CN110761797B - Construction method for shield air-pushing through mine tunnel - Google Patents
Construction method for shield air-pushing through mine tunnel Download PDFInfo
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- CN110761797B CN110761797B CN201810837581.2A CN201810837581A CN110761797B CN 110761797 B CN110761797 B CN 110761797B CN 201810837581 A CN201810837581 A CN 201810837581A CN 110761797 B CN110761797 B CN 110761797B
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- 238000010276 construction Methods 0.000 title claims abstract description 108
- 238000000034 method Methods 0.000 claims abstract description 100
- 230000005641 tunneling Effects 0.000 claims abstract description 47
- 238000005259 measurement Methods 0.000 claims abstract description 11
- 238000004140 cleaning Methods 0.000 claims abstract description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 90
- 239000010959 steel Substances 0.000 claims description 90
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 28
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- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims description 7
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- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 7
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- 230000035515 penetration Effects 0.000 claims description 5
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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
- E21D9/0607—Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining the shield being provided with devices for lining the tunnel, e.g. shuttering
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK 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
- E21D11/006—Lining anchored in the rock
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK 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
- E21D11/08—Lining with building materials with preformed concrete slabs
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK 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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- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
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Abstract
The invention discloses a construction method of a shield air-pushing mine-method tunnel, which comprises a mine-method tunnel construction stage, a guide platform construction stage, a stepping guide platform construction stage, a shield air-pushing assembled duct piece construction stage and a shield traction mine-method tunnel construction stage. The construction stage of the mine method tunnel comprises the step of mounting brackets; the guide platform construction stage comprises a guide platform base surface cleaning step, a measurement lofting step, a concrete pouring step and a finishing maintenance step; the shield empty-pushing and assembling segment construction stage comprises a shield machine empty-load pushing step, a segment assembling step, a segment back-filling grouting step and a shield connecting channel passing step; the construction stage of the shield-driven mine-method tunnel comprises a traction equipment setting step and a traction step; the construction method can ensure the splicing quality of the duct pieces, thereby ensuring the waterproof performance of the tunnel, improving the efficiency of shield empty-pushing tunneling, reducing the personnel investment and lowering the construction cost.
Description
Technical Field
The invention relates to a construction method for a shield air-pushing mine method tunnel.
Background
With the improvement of economic level, the urban construction process is accelerated, so that the number of urban underground projects and underground steel rail projects is continuously increased. The shield is a very practical tunnel construction machine, has the advantages of high efficiency, safety, environmental protection and the like, and is widely used in the construction of underground tunnels at the present stage. When the tunnel is constructed by adopting a method of 'constructing a primary support by a mine method and splicing segments by shield air pushing', the following difficulties also exist:
1. before the shield machine is pushed in the mine tunnel, a guide table of the shield machine needs to be constructed in the mine tunnel, and the construction quality of the guide table directly influences whether the shield machine can keep a good pushing posture;
2. when the shield tunneling machine is constructed 25m before reaching the mine method tunnel, along with the gradual reduction of rock soil in front of the cutter head, the disturbance of the shield tunneling machine to the rock mass in front and the positions of the interface of the mine method tunnel section and the shield section is gradually increased, so that if the shield tunneling parameters are not appropriate, the shield cannot smoothly reach the mine method tunnel section;
3. the resistance encountered by the shield tunneling machine when sliding on the guide table is small, and the extrusion force between the segments can not meet the design requirement, so that the waterproof property of the tunnel is reduced, and water leakage is easy to occur between segment rings;
4. if the grouting amount is too large, cement mortar can be caused to flow backwards to the front of the cutter head, and the consolidated pea gravel pile body can cause the whole shield machine to turn over when the cutter head rotates; if the grouting amount is too small, the back grouting effect cannot be achieved, and the duct piece cannot be stabilized in time and the waterproof effect cannot be achieved.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a construction method of a shield empty-pushing mine method tunnel, which can ensure the splicing quality of segments, thereby ensuring the sealing performance of the tunnel, improving the efficiency of shield empty-pushing tunneling, reducing the personnel investment and lowering the construction cost.
The purpose of the invention is realized as follows: a construction method of a shield empty-pushing mine method tunnel is used for construction between two subway stations, a left line and a right line are arranged between the two subway stations, and an open cut section, a first shield section, a mine method tunnel section and a second shield section are sequentially arranged between a small mileage end and a large mileage end; an intermediate vertical shaft is arranged at the junction of the mine method tunnel section and the second shield section; the shield machine enters a first shield section from an end shield well of the open cut section for normal tunneling, receives in the mine tunnel, performs shield air-pushing assembly on segments at the initial section of the mine tunnel, is pulled through the subsequent section of the mine tunnel, and then receives and hoists out in a middle vertical shaft; the shield machine normally tunnels from a large-mileage end to a small-mileage end in a second shield section, and then is hoisted out in a middle vertical shaft; constructing according to the sequence of the left line at the front and the right line at the back;
the construction method comprises a mine method tunnel construction stage, a guide platform construction stage, a stepping guide platform construction stage, a shield air-pushing assembled duct piece construction stage and a shield traction mine method tunnel construction stage;
the construction stage of the mine method tunnel comprises the following steps:
(1) excavating by adopting a drilling and blasting method; firstly, manually excavating the upper half part of a tunnel by using an air pick, erecting a grid steel frame and installing a small advanced guide pipe, excavating the lower half part of the tunnel by using weak blasting, and immediately performing primary support construction after excavation; initial support parameters: a grid steel frame is adopted, and a layer of reinforcing mesh is arranged on the outer side of the section; concrete with a spray strength rating of C25; the arch part is provided with a small advanced conduit;
(2) when the self-stability of surrounding rocks is better and the water seepage amount is smaller, the early small duct grouting is carried out on the side ring of the section of the tunnel besides the grid steel frame in the primary support at the position 5m before the shield is penetrated; when the self-stability of the surrounding rock is poor and the water seepage amount is large, a grid steel frame is adopted for primary support, advanced small conduit grouting is carried out on a tunnel section edge ring, full-section net hanging and grouting are adopted, and full-section grouting reinforcement water plugging is carried out on a tunnel face when necessary;
(3) reinforcing and grouting cement mortar on the back of a segment at the tail part of the shield by 5m before the shield enters a tunnel segment of a mine method; erecting the last grid steel frame of the mine tunnel section at a position 20cm behind the shield to the head, and arranging a sand flowing prevention device at a position 40cm in front of the shield to the head; welding two layers of steel wire meshes with fiber interlayers in between on a grid steel frame or an anchor rod;
the guide platform construction stage is the construction in a tunnel section by a mine method, and comprises the steps of cleaning a base surface of a guide platform, measuring and lofting, pouring concrete and finishing and maintaining;
