A kind of method of mud-rock flow stratum tunnel excavation
The present invention relates to Tunnel Engineering field more particularly to a kind of methods of mud-rock flow stratum tunnel excavation.
Mud-rock flow is a kind of temporary mighty torrent containing a large amount of silt particles and stone occurred in mountain area.Mud-rock flow and general flood
The main distinction of stream is that this fluid is made of solid and liquid, and solid matter content is larger, solid under special circumstances
Body ingredient accounts for 80% or more, and severe is up to 23kN/m3.Its feature is: outburst suddenly, energy is huge, lasts of short duration, recurrence
Frequently.Therefore, destructive power is huge.Slope surface landform is the main source of mud-rock flow solid matter, and the overwhelming majority is natural solid object
Source, solid material resource constitutes Clastic Stratum of Country Rocks exposed in predominantly region, the fragmentary soil covered on hillside, and is deposited in slope surface
Upper saprolite of varying thickness.Due to as long as the heaven and earth endure, four seasons weathering, clastic rock is presented soft and hard alternation mostly, rock mass also different journeys
Degree ground loosens removing, generates a large amount of rubble sillars, is unevenly covered on basement rock, encounters larger rainwater and come, easily quilt cover
Stream is washed away to be taken away with large area.Close to the deposit of side slope bold shore, erosion is washed in a pan by flood, easily formation avalanche increases mudstone again
The solid material resource of stream constitutes the main belongings of mud-rock flow.
Tunnel passes through mud-rock flow stratum, and the data that the special construction technology of maturation is reported in media both at home and abroad at present is less, and one
As be all to work out measures according to the specific geological characteristics of engineering and improved and supplemented again by groping, finds rule, formation phase
Engineering construction is used for perfect operational procedure, but construction speed to be slow, it is careless slightly to occur as soon as landslide phenomenon, such as Lan Yu Railway
The report of flax ridge construction of tunnel, difficulty of construction shocks common people, but its construction technology is asked mainly for special individually
Topic, and it is used to instruct the construction also impassable limitation of generality, such as advanced precipitation or grout curtain and this project institute
The stratum at place is not inconsistent, and construction reference is little.
Mud-rock flow slip mass stratum cavitation there are the problem of and risk:
1. in mud-rock flow stratum tunnel excavation, what is initially encountered is that moisture storage capacity is very big in stratum, in digging process, once it is right
Water flow in stratum cannot be appropriate control, the flowing of water will carry silt particle and gushes out from work surface, in turn result in slip mass
Stone is aerial, loosens, and the slump and movement of stone form very big impact energy, destroys the bracing members of cavern excavation installation.
2. being destroyed to structure and almost being completed in moment, without bracing members reparation from sedimentation, deformation by the bracing members impacted
Breathing spell and time.
3. the balance of mud-rock flow earth formation is once broken, it is equivalent to the bottleneck for opening Pan Gela spell, if made
Industry face water gushes out the prominent mud of initiation, gushes mud (sand) phenomenon, and the slip mass stone, erratic boulder, boulder after making somebody a mere figurehead will generate sliding, collapse
It falls, not only the existing support system of impact failure, but also the pressure of tunnel branch support is increased, the appearance of landslide just institute again
Inevitably, it is difficult to tidy up.
4. when the tunnel excavation of mud-rock flow stratum, the excavation working depth in chapelet face will be controlled suitably, once in chapelet face one
Secondary excavation height is excessive to cause chapelet face unstability, thus mud-rock flow generates, and not only mud-rock flow swallows up tunnel, work surface is forced back several
Rice, ten meters or tens of rice, and the completed steel shotcrete support system in front will be seriously damaged, and fight for " commanding elevation " again
Fight will be unfolded again, need the mud-rock flow cleared up in tunnel again, the bracing members removing deformation or destroying, the steel more renewed
Support, reaches new balance and stabilization.
5. slip mass earth formation is complicated, the existing block different greater than the boulder and slumping block partial size of hole diameter in stratum
Stone, also covered soil, sand are mixed with together, and content distribution is different, poor using well cementing mode preconsolidation effect,
Difficulty is big.
6. daguanpeng construction is restricted by formation condition and cavern's section, can not be unfolded.
Summary of the invention
It is an object of the invention to overcome the problems, such as existing mud-rock flow tunnel excavate present in above-mentioned risk and, one kind is provided
The method of mud-rock flow stratum tunnel excavation in the existing balance for not breaking mud-rock flow, makes mudstone other than tunnel excavation range
In the case that fluid is not disturbed or disturbed less, reinforcing bar frame and separation layer pair are completed with second underpinning technology using once underpining
The support for excavating the outer mud-rock flow of range, to move forward steadily the excavation of mud-rock flow stratum tunnel.
