阅读说明：本技术 一种小净距隧道的加固结构及施工方法 (reinforcing structure of small-clear-distance tunnel and construction method ) 是由 李志军 任刚 王�锋 侯云乾 郭斌 王艳飞 吴雪飞 罗雨 胡曙光 周海霞 王伟 于 2019-07-18 设计创作，主要内容包括：本发明公开一种小净距隧道的加固结构,包括设置在小净距隧道的中岩柱上的中空注浆锚杆、预应力锚杆及导管注浆锚杆,中空注浆锚杆和导管注浆锚杆均一端插入中岩柱中,预应力锚杆两端分别位于小净距隧道的两个隧道内；相邻的两个中空注浆锚杆或导管注浆锚杆上均套接有同一个钢片,中空注浆锚杆和导管注浆锚杆位于隧道内的端部均设置有第一螺帽,预应力锚杆的两端分别设置有第二螺帽。一种小净距隧道的施工方法,首先在先行隧道加装中空注浆锚杆和导管注浆锚杆,然后再在后行隧道加装中空注浆锚杆和导管注浆锚杆,最后加装预应力锚杆。本发明提高了小净距隧道中的中岩柱的稳定性。(the invention discloses a reinforcing structure of a small clear distance tunnel, which comprises a hollow grouting anchor rod, a prestressed anchor rod and a conduit grouting anchor rod which are arranged on a middle rock pillar of the small clear distance tunnel, wherein the uniform ends of the hollow grouting anchor rod and the conduit grouting anchor rod are inserted into the middle rock pillar, and the two ends of the prestressed anchor rod are respectively positioned in two tunnels of the small clear distance tunnel; the two adjacent hollow grouting anchor rods or the conduit grouting anchor rods are sleeved with the same steel sheet, the end parts of the hollow grouting anchor rods and the conduit grouting anchor rods, which are located in the tunnel, are provided with first screw caps, and the two ends of the prestressed anchor rods are provided with second screw caps respectively. A construction method of a small clear distance tunnel comprises the steps of firstly installing a hollow grouting anchor rod and a conduit grouting anchor rod on a first-going tunnel, then installing a hollow grouting anchor rod and a conduit grouting anchor rod on a second-going tunnel, and finally installing a prestressed anchor rod. The invention improves the stability of the medium rock pillar in the small clear distance tunnel.)

1. the utility model provides a reinforced structure in little clear distance tunnel which characterized in that: the small-clearance tunnel construction method comprises a plurality of hollow grouting anchor rods, a plurality of prestressed anchor rods and a plurality of guide pipe grouting anchor rods, wherein the hollow grouting anchor rods, the prestressed anchor rods and the guide pipe grouting anchor rods are arranged on a middle rock pillar of a small-clearance tunnel; the adjacent two cavity slip casting stock or all cup jointed same steel sheet on the pipe slip casting stock, cavity slip casting stock with the pipe slip casting stock is located the tip in the tunnel all is provided with first nut, the steel sheet is located first nut with between the lateral wall of well rock pillar, the both ends of prestressing anchor pole are provided with the second nut respectively.

2. the reinforcement structure of a short-clearance tunnel according to claim 1, wherein: the hollow grouting anchor rod, the prestressed anchor rod and the conduit grouting anchor rod are respectively divided into a plurality of rows to be uniformly distributed, and the same steel sheet is sleeved on two horizontally adjacent hollow grouting anchor rods or conduit grouting anchor rods; the middle of the steel sheet is a convex part, two sides of the steel sheet are flat parts, a through hole for penetrating through the hollow grouting anchor rod, the prestress anchor rod or the conduit grouting anchor rod is formed in each flat part, and the two adjacent steel sheets are opposite in installation direction and are buckled together.

3. The reinforcement structure of a short-clearance tunnel according to claim 2, wherein: the thickness of the flat part is 5mm, and the thickness of the bulge part is 10 mm.

4. The reinforcement structure of a short-clearance tunnel according to claim 1, wherein: the hollow grouting anchor rod is arranged in a 3/5 height region from the top end of the middle rock pillar to the middle rock pillar, the conduit grouting anchor rod is arranged in a 2/5 height region from the bottom end of the middle rock pillar to the middle rock pillar, and the prestress anchor rod is arranged in a 2/5 height region from the middle rock pillar to the 3/5 height region of the middle rock pillar.

