CN112412496A - Full-section advanced curtain grouting construction method for water-rich broken geological zone tunnel - Google Patents

Full-section advanced curtain grouting construction method for water-rich broken geological zone tunnel Download PDF

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Publication number
CN112412496A
CN112412496A CN202011393988.4A CN202011393988A CN112412496A CN 112412496 A CN112412496 A CN 112412496A CN 202011393988 A CN202011393988 A CN 202011393988A CN 112412496 A CN112412496 A CN 112412496A
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China
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grouting
water
drilling
hole
stopping wall
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马希平
李建军
温辉
翟建国
刘军华
杨鲜明
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China Railway 12th Bureau Group Co Ltd
Third Engineering Co Ltd of China Railway 12th Bureau Group Co Ltd
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China Railway 12th Bureau Group Co Ltd
Third Engineering Co Ltd of China Railway 12th Bureau Group Co Ltd
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Priority to CN202011393988.4A priority Critical patent/CN112412496A/en
Publication of CN112412496A publication Critical patent/CN112412496A/en
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    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/04Lining with building materials
    • E21D11/10Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
    • E21D11/105Transport or application of concrete specially adapted for the lining of tunnels or galleries ; Backfilling the space between main building element and the surrounding rock, e.g. with concrete
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/38Waterproofing; Heat insulating; Soundproofing; Electric insulating
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/001Improving soil or rock, e.g. by freezing; Injections

Abstract

The invention belongs to the technical field of tunnel construction, and particularly relates to a full-section advanced curtain grouting construction method for a tunnel in a water-rich broken geological zone. The method comprises the following steps of S100-construction preparation; s200, constructing a grout stopping wall; s300, measuring and paying off, marking hole positions, releasing the hole positions on a working surface according to the hole positions and the drilling parameters of a design drawing, and calibrating by using paint; s400, drilling holes, adjusting the elevation angle and the horizontal angle of the drill rod, moving the drilling machine, and aligning the drill bit to the marked hole position. Placing a prism at the tail end of the drill rod, and checking and adjusting the posture of the drill rod by using a total station; s500, mounting an orifice pipe; s600, advancing type sectional grouting; s700, detecting the grouting effect by drilling.

Description

Full-section advanced curtain grouting construction method for water-rich broken geological zone tunnel
Technical Field
The invention belongs to the technical field of tunnel construction, and particularly relates to a full-section advanced curtain grouting construction method for a tunnel in a water-rich broken geological zone.
Background
Along with the rapid development of economy, the demand of various regions for traffic is gradually enlarged, and in order to form a complete road traffic network, a highway is continuously developed to a mountain region, so that the construction of mountain tunnels is more and more, and the phenomena of water burst, mud burst and collapse caused by exposing a water-rich stratum in the process of the tunnel crossing a mountain are more and more common. For example, after the tunnel face of the Jilian expressway Zhongjiashan tunnel is pushed to an F2 fault, water inrush mud outburst disasters with large scale, long duration and large destructiveness occur for more than ten times, and the accumulated mud outburst amount is about 40000m3Even mountain tops above the tunnel are cracked and the ground surface collapses; water gushing phenomena of different degrees occur in tunnels such as south major girder highway HuaYingshan tunnel in Yujing Chuanjing, Jinhua super long tunnel in Kunshan highway in Guangdong province, No. 1 tunnel in Beishan highway uncovered in Guangdong province and the like.
The treatment of tunnel water burst mainly comprises a full-blocking mode and a drainage mode, and the treatment mode is closely related to the tunnel construction idea and the construction technology. In the initial stage of tunnel construction in China, water-proof curtains are formed in a certain range around a tunnel according to a main water guide channel based on a principle of 'mainly arranging rows', and a drainage system is arranged at the back of a tunnel lining. Many scholars at home and abroad verify that the grouting technology is an effective means for treating tunnel water burst by means of theoretical analysis, model test and numerical simulation; the road tunnels mentioned above all adopt grouting technology, and obtain better effect, so that the grouting technology is mature in practical engineering application.
The tunnel crack is extremely developed, a tunnel with a long section is constructed on a reverse slope, the tunnel is communicated with a surface water system smoothly, the surface ecological environment is damaged, the pumping and drainage pressure is high, and the risk of flooding a hole due to water burst is extremely high.
Disclosure of Invention
The invention aims to solve the problems and provides a full-section advanced curtain grouting construction method for a tunnel in a water-rich broken geological zone.
The invention adopts the following technical scheme: a full-section advanced curtain grouting construction method for a water-rich broken geological zone tunnel comprises the following steps of S100-construction preparation; s200, constructing a grout stopping wall; s300, measuring and paying off, marking hole positions, releasing the hole positions on a working surface according to the hole positions and the drilling parameters of a design drawing, and calibrating by using paint; s400, drilling holes, adjusting the elevation angle and the horizontal angle of the drill rod, moving the drilling machine, and aligning the drill bit to the marked hole position. Placing a prism at the tail end of the drill rod, and checking and adjusting the posture of the drill rod by using a total station; s500, mounting an orifice pipe; s600, advancing type sectional grouting; s700, detecting the grouting effect by drilling.
