The especially big dome excavation construction method of underground chamber
Technical field
The present invention relates to underground cavern excavation construction field, particularly the especially big dome excavation construction method of a kind of underground chamber.
Background technology
In underground excavation engineering, be designed with dome-shaped, i.e. crown curved underground chamber spherical in shape, the surge shaft in such as power station.For middle-size and small-size class dome-shaped cavern, the usual span of arch (i.e. dome diameter) is less than 12m, the construction method at dome position mainly contains pilot tunnel method, cross excavating load, fan-shaped stick method, annular center pillar method etc., but for the dome position of especially big dome-shaped underground chamber, the such as dome of the span of arch more than 20 meters, according to these construction methods, there is working space narrow, each operation is disturbed greatly mutually, it is larger that shot hole explosive payload controls difficulty, the yielding instability of country rock, constructing operation is extremely inconvenient, the shortcomings such as Arch Excavation forming quality is wayward, be difficult to adopt large-scale excavation, support apparatus, therefore work efficiency is low, duration not easily ensures, construction cost is large.
" Chinese Water Conservancy Hydroelectric Project Construction " 2011. first phase 24-27 page describe " Huizhou Pump-storage Plant down stream surge tank dome excavation construction ", have employed the method for circumferentially boring lateral aperture and carry out excavation construction, obtain good excavation molding effect.Such as, but when adopting the method, operating space relative narrowness, is unfavorable for adopting Large Construction facility, bores quick-fried chassis etc., and when the span of arch is larger, such as reach 20m even 30m time, the height of cavern's dome is higher, construction inconvenience, inefficiency.
" Shanxi architecture " January the 3rd in 2008, phase 152-153 page described " blasting construction on silo dome of left bank mixing system of Xiaowan power station ", have employed with the constructure scheme of gallery symmetrical branch piecemeal, Problems existing is, when the diameter of cavern's dome becomes large, such as, when reaching 30 meters, now the height of cavern's dome is higher, and construction is difficulty comparatively, and construction risk increases.
Summary of the invention
Technical problem to be solved by this invention is to provide the especially big dome excavation construction method of a kind of underground chamber, multiple work plane can be realized construct simultaneously, and working space is larger, be suitable for adopting large-scale excavation, support apparatus to construct, reduce difficulty of construction and security risk, and each operation is disturbed mutually little, Arch Excavation forming quality is easy to control, work efficiency is higher, and construction cost is lower.
For solving the problems of the technologies described above, the technical solution adopted in the present invention is: the especially big dome excavation construction method of a kind of underground chamber, comprises the following steps:
One, by dome cavern and the pilot tunnel that is attached thereto by upper lower leaf;
Two, by dome cavern with pilot tunnel for be divided into multiple section axisymmetrically;
Three, excavate the pilot tunnel on upper strata, after pilot drive, by designing requirement, system supporting is carried out to its crown position; With the vertical axis of dome cavern for axisymmetry, and with pilot tunnel axis for each section of the staggered excavation of axis of symmetry symmetry, and progressively away from this vertical axis, after the excavation of single section, by designing requirement, system supporting is carried out to dome crown, in digging process, the location poor to local geological conditions, can take temporary lining measure at random;
Four, excavate the pilot tunnel of lower floor, after pilot drive, by designing requirement, system supporting is carried out to its side wall; With the vertical axis of dome cavern for axisymmetry, and with pilot tunnel axis for each section of the staggered excavation of axis of symmetry symmetry, and progressively away from this vertical axis, after the excavation of each section, by designing requirement, system supporting is carried out to dome crown, in digging process, the location poor to local geological conditions, can take temporary lining measure at random;
The especially big dome excavation construction of underground chamber is realized by above-mentioned steps is safe and efficient.
In step 2, section, the upper strata quantity of division is more than the quantity of lower floor section.
In step 4, be also provided with the topping of annular outside each section and between dome design profile line, topping is constructed after inner section has been excavated again.
In step 3 and four, the work plane of simultaneously constructing must not more than two.
In step 3 and four, adopt the independence explosion of monolithic district during explosion, forbid multiple scope of operation to implement explosion simultaneously.
In step 3, upper strata excavation adopts and bores the boring of quick-fried chassis cooperation artificial hand air drill, and boring aperture is φ 42 ± 3mm, slotting is taked to excavate, main explosion hole drill lateral aperture, the perimeter hole in contiguous dome crown outline line region, as far as possible along the boring of outline line direction hand air drill, adopts smooth blasting method.
