CN101761346A - Method for constructing metamorphic rock confined water tunnel - Google Patents

Abstract

The invention relates to the field of tunnel construction, in particular to a method for constructing a metamorphic rock confined water tunnel, which solves the problems of the current method that geological disaster is easily initiated, the digging outline is difficult to control, timbering at initial stage is easy to transform and craze and the collapse is easy to occur. The method comprises the steps of: preliminarily forecasting surrounding rock level and underground water developing condition, accurately forecasting the geologic condition and the underground water developing condition by an advanced prospect hole, draining and decreasing water pressure by an advanced borehole, fixing the surrounding rock and plugging water by grouting via an advanced ductile, choosing a digging manner of tunnel trunk, determining the timbering form at initial stage, constructing a radial ductile, digging an inverted arch, pouring inverted arch concrete, and constructing a secondary lining. The construction method of the invention can efficiently control the digging outline, decrease the collapse frequency and the scale, efficiently control the transformation and cracking of the timbering at initial stage and can almost avoid the tunnel collapse by secondarily exchanging arch. The cost is decreased and the construction quality and the construction safety are efficiently promoted so as to bring excellent social benefit.

Description

A kind of job practices of metamorphic rock confined water tunnel

Technical field

The present invention relates to the tunnel construction field, be specially a kind of job practices of metamorphic rock confined water tunnel.

Background technology

Metamorphic rock confined water tunnel country rock characteristics are that joint fissure is grown, joint plane is intensive, smooth, rock is bulk or chunky shape crush texture, rock monomer intensity height, and be mingled with the weak charges of thin layer, the country rock globality is poor, and a little less than the self-stable ability, the multilayer artesian water causes barrel excavation back not have water water outlet in a few days at that time and became big gradually with regard to water outlet and after becoming big or excavation gradually.Not water outlet, the supporting and protection structure stability and safety, in case water outlet, the filler in the crack will soften with the current mistake, makes the globality and the bad stability of country rock, and support system pressure is increased, and causes water outlet position and near supporting cracking thereof, steel frame deformation, fractures.

At present, constructing tunnel is carried out in rock artesian water location on the turn, because not dark to metamorphic rock rock mass characteristics understanding, damaging effect to artesian water is underestimated, and does not have rational specific aim constructure scheme when construction, still constructs by traditional constructure scheme, cause geological disasters such as gushing water, prominent mud, landslide easily, the excavation profile is difficult to control, and it is serious to backbreak, and falls piece and caves in and happen occasionally, easy early period of origination supporting strain cracking, steelframe twists, fractures, the preliminary bracing fouling of clearance gauge, even landslide appears.Task difficulty is big under this external artesian water condition, sprayed mortar just has little time to solidify and is broken up, welding fluid has little time to weld to glue and just is condensed during weld job, the big gun hole has little time to stop up powder stick and just is rushed out when boring quick-fried operation, slurries have little time just to solidify and are flushed away during slip casting, construction quality is difficult to guarantee, the stressed complexity of the support system cracking that very easily deforms.It is big that waterproofing course is not only laid the welding difficulty, and suffer very easily that artesian water destroys and cause secondary lining percolating water.

Summary of the invention

The present invention adopts the conventional tunnel job practices in order to solve existing metamorphic rock confined water tunnel, exist and easily to cause geological disaster, excavation profile and be difficult to problems such as control, preliminary bracing strain cracking and easily landslide, construction operation difficulty are big, a kind of job practices of metamorphic rock confined water tunnel is provided.

