CN116104530A - Poor geological disaster construction method for diversion tunnel - Google Patents
Poor geological disaster construction method for diversion tunnel Download PDFInfo
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- CN116104530A CN116104530A CN202211177707.0A CN202211177707A CN116104530A CN 116104530 A CN116104530 A CN 116104530A CN 202211177707 A CN202211177707 A CN 202211177707A CN 116104530 A CN116104530 A CN 116104530A
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/04—Lining with building materials
- E21D11/10—Lining with building materials with concrete cast in situ; Shuttering also lost shutterings, e.g. made of blocks, of metal plates or other equipment adapted therefor
- E21D11/102—Removable shuttering; Bearing or supporting devices therefor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/14—Lining predominantly with metal
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
- E21D11/14—Lining predominantly with metal
- E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
- E21D20/02—Setting anchoring-bolts with provisions for grouting
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D9/00—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
- E21D9/006—Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries by making use of blasting methods
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
Abstract
The invention discloses a method for constructing undesirable geological disasters of a diversion tunnel, which comprises the following steps of stabilizing surrounding rocks at the upstream and downstream of an undesirable geological disaster area: performing supporting construction on upstream and downstream surrounding rocks in an undesirable geological disaster area; and (3) construction treatment of the poor geological disaster area: sealing the poor geological disaster area, and supporting the stressed body by the composite arch to strengthen the support, the deep support and the shallow support; establishing an integral supporting arch stress body formed by steel arch frame-mould spraying concrete-secondary backfilling; performing layered blasting excavation treatment on a rock plug section of a main tail water hole intersected with the diversion tunnel; and a safety detection early warning system is established to monitor surrounding rocks of the poor geological disaster area of the diversion tunnel in time so as to guide site construction. The construction method of the invention ensures the stability of the unfavorable geological disaster area, the stability of surrounding rock during excavation and the safety and stability of large-scale collapse areas of diversion tunnels, particularly the middle partition wall of the diversion tunnel with the super large section.
Description
Technical Field
The invention relates to the field of bad geological disaster construction. More particularly, the invention relates to a method for constructing a small-flow-hole good-geological disaster.
Background
In the construction power station of the high mountain gorge valley, a tunnel diversion mode is generally adopted, and along with the continuous expansion of the construction scale of the hydropower station, the scale of a diversion underground cavity is gradually increased and complicated, and geological conditions are also gradually complicated. Moreover, due to the shortage of energy, the requirements for early production of the hydraulic and hydroelectric engineering construction are becoming stronger, and the construction period is gradually shortened. Diversion tunnel is the control construction period of river closure, and the general construction period is extremely tense. How to adapt to the condition of extremely complex geological surrounding rock in extremely short construction period becomes an unavoidable problem in the construction of the underground cavern at present.
On the basis of building up the underground holes such as the left shore diversion tunnel, the mall screen diversion tunnel and the underground factory building of the land, the technology innovation is carried out in the construction of the right shore diversion tunnel of the Wu Dongde hydropower station, aiming at the poor geological section of the Wu Dongde special thin layer to the ultra-thin layer limestone, the problem of unloading and loosening stability of the excavated rock mass is extremely prominent, the self-stabilization time of surrounding rock is short, collapse, peeling off along the layer and other damages easily occur, and the disturbance and deformation of the large-section rock, the prevention of the reinforcement of the rock mass, the large collapse and the like are all the problems to be solved urgently in the construction process.
Disclosure of Invention
It is an object of the present invention to solve at least the above problems and to provide at least the advantages to be described later.
The invention also aims to provide a method for constructing the poor geological disaster of the diversion tunnel, which guarantees the stability of the poor geological disaster area of the diversion tunnel, the stability of surrounding rock during excavation, strictly controls excavation footage to excavate quality, adopts a targeted reinforcement treatment process aiming at a series of special poor geology encountered in the construction process, establishes a monitoring, measuring, analyzing and feedback system to check the rationality of the construction process and design parameters, and ensures the safety and stability of the poor geological disaster area in the diversion tunnel.
To achieve these objects and other advantages and in accordance with the purpose of the invention, there is provided a method for constructing a poor geological disaster of a diversion tunnel, comprising the steps of:
step one, stabilizing surrounding rocks at the upstream and downstream of a bad geological disaster area: performing supporting construction on upstream and downstream surrounding rocks in an undesirable geological disaster area;
step two, construction treatment of a poor geological disaster area: sealing the poor geological disaster area, and supporting the stressed body by the composite arch to strengthen the support, the deep support and the shallow support;
thirdly, establishing an integral supporting arch stress body formed by steel arch frame-mould spraying concrete-secondary backfilling;
fourthly, performing layered blasting excavation treatment on the rock plug section of the main tail water hole intersected with the diversion tunnel;
and fifthly, establishing a safety detection early warning system to monitor surrounding rocks of the poor geological disaster area of the diversion tunnel in time so as to guide site construction.
Preferably, the first step specifically includes: the guide hole middle partition wall is provided with a plurality of rows of anchor ropes which are penetrated in pairs, the left side wall is provided with a plurality of rows of anchor bar piles, and the right side wall is provided with a plurality of rows of anchor bar piles.
