CN217462171U - Large-span cross-sectional undercut tunnel stagnant water reinforced structure - Google Patents
Large-span cross-sectional undercut tunnel stagnant water reinforced structure Download PDFInfo
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- CN217462171U CN217462171U CN202220296506.1U CN202220296506U CN217462171U CN 217462171 U CN217462171 U CN 217462171U CN 202220296506 U CN202220296506 U CN 202220296506U CN 217462171 U CN217462171 U CN 217462171U
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Abstract
The utility model provides a sectional undercut tunnel stagnant water reinforced structure of large-span. The underground excavation tunnel is divided into an upper-layer underground excavation tunnel constructed firstly and a lower-layer underground excavation tunnel constructed later, and the water stopping reinforcing structure comprises an advanced reinforcing layer, a pipe shed supporting structure and a contour line water stopping wall; the advanced reinforcing layer is an arc-shaped reinforcing structure formed by performing advanced grouting on the upper underground tunnel arch part stratum before tunnel excavation; the pipe shed supporting structure is arranged along the excavation contour line of the arch part of the upper-layer underground tunnel; the contour line water stop wall is a U-shaped water stop reinforcing structure formed by grouting along an inverted arch contour line deep hole of a lower-layer underground excavated tunnel from the bottom surface of the upper-layer underground excavated tunnel after the construction of the upper-layer underground excavated tunnel of each section of underground excavated tunnel is completed. The utility model discloses ensured that the undercut passageway can not cause the disturbance to it when threading pipe line and town road under, reduced the construction risk, solved the water gushing sand gushing condition that appears among the undercut tunnel process, also protected the water resource simultaneously.
Description
Technical Field
The utility model relates to a subway construction technical field relates to a receive stagnant water reinforced structure in large-span section undercut tunnel that groundwater influenced particularly.
Background
Along with the development of urban rail transit construction in China, more and more cities develop subway construction, and many subway construction ranges relate to overground or underground construction structures and comprise municipal roads or numerous municipal pipelines. In order to reduce the influence on municipal roads or pipelines, subway station channels are constructed in a mode of underground excavation and underpass. Meanwhile, with the requirement on underground water resource protection increasing, even the underground water mining is limited in partial areas, so that underground excavation channels affected by the underground water cannot be subjected to precipitation, but in consideration of the great influence of the underground water on underground excavation construction, a waterproof curtain is arranged to ensure that the tunnel excavation range is free of water operation.
In the concrete construction process, some special conditions are often encountered, for example, a section of a railway station transfer passage in Beijing is constructed by an undercut method, the ground layers involved in tunnel excavation mainly comprise a pebble layer and a silty clay layer, and the newly exposed stable water level of underground water is positioned at the temporary inverted arch of the undercut tunnel. According to the current traffic conditions of the road and the influence of the surrounding environment, the groundwater influencing the construction of the underground excavated tunnel cannot be subjected to precipitation treatment by combining the requirement of Beijing City on groundwater resource protection. Therefore, the water-stop walls are arranged along the excavation contour line of the underground excavation tunnel, and the water-stop walls arranged at intervals on the excavation face form a closed water-stop curtain, so that the connection between the excavation range of the underground excavation tunnel and the surrounding underground water is cut off, and the condition of the underwater operation of the underground excavation method is achieved. The waterproof curtain degree of difficulty of lower floor's cavern construction excavation contour line and face is great, and the operating space is comparatively narrow and small, and can destroy the integrality of the one stagnant water wall that has been under construction formation behind when the one stagnant water wall construction before on the face, then the risk that gushes water and gush sand can appear, and unforeseen factor in the work progress is more, and groundwater handles improper then can have bigger risk.
In addition, the underground excavation tunnel with the large-span section can cause the settlement deformation of pipelines and municipal roads in the excavation process, and the underground excavation channel cannot be disturbed when passing through the pipelines and the municipal roads in the construction process.
Disclosure of Invention
The utility model discloses according to the problem that prior art exists, a receive groundwater to influence stagnant water reinforced structure in large-span section undercut tunnel, this structure both can avoid the gushing water sand gushing condition that appears in the undercut tunnel construction, can solve the disturbance of undercut in-process to town road and major pipeline again, ensure that structure overall stability is reliable, reduce the construction risk.