The present invention adopts following technical scheme to realize: a kind of job practices of metamorphic rock confined water tunnel may further comprise the steps: A tentative prediction country rock rank and underground water developmental state; Inspecting hole accurately forecasts geological condition and underground water developmental state before the B ultrasonic: according to the tentative prediction conclusion, survey at having artesian water or Fu Shui location and complicated geology location to take horizontal drill to carry out advance borehole, accurately judge country rock lithology, architectural feature by the core sampling, accurately judge underground water developmental state and pressure condition thereof by the inspecting hole water yield, leading inspecting hole adopts RPD-150C rig Φ 110mm drill bit to drill, every 50m probing is once drilled 60m at every turn; C advance borehole sluicing step-down: rich water and artesian water location are taked advance borehole sluicing step-down according to the advance borehole result of detection, leading spilled water hole adopts XY-2PC rig Φ 91mm drill bit to hole, every 25m holes once, and drilling depth 30m holes 3～7 at every turn; Leading grouting with small pipe concretion marginsing rock of D and water blockoff: in 120 °～180 ° scopes in barrel arch, perform leading ductule along the tunnel excavation outline line, cementing-water glass biliquid slurry, the cement-sodium silicate double liquid parameter: cement grout water ash weight ratio is 1: 1, mortar water glass volume ratio is 1: 0.8, modulus of water glass m=2.4～3.4, concentration Be=30～40, grouting pressure is controlled at 0.5～1.0MPa, and grout spreading range is not less than 30cm; E selects the barrel digging mode and determines the preliminary bracing form: through advance borehole sluicing and ductule pre-grouting, metamorphic rock confined water tunnel is by three benching tunnelling methods or go up arc guide and reserve core soil three benching tunnelling methods and construct, and applies the preliminary bracing of corresponding form simultaneously; E performs radially ductule: perform radially ductule after supporting in the early stage performs and finishes; G excavation inverted arch is also built the inverted arch concrete: after the barrel excavation supporting is finished, carry out inverted arch E construction immediately, the inverted arch construction is once excavated and concreting length must not surpass 6m; H performs secondary lining: before inverted arch construction the finishing lining cutting, by the cement-sodium silicate double liquid described in the ductule perfusion step D.Three benching tunnelling methods that adopted during described barrel excavation or go up arc guide and reserve core soil three benching tunnelling methods and be well known to those of ordinary skill in the art all have ripe job specfication in the constructing tunnel field, preliminary bracing should strictly apply by design or code requirement.

In construction, metamorphic rock confined water tunnel is difficult to control excavation profile, very easily fall piece, cave in, metamorphic rock confined water tunnel of the present invention adopts three step microseismic activity controlled blasting methods excavation, when boring quick-fried design, all periphery holes of arranging along the excavation outline line adopt the detonating fuse series connection, and periphery hole adopts spaced loading form (i.e. blashole charge, two boreholes that are adjacent are only put detonating fuse); During last arc guide explosion, according to last arc guide profiled outline arranged in form snubber.Adopt the quick-fried design of brill of the present invention, with the quick-fried design of traditional brill (the equal powder charge of all periphery holes, last arc guide snubber adopts rectangle to arrange, and not by last arc guide profiled outline arranged in form) compare one cubic metre of section of traditional explosion, need the 1.2-2.4Kg explosive, and the present invention only needs 0.6Kg, has significantly reduced the consumption of explosive, and can effectively reduce the disturbance of explosion wave to country rock, effectively control out break, minimizing is fallen piece, is caved in.The present invention adopts the microseismic activity controlled blasting excavation of short drilling depth, many jewel holes, few powder charge, and according to the occurrence of country rock joint, weak degree is in time adjusted the Tunnel Blasting parameter in practice of construction, has obtained best demolition effect.

The present invention is rock confined water tunnel when construction on the turn, anatomizes the geologic information that design provides, in conjunction with the advance geologic prediction data, and preliminary judgement front of tunnel heading country rock rank and underground water developmental state, surveying for advance borehole provides instruction; According to the preliminary judgement result, adopt advance borehole targetedly, accurately forecast; Advance borehole according to water yield size, is crept into spilled water hole after surveying in advance, makes the place ahead artesian water obtain in advance discharging, and reduces hydraulic pressure, for the back surface construction reduces difficulty; Use the ductule pre-grouting to reinforce country rock before the barrel excavation, form the grouting reinforcement circle, improve self, the most of underground water blocking of vault beyond the excavation outline line, is the construction operation condition that facilitates; Take the microseismic activity controlled blasting excavation of short drilling depth, many jewel holes, few powder charge, reduce of the disturbance of blasting impact ripple, improve the excavation effect, reduce and fall piece, cave in country rock; After preliminary bracing performs and finishes, perform radially ductule, be used as spilled water hole and sluice early stage, slows down the destruction of artesian water to preliminary bracing, in case the preliminary bracing strain cracking or be about to lining cutting before, then carry out radially grouting reinforcement rock and water blockoff once more by ductule radially.

