CN109723465B

CN109723465B - Tube sheet centralizing method for TBM tunnel boring machine

Info

Publication number: CN109723465B
Application number: CN201910207359.9A
Authority: CN
Inventors: 韦猛; 郑明明; 宋宇; 霍宇翔; 温继伟; 李谦
Original assignee: Chengdu Univeristy of Technology
Current assignee: Chengdu Univeristy of Technology
Priority date: 2019-03-19
Filing date: 2019-03-19
Publication date: 2020-08-11
Anticipated expiration: 2039-03-19
Also published as: CN109723465A

Abstract

The invention belongs to the technical field of tunneling, and particularly relates to a tube piece centralizing method for a TBM tunnel boring machine, wherein 3-6 ring tube pieces are provided with a ring of hoses, and each ring of hoses is formed by splicing a plurality of small hoses adapting to the arc length of the tube piece; mounting a small hose on a pipe sheet from a bottom arch, wherein I-shaped steel is arranged in the small hose at the bottom; filling a hose into a gap between an excavation section and a duct piece along with the assembly of the duct piece; and after the pipe pieces of the standard blocks on the two sides are assembled, injecting high-strength quick-setting cement slurry into the small hoses at the bottom arch, simultaneously injecting cement slurry into the small hoses on the two sides, and after the hoses are completely assembled along with the pipe pieces, injecting cement slurry into the small hoses at the adjacent blocks and the top sealing blocks. The invention has the function of correcting and straightening the TBM pipe piece, can quantitatively calculate the filling amount of each unit through the separation of the hose consolidation body, and reduces the procedures of deflating and grouting the inflatable grout stop pipe.

Description

Tube sheet centralizing method for TBM tunnel boring machine

Technical Field

The invention belongs to the technical field of tunneling, and particularly relates to a tube sheet centralizing method for a TBM (tunnel boring machine).

Background

Tunnel Boring Machines (TBMs) have been widely used in Tunnel construction due to their advantages of fast Boring speed, high safety, and the like. TBM has many important construction processes to ensure construction quality and safety. Wherein, pea gravel backfilling and grouting are an important link in TBM construction.

A large number of engineering practices prove that the pea gravel backfilling and grouting process has a plurality of problems, and the most prominent one is that the grouting amount of cement paste after the pipe is abnormal. In the construction process, the excavation diameter of the cutter head is larger than the diameter of the segment, so that when the cutter head exerts a reaction force on the segment, the segment can generate a swinging effect in the hole wall, and a best-effort area is formed between the segment and the excavation section. The swinging of the duct piece causes the difficulty in pouring pea stones due to the fact that the duct piece is locally attached to the wall of the hole, and a cavity is formed. The cavity causes the increase of the grouting amount of cement paste, causes the over-grouting amount to be far larger than the design, and influences the subsequent grouting effect, thereby greatly reducing the support quality.

For example, the construction method [ P ] of the Liulimna full-face heading machine: CN1166852C, 2004-09-15 technical solution includes: a process for cutting rock and lining segments, wherein: it also includes the segment water stop and the bean stone back filling and cement slurry pouring process; the segment water stopping process comprises the following steps: butting the prefabricated reinforced concrete segments according to the design requirement; placing the filling strips on the butt joints at the bottoms of the filling grooves formed between the pipe pieces; embedding the plastic water-stopping material into the filling groove until the plastic water-stopping material is filled; wedging an iron wedge from the top of the filling groove to compress the plastic water stop material; backfilling a gap butted with the surfaces of the segments with high-strength cement mortar, and configuring a plurality of lead wires; when pea gravel is backfilled between the surrounding rock and the pipe pieces and cement slurry is poured, a part of the cement slurry is poured into a butt joint seam between the two pipe pieces; the process for backfilling the pea gravel and pouring cement slurry comprises the following steps: segmenting the periphery of the installed duct piece according to 12-20 meters, and arranging a rubber hose at the periphery of the segmented duct piece in an annular manner; filling gas with the pressure of 0.2MPa into the rubber hose to enable the rubber hose to expand and tightly press the rock wall and the duct piece; then, backfilling pea stones on the periphery of the segmented duct piece; grouting cement paste; and finally, after the cement slurry is solidified, deflating the rubber hose and injecting the cement slurry. Thereby achieving the purposes of segment water stop and bean particle stone segmented backfill.