5. the reinforcement structure of a short-clearance tunnel according to claim 1, wherein: one end of the second nut is provided with a circular ring, the outer wall of the second nut is provided with four reinforcing ribs, and the reinforcing ribs are fixedly connected with the circular ring.

6. the reinforcement structure of a short-clearance tunnel according to claim 1, wherein: the hollow grouting anchor rod is fixedly connected with surrounding rocks through mud, the hollow grouting anchor rod and the surrounding rocks form a combined reinforcing body, and the conduit anchor rod and surrounding rocks form a compression zone.

7. The reinforcement structure of a short-clearance tunnel according to claim 1, wherein: the hollow grouting anchor rod is inclined upwards, the prestressed anchor rod is horizontal, and the conduit anchor rod is inclined downwards.

8. A construction method of a small clear distance tunnel is characterized by comprising the following steps:

(1) Excavating a small clear distance tunnel in a weak and broken area, wherein smooth blasting is adopted for blasting surrounding rocks, the excavation footage is controlled according to 0.5m, supporting construction is carried out in each cycle, after the excavation of the small clear distance tunnel is finished, a guide pipe is adopted for grouting an anchor rod at the lower part of a middle rock pillar in a preceding tunnel, and the anchoring range is from the bottom end of the middle rock pillar to the height of 2/5; reinforcing the upper part of the middle rock pillar by adopting a hollow grouting anchor rod, wherein the anchoring range is from the position of the middle rock pillar 3/5 of the height from the ground to the top end of the middle rock pillar, the guide pipe grouting anchor rod and the hollow grouting anchor rod are installed and then fixed by installing two horizontal hole steel sheets, the two hole steel sheets are connected in the positive and negative directions, each steel sheet is connected with two adjacent guide pipe grouting anchor rods or hollow grouting anchor rods in the same horizontal line, and the guide pipe grouting anchor rods or the hollow grouting anchor rods in the same horizontal line are connected into a whole by fixing a first screw cap after splicing is completed, and then grouting is carried out;

(2) excavating a backward tunnel, and after the backward tunnel is excavated, grouting an anchor rod on the lower part of a middle rock pillar in the backward tunnel by adopting a guide pipe, wherein the anchoring range is from the bottom end of the middle rock pillar to the height of 2/5; reinforcing the upper part of the middle rock column in the backward tunnel by adopting a hollow grouting anchor rod, wherein the anchoring range is from the position 3/5 of the middle rock column from the ground to the top end of the middle rock column, the guide pipe grouting anchor rod and the hollow grouting anchor rod are installed and then fixed by installing two horizontal hole steel sheets, the two hole steel sheets are connected in a positive and negative way, each steel sheet is connected with two adjacent guide pipe grouting anchor rods or hollow grouting anchor rods on the same horizontal line, the guide pipe grouting anchor rods or the hollow grouting anchor rods on the same horizontal line are connected into a whole by using a first nut after splicing, and then grouting and concrete spraying are carried out;

(3) Installing a prestressed anchor rod in the middle of the middle rock pillar, grouting the prestressed anchor rod, horizontally penetrating the middle rock pillar, and fixing and pre-tightening two ends of the prestressed anchor rod by using a second nut;

(4) Inverted arch excavation and second lining construction: after the tunnel body is excavated, inverted arch support is timely carried out, the ring is closed, concrete is timely sprayed to complete secondary lining support, and all construction processes and technical indexes of lining must meet the requirements of design or specification.

Technical Field

the invention relates to the technical field of geotechnical engineering, in particular to a reinforcing structure of a small-clear-distance tunnel and a construction method.

Background

The stability of the small clear distance tunnel mainly depends on the stability of the middle rock pillar, but the poor stability and easy cracking of the middle rock pillar are main problems which disturb the construction of the small clear distance tunnel, and most of the tunnels are constructed by adopting tunneling successively, so that the excavation blasting of the backward tunnel always influences the stability of the tunnel in advance, even leads to collapse of surrounding rocks and the problem of uncontrolled excavation section.

