CN112682055B - Small-clear-distance parallel tunnel shield tunneling construction method - Google Patents
Small-clear-distance parallel tunnel shield tunneling construction method Download PDFInfo
- Publication number
- CN112682055B CN112682055B CN202110303311.5A CN202110303311A CN112682055B CN 112682055 B CN112682055 B CN 112682055B CN 202110303311 A CN202110303311 A CN 202110303311A CN 112682055 B CN112682055 B CN 112682055B
- Authority
- CN
- China
- Prior art keywords
- grouting
- tunnel
- slurry
- tunneling construction
- construction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
The invention belongs to the technical field of tunnel shield tunneling construction, and particularly relates to a small-clear-distance parallel tunnel shield tunneling construction method. The method comprises the tunneling construction of a preceding tunnel and the tunneling construction of a following tunnel, wherein the minimum distance between a preceding lining segment and a following lining segment of a small-clear-distance tunnel is transited from 6.7m to 3.9 m; the tunneling construction of the advanced tunnel comprises grouting reinforcement of the advanced lining segment; the tunneling construction of the backward tunnel comprises synchronous grouting, secondary grouting and cement paste supplementary grouting. Compared with ground grouting reinforcement, the construction method reduces the reinforcement land occupation time, can perform in-hole grouting reinforcement at any time, and saves the construction period; after the preceding tunnel is grouted and reinforced, the pipe pieces are fixed, so that the pipe piece displacement is reduced, the adjustment of the following tunnel on construction parameters can be reduced, and the tunneling efficiency is increased; the steel perforated pipe is used for grouting reinforcement, and through the improved and innovative construction method, the reinforcement effect is better, the construction quality is high, and the energy-saving and environment-friendly effects are good.
Description
Technical Field
The invention belongs to the technical field of tunnel shield tunneling construction, and particularly relates to a small-clear-distance parallel tunnel shield tunneling construction method.
Background
With the wide application of the shield tunnel construction technology in subway construction, the shield construction technology is mature day by day, the shield tunnel construction is adopted increasingly, especially with the increasingly severe traffic pressure in the major cities in China for relieving the pressure, the influence of city planning and the existing building space and the removal pressure are limited, the parallel construction of small clear distance tunnels and the shield receiving form tunnels adjacent to the maintenance structure occur at home and abroad, but the small clear distance tunnels are mostly researched in the tunneling process, the parallel tunneling research of the small clear distance (the minimum distance between the parallel tunnel segments is transited from 6.7m to 3.9 m) is less, and the research on the small clear distance in powdery clay, earthy strongly weathered grey quartzite, blocky strongly weathered grey quartzite and fully weathered grey quartzite and the tunneling construction along with the shield is less.
In the shield tunneling construction process of the small clear distance parallel tunnel, the tunneling of the backward tunnel easily disturbs the lining segment of the forward tunnel (referred to as the forward lining segment for short), so that the construction quality cannot be ensured, and the tunneling efficiency is low.
Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to provide a shield tunneling construction method of a small-clear-distance parallel tunnel, which aims to solve the problems that the shield tunneling construction quality of the small-clear-distance parallel tunnel is difficult to guarantee and the construction efficiency is low.
In order to achieve the above purpose, the invention provides the following technical scheme:
a small clear distance parallel tunnel shield tunneling construction method comprises the tunneling construction of a preceding tunnel and the tunneling construction of a following tunnel, wherein the minimum distance between a preceding lining segment and a following lining segment of the small clear distance tunnel is transited from 6.7m to 3.9 m;
the tunneling construction of the advanced tunnel comprises grouting and reinforcing the advanced lining segment, wherein the grouting area is a soil body within 3m of the advanced lining segment, grouting is carried out through a steel floral tube, the steel floral tube is left in the soil body after grouting, and the steel floral tube is driven into the soil body along a grouting hole;
the tunneling construction of the backward tunnel comprises synchronous grouting, secondary grouting and cement paste supplementary grouting.
As an improvement on the construction method, preferably, in the tunneling construction of the advanced tunnel, the steel perforated pipe is formed by splicing three sections, each section of pipe is 1m long, and slurry outlet holes are uniformly formed in the inner pipe wall of the steel perforated pipe.
As an improvement on the construction method, in the tunneling construction of the advanced tunnel, the grouting slurry is preferably single cement slurry, and the water-cement ratio of the single cement slurry is 1: 1.
As an improvement to the construction method, preferably, the grouting amount of each linear meter of a single grouting hole is 0.4-0.6 m for carrying out the high-speed labor cultivation, and the grouting pressure is 0.4-0.8 MPa.
As an improvement of the construction method, preferably, in the tunneling construction of the preceding tunnel, the final pressure of the grouting is 1.0 to 1.5 times of the hydrostatic pressure of the construction section, and after the grouting is finished, the sealing treatment is performed on the grouting hole.
As an improvement on the construction method, preferably, the sealing treatment adopts cement-water-glass two-fluid slurry.
As an improvement on the construction method, more preferably, the cement-water glass double-liquid slurry is prepared by mixing cement slurry and water glass slurry in a volume ratio of 1:1, the mass ratio of water to cement in cement paste is 1:1, the mass ratio of water glass to water in the water glass slurry is 1:1, the baume degree of the water glass is 40.
