Disclosure of Invention
The invention aims to provide a tunnel entering construction method for passing through a shallow layer high-load highway, which solves the technical problem of tunnel passing through a shallow layer high-load mine highway, ensures the safety of tunnel construction, saves investment and improves economic benefits.
In order to achieve the aim, the invention provides a cave-in construction method for traversing a shallow-layer high-load road, which comprises the following steps:
pouring a concrete wall on the outer side of the tunnel for performing primary maintenance on the tunnel;
drilling at preset positions, which are apart from the arch camber line, of the arch crown of the tunnel and the straight wall section of the tunnel to obtain mounting holes;
sequentially pressing at least two pipe sheds into any one mounting hole, and welding the two adjacent pipe sheds;
a grouting guide pipe is arranged in the pipe shed, and consolidation grouting is carried out in the grouting guide pipe;
entering the tunnel to crush surrounding rock, and performing primary support after slag is discharged out of the tunnel;
and installing a lining template and lining reinforced concrete in the tunnel, and repeatedly executing the step of entering the tunnel to crush the surrounding rock.
Optionally, the step of pouring a concrete wall outside the tunnel for performing preliminary maintenance on the tunnel includes:
Installing first anchor rods on the outer side of the tunnel, welding the first anchor rods and first arch frames, and arranging at least two groups of first arch frames at intervals along the direction close to the tunnel;
all the first arch frames are bound through a first steel mesh sheet;
and installing a pouring template, and pouring concrete to obtain the concrete wall.
Optionally, before the step of installing the first anchor rod on the outer side of the tunnel and welding the first anchor rod and the first arch, the method further comprises:
according to the elevation of the tunnel entrance, after leveling the elevation of the bottom plate of the tunnel, laying a first steel plate, wherein the two side edges of the first steel plate are 80-120mm wider than the tunnel of the tunnel;
and the step of installing the first anchor rod outside the tunnel comprises:
and a first anchor rod is arranged on the first steel plate.
Optionally, get into the tunnel and carry out broken country rock, after slagging tap to outside the tunnel, carry out preliminary bracing's step, include:
entering the tunnel to crush surrounding rock, and utilizing an air pick to trim, and conveying the slag out of the tunnel;
when the tunnel excavation length is 0.8m-1.5m, laying a second steel plate, extending along the interior of the tunnel compared with the first steel plate, and welding the second steel plate and the first steel plate;
A second anchor rod is arranged on the second steel plate, the second anchor rod and the second arch frames are welded, and at least two groups of the second arch frames are arranged at intervals in the inner direction of the tunnel;
and all the second arch frames are bound through a second steel bar net piece for primary support.
Optionally, the interval between two adjacent groups of the first arches is 900-; the first steel plate and the second steel plate are 40-60mm in thickness and 3-4m in length.
Optionally, the diameter of the mounting hole is 130-150mm, the distance between any two mounting holes is 280-320mm, and the length of the mounting hole is 25-30 m.
Optionally, a grouting conduit is installed in the pipe shed, and the step of performing consolidation grouting in the grouting conduit includes:
installing a grouting guide pipe in the pipe shed, and plugging a gap between the outer wall of the grouting guide pipe and the inner wall of the pipe shed;
performing consolidation grouting in the grouting guide pipe.
Optionally, the step of plugging a gap between an outer wall of the grouting guide pipe and an inner wall of the pipe shed comprises:
and a reducing port with reduced size is arranged at the pipe orifice of the pipe shed, and the reducing port is welded with the outer wall of the grouting guide pipe.
Optionally, the step of performing consolidation grouting in a grouting conduit comprises:
and (3) performing consolidation grouting in the grouting guide pipe through cement paste, wherein the water-cement ratio of the cement paste is (0.95-1.01):1, and the grouting pressure is 0.5-1 MPa.
Optionally, between the step of performing preliminary bracing and the step of installing a lining form and lining reinforced concrete in the tunnel, the method further includes:
when the tunnel excavation length is 2.8m-3.5m, the tunnel is bound with double-layer steel bars and outer-side steel bars located on the outer sides of the double-layer steel bars, and the section diameter of the double-layer steel bars is larger than that of the outer-side steel bars.
Compared with the background art, the tunnel entering construction method for traversing the shallow heavy-load highway provided by the embodiment of the invention comprises the following steps of firstly, before the tunnel enters, performing pipe shed grouting reinforcement on soil around the tunnel; namely, a concrete wall is poured at the outer side of the tunnel at first for carrying out primary maintenance on the tunnel; then, excavating the tunnel, and drilling at preset positions, which are arranged below the arch crown of the tunnel and the straight wall section of the tunnel and are separated from the arch lifting line, to obtain mounting holes; sequentially pressing at least two pipe sheds into any one mounting hole, and welding two adjacent pipe sheds; mounting a grouting guide pipe in the pipe shed, and performing consolidation grouting in the grouting guide pipe; entering a tunnel to crush surrounding rock, and performing primary support after slag is discharged out of the tunnel; and installing a lining template in the tunnel, lining the reinforced concrete, and repeatedly performing the step of entering the tunnel to crush the surrounding rock.
