CN116607975A - Three-step construction arch changing method for primary support intrusion limit part of shallow tunnel - Google Patents

Three-step construction arch changing method for primary support intrusion limit part of shallow tunnel Download PDF

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Publication number
CN116607975A
CN116607975A CN202310650053.7A CN202310650053A CN116607975A CN 116607975 A CN116607975 A CN 116607975A CN 202310650053 A CN202310650053 A CN 202310650053A CN 116607975 A CN116607975 A CN 116607975A
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CN
China
Prior art keywords
arch
construction
primary support
steel
tunnel
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Pending
Application number
CN202310650053.7A
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Chinese (zh)
Inventor
宋源
蒙国往
曾小林
梁昌愉
刘家乐
邓斌
梁陆佳
陈际全
磨伟
龙文亮
覃杰然
赵仁金
刘坤强
黄智明
陈信标
伍荣池
宋李泉
李泓霆
梁峻源
戚倪
韦耀文
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Guangxi Navigation Construction Engineering Co ltd
Guangxi University
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Guangxi Navigation Construction Engineering Co ltd
Guangxi University
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Application filed by Guangxi Navigation Construction Engineering Co ltd, Guangxi University filed Critical Guangxi Navigation Construction Engineering Co ltd
Priority to CN202310650053.7A priority Critical patent/CN116607975A/en
Publication of CN116607975A publication Critical patent/CN116607975A/en
Pending legal-status Critical Current

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Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/14Lining predominantly with metal
    • E21D11/18Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/04Lining with building materials
    • E21D11/10Lining 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
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/14Lining predominantly with metal
    • E21D11/18Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
    • E21D11/183Supporting means for arch members, not provided for in E21D11/22
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/38Waterproofing; Heat insulating; Soundproofing; Electric insulating
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/20Hydro energy

Abstract

The invention discloses a three-step construction arch changing method for a primary support intrusion position of a shallow tunnel, which comprises the following steps: (1) preparation for construction; (2) surface treatment; (3) back pressure backfilling in the hole; (4) temporary arch sleeving construction; (5) construction of an advanced greenhouse; (6) infringement primary support removal; (7) primary support construction of the upper step; (8) temporary inverted arch support construction; performing primary support construction on the middle-lower step; (10) inverted arch and filling layer construction; (11) removing the temporary support; (12) Repeating the steps (6) to (11), and sequentially carrying out arch changing construction on the limited primary support from the front and back directions of the tunnel arch changing section until the whole tunnel arch changing section finishes arch changing work; when the arch changing construction of the whole tunnel arch changing section is completed, the temporary sleeve arch can be removed; (13) performing double lining construction. The arch changing method can be used for changing the arch specifically for karst areas, has the advantages of small disturbance, high efficiency and stable support, and ensures construction safety.

Description

Three-step construction arch changing method for primary support intrusion limit part of shallow tunnel
Technical Field
The invention relates to the technical field of tunnel engineering construction, in particular to a three-step construction arch changing method for a primary support limit position of a shallow tunnel.
Background
The V-level surrounding rock mainly comprises carbonate rock, and erodes crack development, and water is discharged in a gushing or rain shape. Due to the development of the erosion cracks and karst cave, the rock mass is broken, and the self stability of surrounding rock is poor. During continuous heavy rain, a large amount of rainwater flows to the vicinity of the tunnel body along the water-removing hole and the corrosion cracks, and mud and water bursting phenomena easily occur during tunnel excavation.
The shallow underground tunnel is subjected to continuous rainfall, so that the water quantity in the arch crown cover layer gradually tends to be saturated, the self weight of the upper cover layer is increased, and the steel arch cannot bear the heavy weight, so that the steel arch is sunk. Meanwhile, the tunnel surrounding rock is soft in soil quality due to continuous rainfall, the stability of primary support cannot be guaranteed, and the steel arch cannot bear the upper pressure to sink. The primary support structure invades the limit of the secondary lining structure, so that the primary support structure requiring deformation invasion has high dismantling speed, and adverse conditions such as collapse and the like caused by overlong exposure time of surrounding rock are avoided; when the arch changing construction is carried out, the disturbance is required to be small, and the disturbance to surrounding rocks which need to be enlarged and dug is reduced as much as possible. The arch changing process has high risk, and the improper treatment method is extremely easy to cause safety accidents, thereby causing loss of personnel life and company property. At present, a method for changing arches in karst areas (namely, water is used for carbonate rock) does not exist, and in the process of changing arches in karst areas, small disturbance, high efficiency and stable support are required. Therefore, a three-step arch changing method for the collapse position of the shallow tunnel, which has higher safety, can ensure the stability of the primary support and is convenient for construction operation, is urgently needed.
Disclosure of Invention
The invention aims to provide a three-step construction arch changing method for a primary support limit position of a shallow tunnel, so that the defects that the existing method for changing the arch in a karst area is not specially used, and the defects of small disturbance, high efficiency and stable support in the arch changing process cannot be ensured are overcome.