As an improvement on the construction method, in the tunneling construction of a backward tunnel, the grouting amount of synchronous grouting is 100-120% of the total filling amount.
As an improvement on the construction method, the pressure of the synchronous grouting is preferably 2.0-3.0 bar.
Preferably, the slurry of the synchronous grouting consists of cement, fly ash, bentonite, sand and water.
As an improvement on the construction method, preferably, in the tunneling construction of the backward tunnel, the secondary grouting is performed on the 5 th ring pipe piece out of the shield tail through a hoisting hole positioned on the upper half part of the pipe piece, and the secondary grouting is performed every five rings.
As an improvement on the construction method, preferably, the secondary grouting is injecting double-liquid grouting, and the grouting amount of each ring of the secondary grouting is 0.5-1.0 m3。
As an improvement on the construction method, the pressure of the secondary grouting is preferably 3.0-3.5 bar.
As an improvement to the construction method, preferably, the two-fluid slurry is composed of water glass slurry and cement slurry in a volume ratio of 1:1, and the mass ratio of water glass to water in the water glass slurry is 1:1, the baume degree of the water glass is 40, and the water cement ratio of the cement paste is 1: 1.
as an improvement on the construction method, preferably, the plugging rings are formed after secondary grouting, the supplementary grouting of cement paste is grouting on the lining segment between the plugging rings through a top hoisting hole, and the top hoisting hole is positioned at the upper half part of the lining segment.
As an improvement to the construction method, it is preferable that the cement paste has a water cement ratio of 1: 1.
As an improvement to the construction method, it is preferable that the amount of soil discharged per linear meter or per ring is 70 to 78m in the driving construction of the following tunnel3。
As an improvement on the construction method, preferably, in the tunneling construction of the backward tunnel, the total thrust is 14000-15000 kN, the pressure of an upper soil bin is 1.2-1.4 bar, the tunneling speed is 20-30 mm/min, the rotating speed of a cutter head is 0.8-1.2 rpm, and the torque of the cutter head is 1500-3000 kN.m.
As an improvement on the construction method, the construction stratum is preferably one or two or three of silty clay, earthy strongly weathered tuff quartzite, massive strongly weathered tuff quartzite and fully weathered tuff quartzite.
Has the advantages that: compared with the ground grouting reinforcement, the construction method reduces the reinforcement land occupation time, can perform in-hole grouting reinforcement at any time, and saves the construction period; after the preceding tunnel is grouted and reinforced, the pipe pieces are fixed, so that the pipe piece displacement is reduced, the adjustment of the following tunnel on construction parameters can be reduced, and the tunneling efficiency is increased; the steel perforated pipe is used for grouting reinforcement, and through the improved and innovative construction method, the reinforcement effect is better, the construction quality is high, and the energy-saving and environment-friendly effects are good.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. Wherein:
FIG. 1 is a schematic cross-sectional view of a small clear distance parallel tunnel according to the present invention;
FIG. 2 is a schematic representation of a steel ferrule of the present invention;
fig. 3 is a schematic structural view of the pick tip of the present invention;
FIG. 4 is a schematic view of the arrangement of grouting holes of the leading tunnel according to the present invention;
FIG. 5 is a schematic view of the simultaneous grouting process of the present invention;
FIG. 6 is a schematic view of a secondary grouting process of the present invention;
FIG. 7 is a schematic view of the grouting range of the secondary grouting of the present invention;
FIG. 8 is a schematic illustration of the post-grouting cement paste process of the present invention.
In the figure: 1-a first-row tunnel, 2-a second-row tunnel, 3-a first-row lining pipe piece, 4-a second-row lining pipe piece, 5-a grouting hole, 6-a steel floral tube, 7-a first section, 8-a second section, 9-a third section, 10-a pickaxe tip, 11-a shield machine, 12-a soil body, 13-a plugging ring and 14-a filling reinforcement body.
In FIG. 4, the numbers of the first to sixth are the numbers of the grouting holes;
in fig. 5, 6 and 8, the direction indicated by the arrow is the advancing direction of the shield tunneling machine;
in fig. 7, first to ⑯ are numbers of hoisting holes, and the direction indicated by an arrow is the direction of the ground.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected" and "connected" used herein should be interpreted broadly, and may include, for example, a fixed connection or a detachable connection; they may be directly connected or indirectly connected through intermediate components such as pipes, devices, etc., and the specific meanings of the above terms will be understood by those skilled in the art according to specific situations.
In the invention, the antecedent lining segment is the lining segment of the antecedent tunnel, and correspondingly, the posterior lining segment is the lining segment of the posterior tunnel.
The cross-sectional structure of the small-clear-distance parallel tunnel is schematically shown in fig. 1. The small-clear-distance parallel tunnel comprises a leading tunnel 1 and a trailing tunnel 2. The inside of the advanced tunnel 1 is a leading lining segment 3 formed after the shield machine passes through, and the inside of the backward tunnel 2 is a backward lining segment 4 formed after the shield machine passes through.
