CN108643922B - Large-diameter slurry shield comprehensive tunneling method for highly permeable soil-rock composite stratum - Google Patents
Large-diameter slurry shield comprehensive tunneling method for highly permeable soil-rock composite stratum Download PDFInfo
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- CN108643922B CN108643922B CN201810348840.5A CN201810348840A CN108643922B CN 108643922 B CN108643922 B CN 108643922B CN 201810348840 A CN201810348840 A CN 201810348840A CN 108643922 B CN108643922 B CN 108643922B
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- 230000005641 tunneling Effects 0.000 title claims abstract description 112
- 238000000034 method Methods 0.000 title claims abstract description 66
- 239000002002 slurry Substances 0.000 title claims abstract description 62
- 239000011435 rock Substances 0.000 title claims abstract description 60
- 239000002131 composite material Substances 0.000 title claims abstract description 49
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 39
- 238000010276 construction Methods 0.000 claims abstract description 31
- 238000005520 cutting process Methods 0.000 claims abstract description 22
- 239000007788 liquid Substances 0.000 claims abstract description 12
- 230000001360 synchronised effect Effects 0.000 claims abstract description 12
- 238000004886 process control Methods 0.000 claims abstract description 5
- 230000008569 process Effects 0.000 claims description 25
- 239000000463 material Substances 0.000 claims description 21
- 238000009412 basement excavation Methods 0.000 claims description 19
- 238000009991 scouring Methods 0.000 claims description 17
- 230000002265 prevention Effects 0.000 claims description 16
- 238000005422 blasting Methods 0.000 claims description 13
- 238000013461 design Methods 0.000 claims description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 11
- 230000008859 change Effects 0.000 claims description 10
- 238000012937 correction Methods 0.000 claims description 9
- 239000000741 silica gel Substances 0.000 claims description 8
- 229910002027 silica gel Inorganic materials 0.000 claims description 8
- 239000000440 bentonite Substances 0.000 claims description 6
- 229910000278 bentonite Inorganic materials 0.000 claims description 6
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims description 6
- 239000003795 chemical substances by application Substances 0.000 claims description 6
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- 238000002347 injection Methods 0.000 claims description 5
- 239000007924 injection Substances 0.000 claims description 5
- 239000004568 cement Substances 0.000 claims description 4
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- 230000035699 permeability Effects 0.000 claims description 4
- 238000002360 preparation method Methods 0.000 claims description 4
- 230000002159 abnormal effect Effects 0.000 claims description 3
- 239000003638 chemical reducing agent Substances 0.000 claims description 3
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- 238000007667 floating Methods 0.000 claims description 3
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- 235000019353 potassium silicate Nutrition 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 239000004576 sand Substances 0.000 claims description 3
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 3
- 230000001502 supplementing effect Effects 0.000 claims description 3
- 239000002699 waste material Substances 0.000 claims description 3
- 238000011010 flushing procedure Methods 0.000 claims description 2
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/006—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries by making use of blasting methods
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/001—Improving soil or rock, e.g. by freezing; Injections
- E21D9/002—Injection methods characterised by the chemical composition used
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/06—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
- E21D9/08—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining with additional boring or cutting means other than the conventional cutting edge of the shield
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/06—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
- E21D9/093—Control of the driving shield, e.g. of the hydraulic advancing cylinders
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- Geology (AREA)
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Abstract
The invention provides a large-diameter slurry shield comprehensive tunneling method for a strong permeable soil-rock composite stratum, which relates to the field of shield construction, wherein a composite normal-pressure cutter head is adopted as a cutter head, a cutter position is arranged on the cutter head, a cutter capable of being replaced at normal pressure is arranged on the cutter position, the cutter position comprises a type I cutter position fixed in a cutter mode and a type II cutter position capable of realizing normal-pressure hobbing interchange, a fixed cutter is arranged on the type I cutter position, an interchangeable cutter is arranged on the type II cutter position, and the cutting track of the interchangeable cutter covers the cutter head; the tunneling process control comprises cutter head rotating speed control, cutter head thrust and torque control, incision pressure control, attitude control and synchronous grouting construction parameter control; the synchronous grouting construction adopts hard single-liquid slurry with water-resistant dispersion. By adopting the composite normal-pressure cutter head, two types of cutters are respectively arranged on the composite normal-pressure cutter head, the cutting tracks of the whole cutter head are covered by the two types of cutter positions, the cutters are fixed to cut soil, and the cutters can be exchanged to cut rock mass, so that the smooth tunneling of composite geology is ensured.