Preferably, the second step specifically includes the following steps:
s1, sealing: c25 coarse fiber concrete with the thickness of 15cm is sprayed on the cracking part system of the concrete spraying layer of the upstream side wall and the downstream side wall of the poor geological disaster area for primary sealing; arranging a hole outside slag pulling foot protector on a side wall of a poor geological disaster area, and adding a reinforced gabion on a side of a channel of the poor geological disaster area to protect slag piling feet;
s2, reinforcing and supporting the composite arch supporting stress body: supporting the diversion tunnel by using a supporting steel, and simultaneously performing system concrete spraying treatment;
s3, deep layer support and shallow layer support: and (3) carrying out reinforced supporting treatment of combining the anchor bar piles with the anchor cable deep and shallow layers on the poor geological disaster section, and simultaneously carrying out systematic consolidation grouting construction on the whole side slope by adopting the anchor bar piles and the anchor cable holes.
Preferably, the third step specifically includes the following steps:
1) According to the structural characteristics of the diversion tunnel cross section cavity, the middle layer of the diversion tunnel is excavated in a thin layer excavation mode from top to bottom, and the two rear sides are excavated in an expanding excavation mode; and timely sealing surrounding rocks and the face around the excavated area;
2) Carrying out anchor bolt support on the closed surrounding rock, and carrying out steel arch installation, steel bar net hanging and disassembly-free template installation;
3) And performing mould spraying concrete between the installed steel arch and the surrounding rock face, and filling gaps by adopting secondary backfilling grouting or pumping concrete, so that the steel arch, the mould spraying concrete and the backfilling concrete form an integral supporting arch stress body.
Preferably, the anchor cables are arranged in 4 rows, and the interval is 4 x 4m; the anchor piles arranged on the left side wall and the right side wall are all 6 rows, and the interval row spacing is 2.5 multiplied by 2.5m.
Preferably, the size of the reinforced gabion is 3 multiplied by 1m, the row distance between the reinforced gabions is 20cm multiplied by 20cm, the diameter of the main reinforcement is 22mm, and the diameter of the web reinforcement is 14mm.
Preferably, the supporting the steel support in the diversion tunnel in the step S2 specifically includes: the diversion tunnel side wall is provided with 120b I-steel which is welded with anchor rods arranged in the side wall, the I-steel is longitudinally provided with connecting channel steel, and the circumferential spacing is 1.5m.
Preferably, in the step 1), the timely sealing of surrounding rocks and the tunnel face around the excavated area includes: and spraying a layer of 5-8 cm steel fiber concrete on the surrounding rock and the face to seal.
Preferably, the step four specifically includes: the middle 6-7 m bench shallow Kong Lacao is adopted, 4-5 m protection layers are reserved on two sides, vertical light explosion follow-up excavation is adopted for the protection layers, movable standard sample frames are all erected on vertical light explosion holes, hand air drill drilling is carried out, vertical light explosion is carried out, and the single-shot dosage is controlled within 10 kg.
The invention at least comprises the following beneficial effects:
firstly, the method for constructing the poor geological disaster of the diversion tunnel comprises the steps of stabilizing surrounding rocks at the upstream and downstream of a collapse area before the poor geological area is processed, and processing the poor geological area after the stress of the collapse area is stabilized.
Secondly, the method for constructing the poor geological disaster of the diversion tunnel adopts a technology of 'fast sealing, composite arch supporting and stressing body reinforcing support, deep layer support and shallow layer support merging' aiming at the poor geological area, so that the stability of the poor geological area is ensured.
Thirdly, the construction method for poor geological disasters of the diversion tunnel, disclosed by the invention, is particularly used for carrying out collapse treatment on the middle partition wall of the diversion tunnel with an extra-large section, and has the advantages that the support steel is adopted in the tunnel, and the concrete is sprayed in the system for treatment, so that the rock mass is effectively reinforced, and a good supporting effect is achieved on the side wall.
Fourth, in the method for constructing the poor geological disaster of the diversion tunnel, the poor geological area collapse body is subjected to reinforcing and supporting treatment measures of combining deep layers and shallow layers such as anchor rib piles and anchor cables, and meanwhile, the anchor rib piles and anchor cable holes are utilized to carry out systematic consolidation grouting measures on the whole side slope, so that a good effect is achieved, and a good reinforcement effect is achieved on the rock mass around the poor geological disaster collapse body.
Fifth, in the method for constructing the small-scale geologic hazard of the diversion tunnel, the rock plug section of the main tail water tunnel intersected with the diversion tunnel is subjected to layered blasting excavation treatment, so that disturbance and deformation of blasting on the rock with a large section are reduced, and generation of large collapse is effectively prevented.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
FIG. 1 is a cross-sectional view of a steel support in the construction process of a composite arch support stress body reinforcement support according to the present invention;
FIG. 2 is a cross-sectional view of a cable penetration arrangement in the construction process of deep and shallow layer supports of the present invention;
FIG. 3 is a cross-sectional view of a self-advancing anchor rod/tendon pile support arrangement in a collapse zone in the construction flow of deep and shallow layer supports of the present invention;
FIG. 4 is a flow chart of a method of constructing a poor geological disaster of a diversion tunnel according to the present invention;
FIG. 5 is a main water hole arrangement structure diagram of a 3# diversion tunnel, a 4# diversion tunnel, a 5# and a 6# tail water.