During construction of the backward tunnel 2, tunneling parameters are reasonably selected, a three-stage grouting mode is adopted for grouting after the backward lining segment 4, namely synchronous grouting and secondary grouting are carried out to form a plugging ring, cement is additionally injected to form clean slurry, a small amount of multiple grouting modes are adopted, and disturbance to the forward tunnel is reduced. Synchronous grouting of the backward tunnel is performed by using shield machine equipment without grouting through a pipe sheet; and secondary grouting and supplementary grouting cement paste are carried out through the hoisting holes in the duct pieces, and other holes are not additionally arranged, namely the hoisting holes are grouting holes for tertiary grouting of the backward tunnel (the grouting holes all utilize the existing hoisting holes).
The following is a detailed description of the grouting reinforcement of the preceding tunnel and the driving construction of the following tunnel, respectively.
1. Advance tunnel
The tunnel 1 permeates the single-liquid grout of the cement paste into the soil body through the steel perforated pipe 6, so that the physical and mechanical performance indexes of the soil body are effectively improved, and the stability of the soil body is improved. The steel perforated pipe 6 is left in the soil body after grouting, and provides a certain anchoring or anti-sliding effect for the lining segment 3 in advance. The reinforcement of the steel perforated pipe 6 in the preceding tunnel 1 and the propulsion control measure of the following tunnel 2 are combined together, so that the safety and stability coefficient of the small-clear-distance parallel tunnel is effectively improved.
The steel perforated pipe 6 for grouting of the advanced tunnel 1 is generally a seamless steel pipe with the diameter phi of 48mm and the wall thickness of 3mm, and is divided into three sections, namely a first section 7, a second section 8 and a third section 9, as shown in a schematic structural diagram in figure 2, wherein each section of the pipe is 1 meter long. The steel perforated pipe 6 adopts the mode of concatenation during the construction, not only is convenient for transport, also is convenient for put into the slip casting hole 5 with steel perforated pipe 6 in narrow and small space. The inner pipe wall of the steel perforated pipe 6 is evenly provided with a slurry outlet hole with the diameter of 8mm, the bottom of the steel perforated pipe is welded with a joint, and a sealing ring is arranged at the top part close to the third section 9 and is connected with a slurry conveying pipe.
The method for punching and grouting the lining segment 3 in advance comprises the following steps:
(1) preparing a steel perforated pipe 6 grouting machine: pneumatic picks, steel perforated pipes, pick tips, steel drill rods, grouting systems (grouting pipes, ball valves and the like), stirrers, cement, water glass and the like. Wherein, the pick point is a self-made tool for external processing, the specific structure is shown in figure 3, when in use, one end is inserted into the steel perforated pipe 6, and the other end uses the pneumatic pick to drive the steel perforated pipe 6 into the soil body.
(2) When the prior tunnel 1 is constructed, firstly, steel drill rods are used for forming grouting holes 5 in the prior lining pipe pieces 2, and each ring pipe piece is totally provided with 6 grouting holes 5, wherein the grouting holes 5 are sequentially punched through by using steel perforated pipes 6 as shown in the figure 4.
(3) Steel perforated pipes 6 with the diameter of 48 multiplied by 3mm are sequentially driven into the grouting holes 5 by a G20 type pneumatic pick, and the length of the steel perforated pipes is required to extend out of the front lining segment 5 by 3m (namely the drilling depth reaches 3m behind the segment of the front lining segment 3). A leather pad check valve is arranged at one end of the steel perforated pipe 6 entering the soil body, and a ball valve is arranged at one end of the grouting pipe.
(4) And mixing the grouting slurry and the hole sealing slurry, connecting the pipelines, and checking whether the pipelines are smooth or not to ensure that the grouting requirement is met.
The grouting slurry is single cement slurry, and for the slurry concentration, the aim of the grouting engineering is to reinforce the stratum and improve the vertical anti-deformation capability of the stratum, not to block water or bear horizontal ground pressure, so that a quite regular curtain with a certain thickness is not required to be formed in the stratum around the reinforcement, thick slurry is injected to the greatest extent to squeeze and fill a water-containing sand layer, the strength of a stone body is enhanced, and the thick slurry is mainly used as the greatest extent according to the pumpability, the flowability and the cementation of the slurry under the condition that the slurry can be pressed into the stratum. The water-cement ratio of the single-fluid cement paste of the cement paste is 1: 1.
The hole sealing slurry is cement-water glass double-liquid slurry, wherein the cement-water glass double-liquid slurry is prepared from cement slurry and water glass slurry in a volume ratio of 1:1, the mass ratio of water to cement in cement paste is 1:1, the mass ratio of water glass to water in the water glass slurry is 1:1, the baume degree of the water glass is 40.
(5) Deep grouting after the duct piece is carried out through a ball valve arranged on the steel perforated pipe, and grouting is carried out by adopting an QYB03 type grouting pump until the soil body outside the lining duct piece 3 is stabilized in advance and then grouting is finished. The grouting material adopts single grout of cement paste; the water cement ratio of the cement paste is initially 1:1, and the concentration of the cement paste is adjusted according to the stratum condition. The grouting amount per linear meter (a ring pipe piece width is 1.5 meters, and 2/3 of the width of the single ring pipe piece is about per linear meter) of the single grouting hole is 0.4-0.6 m (such as 0.4m, 0.45m, 0.50m, 0.55m, and 0.6 m) for cultivation) (adjustable according to the overbreak condition), the pressure control is mainly used (the purpose is to inject the slurry), and the grouting pressure is 0.4-0.8 MPa (such as 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, and 0.8 MPa). And optimizing grouting parameters according to the monitoring feedback information in the grouting construction process.