Disclosure of Invention

The invention aims to provide a small clear distance tunnel reinforcing structure and a construction method, which are used for solving the problems in the prior art, reducing the vertical displacement and the transverse displacement of a middle rock pillar, improving the stability of the middle rock pillar in the small clear distance tunnel, reducing the disturbance of blasting excavation on an excavated section of the tunnel and ensuring the safety of tunnel construction.

in order to achieve the purpose, the invention provides the following scheme: the invention provides a reinforcing structure of a small clear distance tunnel, which comprises a plurality of hollow grouting anchor rods, a plurality of prestressed anchor rods and a plurality of conduit grouting anchor rods, wherein the hollow grouting anchor rods, the prestressed anchor rods and the conduit grouting anchor rods are arranged on a middle rock pillar of the small clear distance tunnel; the adjacent two cavity slip casting stock or all cup jointed same steel sheet on the pipe slip casting stock, cavity slip casting stock with the pipe slip casting stock is located the tip in the tunnel all is provided with first nut, the steel sheet is located first nut with between the lateral wall of well rock pillar, the both ends of prestressing anchor pole are provided with the second nut respectively.

Preferably, the hollow grouting anchor rod, the prestressed anchor rod and the duct grouting anchor rod are respectively divided into a plurality of rows to be uniformly distributed, and the same steel sheet is sleeved on the two horizontally adjacent hollow grouting anchor rods or the duct grouting anchor rods; the middle of the steel sheet is a convex part, two sides of the steel sheet are flat parts, a through hole for penetrating through the hollow grouting anchor rod, the prestress anchor rod or the conduit grouting anchor rod is formed in each flat part, and the two adjacent steel sheets are opposite in installation direction and are buckled together.

Preferably, the thickness of the flat part is 5mm, and the thickness of the convex part is 10 mm.

Preferably, the hollow grouting bolt is arranged in a 3/5 height region from the top end of the middle rock pillar to the middle rock pillar, the conduit grouting bolt is arranged in a 2/5 height region from the bottom end of the middle rock pillar to the middle rock pillar, and the pre-stressed anchor rod is arranged in a 2/5 height region from the middle rock pillar to the 3/5 height region of the middle rock pillar.

Preferably, one end of the second nut is provided with a ring, the outer wall of the second nut is provided with four reinforcing ribs, and the reinforcing ribs are fixedly connected with the ring.

preferably, the hollow grouting anchor rod is fixedly connected with the surrounding rock through mud, the hollow grouting anchor rod and the surrounding rock form a combined reinforcement body, and the conduit anchor rod and the surrounding rock form a compression zone.

preferably, the hollow grouting bolt is inclined upward, the pre-stressed bolt is horizontal, and the conduit bolt is inclined downward.

The invention also provides a construction method of the small clear distance tunnel, which comprises the following steps:

(1) Excavating a small clear distance tunnel in a weak and broken area, wherein smooth blasting is adopted for blasting surrounding rocks, the excavation footage is controlled according to 0.5m, supporting construction is carried out in each cycle, after the excavation of the small clear distance tunnel is finished, a guide pipe is adopted for grouting an anchor rod at the lower part of a middle rock pillar in a preceding tunnel, and the anchoring range is from the bottom end of the middle rock pillar to the height of 2/5; reinforcing the upper part of the middle rock pillar by adopting a hollow grouting anchor rod, wherein the anchoring range is from the position of the middle rock pillar 3/5 of the height from the ground to the top end of the middle rock pillar, the guide pipe grouting anchor rod and the hollow grouting anchor rod are installed and then fixed by installing two horizontal hole steel sheets, the two hole steel sheets are connected in the positive and negative directions, each steel sheet is connected with two adjacent guide pipe grouting anchor rods or hollow grouting anchor rods in the same horizontal line, and the guide pipe grouting anchor rods or the hollow grouting anchor rods in the same horizontal line are connected into a whole by fixing a first screw cap after splicing is completed, and then grouting is carried out;