Step S100 takes the following approach:
s101, overhauling and maintaining the drilling machine and the grouting pump, processing a hole pipe, preparing a grouting material and carrying out a slurry test.
S102, water is led through a drain hole; before the grout stopping wall is constructed, cleaning a base to a base rock surface, flushing water at a plurality of positions in the range of a tunnel face due to the development of joint cracks of surrounding rocks, covering and sealing the tunnel face by using a waterproof plate, and collecting and dispersing water; after the pre-reinforcing measures are finished, C30 concrete is adopted to pour a 1m high concrete water retaining bank with the thickness of 40cm, and a water drainage steel pipe is embedded at the bottom of the water retaining bank to conduct water to a ditch outside the construction platform; considering that the water pressure of a water burst point on the tunnel face is large, a high-pressure gate valve, a matched flange plate and a matched high-pressure steel gasket are adopted at a pipeline joint; preparing a plurality of phi 108 steel pipes for guiding and draining the scattered water in the construction process of the grout stop wall, collecting the scattered water and then intensively draining the scattered water to ditches at two sides outside the grout stop wall.
S103, pre-reinforcing measures; in order to ensure the stability of the grout stop wall, steel bars are planted in the circumferential range of the grout stop wall, and a small advanced grouting guide pipe is implemented on the tunnel face so as to increase the anchoring force between the grout stop wall and surrounding rocks on the tunnel face; before the grout stopping wall is constructed, an excavator is adopted to cooperate with manual work to firstly clean the substrate to the rock surface, and the steel bars are planted at the bottom of the grout stopping wall and in the whole circle of primary support range. The number of the bar planting rings is two, the bar planting adopts a phi 22 cartridge anchor rod, the length is 3m, the distance is 1.5 multiplied by 1.5m, and the bar planting rings are arranged in a plum blossom shape.
The step S200 takes the following approach,
s201, constructing a grout stopping wall; before grouting construction, a closed working surface of the grout stop wall needs to be constructed to prevent grout leakage and grout leakage in the grouting process, the construction thickness of the grout stop wall is at least 2m, C30 molded concrete is adopted for construction, rework and construction period delay caused by cracking of the grout stop wall in the high-pressure grouting process are avoided. Double-layer phi 8 steel bar net sheets are continuously arranged in the grout stop wall, the interlayer spacing is 1m, and the overall stability of concrete is improved. Concrete pouring needs to be vibrated compactly to prevent slurry leakage. The water diversion orifice pipe is connected to the outside of the grout stopping wall.
The grout stopping wall is poured 7 times, the grout stopping wall is constructed according to steps and is convenient to construct, the height of each pouring is 1.2-2 m, each layer of grout stopping wall is provided with phi 22 connecting ribs, the length of each layer of grout stopping wall is 2m, the grout stopping wall is arranged in a plum blossom shape of 1.5 multiplied by 1.5m, bamboo plywood and wood boards are used as templates for pouring the grout stopping wall, the templates are oppositely pulled and reinforced by phi 42 steel pipes and reinforcing steel bars, and the grout stopping wall is provided with cross braces and throwing braces to prevent the templates from deforming due to overlarge lateral pressure during pouring.
The pouring work needs to be carried out continuously and quickly for layering and tamping, the layering thickness is 40cm, when the grout stopping wall is poured to the vault of 50cm, grouting pipes are reserved at the vault and the arch shoulder part every 1.5m, the poor concrete pouring effect of the vault part is prevented, and grouting and leaking stoppage can be carried out. Pouring is difficult to carry out, capping can be carried out by adopting sprayed concrete, a layer of 5-10 cm mortar is sprayed on the surface of the surrounding rock by the sprayed concrete, and then the sprayed concrete is sprayed outwards from the side of the wall. When the grout stopping wall is poured, attention should be paid to concrete compactness. After the construction of the grout stopping wall is finished, curing and consolidation are needed, and double-liquid grouting is added at the bottom of the grout stopping wall.
A phi 42 grouting advanced small guide pipe is arranged in surrounding rock in front of the tunnel face, the length is 3m, the distance is 2 multiplied by 2m, and the pipe is arranged in a plum blossom shape.
S202, field hardening treatment; and reserving an operation platform behind the grout stopping wall, wherein the operation platform is backfilled by using the hole slag, is distributed in the full width, is about 12.5 meters wide, about 3.7 meters high and about 10 meters long, is connected with the bottom of the tunnel according to the gradient of 1:3, and reserves a clearance of 4.7 meters. And after leveling the backfill hole slag, pouring a hardened layer with the thickness of 15cm by using C20 concrete as a drilling machine construction platform.
S203, grouting and reinforcing the grout stopping rock; grouting and reinforcing an arch part at the beginning, considering that a cavity condition possibly exists after a first support back, during grouting, a slurry flowing channel exists, grouting construction cannot be smoothly carried out, implementing 4-ring advanced grouting small pipes on the arch part at the back of a grout stop wall, wherein the small pipes are 2m long and 1.5m apart, arranged in a plum blossom shape, and grouting to block the cavity possibly existing after the first support back; grouting and reinforcing the periphery of the grout stopping wall, after the grout stopping wall is sealed, adopting an air gun to drill holes in the arch part of the grout stopping wall within 60 degrees, installing phi 42 seamless rigid pipes, penetrating the grout stopping wall through steel pipes to penetrate the surrounding rock of the tunnel face by 1.8m, and grouting and anchoring.