In order to achieve the purpose, the invention provides a three-step construction arch changing method for a primary support limit position of a shallow tunnel, which comprises the following steps:
(1) And (3) preparation of construction: in the arch changing section of the tunnel, measuring the profile line of the section of the tunnel intrusion primary support, drawing a section chart, and determining and marking the arch changing range;
(2) Surface treatment: the earth surface of the tunnel arch-changing section is surveyed, and water seepage prevention treatment is carried out;
(3) Back pressure backfilling in the hole: in order to ensure the stability of the limited primary support, back pressure backfilling is carried out in the tunnel of the tunnel arch-changing section, and the height of soil body of the back pressure backfilling is 1000-1500 mm higher than that of the upper step connecting steel plate;
(4) Temporary arch sleeving construction: after back pressure backfilling in the tunnel is completed, constructing a temporary sleeve arch at the front end of the tunnel arch-changing section when the settlement of the limited primary support tends to be stable;
(5) Leading greenhouse construction: after the temporary sleeve arch construction is completed, the construction of the advanced pipe shed is started, and the self bearing capacity of surrounding rock is improved through grouting; before construction, in order to adapt to the pressure injection of the actual surrounding rock, a pressure injection experiment is carried out firstly to determine proper grouting effect, pressure injection pressure, pressure injection flow and pressure injection quantity; during construction, drilling construction is carried out from the vault position to two sides, and deformation monitoring is carried out on the initial support for limiting invasion in a hole in the construction process;
(6) And (5) removing the intrusion primary support: after the advanced greenhouse construction is completed, removing the primary support for the upper step intrusion limit; when arch changing construction is carried out, removing the primary supports for intrusion limit on a truss-by-truss basis, and carrying out support installation on the truss-by-truss basis; before the infringement primary support is removed, measuring and lofting are firstly carried out, an infringement range is determined, marks are made, and an artificial hand-held air pick manually removes the infringement primary support; measuring and lofting after the intrusion primary support is removed, determining the section expanding and digging size, expanding and digging by adopting a manual cooperation small excavator, and timely clearing the removed intrusion primary support and the expanded and dug rock and soil; in the process of primary support removal and expansion excavation, taking attention to surrounding rock conditions, if the surrounding rock is found to be broken and fall, immediately stopping construction, sealing a removal surface by using sprayed concrete, and finally, carrying out radial grouting to stabilize the surrounding rock;
(7) Primary support construction of an upper step: the primary support of the upper step is constructed one by one according to the condition of removing the primary support of the upper step, the steel arch frame of the primary support of the upper step is removed, and the steel arch frame of the primary support of the upper step is constructed;
(8) Temporary inverted arch support construction: after the primary support construction of the upper step is completed, timely constructing a temporary inverted arch of the upper step;
(9) And (3) primary support construction of middle and lower steps: after the temporary inverted arch construction of the upper step is completed, excavating a middle step back pressure soil body; after the excavation of the middle step back pressure soil body is completed, removing the middle step intrusion primary support, wherein the removal of the middle step intrusion primary support needs staggered construction, removing the steel arch of the middle step intrusion primary support, and then constructing the steel arch of the middle step primary support to prevent the temporary inverted arch of the upper step from being suspended; timely constructing a middle step temporary inverted arch after the primary support construction of the middle step is completed; the construction process of the lower step primary support is the same as that of the middle step primary support, firstly, the back pressure soil body of the lower step is excavated in a staggered mode, then the lower step intrusion primary support is removed, and finally, the lower step primary support is constructed;
(10) Inverted arch and filling layer construction: when the inverted arch is excavated, if the inverted arch substrate is an earthen stratum, carrying out bearing capacity detection, and when the bearing capacity detection does not meet the design requirement, changing and filling concrete; immediately constructing an inverted arch steel frame after the inverted arch substrate is processed; after the inverted arch steel frame construction is completed, concrete is sprayed to form an inverted arch primary support, so that the upper, middle and lower step primary supports and the inverted arch primary support form a new primary support of a closed loop;
(11) Removing the temporary support: removing the temporary inverted arch after the whole construction of the new primary support of the whole ring is completed; when the temporary inverted arch is removed, a mode of removing the inverted arch frame by frame is adopted;
(12) Repeating the steps (6) to (11), and sequentially carrying out arch changing construction on the limited primary support from the front and back directions of the tunnel arch changing section until the whole tunnel arch changing section finishes arch changing work; when the arch changing construction of the whole tunnel arch changing section is completed, the temporary sleeve arch can be removed;
(13) And (3) performing secondary lining construction: and finally, performing secondary lining construction.
Preferably, in the above technical solution, in step (1), before determining the arch changing range, lofting the middle pile, measuring lofting the middle pile every 3000mm in the longitudinal direction by the tunnel arch changing section, marking the position of the middle pile point, recording the corresponding elevation of the middle pile point, and determining whether there is an elevation difference; and then, a total station is arranged on the middle pile point, the profile line of the cross section of the tunnel intrusion primary support is measured, during measurement, data is collected from the inverted arch surface on one side, the data is collected once every 500 mm-1000 mm along the profile line, and a cross section diagram is drawn.