To achieve the goals above, the present invention adopts the following technical scheme that: a kind of side of mud-rock flow stratum tunnel excavation
Method, this method comprises: first the hole segment frame outside debris flow body sets 3-5 Pin arch bracing members, to close on the bracing members of debris flow body
As starting point, the reinforcing bar equidistantly arranged is inserted into debris flow body at the top of bracing members, reinforcing bar gos deep into mud-rock flow stratum, each
With bracing members firm welding, the upper end arcuate part of arch bracing members is provided with reinforcing bar, forms arch for the tail portion of root reinforcing bar
Reinforcing bar frame；The gap of reinforcing bar frame is connected using seepy material with reinforcing bar frame, and one of permeable impermeable mud is formed
Separation layer；When tunnel excavation, once discovery debris flow body, step-like as bearing pointdisposal by the bracing members for closing on debris flow body
Partition forms the space of different height by debris flow body barrier at stepped form, according to different spatial altitudes, first close
The bracing members two sides of debris flow body are respectively arranged outrigger, and the arch bracing members of overhanging are equidistantly set up on outrigger, arrange reinforcing bar
Frame and separation layer first install bracing members, then as long as space more than mud-rock flow surface layer is able to satisfy the installation of arch bracing members
Reinforcement placing frame and separation layer.
The reinforcing bar equidistantly arranged is used being close at the top of the mounted arch bracing members of face within the scope of entire arch
Reinforcing bar shed frame method is squeezed into, and reinforcing bar length is not less than 3.5m, is formed the reinforcing bar frame that spacing is 10 ~ 30cm, is goed deep into mud-rock flow stratum
The erection method of bracing members: 1 Pin arch bracing members is first set up, layer 2-3 baffle is arranged vertically in face, to hole
Mud-rock flow is controlled at the face of room, gradually scarfing cinder, is allowed to have the space for installing next Pin vault bracing members, two adjacent
Arch bracing members between spacing be no more than 0.5 meter.
In the side wall direction of bracing members, multiple rows of dowel is arranged, and bracing members firm welding, to facilitate on the outside of bracing members
Concrete back plate or the lumps of wood are installed and close side wall, backfill it is closely knit, prevent mud-rock flow flowed sideways by bracing members excavated it is molding
3 Pin arch bracing members are at least installed on every outrigger.
For prevent arch bracing members set up after, because top load greatly caused by bracing members integral sinking, arrangement bracing members or
When reinforcing bar frame, 10 ~ 20cm of settling amount is preset, i.e., hole top is digged and is higher by 10 ~ 20cm of design section.
Cross-brace is welded in the two sides bottom end at every Pin bracing members arch position, fulcrum is located on the outrigger of overhanging, In
1-2 root fashioned iron column is arranged in the axial location at the bracing members arch position of overhanging, and column lower part is supported with precast concrete pedestal.
After the completion of shield top work, by gradually scarfing cinder in the extroversion hole of hole, the hole section that first will be far from mud-rock flow is excavated to tunnel bottom
Plate elevation installs concrete prefabricated cushion block by bracing members lower leg portion spreading, and in bottom plate, is located in bracing members supporting leg
On concrete prefabricated cushion block, the complete bracing members of a ring are formed, remove fashioned iron column.
The good effect that technical solution of the present invention generates is as follows: the method for mudstone laminar sublayer tunnel excavation of the invention,
The relative stability having using mud-rock flow itself completes reinforcing bar frame and separation layer to excavation range using a underpinning technique
The support of outer mud-rock flow does not break the existing balance of mud-rock flow, disturbs the debris flow body other than tunnel excavation range not
Or few disturbance；The separation layer of permeable impermeable (mud) sand is formed, one is easy for the draining of debris flow body, prevents ponding from causing mudstone sliding
It is dynamic, second is that preventing silt particle in debris flow body to be lost making somebody a mere figurehead between forming stone, to cause boulder and erratic boulder sliding generation impact
Power destroys canopy protection structure.Second underpinning technology mainly for bracing members, by shore plus the temporary structure of overhanging be converted to closing at
The good whole force structure of ring stress.