This technique utilizes to aerify and ends the thick liquid pipe and carry out the segmentation to the section of jurisdiction periphery, can discover that, aerify the whole that ring and section of jurisdiction formed, because the atmospheric pressure intensity in the gas tube is not big, the axial thrust that produces when the unbalancing TBM cuts to a certain extent, can't reach fixed section of jurisdiction, the effect of just righting. Simultaneously, also just because aerify and end thick liquid pipe atmospheric pressure intensity not enough, section of jurisdiction self gravity is big, the whole gravity of section of jurisdiction self can all transmit the bottom aerify and end the thick liquid pipe on, though aerify and end the thick liquid pipe and can satisfy certain requirement on compressive strength, guarantee the leakproofness, but self must be compressed, the section of jurisdiction centre of a circle also is not concentric with the section centre of a circle, in the great interval of axial thrust, very nearly district is formed very probably, cause the pea grain stone backfill volume to reduce, the grout pouring volume increases. In addition, in the place that needs to turn round in the TBM orbit design, the inflation grout stopping pipe of the lateral wall of turning department can be extruded to a component of TBM axial thrust, make inflation grout stopping pipe take place the compression, because the inflation grout stopping pipe just aerify sealed to it after setting up, the inflation pipe of this lateral wall side takes place the compression, the section of jurisdiction takes place certain displacement, the inflation pipe of another lateral wall is changed into and is produced certain clearance between the cliff from the state of hugging closely the cliff, make and can produce the running thick liquid when grouting in this district section, increase the grout perfusion volume. In addition, the distance between the inflatable grout stopping pipes is too large, so that the requirement of resisting axial reverse thrust cannot be met. Therefore, the technology has the following defects: (1) the air pressure strength can not meet the requirement of ensuring straightening, and a best-effort area can be formed in the construction process, so that the grouting amount is increased. (2) After the pea gravel is backfilled, the inflatable grout stopping pipe is deflated and then backfilled, and the construction steps are added.

The inverted arch support component [ P ] suitable for shield type TBM tunnel prefabricated segment lining structure is as follows: CN108005680A, 2018-05-08 technical solution includes: under the prerequisite that does not weaken section of jurisdiction structural performance, can effectively solve the lining cutting section of jurisdiction and deviate from the shield tail problem of sinking naturally, improve the cyclization quality of section of jurisdiction by a wide margin, can also make things convenient for section of jurisdiction installation, guarantee structural waterproof performance simultaneously, characterized by it includes: the threaded sleeve is arranged in the outer side structure of the prefabricated segment according to the assembly point position in an enveloping manner; the inverted arch supporting members are symmetrically arranged on the outer side of the lower portion of the inverted arch, and are provided with inverted arch supporting legs and supporting screw rods, and the supporting screw rods are detachably connected with the threaded sleeves in a threaded mode. In the implementation process, 4 rows of 8 total threaded sleeves are arranged according to the prefabricated pipe pieces of the bottom arch and the two inverted arches in an assembling point enveloping mode, so that 2 rows of 4 inverted arch supporting members in installation are symmetrically arranged along the vertical center line of the pipe pieces. Wherein, the screw sleeve should be pre-buried in prefabricated lining segment production process, and screw sleeve port portion should carry out interim shutoff in order to avoid the section of jurisdiction to pour the in-process by cement mortar jam, chisels the shutoff after prefabricated section of jurisdiction completion.