(2) Excavating a backward tunnel, and after the backward tunnel is excavated, grouting an anchor rod on the lower part of a middle rock pillar in the backward tunnel by adopting a guide pipe, wherein the anchoring range is from the bottom end of the middle rock pillar to the height of 2/5; reinforcing the upper part of the middle rock column in the backward tunnel by adopting a hollow grouting anchor rod, wherein the anchoring range is from the position 3/5 of the middle rock column from the ground to the top end of the middle rock column, the guide pipe grouting anchor rod and the hollow grouting anchor rod are installed and then fixed by installing two horizontal hole steel sheets, the two hole steel sheets are connected in a positive and negative way, each steel sheet is connected with two adjacent guide pipe grouting anchor rods or hollow grouting anchor rods on the same horizontal line, the guide pipe grouting anchor rods or the hollow grouting anchor rods on the same horizontal line are connected into a whole by using a first nut after splicing, and then grouting and concrete spraying are carried out;

(3) Installing a prestressed anchor rod in the middle of the middle rock pillar, grouting the prestressed anchor rod, horizontally penetrating the middle rock pillar, and fixing and pre-tightening two ends of the prestressed anchor rod by using a second nut;

(4) Inverted arch excavation and second lining construction: after the tunnel body is excavated, inverted arch support is timely carried out, the ring is closed, concrete is timely sprayed to complete secondary lining support, and all construction processes and technical indexes of lining must meet the requirements of design or specification.

Compared with the prior art, the reinforcing structure and the construction method of the small clear distance tunnel have the following technical effects:

the reinforcing structure and the construction method of the small clear distance tunnel reduce the vertical displacement and the transverse displacement of the middle rock pillar, improve the stability of the middle rock pillar in the small clear distance tunnel, reduce the disturbance of blasting excavation on the excavated section of the tunnel, and ensure the safety of tunnel construction. The reinforcing structure and the construction method of the small clear distance tunnel effectively reduce the influence of the backward tunnel on the forward tunnel, reduce the pressure influence of the deformation of the middle rock pillar on the forward tunnel, prevent the expansion of the excavation section of the forward tunnel, and prevent the size of the section of the tunnel from being influenced by excavation blasting. Carry out preliminary bracing, divide the rock pillar into three parts through pipe slip casting stock, cavity slip casting stock, prestressed anchorage pole and carry out the anchor of different forms, anchor the rock pillar in the branch region more can make full use of the self-supporting ability of country rock, improved the stability of country rock mechanics parameter, well clamp rock atress change after the change stress state, can also practice thrift economic cost. The conduit grouting anchor rod and the hollow grouting anchor rod are firstly subjected to primary spraying after being driven, so that the early deformation of surrounding rocks is controlled, and the influence of blasting and tunneling of a backward tunnel on a forward tunnel is reduced. The steel sheets with the two holes are simple to manufacture and operate, the steel sheets are fully contacted with the middle rock pillar through fastening of the first threaded sleeve, the steel sheets have a better stress environment, and the steel sheets can play a role in sharing stress deformation for the circumferential surrounding rock primary lining of a bad geological section; the steel sheet maneuverability is big, can adjust the length according to the scope of bad geology section.

drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic structural view of a reinforcing structure of a small clear distance tunnel according to the present invention;

FIG. 2 is a first partial structural view of the reinforcement structure of the small clear distance tunnel according to the present invention;

FIG. 3 is a schematic structural diagram II of a part of the reinforcing structure of the small clear distance tunnel according to the present invention;

FIG. 4 is a first schematic structural diagram of a steel sheet in the reinforcement structure of the small clear distance tunnel according to the present invention;

FIG. 5 is a second structural view of a steel sheet in the reinforcement structure of the small clear distance tunnel according to the present invention;

FIG. 6 is a first schematic structural view of a second nut of the reinforcement structure for a small clearance tunnel according to the present invention;

FIG. 7 is a second schematic structural view of a second nut of the reinforcement structure for a small clearance tunnel according to the present invention;

The concrete grouting anchor rod comprises a hollow grouting anchor rod 1, a pre-stressed anchor rod 2, a conduit grouting anchor rod 3, a concrete layer 4, surrounding rock 5, a first nut 6, a steel sheet 7, a through hole 71, a second nut 8 and a reinforcing rib 81.