In order to solve the problem, the utility model provides a sectional undercut tunnel stagnant water reinforced structure of large-span, its characterized in that: the underground tunnel is formed by segmented construction, each segment of underground tunnel is divided into an upper-layer underground tunnel constructed firstly and a lower-layer underground tunnel constructed later, and the water-stopping reinforcing structure comprises an advanced reinforcing layer positioned above an arch part of the upper-layer underground tunnel, a pipe shed supporting structure arranged along an excavation contour line of the arch part of the upper-layer underground tunnel and a contour line water-stopping wall positioned below an inverted arch of the lower-layer underground tunnel; the advanced reinforcing layer is an arc-shaped reinforcing structure formed by performing advanced grouting on the upper underground tunnel arch part stratum before tunnel excavation; the contour line waterstop wall is a U-shaped waterstop reinforcing structure formed by grouting an upper-layer underground excavated tunnel of each section of underground excavated tunnel along an inverted arch contour line deep hole of a lower-layer underground excavated tunnel from the bottom surface of the upper-layer underground excavated tunnel after the construction of the upper-layer underground excavated tunnel is completed, and the contour line waterstop wall and the advanced reinforcing layer are connected into a whole on the cross section to form a reinforcing structure which encloses the underground excavated tunnel.
The utility model discloses further technical scheme: the waterproof reinforced structure further comprises a face waterproof wall formed by deep hole grouting of the bottom surface of each section of the underground excavated tunnel after the construction of the upper layer of the underground excavated tunnel is completed, the bottom surface of the face waterproof wall and the contour line waterproof wall are connected into a whole to form a closed waterproof curtain, and the width of the face waterproof wall is 1.8-2.2 m.
The utility model discloses better technical scheme: the upper-layer underground tunnel and the lower-layer underground tunnel are formed by construction in a way that the upper-layer underground tunnel and the lower-layer underground tunnel are divided into three caverns, and each layer of underground tunnel is firstly constructed with a middle cavern and then constructed with two side caverns; the construction length of each section of the middle cavern is 10-15m, and the construction length of each section of the caverns on the two sides is 7-10 m; and a foot locking anchor pipe is arranged at the arch foot position of the upper-layer underground tunnel, the foot locking anchor pipe is 2-3 m long, and the horizontal inclination angle is 30 degrees.
The utility model discloses better technical scheme: the pipe shed supporting structure is formed by constructing the outer contour line of the excavation of the upper-layer underground tunnel within the range of 100-300 mm, and the circumferential distance of steel pipes of the pipe shed is 30-40 cm.
The utility model discloses better technical scheme: the width of the advanced reinforcing layer is 2-2.5 m, the grouting width of the contour line water stop wall is 3-3.5 m, and the horizontal length of each grouting is 6-8 m.
The utility model discloses better technical scheme: the steel pipe of the pipe shed supporting structure is a hot-rolled seamless steel pipe with the diameter phi of 159mm and the wall thickness of 6mm, the steel pipe joints are connected by screw threads, the length of the screw thread section is more than 6cm, when the pipe shed is constructed, two adjacent steel pipe joints are staggered in a different pipe joint combination mode, and the misconnection length is not less than 1.0 m; the steel pipe is externally provided with a pre-embedded pipe shed guide pipe, grouting holes in the steel pipe are arranged in a quincunx shape, the distance between the grouting holes is 12-18 cm, the hole diameter is 8-12 mm, and the grouting holes are not arranged in the range of 1.8-2.2 m away from the tail section of the orifice of the steel pipe.
The utility model discloses better technical scheme: the deep hole grouting pressure of the advanced reinforcement layer, the contour line water-stop wall and the tunnel face water-stop wall is controlled to be 0.5-0.8 MPa, and the grouting slurry adopts cement-water glass double-liquid slurry; the soil body after deep hole grouting meets the condition that the permeability coefficient is not more than 1.0 multiplied by 10 -6 cm/s and unconfined compressive strength of not less than 0.5 MPa.
