CN110617072B - Tunnel excavation construction method for obliquely passing existing operation tunnel at minimum clear distance - Google Patents
Tunnel excavation construction method for obliquely passing existing operation tunnel at minimum clear distance Download PDFInfo
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- 238000009412 basement excavation Methods 0.000 title claims abstract description 62
- 238000010276 construction Methods 0.000 title claims abstract description 30
- 238000012544 monitoring process Methods 0.000 claims abstract description 50
- 239000011435 rock Substances 0.000 claims abstract description 46
- 238000000034 method Methods 0.000 claims abstract description 38
- 239000002689 soil Substances 0.000 claims abstract description 23
- 238000006073 displacement reaction Methods 0.000 claims abstract description 21
- 238000005520 cutting process Methods 0.000 claims abstract description 13
- 230000000149 penetrating effect Effects 0.000 claims abstract description 7
- 238000009826 distribution Methods 0.000 claims abstract description 4
- 239000004568 cement Substances 0.000 claims description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 22
- 239000002002 slurry Substances 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 5
- 238000012360 testing method Methods 0.000 claims description 3
- 230000003014 reinforcing effect Effects 0.000 claims description 2
- 210000001624 hip Anatomy 0.000 claims 3
- 239000011440 grout Substances 0.000 claims 2
- 230000002787 reinforcement Effects 0.000 abstract description 21
- 230000000694 effects Effects 0.000 description 14
- 238000005422 blasting Methods 0.000 description 6
- 238000005553 drilling Methods 0.000 description 5
- 230000005641 tunneling Effects 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 230000007774 longterm Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 239000010438 granite Substances 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 238000004062 sedimentation Methods 0.000 description 2
- 238000009933 burial Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
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Abstract
The invention relates to a tunnel excavation construction method for obliquely penetrating an existing operating tunnel at an extremely small clear distance, which comprises the following steps of: step 1: acquiring rock stratum distribution and surrounding rock physical and mechanical parameters in front of a tunnel face of a tunnel to be excavated; step 2: carrying out asymmetric grouting reinforcement on surrounding rock in front of the tunnel face; and step 3: reserving core soil, excavating an excavating groove by adopting a cutting and grinding mode, and step 4: mounting a supporting structure in the excavation groove; and 5: excavating reserved core soil in a cutting and grinding mode; monitoring the supporting stress state and displacement of the existing operation tunnel in the steps 3 and 5, and 6: obtaining the differential settlement condition of the existing operation tunnel; and 7: grouting surrounding rock below an area where the differential settlement value of the existing operation tunnel is greater than a set value; and 8: the method of the steps 1-7 is adopted to carry out grouting and excavation work of a plurality of steps in sequence, and the construction method can effectively keep the stability of the existing operation tunnel.
Description
Technical Field
The invention relates to the technical field of tunnels and underground engineering, in particular to a tunnel excavation construction method for obliquely penetrating existing operating tunnels at an extremely small clear distance.
Background
The urban subway operation tunnel lines are generally distributed in a network shape, so that the situation that the lines are crossed with each other is inevitable, and a large number of situations that the proposed tunnel penetrates through the existing operation tunnel exist in the construction process of a new subway line. The excavation construction of the underpass tunnel has obvious disturbance influence on the existing operation tunnel, the problems of settlement of the existing operation tunnel, deformation and cracking of a lining structure, ballast bed void and the like are often caused, especially when the planned tunnel obliquely underpass the existing operation tunnel at a minimum clear distance, the obvious torsion effect of the existing operation tunnel can be caused, the uneven deformation is generated on the axial line section of the vertical operation tunnel, the settlement deformation of one side of the existing operation tunnel, which is close to the planned tunnel, is larger, the settlement deformation of the other side of the existing operation tunnel is smaller, and the tunnel structure is likely to be subjected to torsion damage.