Description
Technical Field
The invention provides a large-diameter slurry shield comprehensive tunneling method for a strong permeable soil-rock composite stratum, and relates to the field of shield construction.
Background
The slurry shield construction method is a very mature tunnel construction method, and due to the advantages of small environmental disturbance, high construction efficiency and good stratum adaptability, the method is selected in subway construction in more and more cities along with the rise of subway construction industry in China. However, due to the regionality and uniqueness of geotechnical engineering, the slurry shield cannot avoid meeting some special engineering geological conditions in the process of building urban subway tunnels, and at present, the most difficult problem is to go up and down the soil-rock composite stratum.
Due to the fact that the difference of physical and mechanical properties of soil bodies and rock bodies is large, when the two materials exist in the excavation face of the slurry shield at the same time, the working conditions and the state changes of all systems of the shield are severe, and the technical problems that a cutter head tool is seriously abraded, a cutter head is easy to form mud cakes, the tunneling speed is slow, the tunneling direction deviates and the like are directly caused, and if the permeability coefficient of the upper soil body is high, the problems that the excavation face with poor mud film quality is unstable, the pressure is difficult to enter a bin under pressure and the pressure is maintained can also.
The existing composite geological construction method mostly adopts an earth pressure balance shield, and the related control technology of slurry shield tunneling construction in a strong permeable soil-above and soil-below rock composite stratum is not perfect.
Meanwhile, in the prior art, the stability maintenance or the ground surface settlement control of the structure built near the shield crossing region is not considered, the construction method is suitable for homogeneous strata (compared with composite strata) without considering the special geological conditions of the shield crossing, most patent research objects are earth pressure balance shields, and the invention has little significance for the patent inspiration.
Disclosure of Invention
In order to solve the problems, the invention provides a large-diameter slurry shield comprehensive tunneling method for a strong permeable soil-rock composite stratum, which can improve the tunneling construction efficiency of the large-diameter slurry shield through the strong permeable soil-rock composite stratum.
The technical scheme of the invention is as follows: a large-diameter slurry shield comprehensive tunneling method for a strong permeable soil-rock composite stratum comprises a shield tunneling method and a shield mud cake prevention treatment method; the shield tunneling method comprises two parts of shield preparation before tunneling and tunneling process control; the shield preparation before tunneling comprises cutter head model selection and cutter configuration, wherein a composite normal-pressure cutter head is adopted as the cutter head, a cutter position is arranged on the cutter head, a cutter capable of being replaced at normal pressure is installed on the cutter position, the cutter position comprises a type I cutter position fixed in a cutter form and a type II cutter position capable of realizing normal-pressure hobbing interchange, a fixed cutter is installed on the type I cutter position, an interchangeable cutter is installed on the type II cutter position, and the cutting track of the interchangeable cutter covers the cutter head; the tunneling process control comprises cutter head rotating speed control, cutter head thrust and torque control, incision pressure control, attitude control and synchronous grouting construction parameter control; the synchronous grouting construction adopts hard single-liquid slurry with water-resistant dispersibility.
The hard single-liquid slurry is prepared from materials mainly comprising cement, bentonite, fly ash, sand, a plastic retaining agent, a water reducing agent and water, wherein the initial setting time of the hard single-liquid slurry is 6-10 hours, the consistency is 8-12 cm, the expansion degree is 52-58 cm, and the strength of the proportioning material of the hard single-liquid slurry is matched with that of the surrounding stratum.
For spherical weathered rock bodies (namely boulders) with higher strength, blasting pretreatment is required before shield tunneling because the shield cannot effectively cut: firstly blasting the high-strength rock mass in the tunneling section, and then grouting and consolidating to ensure that the reinforced broken rock mass can maintain self stability so as to perform shield tunneling cutting.
The blasting construction in the process is basically the same as the conventional blasting construction process, and the difference is that the positions of explosive discharge and detonation of drilling holes are on the ground or on the water surface, three rows of blast holes with two short holes and one long hole are distributed along the shield tunneling direction in each blasting, the distance between the blast holes is 0.6-0.8 m, and the hole positions are basically overlapped with the shield tunneling boundary.
And (3) combining geological survey data, if a broken zone rock mass exists in a geological section, performing grouting pre-consolidation treatment on the broken rock mass in front of the shield tunneling, and ensuring that the shield can effectively cut when passing through the broken rock mass.
The technical scheme of the invention also comprises: the cutter configuration adopts a cutter system formed by matching a shell-type advanced cutter and a scraper, the interior of the cutter head is of a hollow structure, the I-type cutter position is arranged in the middle of the cutter head, the II-type cutter position is arranged on the outer ring of the cutter head, and the cutter height of the interchangeable cutter is greater than that of the fixed cutter.
