with 4-hole bolts (diameter 28mm) to the channel flange plate, and the bottom was welded with 8mm thick steel plate G (25cm x 25cm) placed on rubber plate F (size 30cm x 30cm, thickness 2cm, placed on waterproof layer) as shown in fig. 7.
(8) And (4) binding the reinforcing steel bars of the bottom plate, assembling the templates, pouring concrete, finishing the construction of the tunnel bottom plate structure (the longitudinal length is 9m), and reserving reinforcing steel bar heads (the positions of side walls and the like).
(9) And (4) removing the horizontal supports on the two sides of the second layer, laying a side wall waterproof layer, binding the side wall steel bars below the horizontal support of the third layer, assembling a template, supporting the template, pouring concrete, and finishing the construction of the side wall structure.
(10) And (3) dismantling the horizontal supports at the two sides of the third layer, laying a side wall waterproof layer, binding the steel bars of the partial side walls and the lower middle plate below the horizontal support of the fourth layer, assembling the template, supporting the template, and pouring concrete to finish the construction of the partial side walls and the lower middle plate.
(11) And (4) dismantling the horizontal supports at the two sides of the fourth layer, laying a side wall waterproof layer, binding the steel bars of the part of the side wall below the horizontal support of the fifth layer and the upper and middle layer plates, assembling the template, supporting the template, and pouring concrete to finish the construction of the part of the side wall and the upper and middle layer plate structure.
(12) Laying the arch waterproof layers within the range of the III area, wherein the width of the arch waterproof layers is still 1.5m and 2m, and enough length is reserved on two sides until the arch waterproof layers are lapped with the laid waterproof layers at the arch feet on the two sides.
(13) A new row of I-steel L is replaced between two rows of vertical I-steel, steel plates G are welded at two ends of the new row of I-steel, the top steel plate is connected with a lower flange plate of the I-steel M with the longitudinal length of 4.5M through bolts, the bottom steel plate is connected with a flange plate of the fifth layer of horizontal supporting I-steel through bolts, as shown in figure 3, the bolts are all 4-hole bolts with the diameter of 28mm, and the longitudinal distance of the I-steel L is 1.5M.
(14) And (3) dismantling the vertical supports at two sides of the upper part of the horizontal support of the fifth layer and the horizontal supports at two sides of the fifth layer, dismantling two supports from back to front each time, then paving waterproof layers in a region I and a region II at intervals of 1.5m and 2m in width, and lapping for 0.25m until the width is lapped with the waterproof layers of the arch feet at two sides by 0.25 m.
(15) And finishing the laying work of the waterproof layer of the arch part with the length of 4.5m in the longitudinal direction, and then performing the cyclic work of arch part support replacement and waterproof layer laying until finishing the laying work of the waterproof layer of the arch part with the length of 9m in the longitudinal direction.
(16) And erecting a support, binding reinforcing steel bars, installing a template and pouring concrete to finish the construction of the arch part structure.
(17) After concrete pouring is completed, curing is required, and the next step can be performed until the strength reaches 75% or more of the design value.
(18) And after the concrete of the arch part structure reaches over 75% of the designed strength, removing all the rest supports within the range of 9m, and entering the next construction cycle of 9m until the construction of the whole tunnel is finished.