Preferably, in the above technical solution, in step (2), when the earth surface of the arch-changing section of the tunnel is surveyed, the condition of the sinking section of the tunnel burial depth is measured, and the method is used for guiding the arch-changing construction in the tunnel; meanwhile, observing the earth surface in the range of the contour line of the tunnel arch-exchanging section, plugging the position of the earth surface cracking by adopting cement mortar, and excavating a temporary intercepting ditch along the range of the contour line of the tunnel arch-exchanging section; if a subsidence or funnel-shaped sunken area exists on the ground surface, backfilling the area into a tortoiseshell shape, and ensuring that the backfilled soil body is at least 500mm higher than the original ground surface; and meanwhile, covering waterproof cloth on the ground surface of the tunnel arch-changing section.
Preferably, in the above technical scheme, in the step (4), the length of the temporary sleeve arch is 5000mm, and when in construction, I20b I-steel is adopted as the sleeve arch steel frame; when the steel arches of the arch sleeving steel frame need to be lengthened or connected, connecting steel plates are adopted for connection, and phi 22 connecting steel bars are adopted for connecting each steel arch to form a whole; after the steel arch is installed, installing a guide pipe with phi 127 multiplied by 4mm, welding the guide pipe and the steel arch by using phi 16 steel bars, and tilting the guide pipe upwards for 3-5 degrees during installation; the guide pipes are distributed at intervals along the arc direction of the sleeve arch steel frame, and the distance between two adjacent guide pipes is 500mm; after the sleeve arch steel frame and the guide pipe are installed, adopting concrete with the grade of C25 to spray the sleeve arch steel frame into a whole.
Preferably, in the above technical scheme, in step (5), the steel pipe of the leading greenhouse is a hot-rolled seamless steel pipe with diameter of phi 108×6mm, grouting holes with diameter of 16mm are reserved on the steel pipe, and the grouting holes are arranged in a quincuncial shape with interval of 200 mm; according to the length of the pipe section of the steel pipe, when the drilling depth reaches the length of a single section of the steel pipe, immediately installing the steel pipe, and continuing drilling construction; in order to ensure the strength of the connecting part of the leading greenhouse, each section of steel pipe is connected by screw threads; and after the steel pipe is installed in place, grouting the steel pipe, removing slurry in the pipe in time after grouting is finished, and tightly filling the steel pipe with M30 cement mortar to enhance the rigidity and strength of the advanced greenhouse.
Preferably, in the technical scheme, in the step (7) and the step (9), primary supports of the upper, middle and lower steps are supported by adopting an S5-A type lining type; when the advanced support construction is carried out, the advanced support form adopts the form of an advanced long pipe shed and a double-layer small pipe, the advanced small pipe adopts a seamless steel pipe with phi 42 multiplied by 4mm, the length of the advanced small pipe is 6000mm, and the annular distance between two adjacent advanced small pipes is 40mm; the lock foot steel pipe is a seamless steel pipe with phi 42 multiplied by 4mm, and the length of the lock foot steel pipe is 6000mm; and (3) grouting in time after the construction of the advanced small guide pipe is completed, and before grouting the advanced small guide pipe, performing pressure grouting through a test hole, adjusting grouting parameters suitable for the on-site geological condition, and judging whether grouting materials, grouting proportion and grouting parameters meet grouting design requirements or not through the pressure grouting effect.
Preferably, in the above technical solution, in step (8), the temporary inverted arch of the upper step adopts an I18 steel arch, and the installation space of the steel arch of the temporary inverted arch of the upper step is the same as the installation space of the steel arch of the primary support of the upper step; the steel arch frame of the temporary inverted arch of the upper step is welded with the steel arch frame of the primary support of the upper step by adopting phi 22 steel bars; after the temporary inverted arch of the upper step is installed, concrete is sprayed in time; the construction process of the middle step temporary inverted arch in step (9) is the same as the construction process of the upper step temporary inverted arch.
Preferably, in the above technical solution, in step (10), the grade of the concrete to be replaced is C15; when the inverted arch substrate is an earthen stratum, the inverted arch has a one-time excavation length of 3000mm.
Compared with the prior art, the invention has the following beneficial effects:
1. the arch changing method can be used for changing the arch specifically for karst areas, and the stability of surrounding rocks is ensured; before arch changing, the earth surface of the tunnel arch changing section is firstly surveyed, and water seepage prevention treatment is carried out, so that the earth surface water seepage caused by rainfall is prevented, and secondary influence is caused in the tunnel; and back pressure is carried out on backfill in the hole, temporary sleeve arch and advanced pipe shed are constructed before arch replacement for pre-supporting, the stability of supporting is improved, and the construction safety is ensured;
2. the arch changing method of the invention divides the limited primary support into three steps of upper, middle and lower steps for dismantling and installing in sequence, when each step primary support is constructed, a new steel arch frame is immediately installed after the steel arch frame is dismantled, arch changing is carried out one by one, when the limited primary support is dismantled, a manual hand-held air pick is adopted for manual dismantling, when the limited primary support is expanded, a manual cooperation small excavator is adopted for expanding and excavating, and the disturbance to the surrounding environment is small; after the primary support construction of the upper and middle steps is completed, the temporary inverted arch is constructed in time, so that the stability of the new primary support can be improved; after the construction of the primary support of the lower step is completed, constructing an inverted arch, closing the new primary support into a ring, and further improving the stability of the new primary support; in the arch changing process, the intrusion primary support is combined with the new primary support, so that the efficiency is high, and the adverse conditions of collapse and the like caused by overlong exposure time of surrounding rock can be avoided.