In a word, the characteristics that the present invention is directed to artesian water are taked " visit-letting out-block up-arrange-block up " series of measures, have effectively controlled the harm and the destruction of artesian water, have improved execution conditions, have guaranteed construction quality and construction safety, have improved construction speed; This method is taked radially grouting reinforcement rock of ductule pre-grouting and ductule at the lithological characteristic of metamorphic rock simultaneously, has improved rock mass structure effectively, has improved self; Take the microseismic activity controlled blasting of short drilling depth, many jewel holes, few powder charge, reduced of the disturbance of blasting impact ripple effectively, improved the excavation effect, reduced and fallen piece, cave in country rock.After taking this worker method construction, the excavation profile has obtained effective control, falls piece and caves in and reduced occurrence frequency and dwindled scale, and the preliminary bracing strain cracking has obtained effective control, does not carry out secondary again and changes arch, has avoided Tunnel Landslide substantially.Average every linear meter(lin.m.) reduces the 4m that backbreaks after taking this worker method ³, reduce the sprayed mortar 4m that backbreaks ³, about 3500 yuan of minimizing expense; Every linear meter(lin.m.) decreased average disposes that piece caves in and about 3000 yuan of preliminary bracing strain cracking and landslide expense; Every linear meter(lin.m.) on average increases expense about 5000; Add up to about 1500 yuan of every linear meter(lin.m.) decreased average expense, take this worker method not only to reduce expense, and improved construction quality and construction safety effectively, thereby also created good social benefit, be applicable to all metamorphic rock confined water tunnel constructions.

Description of drawings

Fig. 1 is a construction technology process block diagram of the present invention;

Fig. 2 is metamorphic rock confined water tunnel three benching tunnelling method working procedure figure of the present invention;

Fig. 3 is leading inspecting hole of the present invention and leading spilled water hole layout schematic diagram;

Fig. 4 is a monitoring measurement measuring point arrangement diagram of the present invention;

Fig. 5 is the quick-fried plan of brill of metamorphic rock confined water tunnel excavation face of the present invention

Fig. 6 is the periphery hole charge constitution schematic diagram among Fig. 5;

Among the figure: the leading inspecting hole of 1-; The leading spilled water hole of 2-; 3-tunnel excavation outline line; The leading ductule of 4-; 5-is ductule radially; The 6-periphery hole; The 7-detonating fuse; The last arc guide of 8-; The 9-snubber; Lead A among the 10-; Lead B among the 11-; Lead C under the 12-; Lead D under the 13-; 14-inverted arch E; 15-partly rolls up emulsion; The 16-stemming; The 17-non-electric ms detonator.

The specific embodiment

A kind of job practices of metamorphic rock confined water tunnel as shown in Figure 1, may further comprise the steps:

A tentative prediction country rock rank and underground water developmental state: big or special geological structure and basic geological condition generally all can be indicated on the geologic information that design provides, by the TSP203 geological prediction system to tunnel geology segmentation in time predict, can predict soon construction section relatively accurately and land matter structure and underground water developmental state.Draw preliminary conclusion by anatomizing design geologic information and TSP system forecast data, and whether implement or which section to take leading inspecting hole to predict instruction is provided in for next step.Because the metamorphic rock confined water tunnel joint is intensive, rock crusher is rich in crevice water, the TSP system prediction is limited in scope, and in order to improve the forecast accuracy, requires every 80m prediction once;

Inspecting hole accurately forecasts geological condition and underground water developmental state before the B ultrasonic: according to the tentative prediction conclusion, survey at having artesian water or Fu Shui location and complicated geology location to take horizontal drill to carry out advance borehole, accurately judge the country rock lithology by the core sampling, architectural feature, accurately judge underground water developmental state and pressure condition thereof by the inspecting hole water yield, thereby for taking which kind of job practices in the tunnel, which kind of support form and supporting parameter and whether take advance borehole to sluice and make accurate judgement, leading inspecting hole 1 adopts RPD-150C rig Φ 110mm drill bit to drill, every 50m probing once, each probing 60m, described RPD-150C rig is existing known equipment;