This technique is at the in-process of section of jurisdiction installation, through the supporting role of screw sleeve and inverted arch supporting member, prevents the nature of section of jurisdiction and sinks, but can discover that the member through the installation can't form the inclosed space of multistage, can't realize that the segmentation of pea gravel is backfilled. In addition, because this group of component can bear intensity have certain restriction, need every ring section of jurisdiction all to install this component, just can bear the section of jurisdiction dead weight, simultaneously because the difference of section of jurisdiction concatenation form, this group of component has two kinds of forms when structural design, increases the construction degree of difficulty.

Disclosure of Invention

The invention provides a tube sheet centralizing method for a TBM tunnel boring machine, which is used for centralizing a tube sheet, mainly limiting the vertical displacement of the tube sheet and ensuring that the circle center of the tube sheet is concentric with the circle center of an excavated section.

The specific technical scheme is as follows:

the tube sheet centralizing method of the TBM tunnel boring machine comprises the following steps:

A. the interval for installing the pipe piece is reasonably segmented, a ring of hoses can be arranged and installed in 3-6 ring pipe pieces, and each ring of hoses is formed by jointly splicing a plurality of small hoses adapting to the arc length of the pipe piece;

B. on a duct piece needing to be provided with a hose, a small hose is arranged on the duct piece from a bottom arch, I-shaped steel is arranged in the small hose at the bottom, the I-shaped steel in the small hose at the bottom is used for filling a gap between an excavation section and the duct piece, and the effect of supporting the duct piece at the upper part is achieved;

C. continuously installing the small hoses on the duct pieces according to the mounting sequence of the duct pieces, and filling the hoses into gaps between the excavation sections and the duct pieces along with the assembly of the duct pieces;

D. after the standard block duct pieces on the two sides are assembled, injecting high-strength quick-setting cement slurry into the small hose at the bottom arch, and plugging the grouting hole after the injection is finished; and then, cement slurry is poured into the small hoses on the two sides, so that the symmetry is ensured as much as possible.

E. And continuously assembling the duct piece and the hose, grouting into the small hoses at the adjacent block and the top sealing block after the hose is completely assembled along with the duct piece, and plugging grouting holes after grouting is finished.

The tube sheet centralizing method of the TBM tunnel boring machine provided by the invention has the function of maintaining the alignment of the TBM tube sheet, and avoids the formation of a close region between the tube sheet and an excavated section, which causes the decrease of pea gravel backfill amount and the increase of grouting amount. In addition, the segment interval is artificially divided into a plurality of independent intervals by the separation of the hose consolidation body, the segmental backfilling of the pea gravel is guaranteed, the pouring amount of each unit can be quantitatively calculated, and the abnormal condition of the pouring amount caused by other factors can be considered and analyzed if the pouring amount is far larger than the design value. Meanwhile, due to the fact that the distance between the hoses is not long, if the abnormal grouting amount condition is found in the interval, the abnormal grouting amount is caused by the fact that the problem occurs at a certain position or a certain small section, and therefore the problem is solved conveniently and specifically. In addition, because the installed hose has high strength after cement slurry is poured into the hose, the hose does not need to be taken out, the procedures of air discharging and grouting of the inflatable grout stopping pipe are reduced, and the time cost is saved to a certain extent.

Drawings

FIG. 1 is a schematic view of a vertical displacement of a segment;

FIG. 2 is a schematic view of the bending displacement of a beam;

FIG. 3 is a schematic diagram of a statically indeterminate structure;

FIG. 4 is a cross-sectional view of the x-direction projection of a section of the present embodiment after taking corrective measures;

FIG. 5 is a schematic cross-sectional view of the small hose of the present embodiment;

FIG. 6a is a schematic view of segment A centering;

FIG. 6b is a cross-sectional view of the small hose with segment A centered;

FIG. 7a is a schematic structural view of a segment A rotating by a certain angle;

FIG. 7b is a cross-sectional view of the small hose with the segment rotated at a certain angle;

FIG. 8 is a schematic view of the splicing of segments;

FIG. 9 is a detailed view of the center area of the grouting holes;

FIG. 10 is a schematic view of the pipe embedment and hose connection of the present embodiment;

fig. 11 is a perspective view of the present embodiment after the hose is installed.