In described smooth blasting, breaking hole pitch-row is with 1 ± 0.1m, and perimeter hole pitch-row is with 0.5 ± 0.05m, and excavation cyclic advance controls at 1.5 ± 0.15m.
In step 4, lower floor's excavation adopts down-the-hole drill boring, coordinates heading blast method.
In step 4, the lower floor's pilot tunnel in dome cavern is also provided with one section of reserved slope, and the exit end wherein near pilot tunnel is higher, and described reserved ramp slope is 12%.
In step 4, the described last excavation construction in reserved slope, or together with the well bore part of bottom, dome cavern excavation construction.
The especially big dome excavation construction method of a kind of underground chamber provided by the invention, compared with prior art has following beneficial effect:
1, cavern surrounding rocks is carried out layering, subregion according to the principle of " breaking the whole up into parts, partial excavation ", thus reduce excavation span, reduce difficulty of construction and security risk.
2, same layer rock mass follows the principle of " left and right diagonally opposing corner wrong cross section simultaneously construct ", and according to the sequencing excavation construction determined, two work planes can operation simultaneously, and each operation is disturbed little mutually, is conducive to improving work efficiency, reducing Construction Cost.
3, be close to the perimeter hole in dome outline line region, adopt along outline line hoop horizontal bore mode, be both conducive to convenient working human users, be also easy to the forming quality ensureing that dome outline line once excavates.
4, after dome lower floor pilot drive completes, because the supporting of upper strata dome completes, during the rock excavation of its both sides, working space is larger, is easy to adopt large-scale excavation supporting equipment, and in conjunction with the construction of heading blast method, is conducive to increasing work efficiency further.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described:
Fig. 1 is the vertical section structure schematic diagram of dome cavern in the present invention.
Fig. 2 is the A-A cross-sectional schematic of Fig. 1, and what show in figure is point section schematic diagram on upper strata.
Fig. 3 is the present invention's sequence of excavation of section and tunneling direction schematic diagram at the middle and upper levels.
Fig. 4 is the schematic diagram of the present invention's pilot drive at the middle and upper levels.
Fig. 5 is the B-B cross-sectional schematic of Fig. 4.
Fig. 6 is the C-C cross-sectional schematic of Fig. 1, and what show in figure is point section schematic diagram of lower floor.
Fig. 7 is the vertical section schematic diagram of lower floor section excavation in the present invention.
Fig. 8 is lower floor section sequence of excavation and tunneling direction schematic diagram in the present invention.
In figure: stratification line 1, pilot tunnel 2, the second layer 3, first floor 4, reserved slope 5, topping 6, system supporting 7, dome cavern 8.
Detailed description of the invention
As in Fig. 1 ~ 8, the especially big dome excavation construction method of a kind of underground chamber, comprises the following steps:
One, by dome cavern 8 and the pilot tunnel 2 that is attached thereto by upper lower leaf; Specifically as shown in fig. 1, in this example, dome cavern 8 and pilot tunnel 2 are divided into two-layer.As shown in Figure 1 with stratification line 1 be boundary first floor 4 and the second layer 3.Sequence of construction in design first excavates first floor 4, then excavate the second layer 3, thus construction height is controlled in the scope of constructability.In this example, upper and lower two layer heights of pilot tunnel 2 are roughly equal.
Two, by dome cavern 8 with pilot tunnel 2 for be divided into multiple section axisymmetrically; Concrete as shown in Fig. 2,6, in Fig. 2, be divided into 9 sections, in Fig. 6, be divided into 6 sections, such as, I-1 ~ I-5' section in Fig. 2, II in Fig. 6-1 ~ II-4' section.As can be seen from the figure, the scheme of optimization, as in step 2, section, the upper strata quantity of division is more than the quantity of lower floor section.This is because when lower floor section and the second layer 3 are constructed, section, upper strata and first floor 4 have excavated and have completed the system supporting 7 of crown, security risk is relatively little, working space is larger, therefore larger section can be divided into, be convenient to adopt down-the-hole drill boring, coordinate heading blast method, with further accelerating construction progress.
Three, the pilot tunnel 2 on upper strata is excavated, the width of pilot tunnel 2 and highly general 1/4 ~ 1/3 control according to the span of value.First excavate upper strata pilot tunnel 2, dome is divided into left and right two parts by pilot tunnel centrally line symmetrically; In pilot drive construction, after face enters dome region, its Arch Excavation line gradually changes along dome design profile line is curved, specifically as shown in Figure 4; After pilot drive, to crown and side wall position, by designing requirement implementation system supporting 7, except the side wall in dome region herein.In digging process, the location poor to local geological conditions, can take temporary lining measure at random, and its working procedure and method are implemented with reference to existing conventional method.