Aiming at the working condition that the existing operation tunnel is obliquely penetrated at a minimum clear distance, a drilling and blasting method is a common construction method, and the method mainly adopts a drilling and blasting mode to break rock mass in front of a tunnel face so as to realize excavation and tunneling. The inventors have found that the above method has the following disadvantages: firstly, from short-term construction, blasting impact force in the drilling and blasting method construction process can cause strong disturbance to rock mass above a tunnel face of a planned tunnel, surrounding rock strength is reduced, and when the distance between the planned tunnel and an existing operating tunnel above the planned tunnel is small, the existing operating tunnel is possibly unstable; secondly, from long-term operation, due to drilling and blasting construction, the mechanical property of the rock mass below the existing operation tunnel is reduced, the capability of resisting the long-term dynamic load of the operation train is reduced, the foundation of the existing operation tunnel can be subjected to fatigue failure, and the long-term stability of the operation tunnel cannot be ensured.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, and provides a tunnel excavation construction method for obliquely passing through an existing operation tunnel at a minimum clear distance, which can effectively reduce the torsion effect and disturbance on the existing operation tunnel and ensure the stability of the existing operation tunnel.
In order to achieve the purpose, the invention adopts the following technical scheme:
a tunnel excavation construction method for obliquely penetrating an existing operation tunnel at an extremely small clear distance comprises the following steps:
step 1: and (4) integrating geological survey data and advanced hole-exploring coring test results to obtain rock stratum distribution and surrounding rock physical and mechanical parameters in the excavation influence range of the tunnel in front of the tunnel face of the tunnel to be excavated.
Step 2: and in a step distance range along the axial direction of the tunnel to be excavated, asymmetrically grouting and reinforcing the surrounding rock in front of the tunnel face of the tunnel to be excavated so as to improve the mechanical property of the surrounding rock in the overlapping area of the tunnel to be excavated and the existing operation tunnel.
And step 3: reserving core soil, excavating a digging groove with the depth equal to the step pitch along the edge contour line of the tunnel to be excavated in the cutting and grinding mode on the rock body in front of the tunnel face, and monitoring the supporting stress state and displacement of the existing operation tunnel in the excavating process.
And 4, step 4: and installing a supporting structure in the excavation groove.
And 5: and excavating the reserved core soil by adopting a cutting and grinding mode, and monitoring the supporting stress state and displacement of the existing operation tunnel in the excavating process.
Step 6: and (5) obtaining the differential settlement conditions of different positions on the same section of the existing operation tunnel according to the support stress state and the displacement state of the operation tunnel obtained in the steps (3) and (5).
And 7: and grouting surrounding rock below the area of the differential settlement value of the existing operation tunnel larger than the set value through the tunnel face of the tunnel to be excavated, so that the differential settlement value of the area of the existing operation tunnel larger than the set value is smaller than the set value.
And 8: and (4) grouting and excavating work of a plurality of steps along the axial direction of the tunnel to be excavated is sequentially carried out by adopting the method of the step 1 to the step 7 until all grouting and excavating work is finished.
Further, in step 2, the area in the horizontal range of the asymmetrically grouted and reinforced wall rock is the area in which the projections of the tunnel to be excavated and the existing operation tunnel are overlapped in the horizontal plane, and the area in the vertical range is the area between the contour line of the tunnel to be excavated and the contour line of the existing operation tunnel.
Further, in the step 2, the grouting material is cement single-liquid slurry, the water cement ratio range of the cement slurry is 0.8-1, the water cement ratio range requirement of the cement slurry cannot be too high or too low, too high water cement ratio can cause too much free water in the grouting reinforcement range, the grouting reinforcement effect does not meet the requirement, too low water cement ratio can cause poor groutability of the slurry, the surrounding rock fracture filling rate is too low, and the grouting reinforcement effect does not meet the requirement.
Further, in the step 3, the method for excavating the excavation groove includes: firstly, a first excavation groove part is cut and ground on one side wall of the tunnel along the contour line, then a second excavation groove part is cut and ground on the other side edge along the contour line, finally a third excavation groove part is cut and ground along the contour line of the vault edge of the tunnel, and the first excavation groove part, the second excavation groove part and the third excavation groove part form an excavation groove.
Further, in the step 5, the cutting and grinding motion track of the reserved core soil is an S-shaped track from bottom to top, and the excavation depth of the core soil is equal to the step pitch.
Further, before step 3 and step 5 are performed, a plurality of monitoring points are arranged in the existing operation tunnel and used for monitoring the stress state and displacement of the support, the monitoring points are arranged on a plurality of monitoring sections in the setting area of the existing operation tunnel, each monitoring section is provided with a plurality of monitoring points, and the determination method of the setting area comprises the following steps: determining a corresponding area of a tunnel face of the tunnel to be excavated in the existing operation tunnel, taking the area as a center, setting a boundary of a set area at a set distance along the front and back directions of the axis of the existing operation tunnel, and setting the set area between the two boundaries.