the section of the guide platform is groove-shaped and is within 60 degrees of the bottom of the mine tunnel, two sides of the guide platform are inclined trapezoidal piers, the two trapezoidal piers are respectively located at 4-point and 8-point positions of the vertical surface of the mine tunnel, the outer side waists of the two trapezoidal piers are horizontally and symmetrically provided with embedded parts, and the upper bottom surfaces of the two trapezoidal piers are respectively embedded with a steel rail as a guide rail of the traction shield machine;
when the step of measuring and lofting is carried out, firstly measuring and lofting the center line of the tunnel, taking every 10m as a construction section, measuring and lofting a section every 2m, and laying 5 control piles on each section;
when the concrete pouring step is carried out, the pouring sequence is that the bottom is arranged firstly and then the two sides are arranged, the concrete slump is 10-12 cm, the flatness requirement after forming is within +/-1 cm, and the concrete strength grade is C25;
when the step of finishing and maintaining is carried out, after concrete pouring is finished, manually and timely troweling and finishing, and watering and maintaining for 14 days;
the construction stage of the walking guide table comprises the following steps;
(1) when the shield cutter head reaches 100m away from the junction section of the mine tunnel, performing primary contact measurement, rechecking the positions of a tunnel portal and a guide table, and determining the through posture of the shield machine, wherein the vertical posture is 10mm higher than the guide table;
(2) the shield tunneling speed is gradually slowed down to 20mm/min, the thrust is gradually reduced, the soil body at the opening of the hole is slowly and uniformly cut, and synchronous grouting is enhanced, so that the segment is full after being separated from the tail of the shield;
when the shield reaches 10m from the junction section of the mine tunnel, injecting low-strength cement slurry from the advanced grouting hole of the shield body to fill the back clearance of the shield body, and continuing tunneling when the cement slurry is initially set;
(3) when a shield cutter head reaches 5m away from the junction section of a mine tunnel, injecting low-strength cement slurry through a shield advanced grouting hole to fill a back gap of a shield body, wherein the thrust is 460-600 t, the penetration is 1.6 mm/r, the torque is less than or equal to 1500kNm, the tunneling speed is less than or equal to 15mm/min, and the rotation speed of the cutter head is 1.2-1.3 r/min;
(4) when the shield cutter head reaches 2m away from the junction section of the mine tunnel, the shield machine temporarily stops tunneling, and bentonite is injected through the advanced grouting hole of the shield body to fill the back gap of the shield body;
(5) after the shield machine breaks the boundary section of the mine tunnel, the shield cutter head stops rotating and stops at a corresponding position, the propelling is suspended, and the ballast blocks falling into the end of the mine tunnel are cleaned by manual assistance, so that the shield machine is prevented from deviating in the process of loading the guide table; before a guide table is arranged on a shield tunneling machine, edge diameter-protecting hobs with a cutterhead contacting with the surface of the guide table are disassembled, and meanwhile, protective steel plates with the thickness of 5cm are additionally arranged on the front shield body, the middle shield body and the rear shield body of the shield tunneling machine corresponding to steel rails on the guide table;
(6) continuously advancing the shield tunneling machine after the shield tunneling machine is arranged on the guide table, pausing until the 2 nd shield tail brush reaches the boundary section of the mine tunnel, and resuming tunneling after the double-fluid slurry synchronously injected behind the segments is solidified;
the shield empty-pushing and assembling segment construction stage comprises a shield machine empty-load pushing step, a segment assembling step, a segment back-filling step and a segment back-filling grouting step;
when the no-load propelling step of the shield machine is carried out, the propelling speed is 15-40 mm/min, the propelling speed after proficiency is 60-85 mm/min, the total thrust is 300-400 t, and the pressure of a lower oil cylinder is greater than that of an upper oil cylinder;
when the segment assembling step is carried out, the installation mode of the segment is the same as that of the first shield segment when the shield tail passes through the junction surface of the mine tunnel; after the shield tail passes through a tunnel interface of a mine method, the duct pieces are installed in a bilateral symmetry mode from the bottom of the tunnel, the standard blocks are installed firstly, the adjacent blocks are installed in sequence, and finally the capping blocks are installed; after the segment is mounted in place, the segment is timely stretched out of a propulsion oil cylinder at a corresponding position to tightly push the segment, and then a segment mounting machine is moved away;
when the segment back lining backfilling step is carried out, pea gravel is sprayed in a gap between a segment ring and a primary support while the shield tunneling machine is pushed forwards; before filling, a gap between the shield cutter head and the primary support is plugged by bagged gravels, the filling mode is that the position ten meters before the cutter head is backfilled to the height of 1/3 of a tunnel section, the two sides of a notch ring are built to the height of 2/3 of the tunnel section by sand bags every three rings, and then the gap outside the shield body is filled by a blow filling method from inside to outside and from bottom to top; granite with the particle size of 5-10 mm is adopted as the pea gravel, and the injection pressure is 0.25-0.3 Mpa;
when the step of filling and grouting the back of the duct piece is carried out, cement mortar or double-liquid slurry is synchronously injected when the pea gravel is sprayed, wherein the cement mortar is mixed with the fly ash, the bentonite, the sand and the water in a ratio of 1: 3.5: 0.8: 4: 3.7; grouting pressure is 0.1-0.2 Mpa; the initial setting time of cement mortar is 4h, and the final setting time is 8 h;
the construction stage of the shield-driven mine-method tunnel comprises a traction equipment setting step and a traction step;
the traction equipment comprises an automatic continuous pushing device, two counter-force supports and two anchoring supports; the automatic continuous pushing device comprises two continuous pushing jacks, two pump stations and a main control console; each continuous pushing jack is formed by connecting a front jack and a rear jack in series; each pump station corresponds to a continuous pushing jack and consists of a hydraulic system and a control circuit system; the main control console is electrically connected with the two pump stations;
when the traction equipment is arranged, the two counter-force supports are symmetrically arranged on an embedded part of a guide table in the tunnel by the mine method; each counter-force support is respectively provided with a continuous pushing jack, and the two pump stations and the main control console are placed between the two continuous jacks; the two anchoring supports are welded at the 4-point position and the 8-point position of the inner ring of the protective steel plate at the front end of the cutter head of the shield tunneling machine in a one-to-one correspondence manner;
the drawing step includes the following steps:
(1) the traction steel strands are blanked in equal length, each strand is 40m long, and 8 strands are rotated left and right;
(2) penetrating traction steel stranded wires, penetrating 8 traction steel stranded wires on each continuous jacking jack, and respectively rotating left and right 4 traction steel stranded wires in a staggered manner; one end of a traction steel strand is inserted into the tail part through hole of the rear jack, penetrates through the clamp holder on the rear jack, then is inserted into the tail part through hole of the front jack and is clamped by the clamp holder of the front jack, and the other end of the traction steel strand is fixed on the corresponding anchoring support by using a tool anchor and a tool clamping piece;
(3) pre-tightening the traction steel strand, namely pulling the traction steel strand by hand with a hand to make the radian of the traction steel strand basically consistent, and then integrally pre-tightening by using a continuous pushing jack;
(4) after the shield machine is dragged to reach a preset position, continuously pushing the jack to return, taking out the clamping piece of the clamp holder, loosening the fixed end pressing plate, withdrawing the clamping piece, and drawing the steel strand out of the tensioning end;
(5) after the traction of the shield machine reaches a preset position, the two counter-force supports are dismantled, moved to the next preset position and welded firmly, and then the continuous pushing jack is installed on the counter-force supports and adjusted to enter the next traction cycle.