Drawings
FIG. 1 is a construction flow chart of a three-step construction arch changing method at the primary support limit of a shallow tunnel according to the invention.
Fig. 2 is a schematic structural view of a temporary arch according to the present invention.
Fig. 3 is a schematic structural view of the advanced greenhouse according to the present invention.
FIG. 4 is a schematic illustration of an S5-A liner type structure in accordance with the present invention.
Fig. 5 is a construction flow diagram of an S5-a lining type according to the present invention.
Fig. 6 is a schematic view of the installation structure of the advance small catheter according to the present invention.
Fig. 7 is a schematic side view of the mounting structure of the advance small catheter according to the present invention.
The main reference numerals illustrate:
1-temporary arch, 2-connecting steel bars, 3-arch steel frame, 4-guide pipe, 5-leading small guide pipe, 6-leading big pipe shed, 7-foot locking steel pipe, 8-anchor rod, 9-S5-A type lining, 10-inner ring leading small guide pipe, 11-steel arch frame and 12-outer ring leading small guide pipe.
Detailed Description
The following detailed description of embodiments of the invention is, therefore, to be taken in conjunction with the accompanying drawings, and it is to be understood that the scope of the invention is not limited to the specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or components.
Fig. 1 to 7 are schematic structural views showing a three-step construction arch changing method at a primary support intrusion site of a shallow tunnel according to a preferred embodiment of the present invention. Referring to fig. 1 to 7, a three-step construction arch changing method for a primary support limit position of a shallow tunnel comprises the following steps:
(1) And (3) preparation of construction: in the arch changing section of the tunnel, the section contour line of the tunnel intrusion primary support is measured, a section diagram is drawn, and the arch changing range is determined and marked.
(2) Surface treatment: the earth surface of the tunnel arch-changing section is surveyed, water seepage prevention treatment is carried out, and earth surface water seepage caused by rainfall is prevented, so that secondary influence is caused in the tunnel.
(3) Back pressure backfilling in the hole: in order to ensure the stability of the limited primary support, back pressure backfilling is carried out in the tunnel of the tunnel arch-changing section, and the height of soil body of the back pressure backfilling is 1000-1500 mm higher than that of the upper step connecting steel plate, so that the stability of the support is improved, and the construction safety is ensured.
(4) Temporary sleeve arch 1 construction: after back pressure backfilling in a tunnel is completed, when the settlement of the limited primary support tends to be stable, a temporary sleeve arch 1 is constructed at the front end of the tunnel arch-changing section, and when the temporary sleeve arch 1 is constructed, a back pressure soil body below the arch waist is not excavated temporarily, so that the construction safety is ensured.
(5) And (3) construction of an advanced greenhouse 6: after the temporary sleeve arch 1 is constructed, the construction of the advanced pipe shed 6 is started, the self bearing capacity of surrounding rock is improved through grouting, the elastic resistance of rock mass to the structure is improved, the stress condition of the structure is improved, and the construction safety is ensured. Before construction of the advanced greenhouse 6, in order to adapt to the pressure injection of the actual surrounding rock, a pressure injection experiment is performed to determine proper grouting effect, pressure injection pressure, flow and injection quantity. When the advanced greenhouse 6 is constructed, drilling construction is carried out from the vault position to two sides, and deformation monitoring is carried out on the primary support for limiting invasion in the tunnel in the construction process.
(6) And (5) removing the intrusion primary support: and after the construction of the advanced greenhouse 6 is completed, removing the primary support for limiting the invasion of the upper step. When arch changing construction is carried out, the primary supports for intrusion limit are removed from roof truss to roof truss, and support installation is carried out from roof truss to roof truss. Before the primary support is removed, measuring and lofting are firstly carried out, the primary support is removed, the primary support is determined, the primary support is manually removed by a manual hand-held pneumatic pick, sprayed concrete of the primary support steel arch segment is stripped, and connecting bolts at the connecting steel plate of the steel arch segment are removed. When the sprayed concrete, the steel arch and the reinforcing steel meshes are removed, a mini excavator can be used for cooperation removal, but blasting removal cannot be used, so that the concrete at other parts is prevented from being damaged. After the intrusion primary support is removed, measuring and lofting are carried out, the section expansion and excavation size is determined, and the artificial cooperation with a small excavator is adopted for expansion and excavation, so that the removed intrusion primary support and the expanded and excavated rock and soil are cleared in time. In the process of primary support removal and expansion excavation, the surrounding rock condition is to be noted, if the surrounding rock is found to be broken and fall, the construction is immediately stopped, the removal surface is sealed by sprayed concrete, and finally radial grouting is carried out, so that the surrounding rock is stabilized, and the construction safety is ensured.