Further, the set distance is 1.5 times of the diameter of the tunnel to be excavated, and the distance between adjacent monitoring sections is equal to the step pitch.
Furthermore, in the same monitoring section, the vault position, the vault bottom position and the two arch waist positions of the existing operating tunnel are respectively provided with a monitoring point, the vault and the two arch waist monitoring points are respectively inserted with a monitoring point at equal intervals, and the vault bottom and the two arch waist monitoring points are respectively inserted with a monitoring point at equal intervals.
Further, in the step 7, the grouting material is cement single-liquid slurry, the water cement ratio range of the cement slurry is 0.8-1, the requirement of the water cement ratio range of the cement slurry cannot be too high or too low, too high water cement ratio can cause too much free water in the grouting range, the grouting reinforcement effect and the lifting effect do not meet the requirement, too low water cement ratio can cause poor grouting performance of the slurry, the surrounding rock crack filling rate is too low, and further the grouting reinforcement effect and the lifting effect do not meet the requirement.
Further, in the step 7, the set value is 0.3cm and does not exceed a differential settlement limit value which can guarantee the operation safety of the train of the existing operation tunnel and the safety of the lining structure.
The invention has the beneficial effects that:
1. according to the construction method, before tunnel face excavation, grouting reinforcement is carried out on the surrounding rock area of the overlapping part of the existing operation tunnel and the tunnel to be excavated, so that the space torsion effect of the existing operation tunnel during tunnel construction to be excavated can be effectively reduced, and uneven settlement and uneven stress of the existing operation tunnel are reduced.
2. According to the construction method, the excavation groove is excavated in a cutting and grinding mode, and then the supporting structure is directly installed, so that the disturbance to the surrounding rock is greatly reduced, the stability of the mechanical property of the surrounding rock below the existing operation tunnel is ensured, and the bearing capacity of the surrounding rock to the existing operation tunnel is ensured.
3. According to the construction method, the supporting structure is directly installed after the excavation groove is excavated, so that the time from excavation to supporting operation is shortened, and the construction method is more favorable for the safety of engineering.
4. The construction method of the invention reserves the core soil when excavating the excavation slot, which is beneficial to ensuring the stability of the tunnel face in the excavation and supporting operation process.
5. The construction method can monitor the supporting stress state and the displacement state of the existing operating tunnel, further obtain the area with overlarge sedimentation of the existing operating tunnel, and perform grouting on the lower part of the area to lift the existing operating tunnel in the area, thereby ensuring that the sedimentation value of the operating tunnel is within the allowable limit value.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.
Fig. 1 is a schematic diagram of a grouting reinforced surrounding rock area in one step of two end parts of a cross part of an existing operating tunnel and a tunnel to be excavated in embodiment 1 of the present invention;
FIG. 2 is a schematic cross-sectional view taken along line A of FIG. 1 in accordance with the present invention;
FIG. 3 is a schematic cross-sectional view taken along line B of FIG. 1 in accordance with the present invention;
FIG. 4 is a schematic cross-sectional view of the excavation of a trench and core soil excavation according to example 1 of the present invention;
FIG. 5 is a schematic longitudinal sectional view of the excavation of a trench and core soil according to example 1 of the present invention;
fig. 6 is a schematic layout view of monitoring points on a monitoring section of an existing operating tunnel according to embodiment 1 of the present invention;
the method comprises the following steps of 1, an existing operation tunnel, 2, a tunnel to be excavated, 3, a cross part, 4, a tunnel face, 4-1, an upper working face, 4-2, a lower working face, 5, a surrounding rock area reinforced by grouting, 6, a step pitch, 7, a grouting hole, 8, an excavation groove, 8-1, a first excavation groove part, 8-2, a second excavation groove part, 8-3, a third excavation groove part, 9, a left tunnel side wall, 10, a right tunnel side wall, 11, a vault tunnel side wall, 12, a supporting structure, 13, a monitoring point and 14, core soil.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
For convenience of description, the words "up", "down", "left" and "right" in the present invention, if any, merely indicate correspondence with up, down, left and right directions of the drawings themselves, and do not limit the structure, but merely facilitate the description of the invention and simplify the description, rather than indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.