In the construction method for the shield air-pushing through the mine tunnel, the small duct grouting parameters are advanced when the mine tunnel is constructed, wherein the diffusion radius is 1.0-1.5 m; the final pressure of the grouting is 1.5 times of hydrostatic pressure; the reinforcement range is 5m along the longitudinal length of the line; the slurry gelling time is 50-120 s; grouting speed is 20-40L/min; the grouting mode is full-hole one-time grouting.
In the construction method of the shield air-assisted mining method tunnel, when the construction stage of the mine method tunnel is carried out, advanced geological forecast is carried out, an advanced horizontal drilling method is adopted, 5 exploration holes are arranged in each cycle and are respectively arranged at the upper part, the lower part, the left part, the right part and the middle part of the section of the tunnel, and the depth of each exploration hole is 10 m; and (3) performing link measurement of a shield starting well and a shield receiving well by adopting a gyro orientation method, transmitting the link measurement from the outside to the inside of the tunnel, and performing reinforced retest by adopting the gyro orientation method when the shield end is 100m away from the side of the tunnel of the mining method, wherein the butting deviation of two ends is adjusted by excavating the mining method and tunneling the shield.
The construction method of the shield air-pushing mine-method tunnel comprises a bracket mounting step during the construction stage of the mine-method tunnel, wherein after primary support construction is completed, a pair of brackets are symmetrically mounted at two waist positions in the middle of the mine-method tunnel, a pair of brackets is mounted at every 5 rings from the receiving end of the mine-method tunnel, each pair of brackets is fixed by 12 bolts, and the bolts are anchored in the primary support and a rock mass.
In the construction method of the shield empty-pushing mining method tunnel, when the segment assembling construction stage is carried out, a segment ring is supported on a primary support by penetrating a group of special supporting rods through the hoisting holes of the segments after coming out of the shield tail, and the central axis of the segment ring is adjusted through the threads on the supporting rods; each five-ring pipe piece adopts a group of special supporting rods to support one ring pipe piece, then two legs of a group of U-shaped reinforcing steel bars are welded with clamping pieces on longitudinal connecting bolts from longitudinal bolt hand holes of adjacent pipe piece rings, and the supporting rods are led out from the ring bolts through backing plate connecting pieces and then welded on the waist of the U-shaped reinforcing steel bars; a group of U-shaped steel bars are all arranged at the same position of the upper half part of the pipe sheet ring.
In the construction method of the shield air-assisted mining method tunnel, after the segment back filling and grouting step, a shield connection channel passing step is also performed, and the shield connection channel passing step comprises the following steps:
(1) before the shield machine reaches the communication channel, fixing two I-beams on the communication channel, wherein the heights of the two I-beams are respectively aligned with the 3-point position and the 9-point position of the shield machine; piling up the communication channel by 1000mm by using a sand bag; fixing a steel plate on the two side walls of the communication channel by using expansion bolts respectively, welding an H-shaped steel on each steel plate, making three inclined struts on the outer side of the H-shaped steel, and welding one side of each inclined strut with the H-shaped steel and fixing the other side of each inclined strut with the tunnel;
(2) when the shield machine passes through a crossing of a communication channel, after the segment rings are assembled and separated from a shield tail, the segment rings are punched between the segment rings and a guide platform and between the segment rings and H-shaped steel on one side close to the communication channel by using wood wedges;
(3) when the shield constructs the machine and crosses the contact passageway, only spray pea gravel in the one side of keeping away from the contact passageway, shift the slip casting point to the left side simultaneously, when the thick liquid is still poor 100mm and sand bag top parallel and level, stop synchronous slip casting.
In the construction method of the shield empty-pushing mine-method tunnel, when the segment back filling grouting step is carried out and double-fluid slurry is injected, two synchronous grouting pipes are respectively used for grouting at hoisting holes at the 5 th ring 4 point and the 12 th ring at the tail of the shield; and (3) grouting hoisting holes at 1 point and 15 points near the 10 th ring behind the shield tail by using the other two synchronous grouting pipes.
In the construction method of the shield air-pushing mine-method tunnel, after the step of segment back filling and grouting is carried out, if the top filling of the segment ring is not compact enough, secondary grouting reinforcement is carried out, and cement mortar or double-liquid slurry is adopted as a secondary grouting material; mixing ratio of double slurries: the water cement ratio is 0.9-1, and the cement ratio to the water glass ratio is 1: 1; when double-liquid slurry is injected, 4 holes are injected in each ring, namely the top, the two waists and the arch bottom, and the same ring of pipe pieces are injected according to the principle of 'arch top first, two waists later and two waists symmetrical'; injecting pure cement slurry, mixing and injecting after 1min, and increasing the concentration of water glass when finishing the hole; waiting for 5-10 minutes after grouting in one hole is finished, then opening the grouting hole, dredging and checking the injection effect, and if the water is large, injecting the water again until the hole is ended when less water flows out; the pressure of the secondary grouting is 0.1-0.2 Mpa.
The construction method of the shield air-pushing mine tunnel has the following characteristics:
1. the groove-shaped guide platform is adopted, so that the construction is simple and convenient, the construction speed is high, the quality is easier to guarantee, and especially for the curve section of the tunnel, the risks of the shield machine inclining and the shield body clamping of the main structure of the tunnel can be reduced. In the stage of guide table construction, strict measurement is carried out to control the accuracy of the guide table, so that the shield machine can keep a good propulsion attitude, the splicing quality of the segments is ensured, and the expected waterproof effect is achieved;
2. reasonable tunneling parameters are set when the shield machine reaches 25m before the mine tunnel, so that the shield machine can smoothly reach the mine tunnel section;
3. the bracket is arranged or a proper amount of pea stones are accumulated in the mine tunnel and are continuously supplemented, so that sufficient counter force is provided for the air thrust of the shield machine, the shield attitude can be better controlled, the extrusion force between the pipe pieces reaches the design requirement in the thrust process of the shield machine, and the sealing performance of the tunnel is ensured; the construction speed is high, and the construction conditions of mine tunnel penetration limit, grouting and slurry leakage and the like in the shield advancing process can be directly observed;
4. in the shield empty-pushing assembling segment construction stage, the grouting amount and the grouting pressure are reasonably controlled, the assembling quality of the segments is ensured, and the axis deviation of the formed tunnel is controlled; meanwhile, the propelling attitude of the shield machine can be ensured.
Drawings
Fig. 1 is a schematic structural view of a bracket installed in a mine-method tunnel in the construction method for shield tunneling through the mine-method tunnel according to the present invention;
fig. 2 is a schematic structural view of a guide table constructed in a mine-method tunnel in the construction method of the shield air-thrust mine-method tunnel of the present invention;
FIG. 3 is a schematic structural diagram of a pipe sheet supporting in the construction method of the shield air-assisted mine tunnel of the present invention;
FIG. 4 is a diagram showing a state of segment back-filling grouting in the construction method of the shield tunneling empty-pushing mining method tunnel according to the present invention;
fig. 5 is a diagram showing a state in which shield tunneling through a communication passage is performed in the construction method of the shield empty-pushing mine-method tunnel according to the present invention;
fig. 6 is a diagram showing a state in which the shield machine is pulled through the mine tunnel in the construction method in which the shield machine is pushed through the mine tunnel.