Detailed Description
The present invention is described in further detail below with reference to examples to enable those skilled in the art to practice the same by referring to the description.
The experimental methods described in the following embodiments are conventional methods unless otherwise indicated, and the reagents and materials are commercially available.
Examples
The hydraulic power station Wu Dongde (Wu Dongde hydraulic power station is four water-electricity steps of Jinsha river downstream river reach (Panzhihua city to Yibin city) -Wu Dongde, white crane beach, xilodu, most upstream step in domestic dam, right bank of river reach of dam site belongs to Kunming city, luzhou province, yi Zhong county of Yunnan province, left bank belongs to Sichuan province, dong county of Yi province) is an I-class (1) engineering, the main junction engineering building consists of a water retaining building, a water draining building, a water diversion power generation building and the like, the power station building is arranged in the mountain bodies on the left and right banks and is arranged on the side of the river bed, 6 single-machine mixed-flow water turbine generator sets with 850MW capacity are respectively arranged, the capacity 10200MW of the general assembly machine is 401.1 hundred million kW.h, the normal water level 975m and the corresponding reservoir capacity 58.63 hundred million m 3 . The diversion system adopts one-machine one-hole and one-chamber one-hole arrangement, the left bank and the right bank are respectively provided with 2 tail water tunnels and diversion tunnels for combined) construction as an example,
the right bank of the Wu Dongde hydropower station is provided with 3 diversion tunnels in total, the tunnel body sections are arranged in parallel, the axial distance is 38 m-50 m, the net section of the 4# guide lining is 16.5 multiplied by 24.0m (width multiplied by height), the excavation size is 19.9 multiplied by 27.2, and the tunnel body outlet section is combined with the tail water tunnel of the power station. The right bank diversion tunnel surrounding rock body is composed of a fold substrate, and stratum passing through from an inlet to an outlet is sequentially: the civil groups Pt2yl, pt2y2 and the snowfall groups Pt211 and Pt2l8, wherein Pt2y1 is a flesh red interbedded thin layer and medium-thick quartz marble dolomite, pt213-2-4 and Pt213-4-2 are quartz rocks with the thickness of about 5m, and the rocks are hard. Formation production: the inclination angle is 160-180 degrees, the inclination angle is 65-85 degrees, and the inclination angle is downstream.
The rock mass at the collapse section of the diversion tunnel mainly has breeze, local crevice corrosion and efflorescence, yellowing of the bedding surface, poor cementation, local crumpling phenomenon of the tunnel wall, medium-slow inclined structural surface and micro-crack development, rock mass breaking and local drip infiltration phenomenon, and is IV-class surrounding rock. In addition, the hole section develops a group of long and large cracks with the width of 2-3 mm, the crack moves to the upstream of the gradual inclination of 350 DEG with the inclination angle of 25 DEG, mud and calcium in the crack are filled, and the crack and the layer are cut together to form an easily-unstable block. The excavating height of the side walls at the two sides of the No. 3 diversion tunnel and the No. 4 diversion tunnel of the Wu Dongde hydropower station is large, the middle partition wall between the two diversion tunnels is thinner, the thickness is only 30.5m, and the high side wall and the thin partition wall are easy to deform and unstably appear. After collapse, the intermediate wall only remains about 17m, and the remaining rock mass is basically in a plastic deformation area, so that the stability is extremely poor. In the process of treating the collapse body, the collapse of the intermediate wall is easy to occur, the whole collapse phenomenon of the intermediate wall occurs, the treatment and construction safety of the collapse area are extremely unfavorable, in addition, the collapse area is just positioned at the tail guide combination section, the intermediate wall at the later stage needs to be subjected to secondary blasting excavation and transformation, and the construction period of the diversion tunnel is extremely short, if the collapse area cannot be treated in the shortest time, the on-schedule overflow and the interception of the river are seriously influenced.
Large-area collapse of the side wall below the right arch angle of the pile number 1+220-1+270 of the No. 3 diversion tunnel occurs, the collapse height is about 20-22 m, the elevation is EL 799-EL 820m, the collapse depth is about 8-13 m, and the total collapse amount is about 4000m3. After collapse, the intermediate wall only remains about 17m, and the remaining rock mass is basically in a plastic deformation area, so that the stability is extremely poor.