(6) According to hydrogeological conditions and the past grouting construction experience, the final pressure of grouting is generally 1.0-1.5 times of the hydrostatic pressure of a grouting section (the final pressure is controlled to ensure the grouting quality, such as 1.0 time, 1.1 time, 1.2 times, 1.3 times, 1.4 times and 1.5 times), the maximum pressure of the orifice of a grouting hole in the construction is 0.3-0.4 MPa (such as 0.30MPa, 0.32MPa, 0.34MPa, 0.36MPa and 0.38 MPa) by combining other factors, and the specific final pressure of each section is adjusted according to the actual grouting condition.
(7) And after grouting is finished, adopting cement-water-glass double-liquid slurry to carry out hole sealing treatment on the grouting hole, and finishing grouting.
2. Back tunnel
The influence of the backward tunnel 2 on the forward tunnel 1 is mainly the influence of soil disturbance on the forward tunnel 1 in the tunneling process, the pressure of an upper soil bin is adjusted according to the geology of a construction section, the thickness of covering soil, the condition of the completed tunnel and the ground surface monitoring result in the propelling process of the shield machine, the propelling speed is kept relatively stable, and the correction amount of each time is well controlled. The rotation speed of the cutter head is reduced, the thrust is reduced, the disturbance to the soil body is reduced as much as possible, and the influence on the preceding tunnel is avoided.
And the grouting behind the backward lining segment 4 adopts a three-stage grouting mode, the segment is fully filled, the displacement of the segment is prevented, and the deviation of the construction axis and the design axis and the stratum change are controlled within an allowable range. Wherein, the grouting amount of the synchronous grouting needs to be adjusted in time according to the propelling speed, the slag discharge amount and the ground surface monitoring data.
The main control measures in the backward tunnel tunneling construction process are as follows:
(1) the propelling speed of the shield machine is strictly controlled, when the shield is constructed in a small clear distance section, the propelling speed is controlled to be 20-30 mm/min (such as 20mm/min, 22mm/min, 24mm/min, 26mm/min, 28mm/min and 30 mm/min), if the propelling is too fast, the extrusion effect of the opening section of the cutter head on the stratum is relatively obvious, in order to reduce the disturbance on the surrounding soil body, the propelling needs to be slowed down and continued, and the long-time delay on the way is avoided.
(2) The upper soil pressure is controlled according to the stratum and the underground water level burial depth, the pressure of an upper soil bin of a small-clearance construction section is controlled to be 1.2-1.4 bar (such as 1.2bar, 1.25bar, 1.3bar, 1.35bar and 1.4 bar), and disturbance of the super-excavation on a bottom layer is avoided.
(3) The rotation speed of the cutter head is reduced to avoid large disturbance to the stratum, the rotation speed of the cutter head is controlled to be 0.8-1.2 rpm (such as 0.8rpm, 0.9rpm, 1.0rpm, 1.1rpm and 1.2 rpm), the torque of the cutter head is 1500-3000 kN.m (such as 1500 kN.m, 1600 kN.m, 1700 kN.m, 1800 kN.m, 1900 kN.m, 2000 kN.m, 2100 kN.m, 2200 kN.m, 2300 kN.m, 2400 kN.m, 2500 kN.m, 2600 kN.m, 2700 kN.m, 2800 kN.m and 2900 kN.m).
(4) In order to avoid the influence of equipment failure on the tunneling efficiency, a 24h linkage mechanism is established in the department of project, each shield is provided with a main driver, two machine repairers are responsible for daily maintenance work of the shield machine, and the ground maintenance team is provided with 8 (including electricians) 24h linkage mechanisms to ensure the normal operation of the shield machine, a gantry crane and an accumulator car, so that the shield machine in the construction of a subsequent tunnel passes through the tunnel quickly and uniformly to influence the range of a previous tunnel.
(5) And the monitoring of the formed advanced tunnel and the ground surface is enhanced when the backward tunnel shield is tunneled, and the machine is stopped in time for processing when an emergency occurs.
The grouting construction of the backward tunnel has the problems that the thickness of the soil body clamped between the backward tunnel and the forward tunnel is small, the excavation disturbance influence is serious, the stratum bearing capacity is insufficient, the posture of the backward construction tunnel (corresponding to the backward tunnel) is difficult to control, the finished tunnel (namely the forward tunnel) and the enclosure structure are easily influenced, and the displacement of a segment, the displacement of the tunnel, the loosening of bolts, the deformation of the enclosure structure and the like are caused. In order to ensure the construction safety, the construction of the backward tunnel adopts a construction process of three-stage grouting. The grouting construction process of the backward tunnel specifically comprises the following steps:
(1) synchronous grouting
According to the actual construction of the shield tunnel, the diameter of a shield machine blade is generally larger than the outer diameter of a lining segment, when the lining segment is separated from a shield tail, a certain gap (annular shape) exists between a soil body and the lining segment, and the thickness is usually 8-20 cm (such as 8cm, 10cm, 12cm, 14cm, 16cm, 18cm and 20 cm).