C advance borehole sluicing step-down: rich water and artesian water location are taked advance borehole sluicing step-down according to the advance borehole result of detection, also can further verify geological condition and provide the guidance foundation for construction, leading spilled water hole 2 adopts XY-2PC rig Φ 91mm drill bit to hole, every 25m boring once, drilling depth 30m, 3～7 of each borings, leading inspecting hole and leading spilled water hole position are arranged and are seen Fig. 3, according to spilled water hole water yield and hydraulic pressure decision spilled water hole number, but 3 holes of subdrilling originally, if water yield is big, then bore 4 holes again, described XY-2PC rig is existing known equipment;

Leading grouting with small pipe concretion marginsing rock of D and water blockoff: in 120～180 scopes of barrel arch, perform leading ductule 4 along tunnel excavation outline line 3, cementing-water glass biliquid slurry, concretion marginsing rock improves self on the one hand, in addition can be beyond the excavation outline line with the most of underground water blocking in arch for forming the grouting reinforcement circle, under go on foot the construction operation condition that facilitates.The pre-grouting ductule adopts Φ 42*4 seamless steel pipe to be processed into the taper floral tube, and length is not less than 250cm, circumferential distance 30cm, and ring is not less than 100cm with ring level overlap joint.The cement-sodium silicate double liquid parameter: cement grout water ash weight ratio is 1: 1, mortar water glass volume ratio is 1: 0.8, modulus of water glass m=2.4～3.4, concentration Be=30～40, grouting pressure is controlled at 0.5～1.0MPa, and grout spreading range is not less than 30cm; Above-mentioned grout coordinate ratio and grouting parameter are that the applicant gets through long-term engineering practice and summary of experience, have guaranteed slip casting effect, and country rock is fixed and water plugging effect is fine;

E selects the barrel digging mode and determines the preliminary bracing form: through advance borehole sluicing and ductule pre-grouting, metamorphic rock confined water tunnel is by three benching tunnelling methods or go up arc guide and reserve core soil three benching tunnelling methods and construct, and carries out the preliminary bracing of corresponding form simultaneously; The above profile steel frame of I18, spacing 80～100cm are adopted in preliminary bracing; System anchor bolt adopts length to be not less than Hollow grouting anchor, 80 * 80cm quincuncial arrangement; Dowel circumferential distance 100cm, both sides interlaced arrangement inside and outside the steelframe; Steel mesh reinforcement adopts Reinforcing bar processing, grid 15 * 15cm; Adopt the C25 sprayed mortar, thickness is not less than 20cm.The preliminary bracing parameter also can perform by design standard, but must not be lower than These parameters.Excavation and supporting will perform in strict accordance with code requirement, guarantee construction quality.

Above-mentioned three benching tunnelling method working procedures are as follows, as shown in Figure 2:

A, after the leading pre-slip casting intensity of ductule reaches, by the construction principle of " short drilling depth, strong supporting ", arc guide 8 on the excavation, and perform preliminary bracing I portion, cyclic advance 80～100cm;

B, go up the leading 3～5m of arc guide and lead construction in beginning, lead in the staggered excavation A and in lead B, and lead preliminary bracing II portion and III portion in performing, about two priorities must not interlock less than 2m, the length of at every turn constructing must not surpass two Pin bow members (160～200cm);

C, in lead leading 3～5m and lead construction under beginning, interleaved dig down lead C and under lead D, and lead preliminary bracing IV portion and V portion in performing, about two priorities must not interlock less than 2m, the length of at every turn constructing must not surpass two Pin bow members (160～200cm);

F performs radially ductule: in order to prevent preliminary bracing exhalant canal is sealed, hydraulic pressure is increased, cause the preliminary bracing strain cracking, perform radially ductule 5 after supporting in the early stage performs and finishes; Radially ductule adopts Φ 42*4 seamless steel pipe to be processed into the taper floral tube, and length is not less than 250cm, 2.5 * 2.5m quincuncial arrangement.Radially ductule in earlier stage sluice as spilled water hole, preliminary bracing is in case cracking or be about to lining cutting then by ductule cementing-water glass biliquid slurry, is further reinforced country rock and water blockoff, and slurries cooperate when grouting pressure to carry out by leading pre-grouting with micropipe;