S204-slurry stopping wall pressure test. And (4) water shutoff inspection: and after the reinforcement is completed for half an hour, closing water to check whether the grout stopping wall has leakage or not, and checking whether the orifice pipe has a loosening phenomenon or not, if the grout stopping wall has no leakage, performing curtain grouting, and if the grout stopping wall still has water seepage, re-reinforcing the grout stopping wall. When water is shut off, whether the grout stopping wall has water seepage or not is observed, if the grout stopping wall has abnormity, the test is immediately stopped, and the test is carried out after the reason is found out and the grout stopping wall is treated. The water shut-off should be performed slowly. And after the sealing and reinforcing of the grout stopping wall are finished, closing the gate valves of the water outlets in sequence and measuring the water pressure.
Step S500 is that the method is adopted, drilling is carried out within the thickness range of the grout stop wall according to the drilling distance, after the drilling is finished, an orifice pipe is installed, the orifice pipe is machined by seamless steel pipes with the diameter of phi 108mm and the diameter of delta =6mm, the pipe length is 2.5m, 3 protective hoops are welded on the outer side of the orifice pipe by wire rods with the diameter of phi 6mm, hemp threads with the length of 50-80 cm are wound on the outer wall of the orifice pipe to form a spindle shape, the spindle shape is installed by a drilling machine in an impacting mode, the spindle shape is exposed for 20cm, the spindle shape is anchored by an anchoring agent to ensure that the orifice pipe is firmly installed and does not leak grout, the next step of drilling is carried out after the orifice pipe is solidified for more than 12 hours. And after the orifice pipe is installed, drilling is carried out, and the water inflow is measured so as to guide grouting construction.
Step S600, adopting the following method, after the grout stopping wall and the drilling machine platform are finished, carrying out full-section curtain grouting through the upper step, forming a stable consolidation body with a certain thickness and certain water pressure resistance outside the tunnel excavation contour line, improving the bearing capacity of the surrounding rock of the arch part, and ensuring tunnel excavation and structure safety. And (4) implementing forward segmented drilling grouting according to the grouting sequence and depth of the design drawing. The length of the longitudinal grouting section is related to factors such as geological conditions, drilling machine capacity, grouting process and the like, the length of 40m and the length of a grouting section are processed in each cycle according to relevant literature research and by combining the site construction condition of the Hongtian extra-long tunnel, 5m is reserved after grouting is finished without excavation, and whether grouting reinforcement is continued or not is determined according to the next cycle advanced geological forecast conclusion.
In step S600, the following method is adopted for the forward sectional drilling grouting:
s601-drilling segment length principle: the section length is 10m when the water amount is 0-10 m3/h, the section length is 5m when the water amount is 10-30 m3/h, and the drilling is stopped immediately to implement grouting when the water amount is more than 30m 3/h.
S602-grouting hole position arrangement: the grouting holes are radially arranged according to an umbrella shape, the drilling holes are arranged into one circle or a plurality of circles, the inner circle and the outer circle are arranged according to a plum blossom shape, and the long holes and the short holes are combined.
S603, drilling according to the drilling section length principle, when the water yield in the hole does not meet the drilling requirement, grouting is carried out, after the slurry is solidified, drilling operation is carried out, and the steps are circulated until the hole is drilled to the designed hole depth position; and when the drilling hole section needs grouting, immediately performing drilling hole flushing work, wherein the purpose of drilling hole flushing is to clear away residual rock powder in the drilling hole, clay impurities filled in rock cracks and the like. The punching mode adopts a water discharging mode of pressure sudden rising and sudden reduction, and the standard of the flushing end is as follows: the water in the water outlet pipe is cleaned and then continues for 10min, the total flushing time is not less than 30min, and the flushing time is increased for special cases.
S604, pulping and grouting, wherein a blade type stirrer is selected as pulping equipment, a vertical motor and a cycloidal pin wheel type speed reducer are adopted, a bracket is arranged on a pulp storage barrel in an inverted mode, and power is directly transmitted to a stirring shaft through a coupling. In order to facilitate slurry suction, more than two slurry taking ports are arranged on the outer side of the slurry storage barrel so as to ensure the supply of slurry during large-flow grouting. Mixing the slurry according to the selected proportioning parameters of the slurry, filtering the slurry by using a 1 multiplied by 1mm mesh screen after the slurry is mixed, and placing the slurry into a blade vertical stirrer for secondary stirring, wherein the stirring time is not less than 30s, so that the slurry is ensured to be uniform; the outer ring is poured firstly, the inner ring is poured secondly, the slurry is diluted firstly and then compacted from top to bottom at intervals, the slurry is properly adjusted according to the conditions of drilling and surrounding rocks, when the slurry inlet amount is large or the slurry is mixed, the pressure is not increased for a long time, the slurry is poured by taking the measure of gradually thickening the slurry, the gel time is shortened, and the slurry is poured with small pump amount and low pressure so that the slurry has relative residence time in the rock stratum fracture for gelation.