Detailed Description
The invention will be further explained with reference to the drawings.
The construction method of the shield empty-pushing mine-method tunnel is used for construction between two subway stations, and a left line and a right line are arranged between the two subway stations; the interval is sequentially an open cut section, a first shield section, a mining tunnel section and a second shield section from a small mileage end to a large mileage end; an intermediate vertical shaft is arranged at the junction of the mine method tunnel section and the second shield section; the shield machine enters a first shield section from an end shield well of the open cut section for normal tunneling, receives in the mine tunnel, performs shield air-pushing assembly on segments at the initial section of the mine tunnel, is pulled through the subsequent section of the mine tunnel, and then receives and hoists out in a middle vertical shaft; the shield machine normally tunnels from a large-mileage end to a small-mileage end in a second shield section, and then is hoisted out in a middle vertical shaft; construction according to the sequence of the left line at the front and the right line at the back
The construction method comprises a mining method tunnel construction stage, a guide platform construction stage, a stepping guide platform construction stage, a shield air-pushing assembled duct piece construction stage and a shield traction mine method tunnel construction stage;
when a mine method tunnel construction stage is carried out, advanced geological prediction is carried out, an advanced horizontal drilling method is adopted, 5 exploration holes are arranged in each cycle and are respectively arranged at the upper part, the lower part, the left part, the right part and the middle part of a tunnel section, and the depth of each exploration hole is 10 m; performing link measurement of a shield starting well and a shield receiving well by adopting a gyro orientation method, transmitting the link measurement from the outside to the inside of the tunnel, and performing reinforced retest by adopting the gyro orientation method when the shield end is 100m away from the tunnel side of the mining method, wherein the butt joint deviation of two ends is adjusted by excavating by the mining method and two sides of shield tunneling so as to ensure the penetration precision;
the construction stage of the mine tunnel comprises the following steps:
(1) excavating by adopting a drilling and blasting method; firstly, manually excavating the upper half part of a tunnel by using an air pick, erecting a grid steel frame and installing a small advanced guide pipe, excavating the lower half part of the tunnel by using weak blasting, and immediately performing primary support construction after excavation;
initial support parameters: a main bar grating steel frame with the diameter phi of 25mm is adopted, the distance is 750mm, a layer of reinforcing mesh bound by 8mm round steel bars is arranged on the outer side of the section, and the distance between two transverse and vertical vertically intersected reinforcing bars is 150 mm; concrete with a spray strength rating of C25; the arch part is provided with a small advanced conduit, the small advanced conduit adopts a common water gas pipe with phi 42 multiplied by 3.25mm, the annular distance is 0.3m, and the length is 5 m;
leading the small conduit grouting parameters, wherein the diffusion radius is 1.0-1.5 m; the final pressure of the grouting is 1.5 times of hydrostatic pressure; the reinforcement range is 5m along the longitudinal length of the line; the slurry gelling time is 50-120 s; grouting speed is 20-40L/min; the grouting mode is full-hole one-time grouting;
(2) when the self-stability of surrounding rocks is better and the water seepage amount is smaller, the support adopts a grid steel frame and a tunnel section edge ring is also subjected to advanced small duct grouting 5m before the shield is penetrated; when the self-stability of the surrounding rock is poor and the water seepage amount is large, the support is supported by a grid steel frame, the side ring of the section of the tunnel is also subjected to advanced small conduit grouting, full-section net hanging grouting is adopted, and full-section grouting, reinforcing and water plugging are performed on the tunnel face when necessary;
(3) reinforcing and grouting cement mortar on the back of a segment at the tail part of the shield by 5m before the shield enters a tunnel segment of a mine method; erecting the last grid steel frame of the mine tunnel section at a position 20cm behind the shield to the head, and arranging a sand flowing prevention device at a position 40cm in front of the shield to the head; welding two layers of steel wire meshes which have enough rigidity and sandwich a fiber interlayer on a grid steel frame or an anchor rod;
(4) after the primary support construction is completed, a pair of corbels 10 are symmetrically arranged at two waist positions in the middle of the mine tunnel to provide a reaction force when the shield tunneling machine 100 is propelled, a pair of corbels 10 are arranged at every 5 rings from the receiving end of the mine tunnel, each pair of corbels 10 is fixed by 12 bolts 11, and the bolts 11 are anchored in the primary support 200 and a rock body (see fig. 1).
The guide platform construction stage is the construction in the tunnel section of the mining method, and comprises the steps of cleaning the base surface of the guide platform, measuring and lofting, pouring concrete and finishing and maintaining;
the section of the guide platform 300 is groove-shaped and is within 60 degrees of the bottom of the mine tunnel, two sides of the guide platform are inclined trapezoidal piers, the two trapezoidal piers are respectively located at 4-point position and 8-point position of the vertical surface of the mine tunnel, the outer side waist of the two trapezoidal piers is horizontally and symmetrically provided with embedded parts 301, and the upper bottom surfaces of the two trapezoidal piers are respectively embedded with a steel rail 400 which is used as a guide rail of a traction shield machine (see figure 2);
when the step of measuring and lofting is carried out, firstly measuring and lofting the center line of the tunnel, taking every 10m as a construction section, measuring and lofting a section every 2m, and laying 5 control piles on each section;
when the concrete pouring step is carried out, the pouring sequence is that the bottom is arranged firstly and then the two sides are arranged, the concrete slump is 10-12 cm, the flatness is +/-1 cm after the concrete is formed, and the concrete strength grade is C25;
and in the finishing and maintaining step, after concrete pouring is finished, manually and timely troweling and finishing, and watering and maintaining for 14 days.