The utility model discloses the advance support form of adopting "big pipe shed + deep hole slip casting" has carried out pre-consolidation to undercut tunnel hunch portion stratum before the construction to reduce the pipeline that tunnel excavation arouses and municipal road's the deformation that subsides, and stay core soil successive layer subsection excavation at each cavern, it is advanced to follow "pipe, tight slip casting, short excavation, strong support, measurement on duty, the principle of early sealing" has ensured that the undercut passageway can not cause the disturbance to it when wearing pipeline and municipal road down, ensure that the construction can normally go on, construction risk has been reduced. And in the construction process, an upper-layer cavern is constructed firstly, a waterproof curtain is constructed for a lower-layer cavern by utilizing the space of the upper-layer cavern, and the lower-layer cavern is excavated after pumping and draining residual underground water between stratums, so that the aim of guaranteeing the underwater operation of the underground excavation method under the condition of not lowering the water is fulfilled, the water and sand gushing condition in the process of underground excavation of the tunnel is solved, and meanwhile, the water resource is protected.
Drawings
Fig. 1 is a schematic cross-sectional structure of the present invention;
FIG. 2 is a schematic view of the structure of the vertical section of the present invention;
fig. 3 to 12 are schematic views of the construction process of the underground excavated tunnel according to the embodiment of the present invention;
fig. 13 is a connection diagram of the steel bar grating of the primary support structure in the embodiment.
In the figure: 1-pipe shed supporting structure, 2-advanced reinforcement layer, 3-contour line waterstop wall, 4-upper undercut tunnel, 5-lower floor undercut tunnel, 6-face waterstop wall, 7-upper undercut tunnel arch excavation contour line, 8-lock foot anchor pipe, 9-preliminary bracing structure, 10-middle bulkhead, 11-reserved core soil, 12-temporary inverted arch, 13-steel bar grating, 14-connecting plate, 15-middle bulkhead shaped steel, 16-secondary lining structure, 17-temporary steel support, 18-high strength bolt.
Detailed Description
The present invention will be further explained with reference to the drawings and examples. Fig. 1 to 13 are drawings of the embodiment, which are drawn in a simplified manner and are only used for clearly and concisely illustrating the purpose of the embodiment of the present invention. The following detailed description of the embodiments of the present invention is presented in the drawings and is not intended to limit the scope of the invention as claimed. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "inner", "outer", "left", "right", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, or orientations or positional relationships that are conventionally placed when the products of the present invention are used, or orientations or positional relationships that are conventionally understood by those skilled in the art, and are merely for convenience of description of the present invention and simplifying the description, but do not indicate or imply that the device or element that is referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
In the embodiment, the underground tunnel with the large-span section is formed by segmented construction, as shown in fig. 1 and fig. 2, each segment of the underground tunnel is divided into an upper-layer underground tunnel 4 constructed firstly and a lower-layer underground tunnel 5 constructed later, the upper-layer underground tunnel 4 and the lower-layer underground tunnel 5 are divided into three chambers for construction, each layer of the underground tunnel is constructed with a middle chamber firstly and then two side chambers are constructed; the construction length of each section of the middle cavern is 10-15m, and the construction length of each section of the caverns on the two sides is 7-10 m; DN32X2.75 foot-locking anchor pipes 8 are arranged at the arch feet of the upper-layer underground tunnel 4, the foot-locking anchor pipes 8 are 2-3 m long, and the horizontal inclination angle is 30 degrees.
In the embodiment, the water-stopping reinforced structure of the large-span section underground tunnel is provided, as shown in fig. 1 and fig. 2, and comprises an advanced reinforced layer 2 positioned above an arch part of an upper-layer underground tunnel 4, a pipe shed supporting structure 1 arranged along an excavation contour line 8 of the arch part of the upper-layer underground tunnel, a contour line water-stopping wall 3 positioned below an inverted arch of a lower-layer underground tunnel 5, and a tunnel face water-stopping wall 6 formed by grouting from a deep hole at the bottom surface of the upper-layer underground tunnel 4 after the construction of the upper-layer underground tunnel 4 of each section of underground tunnel is completed; the advanced reinforcing layer 2 is an arc-shaped reinforcing structure formed by performing advanced grouting on the arch part stratum of the upper-layer underground tunnel before tunnel excavation; contour line stagnant water wall 3 is after the construction of the upper undercut tunnel 4 in every section undercut tunnel is accomplished, along the U-shaped stagnant water reinforced structure of 5 inverted arch contour lines deep hole slip casting formation in lower floor undercut tunnel from the bottom surface in upper undercut tunnel 4, and contour line stagnant water wall 3 links as an organic whole on the cross-section with leading back up coat 2, forms a reinforced structure that will the undercut tunnel encloses to close. The bottom surface of the palm-side water-stopping wall 6 and the contour line water-stopping wall 3 are connected into a whole to form a closed water-stopping curtain, and the width of the palm-side water-stopping wall 6 is 1.8-2.2 m. The width of the advanced reinforcing layer 2 is 2-2.5 m, the grouting width of the contour line water stop wall 3 is 3-3.5 m, and the horizontal length of each grouting is 6-8 m. Pipe shed supporting construction 1 is that the outer profile line 100 ~ 300mm within range construction forms in the 4 excavation outer peripheral lines in upper undercut tunnels, and the steel pipe hoop interval of pipe shed is 30 ~ 40 cm.