(7) Primary support construction of an upper step: the primary support of the upper step is constructed one by one according to the condition of removing the primary support of the upper step, the steel arch of the primary support of the upper step is removed, and the steel arch of the primary support of the upper step is constructed. The steel arch centering of the primary support of the upper step is installed in time after the steel arch centering of the primary support of the upper step is removed, a connecting steel plate is placed on a solid foundation during the installation of the steel arch centering, and a foot locking anchor rod is constructed, so that the stability of the steel arch centering is ensured. The combined use of the limited primary support dismantling and the new primary support installation has high efficiency, and can avoid the adverse conditions of collapse and the like caused by overlong exposure time of surrounding rock.
(8) Temporary inverted arch support construction: after the construction of the primary support of the upper step is completed, in order to ensure the stability of the primary support of the upper step, the temporary inverted arch of the upper step is constructed in time so as to support the primary support of the upper step.
(9) And (3) primary support construction of middle and lower steps: and after the temporary inverted arch construction of the upper step is completed, excavating a middle step back pressure soil body. After the excavation of the middle step back pressure soil body is completed, the middle step intrusion primary support is removed, staggered construction is needed for removing the middle step intrusion primary support, the steel arch of the middle step intrusion primary support is removed, and the steel arch of the middle step primary support is constructed, so that the temporary inverted arch of the upper step is prevented from being suspended. Namely, after the steel arch frame of the middle step primary support is removed, the steel arch frame of the middle step primary support is installed in time, a connecting steel plate is placed on a solid foundation during the installation of the steel arch frame, and a foot locking anchor rod is constructed, so that the stability of the steel arch frame is ensured. And (3) constructing the middle step temporary inverted arch in time after the primary support construction of the middle step is completed. And then carrying out construction of a lower step primary support, wherein the lower step primary support construction process is the same as the middle step primary support construction process, firstly excavating a lower step back pressure soil body in a staggered manner, then dismantling the lower step intrusion primary support, and finally constructing the lower step primary support. When the middle step primary support and the lower step primary support are constructed, the middle step primary support and the upper step primary support are connected into a whole, and the lower step primary support and the middle step primary support are connected into a whole.
(10) Inverted arch and filling layer construction: when the inverted arch is excavated, if the inverted arch substrate is a soil stratum, the bearing capacity detection is needed, and when the bearing capacity detection does not meet the design requirement, the concrete needs to be replaced, so that the bearing capacity of the inverted arch substrate is improved. Immediately constructing an inverted arch steel frame after the inverted arch substrate is processed; after the inverted arch steel frame construction is completed, concrete is sprayed to form an inverted arch primary support, so that the upper, middle and lower step primary supports and the inverted arch primary support form a new primary support of a closed loop.
(11) Removing the temporary support: and after the whole construction of the new primary support of the whole ring is completed, removing the temporary inverted arch of the upper step and the temporary inverted arch of the middle step. When the temporary inverted arch is removed, a mode of removing the inverted arch frame by frame is adopted. And when dismantling the temporary inverted arch, adopting an artificial pneumatic pick to chisel sprayed concrete between the steel arches, cutting off a temporary connection part between the temporary inverted arch and the primary support steel arches, and dismantling the temporary inverted arch.
(12) And (3) repeating the steps (6) to (11), and sequentially carrying out arch changing construction on the limited primary support from the front and back directions of the tunnel arch changing section, namely, constructing one ring of new primary support, and constructing the other ring of new primary support until the whole tunnel arch changing section finishes the arch changing work. And when the arch changing construction of the whole tunnel arch changing section is completed, the temporary sleeve arch 1 can be removed. When the temporary sleeve arch 1 is removed, firstly, concrete is chiseled, then the steel arch is removed, and finally, the tail end steel pipe of the leading greenhouse 6, which leaks out of the primary supporting surface, is cut. The gun is forbidden when chiseling concrete, prevents that the too big disturbance that causes new primary support of vibration to influence the stability of new primary support.
(13) And (3) performing secondary lining construction: and finally, performing secondary lining construction.
Referring to fig. 1, preferably, in step (1), before determining the arch changing range, lofting of the middle pile is performed, the tunnel arch changing section measures lofting of the middle pile every 3000mm longitudinally, marks positions of middle pile points, and records corresponding elevations of the middle pile points to determine whether elevation differences exist. And then, a total station is arranged on the middle pile point, and the contour line of the tunnel intrusion primary support section is measured. During measurement, data are collected from the inverted arch surface at one side, the data are collected at intervals of 500-1000 mm along the contour line, and a sectional view is drawn.
Referring to fig. 1, preferably, in step (2), when the earth surface of the arch changing section of the tunnel is surveyed, the buried depth of the tunnel in the sinking section is measured and used for guiding the arch changing construction in the tunnel. Meanwhile, observing the earth surface in the range of the contour line of the tunnel arch-exchanging section, plugging the position of the earth surface cracking by adopting cement mortar, and excavating a temporary intercepting ditch along the range of the contour line of the tunnel arch-exchanging section. If a subsidence or funnel-shaped concave area exists on the ground surface, the area needs to be backfilled into a tortoiseshell shape, and the backfill soil body is ensured to be at least 500mm higher than the original ground surface. Meanwhile, waterproof cloth is covered on the ground surface of the tunnel arch-changing section, so that ground surface water seepage caused by rainfall is prevented, and secondary influence is caused in the tunnel.