The construction stage of the walking guide table comprises the following steps;
(1) when the shield cutter head reaches 100m away from the junction section of the mine tunnel, performing primary contact measurement, rechecking the positions of the tunnel portal and the guide platform, and determining the through posture of the shield machine, wherein the vertical posture is 10mm higher than the guide platform, so that the shield machine can smoothly break the tunnel portal and step into the guide platform;
(2) the shield tunneling speed is gradually slowed down to 20mm/min, the thrust is gradually reduced, the soil body at the opening of the hole is slowly and uniformly cut, and synchronous grouting is enhanced, so that the segment is full after being separated from the tail of the shield;
when the shield reaches 10m from the junction section of the mine tunnel, injecting low-strength cement slurry from the advanced grouting hole of the shield body to fill the back clearance of the shield body, and continuing tunneling when the cement slurry is initially set;
(3) when a shield cutter head reaches 5m away from the junction section of a mine tunnel, injecting low-strength cement slurry through a shield advanced grouting hole to fill a back gap of the shield, wherein the shield adopts a thrust of 460-600 t, a penetration of 1.6 mm/r, a torque of less than or equal to 1500kNm, a speed of less than or equal to 15mm/min and a cutter head rotation speed of 1.2-1.3 r/min, the concentration of double-fluid slurry (cement slurry and water glass) is properly increased at the back of a duct piece in the tunneling process, and the grouting pressure is controlled to be less than or equal to 0.4 MPa; ensuring compact filling, and simultaneously enhancing ground settlement above the tunnel and monitoring of buildings (structures);
(4) when the shield cutter head reaches 2m away from the junction section of the mine tunnel, the shield machine temporarily stops tunneling, and bentonite is injected through the shield body advanced grouting hole to fill the back gap of the shield body, so that the forward channeling of synchronous grouting is avoided, and the full grouting of synchronous double-fluid slurry is ensured; controlling the rotating speed of the screw machine to ensure that the residue soil in the soil bin can be discharged in time and keep the bin empty;
(5) after the shield machine breaks the boundary section of the mine tunnel, the shield cutter head stops rotating and stops at a corresponding position, the propelling is suspended, and the ballast blocks falling into the end of the mine tunnel are cleaned by manual assistance, so that the shield machine is prevented from deviating in the process of loading the guide table; because the outer diameter of the cutter head of the shield machine is larger than the outer diameter of the shield body, the edge diameter-protecting hob of which the cutter head is in contact with the guide table surface is required to be disassembled before the guide table on the shield machine, the damage of the steel rail and the concrete pre-embedded on the guide table by the cutter is avoided when the shield machine is propelled on the guide table, and meanwhile, the protection steel plates with the thickness of 5cm are additionally arranged on the front, middle and rear shield bodies of the shield machine corresponding to the steel rail positions of the guide table, so that the shield body is prevented from being worn due to long-distance air.
(6) Continuously advancing the shield tunneling machine after the shield tunneling machine is arranged on the guide table, pausing until the 2 nd shield tail brush reaches the boundary section of the mine tunnel, and resuming tunneling after the double-fluid slurry synchronously injected behind the segments is solidified; and during synchronous grouting, lower grouting pressure is adopted, the injection flow is reduced, and intermittent injection is performed if necessary, so that the plugging and water stopping effects are achieved.
The shield empty-pushing and assembling segment construction stage comprises a shield machine empty-load pushing step, a segment assembling step, a segment back-lining backfilling step, a segment back-filling grouting step and a shield connecting channel passing step;
when the no-load propelling step of the shield machine is carried out, the propelling speed is 15-40 mm/min, the propelling speed after proficiency is 60-85 mm/min, the total thrust is 300-400 t, and the pressure of a lower oil cylinder is greater than that of an upper oil cylinder;
when the segment assembling step is carried out, the shield tail passes through the front of the junction surface of the mine tunnel, and the segment mounting mode is the same as that of the first shield segment; after the shield tail passes through a tunnel interface of a mine method, the duct pieces are installed in a bilateral symmetry mode from the bottom of the tunnel, the standard blocks are installed firstly, the adjacent blocks are installed in sequence, and finally the capping blocks are installed; after the segment is mounted in place, the segment is timely stretched out of a propulsion oil cylinder at a corresponding position to tightly push the segment, and then a segment mounting machine is moved away;
after the pipe sheet ring 500 is separated from the shield tail, a group of special supporting bolts 50 penetrate through the hoisting holes of the pipe sheets to be supported on the primary support 200, the pipe sheet ring 500 is supported, and the central axis of the pipe sheet ring is adjusted through the threads on the supporting bolts 50; ensuring that the design axis of the pipe is consistent with the design axis of the tunnel, and supporting one ring of pipe pieces by a group of special supporting rods for each five-ring of pipe pieces (see figure 3); then, two legs of a group of U-shaped steel bars (four) are welded with clamping pieces on the longitudinal connecting bolts from longitudinal bolt hand holes of adjacent pipe sheet rings 500, and the supporting rods 50 are led out from the ring direction through the backing plate connecting pieces and then welded on the waist of the U-shaped steel bars; a group of U-shaped steel bars are all arranged at the same position of the upper half part of the tube sheet ring 500;
when the step of segment backing backfilling is carried out, the shield machine 100 is pushed forwards, and meanwhile, the bean gravel 600 is sprayed and filled in the gap between the segment ring 500 and the primary support 200, the filling mode is that the position ten meters ahead of the cutter head is backfilled to the height of 1/3 (shown in figure 2) of the tunnel section, the two sides of the notch ring are built to the height of 2/3 of the tunnel section by sand bags every three rings, enough counter force is provided for shield air pushing, and the filling amount of the bean gravel of each ring segment is 7.36m3Granite with the particle size of 5-10 mm is adopted, the injection pressure is 0.25-0.3 Mpa, and the diameter of the injection pipe 60 is 50 mm; the pipe for conveying the pea gravel is fixed on the shield cutter head by an iron wire, and the length of the pipe exceeds 70cm of the shield machine; the injection machine is arranged 8-10 m in front of the shield cutter head, the gap between the shield cutter head and the primary support is blocked by bagged gravels before filling, and then the gap outside the shield body is filled according to a blow filling method from inside to outside and from bottom to top (see figure 4);
when the step of segment back filling and grouting is carried out, cement mortar or double-liquid slurry is synchronously injected when the pea gravel is sprayed, wherein the cement mortar is prepared from cement, fly ash, bentonite, sand and water, and the ratio of the cement mortar to the fly ash to the bentonite to the sand to the water is 1: 3.5: 0.8: 4: 3.7; grouting pressure is 0.1-0.2 Mpa; the initial setting time of cement mortar is 4h, and the final setting time is 8 h; when injecting double-liquid slurry, respectively injecting slurry into hoisting holes at the 4 th ring position and the 12 th ring position of the shield tail by two synchronous grouting pipes, and respectively injecting slurry into hoisting holes at the 1 st ring position and the 15 th ring position near the 10 th ring position behind the shield tail by the other two synchronous grouting pipes;
if the top of the segment ring is not densely filled, secondary grouting reinforcement is carried out, and cement mortar or double-liquid slurry is adopted as a secondary grouting material; mixing ratio of double slurries: the water cement ratio is 0.9-1, and the cement ratio to the water glass ratio is 1: 1; when double-liquid slurry is injected, 4 holes are injected in each ring, namely the top, the two waists and the arch bottom, and the same ring of pipe pieces are injected according to the principle of 'arch top first, two waists later and two waists symmetrical'; injecting pure cement slurry, mixing and injecting after 1min, and increasing the concentration of water glass when finishing the hole; waiting for 5-10 minutes after grouting in one hole is finished, then opening the grouting hole, dredging and checking the injection effect, and if the water is large, injecting the water again until the hole is ended when less water flows out; the pressure of the secondary grouting is 0.1-0.2 Mpa;
the step of shield passing through the communication channel comprises the following procedures:
(1) before the shield machine reaches the communication channel 501, two I-beams 502 are fixed on the communication channel 501, and the heights of the two I-beams 502 are respectively flush with the 3-point position and the 9-point position of the shield machine; the communication channel 501 is piled up 1000mm high using a sandbag 503; fixing a steel plate with the thickness of 250mm multiplied by 150mm multiplied by 5mm on the two side walls of the communication channel 501 by using expansion bolts respectively, welding an H-shaped steel on each steel plate, making three inclined struts on the outer side of the H-shaped steel, welding one side of each inclined strut with the H-shaped steel, and fixing one side of each inclined strut with the tunnel;
(2) when the shield machine passes through the crossing of the communication channel 501, after the segments are assembled and separated from the tail of the shield, the segments are punched between the segment ring 500 and the guide platform 300 and between the segment ring and the H-shaped steel by using wood wedges 504 at one side close to the communication channel 501, so that the segment ring 500 is prevented from sinking and laterally moving (see fig. 5);
(3) when the shield constructs the machine and crosses the contact passageway, only spray pea gravel in the one side of keeping away from the contact passageway, shift the slip casting point to the left side simultaneously, when the thick liquid is still poor 100mm and sand bag top parallel and level, stop synchronous slip casting.