Under the premise of keeping mud-rock flow metastable, it is isolated excavating in range with the debris flow body of reservation.Make to excavate
When mud-rock flow in range is removed, the carrying contact surface of top mud-rock flow is undertaken by the slider underpined, and slider is able to satisfy
The bearing requirements of the debris flow body of reservation, and reach draining it is unimpeded, avoid the formation of ponding cause debris flow.By reinforcing bar frame
Tail end weld together with bracing members, and with go deep into mud-rock flow reinforcing bar frame front end formed simple beam structure, by hole with
The mud-rock flow on hole top separates, and completes reinforcing bar frame, bracing members system and underpins work to what the above mud-rock flow stratum was pushed up in hole.Top arch
Rigid frame is taken at position, and side wall is declined using precast concrete block gear shield with excavation height, convenient installation in time.To ensure
Cantilevered structure safety, it is desirable that every outrigger must connect the complete bracing members of three Pin or more, i.e. formation " three choose one " pattern.It formulates
Mud-rock flow propping of subterranean formations, support system conversion once underpin, second underpinning operating technology measure, it is ensured that mud is not disturbed in construction
Rock glacier has certain self-stable ability and supporting system using the internal friction and movement angle of repose of mud-rock flow stratum internal structure
Common stress keeps the relatively stable of mud-rock flow and balance.
Detailed description of the invention
Fig. 1 is the primary side structure schematic diagram underpined with the reinforcing bar frame of second underpinning of the present invention.
Fig. 2 is the structural schematic diagram of arch bracing members of the present invention.
Fig. 3 is the arch bracing members schematic diagram that the present invention overhangs.
It is marked in figure are as follows: 1, arcuate part；2, supporting leg；3, reinforcing bar；4, separation layer；5, backboard；6, dowel；7, it laterally props up
Support；8, outrigger；9, baffle；10, concrete prefabricated cushion block；11, bottom plate；12, fashioned iron column；13, connecting plate；14, concrete
Native pedestal；15, mudstone flowing liquid coboundary；16, mudstone flowing liquid lower boundary.
Combined with specific embodiments below and attached drawing makees the technical solution of the method for mud-rock flow stratum of the present invention tunnel excavation
Further elucidated above and explanation.
Embodiment one: the power station Nepal Yi Lamu diversion tunnel case
Nepal's Yi Lamu diversion and power station diversion tunnel is about 3500m, tunnel excavation section 2.5m*2.5m, and tunnel is
Gateway opening shape, tunnel outlet hole section, which need to pass through, is about 400m slip mass；A branch hole need to pass through the slip mass of nearly 200m.This area
Lower water level is high, and during tunnel excavation, slip mass is because rich water, stratum are unstable, after the completion of supporting, because of water burst, gushes mud (sand) and draws
Hair outwash activity causes tunnel repeatedly to cave in.After tunnel outlet hole section is excavated and completes bracing members strong supporting about 100m, chapelet
There is linear discharge orifice and closes not in time in face, causes mud-rock flow and swallows up 100m tunnel, and cause roof fall, ground forms length and width about
The hole of collapsing of 20*40m.Water diversion tunnel project is passing through intensive landslide stratum and crack, fault belt and coombe position
When, size occurs and caves in more than 100 times, more than 30000 side of landslide total amount, the close newly-increased same size tunnel of landslide total amount is (i.e.
It is equivalent to the excavated volume for completing two design tunnels).
The tunnel excavation is carried out with second underpinning technology using of the invention once underpining, the specific steps are as follows:
1. first the hole segment frame outside debris flow body sets 3-5 Pin arch bracing members, arch bracing members include the arch portion on top
Point 1 and lower part supporting leg 2, spacing is 0.5m between adjacent bracing members, to close on the bracing members of debris flow body as starting point, along steel
32 reinforcing bar 3 of Φ that length is not less than 3.5m is squeezed into using reinforcing bar shed frame method into debris flow body in branch support, on entire bracing members
The arcuate part in portion is inserted into reinforcing bar, forms the reinforcing bar frame that bar spacing is 20cm, and permeable using geotextiles etc. to ceiling
Material carries out the separation layer 4 that closing forms permeable impermeable mud (sand), reaches not and occurs gushing mud, gushes sand phenomenon；By controlling frame
Mud (sand) does not generate flowing in the mudstone flow structure of top, reach control mud-rock flow stratum inside do not generate aerial phenomenon, avoid because
Aerial phenomenon is generated, causes the boulder in mud-rock flow stratum, block stone slides and movement forms impact force；By the tail end of reinforcing bar frame
Weld together with bracing members, and form simple beam structure with the reinforcing bar frame front end for going deep into mud-rock flow, by what is pushed up in hole with hole
Mud-rock flow separates, and completes reinforcing bar frame, bracing members system pushes up the primary of the above mud-rock flow stratum to hole and underpins work；
The method for setting up arch bracing members is as follows: 1 Pin (hole 1/2-1/4 is high) arch bracing members are first set up, it is perpendicular in face
Straight arrangement layer 2-3 baffle, controls mud-rock flow at cavern's face, forms mudstone flowing liquid coboundary 15 and mudstone flow liquid
Body coboundary 16, gradually scarfing cinder are allowed to have the space for installing next Pin bracing members arcuate part, two adjacent arch steel branch
Spacing between support is 0.5 meter；During scarfing cinder, observation hole top reinforcing bar frame and bracing members stress condition, bracing members arch
Position can a step be installed in place, also visual vault support upper pressure situation and space size, are installed in place in two times, that is, complete
The installation of the whole or half height at bracing members arch position.