G excavation inverted arch is also built the inverted arch concrete: after the barrel excavation supporting is finished, immediately carry out inverted arch E (14) construction, the inverted arch construction is once excavated and concreting VI length must not surpass 6m, inverted arch preliminary bracing, inverted arch and inverted arch fill concrete want the layering view picture to build, and every construction technology of inverted arch and technical indicator must satisfy design or code requirement;

H performs secondary lining VII: before inverted arch construction the finishing lining cutting, by the cement-sodium silicate double liquid described in the ductule perfusion step D, further reinforce country rock and water blockoff.Take shop extension PE band drain and draining blind pipe to concentrate ejectment to the big position of water percolating capacity before the splash guard of shop.Splash guard adopts thickness to be not less than the PVC compound water-proof of 1.5mm, and strict control splash guard construction technology is strictly on guard against that sharp-pointed object such as reinforcing bar punctures splash guard, guarantees the splash guard construction quality, is strictly on guard against secondary lining percolating water.The secondary lining concrete adopts full section hydraulic lining trolley monobloc cast.Every construction technology of lining cutting and technical indicator must satisfy design or code requirement;

The I Blasting Excavation: metamorphic rock confined water tunnel excavation face adopt three step microseismic activity controlled blasting methods (promptly according to last arc guide, in lead, lead down three steps) excavation, when boring quick-fried design, all periphery holes 6 of arranging along the excavation outline line adopt detonating fuse 7 series connection, periphery hole adopts the spaced loading form, as shown in Figure 5, indicate 13 periphery hole powder charge, the periphery hole of not marking numeral is only put detonating fuse, periphery hole carries out powder charge according to shown in Figure 6, and is as shown in table 1 below according to the powder charge table of the quick-fried plan of above-mentioned brill; During last arc guide 8 explosions, according to last arc guide profiled outline arranged in form snubber 9, as shown in Figure 5, the borehole that indicates numeral 3,5,7 is a snubber, as seen from the figure, the empty eye at the above arc guide of its arrangement form center is the center, disperses symmetric arrangement to its both sides, and arrange with the spread pattern of 3 snubbers, 2 two snubbers and 1 snubber from inside to outside, form the shape that matches with last arc guide profiled outline, adopt the quick-fried design of this kind brill, both can reduce dosage, reduce the disturbance of explosion wave, and can obtain best demolition effect again country rock.

Table 1

In above-mentioned activities, control measurement work must be immediately following excavation, the supporting operation is layouted and monitor, and metric data application engineering analogy method is in time analyzed, fed back, and adjusts supporting parameter, and to guarantee construction and structural safety, specific practice is as follows:

Measure section for one group every 10m cloth when the rock confined water tunnel is constructed on the turn, each section arranges that a vault deflection measuring point and two horizontal clearances convergences measure baselines.Measuring point arranges that as shown in Figure 4 wherein a is a vault deflection measuring point, and b, c are respectively two horizontal clearance convergences and measure baseline.

The headroom horizontal convergence measures and vault sinks to measuring and adopts identical measurement frequency, measure frequency and see Table 2, the actual amount measured frequency from table according to rate of strain and apart from excavated surface apart from selecting a higher measurement frequency.Horizontal convergence measures and adopts the laser profiler to measure, and measuring point and numbering are installed rapidly behind the excavation on request, reads initial reading behind excavation in the 12h.Vault sinks to measuring to adopt laser profiler and precision level, convergence gauge, an indium watt chi to measure, and sets up an office at vault rapidly behind the sprayed mortar.