The two types of cutter positions cover the cutting track of the whole cutter head, the cutter abrasion amount is large when cutting is carried out on an earth-rock composite stratum or a rock stratum, long-distance tunneling of a shield is realized by adopting a normal-pressure cutter changing technology according to the monitored abrasion condition of a cutter abrasion monitoring device in construction, and the cutter changing time can be greatly shortened by adopting the normal-pressure cutter changing technology.
In order to solve the problem that a cutter head is easy to form mud cakes, the shield mud cake prevention and treatment method comprises a shield mud cake prevention method and a shield mud cake treatment method; the shield mud cake prevention method comprises the steps that a center scouring knife and a knife cylinder are installed in the center of a cutter head, a scouring nozzle is arranged on the center scouring knife and is communicated with a mud channel, and the knife cylinder is communicated with P0.1Pump connection, mud pressure from P0.1Controlling the pump; the shield mud cake prevention method and the shield tunneling are synchronously implemented.
In the normal tunneling process of the shield, the change conditions of tunneling parameters and cutter head temperature are monitored in real time, when the tunneling parameters are abnormal, a mud cake dispersing agent is firstly added into mud, and the change conditions of relevant parameters are further analyzed: if the parameters are stable, the tunneling can be continued and the normal tunneling can be recovered under the appropriate condition; if the temperature monitored by the cutter head temperature monitoring system continuously rises and the tunneling parameters continuously change, after determining that mud cakes are generated at the center body of the cutter head, the shield stops to clean the mud cakes.
The shield mud cake treatment method comprises the following steps: the shield stops tunneling, under the condition that the pressure of the mud water on the excavation surface is kept constant, a center scouring cutter is selected to be replaced by a self-rotating cutting water cutter, the self-rotating cutting water cutter is communicated with a high-pressure pump set, the high-pressure pump set provides high-pressure water for the self-rotating cutting water cutter to cut and clean mud cakes at the center scouring cutter, the mud cakes near other cutters are sequentially cleaned after cleaning is finished, and shield tunneling is recovered until the center mud cakes are cleaned.
Meanwhile, the excavation diameter of the shield tunneling machine is slightly larger than that of the shield body, the diameter of the shield body is slightly larger than that of the shield tail, the excavation diameter of the shield tunneling machine reaches 12.55 meters, the diameter of the front shield body is 12.51 meters, the diameter of the middle shield body is 12.49 meters, and the diameter of the shield tail is 12.47 meters, so that a gap between an excavation surface and the shield tail is about 4cm, the space is a taper space before segment grouting is carried out after a segment is separated from the shield tail, the tunneling space is set for reducing the extrusion force and the friction force of a soil body on the shield tunneling machine, and a space with top settlement is possibly formed in the tunneling process.
In order to reduce the settlement caused by the conicity formed by the excavation surface and the shield body, an inert material is synchronously injected outside the shield body through the upper radial hole reserved in the shield body in the shield advancing process, and the gap between the excavation diameter and the shield body is filled in time. The injection rate is 120-130%. In the shield advancing process, an inert filling material is injected into a gap between a shield body and a shield tail from the outer side of a shield shell to the cutter head overexcavation part in the radial direction at an injection rate of 120-130%, and meanwhile, ground surface settlement is monitored, and construction parameters of the inert filling material are controlled.
The inert material is prepared by mixing the ground stability control agent powder and the water glass in a ratio of 20:1, then injecting the mixture into a taper space with the excavation diameter and the shield diameter, has certain strength and supporting force, does not condense for a long time, and can control the settlement caused by the fact that the taper space cannot be filled in time.
The technical scheme of the invention also comprises: before the compound stratum that permeates water by a great deal of height carries out the operation of opening the storehouse, use mud mould shaping promoter to assist mud and form the mud membrane of high elastic modulus, hyposmosis to it is stable to ensure the atmospheric pressure of the in-process of opening the storehouse, mud mould shaping promoter includes pressurize silica gel and silica gel coagulant, the silica gel coagulant injects into the mud that blade disc the place ahead was mixed with pressurize silica gel through the high pressure water jet who constructs from the area, rotates the misce bene through the blade disc in the mud that the blade disc was mixed.
In the shield tunneling process, the control on the rotation speed of the cutter head, the thrust and torque of the cutter head, the notch pressure, the attitude and the synchronous grouting construction parameters needs to be enhanced.
The rotating speed of the cutter head needs to be determined by comprehensively considering the torque of the cutter head and the abrasion loss of a cutter, and the rotating speed of the cutter head is 0.8-1.3 r/min in the process of tunneling the composite stratum.