Referring to fig. 1 and 2, in step (4), the temporary arch 1 preferably has a length of 5000mm, and I20b I-steel is used as the arch steel frame 3 during construction. When the steel arches of the arch steel frame 3 need to be lengthened or connected, the steel arches are connected by adopting connecting steel plates, and each steel arch is connected into a whole by adopting phi 22 connecting steel bars 2. After the steel arch is installed, a guide pipe 4 with phi 127 multiplied by 4mm is installed, phi 16 steel bars are used for welding between the guide pipe 4 and the steel arch, and the guide pipe 4 is inclined upwards by 3-5 degrees during installation. The guide pipes 4 are distributed at intervals along the arc direction of the arch steel frame 3, and the distance between two adjacent guide pipes 4 is 500mm. After the sleeve arch steel frame 3 and the guide pipe 4 are installed, the sleeve arch steel frame 3 is sprayed into a whole by adopting concrete with the grade of C25.
Referring to fig. 1 and 3, in the step (5), preferably, the steel pipe of the leading greenhouse 6 is a hot rolled seamless steel pipe with phi 108×6mm, grouting holes with diameters of 16mm are reserved on the steel pipe, and the grouting holes are arranged in a quincuncial shape with a distance of 200 mm. And according to the length of the pipe section of the steel pipe, when the drilling depth reaches the length of a single section of the steel pipe, immediately installing the steel pipe, and continuing drilling construction. In order to ensure the strength of the connecting part of the leading greenhouse 6, each section of steel pipe is connected by screw threads. After the steel pipe is installed in place, grouting is carried out on the steel pipe, slurry in the pipe is timely removed after grouting is finished, M30 cement mortar is adopted for tightly filling, and the rigidity and the strength of the advanced greenhouse 6 are enhanced.
Referring to fig. 4 to 7, preferably, in step (7) and step (9), both the upper, middle and lower steps primary support is supported by an S5-a type lining 9, and the construction process of the S5-a type lining 9 includes: advanced support construction, primary shotcrete of an excavation face, construction of an anchor rod 8, construction of a reinforcing mesh, installation of a steel arch 11, construction of a foot locking steel pipe 7 and re-shotcrete. In the advance support construction, the advance support form adopts an advance long pipe shed and double-layer small guide pipes, the double-layer small guide pipes comprise an inner ring advance small guide pipe 10 and an outer ring advance small guide pipe 12, the inner ring advance small guide pipe 10 and the outer ring advance small guide pipe 12 comprise a plurality of advance small guide pipes 5 which are distributed at intervals, the advance small guide pipes 5 adopt seamless steel pipes with phi 42 multiplied by 4mm, the length of the advance small guide pipes 5 is 6000mm, and the annular distance between every two adjacent advance small guide pipes 5 is 40mm. The lock foot steel pipe 7 is a seamless steel pipe with phi 42 multiplied by 4mm, and the length of the lock foot steel pipe 7 is 6000mm. And (3) grouting in time after the construction of the leading small guide pipe 5 is completed, and before grouting is carried out on the leading small guide pipe, grouting parameters suitable for the on-site geological conditions are adjusted through test holes, and whether grouting materials, grouting proportion and grouting parameters meet grouting design requirements is judged through grouting effect.
Referring to fig. 1, preferably, in step (8), the upper step temporary inverted arch is an I18 steel arch, and the steel arch installation pitch of the upper step temporary inverted arch is the same as the steel arch installation pitch of the upper step primary support. The steel arch frame of the temporary inverted arch of the upper step is welded with the steel arch frame of the primary support of the upper step by adopting phi 22 steel bars, and each steel arch frame of the temporary inverted arch is welded by using phi 22 steel bars. And after the temporary inverted arch of the upper step is installed, concrete is sprayed in time. The construction process of the middle step temporary inverted arch in step (9) is the same as the construction process of the upper step temporary inverted arch.
Referring to fig. 1, preferably, in step (10), the grade of the concrete to be replaced is C15. In order to ensure construction safety, when the inverted arch substrate is an earthen stratum, the inverted arch is excavated once with the length of 3000mm.
The arch changing method can be used for changing the arch specifically for karst areas, so that the stability of support is improved, the stability of surrounding rock is ensured, the construction safety is ensured, and the disturbance to the surrounding environment is small; in the arch changing process, the limited primary support is combined with the new primary support, so that the efficiency is high, and the adverse conditions of collapse and the like caused by overlong exposure time of surrounding rock can be avoided.
The foregoing descriptions of specific exemplary embodiments of the present invention are presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application to thereby enable one skilled in the art to make and utilize the invention in various exemplary embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.