Claims (9)
1. A construction method of a main underground excavation structure of a subway super-large section tunnel is characterized by comprising the following steps: subway super large section tunnel undercut major structure adopts the construction of following the way, and its implementation process is:
the method comprises the following steps: after the primary support excavation and the back grouting are finished, pouring a concrete cushion;
adopting a layered and sectional excavation supporting method, excavating and supporting layer by layer from top to bottom, grouting after primary supporting and back pouring, and pouring a concrete cushion layer to form a foundation pit supporting structure (1);
step two: breaking the concrete and the reinforcing mesh (8), and dismantling part of I-shaped steel for the first time;
the foundation pit supporting structure (1) is sequentially provided with a fifth layer (2), a fourth layer (3), a third layer (4), a second layer (5) and a first layer (6) from bottom to top;
breaking concrete and reinforcing mesh sheets (8) on the first layer of middle partition wall (7), and sequentially exposing a plurality of I-shaped steel sheets at equal intervals from left to right; the plurality of I-shaped steels are sequentially a first I-shaped steel (9), a second I-shaped steel (10), a third I-shaped steel (11), a fourth I-shaped steel (12), a fifth I-shaped steel (13), a sixth I-shaped steel (14), a seventh I-shaped steel (15), an eighth I-shaped steel (16), a ninth I-shaped steel (17), a tenth I-shaped steel (18), an eleventh I-shaped steel (19), a twelfth I-shaped steel (20), a thirteenth I-shaped steel (21), a fourteenth I-shaped steel (22), a fifteenth I-shaped steel (23) and a sixteenth I-shaped steel (24) from left to right; the first I-beam (9) to the eighth I-beam (16) are a first group of vertical supports, and the ninth I-beam (17) to the sixteenth I-beam (24) are a second group of vertical supports;
the middle parts of the first group of vertical supports and the second group of vertical supports are connected through horizontally arranged double-spliced channel steel (C), 2I-beams at the bottom of the vertical supports are disassembled every 4I-beams, namely a fifth I-beam (13), a sixth I-beam (14), an eleventh I-beam (19) and a twelfth I-beam (20) are disassembled;
step three: laying a waterproof layer and replacing a support;
paving a first waterproof layer (25) with the width of 1.5m at the lower ends of the fifth and sixth dismantled I-beams (13) and (14) and the eleventh and twelfth I-beams (20), and then supporting the middle position of a double-spliced channel steel (C) between the fifth and sixth dismantled I-beams (13) and (14) and the middle position of a double-spliced channel steel (C) between the eleventh and twelfth I-beams (19) and (20) by adopting a first support-changing I-beam (H);
step four: dismantling part of the I-steel for the second time, and paving a waterproof layer and replacing a support;
connecting the upper parts of a sixth I-beam (14) and an eleventh I-beam (19) through a double-spliced channel steel (C), dismantling the vertical supporting bottoms of an eighth I-beam (16) and a ninth I-beam (17), laying a second waterproof layer (26) with the width of 2.0m at the bottom of the dismantled eighth I-beam (16) and the dismantled ninth I-beam (17), and supporting the double-spliced channel steel (C) between the eighth I-beam (16) and the ninth I-beam (17) through a second support-replacing I-beam (I) in the vertical direction;
step five: thirdly, removing part of the I-shaped steel, and paving a waterproof layer and replacing a support;
sequentially removing 1 of the 4I-beams at intervals in the middle, namely the tenth I-beam (18), and overlapping a first waterproof layer (25) and a second waterproof layer (26) at the lower end of the tenth I-beam (18), wherein the overlapping length of the waterproof layers is 0.25 m;
then the first support changing I-shaped steel (H) is supported at the root position, namely the first support changing I-shaped steel (H) is supported on a double-spliced channel steel (C) below a tenth I-shaped steel (18);
removing and replacing the remaining 1I-beam, namely the seventh I-beam (15), and overlapping the first waterproof layer (25) and the second waterproof layer (26) below the seventh I-beam (15), wherein the overlapping length of the waterproof layers is 0.25 m;
at this moment, the waterproof layer laying of 4.5m in the longitudinal direction is finished, the next working cycle is continued forward according to the method from the second step to the fifth step, and the waterproof layer laying of 4.5m is finished;
step six: binding the bottom plate steel bars and assembling templates on the finished waterproof layer, and pouring concrete to finish the construction of the tunnel bottom plate structure;
step seven: removing the horizontal supports on the two sides of the second layer (5), laying a side wall waterproof layer, binding the side wall reinforcing steel bars and assembling templates below the horizontal supports of the third layer (4), and pouring concrete to finish the construction of the side wall structure;
step eight: removing the horizontal supports on the two sides of the third layer (4), laying a side wall waterproof layer, binding the steel bars of the part of the side wall and the lower middle plate below the horizontal support of the fourth layer (3), assembling a template and a support, and pouring concrete to finish the construction of the part of the side wall and the lower middle plate;
step nine: removing the horizontal supports on the two sides of the fourth layer (3), laying a side wall waterproof layer, binding the steel bars of the part of the side wall below the horizontal support of the fifth layer (2) and the upper middle layer plate, assembling a template and a support, and pouring concrete to finish the construction of the part of the side wall and the upper middle layer plate;