The production at bracing members arch position forms in processing factory in such a way that broken line is at arc, generally presses axial length 50-
60cm or so is a broken line, this engineering is made of 16 I-steel, takes 16 I-steel length=2.5*3.14m blanking, make to make
The outer arc length of the bracing members of work is equal with the arc length of cavern excavation section, presses that (2.5m*3.14/0.56m=14 break is by I-shaped
Steel work done in the manner of a certain author is that the one side of inner arc is cut with gas welding, and notch is cut into " V ", and it is 3.14* that each " V " shape notch, which cuts off width suitable for reading,
0.16/14=3.5-3.6cm, then the notch manual adjustment of I-steel, which is healed up, to be put into the mold that bracing members make fixes,
Again the gap firm welding of notch is completed by the bending production of a Pin bracing members segmental arc using electric welding mode.For convenience
Segmental arc bracing members are disconnected at middle part, then connecting plate 13 are respectively welded by the installation of bracing members segmental arc at the scene, are divided into two parts
Whole arch is linked to be using bolt after installation.
2. arrange multiple rows of dowel 6 in the side wall direction of bracing members, and bracing members firm welding, to facilitate in bracing members
Concrete back plate 5 is installed in outside, and backfill is closely knit, is prevented mud-rock flow from being flowed sideways by bracing members and has been excavated in molding tunnel.
3. when tunnel excavation, once discovery debris flow body, keeps off by the bracing members for closing on debris flow body as bearing pointdisposal
Plate 9 forms the space of different height by debris flow body barrier at stepped form, according to different spatial altitudes, first close to mud
The bracing members two sides of rock glacier body are respectively arranged outrigger 8, and outrigger is welded on the supporting leg of bracing members, equidistantly set up on outrigger outstanding
The arcuate part for the arch bracing members chosen, and by the bracing members firm welding of outrigger and overhanging forms and attacks and occupies the of mudstone stratum
One layer of shield pushes up cantilevered structure, and outrigger is i-beam structure；To ensure cantilevered structure safety, it is desirable that every outrigger must connect three Pin
The above complete bracing members, i.e. formation " three choose one " pattern form reinforcing bar scaffolding structure, steel then by the requirement of step 1 again
Muscle frame tail end and the bracing members of overhanging weld together, and form second reinforcing bar frame simply supported beam and underpin system.
4. cross-brace 7 is welded in the two sides bottom end at every Pin bracing members arch position, fulcrum is located at the outrigger of overhanging
On, in the axial location of the arch bracing members of overhanging, 1-2 root fashioned iron column 12, column lower part precast concrete pedestal 14 are set
5. repeating 3 and 4 steps, the arch bracing members of installation the 2nd Pin overhanging complete the second layer and attack and occupy mud-rock flow stratum
Shield top cantilevered structure；As long as space more than mud-rock flow surface layer is able to satisfy the installation of arch bracing members, i.e., bracing members to be installed, so
Reinforcement shed frame and separation layer are set up afterwards.
6. after the completion of above-mentioned work, by gradually scarfing cinder in the extroversion hole of hole, the hole section that first will be far from mud-rock flow is excavated to tunnel
After floor elevation, concrete prefabricated cushion block 10 is installed by the lower leg portion spreading of arch bracing members, and in bottom plate 11, makes steel
Support leg is located on concrete prefabricated cushion block, forms the complete bracing members of a ring, removes fashioned iron column.
7. gradually removing supporting section mud-rock flow slag charge, Vault Steel Construction of Supporting is pushed ahead on one side, completes steel branch on one side
The supporting leg installation (1-2 step is divided to complete) of support, is followed by this ring and gradually pushes ahead operation；In work progress, strict control mud-rock flow
Slope angle in hole is stablized, and it is bottomed to floor elevation gradually to remove hole slag；Precast concrete is used immediately to the side of bracing members
Block filling, completes complete steel shotcrete support system.Excavation is moved forward steadily according to above-mentioned operational procedure, up through debris flow body
Under normal circumstances, it is unfolded to construct generally according to above-mentioned 7 steps, when such as inserting piling reinforcing bar, encounters boulder and erratic boulder is invaded
Excavated section is accounted for, needs to take control slagging measure, slides boulder and erratic boulder to hole, unless the boulder volume is big, completely
Cavern excavation section is blocked, before vault bracing members are installed, it is small to carry out Blow-Up Solutions；Generally it is less than excavated section in boulder volume
When, before not influencing bracing members integral installation, as far as possible after bracing members form entirety, then carry out blowing out the small removing of solution.Under boulder
During dropping down onto excavated section, using necessary assistance is manually carried out, guarantee that lonely, erratic boulder does not influence installing for bracing members.