The tunnel entering construction method for passing through the shallow layer heavy-load highway can effectively reduce the influence of the heavy load above the tunnel on the deformation of the excavated earth surface, ensure the stability of shallow layer excavation at the tunnel entering section, accelerate the construction progress, solve the technical problem of tunnel passing through the shallow layer heavy-load mine highway, ensure the safety of tunnel construction, save investment and improve economic benefit.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
The embodiment of the invention provides a tunnel entering construction method for passing through a shallow layer heavy-load road, which refers to the attached figure 1 of the specification, wherein a tunnel is positioned below a heavy-load mine road, and the construction method comprises the following steps:
pouring a concrete wall on the outer side of the tunnel for performing primary maintenance on the tunnel;
drilling at preset positions, which are apart from the arch wire, of the vault of the tunnel and the straight wall section of the tunnel to obtain mounting holes;
sequentially pressing at least two pipe sheds into any one mounting hole, and welding two adjacent pipe sheds;
mounting a grouting guide pipe in the pipe shed, and performing consolidation grouting in the grouting guide pipe;
Entering a tunnel to crush surrounding rock, and performing primary support after slag is discharged out of the tunnel;
and installing a lining template in the tunnel, lining the reinforced concrete, and repeatedly performing the step of entering the tunnel to crush the surrounding rock.
Aiming at the step of pouring a concrete wall on the outer side of a tunnel for carrying out primary maintenance on the tunnel, namely before the tunnel enters the tunnel, carrying out pipe shed grouting reinforcement on soil around the tunnel, wherein the grouting range is 3-5 times of the width of the tunnel, grouting is respectively carried out on the left side and the right side of the tunnel by about 15m, grouting is carried out on the upper part of the tunnel to a road, grouting is carried out on the bottom of the tunnel to a basement rock by about 13.5m, grouting is carried out on the extension box culvert direction of the tunnel by 10m, and the width of the tunnel is 4 m; the method specifically comprises the following steps:
installing first anchor rods on the outer side of the tunnel, welding the first anchor rods and the first arch frames, and arranging at least two groups of first arch frames at intervals along the direction close to the tunnel;
all the first arch frames are bound through the first steel mesh sheet;
and installing a pouring template, and pouring concrete to obtain the concrete wall.
Certainly, in order to realize the installation of the first anchor rod and the first arch, firstly, a first steel plate is paved after the elevation of a bottom plate of the tunnel is leveled according to the elevation of a tunnel entrance, and the two side edges of the first steel plate are 80-120mm wider than the tunnel; and mounting a first anchor on the first steel plate.
In other words, in the first step, according to the elevation of the tunnel portal, after leveling the elevation of the bottom plate, the first steel plate with the thickness of 50mm can be laid, the two sides of the first steel plate are 100mm wider than the roadway, and the size of the first steel plate can be set to be 3.6m long by 0.2m wide by 0.05m thick.
Secondly, drilling at an exposed section 3m outside the tunnel by adopting an YT28 drilling machine, and installing phi 20 first anchor rods, wherein 2 anchor rods are arranged in each group, the number of the anchor rods is two, the end parts of the first anchor rods are welded and connected with a first arch centering (specifically a 16# I-steel arch centering), and the distance between the first arch centering can be set to be 1000 mm;
thirdly, binding by using a first steel bar net piece (which can be a phi 8 x @150 steel bar net piece) after 3I-steel arch frames are installed;
and fourthly, installing a pouring template, reserving a follow-up sleeve hole, pouring concrete and curing the concrete wall.
And finishing the primary maintenance of the tunnel.
Carry out broken country rock to getting into the tunnel, after slagging tap outside the tunnel, carry out preliminary bracing's step, include:
entering a tunnel to crush surrounding rock, finishing by using an air pick, and conveying the slag out of the tunnel;
when the tunnel excavation length is 0.8m-1.5m, laying a second steel plate 1, extending the second steel plate 1 along the interior of the tunnel compared with the first steel plate, and welding the second steel plate 1 and the first steel plate;
The second anchor rods 2 are installed on the second steel plate 1, the second anchor rods 2 and the second arch frames 8 are welded, and the inner directions of the tunnels of at least two groups of second arch frames 8 are arranged at intervals;
and all the second arch frames 8 are bound through the second reinforcing mesh 4 for primary support.
Referring to the description and the attached drawing 1, the vault of the tunnel can be drilled by a 90A guide drilling machine through a reserved hole and a following pipe, the diameter of the drilled hole is phi 146, the drilled holes are arranged at intervals of 300mm, and the length of the drilled hole is 28.3 m;
drilling holes with diameter phi 146 in a straight wall section of the tunnel through reserved holes and follow pipes at a distance of 600mm below the arch wire, wherein the holes are arranged at intervals of 300mm, and the length of the holes is 28.3 m;
cleaning the hole after the drilling of the pipe is finished;
the installation holes can be obtained through the above method, and it can be seen that the diameter of the installation hole can be set to 130-.