Table 2

In order further to prove the beneficial effect of this job practices, the applicant enumerates following case history and is proved:

Open collection railway Jiu Bao tunnel and be positioned at thing complicated structure band south, the Yinshan Mountains, in towards subsiding belt, the paraplatform Yanshan Mountain and Inner Mongol earth's axis boundary.On earth history, experienced the presinian period, the significantly tectonic movement of Mesozoic Era and three phases of new generation, the tectogenetic stack of many phases causes geological structure extremely complicated.The barrel scope is the Archaean group metamorphic rock, based on granulite and shallow particle rock, and local granite peamatite and the diabase vein of invading.Because of the difference of protolith composition and suffer the tectogenetic influence of many phases, cause tectonic joint cranny development degree difference, the cutting iris action of the intrusion of phase vein and fracture more than adding has formed the moisture and water proof structure in part location and layer position, thereby has formed artesian aquifer.The tunnel surrounding characteristics are that joint fissure is grown, joint plane is intensive, smooth, rock is bulk or chunky shape crush texture, rock monomer intensity height, and be mingled with the weak charges of thin layer, the country rock globality is poor, and a little less than the self-stable ability, the multilayer artesian water causes barrel excavation back not have water water outlet in a few days at that time and became big gradually with regard to water outlet and after becoming big or excavation gradually.

Above-mentioned collection railway Jiu Bao tunnel is metamorphic rock confined water tunnel, adopts conventional construction method in work progress, has the problem of being put down in writing in the background technology of the present invention.And after adopting method of the present invention, the excavation profile has obtained effective control, falls piece and caves in and reduced occurrence frequency and dwindled scale, and the preliminary bracing strain cracking has obtained effective control, does not carry out secondary again to change arch, has avoided Tunnel Landslide substantially.Opening collection railway Jiu Bao tunnel is 5385m by the metamorphic rock confined water tunnel cumulative length of this worker method organizing construction, about 8,070,000 yuan of accumulative total minimizing expense.

Claims (2)

1. the job practices of a metamorphic rock confined water tunnel is characterized in that may further comprise the steps:

A tentative prediction country rock rank and underground water developmental state;

Inspecting hole accurately forecasts geological condition and underground water developmental state before the B ultrasonic: according to the tentative prediction conclusion, survey at having artesian water or Fu Shui location and complicated geology location to take horizontal drill to carry out advance borehole, accurately judge country rock lithology, architectural feature by the core sampling, accurately judge underground water developmental state and pressure condition thereof by the inspecting hole water yield, leading inspecting hole (1) adopts RPD-150C rig Φ 110mm drill bit to drill, every 50m probing is once drilled 60m at every turn;

C advance borehole sluicing step-down: rich water and artesian water location are taked advance borehole sluicing step-down according to the advance borehole result of detection, leading spilled water hole (2) adopts XY-2PC rig Φ 91mm drill bit to hole, every 25m holes once, and drilling depth 30m holes 3～7 at every turn;

Leading grouting with small pipe concretion marginsing rock of D and water blockoff: in 120 °～180 ° scopes in barrel arch, perform leading ductule (4) along tunnel excavation outline line (3), cementing-water glass biliquid slurry, the cement-sodium silicate double liquid parameter: cement grout water ash weight ratio is 1: 1, mortar water glass volume ratio is 1: 0.8, modulus of water glass m=2.4～3.4, concentration Be=30～40, grouting pressure is controlled at 0.5～1.0MPa, and grout spreading range is not less than 30cm;

E selects the barrel digging mode and determines the preliminary bracing form: through advance borehole sluicing and ductule pre-grouting, metamorphic rock confined water tunnel is by three benching tunnelling methods or go up arc guide and reserve core soil three benching tunnelling methods and construct, and carries out the preliminary bracing of corresponding form simultaneously;

F performs radially ductule: perform radially ductule: perform radially ductule (5) after supporting in the early stage performs and finishes;

G excavation inverted arch is also built the inverted arch concrete: after the barrel excavation supporting is finished, carry out inverted arch E construction immediately, the inverted arch construction is once excavated and concreting length must not surpass 6m;

H performs secondary lining: before inverted arch construction the finishing lining cutting, by the cement-sodium silicate double liquid described in the ductule perfusion step D.

2. the job practices of a kind of metamorphic rock confined water tunnel according to claim 1, it is characterized in that metamorphic rock confined water tunnel excavation face adopts three step microseismic activity controlled blasting methods excavation, when boring quick-fried design, all periphery holes (6) of arranging along the excavation outline line adopt detonating fuse (7) series connection, and periphery hole adopts the spaced loading form; During last arc guide (8) explosion, according to last arc guide profiled outline arranged in form snubber (9).