step ten: the waterproof layer in the fifth layer (2) is laid in three areas, wherein the middle of each area is an area III, the left side of each area is an area I, and the right side of each area is an area II; laying an arch waterproof layer in the range of a III area in the fifth layer (2), laying the arch waterproof layers at intervals with the width of 1.5m and 2m, reserving enough length on two sides until the arch waterproof layers are lapped with the laid fifth layer at arch feet on the two sides;
eleven, replacing supports between two rows of vertical middle partition walls (7) in the fifth layer (2) by adopting a row of third support replacing I-beams (L), welding second steel plates (G) at two ends of the third support replacing I-beams (L), connecting the second steel plate (G) at the top of the third support replacing I-beam (L) with the arch waterproof layer by adopting a rubber plate (F) and a lower flange plate bolt of a fourth support replacing I-beam (M) with the longitudinal length of 4.5M, and connecting the second steel plate (G) at the bottom of the third support replacing I-beam (L) with the first layer of horizontal support I-beam flange plate by adopting a bolt;
step twelve: dismantling the vertical supports at two sides of the upper part of the horizontal support of the fifth layer (2) and the horizontal supports at two sides of the fifth layer (2), dismantling two roof trusses from back to front each time, then paving waterproof layers of a region I and a region II, paving the waterproof layers at intervals of 1.5m and 2m in width, and lapping the waterproof layers by 0.25m until the waterproof layers are lapped with the waterproof layers of arch feet at two sides by 0.25m, and finishing the paving work of the waterproof layers of the arch part with the length of 4.5m in the longitudinal direction;
step thirteen: repeating the tenth step to the twelfth step, and then performing arch part support replacement and waterproof layer laying cycle work until finishing the arch part waterproof layer laying work with the length of 9m in the longitudinal direction;
fourteen steps: erecting a support, binding reinforcing steel bars, installing a template and pouring concrete to finish the construction of the arch part structure;
step fifteen: and after the concrete of the arch part structure reaches over 75% of the designed strength, removing all the rest supports within the range of 9m, and entering the next construction cycle of 9m until the construction of the whole tunnel is finished.
2. The construction method of the underground excavation main body structure of the subway super-large section tunnel according to claim 1, characterized by comprising the following steps: the excavation supporting sequence in the first step is as follows: and excavating and supporting in layers from top to bottom, wherein the two sides of the same layer are firstly arranged in the middle, all excavating and supporting work is completed, and the distance between every two pilot tunnels is 3-5 m.
3. The construction method of the underground excavation main body structure of the subway super-large section tunnel according to claim 2, characterized by comprising the following steps: the distance between two adjacent I-shaped steels exposed on the first layer to the fifth layer middle partition (7) is 0.5 m.
4. The construction method of the underground excavation main body structure of the subway super-large section tunnel according to claim 1, characterized by comprising the following steps: and (3) welding two ends of the double-spliced channel steel (C) in the length direction by adopting first steel plates (27) with the thickness of 8mm, and bolting the web plate (C-1) of the double-spliced channel steel (C) and the flange plate lap joint of the I-shaped steel in the second step by adopting 4-hole bolts.
5. The construction method of the underground excavation main body structure of the subway super-large section tunnel according to claim 4, wherein: the first length direction both ends of trading and propping I-steel (H) and second and trade the second steel sheet (G) welding that props I-steel (I) that all adopt thickness to be 8mm, first trade prop I-steel (H) and second trade prop the top of I-steel (I) and step two to step five the channel-section steel flange plate of double-pin channel-section steel (C) adopt 4 hole bolt-ups, first trade prop I-steel (H) and second trade and prop the bottom of I-steel (I) and install on rubber slab (F).
6. The construction method of the underground excavation main body structure of the subway super-large section tunnel according to claim 1, characterized by comprising the following steps: after concrete pouring is finished each time, the next procedure can be carried out when the curing strength reaches over 75 percent of the design value.
7. The construction method of the underground excavation main body structure of the subway super-large section tunnel according to claim 5, wherein: the rubber plates (F) at the bottoms of the first support-changing I-shaped steel (H) and the second support-changing I-shaped steel (I) are arranged on the waterproof layer.
8. The construction method of the underground excavation main body structure of the subway super-large section tunnel according to claim 7, wherein: the length and width of the rubber sheet (F) were both 30cm, and the thickness was 2 cm.
9. The construction method of the underground excavation main body structure of the subway super-large section tunnel according to claim 8, wherein: the rubber plate (F) is made of ethylene copolymer modified asphalt resin.
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