As described in the background art, when a tunnel which is located below an existing operation tunnel, is arranged to intersect with the existing operation tunnel, and has a small clear distance from the existing operation tunnel is constructed, the stability of the existing operation tunnel is not guaranteed.
In example 1, which is a typical embodiment of the present application, as shown in fig. 1 to 5, an existing operating tunnel has a vault buried depth of 5.1 to 13.5m, is mainly located in a medium weathered granite stratum, a cover rock thickness is 0.4 to 11.5m, a tunnel structure is a horseshoe-shaped section, the tunnel is constructed by a mining method, a support form is a primary support and a secondary lining composite lining, and a tunnel support design size width × height is 6.3m × 6.6 m. The arch crown burial depth of the tunnel to be excavated at the lower part is 18.3m-20.8m, the tunnel body is mainly positioned in strongly weathered, moderately weathered and slightly weathered granite, the design adopts the mine method to construct upper and lower steps, the excavation step pitch is 0.5m, the horseshoe-shaped section is adopted, the support form is a primary support and secondary lining composite lining, and the width multiplied by the height of the tunnel support design size is 7m multiplied by 7.4 m. The tunnel to be excavated at the lower part obliquely passes through the existing operating tunnel at a small clear distance, the angle formed by the axis of the tunnel at the lower part and the axis of the existing operating tunnel is 25 degrees, and the distance between the lower part and the existing operating tunnel at the upper part is only 1.7 meters within the construction range of the lower passing section, so that the tunnel belongs to a first-level major risk source.
In this embodiment, the portion of the tunnel 2 to be excavated, which does not pass through the existing operating tunnel 1, is constructed by a bench method, and when the tunnel to be excavated is constructed to obliquely pass through the portion 3 of the existing operating tunnel, the tunnel face 4 is divided into an upper working face 4-1 and a lower working face 4-2 by the bench.
The concrete construction comprises the following steps:
step 1: and (2) integrating geological survey data and advanced hole-exploring coring test results to obtain rock bed distribution and surrounding rock physical and mechanical parameters in the influence range of tunnel excavation in front of the tunnel face, wherein the step 1 adopts a common method of the existing tunnel construction, and the specific steps are not described in detail.
Step 2: as shown in fig. 1-3, the wall rock in front of the upper working face of the tunnel to be excavated is subjected to asymmetric grouting reinforcement, specifically, in the distance range of one step 6 along the axial direction of the tunnel to be excavated, the wall rock between the upper contour line of the tunnel to be excavated and the lower contour line of the existing operation tunnel is subjected to grouting reinforcement, the grouting reinforcement wall rock region 5 is the wall rock region between the overlapping parts of the tunnel to be excavated and the existing operation tunnel in the vertical direction, namely, in the step range of the axial direction of the tunnel to be excavated, the region in the horizontal range of the asymmetric grouting reinforcement wall rock is the region in which the projections of the tunnel to be excavated and the existing operation tunnel overlap in the horizontal plane, and the region in the vertical range is the region between the contour line of the tunnel to be excavated and the contour line of the existing operation tunnel.
The grouting reinforcement is carried out in a small conduit grouting mode, a plurality of leading conduits are drilled into a rock mass in front of a tunnel face through grouting holes 7 formed in an upper working face of the tunnel face, the leading conduits are utilized for grouting into surrounding rocks in front of the upper working face, the insertion depth and the insertion angle of the leading conduits meet the requirements of a surrounding rock area needing grouting reinforcement, the grouting material is cement single liquid slurry, the requirement of the cement slurry on the water cement ratio range cannot be too high or too low, too high water cement ratio can cause too much free water in the grouting reinforcement range, the grouting reinforcement effect cannot meet the requirements, too low water cement ratio can cause poor grouting performance of the slurry, the surrounding rock crack filling rate is too low, the grouting reinforcement effect cannot meet the requirements, and finally the water cement ratio of the cement single liquid slurry is controlled within the range of 0.8-1. And in the grouting process, stopping grouting operation of the grouting hole when the grouting pressure reaches 1MPa and the single-hole grouting amount reaches a set standard value.