The thrust and the torque of a cutter head in the composite stratum are two relevant parameters, generally, when the composite stratum is tunneled, the thrust of the cutter head is controlled to be 40% -65% of the design value of the thrust, the torque is controlled to be 30% -65% of the design torque, and the maximum value of the thrust and the torque of the cutter head is not more than 70% of the design value.
The pressure fluctuation of the cut of the tunnel face is strictly controlled in the tunneling process, the actual operation cut pressure is slightly larger than the theoretical calculation value by 0-0.2 bar, and the difference is not too large so as to prevent the top of the tunnel face from being punctured.
The main material of the slurry is bentonite, and the specific gravity of the slurry is controlled to be 1.1-1.2 g/cm under the normal tunneling state3The viscosity is controlled to be more than 23S, and the property of the product has better stability. And (4) detecting the slurry index at regular time, discharging the waste slurry and supplementing new slurry in time.
And in the upper soft and lower hard stratum, the management of selecting the point positions of the pipe pieces is enhanced. When the floating amount of the duct piece is large, the shield attitude is dynamically adjusted and the duct piece splicing point position is selected according to the principle that the duct piece attitude is adaptive to the shield attitude. When the deviation of the upper soft and lower hard stratum is corrected, a partition oil pressure difference mode is adopted, and the technical means of changing the using number of oil cylinders and stress release can be adopted under special conditions. The deviation correction should follow the principle of long-distance slow correction, and the deviation correction radius must be larger than the deviation radius.
The invention has the beneficial effects that: the invention provides a comprehensive tunneling method for a large-diameter slurry shield of a strong permeable soil-rock composite stratum, which is characterized in that a composite normal-pressure cutter head is adopted, a fixed cutter fixed in a cutter form and an interchangeable cutter capable of realizing normal-pressure hobbing interchange are respectively arranged on the composite normal-pressure cutter head, two types of cutter positions cover the cutting track of the whole cutter head, the cutter is fixed to cut soil, and the interchangeable cutter is used to cut rock, so that the smooth tunneling of composite geology is ensured.
The cutter abrasion loss is large when the earth-rock composite stratum or the rock stratum is cut, the cutter changing time can be greatly shortened by adopting the normal-pressure cutter changing technology, and meanwhile, the long-distance tunneling of the shield can be realized, so that the construction progress is effectively guaranteed.
In the shield tunneling process, the control on the rotation speed of the cutter head, the thrust and torque of the cutter head, the notch pressure, the attitude and the synchronous grouting construction parameters needs to be enhanced. The synchronous grouting slurry adopts hard single-liquid slurry with water-resistant dispersion for resisting the strong water permeability of high-water-level stratum, so that the normal construction environment is guaranteed.
Drawings
FIG. 1 is a schematic view of a cutter head structure according to the present invention;
FIG. 2 is a schematic illustration of the fill material injection of the present invention;
FIG. 3 is a schematic view of the installation of the center flush cutter of the present invention;
FIG. 4 is an enlarged view of a portion of FIG. 3;
fig. 5 is a schematic diagram of arrangement of the boulder blasting blastholes of the invention.
Wherein, 1, cutterhead, 2, interchangeable cutter.
Detailed Description
The invention will be further described with reference to the accompanying drawings and examples.
Meanwhile, since only some embodiments are described below, the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
Example one
For the compound stratum of the upper soil and the lower rock, before the shield is formally tunneled, the type selection of a cutter head 1 and the configuration of cutters are needed.
As shown in fig. 1, the knife disc 1 innovatively adopts the design form of the combined type normal pressure knife disc 1, the inner design is a hollow structure, and two types of knife positions are arranged on the surface of the knife disc 1: the middle part of the cutter head 1 is a type I cutter position fixed in a cutter form, the outer ring of the cutter head 1 is a type II cutter position (shown as a circled position in figure 1) capable of realizing normal pressure hobbing interchange, the proportion of the two types of cutter positions in the shield tunneling process is determined according to the proportion of soil and rock mass in the shield tunneling section and the invasion height of the rock mass, and the cutting track of the hobbing cutter in the composite stratum can be ensured to basically cover the rock mass.
The opening rate of the cutter head 1 is determined by comprehensively considering the percentage of the cross-section rock mass and the rock mass mechanical index, meanwhile, the working space of the normal pressure cutter changing technology is ensured, generally 25% -35%, and larger torque can be brought by the excessively large opening rate of the cutter head 1.