Aiming at the technical problems existing in the construction project, the method for constructing the poor geological disaster of the diversion tunnel comprises the following steps (the flow chart is shown in figure 4):
step one, stabilizing surrounding rocks at the upstream and downstream of a bad geological disaster area: performing supporting construction on upstream and downstream surrounding rocks in an undesirable geological disaster area; the downstream tail guide combination section of the collapse area adopts a reinforcing supporting measure, 4 rows of opposite penetrating anchor cables are added to an intermediate wall of a 4# diversion tunnel 1+530.02-1+598.02m (the 3# diversion tunnel corresponds to pile numbers 1+402.373-1+470.373m), the anchor cables are constructed from the 4# diversion tunnel to the 3# diversion tunnel, the anchor cables adopt 1500KN, L=30.5m, and the interval is 4×4m; 6 rows of anchor piles are added to the left side wall of the 3# diversion tunnel 1+361.373-1+388.873m, the length L=18m, and the interval row spacing is 2.5X2.5m; 6 rows of anchor piles are added to the right side wall of the 4# diversion tunnel 1+477.3-1+607.3m, the length L=18m, the interval row distance is 2.5X2.5 m, 6 rows of anchor piles are added to the left side wall of the 4# diversion tunnel 1+600.5-1+610.5 m, the length L=18m, and the interval row distance is 2.5X2.5 m;
step two, construction treatment of a poor geological disaster area: sealing the bad geological disaster area, supporting the stressed body by the composite arch to strengthen the support, deep support and shallow support:
s1, sealing: c25 coarse fiber concrete with the thickness of 15cm is sprayed on the cracking part system of the concrete spraying layer of the upstream side wall and the downstream side wall of the poor geological disaster area for primary sealing; the hollow part of the collapse area is filled up to form an arc arch ring so as to strengthen the support; adopting out-hole slag pulling foot protection for the right side wall at the upstream side and the downstream side of the collapse area of the 3# diversion tunnel, adopting reinforcing steel bar gabions to protect the foot of slag pile on the lower right 5# branch hole side and the side of the channel leading to the collapse area, wherein the size of the reinforcing steel bar gabions is 3 multiplied by 1m, the row spacing between the reinforcing steel bars is 20cm multiplied by 20cm, the main reinforcement is phi 22mm, and the web reinforcement is phi 14mm;
s2, reinforcing and supporting the composite arch supporting stress body: supporting the vertical steel in the diversion tunnel, and simultaneously carrying out system concrete spraying treatment: i20b I-steel is added to the right side wall of the range of 1+160-1+320m of the 3# diversion tunnel and the position below the arch angle of the left side wall of the 4# diversion tunnel 1+330-1+450, the distance is 1.25m as same as that of a system anchor rod, the I-steel is welded with the side wall system anchor rod, a [ 12-connection channel steel is longitudinally arranged between the I-steel, the circumferential distance is 1.5m, the I-steel is welded firmly with the system anchor rod as far as possible, the welding position with the system anchor rod cannot be realized, 4 phi 25I-steel plates are arranged on each I-steel plate, and L=3m pin locking anchor rods are arranged. The steel supporting part is fully sprayed by C25 steel fiber concrete; a steel support section is shown in fig. 1;
s3, deep layer support and shallow layer support: according to the geological condition of the collapse section and the actual construction condition on site, the following treatment measures are mainly adopted for the collapse body.
(1) 3 rows of opposite-penetrating anchor cables (the pile numbers corresponding to the 4# diversion tunnels are 1+287.8-1+311.02m) are added below the right wall arch angle of the 3# diversion tunnels 1+160-1+183.15m, the row spacing between the anchor cables is 4 multiplied by 3m, holes are formed in the 4# diversion direction, the length of the anchor cables is about 30.5m, and 1000KN bonding type anchor cables are adopted. The anchor cable is characterized in that 4 rows of 3 phi 28 anchor bar piles are oppositely driven from 3# diversion tunnels and 4# diversion tunnels, the spacing is 2.5 multiplied by 2.5m, and the length L=18m of the anchor bar piles;
(2) 5 rows of opposite-penetrating anchor cables are added below the right wall arch angle of the 1+183.15-1+230 m of the 3# diversion tunnel (the corresponding pile number of the 4# diversion tunnel is 1+311.02-1+357.87 m); 5 rows of opposite-penetrating anchor cables are added below the right wall arch angle of the No. 3 diversion tunnel 1+270-1+320 m (the corresponding pile number of the No. 4 diversion tunnel is 1+397.87-1+447.87 m). The row spacing between anchor cables is 4 multiplied by 4m. The length of the anchor cable is about 30.5m, and 1000KN bonding type anchor cable is adopted; figure 2 is a cross-sectional view of a cable penetration arrangement;
(3) 8 rows of 3 phi 28 anchor piles with L=18m anchor pile angles are added below the left wall arch angle with the corresponding pile number of 1+357.87-1+397.87, the interval row distance is 2.5 multiplied by 2.5m, and the periphery of the hole wall is concreted and grouted by anchor pile holes.
(4) The 3 phi 28 anchor piles are added to the side walls at the two sides of the sections 1+230-1+311 of the 4# diversion tunnel, the interval row spacing is 2.5 multiplied by 2.5m, and the length is 18m.
(5) The original design support parameters of the pile number section of the 4# guide 1+350-1+398 are phi 28, L=6m/9 mortar anchor rods, the interval row distance is 1.25x1.25, the anchor rods of the middle-lower side wall are regulated to phi 28, L=6m/9 m self-advancing anchor rods, and the interval row distance is 1.25x1.25 m.