Detailed Description

The specific technical scheme of the invention is described by combining the embodiment.

In the TBM tunneling process, a gap exists between the duct piece and the excavation section, and the duct piece is vertically displaced due to the action of the dead weight and other vertical forces, so that the duct piece is not concentric with the excavation section, as shown in figure 1. Under the action of axial reverse thrust generated by the TBM, the radial displacement of the duct piece is caused due to the eccentric relation between the action position of the axial reverse thrust and the circle center of the section, and a very close region is generated. Therefore, the core for righting the duct piece mainly limits the vertical displacement of the duct piece and ensures that the circle center of the duct piece is concentric with the circle center of an excavation section.

Through to section of jurisdiction periphery installation hose, carry out the slip casting to it again, utilize consolidation body intensity in the hose to resist the section of jurisdiction righting method of vertical effort such as section of jurisdiction dead weight, limit the vertical displacement of section of jurisdiction, guarantee that the section of jurisdiction centre of a circle is concentric with excavation section centre of a circle, under the effect of axial thrust, alright prevent the production in extremely close region. Meanwhile, the sealing performance of the subsection interval is also ensured, the subsection backfill of the pea gravel is realized, and the pouring amount of cement paste is ensured.

Under the prerequisite of not considering soil or country rock around the section of jurisdiction to section of jurisdiction effect and connecting bolt effect between the section of jurisdiction, can simplify the atress of a certain section of jurisdiction into the atress problem of roof beam, to the required requirement of this problem, the bending stiffness of main analysis roof beam.

In the segment region filled with pea stones and unfilled with pea stones, the segment in this region can be regarded as a cantilever beam model, wherein the self-weight and other vertical forces of the segment can be converted into distributed forces acting on the cantilever beam, so as to discuss the bending displacement of the beam, as shown in fig. 2.

According to the angle of rotation (theta) and maximum deflection (omega) of uniformly distributed load acting on cantilever beam_max) Calculating the formula:

wherein: q-uniformly distributing load; l-beam length; e-modulus of elasticity; i-moment of inertia; EI-bending stiffness

Through the formula, the corner of the beam is in direct proportion to the third power of the length of the beam, and the deflection of the beam is in direct proportion to the fourth power of the length of the beam. Therefore, along with the continuous concatenation of section of jurisdiction, also be the process that the cantilever beam length constantly increases that is exactly, the corner and the maximum deflection of cantilever beam also can increase thereupon this moment, cause great displacement. This is the reason why the segment sinks when the straightening method is not adopted.

Therefore, the corner and the maximum deflection of the beam are reduced, and the length of the beam can be reduced, the moment of inertia can be increased or the rigidity of the beam can be increased under the condition that the external uniform load is constant. It can be found that, when carrying out the section of jurisdiction concatenation, the bending stiffness of section of jurisdiction is unchangeable, and the cross sectional shape of section of jurisdiction is unchangeable simultaneously, and moment of inertia is unchangeable yet. And the length of the duct piece is continuously increased along with the assembly. Therefore, when the rigidity and the inertia moment are not changed and the length of the beam cannot be reduced, the bending rigidity of the beam is increased by a method of adding the middle support, namely, a statically indeterminate structure is adopted. As shown in fig. 3, the cantilever beam with the statically determinate structure is changed into the statically indeterminate beam with additional constraint, so that the maximum bending moment of the beam can be greatly reduced, and the bending deformation of the beam under the action of external load can be remarkably improved.

Therefore, the core of the centralizing principle of the invention is that the statically determinate structure of the duct piece is changed into the statically indeterminate structure through mounting middle constraint, thereby improving the bending rigidity of the duct piece and achieving the purpose of limiting the vertical displacement of the duct piece.