The construction stage of the shield traction mine-crossing tunnel comprises a traction equipment setting step and a traction step;
the traction equipment comprises an automatic continuous pushing device, two counter-force supports 30 and two anchoring supports 40; the automatic continuous pushing device comprises two continuous pushing jacks 20, two pump stations and a main control console; each continuous pushing jack is formed by connecting a front jack and a rear jack in series; each pump station corresponds to a continuous pushing jack and consists of a hydraulic system and a control circuit system; the main control console is electrically connected with the two pump stations; a starting key, an automatic key and a forward jacking key are arranged on a panel of the main control console;
when the traction equipment setting step is carried out, the two reaction force support bases 30 are symmetrically arranged on the embedded part 301 of the guide table 300 of the mine tunnel; each counter-force support 30 is respectively provided with one continuous pushing jack 20, a pump station and a main control console are placed between the two continuous pushing jacks, in order to ensure the synchronization and the consistent output of the two continuous pushing jacks in the translation process, oil inlets of a front jacking unit and an oil inlet of a rear jacking unit of the two continuous pushing jacks are respectively connected in parallel, and oil return ports are respectively independent; the two anchoring supports 40 are welded at the 4-point position and the 8-point position of the inner ring of the protective steel plate at the front end of the cutter head of the shield tunneling machine in a one-to-one correspondence manner (see fig. 6);
the traction step comprises the following steps:
(1) the traction steel strands are blanked in equal length, each strand is 40m long, and 8 strands are rotated left and right;
(2) penetrating traction steel strands, penetrating 8 traction steel strands on each continuous jacking jack, respectively rotating 4 traction steel strands in a left direction and a right direction, arranging the traction steel strands in a staggered manner, penetrating one end of each traction steel strand into a tail penetrating hole of a rear jack, penetrating through a clamp holder on the rear jack, penetrating into a tail penetrating hole of the front jack, clamping by the clamp holder of the front jack, and fixing the other end of each traction steel strand on a corresponding anchoring support 40 by using a tool anchor and a tool clamping piece;
(3) pre-tightening the traction steel strand, namely pulling the traction steel strand by hand with a hand to make the radian of the traction steel strand basically consistent, and then integrally pre-tightening by using a continuous pushing jack;
(4) the keys are operated on the panel of the main control console according to the sequence of starting → automatic → advancing, so that the shield machine can be automatically and continuously translated;
(5) after the shield machine is pulled along a guide rail on a guide table of the tunnel to reach a preset position, continuously pushing a jack to return, and drawing out a traction steel strand; and (3) dismantling the two counter-force supports, moving to the next preset position, firmly welding, installing the continuous pushing jack on the counter-force supports, adjusting the continuous pushing jack, entering the next traction cycle, and finishing traction by multiple cycles, wherein each cycle is 25 m.
The above embodiments are provided only for illustrating the present invention and not for limiting the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and therefore all equivalent technical solutions should also fall within the scope of the present invention, and should be defined by the claims.
Claims (8)
1. A construction method of a shield empty-pushing mine method tunnel is used for construction between two subway stations, a left line and a right line are arranged between the two subway stations, and an open cut section, a first shield section, a mine method tunnel section and a second shield section are sequentially arranged between a small mileage end and a large mileage end; an intermediate vertical shaft is arranged at the junction of the mine method tunnel section and the second shield section; the shield machine enters a first shield section from an end shield well of the open cut section for normal tunneling, receives in the mine tunnel, performs shield air-pushing assembly on segments at the initial section of the mine tunnel, is pulled through the subsequent section of the mine tunnel, and then receives and hoists out in a middle vertical shaft; the shield machine normally tunnels from a large-mileage end to a small-mileage end in a second shield section, and then is hoisted out in a middle vertical shaft; constructing according to the sequence of the left line at the front and the right line at the back;
the construction method comprises a mine method tunnel construction stage, a guide platform construction stage, a stepping guide platform construction stage, a shield air-pushing assembled duct piece construction stage and a shield traction mine method tunnel construction stage; it is characterized in that the preparation method is characterized in that,
the construction stage of the mine method tunnel comprises the following steps:
(1) excavating by adopting a drilling and blasting method; firstly, manually excavating the upper half part of a tunnel by using an air pick, erecting a grid steel frame and installing a small advanced guide pipe, excavating the lower half part of the tunnel by using weak blasting, and immediately performing primary support construction after excavation; initial support parameters: a grid steel frame is adopted, and a layer of reinforcing mesh is arranged on the outer side of the section; concrete with a spray strength rating of C25; the arch part is provided with a small advanced conduit;
(2) when the self-stability of surrounding rocks is better and the water seepage amount is smaller, the early small duct grouting is carried out on the side ring of the section of the tunnel besides the grid steel frame in the primary support at the position 5m before the shield is penetrated; when the self-stability of the surrounding rock is poor and the water seepage amount is large, a grid steel frame is adopted for primary support, advanced small conduit grouting is carried out on a tunnel section edge ring, full-section net hanging and grouting are adopted, and full-section grouting reinforcement water plugging is carried out on a tunnel face;
(3) reinforcing and grouting cement mortar on the back of a segment at the tail part of the shield by 5m before the shield enters a tunnel segment of a mine method; erecting the last grid steel frame of the mine tunnel section at a position 20cm behind the shield to the head, and arranging a sand flowing prevention device at a position 40cm in front of the shield to the head; welding two layers of steel wire meshes with fiber interlayers in between on a grid steel frame or an anchor rod;
the guide platform construction stage is the construction in a tunnel section by a mine method, and comprises the steps of cleaning a base surface of a guide platform, measuring and lofting, pouring concrete and finishing and maintaining;
the section of the guide platform is groove-shaped and is within 60 degrees of the bottom of the mine tunnel, two sides of the guide platform are inclined trapezoidal piers, the two trapezoidal piers are respectively located at 4-point and 8-point positions of the vertical surface of the mine tunnel, the outer side waists of the two trapezoidal piers are horizontally and symmetrically provided with embedded parts, and the upper bottom surfaces of the two trapezoidal piers are respectively embedded with a steel rail as a guide rail of the traction shield machine;
when the step of measuring and lofting is carried out, firstly measuring and lofting the center line of the tunnel, taking every 10m as a construction section, measuring and lofting a section every 2m, and laying 5 control piles on each section;
when the concrete pouring step is carried out, the pouring sequence is that the bottom is arranged firstly and then the two sides are arranged, the concrete slump is 10-12 cm, the flatness requirement after forming is within +/-1 cm, and the concrete strength grade is C25;