The original design support parameters of the anchor rod of the middle and lower side walls of the 4# diversion tunnel 1+398-1+450 sections are phi 25, L=4.5m, the interval row distance is 1.5x1.5m, the adjustment is phi 28, L=6/9 m, and the interval row distance is 1.25x1.25m self-advancing anchor rod;
the anchor rod of the lower side wall of the pile number 1+285-1+335 of the No. 5 diversion tunnel is adjusted to be a self-advancing anchor rod, the parameter is phi 28, L=9m, and the interval row distance is 1.25 multiplied by 1.25m; FIG. 3 is a cross-sectional view of a self-advancing anchor rod/anchor bar pile support arrangement in a positive collapse area;
(6) 2 rows of anchor bar piles are added to the left side wall of the No. 5 diversion tunnel 1+240-1+340, 4 rows of anchor bar piles are added to the right side wall and the arch angle part, the parameters are 3Φ28, L=18m, and the interval row spacing is 2×3m;
(7) 4 rows of 3 phi 28 anchor piles are added above 808m elevation of a left side wall of a section K1+220-K1+320 of the 3# diversion tunnel, 2 rows of 3 phi 28 anchor piles are added below 808m elevation, the interval row spacing is 2.5 multiplied by 2.5m, and the length is 18m;
(8) 5 rows of 3 phi 28 anchor piles are added on the right side wall of the section K1+330-K1+360 of the 4# diversion tunnel, the interval row distance is 2.5 multiplied by 2.5m, and the length is 18m. Wherein 815.5m is 2 rows above elevation and 811.0m is 3 rows below elevation;
(9) For the positive collapse area on the right side of the 3# diversion tunnel 1+190-1+270m, adding a self-advancing anchor rod, burying a phi 20PE pipe in the self-advancing anchor rod as a grouting pipe, installing a grout stop plug and a backing plate at the position close to a rock face, and performing simple consolidation grouting on the rock body by using the self-advancing anchor rod to pour pure cement slurry, wherein the parameters of the self-advancing anchor rod are as follows: Φ38, l=12m, with an inter-row spacing of 1m×1m;
(10) The concrete sprayed below the arch angle of the right side wall of the 3# diversion tunnel 1+160-1+180 m and the left side wall of the 4# backflow tunnel 1+310-1+450 is adjusted to be wet spraying by a dry spraying method, and the bottom backfilling stone slag is adopted as a construction platform, and the slag filling height is about 3-4 m.
(11) And a row of downward inclined anchor piles are respectively added at the top of the non-excavated rock platform (about 10.6m high) of the section 1+285-1+310 of the 4# diversion tunnel, so as to anchor the non-excavated rock mass. The anchor pile parameters 3 phi 28 and L=12m, the spacing is 2m, and the inclination is 30 degrees.
(12) 3 rows of anchor pile are added to the right side wall of the 4# diversion tunnel 1+311-1+330, and parameters of the anchor pile are as follows: 3 Φ28, l=18m, pitch 2.5m.
(14) 6 rows of 18m long anchor piles are added to the left side wall of the 3# diversion tunnel 1+389-1+472 m, and the interval row spacing is 2.5X2.5 m.
(15) And 2 multi-point displacement meters are added to the left side wall part at the pile numbers of K1+290 and K1+320 of the 4# diversion tunnel, the measuring range is 25m, and the deep monitoring of the collapse body is enhanced.
(16) In order to strengthen the rock mass, the anchor bar pile and the anchor rope are arranged on the position, and the anchor bar pile hole and the anchor rope hole are used as consolidation grouting holes to carry out simple consolidation grouting on the surrounding rock. The consolidation grouting pressure is 0.3-0.5 MPa, thick slurry is firstly adopted for grouting, and the water-cement ratio of the slurry is 0.35-0.5:1.
(17) And after the slag body in the collapse area is excavated and the self-advancing anchor rod construction is completed, carrying out concrete backfill on the collapse body, and carrying out backfill twice in total. Backfilling the inside of the collapse body at 803.7 elevation for the first time, wherein the maximum depth is about 9.5m, backfilling the collapse body layer by layer from bottom to top, wherein the backfilling height of each layer is 3-3.5 m, and pumping the collapse body into a bin by adopting a C25 secondary concrete pump; and backfilling the residual 3m thick concrete of the collapse body and the side top arch lining concrete (1.2 m) by adopting a steel mould trolley for the second time, wherein the mark of the backfilled concrete for the second time is C9030 with the mark of the side top arch lining concrete. And arranging a row of opposite-penetrating anchor cables at the EL808 elevation of the area 1+400-1+450 m of the 4# diversion tunnel, wherein the distance between the anchor cables is 4m, leading the end parts of the anchor cables to the surface of the concrete lining by adopting pre-buried phi 150 steel pipes, and tensioning after the concrete lining is completed.
In order to strengthen the connection force between the backfill concrete and the rock mass, the inside of the backfill concrete is provided with corner ribs, the corner ribs are welded with rock face system anchor rods, every other system anchor rod is provided with one corner rib, the specification is phi 25, L=1.5m (wherein the corner length is 30cm, the straight line length is 120 cm), and the interval is 2×2m.
Because the backfill concrete is constructed twice, connecting dowel bars are arranged on the concrete construction joint surface, the dowel bar specification is phi 25, L=3.0m, and the interval is 1.5x1.5m; the exposed part is 1m, and the embedded concrete is 2m. The exposed dowel bars and the later-stage side roof arch lining steel bars are effectively connected by adopting phi 25 steel bars to form a whole.