The cutter adopts a cutter system formed by matching a shell-type advance cutter and a scraper, the cutting track of the normal-pressure replaceable cutter covers the whole cutter head 1, the cutters are arranged in a layering manner, the height of the interchangeable cutter 2 is greater than that of the fixed cutter, a certain number of normal-pressure replaceable hobs are arranged on the outer ring of the cutter head 1, and the cutting edge of the normal-pressure replaceable hob is highest.
When the shield is tunneled in a composite stratum, the arrangement form of the hobbing cutters on the II-type cutter positions is adjusted according to the proportion of rock bodies in the tunneling section based on the hobbing cutter arrangement principle of 'rock breaking by a hobbing cutter and soil cutting by a gear cutter', and the hobbing cutter arrangement form is replaced by using a normal-pressure hobbing exchange technology.
The two types of cutter positions cover the cutting track of the whole cutter head 1, the cutter abrasion loss is large when the earth-rock composite stratum or the rock stratum is cut, and long-distance tunneling of the shield is realized by adopting a normal-pressure cutter changing technology according to the abrasion condition monitored by the cutter abrasion monitoring device in construction so as to shorten the cutter changing time.
The class I cutter position tool changing comprises 7 steps of loading ① telescopic oil cylinders, fixing ② pendulum-type sleeves, fixing ③ telescopic oil cylinder lifting lugs, loosening ④ bolts of the cutter cylinder to draw the cutter cylinder back, closing the gate plate while flushing ⑤, detaching ⑥ cutter cylinders and taking off the cutter heads, and checking ⑦ to change new tools or install old tools again.
The hobbing interchange operation on the type II cutter position is basically consistent with that of the hobbing interchange operation on the type II cutter position I, and the main difference is that ① tool changing auxiliary tools are different, a pendulum type sleeve is used for replacing the type I cutter position, a cutter barrel bracket and a cutter barrel clamp are used for the type II cutter position II, and a wear detector needs to be closed before the hobbing cutter on the type ② type II cutter position II is replaced.
The control of the rotation speed of the cutter head 1, the thrust and the torque of the cutter head 1, the notch pressure, the attitude and the synchronous grouting construction parameters is enhanced in the control of the tunneling process.
Mainly comprises the following aspects:
(1) the rotating speed of the cutter head 1 is determined by comprehensively considering the torque of the cutter head 1 and the abrasion loss of a cutter, and the rotating speed of the composite stratum cutter head 1 is controlled to be 0.8-1.3 r/min.
(2) The thrust and the torque of the cutter head 1 in the composite stratum are two related parameters, and in general, when tunneling in the composite stratum, the thrust of the cutter head 1 is controlled to be 40-65% of the design value of the thrust, the torque is controlled to be 30-65% of the design torque, and the maximum value of the thrust and the torque cannot exceed 70% of the design value.
(3) The pressure fluctuation of the cut of the tunnel face is strictly controlled in the tunneling process, the actual operation cut pressure is slightly larger than the theoretical calculation value by 0-0.2 bar, and the difference is not too large so as to prevent the top of the tunnel face from being punctured.
(4) The main material of the slurry is bentonite, the specific gravity of the slurry is controlled to be 1.1-1.2 g/cm3 under the normal tunneling state, the viscosity is controlled to be more than 23S, and the slurry has good stability. And (4) detecting the slurry index at regular time, discharging the waste slurry and supplementing new slurry in time.
(5) The key point of attitude control is not the absolute value of the deviation of the shield or the segment from the design axis, but the relative position relationship of the shield and the segment, and the management of segment point location selection should be strengthened in the upper, soft and lower hard strata. When the floating amount of the duct piece is large, the shield attitude is dynamically adjusted and the duct piece splicing point position is selected according to the principle that the duct piece attitude is adaptive to the shield attitude. When the deviation of the upper soft and lower hard stratum is corrected, a partition oil pressure difference mode is adopted, and the technical means of changing the using number of oil cylinders and stress release can be adopted under special conditions. The deviation correction should follow the principle of long-distance slow correction, and the deviation correction radius must be larger than the deviation radius.
(6) Synchronous grouting construction parameters
The synchronous grouting slurry adopts rigid single-liquid slurry, must have water-resistant dispersibility to resist the strong water permeability of high-water-level strata, the materials comprise cement, bentonite, fly ash, sand, a plastic retention agent, a water reducing agent and water, the initial setting time is 6-10 hours, the consistency is 8-12 cm, the expansion degree is 52-58 cm, the strength of the proportioning material is matched with the peripheral strata, the 28-day compressive strength of the soil strata is more than 1MPa, the mixing amount of the fly ash and the cement can be properly improved in the rock strata, the 28-day compressive strength is 2-3 MPa, but the initial setting time is required to be ensured to prevent pipe blockage.