After preventing bracing members from setting up, because top load greatly caused by bracing members integral sinking, in arrangement bracing members or reinforcing bar
When frame, settling amount 20cm is preset, i.e., hole top is digged and is higher by design section 20cm.
It takes and has once underpined with second underpinning, since the construction technology that does not disturb (few disturbance) mud-rock flow, it is subsequent in mudstone
Only occurs very small-scale landslide twice during stream stratum tunnel excavation, it is logical that the sump remedy time is no more than 15 days i.e. safety
It crosses, mud-rock flow stratum tunnel excavation can keep 15m/ drill footage per month to stablize promoting, and highest drill footage per month reaches 25m/ month, her drawing of Nepal
Nurse diversion and power station engineering obtains Nepal king gold medal.
Embodiment one phase of two: 8.2 Middle Line Project For Transferring Water From South To North Engineering Through the Yellow River case
One phase of Middle Line Project For Transferring Water From South To North Engineering Through the Yellow River water-break building, which is located at, wears yellow tunnel downstream, main shaft and wears yellow tunnel axis
It 9.9947 ° of the line angle of cut, is made of inducer, water-break hole, the outlet buildings such as stilling pond and drain tank, axial length
1019.21m.Water-break building by water-break pierces more Mangshan Mountain and will wear yellow tunnel import to be connected to the Yellow River, and main function is to wear
During yellow tunnel for overhaul, the extra water of general main canal is discharged into the Yellow River；It has concurrently in succession to the Yellow River moisturizing effects simultaneously.
Water-break hole overall length 790m, import floor elevation 110.5m export floor elevation 94.0m, longitudinal slope 2.09%.Tunnel
Section is the gateway opening type with inverted arch, cross dimensions 4.20m*5.80m(wide * high after lining cutting), excavated section 5.80m*7.50m
(wide * high).Wherein Portal Section is transition, long 20m, concrete lining thickness 80cm；Standard barrel section abutment wall and crown coagulation
Native lining thickness 50cm, underplate concrete lining thickness are 60cm.Water-break hole engineering geology is configured to alluvium Loessial silty
Loam, ancient soil and the alternate layered distribution of silt loam layer, practical level of ground water are higher than 29.5 meters of hole bottom plate, and the big portion of the soil body is in soft
Mould shape.Since on June 25th, 2007 since construction, because of geologic structure complexity, engineering occurs 8 times compared with landslip, successively attempts
Take excavation technologies and the engineering methods such as the interim inverted arch method of pilot tunnel method under benching tunnelling method, double side wall, three steps, open type shield method.
Three benching tunnelling methods are taken " 9 hole cavitation " method, first after middle drift, digged in two sides under canal axes location arrangements
Tunnel is completed to get out of a predicament or an embarrassing situation and the inverted arch construction arch bracing members of overhanging (installation the first Pin), then excavate in lower pilot tunnel, then two sides
It digs, using steel support structure of getting out of a predicament or an embarrassing situation as interim inverted arch, bench excavation (the arch steel branch of installation the 2nd Pin overhanging in completion
Support), finally upper pilot tunnel, two sides dig in excavation, and step bracing members complete top bar and excavate (peace as interim inverted arch in
Fill the arch bracing members of the 3rd Pin overhanging), it is finally that three layers of step bracing members welding of tunnel are integral, cut off interim inverted arch steel branch
Support forms along hole week closed cyclic annular arch steel support structure is excavated, completes full face tunneling and support work.Three steps are interim
Inverted arch method cooperates advance support that scaffolding structure is taken to guarantee not to soft modeling to reduce face excavation working depth and span
The shape soil body generates disturbance, by increasing the excavation for underpining number and completing tunnel big cross section, manages with Nepal's mud-rock flow tunnel excavation
Thought plays the same tune on different musical instruments, drill footage per month can by the 15m/ month steadily promote, successfully solve under the conditions of weak soil rich water build subterranean tunnel this
One construction difficult problem, it is ensured that water-break hole engineering safety perforation.