Thirdly, establishing an integral supporting arch stress body formed by steel arch frame-mould spraying concrete-secondary backfilling;
1) According to the structural characteristics of the diversion tunnel cross section cavity, the middle layer of the diversion tunnel is excavated in a thin layer excavation mode from top to bottom, and the two rear sides are excavated in an expanding excavation mode; and timely sealing surrounding rocks and the face around the excavated area;
according to the structural characteristics of the oversized-section cavity, a thin layer excavation method from top to bottom is adopted. The large-section cavity is preferably divided into 4-5 layers, the height of the upper layer is 9.0-10 m, and the construction is strictly performed according to a cycle program of each cycle of excavation supporting in site by adopting an excavation method of expanding and excavating the two sides to follow up or full-section feeding ruler after the advanced exploration and the supporting of the middle pilot tunnel are finished. The middle lower layer adopts an excavation method of a middle pull groove and two reserved protective layers at the two sides, and the layering heights are 4-6 m. The rock mass is reinforced in time by adopting a thin layer excavation and one cycle and one support method, so that disturbance and deformation of blasting on the rock with a large section are reduced, and the generation of large collapse is effectively prevented.
After excavation, a layer of 5-8 cm steel fiber concrete is sprayed on surrounding rocks and the tunnel face in time to seal, secondary damage to the surrounding rocks caused by weathering is avoided, an initial simple flexible supporting ring is formed, so that the self-stabilization time of the surrounding rocks is prolonged, and the tunnel face is kept approximately perpendicular to the hole axis by using plain concrete sealing measures of the tunnel face, so that large-scale mechanical operation is facilitated, and the follow-up safe supporting progress is accelerated.
2) Carrying out anchor bolt support on the closed surrounding rock, and carrying out steel arch installation, steel bar net hanging and disassembly-free template installation;
and a certain number of system anchor rods are timely arranged after concrete is sprayed, so that the suspension effect of the system anchor rods is exerted as soon as possible, and the stability of surrounding rock is further enhanced.
The system anchor rod is preferably provided with a multi-arm drill (compared with a manual hand drill which is only suitable for construction on II and III type surrounding rocks, the multi-arm drill has stronger adaptability in IV and V type surrounding rocks and broken weak weathering surrounding rocks, and realizes faster, high-quality and safe construction), and the system anchor rod is inserted in time after hole forming, so that hole collapse caused by long-time laying is avoided. The self-advancing anchor rod is adopted at the position where the hole cannot be formed. The system anchor rod hole site lofting should consider the steel supporting position, is convenient for weld the extension with the stock and consolidate the steel support.
After the primary spraying is finished, the steel arch is installed by the cooperation of the drilling and blasting trolley and the manual work. The steel arch frame generally adopts I20I-steel, and the truss spacing is between 0.75 and 1 m. Each steel arch frame is allowed to be used on site after being accepted in a factory. And the steel arch is measured and lofted before being installed, so that the installation position of the steel arch is ensured to meet the design requirement. During installation, the backing plate bolting, welding of the arch frame and the connecting channel steel, injection of the locking foot anchor rods, welding quality of the system anchor rods and the steel arch frame and the like are mainly controlled, the next working procedure is allowed after each working procedure experience is qualified, and the installation quality of the steel arch frame is required to meet the design and specification requirements.
The steel support is arranged outside the section of the lining design, enough concrete spraying thickness is reserved, and the later concrete spraying cannot encroach on the section of the lining. Because of the ledge structure after the thin layer rock mass is excavated, the peeling is serious along the layer, so that the gap between the steel arch frame and the rock surface is larger, and an auxiliary arch is additionally arranged between the steel arch frame and the rock surface of the cavity for effectively forming a supporting arch. Channel steel is added between the steel support truss frames to form a steel truss structure so as to increase rigidity of the disassembling-free formwork between the steel support truss frames.
And a double-layer reinforcing mesh is hung on the side of the steel support close to the rock face, a disassembly-free quick-easy-closing-in template is mounted, the reinforcing mesh and the disassembly-free template mesh are required to be tightly connected with a system anchor rod and the steel support in a welding mode and the like, and the disassembly-free template is prevented from being damaged when the concrete is sprayed.
3) And performing mould spraying concrete between the installed steel arch and the surrounding rock face, and filling gaps by adopting secondary backfilling grouting or pumping concrete, so that the steel arch, the mould spraying concrete and the backfilling concrete form an integral supporting arch stress body. For the parts with the cavity area larger than 1m, pumping concrete is adopted to fill the gaps, and for the parts with the cavity area smaller than 1m, backfilling grouting is adopted to fill the gaps.
Fourthly, performing layered blasting excavation treatment on the rock plug section of the main tail water hole intersected with the diversion tunnel;
as shown in FIG. 5, the main 5# tail water holes and the main 6# tail water holes which are intersected with the 3# diversion tunnel and the 4# diversion tunnel in a small included angle are formed by the step of carrying out layered excavation on the main 5# tail water holes and the main 6# tail water holes, wherein the rock plugs in the middle of the intersection are 3# and the middle partition wall collapse areas of the 4# diversion tunnel, the main 5# tail water holes and the main 4# tail water holes belong to IV type surrounding rocks, the main 5# tail water holes are divided into four layers of excavation, the I layer layering height is 9.85m, and the I layer layering height of an H (K) type standard section is 9.35m; the excavation heights of the II layer and the III layer are 6.0m; the layering height of the lower layer bottom plate of the IV layer is 4.5 m-6.0 m.