As shown in fig. 5, the synchronous grouting is to inject grout with short initial setting time into a gap between a back lining segment 4 and a soil body 12 while a shield machine 11 is propelled forward, and the pressure of the synchronous grouting is 2.0-3.0 bar (the synchronous grouting does not pass through grouting holes, such as 2.0bar, 2.2bar, 2.4bar, 2.6bar, 2.8bar, and 3.0 bar). The grouting amount is 100-120% of the total filling amount (the total filling amount is the total volume of the slurry required for filling the gap, such as 100%, 105%, 110%, 115%, and 120%), and the general tunnel diameter is 6.98m, so that the grouting amount per ring is 5.5-6.5 m for carrying out the year (such as 5.5m for carrying out the year, 5.7m for carrying out the year, 5.9m for carrying out the year, 6.1m for carrying out the year, 6.3m for carrying out the year, and 6.5m for carrying out the year). The injected slurry plays a role in solidifying soil in the excavated space, and the upward floating of the duct piece is effectively reduced (the synchronous grouting amount is dynamically adjusted according to the actual upward floating condition on site). The initial setting time of the slurry for synchronous grouting is controlled to be 4 hours, the final setting time of the slurry for synchronous grouting is controlled to be about 8 hours, and the slurry for synchronous grouting is prepared from cement, fly ash, bentonite, sand and water according to the mass ratio of 180: 315: 70: 675: 400. A schematic diagram of the simultaneous grouting process is shown in fig. 5.
(2) Secondary grouting
As shown in fig. 6 and 7, in the range of 3-13 points of the backward lining segment (i.e. the upper half part of the backward lining segment except for the capping block) of the fifth ring of the shield tail of the shield machine 11, secondary grouting is performed by using the hoisting hole on the segment to form a plugging ring 13, secondary grouting is performed every five rings, and the pressure of the secondary grouting is 3.0-3.5 bar (for example, 3.0bar, 3.1bar, 3.2bar, 3.3bar, 3.4bar, and 3.5 bar). The slurry for secondary grouting is double-liquid slurry and is formed by mixing water glass slurry and cement slurry according to the volume ratio of 1:1, wherein the mass ratio of water glass to water in the water glass slurry is 1:1, the baume degree of the water glass is 40, and the water cement ratio of the cement paste is 1: 1. the double-fluid slurry has the following functions: firstly, double-liquid slurry is solidified and cyclized between a backward lining segment and an excavated soil body surface, so that the upward floating and horizontal deformation displacement of the backward lining segment are effectively restrained; and forming a partition wall, which is favorable for the filling effect of the subsequent cement paste filling.
(3) Cement paste for filling
As shown in fig. 8, at the position of the middle ring lining segment between the plugging rings 13 formed by the secondary grouting, cement paste is additionally injected after the segment is formed by using the top hoisting hole (the top hoisting hole is positioned at the upper half part of the lining segment), and the filling reinforcing body 14 is formed except for the top sealing blocks. The mass ratio of water to cement in the cement paste is 1:1, controlling the initial setting time to be 3h and controlling the final setting time to be 7 h. And finally filling the cavity after the pipe piece is built by filling cement paste.
It can be understood that the positions of the pipe pieces can rotate when the pipe pieces are assembled, one position of each ring pipe piece is positioned, and the top sealing blocks are wedge-shaped blocks, so that the deformation of the top sealing blocks can be caused due to the overlarge grouting pressure, and secondary grouting and cement supplementary grouting are not performed by the aid of the top sealing blocks.
The optimization process of the process parameters of the backward tunnel in the invention is further explained by taking the whole process of performing small-clear-distance parallel tunnel shield tunneling construction between the shield regions of the Shenzhen urban rail transit 14 # line project Shenhe station and the Shenlongstation as an example.
1. Early stage parameter setting
According to the construction experience of the trial tunneling section, when the small-clearance section is constructed, the tunneling parameters are set as shown in the following table 1.
TABLE 1 pseudo-setting table of tunneling parameters of small-clear-distance trial tunneling stratum backward tunnel
Note: in table 1: the grouting amount and the soil discharging amount refer to the grouting amount and the soil discharging amount of each ring; the soil bin pressure refers to the upper soil bin pressure. Tables 2 and 3 are the same as those in the above description and will not be described again.
The formation designations in table 1 refer to:
1 #: powdery clay.
2 #: earthy strongly weathered pozzolanic quartzite.
3 #: massive strongly weathered pozzolanic quartzite.
4 #: completely weathered pozzolanic quartzite.
The strata classification divides the strata of the line according to the specifications of geotechnical engineering investigation Specification (GB 50021-2001) (2009 edition), urban rail transit geotechnical engineering investigation Specification (GB 50307-2012), engineering classification standard of soil (GB/T50145-2007) and the like.
The layers of the construction interval of the embodiment are divided into three main categories: soft soil, soft top and hard bottom, and rock stratum. Wherein, soft soil stratum contains: the high-strength concrete wall structure comprises powdery clay, completely weathered tuff quartzite and soil-like strongly weathered tuff quartzite (the layers have no strength), wherein the medium weathered tuff quartzite with high strength belongs to rock layers, the upper part in the section is a soft soil layer, the lower part in the interface of the change of the tunnel strata is a rock layer, and the rock layers in the range belong to the upper part and the lower part.