In the embodiment, the deep hole grouting pressure of the advanced reinforcement layer 2, the contour line water stop wall 3 and the tunnel face water stop wall 6 is controlled to be 0.5-0.8 MPa, the grouting slurry adopts cement-water glass double-liquid slurry, and the water-cement ratio of the cement slurry is 0.8: 1-1: 1, wherein the volume ratio of the cement paste with the water glass concentration of 35 Be' to the water glass is 1: 1-1: 0.6, and the specific proportion is adjusted according to the specific geological condition during grouting; the soil body after deep hole grouting meets the condition that the permeability coefficient is not more than 1.0 multiplied by 10 -6 cm/s and unconfined compressive strength of not less than 0.5 MPa. The steel pipe of the pipe shed supporting structure 1 is a hot-rolled seamless steel pipe with the diameter phi of 159mm and the wall thickness of 6mm, the steel pipe joints are connected by screw threads, the length of the screw thread section is more than 6cm, when the pipe shed is constructed, two adjacent steel pipe joints are staggered in a different pipe joint combination mode, and the misconnection length is not less than 1.0 m; pipe construction error: the radial direction is not more than 20cm, and the direction along the adjacent steel pipe is not more than 10 cm; in order to accurately position the drill hole, a pipe shed guide pipe with the diameter of phi 219, the wall thickness of 5mm and the length of 1.5m is pre-embedded; and (3) drilling and grouting on the steel pipe, wherein the aperture phi is 10mm, the hole spacing is 15cm, the steel pipe is arranged in a quincunx manner, and holes which are not drilled are arranged at the tail part (orifice section) of the steel pipe at 2.0m and are used as a grout stopping section.
It is right to combine the embodiment below the utility model discloses concrete work progress and this stagnant water reinforced structure are in the application of undercut tunnel construction, and the embodiment specifically is the subway station transfer passageway construction project, and this subway station transfer passageway adopts open cut method + construction of undercut method, and open cut part is two-layer twin columns three-span concrete structure in the underground, and the undercut section is the preliminary bracing secondary lining combined type lining cutting structure, the U-shaped section. The length of the underground excavation section is 41.38m, the maximum span of the section is 13.9m, the height is 8.07m, and the depth of the soil covering is 12.38 m. The thickness of the primary supporting structure is 350mm, the thickness of the middle partition wall and the temporary inverted arch is 300mm, and the thickness of the secondary lining structure is 900 mm. The primary support structure is originally designed to be constructed by a double-side-wall pit guiding method, and the section of the primary support structure is divided into an upper layer and a lower layer, and six chambers are excavated. The tunnel is located in a pebble stratum and is provided with a powdery clay layer with the thickness of about 4m, the temporary inverted arch of the tunnel is located 0.2-0.3 m above the underground water level, and the construction of a lower-layer chamber is influenced by underground water.