Layer I blasting design, design parameters are shown in table 1 below.
Table 1 table I layer drilling and blasting construction technique parameter table
And the layers II and III are all horizontal holes drilled by YT-28 hand wind drill, the drilling diameter is phi 42mm, the drilling depth is 4m in each cycle, and the drilling length is about 3.5m in each cycle. The row spacing between the horizontal main blastholes is 1.2m multiplied by 1.0m. The main explosion hole adopts phi 32mm emulsion explosive to continuously charge, the blocking length of the orifice is 1m, and the single-hole explosive amount is 2.8-3.0 kg. The maximum single-dose dosage is controlled within 50 kg. Layer II and layer III blasting designs, and design parameters are shown in Table 2 below.
Table 2 table II layer III layer drilling and blasting construction technique parameter table
And IV layer excavation is started after III layer excavation is completed, and construction is performed by adopting a full-section excavation mode. The lower layer excavation adopts YT-28 hand pneumatic drill and the drilling and blasting trolley to drill horizontal holes for excavation, and the design contour line adopts smooth blasting. The hole depth was 4m per cycle and the length was about 3.5m per cycle. Layer IV (lower layer) excavated blast design, design parameters are as follows table 3.
Table 3 table IV layer drilling and blasting construction technique parameter table
In order to ensure the excavation forming quality of the high side wall of the large underground cavity and reduce the influence of blasting vibration on rock mass, the shallow Kong Lacao of the middle 6-7 m bench is adopted comprehensively, 4-5 m protection layers are reserved on two sides, and the protection layers are subjected to vertical light blasting follow-up excavation, so that the principle of 'thin layer excavation and layer supporting' is strictly adopted. In the excavation scheme, a movable standard sample frame technology is specially adopted for fully erecting vertical photo-explosion holes to control the excavation forming quality, a hand air drill is adopted to drill small holes, the vertical photo-explosion is carried out, the single-sound explosive quantity is controlled within 10kg, and meanwhile, a strict and refined blasting control technology is adopted for a protective layer to reduce the blasting vibration influence.
And fifthly, establishing a safety detection early warning system to monitor surrounding rocks of the poor geological disaster area of the diversion tunnel in time so as to guide site construction.
In order to know and master deformation and stress strain conditions of surrounding rock in time, engineering geology, hydrogeology data, design files and actual conditions of on-site excavation engineering are disclosed in combination with the on-site, and temporary safety monitoring and permanent safety monitoring work in the construction period are actively carried out. And (3) carrying out encryption observation on the displacement mutation and the parts with larger change in the monitoring process according to one monitoring section every 30-50 m on poor geological areas such as surrounding rock areas of diversion holes III-V, areas with richer underground water, fault fracture zones, tunnel and fork areas, areas with shallower burial depth, areas with larger influence by adjacent area excavation and high ground stress areas. And a multipoint displacement meter, an anchor rod stress meter and other permanent monitoring instruments are arranged at the key position. And the deformation condition of surrounding rock is known and mastered in time, and the on-site construction is fed back and guided in time. Meanwhile, a dynamic design construction technology combining numerical calculation and construction process is adopted, construction parameters are determined, optimized and adjusted in time through calculation and analysis, construction is guided, and the correctness of a construction method is verified. The construction period safety can be effectively solved, and the construction progress is ensured.
The construction method is successfully applied to the guide hole 3# and 4# on the right bank of the Wu Dongde hydropower station, and good effects are obtained. Along with the development of national economy, the excavation of underground caves under complex geological conditions is increased continuously, and particularly, the continuous start of national key projects such as Western gas and east transmission, western electric east transmission and the like in recent years is realized, a great number of project problems with high difficulty under complex geological conditions are caused, collapse problems are serious, and the traditional geological exploration and experimental methods often cannot comprehensively provide the technology required for solving the geological conditions. The project relies on the research of the large-scale collapse engineering case of the diversion tunnel group mid-partition wall of the Wu Dongde hydropower station to summarize and refine the construction method and the technical means. Can provide reference for other similar projects and has wide popularization and application prospect.
According to the method for constructing the poor geological disaster of the diversion tunnel, according to the complex geological condition of the site, the collapse area adopts a 'fast sealing, composite arch supporting stress body reinforcing support, deep layer support and shallow layer support in parallel', surrounding rocks at the upper and lower sides of the collapse area are stabilized firstly, and collapse area treatment is carried out after the stress of the collapse area is stabilized; the later excavation adopts a mode of plugging firstly and excavating later to stabilize the rock mass with a small included angle, the side wall adopts a mode of thin layer excavation, supporting along with the layer, vertical light explosion and fine explosion control, a safety monitoring early warning system is established, the safety and stability of a large-scale collapse area of the intermediate wall of the diversion tunnel with an extra large section are ensured through the control measures of safety monitoring guiding excavation and the like, and the technical problem of collapse treatment construction of the intermediate wall of the diversion tunnel, particularly the intermediate wall of an extra large tunnel chamber is effectively solved. The potential safety hazard and treatment cost of the large collapse are avoided, the indirect economic benefit and the social benefit are huge, and the construction process, the construction quality and the construction benefit are consistently confirmed by a traditional quality expert group.