And S605-grouting, wherein the pressure gradually rises, the flow gradually falls, grouting is continued for more than 10min when the designed final pressure is reached, and grouting can be finished when the grouting speed is less than 30L/min.
Step S700, selecting a grouting position with a weak link in a grouting range to arrange an inspection hole according to a grouting condition, performing drilling inspection on a grouting effect, and measuring water inflow; and if the water inflow of each inspection hole per linear meter of each hole is more than 0.2L/min or the water inflow of a local hole is more than 10L/min, additionally drilling and grouting, and grouting again until the design requirement is met.
Compared with the prior art, the invention has the following beneficial effects:
1. the advanced geological prediction means is fully utilized to guide the selection of curtain grouting construction parameters, and the tunnel tunneling construction safety and the stability of the secondary lining structure are ensured.
2. The waterproof board is adopted to collect the water scattered on the tunnel face, so that the construction of the concrete of the grout stopping wall is facilitated, the construction parameters such as the thickness of the grout stopping wall and reinforcing measures are reasonably optimized, the smooth proceeding of the subsequent grouting process is ensured under the condition of achieving the purpose of completely blocking water in the early stage, and the construction cost is saved.
3. Construction parameters such as the number of grouting holes, the range of the reinforcing ring, the hole brushing rate and the like are reasonably optimized, the purposes of blocking water and reinforcing surrounding rocks are achieved, and the construction cost is saved.
4. A controlled area grouting technology: the setting time of the double-liquid slurry is mastered by adjusting the mixing proportion, a drain hole is drilled at a position far away from the grouting hole, so that the double-liquid slurry is set before being discharged from the drain hole when the grouting hole is grouted, and the aim of filling the crack with the slurry is fulfilled.
5. The single-double liquid grouting replacement technology comprises the following steps: when the water pressure is large and the crack develops, and the single grout can not be timely condensed during the injection, the cement-water-glass double-grout can be adopted, and the single-grout is switched after the grouting pressure rises. When the slurry is mixed and leaked during grouting, the cement-water glass double-liquid slurry grouting is replaced in time.
6. Protecting the ecological environment and water system of the mountain in the tunnel site area to the maximum extent.
Drawings
FIG. 1 is a schematic flow chart of the present invention.
Detailed Description
A full-section advanced curtain grouting construction method for a water-rich broken geological zone tunnel comprises the following steps of S100-construction preparation; s200, constructing a grout stopping wall; s300, measuring and paying off, marking hole positions, releasing the hole positions on a working surface according to the hole positions and the drilling parameters of a design drawing, and calibrating by using paint; s400, drilling holes, adjusting the elevation angle and the horizontal angle of the drill rod, moving the drilling machine, and aligning the drill bit to the marked hole position. Placing a prism at the tail end of the drill rod, and checking and adjusting the posture of the drill rod by using a total station; s500, mounting an orifice pipe; s600, advancing type sectional grouting; s700, detecting the grouting effect by drilling.
Step S100 takes the following approach:
s101, overhauling and maintaining the drilling machine and the grouting pump, processing a hole pipe, preparing a grouting material and carrying out a slurry test.
S102, water is led through a drain hole; before the grout stopping wall is constructed, cleaning a base to a base rock surface, flushing water at a plurality of positions in the range of a tunnel face due to the development of joint cracks of surrounding rocks, covering and sealing the tunnel face by using a waterproof plate, and collecting and dispersing water; after the pre-reinforcing measures are finished, C30 concrete is adopted to pour a 1m high concrete water retaining bank with the thickness of 40cm, and a water drainage steel pipe is embedded at the bottom of the water retaining bank to conduct water to a ditch outside the construction platform; considering that the water pressure of a water burst point on the tunnel face is large, a high-pressure gate valve, a matched flange plate and a matched high-pressure steel gasket are adopted at a pipeline joint; preparing a plurality of phi 108 steel pipes for guiding and draining the scattered water in the construction process of the grout stop wall, collecting the scattered water and then intensively draining the scattered water to ditches at two sides outside the grout stop wall.
S103, pre-reinforcing measures; in order to ensure the stability of the grout stop wall, steel bars are planted in the circumferential range of the grout stop wall, and a small advanced grouting guide pipe is implemented on the tunnel face so as to increase the anchoring force between the grout stop wall and surrounding rocks on the tunnel face; before the grout stopping wall is constructed, an excavator is adopted to cooperate with manual work to firstly clean the substrate to the rock surface, and the steel bars are planted at the bottom of the grout stopping wall and in the whole circle of primary support range. The number of the bar planting rings is two, the bar planting adopts a phi 22 cartridge anchor rod, the length is 3m, the distance is 1.5 multiplied by 1.5m, and the bar planting rings are arranged in a plum blossom shape.
The step S200 takes the following approach,
s201, constructing a grout stopping wall; before grouting construction, a closed working surface of the grout stop wall needs to be constructed to prevent grout leakage and grout leakage in the grouting process, the construction thickness of the grout stop wall is at least 2m, C30 molded concrete is adopted for construction, rework and construction period delay caused by cracking of the grout stop wall in the high-pressure grouting process are avoided. Double-layer phi 8 steel bar net sheets are continuously arranged in the grout stop wall, the interlayer spacing is 1m, and the overall stability of concrete is improved. Concrete pouring needs to be vibrated compactly to prevent slurry leakage. The water diversion orifice pipe is connected to the outside of the grout stopping wall.
The grout stopping wall is poured 7 times, the grout stopping wall is constructed according to steps and is convenient to construct, the height of each pouring is 1.2-2 m, each layer of grout stopping wall is provided with phi 22 connecting ribs, the length of each layer of grout stopping wall is 2m, the grout stopping wall is arranged in a plum blossom shape of 1.5 multiplied by 1.5m, bamboo plywood and wood boards are used as templates for pouring the grout stopping wall, the templates are oppositely pulled and reinforced by phi 42 steel pipes and reinforcing steel bars, and the grout stopping wall is provided with cross braces and throwing braces to prevent the templates from deforming due to overlarge lateral pressure during pouring.
The pouring work needs to be carried out continuously and quickly for layering and tamping, the layering thickness is 40cm, when the grout stopping wall is poured to the vault of 50cm, grouting pipes are reserved at the vault and the arch shoulder part every 1.5m, the poor concrete pouring effect of the vault part is prevented, and grouting and leaking stoppage can be carried out. Pouring is difficult to carry out, capping can be carried out by adopting sprayed concrete, a layer of 5-10 cm mortar is sprayed on the surface of the surrounding rock by the sprayed concrete, and then the sprayed concrete is sprayed outwards from the side of the wall. When the grout stopping wall is poured, attention should be paid to concrete compactness. After the construction of the grout stopping wall is finished, curing and consolidation are needed, and double-liquid grouting is added at the bottom of the grout stopping wall.
A phi 42 grouting advanced small guide pipe is arranged in surrounding rock in front of the tunnel face, the length is 3m, the distance is 2 multiplied by 2m, and the pipe is arranged in a plum blossom shape.
S202, field hardening treatment; and reserving an operation platform behind the grout stopping wall, wherein the operation platform is backfilled by using the hole slag, is distributed in the full width, is about 12.5 meters wide, about 3.7 meters high and about 10 meters long, is connected with the bottom of the tunnel according to the gradient of 1:3, and reserves a clearance of 4.7 meters. And after leveling the backfill hole slag, pouring a hardened layer with the thickness of 15cm by using C20 concrete as a drilling machine construction platform.
S203, grouting and reinforcing the grout stopping rock; grouting and reinforcing an arch part at the beginning, considering that a cavity condition possibly exists after a first support back, during grouting, a slurry flowing channel exists, grouting construction cannot be smoothly carried out, implementing 4-ring advanced grouting small pipes on the arch part at the back of a grout stop wall, wherein the small pipes are 2m long and 1.5m apart, arranged in a plum blossom shape, and grouting to block the cavity possibly existing after the first support back; grouting and reinforcing the periphery of the grout stopping wall, after the grout stopping wall is sealed, adopting an air gun to drill holes in the arch part of the grout stopping wall within 60 degrees, installing phi 42 seamless rigid pipes, penetrating the grout stopping wall through steel pipes to penetrate the surrounding rock of the tunnel face by 1.8m, and grouting and anchoring.
S204-slurry stopping wall pressure test. And (4) water shutoff inspection: and after the reinforcement is completed for half an hour, closing water to check whether the grout stopping wall has leakage or not, and checking whether the orifice pipe has a loosening phenomenon or not, if the grout stopping wall has no leakage, performing curtain grouting, and if the grout stopping wall still has water seepage, re-reinforcing the grout stopping wall. When water is shut off, whether the grout stopping wall has water seepage or not is observed, if the grout stopping wall has abnormity, the test is immediately stopped, and the test is carried out after the reason is found out and the grout stopping wall is treated. The water shut-off should be performed slowly. And after the sealing and reinforcing of the grout stopping wall are finished, closing the gate valves of the water outlets in sequence and measuring the water pressure.
Step S500 is that the method is adopted, drilling is carried out within the thickness range of the grout stop wall according to the drilling distance, after the drilling is finished, an orifice pipe is installed, the orifice pipe is machined by seamless steel pipes with the diameter of phi 108mm and the diameter of delta =6mm, the pipe length is 2.5m, 3 protective hoops are welded on the outer side of the orifice pipe by wire rods with the diameter of phi 6mm, hemp threads with the length of 50-80 cm are wound on the outer wall of the orifice pipe to form a spindle shape, the spindle shape is installed by a drilling machine in an impacting mode, the spindle shape is exposed for 20cm, the spindle shape is anchored by an anchoring agent to ensure that the orifice pipe is firmly installed and does not leak grout, the next step of drilling is carried out after the orifice pipe is solidified for more than 12 hours. And after the orifice pipe is installed, drilling is carried out, and the water inflow is measured so as to guide grouting construction.
Step S600, adopting the following method, after the grout stopping wall and the drilling machine platform are finished, carrying out full-section curtain grouting through the upper step, forming a stable consolidation body with a certain thickness and certain water pressure resistance outside the tunnel excavation contour line, improving the bearing capacity of the surrounding rock of the arch part, and ensuring tunnel excavation and structure safety. And (4) implementing forward segmented drilling grouting according to the grouting sequence and depth of the design drawing. The length of the longitudinal grouting section is related to factors such as geological conditions, drilling machine capacity, grouting process and the like, the length of 40m and the length of a grouting section are processed in each cycle according to relevant literature research and by combining the site construction condition of the Hongtian extra-long tunnel, 5m is reserved after grouting is finished without excavation, and whether grouting reinforcement is continued or not is determined according to the next cycle advanced geological forecast conclusion.
In step S600, the following method is adopted for the forward sectional drilling grouting:
s601-drilling segment length principle: the section length is 10m when the water amount is 0-10 m3/h, the section length is 5m when the water amount is 10-30 m3/h, and the drilling is stopped immediately to implement grouting when the water amount is more than 30m 3/h.
S602-grouting hole position arrangement: the grouting holes are radially arranged according to an umbrella shape, the drilling holes are arranged into one circle or a plurality of circles, the inner circle and the outer circle are arranged according to a plum blossom shape, and the long holes and the short holes are combined.
S603, drilling according to the drilling section length principle, when the water yield in the hole does not meet the drilling requirement, grouting is carried out, after the slurry is solidified, drilling operation is carried out, and the steps are circulated until the hole is drilled to the designed hole depth position; and when the drilling hole section needs grouting, immediately performing drilling hole flushing work, wherein the purpose of drilling hole flushing is to clear away residual rock powder in the drilling hole, clay impurities filled in rock cracks and the like. The punching mode adopts a water discharging mode of pressure sudden rising and sudden reduction, and the standard of the flushing end is as follows: the water in the water outlet pipe is cleaned and then continues for 10min, the total flushing time is not less than 30min, and the flushing time is increased for special cases.
S604, pulping and grouting, wherein a blade type stirrer is selected as pulping equipment, a vertical motor and a cycloidal pin wheel type speed reducer are adopted, a bracket is arranged on a pulp storage barrel in an inverted mode, and power is directly transmitted to a stirring shaft through a coupling. In order to facilitate slurry suction, more than two slurry taking ports are arranged on the outer side of the slurry storage barrel so as to ensure the supply of slurry during large-flow grouting. Mixing the slurry according to the selected proportioning parameters of the slurry, filtering the slurry by using a 1 multiplied by 1mm mesh screen after the slurry is mixed, and placing the slurry into a blade vertical stirrer for secondary stirring, wherein the stirring time is not less than 30s, so that the slurry is ensured to be uniform; the outer ring is poured firstly, the inner ring is poured secondly, the slurry is diluted firstly and then compacted from top to bottom at intervals, the slurry is properly adjusted according to the conditions of drilling and surrounding rocks, when the slurry inlet amount is large or the slurry is mixed, the pressure is not increased for a long time, the slurry is poured by taking the measure of gradually thickening the slurry, the gel time is shortened, and the slurry is poured with small pump amount and low pressure so that the slurry has relative residence time in the rock stratum fracture for gelation.
The grouting material mainly adopts common cement single-liquid slurry and HPC (stone rate improvement), and adopts common cement-water-glass double-liquid slurry as auxiliary material; the cement is No. 425 common portland cement, and the fineness of the cement requires that the screen allowance of the cement passing through an 80-micron square-hole screen is not more than 5%. The concentration of the water glass is 30-45 Baume degrees. The water-cement ratio of the ordinary portland cement single-liquid slurry is 0.8-1: 1, the mixing amount of HPC is 15-20% of the cement consumption. The water slurry and glass double-slurry ratio is as follows: w: C = 0.8-1: 1, and C: S =1: 1. Before grouting, a field grouting test is carried out, and actual grouting parameters are determined according to the surrounding rock condition. When the water pressure is large and the crack develops, and the single-liquid slurry can not be condensed in time when being injected, the cement-water-glass double-liquid slurry can be adopted, and the single-liquid slurry is switched after the water pressure in the hole is small.
Grouting sequence: through the reasonable selection slip casting order, can not only improve slip casting efficiency, can also guarantee the slip casting effect. Optimally designing the grouting sequence by combining the divergence-constraint grouting principle, and providing: and (4) performing hole jumping grouting construction operation from outside to inside, from top to bottom and at intervals. The grouting sequence is A → B → C → D → E.
Grouting parameters: the grouting reinforcement range is 6-8 m outside the contour line of the tunnel, and the diffusion radius of the grout is not less than 2.5 m.
The initial grouting pressure is not less than 2MPa, the final pressure is not less than 3 times of the water pressure in the hole and not less than 2MPa, and the maximum grouting pressure is not less than 5 MPa.
And S605-grouting, wherein the pressure gradually rises, the flow gradually falls, grouting is continued for more than 10min when the designed final pressure is reached, and grouting can be finished when the grouting speed is less than 30L/min.
Step S700, selecting a grouting position with a weak link in a grouting range to arrange an inspection hole according to a grouting condition, performing drilling inspection on a grouting effect, and measuring water inflow; and if the water inflow of each inspection hole per linear meter of each hole is more than 0.2L/min or the water inflow of a local hole is more than 10L/min, additionally drilling and grouting, and grouting again until the design requirement is met.
Example (b): the tunnel design surrounding rock is medium-slightly weathered granite, the geological conditions are extremely complex, cracks develop, and the tunnel site passes through 16 fracture structures and a plurality of low-resistance abnormal zones. 1262m from the tunnel entrance to K94+480 section is a down slope with a gradient of-0.4%, and is a reverse slope along the tunneling direction by taking K94+480 as a boundary, namely a downhill section with a gradient of 2%, the construction length of the reverse slope reaches 2.0Km, and the right water burst face is positioned at the reverse slope section of the tunnel, so that water seepage and water burst in the tunnel can be collected along the slope to the face under the action of gravity, therefore, the accumulated water needs to be pumped and drained in time to prevent the water accumulation on the construction face from being too deep, which affects the stability of tunnel surrounding rocks and endangers the safety of mechanical equipment and constructors in tunnel construction. Tunneling the tunnel face of the left tunnel line to ZK94+238, exposing a vertical opening crack at the arch shoulder position of the right side of the line, wherein the width of the crack is about 3-20 cm, after long-time water drainage and pressure reduction, the water inflow is not obviously reduced, the daily water inflow is about 15000m3/d, and the actually measured water pressure of the tunnel face is 2.1 MPa; tunneling the tunnel face of the right tunnel line to a mileage K94+076, and spraying water in the drilled hole in the process of constructing the advanced small guide pipe, wherein the spraying distance is 2-3 m, the daily water inflow is about 20000m3/d, and the actual water pressure of the tunnel face is 3.6 MPa.
After the construction method is adopted for construction of the left and right lines of the tunnel, blasting excavation is carried out on the surrounding rock of the grouting section after curtain grouting is finished, the crack zone grout is fully filled after the surrounding rock excavation, the local grout filling width reaches 19cm, and the sprayed concrete surface is only locally wet after primary support. Because the whole crack of the tunnel has stronger connectivity, after the front face is grouted and sealed, part of crack water is discharged from the crack near the back of the face (in the direction of the opening). Through the contrast of tunnel slip casting section and the surrounding rock infiltration condition of the section that does not slip casting, the technical measure is reasonable effective, and the problem of gushing water in the tunnel can effectually be solved in advance curtain slip casting, and mountain surface ecological environment has obtained effective protection to guarantee engineering quality and construction safety.

Claims (7)

1. A full-section advanced curtain grouting construction method for a tunnel in a water-rich broken geological zone is characterized by comprising the following steps of: comprises the following steps of (a) carrying out,
s100, preparing for construction;
s200, constructing a grout stopping wall;
s300, measuring paying off and marking hole positions;
s400, drilling holes;
s500, mounting an orifice pipe;
s600, advancing type sectional grouting;
s700, detecting the grouting effect by drilling.
2. The construction method of the full-section advanced curtain grouting of the water-rich fractured geological zone tunnel according to claim 1, characterized by comprising the following steps: the step S100 described takes the following approach,
s101, overhauling and maintaining a drilling machine and a grouting pump, processing a hole pipe, preparing a grouting material and carrying out a slurry test;
s102, water is led through a drain hole; before the grout stopping wall is constructed, cleaning a base to a base rock surface, flushing water at a plurality of positions in the range of a tunnel face due to the development of joint cracks of surrounding rocks, covering and sealing the tunnel face by using a waterproof plate, and collecting and dispersing water; after the pre-reinforcing measures are finished, adopting a concrete pouring concrete water blocking bank, and embedding a water drainage steel pipe at the bottom of the water blocking bank to conduct water to a ditch outside the construction platform; preparing a plurality of steel pipes for guiding and discharging scattered water in the construction process of the grout stopping wall, collecting the scattered water and then intensively discharging the scattered water to ditches at two sides outside the grout stopping wall;
s103, pre-reinforcing measures; planting ribs in the circumferential range of the grout stop wall, and grouting a small advanced guide pipe on the tunnel face to increase the anchoring force of the grout stop wall and surrounding rocks on the tunnel face; before the grout stopping wall is constructed, the base is cleaned to the rock surface, and the reinforcing bars are planted at the bottom of the grout stopping wall and in the whole circle of the primary support range.
3. The construction method of the full-section advanced curtain grouting of the water-rich fractured geological zone tunnel according to claim 2, characterized by comprising the following steps: the step S200 described takes the following approach,
s201, constructing a grout stopping wall; before grouting construction, a closed working surface of a grout stopping wall needs to be constructed, the construction thickness of the grout stopping wall is at least 2m, C30 molded concrete is adopted for construction, double-layer reinforcing steel bar meshes are continuously arranged in the grout stopping wall, and a water diversion orifice pipe is connected to the outside of the grout stopping wall;
pouring the grout stopping wall 7 times, constructing according to steps, wherein the height of each pouring is 1.2-2 m, each layer is provided with a connecting rib, the length of each connecting rib is 2m, and the connecting ribs are arranged in a plum blossom shape of 1.5 multiplied by 1.5m, and pouring the grout stopping wall;
the pouring work needs to be carried out continuously and quickly for layering and drum tamping, when the grout stopping wall is poured to the vault of 50cm, grouting pipes are reserved at the vault and the arch shoulder part every 1.5m, after the construction of the grout stopping wall is finished, maintenance and consolidation are needed, and double-liquid grouting is added at the bottom of the grout stopping wall;
a small grouting advance conduit is arranged in the surrounding rock in front of the tunnel face, the length is 3m, the distance is 2 multiplied by 2m, and the small grouting advance conduit is arranged in a plum blossom shape;
s202, field hardening treatment; reserving an operation platform behind the grout stop wall, backfilling the operation platform by using hole slag, connecting the operation platform with the tunnel bottom according to the gradient of 1:3, and leveling the backfilled hole slag, and then, adopting a concrete-poured thick hardened layer as a drilling machine construction platform;
s203, grouting and reinforcing the grout stopping rock; grouting and reinforcing an arch part primary support, implementing 4-ring advanced grouting small pipes on the arch part primary support behind a grout stop wall, and grouting to block cavities possibly existing behind the primary support back; grouting and reinforcing the periphery of the grout stopping wall, after the grout stopping wall is sealed, adopting an air gun to drill holes in the arch part of the grout stopping wall within 60 degrees, installing seamless rigid pipes, penetrating the grout stopping wall through steel pipes to penetrate the surrounding rock of the tunnel face by 1.8m, and grouting and anchoring;
s204-slurry stopping wall pressure test.
4. The construction method of the full-face advanced curtain grouting of the water-rich fractured geological zone tunnel according to claim 3, characterized by comprising the following steps: and S500, drilling holes in the thickness range of the grout stop wall according to the drilling hole intervals, mounting the hole pipes after the drilling is finished, anchoring by using an anchoring agent to ensure that the hole pipes are firmly installed and do not leak grout, drilling the holes after the hole pipes are solidified for more than 12 hours, and measuring the water inflow amount to guide grouting construction.
5. The construction method of the full-face advanced curtain grouting of the water-rich fractured geological zone tunnel according to claim 4, characterized by comprising the following steps: and S600, after the grout stopping wall and the drilling machine platform are finished, full-face curtain grouting is carried out through the upper step, a stable consolidation body is formed outside the tunnel excavation contour line, advancing type subsection drilling grouting is carried out, and whether grouting reinforcement is carried out continuously is determined according to the next cycle advanced geological forecast conclusion.
6. The construction method of the full-face advanced curtain grouting of the water-rich fractured geological zone tunnel according to claim 5, characterized by comprising the following steps: in the step S600, the following method is adopted for the forward subsection drilling grouting,
s601-drilling segment length principle: the section length is 10m when the water amount is 0-10 m3/h, the section length is 5m when the water amount is 10-30 m3/h, and the drilling is immediately stopped to implement grouting when the water amount is more than 30m 3/h;
s602-grouting hole position arrangement: the grouting holes are radially arranged according to an umbrella shape, the drilling holes are arranged into one circle or a plurality of circles, the inner circle and the outer circle are arranged according to a plum blossom shape, and the long holes and the short holes are combined;
s603, drilling according to the drilling section length principle, when the water yield in the hole does not meet the drilling requirement, grouting is carried out, after the slurry is solidified, drilling operation is carried out, and the steps are circulated until the hole is drilled to the designed hole depth position; when the drilling hole section needs grouting, immediately performing drilling hole flushing work, wherein the purpose of drilling hole flushing is to clear away residual rock powder in a drilling hole, clay impurities filled in a rock crack and the like;
the punching mode adopts a water discharging mode of pressure sudden rising and sudden reduction, and the standard of the flushing end is as follows: cleaning water in the water outlet pipe, and continuing for 10min, wherein the total flushing time is not less than 30 min;
s604, pulping and grouting, wherein an outer ring is firstly injected, an inner ring is then injected, the inner ring is firstly diluted and then compacted, the grouting is performed at intervals from top to bottom, when the slurry inlet amount is large or slurry is mixed, the pressure is not increased for a long time, the grouting is performed by adopting the measure of gradually thickening the slurry, the gelling time is shortened, and the grouting is performed at a low pump amount and a low pressure so that the slurry has relative residence time in the cracks of the rock stratum so as to facilitate gelling;
and S605-grouting, wherein the pressure gradually rises, the flow gradually falls, grouting is continued for more than 10min when the designed final pressure is reached, and grouting can be finished when the grouting speed is less than 30L/min.
7. The construction method of the full-face advanced curtain grouting of the water-rich fractured geological zone tunnel according to claim 6, characterized by comprising the following steps: the step S700 is that a method is adopted, according to the grouting condition, a grouting position with a weak link in the grouting range is selected to arrange an inspection hole, the grouting effect is subjected to drilling inspection, and the water inflow amount is measured; and if the water inflow of each inspection hole per linear meter of each hole is more than 0.2L/min or the water inflow of a local hole is more than 10L/min, additionally drilling and grouting, and grouting again until the design requirement is met.
CN202011393988.4A 2020-12-03 2020-12-03 Full-section advanced curtain grouting construction method for water-rich broken geological zone tunnel Pending CN112412496A (en)

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CN114109442B (en) * 2021-10-18 2024-02-09 中铁十局集团第一工程有限公司 Tunnel karst crushing belt sliding collapse half-section curtain progressive grouting reinforcement treatment method
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