The grouting pressure comprehensively considers factors such as stratum conditions, segment strength, slurry performance, slurry pressure and the like, the general grouting pressure P = P1 (slurry pressure value at a grouting point) + P2 (pressure loss of a grouting pipeline) + P3 (30-50 kPa) adopts time-sharing point-by-point uninterrupted grouting as a main part and manual grouting as auxiliary grouting control in the tunneling process.
And the grouting amount is V = (pi/4) × (D2-D2) × 2(D is the excavation diameter of the cutter head 1, D is the outer diameter of the lining pipe piece) according to the theoretical grouting amount per ring (2 meters) of the geological condition of the stratum, the filling coefficient is not less than 1.3, and the normal control is 1.3-1.8. Taking the Wuhan subway No. 8 line river crossing shield tunnel as an example, the slurry shield with the diameter of 12.55 meters is actually formed in the upper soft lower hard stratum by the grouting amount meeting the grouting pressure of 19 m3The field is controlled to be 22-23 m3。
Example two
On the basis of the first embodiment, the prevention and treatment work of the mud cake of the cutter head 1 is enhanced.
The prevention and control of the mud cake in the center body of the cutter head 1 comprises two technical measures of prevention and treatment, and various devices and materials including a developed center scouring cutter with a scouring function, a mud cake cutting water cutter, a cutter head 1 temperature real-time monitoring system and a mud cake dispersing agent are comprehensively used, and the prevention and control of the mud cake are carried out together with shield tunneling parameters.
The prevention of the mud cake of the cutter head 1 is to replace the original center scouring knife of the cutter head 1 with a center scouring knife with a scouring nozzle and a mud channel, and the rear part of the knife cylinder is connected with a rear part P0.1The pressure of the slurry is adjusted according to the actual condition, and the slurry is sprayed out from the washing nozzle to wash away the muck and the existing mud cakes while the shield is tunneling and cutting soil, so that the problem that the mud cakes are formed on the cutter head 1 due to the fact that the opening rate of the central area of the cutter head 1 is too low is prevented. The prevention of the mud cake of the cutter head 1 and the shield tunneling are synchronously carried out.
In the normal tunneling process of the shield, the tunneling parameters and the temperature change condition of the cutter head 1 are monitored in real time, when the tunneling parameters are abnormal, a mud cake dispersing agent is firstly added into the slurry, and the change condition of the related parameters is further analyzed: if the parameters are stable, the tunneling can be continued and the normal tunneling can be recovered under proper conditions (namely, the mud cake dispersing agent is not added in the mud); if the temperature monitored by the temperature monitoring system of the cutter head 1 continuously rises and the tunneling parameters continuously change, after the mud cake is determined to be generated at the central body of the cutter head 1 according to the prior experience, the shield is required to be stopped for cleaning the mud cake.
When the mud cake is formed at the central body of the shield cutter head 1, the shield stops tunneling, under the condition that the pressure of the mud water at the excavation surface is kept constant, a central scouring cutter is selected to be replaced by a water cutter which is designed by self development, a high-pressure pump set is connected behind the water cutter, the mud cake at the central scouring cutter is cut and cleaned by using high-pressure water, the mud cakes near other cutters are cleaned in sequence after the cleaning is finished, and the shield propulsion is recovered until the central mud cake is cleaned.
EXAMPLE III
The excavation diameter of the shield tunneling machine is slightly larger than that of the shield body, the diameter of the shield body is slightly larger than that of the shield tail, the excavation diameter of the shield tunneling machine reaches 12.55 meters, the diameter of the front shield body is 12.51 meters, the diameter of the middle shield body is 12.49 meters, and the diameter of the shield tail is 12.47 meters, so that a gap between an excavation surface and the shield tail is about 4cm, the space is a taper space before segment grouting after the segment is separated from the shield tail, the space is arranged for reducing extrusion force and friction force of soil body to the shield tunneling machine, but a space with top settlement is possibly formed in the tunneling process.
In order to reduce the settlement caused by the conicity formed by the excavation surface and the shield body, an inert material is synchronously injected outside the shield body through the upper radial hole reserved in the shield body in the shield advancing process, and the gap between the excavation diameter and the shield body is filled in time. The injection rate is 120-130%.
The inert material is prepared by mixing the ground stability control agent powder and the water glass in a ratio of 20:1, then injecting the mixture into a taper space with the excavation diameter and the shield diameter, has certain strength and supporting force, does not condense for a long time, and can control the settlement caused by the fact that the taper space cannot be filled in time.