The west half road of the municipal road is penetrated under the underground excavation section of the transfer passage, the whole width is a bidirectional 10 lane +2 non-motor lane, and the total width of the road is 80 m. Under the road exists
A medium-pressure gas pipeline,
A high-pressure gas pipeline,
A water feeding pipe,
The gas pipeline and the water supply pipeline are made of steel pipes, and the 2400 x 1200 rainwater square ditch is of a brick masonry structure and is about 8m away from the nearest distance of a tunnel vault. Transfer the north side of passageway and east side simultaneously and all be close to existing subway operation line, belong to one-level risk source, have great risk, need strengthen the protection in the work progress, in order to guarantee the security of tunnel construction, adopted the utility model discloses a stagnant water reinforced structure carries out the construction of undercut tunnel, and its specific work progress is as follows:
(1) determining a tunnel excavation contour line according to a design drawing, marking by adopting spray painting, constructing a large pipe shed 1 100mm outside an excavation contour line of a tunnel arch part as shown in figure 3, and then adopting a deep hole grouting process to perform advanced grouting reinforcement on an arch part stratum, wherein the reinforcement range is 1.5m outside the excavation contour line and 0.5m inside the contour line;
(2) accurately setting out to determine the excavation range of a cavern, reserving a cavern soil body in the middle of a subsurface tunnel 4 on the upper excavation layer of core soil of a cavern, erecting a steel arch frame, constructing a locking anchor pipe 8, and constructing a primary supporting structure 9, a middle partition wall 10 and a temporary inverted arch 12 as shown in fig. 4;
(3) when the excavation footage of the No. cavity in the step (2) reaches 10-15m, reserving core soil of a region close to the No. cavity to excavate a soil body of the No. cavity as shown in fig. 5, connecting a preliminary supporting structure 9 of the No. cavity and a reinforcement bar grating with a connecting plate 14 of a reinforcement bar grating 13 reserved in the No. cavity (the connecting structure is shown in fig. 13), and constructing a preliminary supporting structure of the No. cavity and a temporary inverted arch of the No. cavity;
(4) when the tunnel excavation footage of the No. 4 tunnel on the upper layer reaches 7-10m, temporarily closing the No. I tunnel face and the No. II tunnel face, and constructing contour line water-stopping walls 3 and the tunnel face water-stopping walls 6 excavated by the No. III tunnel and the No. II tunnel from the No. I tunnel and the No. II tunnel by adopting a deep hole grouting process as shown in FIG. 6 to form a closed water-stopping curtain;
(5) after the construction in the step (4) is completed, removing temporary supports faced by the tunnel faces of the first and second chambers, continuously reserving core soil to excavate soil bodies of the first and second chambers, synchronously reserving core soil to excavate soil bodies of the third chamber in the middle of the lower-layer underground tunnel 4, and constructing corresponding primary supports and middle partitions as shown in fig. 7;
(6) reserving core soil to excavate soil bodies of the No. four caverns at two sides of the lower-layer underground excavation tunnel 4 when the excavation footage of the No. three caverns in the step (5) reaches 10-15m, and applying primary support as shown in figure 8, wherein the large-section tunnel is integrally sealed into a ring;
(7) repeating the steps (1) to (6) until the construction of the primary support 3 is completed;
(8) as shown in fig. 9, the concrete of the middle bulkhead 1.5m above the secondary lining inverted arch of the tunnel part i of the tunnel 4 of the lower underground excavation is broken by sections, the profile steel 15 of the middle bulkhead is cut off in a manner of 'one-by-one removal', a secondary lining inverted arch structure is constructed, and backfilling is completed;
(9) as shown in fig. 10, the temporary inverted arch of the second grotto of the upper layer underground excavated tunnel is removed in sections, a secondary lining side wall structure is constructed, and temporary steel supports 17 are erected;
(10) as shown in fig. 11, the remaining temporary inverted arches 7 and the middle partition walls 4 are dismantled in sections, and a secondary lining dome structure is constructed;
(11) and (5) repeating the steps (8) to (10) until the secondary lining 10 is completely finished, and removing the temporary steel support 11 after the secondary lining is closed into a ring as shown in figure 12.
The construction time is calculated according to 12-hour construction, and the construction period is arranged as follows: the arch advanced support deep hole grouting time is 30 days, the lower-layer cavern waterproof curtain construction is carried out, the grouting width of an excavation contour line is 3m, the grouting width of a tunnel face is 2m, the grouting length is 6-8 m each time, and the construction time is 7 days. During grouting reinforcement, the surface uplift condition is closely concerned, and the surface settlement is controlled.