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.

The invention aims to provide a small clear distance tunnel reinforcing structure and a construction method, which are used for solving the problems in the prior art, reducing the vertical displacement and the transverse displacement of a middle rock pillar, improving the stability of the middle rock pillar in the small clear distance tunnel, reducing the disturbance of blasting excavation on an excavated section of the tunnel and ensuring the safety of tunnel construction.

in order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1 to 7, the reinforcing structure for a small clear distance tunnel of the present embodiment includes a plurality of hollow grouting anchor rods 1, a plurality of prestressed anchor rods 2, and a plurality of duct grouting anchor rods 3, which are disposed on a middle rock pillar of the small clear distance tunnel, wherein the hollow grouting anchor rods 1 are inclined upward, the prestressed anchor rods 2 are horizontal, and the duct grouting anchor rods are inclined downward; the hollow grouting anchor rod 1 is arranged at the upper part of the middle rock pillar, the conduit grouting anchor rod 3 is arranged at the lower part of the middle rock pillar, the uniform ends of the hollow grouting anchor rod 1 and the conduit grouting anchor rod 3 are inserted into the middle rock pillar, the prestressed anchor rod 2 penetrates through the middle rock pillar, and the two ends of the prestressed anchor rod 2 are respectively positioned in two tunnels of the small-clearance tunnel; the end parts of the hollow grouting anchor rod 1 and the conduit grouting anchor rod 3, which are positioned in the tunnel, are respectively provided with a first nut 6, and the two ends of the prestressed anchor rod 2 are respectively provided with a second nut 8.

The hollow grouting anchor rod 1, the prestressed anchor rod 2 and the duct grouting anchor rod 3 are respectively divided into a plurality of rows to be uniformly distributed, and the same steel sheet 7 is sleeved on the two horizontally adjacent hollow grouting anchor rods 1 or duct grouting anchor rods 3; the middle of each steel sheet 7 is provided with a convex part, two sides of each steel sheet 7 are flat parts, a through hole 71 for penetrating through the hollow grouting anchor rod 1, the prestressed anchor rod 2 or the conduit grouting anchor rod 3 is arranged on each flat part, the installation directions of the two adjacent steel sheets 7 are opposite and are buckled together, the steel sheets 7 are positioned between the first screw caps 6 and the side walls of the middle rock columns, the steel sheets 7 are fully contacted with the middle rock columns through fastening of the first screw sleeves, the steel sheets 7 have a better stress environment, and the steel sheets can play a role of sharing stress deformation for initially lining the circumferential surrounding rock 5 of a bad geological section; the steel sheet 7 has high operability, and the length can be adjusted according to the range of the unfavorable geological section. The thickness of the flat part is 5mm, the thickness of the convex part is 10mm, and the total thickness of the overlapped flat parts of the two steel sheets 7 is just the same as the thickness of the convex part. The hollow grouting anchor rod 1 and the conduit grouting conduit at the same horizontal height are connected into a whole, so that the overall performance parameters of the surrounding rock 5 are improved, the longitudinal displacement of the surrounding rock 5 is effectively reduced, and the occurrence of tunnel annular collapse accidents is reduced

The hollow grouting anchor rod 1 is arranged in a 3/5 height region from the top end of the middle rock pillar to the middle rock pillar, the conduit grouting anchor rod 3 is arranged in a 2/5 height region from the bottom end of the middle rock pillar to the middle rock pillar, and the prestressed anchor rod 2 is arranged in a 2/5 height region from the middle rock pillar to the 3/5 height region of the middle rock pillar.