The following is a detailed description of the various formations described above:
powdery clay: mainly takes brown yellow, brown red and red brown as main materials, and is plastic to hard plastic and mainly formed by weathering residual accumulation of tufaceous quartzite. The standard penetration hammering number is 8-39 strokes, and the average hammering number is 23.3 strokes.
Earthy strongly weathered pozzolanic quartzite: yellow brown, brown yellow and dark brown, most of the tissue structures are destroyed, the tissue structures are easy to soften when meeting water, and the strength is reduced. The actual measured standard penetration number is 60-100 strokes, and the average penetration number is 77.3 strokes.
Massive strongly weathered pozzolanic quartzite: brownish yellow, brownish gray and grayish yellow, stone efflorescence is severe, joint cracks develop very well, and a large number of stroke-induced rock masses are clamped in the local part. Rock blows are brittle and part of the hand can break. The rock mass is extremely soft rock-soft rock, the rock mass is in a crushed block shape and extremely crushed, and the basic quality grade of the rock mass is V grade.
Fully weathered pozzolanic quartzite: the structure of the original rock tissue is basically destroyed but can be identified, besides quartz, other minerals are weathered into cohesive soil, the weathering is not uniform, and strong weathering rock blocks are often sandwiched. The actual measured standard penetration impact number is 40-68 impacts, and the average impact is 49.0 impacts.
Aiming at the characteristics that the stratum in the shield interval of the Bao lotus station-Baolong station is mainly silty clay (2 #), earthy strongly weathered tufa quartzite (3 #), massive strongly weathered tufa quartzite (4 #), and completely weathered tufa quartzite (5 #), the trial excavation parameters of the construction section are preliminarily determined according to the proposed parameters in the table 1, and the specific construction parameters are shown in the table 2.
Table 2 small clear distance trial excavation stratum backward tunneling parameter drawing-up table
Note: the side pass phase 896-900 loop in the table is receive.
Finding out in the trial tunneling process:
(1) according to the actual measurement segment posture display, the tunnel segment 816 and 839 rings are displaced to different degrees.
(2) In the process of tunneling the backward tunnel, the 771-.
(3) When the enclosure structure of the preceding tunnel is penetrated at the side of the following tunnel, the 879-895-ring enclosure structure has slight water leakage phenomenon.
The optimization of the tunneling parameters in the construction process specifically comprises the following steps:
(1) according to the posture display of the manually measured segment, in the process of tunneling the 816-839 ring of the backward tunnel (left line), the relative position of the forward tunnel (right line) generates the leftward displacement phenomenon of different degrees, and the phenomenon caused by overlarge thrust in the process of tunneling the backward tunnel can be considered; and in the subsequent tunneling process, the thrust is reduced, the total thrust is controlled to be 8000-15000 kN, and the synchronous grouting pressure is reduced and controlled to be 2.0-3.0 bar.
(2) Aiming at the gushing condition of the backward tunnel 771-773 ring and the 852-875 ring during the tunneling in the soft soil stratum, the following control measures are set for the tunneling in the soft soil stratum.
Firstly, when a section with large water amount is tunneled, a spiral conveyor double-gate control is adopted, and a suspending agent is filled. Meanwhile, the secondary grouting equipment matched with the shield machine is utilized to perform timely grouting, a continuous plugging ring is formed behind the back of the duct piece, a water catchment channel is prevented from being formed around the duct piece, and the gushing is avoided.
And secondly, if the gushing phenomenon occurs, immediately closing a gate of the spiral conveyor, properly tunneling forwards to establish soil pressure balance in the soil bin, and uniformly stirring the soil body in the soil bin through the rotation of the cutter head. Then the screw conveyer is slowly rotated, the gate is slowly opened, the opening degree is 30%, soil is excavated while digging, and the pressure in the soil bin is kept stable all the time.
Thirdly, high-concentration bentonite is added into the soil bin, the workability of soil in the soil bin is improved, particles and slurry in the soil are integrated and continuously discharged from the screw conveyor, and gushing is avoided.
(3) Aiming at the water leakage phenomenon of the enclosure structure in the process of the left line side penetrating through the enclosure structure, the analysis can be that the rotation speed of the cutter head is too high, the synchronous grouting pressure and the secondary grouting pressure are too high to cause great disturbance to the soil body, and the water in the soil body is extruded to the enclosure structure to cause the water leakage condition to occur due to the overlarge pressure of the upper soil bin. The following parameter adjustments were made.
Firstly, in order to reduce disturbance to an enclosure structure, properly reduce the rotating speed of a cutter head, synchronous grouting pressure and secondary grouting pressure and reduce stratum disturbance, the rotating speed of the cutter head selected in the tunneling process in the subsequent side-penetrating stage is 0.8-1.2 rpm, the synchronous grouting pressure is controlled to be 2.5-3.0 bar, and the secondary grouting pressure is controlled to be 3.0-4.0 bar.
Secondly, combining theoretical pressure calculation and actual ground settlement feedback, controlling the pressure of the upper soil bin to be 1.0-1.2 bar, performing secondary grouting in time, monitoring the ground surface, and processing the found problems in time.