In the embodiment, when the excavation footage of the cavern reaches 10-15m, firstly, the soil body of the cavern is excavated according to the reserved core soil method instead of excavating the soil body of the cavern according to the conventional step sequence, the cavern is influenced by underground water and cannot be directly excavated, the cavern needs to be excavated firstly, and a working space is created for treating the underground water of the cavern at the lower layer III and the cavern at the fourth layer. And secondly, erecting a primary support steel bar grating after the excavation of the arch soil body of the tunnel chamber is finished, and connecting the primary support steel bar grating with a steel bar grating connecting plate reserved in the tunnel chamber, as shown in fig. 13, firstly adopting high-strength bolts for connection, adopting steel bars with the same diameter as the steel bars of the grating to perform side welding on main bars of the grating at two ends of the connecting plate, wherein the side welding length is not less than 10d, and the height of a welding line is not less than 8 mm. And (4) performing girth welding treatment on the grid connecting plate, wherein the height of a welding line is not less than 6mm, and timely performing primary support and temporary support after the grid connecting plate is inspected to be qualified.
In the embodiment, when the excavation depth of the No. 2 hole reaches 7-10m, HPB 3006 mm @150 x 150 steel bar net sheets are hung on the tunnel face of the No. 2 hole chamber and the tunnel face of the No. 2 hole chamber, inserting ribs are arranged at intervals of 500mm x 500mm, the steel bar type is HRB400E 20mm, the net sheets are connected with the inserting ribs in a spot welding mode, C20 premixed concrete is sprayed to temporarily close the tunnel face of the No. 2 hole chamber and the tunnel face of the No. 2 hole chamber, and a grout stop wall with the thickness of 6cm is formed. And then, applying waterproof curtains on excavation contour lines and tunnel faces of No. three and No. four chambers by adopting a deep hole grouting process, grouting according to a grouting angle determined by a scheme respectively by adopting a radial mode in the waterproof curtain construction within the excavation contour range, wherein the grouting angle and the number of grouting holes can be properly adjusted according to the grouting radius in the process, and grouting should be timely supplemented after excavation when grout fails to reach a place so as to ensure that the grouting range can cover a full section. The tunnel face water stop wall is directly connected with No. I and No. II caverns for vertical hole forming and grouting. Grouting at intervals, wherein grouting needs to be tested before formal grouting in each cycle, the grouting radius is determined to be within the range of the designed radius, and the grouting end standard is as follows: when the slurry suction amount is less than 1L/min, the slurry is continuously injected for 30min, and then the slurry injection is finished.
In the embodiment, in order to facilitate construction organization, the concrete of the secondary lining inverted arch structure is constructed firstly, and pouring is completed in two times, wherein the length of each section is about 20 m. In order to ensure the integral stability of the primary supporting structure, firstly, the concrete of the middle partition wall within the range of 1.5m above the inverted arch is broken, then the middle partition wall is cut in a mode of 'separating one from one' and removing one, the cutting height is 1m, after the reinforcement of the secondary lining inverted arch is finished, the cut middle partition wall is connected with the secondary lining reinforcement, and the middle partition wall is inserted into the concrete after the concrete of the inverted arch is poured. Ground settlement and tunnel deformation monitoring are enhanced in the process of temporary support concrete breaking and vertical support cutting, and if the temporary support concrete breaking and vertical support cutting are abnormal, the support is immediately recovered.
In the embodiment, the temporary support dismantling and the structure construction in the step (9) and the step (10) are performed alternately, the temporary inverted arch of the cavern is dismantled in sections, the length of each section is not more than 6m, then the side wall structure is constructed by adopting a shaping steel die, the temporary steel supports are erected in time, and the side wall structure is prevented from being extruded and deformed into the tunnel by the surrounding rock load. After the side wall structure reaches certain intensity, demolish the median septum and the horizontal brace of all remaining preliminary bracing structures, adopt the support system construction vault structure of full hall support + steel mould, whole secondary lining structure seals the cyclization, demolish interim supporting in-process and before the structure does not reach the design requirement, need strengthen ground subside and tunnel deformation monitoring, if unusual the removal of stopping immediately, resume interim supporting.