Claims (8)

1. A three-step construction arch changing method for a primary support limit position of a shallow tunnel is characterized by comprising the following steps:
(1) And (3) preparation of construction: in the arch changing section of the tunnel, measuring the profile line of the section of the tunnel intrusion primary support, drawing a section chart, and determining and marking the arch changing range;
(2) Surface treatment: the earth surface of the tunnel arch-changing section is surveyed, and water seepage prevention treatment is carried out;
(3) Back pressure backfilling in the hole: in order to ensure the stability of the limited primary support, back pressure backfilling is carried out in the tunnel of the tunnel arch-changing section, and the height of soil body of the back pressure backfilling is 1000-1500 mm higher than that of the upper step connecting steel plate;
(4) Temporary arch sleeving construction: after back pressure backfilling in the tunnel is completed, constructing a temporary sleeve arch at the front end of the tunnel arch-changing section when the settlement of the limited primary support tends to be stable;
(5) Leading greenhouse construction: after the temporary sleeve arch construction is completed, the construction of the advanced pipe shed is started, and the self bearing capacity of surrounding rock is improved through grouting; before construction, in order to adapt to the pressure injection of the actual surrounding rock, a pressure injection experiment is carried out firstly to determine proper grouting effect, pressure injection pressure, pressure injection flow and pressure injection quantity; during construction, drilling construction is carried out from the vault position to two sides, and deformation monitoring is carried out on the initial support for limiting invasion in a hole in the construction process;
(6) And (5) removing the intrusion primary support: after the advanced greenhouse construction is completed, removing the primary support for the upper step intrusion limit; when arch changing construction is carried out, removing the primary supports for intrusion limit on a truss-by-truss basis, and carrying out support installation on the truss-by-truss basis; before the infringement primary support is removed, measuring and lofting are firstly carried out, an infringement range is determined, marks are made, and an artificial hand-held air pick manually removes the infringement primary support; measuring and lofting after the intrusion primary support is removed, determining the section expanding and digging size, expanding and digging by adopting a manual cooperation small excavator, and timely clearing the removed intrusion primary support and the expanded and dug rock and soil; in the process of primary support removal and expansion excavation, taking attention to surrounding rock conditions, if the surrounding rock is found to be broken and fall, immediately stopping construction, sealing a removal surface by using sprayed concrete, and finally, carrying out radial grouting to stabilize the surrounding rock;
(7) Primary support construction of an upper step: the primary support of the upper step is constructed one by one according to the condition of removing the primary support of the upper step, the steel arch frame of the primary support of the upper step is removed, and the steel arch frame of the primary support of the upper step is constructed;
(8) Temporary inverted arch support construction: after the primary support construction of the upper step is completed, timely constructing a temporary inverted arch of the upper step;
(9) And (3) primary support construction of middle and lower steps: after the temporary inverted arch construction of the upper step is completed, excavating a middle step back pressure soil body; after the excavation of the middle step back pressure soil body is completed, removing the middle step intrusion primary support, wherein the removal of the middle step intrusion primary support needs staggered construction, removing the steel arch of the middle step intrusion primary support, and then constructing the steel arch of the middle step primary support to prevent the temporary inverted arch of the upper step from being suspended; timely constructing a middle step temporary inverted arch after the primary support construction of the middle step is completed; the construction process of the lower step primary support is the same as that of the middle step primary support, firstly, the back pressure soil body of the lower step is excavated in a staggered mode, then the lower step intrusion primary support is removed, and finally, the lower step primary support is constructed;
(10) Inverted arch and filling layer construction: when the inverted arch is excavated, if the inverted arch substrate is an earthen stratum, carrying out bearing capacity detection, and when the bearing capacity detection does not meet the design requirement, changing and filling concrete; immediately constructing an inverted arch steel frame after the inverted arch substrate is processed; after the inverted arch steel frame construction is completed, concrete is sprayed to form an inverted arch primary support, so that the upper, middle and lower step primary supports and the inverted arch primary support form a new primary support of a closed loop;
(11) Removing the temporary support: removing the temporary inverted arch after the whole construction of the new primary support of the whole ring is completed; when the temporary inverted arch is removed, a mode of removing the inverted arch frame by frame is adopted;
(12) Repeating the steps (6) to (11), and sequentially carrying out arch changing construction on the limited primary support from the front and back directions of the tunnel arch changing section until the whole tunnel arch changing section finishes arch changing work; when the arch changing construction of the whole tunnel arch changing section is completed, the temporary sleeve arch can be removed;
(13) And (3) performing secondary lining construction: and finally, performing secondary lining construction.
2. The method for replacing arch by three steps construction at the primary support limit of a shallow tunnel according to claim 1, wherein in the step (1), before determining the arch replacement range, lofting of a middle pile is carried out, the tunnel arch replacement section measures lofting of the middle pile every 3000mm longitudinally, the positions of the middle pile points are marked, the corresponding elevation of the middle pile points is recorded, and whether elevation difference exists is determined; and then, a total station is arranged on the middle pile point, the profile line of the cross section of the tunnel intrusion primary support is measured, during measurement, data is collected from the inverted arch surface on one side, the data is collected once every 500 mm-1000 mm along the profile line, and a cross section diagram is drawn.