Example four
For spherical weathered rock bodies (namely boulders) with higher strength, blasting pretreatment is required before shield tunneling because the shield cannot effectively cut: firstly blasting the high-strength rock mass in the tunneling section, and then grouting and consolidating to ensure that the reinforced broken rock mass can maintain self stability so as to perform shield tunneling cutting.
The blasting construction in the process is basically the same as the conventional blasting construction process, and the difference is that the positions of explosive discharge and detonation of drilling holes are on the ground or on the water surface, three rows of blast holes with two short and one long are distributed along the shield tunneling direction in each blasting, the distance between the blast holes is 0.6-0.8 m, and the hole positions are basically superposed with the shield tunneling boundary. The grouting reinforcement process of the broken rock mass after blasting is the same as the conventional grouting reinforcement process, the grouting pressure is determined according to the water and soil pressure of the grouting area, the grouting range covers the broken rock mass, and the grouting holes are sealed by using double-liquid grout after the rock mass reinforcement is completed.
EXAMPLE five
And (3) combining geological survey data, if a broken zone rock mass exists in a geological section, performing grouting pre-consolidation treatment on the broken rock mass in front of the shield tunneling, and ensuring that the shield can effectively cut when passing through the broken rock mass.
The above description is only exemplary of the present invention and should not be taken as limiting the invention in any way, and any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (14)
1. A large-diameter slurry shield comprehensive tunneling method for a strong permeable soil-rock composite stratum is characterized by comprising the following steps: comprises a shield tunneling method and a shield mud cake prevention treatment method; the shield tunneling method comprises two parts of shield preparation before tunneling and tunneling process control; the shield preparation before tunneling comprises cutter head model selection and cutter configuration, wherein a composite normal-pressure cutter head is adopted as the cutter head, a cutter position is arranged on the cutter head, a cutter capable of being replaced at normal pressure is installed on the cutter position, the cutter position comprises a type I cutter position fixed in a cutter form and a type II cutter position capable of realizing normal-pressure hobbing interchange, a fixed cutter is installed on the type I cutter position, an interchangeable cutter is installed on the type II cutter position, and the cutting track of the cutter covers the cutter head; the tunneling process control comprises cutter head rotating speed control, cutter head thrust and torque control, incision pressure control, attitude control and synchronous grouting construction parameter control; the synchronous grouting construction adopts hard single-liquid slurry with water-resistant dispersibility; the hard single-liquid slurry is prepared from materials mainly comprising cement, bentonite, fly ash, sand, a plastic retention agent, a water reducing agent and water, wherein the initial setting time of the hard single-liquid slurry is 6-10 hours, the consistency is 8-12 cm, the expansion degree is 52-58 cm, and the strength of the proportioning material of the hard single-liquid slurry is matched with that of the surrounding stratum;
a gap is formed between the excavation surface and the shield tail, and the gap is a taper space before the duct piece is separated from the shield tail and duct piece wall back grouting is not carried out; in the shield advancing process, an inert filling material is injected into a gap between a shield body and a shield tail from the outer side of a shield shell to the cutter head overexcavation part in the radial direction through an upper radial hole reserved in the shield body at an injection rate of 120-130%, meanwhile, the ground surface settlement is monitored, and the construction parameters of the inert filling material are controlled, wherein the inert filling material is prepared by mixing stratum stability control agent powder and water glass in a ratio of 20: 1.
2. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 1, which is characterized in that: when the spherical weathered rock mass is blasted, the positions of explosive discharge and detonation of the drill holes are on the ground or water surface, three rows of blast holes with two short holes and one long hole are distributed along the shield tunneling direction in each blasting, the distance between the blast holes is 0.6-0.8 m, and the hole positions are basically overlapped with the shield tunneling boundary.
3. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 1, which is characterized in that: and (3) grouting and pre-solidifying the broken rock mass in front of the shield tunneling when the broken zone rock mass exists in the geological section.
4. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 1, which is characterized in that: the cutter configuration adopts a cutter system formed by matching a shell-type advanced cutter and a scraper, the interior of the cutter head is of a hollow structure, the I-type cutter position is arranged in the middle of the cutter head, the II-type cutter position is arranged on the outer ring of the cutter head, and the cutter height of the interchangeable cutter is greater than that of the fixed cutter.
5. The comprehensive tunneling method of the large-diameter slurry shield in the soil-rock composite stratum with the strong water permeability as claimed in claim 4, wherein the cutter can be replaced under normal pressure, and the step of replacing the cutter under the normal pressure mainly comprises the steps of loading ① telescopic oil cylinders, fixing ② cutter-changing auxiliary tools, fixing ③ telescopic oil cylinder lifting lugs, loosening ④ bolts of the cutter cylinders to draw back the cutter cylinders, closing the flashboards while flushing ⑤, detaching ⑥ cutter cylinders and taking off the cutter heads, and checking ⑦ to replace new cutters or install old cutters.
6. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 1, which is characterized in that:
the shield mud cake prevention treatment method comprises a shield mud cake prevention method and a shield mud cake treatment method;
the shield mud cake prevention method comprises the steps that a center scouring knife and a knife cylinder are installed in the center of a cutter head, a scouring nozzle is arranged on the center scouring knife and is communicated with a mud channel, and the knife cylinder is communicated with P0.1Pump connection, mud pressure from P0.1Controlling the pump;
the shield mud cake prevention method and the shield tunneling are synchronously implemented;
in the normal tunneling process of the shield, the change conditions of tunneling parameters and cutter head temperature are monitored in real time, when the tunneling parameters are abnormal, a mud cake dispersing agent is firstly added into mud, and the change conditions of relevant parameters are further analyzed:
if the parameters are stable, the tunneling can be continued and the normal tunneling can be recovered under the appropriate condition;
if the temperature monitored by the cutter head temperature monitoring system continuously rises and the tunneling parameters continuously change, after determining that mud cakes are generated at the center body of the cutter head, the shield stops to clean the mud cakes.
7. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 6, which is characterized in that: the shield mud cake treatment method comprises the following steps:
the shield stops tunneling, under the condition that the pressure of the mud water on the excavation surface is kept constant, a center scouring cutter is selected to be replaced by a self-rotating cutting water cutter, the self-rotating cutting water cutter is communicated with a high-pressure pump set, the high-pressure pump set provides high-pressure water for the self-rotating cutting water cutter to cut and clean mud cakes at the center scouring cutter, the mud cakes near other cutters are sequentially cleaned after cleaning is finished, and shield tunneling is recovered until the center mud cakes are cleaned.
8. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 1, which is characterized in that: before the high water level strong permeable composite stratum is subjected to the warehouse opening operation, the mud is assisted by the mud mold forming accelerant to form a high-elasticity mold and a low-permeability mud film, the mud mold forming accelerant comprises pressure maintaining silica gel and a silica gel coagulant, the silica gel coagulant is injected into the mud mixed with the pressure maintaining silica gel in front of the cutter head through the high-pressure water nozzle of the shield, and the mud is rotated and uniformly mixed through the cutter head.
9. The method for the comprehensive tunneling of the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to any one of claims 1 to 8, characterized by comprising the following steps: the rotating speed of the cutter head is controlled to be 0.8-1.3 r/min in the process of tunneling the shield in the composite stratum.
10. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 9, which is characterized in that: the cutter thrust and the torque are controlled in such a way that when tunneling in a composite stratum, the cutter thrust is controlled to be 40-65% of a design value of the thrust, the torque is controlled to be 30-65% of the design torque, and the maximum value of the cutter thrust and the torque is not more than 70% of the design value.
11. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 9, which is characterized in that: and the incision pressure control is that the incision pressure of the control tunnel face in the tunneling engineering is 0-0.2 bar greater than the theoretical calculated value.
12. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 9, which is characterized in that: the main material of the slurry is bentonite, and the specific gravity of the slurry is controlled to be 1.1-1.2 g/cm under the normal tunneling state3And controlling the viscosity to be more than 23S, detecting the slurry index at regular time, and discharging the waste slurry and supplementing new slurry in time.
13. The method for comprehensively tunneling the large-diameter slurry shield in the strongly permeable soil-rock composite stratum according to claim 1, which is characterized in that: and the attitude control comprises the steps of dynamically adjusting the shield attitude and selecting the segment splicing point position when the floating amount of the segment is large.
14. The method for comprehensively tunneling the large-diameter slurry shield in the permeable soil-rock composite stratum according to claim 13, which is characterized in that: when the deviation correction is carried out on the upper soft and lower hard strata, the principle of long-distance slow correction is followed, and the deviation correction radius is larger than the deviation radius.
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| CN109184721B (en) * | 2018-10-18 | 2020-03-17 | 上海隧道工程有限公司 | Tunneling construction method for fixing rotation direction of shield cutter head |
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| CN112360483B8 (en) * | 2020-11-12 | 2023-03-10 | 安徽唐兴装备科技股份有限公司 | Compound-motion pipe jacking machine cutter head |
| CN113006809A (en) * | 2021-04-22 | 2021-06-22 | 中交路桥建设有限公司 | Shield tunneling machine cutter head optimization method suitable for stratum rich in large-particle-size sandy pebbles |
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