Controlling the tunneling speed, the total thrust and the cutter head torque: according to construction experience, the propelling speed of the tunneling in the stratum is not suitable to be too large, and the corresponding propelling force and torque control are not suitable to be too large. The maximum value of the cutter head torque is controlled within 2000 kN.m, the tunneling speed is controlled to be about 20mm/min, and the total thrust is 10000-12000 kN.
The adjusted tunneling parameters are shown in table 3.
Table 3 small clear distance trial excavation stratum backward tunneling parameter adjusting table
The method influences the rule, the conditions such as surface subsidence and the like and related rules by the internal force and displacement of the small-clear-distance advanced lining segment; the disturbance influence rule of the tunneling parameters such as the upper soil bin pressure, the synchronous grouting pressure, the secondary grouting pressure, the soil discharge amount, the shield tunneling machine thrust and the like of the backward tunnel on the lining structure of the small-clear-distance forward tunnel is researched, so that the proper shield tunneling parameters are determined.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A shield tunneling construction method of a small-clear-distance parallel tunnel is characterized by comprising the steps of tunneling construction of a front tunnel and tunneling construction of a back tunnel, wherein the minimum distance between a front lining segment and a back lining segment of the small-clear-distance parallel tunnel is changed from 6.7m to 3.9 m; the small clear distance parallel tunnel is a horizontal parallel tunnel;
the construction stratum is one or two or three of silty clay, earthy strongly weathered tuff quartzite, massive strongly weathered tuff quartzite and completely weathered tuff quartzite;
the driving construction of the advanced tunnel comprises grouting and reinforcing the advanced lining segment, the grouting area is a soil body within 3m of the advanced lining segment, the grouting is carried out through a steel floral tube, the steel floral tube is left in the soil body after the grouting, and the steel floral tube is driven into the soil body along a grouting hole; the grouting pressure is 0.4-0.8 MPa;
the tunneling construction of the backward tunnel comprises synchronous grouting, secondary grouting and cement paste supplementary grouting;
the grouting amount of the synchronous grouting is 100-120% of the total filling amount;
the secondary grouting is performed on the 5 th ring pipe piece out of the shield tail through a hoisting hole positioned on the upper half part of the pipe piece, and the secondary grouting is performed every five rings;
the secondary grouting is injecting double-liquid slurry, and the grouting amount of each ring of the secondary grouting is 0.5-1.0 m3；
The pressure of the secondary grouting is 3.0-3.5 bar;
in the tunneling construction of the backward tunnel, the soil output per linear meter or per ring is 70-78 m3(ii) a The pressure of the upper soil bin is 1.2-1.4 bar, and the tunneling speed is 20-30 mm/min;
and forming plugging rings after secondary grouting, wherein the post-grouting cement paste is formed by grouting on the lining segment between the plugging rings through a top hoisting hole, and the top hoisting hole is positioned at the upper half part of the lining segment.
2. The small clear space parallel tunnel shield tunneling construction method according to claim 1, wherein in the tunneling construction of the advanced tunnel, the steel perforated pipe is formed by splicing three sections, each section is 1m long, and slurry outlet holes are uniformly formed in the inner pipe wall of the steel perforated pipe.
3. The small-clear-distance parallel tunnel shield tunneling construction method according to claim 1, characterized in that in the tunneling construction of the advanced tunnel, the grouting slurry is cement slurry single liquid slurry, and the water cement ratio of the cement slurry single liquid slurry is 1: 1;
and carrying out the high-speed dry-cast high-speed thin.
4. The small-clearance parallel tunnel shield tunneling construction method according to claim 1, wherein in the tunneling construction of the leading tunnel, the final pressure of the grouting is 1.0-1.5 times of the hydrostatic pressure of a construction section, and after the grouting is finished, the grouting holes are subjected to hole sealing treatment;
the hole sealing treatment adopts water-slurry-glass double-liquid slurry;
the cement paste water glass double-liquid slurry is prepared from cement slurry and water glass slurry in a volume ratio of 1:1, the mass ratio of water to cement in the cement paste is 1:1, the mass ratio of water glass to water in the water glass slurry is 1:1, the Baume degree of the water glass is 40.
5. The small-clearance parallel tunnel shield tunneling construction method according to claim 1, wherein the pressure of the synchronous grouting is 2.0-3.0 bar;
the slurry for synchronous grouting consists of cement, fly ash, bentonite, sand and water.
6. The small clear distance parallel tunnel shield tunneling construction method according to claim 1, characterized in that in the tunneling construction of the backward tunnel, the double-liquid slurry is composed of water glass slurry and cement slurry in a volume ratio of 1:1, and the mass ratio of water glass to water in the water glass slurry is 1:1, the baume degree of the water glass is 40, and the water cement ratio of the cement paste is 1: 1.
7. the small-clearance parallel tunnel shield tunneling construction method according to claim 1, wherein the cement paste has a water-cement ratio of 1: 1.