The specific technical scheme comprises the following steps:

After the slurry in the hose reaches a predetermined strength, the annular consolidation body can be called a centralizing ring, and fig. 4 is a cross-sectional view of the x-direction projection after a certain section of centralizing measure is taken.

The centralizing method adopts a hose with a certain diameter and higher strength (meeting the design strength requirement). In order to enable the hose to reach the designed strength in a short time, a metal strip with a certain diameter is embedded and welded in the hose, and the metal strip forms a certain included angle on the inner wall of the hose; the metal strip can be a steel bar strip or other alloy strips, and grouting is performed after the hose is installed, so that the use requirement is met.

The metal strip installed in the hose has a small diameter or width and a short length, and the inclination angle of the metal strip cannot be too large when the metal strip is welded on the hose due to the hardness and the strength of the metal strip. The metal strips are not connected with each other, a slurry flowing channel is formed, and the slurry flowing channel can adapt to the change of the size of the gap between the pipe piece and the surrounding rock, as shown in fig. 5. In addition, a hose connector is provided at a middle position of the small hose, and will be described later.

In addition, in the hose of whole section of jurisdiction bottom, on the hose structure of basis, need to add in the hose and establish I-steel structure. The I-steel that the arch hose was equipped with, when the grout of pouring into has not had intensity yet, plays the effect of supporting whole section of jurisdiction. In addition, the left-right height difference of the previous ring of pipe pieces is measured by a person needing to measure before the pipe pieces are assembled, if the left height is measured, the next ring of bottom falling blocks correspondingly rotate to the right when the pipe pieces are assembled, and finally the bottom falling blocks are centered and the two ends of the bottom falling blocks are almost as high. Therefore, the arrangement position of the I-shaped steel in the hose at the bottom end has two forms so as to adapt to the change of the relative position of the pipe piece.

When the segment a is centered as shown in fig. 6a, as shown in fig. 6b, two i-shaped steels are arranged in the hose below the segment a, and the placement positions of the two i-shaped steels are longitudinally arranged along the excavation direction; when the segment a needs to rotate a certain angle to the right (or left) due to installation as shown in fig. 7a, only one i-steel is arranged in the hose under the segment a, and as shown in fig. 7B, the hose under the segment B2 (or B1) is also provided with a hose with one i-steel, and the i-steels are all longitudinally arranged along the excavation direction.

In most cases, the bottom block cannot be completely centered, and therefore installation by rotating it at a certain angle to the left or right is often the case. However, no matter whether the bottom block is centered or not, after the standard blocks B1 and B2 are installed, the bottom block and the standard blocks can be firstly grouted due to the sectional sealing property of the hose behind the duct piece and the consideration that the grouting is not carried out after the duct piece is completely installed, so that the bottom has strength as early as possible, and the dead weight of the duct piece on the upper part is shared. The purpose is to reduce the independent bearing of the I-steel on the dead weight pressure of the duct piece, reduce certain difficulty for the material selection and the structural design of the later-stage I-steel, and above all, reduce the manufacturing cost of the I-steel. It should be noted that the height of the i-steel is fixed due to its structural invariance. The height of the I-shaped steel is designed by considering the difference between the TBM excavation section and the pipe piece outer diameter during design. The rock wall is cleaned before installation, and the fixing of the I-shaped steel is facilitated. In addition, if the type of the conventional i-steel is selected according to the height of the i-steel, the engineering requirements may not be met. Parameters such as waist thickness, leg width and the like of the I-steel are reasonably set according to the compression condition of the I-steel.

Regarding the connection part of the hose and the segment, as the segment is spliced from bottom to top in sequence as shown in fig. 8, the hose is not connected to the periphery of the segment as a whole, but is connected to the segment to form a ring.