Although embodiments of the present invention have been disclosed above, it is not limited to the details and embodiments shown, it is well suited to various fields of use for which the invention is suited, and further modifications may be readily made by one skilled in the art, and the invention is therefore not to be limited to the particular details and examples shown and described herein, without departing from the general concepts defined by the claims and the equivalents thereof.
Claims (9)
1. The method for constructing the poor geological disaster of the diversion tunnel is characterized by comprising the following steps of:
step one, stabilizing surrounding rocks at the upstream and downstream of a bad geological disaster area: performing supporting construction on upstream and downstream surrounding rocks in an undesirable geological disaster area;
step two, construction treatment of a poor geological disaster area: sealing the poor geological disaster area, and supporting the stressed body by the composite arch to strengthen the support, the deep support and the shallow support;
thirdly, establishing an integral supporting arch stress body formed by steel arch frame-mould spraying concrete-secondary backfilling;
fourthly, performing layered blasting excavation treatment on the rock plug section of the main tail water hole intersected with the diversion tunnel;
and fifthly, establishing a safety detection early warning system to monitor surrounding rocks of the poor geological disaster area of the diversion tunnel in time so as to guide site construction.
2. The method for constructing a poor geological disaster of a diversion tunnel according to claim 1, wherein the first step specifically comprises: the guide hole middle partition wall is provided with a plurality of rows of anchor ropes which are penetrated in pairs, the left side wall is provided with a plurality of rows of anchor bar piles, and the right side wall is provided with a plurality of rows of anchor bar piles.
3. The method for constructing a poor geological disaster of a diversion tunnel according to claim 1, wherein the second step comprises the following steps:
s1, sealing: c25 coarse fiber concrete with the thickness of 15cm is sprayed on the cracking part system of the concrete spraying layer of the upstream side wall and the downstream side wall of the poor geological disaster area for primary sealing; arranging a hole outside slag pulling foot protector on a side wall of a poor geological disaster area, and adding a reinforced gabion on a side of a channel of the poor geological disaster area to protect slag piling feet;
s2, reinforcing and supporting the composite arch supporting stress body: supporting the diversion tunnel by using a supporting steel, and simultaneously performing system concrete spraying treatment;
s3, deep layer support and shallow layer support: and (3) carrying out reinforced supporting treatment of combining the anchor bar piles with the anchor cable deep and shallow layers on the poor geological disaster section, and simultaneously carrying out systematic consolidation grouting construction on the whole side slope by adopting the anchor bar piles and the anchor cable holes.
4. A method for constructing a poor geological disaster of a diversion tunnel according to claim 3, wherein the third step comprises the following steps:
1) According to the structural characteristics of the diversion tunnel cross section cavity, the middle layer of the diversion tunnel is excavated in a thin layer excavation mode from top to bottom, and the two rear sides are excavated in an expanding excavation mode; and timely sealing surrounding rocks and the face around the excavated area;
2) Carrying out anchor bolt support on the closed surrounding rock, and carrying out steel arch installation, steel bar net hanging and disassembly-free template installation;
3) And performing mould spraying concrete between the installed steel arch and the surrounding rock face, and filling gaps by adopting secondary backfilling grouting or pumping concrete, so that the steel arch, the mould spraying concrete and the backfilling concrete form an integral supporting arch stress body.
5. The method for constructing the poor geological disaster of the diversion tunnel according to claim 2, wherein the anchor cables are arranged in 4 rows, and the interval is 4 x 4m; the anchor piles arranged on the left side wall and the right side wall are all 6 rows, and the interval row spacing is 2.5 multiplied by 2.5m.
6. A method for constructing a poor geological disaster of a diversion tunnel according to claim 3, wherein the size of the reinforced gabion is 3×1×1m, the row spacing between the reinforced gabions is 20cm×20cm, the diameter of the main reinforcement is 22mm, and the diameter of the web reinforcement is 14mm.
7. The method for constructing a poor geological disaster of a diversion tunnel according to claim 3, wherein the supporting the steel support in the diversion tunnel in the step S2 specifically comprises: the diversion tunnel side wall is provided with I20b I-steel which is welded with anchor rods arranged in the side wall, the I-steel is longitudinally provided with connecting channel steel, and the circumferential spacing is 1.5m.
8. The method for constructing a poor geological disaster of a diversion tunnel according to claim 4, wherein in the step 1), the timely sealing of surrounding rocks and face around the excavated area comprises: and spraying a layer of 5-8 cm steel fiber concrete on the surrounding rock and the face to seal.
9. The method for constructing a poor geological disaster of a diversion tunnel according to claim 1, wherein the fourth step comprises the following steps: the middle 6-7 m bench shallow Kong Lacao is adopted, 4-5 m protection layers are reserved on two sides, vertical light explosion follow-up excavation is adopted for the protection layers, movable standard sample frames are all erected on vertical light explosion holes, hand air drill drilling is carried out, vertical light explosion is carried out, and the single-shot dosage is controlled within 10 kg.
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| CN117552813B (en) * | 2024-01-12 | 2024-03-15 | 中国矿业大学(北京) | Surrounding rock reinforcement construction method for deep roadway |
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