One end of the second nut 8 is provided with a ring, four reinforcing ribs 81 are arranged on the outer wall of the second nut 8, the reinforcing ribs 81 are fixedly connected with the ring, the contact area of the second nut 8 and the primary lining is increased due to the arrangement of the ring, the effect of the prestressed anchor rod 2 is improved, lateral pressure of the middle rock pillar is given, the stress area of the middle rock body is increased, the horizontal displacement of the surrounding rock 5 of the middle rock pillar is reduced, the cost is low, and the installation is simple and convenient.

the hollow grouting anchor rod 1 is fixedly connected with the surrounding rock 5 through mud, the hollow grouting anchor rod 1 and the surrounding rock 5 form a combined reinforcement body, the self-stability capability of the surrounding rock 5 is improved, the occurrence time of a plastic zone of the middle rock pillar is delayed, and the range of the plastic zone is effectively reduced; the guide pipe anchor rod and the surrounding rock body form a compression belt, and the rock body of the compression belt is in a three-way compression state, so that the guide pipe and the surrounding rock 5 form a combined reinforcing body, and the self-bearing capacity of the surrounding rock 5 is improved.

The embodiment also provides a construction method of the small clear distance tunnel, which comprises the following steps:

(1) Excavating a small-clear-distance tunnel in a weak and broken area, wherein blasting of surrounding rocks 5 adopts smooth blasting, excavation footage is controlled according to 0.5m, supporting construction is carried out in each cycle, after the excavation of the small-clear-distance tunnel is finished, a guide pipe is adopted to pour a grouting anchor rod 3 into the lower part of a middle rock pillar in a preceding tunnel, and the anchoring range is from the bottom end of the middle rock pillar to a 2/5 height position; the upper part of a middle rock column is reinforced by a hollow grouting anchor rod 1, the anchoring range is from the position 3/5 of the middle rock column from the ground to the top end of the middle rock column, a horizontal two-hole steel sheet 7 is installed and fixed after the guide pipe grouting anchor rod 3 and the hollow grouting anchor rod 1 are installed, the two-hole steel sheet 7 is connected in the positive and negative directions, each steel sheet 7 is connected with two adjacent guide pipe grouting anchor rods 3 or hollow grouting anchor rods 1 on the same horizontal line, the guide pipe grouting anchor rods 3 or the hollow grouting anchor rods 1 on the same horizontal line are connected into a whole by a first nut 6 after splicing is completed, and then grouting is performed;

(2) Excavating a backward tunnel, and after the backward tunnel is excavated, grouting an anchor rod 3 at the lower part of a middle rock pillar in the backward tunnel by adopting a guide pipe, wherein the anchoring range is from the bottom end of the middle rock pillar to the height of 2/5; the upper part of a middle rock column in a backward tunnel is reinforced by adopting a hollow grouting anchor rod 1, the anchoring range is from the position 3/5 of the height of the middle rock column from the ground to the top end of the middle rock column, a horizontal two-hole steel sheet 7 is installed and fixed after the guide pipe grouting anchor rod 3 and the hollow grouting anchor rod 1 are installed, the two-hole steel sheet 7 is connected in a positive and negative mode, each steel sheet 7 is connected with two adjacent guide pipe grouting anchor rods 3 or hollow grouting anchor rods 1 on the same horizontal line, the guide pipe grouting anchor rods 3 or the hollow grouting anchor rods 1 on the same horizontal line are connected into a whole after splicing is completed and fixed by a first screw cap 6, and then grouting and concrete spraying are carried out;

(3) the middle part of the middle rock pillar is provided with a prestressed anchor rod 2, the prestressed anchor rod 2 is grouted and horizontally penetrates through the middle rock pillar, and two ends of the prestressed anchor rod 2 are fixed and pre-tightened by a second nut 8;

(4) Inverted arch excavation and second lining construction: after the tunnel body is excavated, inverted arch support is timely carried out, the ring is closed, concrete is timely sprayed to complete secondary lining support, and all construction processes and technical indexes of lining must meet the requirements of design or specification.

Through practical inspection, compared with the conventional reinforcing vertical displacement, the reinforcing structure and the construction method of the small-clear-distance tunnel have the advantages that the vertical displacement is reduced by about 80%, and the horizontal displacement is reduced by about 20%; the vertical stress is reduced by 5 to 10 percent, and the reinforcing effect is very obvious; the collapse of the tunnel or the cracking of the circumferential surrounding rock 5 lining of the tunnel is obviously reduced.

In the description of the present invention, it should be noted that the terms "top", "bottom", "upper", "lower", "horizontal", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.