3. The method for changing the arch at the primary support limit of the shallow tunnel according to claim 1, wherein in the step (2), when the earth surface of the arch changing section of the tunnel is surveyed, the buried depth condition of the tunnel in the sinking section is measured and used for guiding the arch changing construction in the tunnel; meanwhile, observing the earth surface in the range of the contour line of the tunnel arch-exchanging section, plugging the position of the earth surface cracking by adopting cement mortar, and excavating a temporary intercepting ditch along the range of the contour line of the tunnel arch-exchanging section; if a subsidence or funnel-shaped sunken area exists on the ground surface, backfilling the area into a tortoiseshell shape, and ensuring that the backfilled soil body is at least 500mm higher than the original ground surface; and meanwhile, covering waterproof cloth on the ground surface of the tunnel arch-changing section.
4. The method for changing the arch at the primary support limit of the shallow tunnel by three steps construction according to claim 1, wherein in the step (4), the length of the temporary sleeve arch is 5000mm, and I20b I-steel is adopted as a sleeve arch steel frame during construction; when the steel arches of the arch sleeving steel frame need to be lengthened or connected, connecting steel plates are adopted for connection, and phi 22 connecting steel bars are adopted for connecting each steel arch to form a whole; after the steel arch is installed, installing a guide pipe with phi 127 multiplied by 4mm, welding the guide pipe and the steel arch by using phi 16 steel bars, and tilting the guide pipe upwards for 3-5 degrees during installation; the guide pipes are distributed at intervals along the arc direction of the sleeve arch steel frame, and the distance between two adjacent guide pipes is 500mm; after the sleeve arch steel frame and the guide pipe are installed, adopting concrete with the grade of C25 to spray the sleeve arch steel frame into a whole.
5. The method for changing arch at the primary support limit of the shallow tunnel by three steps construction according to claim 1, wherein in the step (5), steel pipes of the advanced greenhouse are hot rolled seamless steel pipes with phi 108 multiplied by 6mm, grouting holes with the diameter of 16mm are reserved on the steel pipes, and the grouting holes are arranged in a quincuncial shape with the interval of 200 mm; according to the length of the pipe section of the steel pipe, when the drilling depth reaches the length of a single section of the steel pipe, immediately installing the steel pipe, and continuing drilling construction; in order to ensure the strength of the connecting part of the leading greenhouse, each section of steel pipe is connected by screw threads; and after the steel pipe is installed in place, grouting the steel pipe, removing slurry in the pipe in time after grouting is finished, and tightly filling the steel pipe with M30 cement mortar to enhance the rigidity and strength of the advanced greenhouse.
6. The method for changing arch at three steps of shallow tunnel primary support intrusion limit according to claim 1, wherein in the step (7) and the step (9), the upper, middle and lower steps primary supports are supported by adopting an S5-A type lining type; when the advanced support construction is carried out, the advanced support form adopts the form of an advanced long pipe shed and a double-layer small pipe, the advanced small pipe adopts a seamless steel pipe with phi 42 multiplied by 4mm, the length of the advanced small pipe is 6000mm, and the annular distance between two adjacent advanced small pipes is 40mm; the lock foot steel pipe is a seamless steel pipe with phi 42 multiplied by 4mm, and the length of the lock foot steel pipe is 6000mm; and (3) grouting in time after the construction of the advanced small guide pipe is completed, and before grouting the advanced small guide pipe, performing pressure grouting through a test hole, adjusting grouting parameters suitable for the on-site geological condition, and judging whether grouting materials, grouting proportion and grouting parameters meet grouting design requirements or not through the pressure grouting effect.
7. The method for changing an arch at a three-step construction site of a primary support of a shallow tunnel according to claim 1, wherein in the step (8), an I18 steel arch is adopted as an upper step temporary inverted arch, and the installation interval of the steel arch of the upper step temporary inverted arch is the same as the installation interval of the steel arch of the primary support of the upper step; the steel arch frame of the temporary inverted arch of the upper step is welded with the steel arch frame of the primary support of the upper step by adopting phi 22 steel bars; after the temporary inverted arch of the upper step is installed, concrete is sprayed in time; the construction process of the middle step temporary inverted arch in step (9) is the same as the construction process of the upper step temporary inverted arch.
8. The method for changing arch in three steps construction at the primary support limit of a shallow tunnel according to claim 1, wherein in the step (10), the concrete grade of the changing filling is C15; when the inverted arch substrate is an earthen stratum, the inverted arch has a one-time excavation length of 3000mm.
CN202310650053.7A 2023-06-02 2023-06-02 Three-step construction arch changing method for primary support intrusion limit part of shallow tunnel Pending CN116607975A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117231248A (en) * 2023-11-14 2023-12-15 北京交通大学 Method for disassembling and replacing damaged tunnel lining

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117231248A (en) * 2023-11-14 2023-12-15 北京交通大学 Method for disassembling and replacing damaged tunnel lining
CN117231248B (en) * 2023-11-14 2024-01-26 北京交通大学 Method for disassembling and replacing damaged tunnel lining

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