The above description is only an embodiment of the present invention, and the above-mentioned embodiment only expresses the present invention, and the description thereof is specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (7)
1. The utility model provides a sectional undercut tunnel stagnant water reinforced structure of large-span for the undercut tunnel of segmentation construction, every section undercut tunnel divide into the upper strata undercut tunnel (4) of constructing earlier and the lower floor undercut tunnel (5) of back construction, its characterized in that: the water-stopping reinforcing structure comprises an advanced reinforcing layer (2) positioned above an arch part of the upper-layer underground tunnel (4), a pipe shed supporting structure (1) arranged along an excavation contour line (7) of the arch part of the upper-layer underground tunnel, and a contour line water-stopping wall (3) positioned below an inverted arch of the lower-layer underground tunnel (5); the advanced reinforcing layer (2) is an arc-shaped reinforcing structure formed by performing advanced grouting on the arch part stratum of the upper-layer underground excavated tunnel; the contour line water stop wall (3) is a U-shaped water stop reinforcing structure formed by deep hole grouting along an inverted arch contour line of a lower-layer underground tunnel (5) from the bottom surface of the upper-layer underground tunnel (4), and the contour line water stop wall (3) and the advanced reinforcing layer (2) are connected into a whole on the cross section to form a reinforcing structure which surrounds the underground tunnel.
2. The underground excavation tunnel stagnant water reinforced structure of large-span section of claim 1, characterized in that: the waterproof reinforced structure is a tunnel face water-stopping wall (6) formed by deep hole grouting on the bottom surface of an upper-layer undercut tunnel (4), the bottom surface of the tunnel face water-stopping wall (6) and the contour line water-stopping wall (3) are connected into a whole to form a closed waterproof curtain, and the width of the tunnel face water-stopping wall (6) is 1.8-2.2 m.
3. The underground excavation tunnel water stop reinforcing structure of large-span section according to claim 1 or 2, characterized in that: the upper-layer underground excavation tunnel (4) and the lower-layer underground excavation tunnel (5) are formed by construction in three chambers, wherein the construction length of each section of the middle chamber is 10-15m, and the construction length of each section of the two side chambers is 7-10 m; and a foot locking anchor pipe (8) is arranged at the arch foot position of the upper-layer underground tunnel (4), the foot locking anchor pipe (8) is 2-3 m long, and the horizontal inclination angle is 30 degrees.
4. The underground excavation tunnel water stop reinforcing structure of large-span section according to claim 1 or 2, characterized in that: pipe shed supporting construction (1) is that the outer profile of excavation in upper undercut tunnel (4) 100 ~ 300mm within range construction forms, and the steel pipe hoop interval of pipe shed is 30 ~ 40 cm.
5. The underground excavation tunnel water stop reinforcing structure of large-span section according to claim 1 or 2, characterized in that: the width of the advanced reinforcing layer (2) is 2-2.5 m, the grouting width of the contour line water stop wall (3) is 3-3.5 m, and the horizontal length of each grouting is 6-8 m.
6. The underground excavation tunnel water stop reinforcing structure of large-span section according to claim 1 or 2, characterized in that: the steel pipe of the pipe shed supporting structure (1) is a hot-rolled seamless steel pipe with the diameter phi of 159mm and the wall thickness of 6mm, the steel pipe joints are connected by screw threads, the length of the screw thread section is more than 6cm, when the pipe shed is arranged, two adjacent steel pipe joints are staggered in a different pipe joint combination mode, and the misconnection length is not less than 1.0 m; the steel pipe is externally provided with a pre-embedded pipe shed guide pipe, grouting holes in the steel pipe are arranged in a quincunx shape, the distance between the grouting holes is 12-18 cm, the hole diameter is 8-12 mm, and the grouting holes are not formed in the steel pipe within a range of 1.8-2.2 m away from the tail section of the orifice.
7. The underground excavation tunnel stagnant water reinforced structure of large-span section of claim 2, characterized in that: the deep hole grouting pressure of the advanced reinforcement layer (2), the contour line water-stop wall (3) and the tunnel face water-stop wall (6) is controlled to be 0.5-0.8 MPa, and the grouting slurry adopts cement-water glass double-liquid slurry; the soil body after deep hole grouting meets the condition that the permeability coefficient is not more than 1.0 multiplied by 10 -6 cm/s, unconfined compressive strength of not less than0.5MPa。
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| CN202220296506.1U CN217462171U (en) | 2022-02-14 | 2022-02-14 | Large-span cross-sectional undercut tunnel stagnant water reinforced structure |
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| CN202220296506.1U CN217462171U (en) | 2022-02-14 | 2022-02-14 | Large-span cross-sectional undercut tunnel stagnant water reinforced structure |
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