when the step of finishing and maintaining is carried out, after concrete pouring is finished, manually and timely troweling and finishing, and watering and maintaining for 14 days;
the construction stage of the walking guide table comprises the following steps;
(1) when the shield cutter head reaches 100m away from the junction section of the mine tunnel, performing primary contact measurement, rechecking the positions of a tunnel portal and a guide table, and determining the through posture of the shield machine, wherein the vertical posture is 10mm higher than the guide table;
(2) the shield tunneling speed is gradually slowed down to 20mm/min, the thrust is gradually reduced, the soil body at the opening of the hole is slowly and uniformly cut, and synchronous grouting is enhanced, so that the segment is full after being separated from the tail of the shield;
when the shield reaches 10m from the junction section of the mine tunnel, injecting low-strength cement slurry from the advanced grouting hole of the shield body to fill the back clearance of the shield body, and continuing tunneling when the cement slurry is initially set;
(3) when a shield cutter head reaches 5m away from the junction section of a mine tunnel, injecting low-strength cement slurry through a shield advanced grouting hole to fill a back gap of a shield body, wherein the thrust is 460-600 t, the penetration is 1.6 mm/r, the torque is less than or equal to 1500kNm, the tunneling speed is less than or equal to 15mm/min, and the rotation speed of the cutter head is 1.2-1.3 r/min;
(4) when the shield cutter head reaches 2m away from the junction section of the mine tunnel, the shield machine temporarily stops tunneling, and bentonite is injected through the advanced grouting hole of the shield body to fill the back gap of the shield body;
(5) after the shield machine breaks the boundary section of the mine tunnel, the shield cutter head stops rotating and stops at a corresponding position, the propelling is suspended, and the ballast blocks falling into the end of the mine tunnel are cleaned by manual assistance, so that the shield machine is prevented from deviating in the process of loading the guide table; before a guide table is arranged on a shield tunneling machine, edge diameter-protecting hobs with a cutterhead contacting with the surface of the guide table are disassembled, and meanwhile, protective steel plates with the thickness of 5cm are additionally arranged on the front shield body, the middle shield body and the rear shield body of the shield tunneling machine corresponding to steel rails on the guide table;
(6) continuously advancing the shield tunneling machine after the shield tunneling machine is arranged on the guide table, pausing until the 2 nd shield tail brush reaches the boundary section of the mine tunnel, and resuming tunneling after the double-fluid slurry synchronously injected behind the segments is solidified;
the shield empty-pushing and assembling segment construction stage comprises a shield machine empty-load pushing step, a segment assembling step, a segment back-filling step and a segment back-filling grouting step;
when the no-load propelling step of the shield machine is carried out, the propelling speed is 15-40 mm/min, the propelling speed after proficiency is 60-85 mm/min, the total thrust is 300-400 t, and the pressure of a lower oil cylinder is greater than that of an upper oil cylinder;
when the segment assembling step is carried out, the installation mode of the segment is the same as that of the first shield segment when the shield tail passes through the junction surface of the mine tunnel; after the shield tail passes through a tunnel interface of a mine method, the duct pieces are installed in a bilateral symmetry mode from the bottom of the tunnel, the standard blocks are installed firstly, the adjacent blocks are installed in sequence, and finally the capping blocks are installed; after the segment is mounted in place, the segment is timely stretched out of a propulsion oil cylinder at a corresponding position to tightly push the segment, and then a segment mounting machine is moved away;
when the segment back lining backfilling step is carried out, pea gravel is sprayed in a gap between a segment ring and a primary support while the shield tunneling machine is pushed forwards; before filling, a gap between the shield cutter head and the primary support is plugged by bagged gravels, the filling mode is that the position ten meters before the cutter head is backfilled to the height of 1/3 of a tunnel section, the two sides of a notch ring are built to the height of 2/3 of the tunnel section by sand bags every three rings, and then the gap outside the shield body is filled by a blow filling method from inside to outside and from bottom to top; granite with the particle size of 5-10 mm is adopted as the pea gravel, and the injection pressure is 0.25-0.3 Mpa;
when the step of filling and grouting the back of the duct piece is carried out, cement mortar or double-liquid slurry is synchronously injected when the pea gravel is sprayed, wherein the cement mortar is mixed with the fly ash, the bentonite, the sand and the water in a ratio of 1: 3.5: 0.8: 4: 3.7; grouting pressure is 0.1-0.2 Mpa; the initial setting time of cement mortar is 4h, and the final setting time is 8 h;
the construction stage of the shield-driven mine-method tunnel comprises a traction equipment setting step and a traction step;
the traction equipment comprises an automatic continuous pushing device, two counter-force supports and two anchoring supports; the automatic continuous pushing device comprises two continuous pushing jacks, two pump stations and a main control console; each continuous pushing jack is formed by connecting a front jack and a rear jack in series; each pump station corresponds to a continuous pushing jack and consists of a hydraulic system and a control circuit system; the main control console is electrically connected with the two pump stations;
when the traction equipment is arranged, the two counter-force supports are symmetrically arranged on an embedded part of a guide table in the tunnel by the mine method; each counter-force support is respectively provided with a continuous pushing jack, and the two pump stations and the main control console are placed between the two continuous jacks; the two anchoring supports are welded at the 4-point position and the 8-point position of the inner ring of the protective steel plate at the front end of the cutter head of the shield tunneling machine in a one-to-one correspondence manner;
the drawing step includes the following steps:
(1) the traction steel strands are blanked in equal length, each strand is 40m long, and 8 strands are rotated left and right;
(2) penetrating traction steel stranded wires, penetrating 8 traction steel stranded wires on each continuous jacking jack, and respectively rotating left and right 4 traction steel stranded wires in a staggered manner; one end of a traction steel strand is inserted into the tail part through hole of the rear jack, penetrates through the clamp holder on the rear jack, then is inserted into the tail part through hole of the front jack and is clamped by the clamp holder of the front jack, and the other end of the traction steel strand is fixed on the corresponding anchoring support by using a tool anchor and a tool clamping piece;
(3) pre-tightening the traction steel strand, namely pulling the traction steel strand by hand with a hand to make the radian of the traction steel strand basically consistent, and then integrally pre-tightening by using a continuous pushing jack;
(4) after the shield machine is dragged to reach a preset position, continuously pushing the jack to return, taking out the clamping piece of the clamp holder, loosening the fixed end pressing plate, withdrawing the clamping piece, and drawing the steel strand out of the tensioning end;
(5) after the traction of the shield machine reaches a preset position, the two counter-force supports are dismantled, moved to the next preset position and welded firmly, and then the continuous pushing jack is installed on the counter-force supports and adjusted to enter the next traction cycle.