The first step is as follows: assembling a bottom block, and a second step: assembling the standard blocks; the third step: assembling the adjacent blocks; the fourth step: assembling a bottom sealing block;

each section of hose is pre-arranged on the duct piece, and a ring is formed along with the assembly of the duct piece. To realize the assembly of the hose into a ring along with the installation of the duct piece, the available structure of the duct piece can be considered firstly.

Fig. 9 is a detailed view showing the center area of the grouting hole, and a hose connector is arranged at the center of each section of hose according to the structure of the duct piece, so that the hose connector is connected with the grouting hole at the center of the duct piece. The device has the functions of positioning and grouting a channel into the hose after the installation is finished. When a pipe piece is installed, a pipe embedded part is generally installed at the position of a grouting hole so as to realize post-pipe grouting. Therefore, the connection between the pipe piece and the hose is realized by considering the adjustment of part of the structure of the embedded part of the general grouting hole pipe. The structure adjustment considers that the smooth end of a general grouting hole pipe embedded part is processed with external threads with a certain size and connected with the internal threads of a hose connecting piece, so that the connection and fixation of a grouting channel are realized, and the structure adjustment is shown in figure 10.

The length of the processed pipe embedded part is shorter than that of the processed pipe embedded part so as to adapt to the condition that the hose connecting piece enters the grouting hole to be connected with the pipe embedded part and ensure that the hose and the segment can be attached after connection.

In addition, because the hose has certain gravity, if the hose is fixed only by the connecting device at the central position, the hose can sink due to the gravity of the hose during the installation of the hose, and the joint of the hose and the duct piece can not be realized, so that the contact part of the hose and the duct piece is coated with strong glue, and the hose is fixed on the duct piece.

After the hose is well assembled along with the segment, high-strength quick-setting cement slurry meeting design requirements is injected into the hose through the grouting holes. The consolidation body formed by the cement grout and the reinforcing steel bar or other hard alloy in the pipe should meet the strength requirement of resisting axial reverse thrust and the strength condition that the strength of the consolidation body cannot be smaller than that of the consolidation body formed by the pea gravel and the cement grout.

According to the actual requirement, a centralizing ring can be arranged on the 3-6 rings. Fig. 11 is a projection view of the hose installed in the heading direction.

Claims

The method for righting the tube sheet of the TBM tunnel boring machine is characterized by comprising the following steps:

(1) reasonably segmenting the section for installing the pipe piece, arranging and installing a ring of hoses for 3-6 ring pipe pieces, and splicing several small hoses which are adaptive to the arc length of the pipe piece together to form each ring of hose;

(2) on a duct piece needing to be provided with a hose, a small hose is arranged on the duct piece from a bottom arch, and I-shaped steel is arranged in the small hose at the bottom;

(3) continuously installing the small hoses on the duct pieces according to the mounting sequence of the duct pieces, and filling the hoses into gaps between the excavation sections and the duct pieces along with the assembly of the duct pieces;

(4) after the standard block duct pieces on the two sides are assembled, injecting high-strength quick-setting cement slurry into the small hose at the bottom arch, and plugging the grouting hole after the injection is finished; then, grouting cement slurry into the small hoses on the two sides simultaneously, and ensuring the symmetry as much as possible;

(5) and continuously assembling the duct piece and the hose, grouting into the small hoses at the adjacent block and the top sealing block after the hose is completely assembled along with the duct piece, and plugging grouting holes after grouting is finished.
2. The method of claim 1, wherein the i-section steel in the small hose is arranged longitudinally along the excavation direction.
3. The method of claim 1, wherein the hose is uniformly lined with metal strips, and the metal strips form a certain included angle with the inner wall of the hose.
4. The method of claim 1, wherein a hose connector is provided in the middle of each of the small hoses, the hose connectors being in communication with the grouting holes in the center of the segment.
5. The method of claim 1, wherein the grouting holes in the center of the segment are provided with pipe embedded parts, and the pipe embedded parts are in threaded connection with the hose connectors.