8. The small-clearance parallel tunnel shield tunneling construction method according to claim 1, wherein in the tunneling construction of the backward tunnel, the total thrust is 14000 to 15000kN, the cutter head rotation speed is 0.8 to 1.2rpm, and the cutter head torque is 1500 to 3000kN · m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110303311.5A CN112682055B (en) | 2021-03-22 | 2021-03-22 | Small-clear-distance parallel tunnel shield tunneling construction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110303311.5A CN112682055B (en) | 2021-03-22 | 2021-03-22 | Small-clear-distance parallel tunnel shield tunneling construction method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112682055A CN112682055A (en) | 2021-04-20 |
| CN112682055B true CN112682055B (en) | 2021-07-09 |
Family
ID=75455742
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110303311.5A Active CN112682055B (en) | 2021-03-22 | 2021-03-22 | Small-clear-distance parallel tunnel shield tunneling construction method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112682055B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114278319B (en) * | 2021-12-27 | 2023-09-26 | 中交第三航务工程局有限公司 | Shield construction method for small-clear-distance tunnel |
| CN114776323B (en) * | 2022-04-01 | 2023-04-11 | 成都未来智隧科技有限公司 | Method for controlling double compensation of stratum and stress loss of shield tunnel |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101806217B (en) * | 2010-03-12 | 2013-05-29 | 中铁四局集团有限公司 | Tunneling method for three-line parallel small-distance shallow-buried and unsymmetrical-pressure tunnel groups |
| KR101665516B1 (en) * | 2016-03-16 | 2016-10-24 | 우경기술주식회사 | Construction method of duel tunnel using composite capable of bidirectional tensioning, pressure casting and tiebolting, and its duel tunnel |
| CN110080781B (en) * | 2019-05-05 | 2021-05-07 | 济南轨道交通集团有限公司 | Construction method for shield tunnel multi-section, small-clear-distance and overlapped underpass viaduct |
| CN110374631B (en) * | 2019-06-25 | 2020-09-29 | 深圳市综合交通设计研究院有限公司 | Advanced grouting construction method for backward tunnel of small clear distance tunnel in weak stratum |
| CN211038690U (en) * | 2019-07-18 | 2020-07-17 | 中交隧道工程局有限公司 | Reinforced structure of small clear distance tunnel |
| CN110645005A (en) * | 2019-10-30 | 2020-01-03 | 中铁开发投资集团有限公司 | High-water-rich round gravel stratum earth pressure balance shield rapid tunneling construction method |
| CN111706337B (en) * | 2020-05-19 | 2022-07-15 | 北京城建中南土木工程集团有限公司 | Construction method for shield to penetrate high-speed rail |
| CN112145182A (en) * | 2020-08-25 | 2020-12-29 | 广州市市政工程设计研究总院有限公司 | Method for enabling ultra-small clear distance shield tunnel to penetrate existing line downwards |
-
2021
- 2021-03-22 CN CN202110303311.5A patent/CN112682055B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112682055A (en) | 2021-04-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100591866C (en) | Drifting sand layer and gravel stratum water-moving double-liquid high pressure slip-casting water-blocking construction method | |
| CN207377565U (en) | Constructing metro tunnel structure containing complicated geological and without shield launching place | |
| CN107725060B (en) | Subway tunnel construction method containing complex geology and without shield originating site | |
| Steiner | Tunnelling in squeezing rocks: case histories | |
| CN103334770B (en) | One is grown up reverse-slope tunnel ultra high water pressure rich water zone of fracture construction method | |
| Tseng et al. | A case study on ground treatment for a rock tunnel with high groundwater ingression in Taiwan | |
| CN106437726B (en) | Shallow-depth-excavation tunnel crosses ground fissure crushed zone construction method | |
| CN112682055B (en) | Small-clear-distance parallel tunnel shield tunneling construction method | |
| CN102758635A (en) | Construction method for tool changing under pressure in shield of water-rich silty soil and silty sand stratum under station tracks of railways | |
| CN107842374B (en) | The novel inert slurry of shield and combination grouting process for upper soft lower hard water rich strata | |
| CN109594990B (en) | Large-section jacking pipe construction method for complex stratum | |
| CN110130936B (en) | Construction method for sudden encountering untreated karst cave or crack in shield tunneling process | |
| CN203961994U (en) | Under balancing earth-pressure shielding machine, wear the concealed tunneling structure of having runed shield tunnel | |
| CN107725056A (en) | One kind passes through silly stratum tunnel loopful quick grouting construction method in advance | |
| Li et al. | Creating a working space for modifying and maintaining the cutterhead of a large-diameter slurry shield: A case study of Beijing railway tunnel construction | |
| CN108386202A (en) | City underground running tunnel list shield TBM constructions | |
| CN102400694A (en) | Reinforcement method for combined part of shield tunnel and mining-method tunnel | |
| CN110924967A (en) | Fine control construction method for shield proximity sensitive building in water-rich sandy gravel stratum | |
| CN108643929A (en) | A kind of compound stratum shield sediment improvement construction system and its construction method | |
| CN102337732A (en) | Seawall construction method with top pipes penetrating through block stone | |
| CN108005682A (en) | A kind of shield tunnel reinforcement means | |
| CN110645005A (en) | High-water-rich round gravel stratum earth pressure balance shield rapid tunneling construction method | |
| CN110130909B (en) | Construction method for shield to penetrate existing station in silt stratum | |
| CN104481555A (en) | Method of grouting and drilling construction by passing through weak surrounding rock | |
| CN108868796A (en) | For wearing skyscraper group construction method under the shield sharp radius curve and heavy grade under water-rich sand layer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |