CN113898355A - Three-hole grouting method for crescent shield gap - Google Patents
Three-hole grouting method for crescent shield gap Download PDFInfo
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- CN113898355A CN113898355A CN202111496198.3A CN202111496198A CN113898355A CN 113898355 A CN113898355 A CN 113898355A CN 202111496198 A CN202111496198 A CN 202111496198A CN 113898355 A CN113898355 A CN 113898355A
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/06—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
- E21D11/105—Transport or application of concrete specially adapted for the lining of tunnels or galleries ; Backfilling the space between main building element and the surrounding rock, e.g. with concrete
Abstract
The invention discloses a three-hole grouting method for a crescent shield gap, which comprises the following steps: dividing the shield clearance into a micro-settlement control initial stage and a shield passing stage; according to the characteristics of the shield gap in two stages, designing the arrangement position of shield gap grouting in the longitudinal direction of the shield and the arrangement form of the shield gap grouting on the cross section of the shield, namely adopting a crescent-shaped shield gap three-hole grouting method; calculating the grouting amount of the shield clearance in two stages according to the shield equipment parameters and the prefabricated segment structure design parameters, designing the shield clearance grouting construction process in two stages according to the grouting amount, and performing shield clearance grouting in two stages; and (4) calculating the grouting amount of the shield tail clearance, and performing synchronous grouting on the shield tail clearance. The method effectively reduces the total grouting amount of gap filling, has better grouting process filling effect, can effectively control micro deformation, and can also reduce the frequency of traditional secondary grouting and shorten the construction period of shield construction.
Description
Technical Field
The invention relates to the technical field of shield construction, in particular to a grouting process design in shield construction, and specifically relates to a three-hole grouting method for a crescent shield gap.
Background
The shield construction method has been gradually developed into the preferred construction method for urban underground tunnel construction because of its advantages of high mechanization degree, high tunneling speed, small influence on the surrounding environment, and the like. More than 70% of subway tunnel sections in urban central areas such as Beijing, Tianjin, Shanghai and the like adopt a shield method. With the localization of shield equipment and the improvement of labor cost, the shield method becomes the mainstream construction method of projects such as urban subways, pipe galleries, mountain tunnels and the like in the future.
The shield body is closely contacted with the stratum during shield excavation, and even if the most advanced shield is matched with the most accurate operation level, shield excavation can still be disturbed and stratum deformation is induced. According to a large amount of on-site monitoring data, multiple students study the influence process of shield tunneling on transverse and longitudinal ground surface settlement, discuss the percentage of settlement of each stage of shield tunneling in the total settlement, and analyze the influence range of shield tunneling on transverse ground surface settlement and the influence of various construction factors on ground surface settlement. The existing research shows that the displacement change process at the monitoring section can be roughly divided into 4 stages according to the relative position of the shield excavation surface and the monitoring section, wherein the shield passing (shield body passing) and the shield tail coming-off are the main stages of the deformation of the stratum around the shield tunnel. Based on the tunneling and excavating requirements of the shield, the excavating diameter of a cutter head of the shield is usually slightly larger than the outer diameters of a shield body and a prefabricated pipe piece, the shield body is generally in a conical structure with a big head and a small tail, and due to the structural characteristics of the shield, two gaps, namely a shield body gap and a shield tail gap, can be formed at the shield body and the shield tail in the excavating process respectively, so that the annular directions of the shields with different excavating diameters usually have 10-30 mm gaps as shown in fig. 1. Recently, further analysis on monitoring results of stratum deformation of Beijing subway No. 14 lines and new airport lines by the applicant shows that the stratum deformation of the shield body passing stage is about 50-60%, and the stratum deformation of the shield tail escaping stage is about 20-35%.
At present, researchers at home and abroad have developed more researches on the filling mechanism of synchronous grouting of the shield tail, performance indexes of grouting materials, a grouting process and the like on the filling of the shield tail gap, the control on the displacement of the stratum around the tunnel is mainly focused on synchronous grouting and secondary grouting on the non-uniform convergence movement trend of the soil body around the shield tail gap, and the stratum deformation at the shield tail emergence stage can be accurately controlled through the effective filling of the shield tail gap.
In the future, urban underground space development of China must be transited towards the deep level, underground rail transit tunnels and pipelines are complicated, tunnel intersection, parallel or overlapping and other close construction intervals are inevitably and frequently generated, and the crossing part also becomes a major risk source in the construction process. In 2012, in newly-built projects that No. 6 Beijing lines pass through a No. 2 line car public village station and a rising sun gate station, No. 10 lines pass through a No. 1 line public main tomb station in a second period, and No. 9 lines pass through a No. 1 line military museum station and the like, the deformation of the existing subway is strictly required to be controlled to be not more than 3 mm. Therefore, it is important to make shield gap filling in the shield passing stage, but the control method for the nonuniform convergence stratum displacement of the shield excavation gap is not mature at present, and the control requirement for stratum micro-deformation is difficult to meet only by making the shield tail gap filling.
Disclosure of Invention
In order to solve the above problems, the present invention provides a three-hole grouting method for a crescent shield gap, so as to solve the deficiencies of the shield gap grouting in the prior art and meet the requirements of the shield engineering on the micro-deformation control of the stratum and the structure.
The invention is realized by the following steps:
a three-hole grouting method for a crescent shield gap comprises the following steps:
step 1: dividing a shield body gap into two stages according to a shield construction process, wherein the first stage is a micro-settlement control initial stage, and the second stage is a shield body passing stage;
step 2: designing the arrangement position of shield gap grouting in the longitudinal direction of the shield according to the characteristics of the shield gap in the first stage and the second stage;
and step 3: according to the characteristics of the shield body gaps in the first stage and the second stage, a three-hole grouting arrangement form of 'crescent' shield body gaps on the cross section of the shield body is designed, and three holes are respectively arranged on the top of the shield shell and obliquely above the left side and the right side of the shield shell;
and 4, step 4: respectively calculating the volume of the shield gap in two stages according to shield equipment parameters and prefabricated segment structure design parameters to obtain the grouting amount of the shield gap in two stages, and designing the shield gap grouting construction process in two stages according to the grouting amount;
and 5: according to the two-stage shield body gap grouting construction process, performing two-stage shield body gap grouting;
step 6: and (4) calculating the grouting amount of the shield tail clearance, and performing synchronous grouting on the shield tail clearance.
Preferably, in step 1:
the cross section of the gap of the crescent-shaped shield body in the first stage is crescent-shaped, the vertex of the crescent-shaped shield body is positioned right above the top of the shield shell and gradually shrinks from the vertex to two sides of the shield shell, the longitudinal section is a right triangle, and the length of the long right-angle side is consistent with that of the shield body;
the cross section of the gap of the crescent shield body in the second stage is crescent, and the longitudinal section is parallelogram.
Preferably, in step 2:
the arrangement positions of the shield clearance grouting in the longitudinal direction of the shield body are as follows: in the first stage, grouting holes are formed in the middle shield and the shield tail for grouting, and in the second stage, grouting holes are formed in the middle shield only for grouting.
Preferably, in step 3:
the oblique upper parts of the left side and the right side of the shield shell are oblique positions of 60 degrees on the left side and the right side of the shield shell.
Preferably, in step 4:
the volume of the shield gap in the first stage is calculated as follows:
in the formula (I), the compound is shown in the specification,D-shield cutting outer diameter (m);
D 1 -shield tail diameter (m);
L 1 -shield length (m);
the volume of the shield gap in the second stage is calculated as follows:
in the formula (I), the compound is shown in the specification,D-shield cutting outer diameter (m);
D 1 -shield tail diameter (m);
L-length per loop (m) of the prefabricated segment.
Preferably, in step 5:
the two-stage shield body gap grouting construction process comprises the following steps:
selecting single-liquid slurry, wherein the main materials of the single-liquid slurry comprise bentonite, fly ash, cement, water glass and water;
underground stirring grouting slurry, wherein the stirring process comprises the following steps: weighing a certain amount of bentonite, adding water, stirring by a stirrer on a shield frame, adding a certain amount of cement, stirring and mixing, adding a certain amount of fly ash, continuously stirring and mixing, and finally adding water glass to form viscous grouting slurry with certain plasticity;
the grouting rate of the grouting in the gap of each shield body is relatively low within the range of 110-150%;
the grouting pressure of the shield clearance is 1.5 times of the balance soil pressure, and the grouting pressure of the shield clearance is larger than the synchronous grouting pressure of the shield tail clearance.
Preferably, in the two-stage shield gap grouting construction, a watertight layer is formed between the shield shell and the soil body, after the multiple rings are pushed, the watertight layer is formed between the prefabricated pipe piece and the soil body, and the shield tail gap is formed into a uniform gap.
Preferably, in step 6:
in the formula (I), the compound is shown in the specification,
-optimizing the grouting rate after considering the properties of the shield grouting slurry;
Preferably, the shield tail clearance caused by shield construction is optimized by considering shield body grouting
Calculated according to the following formula:
in the formula (I), the compound is shown in the specification,D 1 -Shield tail diameter (m)；
d-pre-fabricated segment outer diameter (m);
L-length per loop (m) of the prefabricated segment.
Preferably, in step 6:
and when synchronous grouting is carried out on the gap of the shield tail, synchronous grouting is carried out by adopting four holes which are respectively arranged at the upper, lower, left and right vertexes of the shield shell.
Compared with the prior art, the invention has the beneficial effects that: the three-hole grouting method for the crescent shield gap provided by the invention has the following remarkable beneficial effects:
(1) the shield body clearance is reasonably and accurately divided and accurately filled, the aim of accurately controlling sedimentation is achieved, and micro-sedimentation can be accurately and effectively controlled particularly for the shield construction to closely penetrate the overlying structures such as the existing subway, buildings and the like, which is vital to complex environment and key engineering;
(2) the shield gap grouting is accurately divided and filled, the size of the shield gap grouting is correspondingly reduced, and the total grouting amount of gap filling can be effectively reduced; the gap of the shield body is filled to form a watertight layer, so that the subsequent synchronous grouting amount can be effectively reduced, and the method is particularly suitable for sandy gravel stratum with high water permeability or stratum with underground water;
(3) the volume of the shield gap grouting is reduced, the grouting amount is small, the grouting process is simpler, the grouting slurry can be mixed in the underground site, and the slurry can be used as it is without transportation;
(4) the grouting arrangement mode and the grouting process effectively prevent grout from losing, reduce grouting rate and reduce total grouting amount of gap filling;
(5) because the gap of the shield body is filled in advance, the grouting pressure of the synchronous grouting of the shield tail can be correspondingly reduced, and the synchronous grouting of the shield tail is easier to control;
(6) the grouting method disclosed by the invention is more suitable for the actual situation of shield construction, has a better filling effect, can effectively perform micro-deformation control, and can also reduce the frequency of traditional secondary grouting and shorten the construction period of shield construction.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.
The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so that those skilled in the art can understand and read the present invention, and do not limit the conditions for implementing the present invention, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the functions and purposes of the present invention, shall fall within the scope covered by the technical contents disclosed in the present invention.
FIG. 1 is a schematic diagram of a shield body gap of a shield shell-soil body and a shield tail gap of a prefabricated segment-soil body;
FIG. 2 is a schematic diagram illustrating the effect of conventional four-hole grouting;
FIG. 3 is a schematic diagram of a shield gap in three-dimensional space according to the present invention;
FIG. 4 is a schematic view of a three-hole grouting arrangement of the present invention;
FIG. 5 is a schematic diagram of two-stage shield gap division according to the present invention;
FIG. 6 is a schematic longitudinal section of the gap grouting effect of the shield body according to the present invention;
FIG. 7 is a schematic cross-sectional view of the gap grouting effect of the shield body according to the present invention;
fig. 8 is a schematic diagram of the overall grouting filling effect of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the present invention is described in further detail below with reference to the embodiments and the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.
In the description of the present invention, the terms "comprises/comprising," "consisting of … …," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product, apparatus, process, or method if desired. Without further limitation, an element defined by the phrases "comprising/including … …," "consisting of … …," or "comprising" does not exclude the presence of other like elements in a product, device, process, or method that comprises the element.
It is to be understood that, unless otherwise expressly specified or limited, the terms "disposed," "mounted," "connected," "secured," and the like are intended to be inclusive and mean, for example, that any suitable arrangement may be utilized and that any suitable connection, whether permanent or removable, or integral, may be utilized; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
It will be further understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," "center," and the like are used in an orientation or positional relationship illustrated in the drawings for convenience in describing and simplifying the invention, and do not indicate or imply that the device, component, or structure being referred to must have a particular orientation, be constructed in a particular orientation, or be operated in a particular manner, and should not be construed as limiting the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
The following describes the implementation of the present invention in detail with reference to preferred embodiments.
At present, the control of stratum displacement around a tunnel mainly focuses on synchronous grouting and secondary grout supplement of the non-uniform convergence movement trend of soil around a shield tail gap, the synchronous grouting and the secondary grouting of the shield tail gap usually adopt a four-hole or six-hole grouting process, as shown in fig. 2, the four-hole or six-hole grouting can be diffused in a hemispherical shape at the periphery of a grouting hole, according to the grout diffusion mode, the gap at the top cannot be effectively filled, and particularly, for the flowing plastic grout, the flowing plastic grout cannot be freely diffused towards the upper part. Moreover, the lower part of the shield tunnel does not need grouting when grouting is carried out at the shield excavation clearance stage.
In addition, the traditional shield tail gap synchronous grouting is a uniformly filled circular gap, the grouting amount is the gap volume calculated by calculating the gap between the excavation surface and the prefabricated pipe piece, the loss of slurry is considered, the grouting rate is high and generally ranges from 130% to 180%, namely the grouting amount is generally 130% to 180% of the gap volume, but the shield gap is a conical gap along the length direction of the shield body and is not a regular circular gap, so the calculation of the gap volume and the grouting amount is not suitable for the shield body gap.
Therefore, in view of the obvious difference between the shield body clearance and the shield tail clearance, the shield tail clearance is usually considered as a uniform clearance in engineering, but the shield tail clearance is not uniform in reality, if the shield body clearance is still grouted by a four-hole or six-hole grouting process of shield tail clearance synchronous grouting and secondary grouting, the engineering problem to be solved cannot be solved, especially the micro-deformation control requirement of the shield body clearance, the normal propulsion of the shield is inevitably influenced, and even the potential safety hazard of the existing upper structure is caused.
Theoretically, holes can be arranged at any position of a circular ring, but the purpose of arranging the holes is pointed, and the problem can be solved practically.
On the basis of the above research, the present invention provides a three-hole grouting method for crescent shield gap, which can be specifically explained in detail by the following steps, so that the implementation can be clearly and clearly performed by those skilled in the art.
Dividing a shield body gap into two stages according to a shield construction process, wherein the first stage is a micro-settlement control initial stage, and the second stage is a shield body passing stage;
specifically, as shown in fig. 3 and 5, the cross section of the gap of the shield body in the first stage is crescent, the vertex of the crescent is located right above the top of the shield shell and is gradually reduced from the vertex to the two sides of the shield shell, the longitudinal section is a right triangle, and the length of the long right-angle side is consistent with the length of the shield body;
the cross section of the shield gap in the second stage is crescent, and the longitudinal section is parallelogram.
Secondly, designing the arrangement position of shield gap grouting in the longitudinal direction of the shield according to the characteristics of the shield gap in the first stage and the second stage;
because the gap of the shield body in the first stage is triangular in longitudinal section, and the long right-angle edge of the triangle is along the length direction of the shield body, it is determined that more grouting amount is needed to fill the gap at the position close to the tail of the shield, so that if grouting is performed only at the position of the middle shield, the whole triangular area, especially the tail of the triangle, cannot be fully injected, and meanwhile, if too much grouting liquid is injected only at the middle shield part, part of grouting liquid is likely to flow into a cutter head or the front of the cutter head, the propelling of the shield is seriously influenced, so that grouting holes are formed at the middle shield and the tail of the shield in the first stage for grouting; the cross section of the gap of the shield body in the second stage is crescent, the longitudinal section is parallelogram, and as can be seen from fig. 5 and 6, the gap is actually a small narrow strip and is positioned at the position of the middle shield, so that the better filling effect can be formed only by arranging a grouting hole on the middle shield for grouting in the second stage.
Thirdly, according to the characteristics of the shield gap in the first stage and the second stage, designing a three-hole grouting arrangement form of the shield gap grouting in the crescent-shaped shield gap on the cross section of the shield, wherein three holes are respectively arranged on the top of the shield shell and obliquely above the left side and the right side of the shield shell;
specifically, the oblique upper parts of the left side and the right side of the shield shell are oblique positions of 60 degrees on the left side and the right side of the shield shell, namely 60 degrees are inclined upwards relative to the horizontal plane of the central connecting line of the shield shell, and the optimal slurry spreading and filling effect can be formed in the soil body.
Fourthly, respectively calculating the volume of the shield gap in the two stages according to the shield equipment parameters and the prefabricated segment structure design parameters to obtain the grouting amount of the shield gap in the two stages, and designing the shield gap grouting construction process in the two stages according to the grouting amount;
the invention takes a 9.0 m-grade earth pressure balance shield suitable for a Beijing subway tunnel as an example, the diameter of a shield cutter head is 9040mm, and the length of a main engine is 12.05 m. The main technical parameters are shown in table 1, and the structural design parameters of the shield tunnel prefabricated segment are detailed in table 2.
TABLE 1 Shield tunneling equipment parameter table
Table 2 prefabricated duct piece structure design parameter table
Specifically, the first stage is a micro-settlement control initial stage, in which the hole of the excavated gap is completely filled, and therefore, the micro-settlement control initial stage is a shield gap grouting area shown in fig. 5, and the volume of the shield gap is calculated as follows:
in the formula (I), the compound is shown in the specification,D-shield cutting outer diameter (m);
D 1 -shield tail diameter (m);
L 1 -shield length (m);
calculating to obtain the shield grouting volume Q at the initial stage of micro-settlement control, namely the first stage according to the shield equipment parameters and the prefabricated segment structure design parameters1Is 6.83m3。
The second stage is an excavation gap of the shield body passing stage, because a part of the gap between the shield body and the soil body is filled by grouting, the gap is not circular along with the propulsion of the shield, and the volume of the gap of the shield body in the second stage is calculated as follows:
in the formula (I), the compound is shown in the specification,D-shield cutting outer diameter (m);
D 1 -shield tail diameter (m);
L-the length per loop (m) of the prefabricated segment;
calculating to obtain the clearance volume of 0.906m according to the shield equipment parameters and the prefabricated segment structure design parameters3。
Fifthly, performing two-stage shield clearance grouting according to the two-stage shield clearance grouting construction process;
the traditional method for obtaining a good grouting effect usually adopts double-liquid slurry, the double-liquid slurry is complex in process, the existing material suitable for grouting the shield body adopts double-liquid slurry of liquid A and liquid B, and the volume ratio difference of the liquid A and the liquid B is large, so that the requirement on a grouting pump is extremely high, and the implementation difficulty in underground grouting is large.
The invention is different from the traditional double-liquid slurry in that the shield grouting material adopts a single-liquid slurry form, and the main materials of the shield grouting material comprise bentonite, fly ash, cement, water glass and water; the invention does not need to adopt a double-slurry process, and the single slurry can meet the filling requirement, thereby avoiding the process problem of adopting double-slurry.
Is as in the conventionalThe ground mixing stations produce cement grout in different modes, and the grouting amount of gap grouting of the shield body is small, so that the shield body can be mixed underground. The gap volume of each shield body grouting is 0.906m3And the grouting material has better viscosity, so the grouting rate of the gap of the shield body can be relatively lower within the range of 110-150 percent, even if the grouting rate is 150 percent, the grouting amount of each ring is only 1.36m3Long-distance transportation is not needed, and the serous fluid quality is more easily controlled;
the underground mixing process comprises the following steps: weighing a certain amount of bentonite, adding water, stirring by a stirrer on a shield frame, adding a certain amount of cement, stirring and mixing, adding a certain amount of fly ash, continuously stirring and mixing, and finally adding water glass to form viscous grouting slurry with certain plasticity;
the slurry is viscous shield grouting slurry with certain plasticity, so that the grouting pressure of the slurry is larger than that of synchronous grouting slurry, the grouting pressure is 1.5 times of the balanced soil pressure, and meanwhile, a sensor is arranged on a grouting pipe, and the specific grouting amount and the grouting point are optimized according to the slurry consistency.
And sixthly, calculating the shield tail clearance grouting amount after the shield clearance grouting is finished through the optimization of the shield clearance grouting, and performing shield tail clearance synchronous grouting.
And when synchronous grouting is carried out on the gap of the shield tail, conventional four-hole synchronous grouting is adopted, and the four holes are respectively arranged at the upper, lower, left and right vertexes of the shield shell.
The grouting amount of the shield tail clearance is calculated according to the following formula:
in the formula (I), the compound is shown in the specification,
-the optimized grouting rate (110-150% can be taken) after considering the grouting slurry property of the shield body;
Shield tail clearance caused by considering shield body grouting optimization rear shield construction
Calculated according to the following formula:
in the formula (I), the compound is shown in the specification,D 1 -shield tail diameter (m);
d-pre-fabricated segment outer diameter (m);
L-length per loop (m) of the prefabricated segment.
Calculating to obtain the shield tail clearance of 4.47m per ring according to the shield equipment parameters and the prefabricated segment structure design parameters3According to 130% grouting rate, the grouting quantity Q of the gap between the tail of each ring shield is 5.815m3。
The traditional shield tail clearance grouting amount is calculated as follows:
in the formula (I), the compound is shown in the specification,
grouting rate (generally 130% -180%);
Vshield tail clearance (m) caused by shield construction3) Calculated according to the following formula:
in the formula (I), the compound is shown in the specification,D-shield cutting outer diameter (m);
d-pre-fabricated segment outer diameter (m);
l is the length of the backfill grouting segment, namely the length (m) of each ring of the prefabricated segment;
calculated, the gap between the shield tails of each ring is 5.38m3According to the grouting rate of 150%, the grouting quantity Q of the gap between the tail of each ring shield is 8.07m3。
Therefore, the shield tail grouting amount of the invention is reduced correspondingly even if the shield body grouting amount is added. The longitudinal section of the grouting effect of each stage is shown in FIG. 6, the shield gap filling area in FIG. 6 is the sum effect of the shield grouting in two stages after the shield advances multiple rings, and the shield tail gap grouting area is shown in FIG. 6, namely 2u in FIG. 70And (4) a region. The conventional shield tail gap grouting area is equivalent to the sum of the shield body gap filling area + the shield tail gap synchronous grouting in fig. 6, i.e. 2u in fig. 41The area, but actually more than the sum of the two parts shown in the figure, is shown by the above calculation, which shows that the grouting process of the invention can reduce the total grouting amount.
In the shield gap grouting construction process, a waterproof layer is formed between the soil body and the shield shell due to the filling of the shield gap, so that the subsequent synchronous grouting amount is effectively reduced, particularly for a sandy gravel stratum with larger water permeability or a stratum with underground water, the effect is obvious, the slurry loss is effectively prevented, the grouting rate is reduced, and the total grouting amount of gap filling can be effectively reduced. Because the gap between the shield bodies is filled, the gap between the shield tails which are originally synchronously grouted is partially filled, the volume of the synchronous grouting can be properly reduced, and the reduced grouting amount can be mainly embodied in two aspects: firstly, the volume of the shield clearance grouting is correspondingly reduced; secondly, because a part of shield grouting slurry is already arranged between the original soil body and the prefabricated pipe piece, the part of shield grouting slurry has good plasticity, and a watertight layer is also formed between the prefabricated pipe piece and the soil body, the slurry can be effectively prevented from losing in a gap of the soil body, as shown in fig. 8, and therefore, a smaller grouting rate can be selected during calculation of synchronous grouting amount, and the expected effect can be achieved.
In addition, because the original non-uniform shield tail gap is filled by shield body grouting, the shield tail gap is more uniform by filling the shield body gap, so that the grouting pressure of shield tail synchronous grouting can be correspondingly reduced, the gap needing to be filled is smaller, and the synchronous grouting is easier to control.
Meanwhile, according to the generation mechanism of the shield body clearance, the shield body clearance is divided into a micro-settlement control initial stage and a shield body passing stage, the actual situation of shield construction is better matched, grouting processes are respectively adopted in a targeted mode, the filling effect is better, micro-deformation control can be effectively carried out, the cost of soil body reinforcement is saved, the frequency of secondary grouting can be reduced, and the construction period of shield construction is shortened.
It will be readily appreciated by those skilled in the art that the above-described preferred embodiments may be freely combined, superimposed, without conflict.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A three-hole grouting method for a crescent shield gap is characterized by comprising the following steps:
step 1: dividing a shield body gap into two stages according to a shield construction process, wherein the first stage is a micro-settlement control initial stage, and the second stage is a shield body passing stage;
step 2: designing the arrangement position of shield gap grouting in the longitudinal direction of the shield according to the characteristics of the shield gap in the first stage and the second stage;
and step 3: according to the characteristics of the shield body gaps in the first stage and the second stage, a three-hole grouting arrangement form of 'crescent' shield body gaps on the cross section of the shield body is designed, and three holes are respectively arranged on the top of the shield shell and obliquely above the left side and the right side of the shield shell;
and 4, step 4: respectively calculating the volume of the shield gap in two stages according to shield equipment parameters and prefabricated segment structure design parameters to obtain the grouting amount of the shield gap in two stages, and designing the shield gap grouting construction process in two stages according to the grouting amount;
and 5: according to the two-stage shield body gap grouting construction process, performing two-stage shield body gap grouting;
step 6: and (4) calculating the grouting amount of the shield tail clearance, and performing synchronous grouting on the shield tail clearance.
2. Three-hole grouting method according to claim 1, characterised in that in step 1:
the cross section of the gap of the crescent-shaped shield body in the first stage is crescent-shaped, the vertex of the crescent-shaped shield body is positioned right above the top of the shield shell and gradually shrinks from the vertex to two sides of the shield shell, the longitudinal section is a right triangle, and the length of the long right-angle side is consistent with that of the shield body;
the cross section of the gap of the crescent shield body in the second stage is crescent, and the longitudinal section is parallelogram.
3. Three-hole grouting method according to claim 1, characterised in that in step 2:
the arrangement positions of the shield clearance grouting in the longitudinal direction of the shield body are as follows: in the first stage, grouting holes are formed in the middle shield and the shield tail for grouting, and in the second stage, grouting holes are formed in the middle shield only for grouting.
4. Three-hole grouting method according to claim 1, characterised in that in step 3:
the oblique upper parts of the left side and the right side of the shield shell are oblique positions of 60 degrees on the left side and the right side of the shield shell.
5. Three-hole grouting method according to claim 1, characterised in that in step 4:
the volume of the shield gap in the first stage is calculated as follows:
in the formula (I), the compound is shown in the specification,D-shield cutting outer diameter (m);
D 1 -shield tail diameter (m);
L 1 -shield length (m);
the volume of the shield gap in the second stage is calculated as follows:
in the formula (I), the compound is shown in the specification,D-shield cutting outer diameter (m);
D 1 -shield tail diameter (m);
L-length per loop (m) of the prefabricated segment.
6. Three-hole grouting method according to claim 5, characterised in that in step 5:
the two-stage shield body gap grouting construction process comprises the following steps:
selecting single-liquid slurry, wherein the main materials of the single-liquid slurry comprise bentonite, fly ash, cement, water glass and water;
underground stirring grouting slurry, wherein the stirring process comprises the following steps: weighing a certain amount of bentonite, adding water, stirring by a stirrer on a shield frame, adding a certain amount of cement, stirring and mixing, adding a certain amount of fly ash, continuously stirring and mixing, and finally adding water glass to form viscous grouting slurry with certain plasticity;
the grouting rate of the grouting in the gap of each shield body is relatively low within the range of 110-150%;
the grouting pressure of the shield clearance is 1.5 times of the balance soil pressure, and the grouting pressure of the shield clearance is larger than the synchronous grouting pressure of the shield tail clearance.
7. Three-hole grouting method according to claim 1, characterised in that:
in the two-stage shield body gap grouting construction, a watertight layer is formed between the shield shell and the soil body, after the multiple rings are pushed, the watertight layer is formed between the prefabricated pipe pieces and the soil body, and the shield tail gap is formed into a uniform gap.
8. Three-hole grouting method according to claim 7, characterised in that in step 6:
the shield tail clearance grouting amount is calculated as follows:
in the formula (I), the compound is shown in the specification,
-optimizing the grouting rate after considering the properties of the shield grouting slurry;
9. Three-hole grouting method according to claim 8, characterised in that:
shield tail clearance caused by considering shield body grouting optimization rear shield construction
Calculated according to the following formula:
in the formula (I), the compound is shown in the specification,D 1 -shield tail diameter (m);
d-pre-fabricated segment outer diameter (m);
L-length per loop (m) of the prefabricated segment.
10. Three-hole grouting method according to claim 1, characterised in that in step 6:
and when synchronous grouting is carried out on the gap of the shield tail, synchronous grouting is carried out by adopting four holes which are respectively arranged at the upper, lower, left and right vertexes of the shield shell.
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| CN202111496198.3A CN113898355A (en) | 2021-12-09 | 2021-12-09 | Three-hole grouting method for crescent shield gap |
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