2. The construction method of the shield empty-pushing mine-method tunnel according to claim 1, characterized in that, in the construction stage of the mine-method tunnel, the small guide pipe grouting parameter is advanced, wherein the diffusion radius is 1.0-1.5 m; the final pressure of the grouting is 1.5 times of hydrostatic pressure; the reinforcement range is 5m along the longitudinal length of the line; the slurry gelling time is 50-120 s; grouting speed is 20-40L/min; the grouting mode is full-hole one-time grouting.
3. The construction method of the shield empty-pushing mine-method tunnel according to claim 1, characterized in that, in the construction stage of the mine-method tunnel, advance geological forecast is firstly carried out, an advance horizontal drilling method is adopted, 5 exploration holes are arranged in each cycle and are respectively arranged at the upper part, the lower part, the left part, the right part and the middle part of the cross section of the tunnel, and the depth of each exploration hole is 10 m; and (3) performing link measurement of a shield starting well and a shield receiving well by adopting a gyro orientation method, transmitting the link measurement from the outside to the inside of the tunnel, and performing reinforced retest by adopting the gyro orientation method when the shield end is 100m away from the side of the tunnel of the mining method, wherein the butting deviation of two ends is adjusted by excavating the mining method and tunneling the shield.
4. The construction method of a shield empty push-through mine-method tunnel according to claim 1, characterized in that, when the construction stage of the mine-method tunnel is performed, the construction method further comprises a bracket installation step, after the preliminary bracing construction is completed, a pair of brackets are symmetrically installed at two waist positions in the middle of the mine-method tunnel, a pair of brackets is installed at every 5 rings from the receiving end of the mine-method tunnel, each pair of brackets is fixed by 12 bolts, and the bolts are anchored in the preliminary bracing and the rock mass.
5. The construction method of the shield empty-pushing mining method tunnel according to claim 1, characterized in that, during the shield empty-pushing assembling segment construction stage, after the segment ring comes off the shield tail, a set of special supporting rods are used to penetrate through the segment hoisting holes to be supported on the primary support, and the central axis of the segment ring is adjusted through the threads on the supporting rods; each five-ring pipe piece adopts a group of special supporting rods to support one ring pipe piece, then two legs of a group of U-shaped reinforcing steel bars are welded with clamping pieces on longitudinal connecting bolts from longitudinal bolt hand holes of adjacent pipe piece rings, and the supporting rods are led out from the ring bolts through backing plate connecting pieces and then welded on the waist of the U-shaped reinforcing steel bars; a group of U-shaped steel bars are all arranged at the same position of the upper half part of the pipe sheet ring.
6. The method of claim 1, wherein the step of back-filling and grouting the segments is followed by the step of passing through a connecting channel by a shield, and the step of passing through a connecting channel by a shield comprises the following steps:
(1) before the shield machine reaches the communication channel, fixing two I-beams on the communication channel, wherein the heights of the two I-beams are respectively aligned with the 3-point position and the 9-point position of the shield machine; piling up the communication channel by 1000mm by using a sand bag; fixing a steel plate on the two side walls of the communication channel by using expansion bolts respectively, welding an H-shaped steel on each steel plate, making three inclined struts on the outer side of the H-shaped steel, and welding one side of each inclined strut with the H-shaped steel and fixing the other side of each inclined strut with the tunnel;
(2) when the shield machine passes through a crossing of a communication channel, after the segment rings are assembled and separated from a shield tail, the segment rings are punched between the segment rings and a guide platform and between the segment rings and H-shaped steel on one side close to the communication channel by using wood wedges;
(3) when the shield constructs the machine and crosses the contact passageway, only spray pea gravel in the one side of keeping away from the contact passageway, shift the slip casting point to the left side simultaneously, when the thick liquid is still poor 100mm and sand bag top parallel and level, stop synchronous slip casting.
7. The construction method of the shield empty-pushing mine-method tunnel according to claim 1, characterized in that during the segment back-filling grouting step and during the double-fluid slurry injection, two synchronous grouting pipes are respectively grouted at hoisting holes at the 5 th ring 4 point and 12 point of the shield tail; and (3) grouting hoisting holes at 1 point and 15 points near the 10 th ring behind the shield tail by using the other two synchronous grouting pipes.
8. The construction method of the shield empty-pushing mine-method tunnel according to claim 1, characterized in that after the segment back-filling grouting step, if the top of the segment ring is not densely filled enough, secondary grouting reinforcement is performed, and the secondary grouting material adopts cement mortar or double-fluid slurry; mixing ratio of double slurries: the water cement ratio is 0.9-1, and the cement ratio to the water glass ratio is 1: 1; when double-liquid slurry is injected, 4 holes are injected in each ring, namely the top, the two waists and the arch bottom, and the same ring of pipe pieces are injected according to the principle of 'arch top first, two waists later and two waists symmetrical'; injecting pure cement slurry, mixing and injecting after 1min, and increasing the concentration of water glass when finishing the hole; waiting for 5-10 minutes after grouting in one hole is finished, then opening the grouting hole, dredging and checking the injection effect, and if the water is large, injecting the water again until the hole is ended when less water flows out; the pressure of the secondary grouting is 0.1-0.2 Mpa.
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| CN111411969A (en) * | 2020-03-31 | 2020-07-14 | 中煤第五建设有限公司 | Controlled blasting construction process for freezing section of inclined shaft |
| CN111456745A (en) * | 2020-04-10 | 2020-07-28 | 齐鲁交通发展集团有限公司 | Dragging device and dragging method for shield host in tunnel |
| CN111594199A (en) * | 2020-05-20 | 2020-08-28 | 中铁二局集团有限公司 | Construction method for wall back backfilling of double-shield TBM |
| CN113482625A (en) * | 2021-07-05 | 2021-10-08 | 石家庄铁道大学 | Rotation prevention protection method and device for pipe joints of pipe-jacking tunnel under external engineering disturbance |
| CN113931640B (en) * | 2021-10-15 | 2024-04-12 | 中国建筑第六工程局有限公司 | Construction method for shield empty pushing and starting in mine tunnel |
| CN114263469B (en) * | 2021-11-10 | 2023-11-14 | 中铁二局集团有限公司 | TBM or shield tunneling machine rapid jacking system and construction method |
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| US5755535A (en) * | 1996-08-19 | 1998-05-26 | Triad Support Systems, Inc. | Mine roof truss system and related installation method |
| CN104500082B (en) * | 2014-12-29 | 2016-09-28 | 上海市基础工程集团有限公司 | In Tunneling by mining method, shield receives construction method |
| KR101648862B1 (en) * | 2016-01-06 | 2016-08-30 | 원하종합건설 주식회사 | Under-ground pushing pipe and under-ground structure construction method therewith |
| CN205503149U (en) * | 2016-03-11 | 2016-08-24 | 中铁第一勘察设计院集团有限公司 | Special section mine method tunnel structure of circle varies from top to bottom |
| CN107130979A (en) * | 2017-05-31 | 2017-09-05 | 广州市市政工程设计研究总院 | A kind of shield sky pushes through the section of jurisdiction float Structure and construction method of Tunneling by mining method |
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