With the vertical axis of dome cavern 8 be shaft staggered symmetry excavation each section, and progressively away from this vertical axis, be specially sequence of excavation as shown in Figure 3 and tunneling direction, construct I-2 and I-2 successively simultaneously ', I-3 and I-3 ', I-4 and I-4 ' and I-5 and I-5 '.Namely staggered symmetrical with vertical axis or be called and similarly construct with rotational symmetric two sections of vertical axis simultaneously, wrong cross interlocks construction method thus, and guarantee that two sections of simultaneously constructing do not interfere with each other, especially construction equipment and transport do not interfere with each other.Adopt progressively away from the form of construction work of the form of construction work cooperation stage excavation of vertical axis, further ensure that excavation construction safety, and efficiency of construction is high, is especially convenient to the scheduling of engineering truck.
The work plane of simultaneously constructing must not more than two, to excavate when preorder section and after system supporting is carried out by designing requirement to dome crown, in digging process, the location poor to local geological conditions, temporary lining measure can be taked at random, to construct successively follow-up section, until dome first floor 4 all construction is complete.
In step 3, upper strata excavation adopts and bores the boring of quick-fried chassis cooperation artificial hand air drill, and boring aperture is φ 42 ± 3mm, slotting is taked to excavate, main explosion hole drill lateral aperture, the perimeter hole in contiguous dome crown outline line region, as far as possible along the boring of outline line direction hand air drill, adopts smooth blasting method.
In described smooth blasting, preferred breaking hole pitch-row is advisable with 1 ± 0.1m, continuously dress diameter phi 32mm emulsification powder stick; Perimeter hole pitch-row is advisable with 0.5 ± 0.05m, and select φ 25mm emulsification powder stick, spaced loading, line density is preferably advisable with 110 ~ 130g/m, or actual blasting parameter can be determined further according to on-the-spot explosion bulge test.As in Fig. 3, arrow points is preferred tunneling direction, and excavation cyclic advance controls at 1.5 ± 0.15m.
Four, excavate the pilot tunnel 2 of lower floor, and extend in dome, after the pilot tunnel 2 of lower floor has excavated, by designing requirement, supporting is carried out to the side wall of pilot tunnel 2, except the side wall in dome region herein.
With the vertical axis of dome cavern 8 be shaft staggered symmetry excavation each section, and progressively away from this vertical axis, be specially the sequence of excavation shown in Fig. 8 and tunneling direction, construct II-2 and II-2 successively ', II-3 and II-3 ' simultaneously, namely construct with the vertical axis symmetrical Liang Ge district that interlocks, the work plane of simultaneously constructing must not more than two simultaneously.
Each section adopts down-the-hole drill boring, and boring aperture is φ 90 ± 9mm, and pitch of holes is advisable with 2 ± 0.2m; Adopt heading blast method, the preferred diameter phi 70mm of dress continuously emulsification powder stick, or actual blasting parameter can be determined according to on-the-spot explosion bulge test.
In this step; the scheme optimized, is also provided with II-4 section in reserved topping 6(and Fig. 6 of annular outside each section and between dome design profile line), reserved topping 6 is constructed after inner section excavation is complete again; scheme thus, is beneficial to the shaping of crown curved-surface structure.In step 4, lower floor's pilot tunnel 2 in dome cavern 8 is also provided with one section of reserved slope 5, namely as shown in Figure 7 II-5, exit end wherein near pilot tunnel 2 is higher, described reserved slope 5 gradient is 12%, the setting on reserved slope 5, has both been conducive to plant equipment and has passed through, also reduce the projected depth of pilot tunnel, save the open excavation amount of pilot tunnel.II-4, II-5 district implements with reference to the quick-fried method of brill described in step 3 and smooth blasting method, and wherein said reserved slope 5 i.e. II-5 last excavation construction in section, or together with the well bore part of bottom, dome cavern 8 excavation construction.
After reserved topping 6 excavates, carry out system supporting to dome crown by designing requirement, in digging process, the location poor to local geological conditions, can take temporary lining measure at random.
The especially big dome excavation construction of underground chamber is realized by above-mentioned steps is safe and efficient.
Especially should be noted that, in step 3 and four, the independence explosion of monolithic district should be adopted during explosion, forbid multiple scope of operation to implement explosion simultaneously, further, each bursting work face is also take pilot tunnel as the operation of axis of symmetry individual interleaving, and to guarantee construction safety further, such as, preferred blasting sequence shown in Fig. 5 is (1) → (2) ... (18).