And step 3: as shown in fig. 4-5, the guiding pipe is removed, and a cantilever type excavator is used for excavating an excavating groove 8 on the upper working face of the tunnel face by cutting and grinding, specifically, the core soil 14 is reserved, firstly, a first excavating groove part 8-1 is excavated on one side of the upper working face along the contour line of the left tunnel side wall 9, then a second excavating groove part 8-2 is excavated on the other side of the upper working face along the contour line of the right tunnel side wall 10, finally, a third excavating groove part 8-3 is excavated along the contour line position of the vault tunnel side wall 11 of the tunnel, the first excavating groove part, the second excavating groove part and the third excavating groove part jointly form an excavating groove, and the depth of the excavating groove is equal to the length of one step.
In the process of excavating the excavation groove, monitoring the supporting stress state and the displacement of the existing operation tunnel in real time, wherein the supporting stress state comprises the stress and the strain state of the lining, and the displacement state comprises the vertical displacement and the horizontal displacement of the support.
In the working process of the cantilever type tunneling machine, the side face of the tunneling head plays a cutting role in soil, the front end face of the tunneling head plays a grinding role in the soil, compared with a traditional drilling and blasting method construction mode, the disturbance of excavation construction on surrounding rocks can be greatly reduced, core soil is reserved when excavation grooves are excavated, and the stability of a tunnel face can be effectively maintained.
And 4, step 4: after the construction of the excavation groove is completed, a primary supporting structure 12 is directly installed in the excavation groove, specifically, a grid arch is erected in the excavation groove, and after the grid arch is erected, rapid hardening concrete is sprayed to embed the grid arch into the concrete, so that the primary supporting structure is formed.
Step 5: after the construction of the primary supporting structure is completed, reserved core soil is excavated by a cantilever type excavator in a cutting and grinding mode, when the core soil is excavated, the movement track of an excavating head of the cantilever type excavator is in an S-shaped track from bottom to top in a left-right circulating mode until the excavation is completed, and the excavation depth of the core soil is equal to the distance of one step.
In the core soil excavation process, the supporting stress state and the displacement of an existing operation tunnel are monitored in real time, the supporting stress state comprises the stress and the strain state of a lining, and the displacement state comprises the vertical displacement and the horizontal displacement of a support.
In the step 5, the lower working surface of the tunnel face is excavated at the same time, the excavation depth is equal to the distance of one step, and the supporting structure is built at the same time.
Step 6: and (5) obtaining the differential settlement conditions of different positions on the same section of the existing operation tunnel according to the support stress state and the displacement state of the operation tunnel obtained in the steps (3) and (5).
And 7: grouting surrounding rock below a region of an existing operating tunnel with a differential settlement value larger than a set value through a tunnel face of the tunnel to be excavated, so that the differential settlement value of the region of the existing operating tunnel with the differential settlement value larger than the set value is smaller than the set value, wherein the set value is not more than the differential settlement limit value which can ensure the train operation safety and the lining structure safety of the existing operating tunnel, the set value is 0.3cm in the embodiment, when the differential settlement difference of different positions on the same section of the existing operating tunnel reaches 0.3cm, the differential settlement value is considered to be overlarge, grouting the surrounding rock region below the part of the existing operating tunnel with the overlarge differential settlement value, lifting the part of the existing operating tunnel with the overlarge differential settlement value through grouting to enable the differential settlement value to meet the requirements, the grouting reinforcement adopts a small conduit grouting mode, and grouting material adopts single cement slurry, the requirement of the cement slurry water cement ratio range cannot be too high or too low, the too high water cement ratio can cause too much free water in the grouting reinforcement range, the grouting reinforcement effect cannot meet the requirement, the too low water cement ratio can cause poor grouting performance of the slurry, the surrounding rock crack filling rate is too low, the grouting reinforcement effect cannot meet the requirement, and finally the water cement ratio of the single cement slurry is controlled to be 0.8-1.
And 8: and (3) sequentially performing grouting and excavation work within a plurality of step distance ranges along the axial direction of the tunnel to be excavated by adopting the method of the step 1 to the step 7 until the excavation of the part of the tunnel to be excavated which obliquely passes through the existing operation tunnel is finished.
Before step 3 is carried out, a plurality of monitoring points are arranged in an existing operation tunnel and used for monitoring the supporting stress state and displacement of the existing tunnel, as shown in fig. 6, a plurality of monitoring sections are arranged in a set area in the existing operation tunnel, the distance of each monitoring section is 0.5m, eight monitoring points 13 are arranged on each monitoring section, one arch crown position is arranged, one arch bottom position is arranged, one arch waist position is arranged at two sides, one monitoring point is inserted between the adjacent monitoring points at equal intervals, the total number of the eight monitoring points is eight, corresponding monitoring instruments are arranged at the monitoring points and used for monitoring the supporting stress state and displacement state, the monitoring instruments can be the existing equipment, and detailed description is not carried out.
The method for determining the set area on the existing operation tunnel comprises the steps of determining a corresponding area of the working face upper portion in the existing operation tunnel before step 2, extending the corresponding area back and forth along the axis direction of the existing operation tunnel by a set distance to obtain two boundaries of the set area, wherein the area between the two boundaries is the set area, the set distance is required to be not less than the excavation influence range of the tunnel to be excavated, the excavation influence range of the tunnel to be excavated is 1.5 times the diameter of the tunnel to be excavated, the distance between adjacent monitoring sections is equal to the step pitch, and in the embodiment, the set distance is 10 m.
Before the step 3 of each step of the tunnel to be excavated works, monitoring points and monitoring instruments are required to be arranged on the existing operation tunnel.
According to the construction method, the asymmetric grouting reinforcement in the step 2 can effectively offset the space torsion effect generated on the existing operation tunnel during the construction of the tunnel to be excavated, so that the uneven settlement and uneven stress of the existing operation tunnel are reduced, and meanwhile, when the excavation groove and the core soil are excavated, the excavation mode of cutting and grinding is adopted.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (9)
1. A tunnel excavation construction method for obliquely passing through an existing operation tunnel at an extremely small clear distance is characterized by comprising the following steps:
step 1: integrating geological survey data and advanced hole-finding coring test results to obtain rock stratum distribution and surrounding rock physical and mechanical parameters in the excavation influence range of the tunnel in front of the tunnel face of the tunnel to be excavated;
step 2: in a step distance range along the axial direction of the tunnel to be excavated, asymmetrically grouting and reinforcing surrounding rocks in front of the tunnel face of the tunnel to be excavated so as to improve the mechanical properties of the surrounding rocks in the overlapping area of the tunnel to be excavated and the existing operating tunnel;
and step 3: reserving core soil, excavating an excavating groove with the depth equal to the step pitch along the edge contour line of the tunnel to be excavated in a cutting and grinding mode on a rock body in front of a tunnel face, and monitoring the supporting stress state and displacement of the existing operating tunnel in the excavating process;
and 4, step 4: mounting a supporting structure in the excavation groove;
and 5: excavating reserved core soil in a cutting and grinding mode, and monitoring the supporting stress state and displacement of the existing operating tunnel in the excavating process;
step 6: obtaining differential settlement conditions of different positions on the same section of the existing operation tunnel according to the support stress state and the displacement of the operation tunnel obtained in the steps 3 and 5;
and 7: grouting surrounding rock below the area of the existing operation tunnel with the differential settlement value larger than the set value, so that the differential settlement value of the area of the existing operation tunnel with the differential settlement value larger than the set value is smaller than the set value;
and 8: and (4) grouting and excavating work of a plurality of steps along the axial direction of the tunnel to be excavated is sequentially carried out by adopting the method of the step 1 to the step 7 until all grouting and excavating work is finished.
2. The method for excavating and constructing the tunnel penetrating the existing operating tunnel with the minimum clear distance in the inclined downward direction according to claim 1, wherein in the step 2, the area in the horizontal range of the asymmetrically grouted and reinforced surrounding rock is an area where projections of the tunnel to be excavated and the existing operating tunnel are overlapped in the horizontal plane, and the area in the vertical range is an area between the contour line of the tunnel to be excavated and the contour line of the existing operating tunnel.
3. The method for excavating a tunnel through an existing operating tunnel at a very small clear distance in an inclined manner according to claim 1, wherein in the step 2, a single cement grout is used as a grouting material, and the water cement ratio of the single cement grout is in a range of 0.8-1.
4. The method for excavating and constructing the tunnel penetrating the existing operating tunnel at the extremely small clear distance and at the low angle according to the claim 1, wherein in the step 3, the excavating method for excavating the groove comprises the following steps: firstly, a first excavation groove part is cut and ground on one side wall of the tunnel along the contour line, then a second excavation groove part is cut and ground on the other side edge along the contour line, finally a third excavation groove part is cut and ground along the contour line of the vault edge of the tunnel, and the first excavation groove part, the second excavation groove part and the third excavation groove part form an excavation groove.
5. The method for excavating and constructing a tunnel with a minimum clear distance obliquely passing through an existing operating tunnel according to claim 1, wherein in the step 5, the movement track of cutting and grinding the reserved core soil is an S-shaped track from bottom to top, and the excavating depth of the core soil is equal to the step pitch.
6. The method for excavating and constructing the tunnel penetrating through the existing operating tunnel with the minimum clear distance in the inclined downward direction according to claim 1, wherein before the step 3 is carried out, a plurality of monitoring points are arranged in the existing operating tunnel for monitoring the stress state and the displacement of the support, the monitoring points are arranged on a plurality of monitoring sections in a set area of the existing operating tunnel, each monitoring section is provided with a plurality of monitoring points, and the determination method of the set area comprises the following steps: determining a corresponding area of a tunnel face of the tunnel to be excavated in the existing operation tunnel, taking the area as a center, setting a boundary of a set area at a set distance along the front and back directions of the axis of the existing operation tunnel, and setting the set area between the two boundaries.
7. The method as claimed in claim 6, wherein the predetermined distance is 1.5 times the diameter of the tunnel to be excavated, and the distance between adjacent monitored sections is equal to the step pitch.
8. The method for excavating and constructing the tunnel penetrating the existing operating tunnel with the minimum clear distance aslant downwards as claimed in claim 6, wherein in the same monitoring section, a vault position, a vault bottom position and two arch waist positions of the existing operating tunnel are respectively provided with a monitoring point, the monitoring points of the vault and the two arch waists are respectively inserted with a monitoring point at equal intervals, and the monitoring points of the vault and the two arch waists are respectively inserted with a monitoring point at equal intervals.
9. The method for excavating a tunnel through an existing operating tunnel at a very small clear distance in an inclined manner according to claim 1, wherein in the step 7, a cement single-liquid slurry is used as a grouting material, and the water cement ratio of the cement slurry is in a range of 0.8-1.
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| CN112196544B (en) * | 2020-10-15 | 2022-10-18 | 中铁二局第二工程有限公司 | Construction method for crossing existing tunnel on contact discharge flue of high-ground-stress soft rock stratum |
| CN112377198B (en) * | 2020-11-02 | 2023-07-14 | 中铁十九局集团广州工程有限公司 | Construction method of up-down crossed tunnel |
| CN112781656A (en) * | 2021-01-18 | 2021-05-11 | 中铁八局集团有限公司 | Method for monitoring safety of intersected existing tunnel during construction of underpass high-speed railway tunnel |
| CN112761675A (en) * | 2021-01-26 | 2021-05-07 | 中铁八局集团昆明铁路建设有限公司 | Construction method of composite support system for extremely-small-clear-distance obliquely downward-penetrating existing subway tunnel |
| CN113389190A (en) * | 2021-06-23 | 2021-09-14 | 武钢集团昆明钢铁股份有限公司 | Rapid treatment method for plate bottom void of narrow area of red viscous soil factory |
| CN113586079B (en) * | 2021-08-24 | 2024-02-13 | 中国电建集团中南勘测设计研究院有限公司 | Tunnel cross intersection structure and construction method thereof |
| CN114000885A (en) * | 2021-10-29 | 2022-02-01 | 四川省交通勘察设计研究院有限公司 | Surrounding rock tunnel tunneling construction method |
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| JP4113007B2 (en) * | 2003-02-26 | 2008-07-02 | 安藤建設株式会社 | Widening method of existing tunnel |
| CN102287195B (en) * | 2011-05-13 | 2014-09-17 | 中铁四局集团第二工程有限公司 | Construction method of large-span tunnel passing through rapid transit railway with shallow tunneling process |
| CN203097896U (en) * | 2013-01-31 | 2013-07-31 | 中铁十四局集团有限公司 | Separated type large-section multi-cavern underpass existing building sedimentation controlling structure |
| CN105350973A (en) * | 2015-10-08 | 2016-02-24 | 同济大学 | Construction method for large-span section loess tunnel under-crossing highway |
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| CN109184743A (en) * | 2018-09-25 | 2019-01-11 | 中铁十二局集团有限公司 | Existing tunnel construction method is worn under circle boulder clay rock compound stratum slurry shield short distance |
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