Then, a first 9m flower pipe shed with the length phi of 89mm, namely the pipe shed 3, is pressed into each mounting hole, and the position of the pipe shed 3 is the position of the mounting hole. The pipe shed 3 can adopt seamless steel pipes, the wall thickness delta is 5mm, the outer ring is provided with annular grouting holes with the diameter of phi 10mm, and the distance between the annular grouting holes is 600 mm.
The second pipe shed 3 is welded with the first pipe shed 3 until the 28.3m shallow pipe shed is installed hole by hole;
Next, the follow-up casing can be pulled out hole by a 90A pilot drill;
then installing a phi 20 grouting guide pipe in each mounting hole;
before grouting, a pipe orifice of the pipe shed 3 can be made into a 6cm reducing port by using a 2mm steel plate and welded with the outer wall of a grouting guide pipe, and a reducing port welding plugging plug is connected with a grouting guide pipe screw thread; namely, a grouting guide pipe is arranged in the pipe shed, and a gap between the outer wall of the grouting guide pipe and the inner wall of the pipe shed is sealed; and carrying out consolidation grouting in the grouting guide pipe. It can be seen that the pipe orifice of the pipe shed can be provided with a reducing orifice with reduced size, and the reducing orifice is welded with the outer wall of the grouting guide pipe.
Adopting cement paste for grouting, wherein the water cement ratio of the cement paste is l: the water-cement ratio of the cement paste can be in the range of (0.95-1.01):1, the grouting pressure: 0.5-1.0 MPa, injecting the slurry from the orifice at one time to ensure that the slurry in the pipe is full and compact until the designed grouting pressure or the designed grouting amount is reached;
after the grouting reaches the concrete strength, breaking the surrounding rock by a breaking hammer of a small excavator after entering the hole, manually finishing by an air pick, and conveying slag to the outside of the hole by a loader;
when the excavation length of the tunnel is 1m, extending and laying a second steel plate 1, and welding the second steel plate 1 and the first steel plate together to prevent uneven settlement; wherein the first steel plate and the second steel plate have a thickness of 40-60mm and a length of 3-4 m.
The second anchor rods 2 are welded with the second steel plates 1, the length of each second anchor rod 2 can be set to be 2m, 2 anchor rods are arranged in each group, 6 anchor rods are arranged in total, the end portions of the second anchor rods 2 are connected with second arch arches 8 (specifically, 22# I-steel arch arches) in a welding mode, the distance between the two second arch arches 8 is 300mm, and binding can be carried out through second steel bar meshes (specifically, 4 phi 8@150 steel bar meshes) for primary support; wherein, the interval between two adjacent first arches is 900-.
And when the construction length reaches 3m, binding double-layer steel bars 5 (specifically phi 22 double-layer steel bars) and outer-side steel bars 6 (specifically phi 14 steel bars), wherein the distance between the double-layer steel bars 5 is 120mm, and the distance between the outer-side steel bars 6 is 150 mm. That is, the sectional diameter of the double-layered reinforcing bars 5 is greater than that of the outer reinforcing bars 6.
Installing lining form, lining with reinforced concrete 7,
and (5) performing circular construction according to the method, and repeatedly executing the step of entering the tunnel to crush the surrounding rock until the shallow construction is finished.
According to the tunnel entering construction method for passing through the shallow layer high-load road, provided by the embodiment of the invention, before a tunnel enters a tunnel, a first steel plate is laid on a bottom plate, a first anchor rod and a first arch frame are installed, a concrete wall is poured, drilling is carried out by reserving phi 146 follow-up sleeve holes, a phi 89 steel pipe shed is pressed in, after a sleeve is pulled out, a phi 20 grouting guide pipe is installed for consolidation grouting. After entering the tunnel, the excavator crushes the surrounding rock, the air pick is used manually for cooperation operation, when the operation is 1m, slag is discharged to the outside of the tunnel, a second steel plate is laid, a second arch frame is installed, primary support is carried out, binding reinforcing steel bars and two lining linings are carried out when the construction is 4m, dynamic monitoring is carried out during the construction, and vault and earth surface subsidence measurement is carried out. According to the arrangement, the influence of the large load above the tunnel on the deformation of the excavated earth surface is effectively reduced, the stability of shallow excavation of the tunnel entering section is guaranteed, the construction progress is accelerated, the technical problem that the tunnel penetrates through the shallow large-load mine highway is solved, the safety of tunnel construction is ensured, the investment is saved, and the economic benefit is improved. Obviously, the construction process steps are simplified, the construction is convenient, the safety and the reliability are realized, and the cost is low.
It is noted that, in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity from another entity without necessarily requiring or implying any actual such relationship or order between such entities.
The construction method for entering the hole of the shallow-layer heavy-load road provided by the invention is described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.