Summary of the invention
The object of the invention is to overcome existing above-mentioned deficiency in prior art, the construction method of rich pigment soil sandy silt soil stratum shield structure tool changing with pressure under a kind of railway station track is provided.The risk that when the inventive method has overcome under railway station track tool changing with pressure in rich pigment soil sandy silt soil stratum constructing tunnel, the easy quicksand of rich water weak soil caves in, guarantees the operation security of top railway.
In order to realize foregoing invention object, the invention provides following technical scheme:
A construction method for rich pigment soil sandy silt soil stratum shield structure tool changing with pressure under railway station track, described method comprises the steps:
Preparation before A, tool changing:
Adopt high-pressure rotary jet grouting pile to reinforce the tool changing place soil body; Whether earth's surface in soil stabilization district be there is to hole inspection, if exist hole to utilize cement mortar to carry out shutoff to hole; Feed back to shield structure measuring system by concrete measurement earth's surface tool changing mileage and determine shield machine tool changing place, before shield machine arrives tool changing place, adjust driving attitude and the direction of shield machine, guarantee that shield machine arrives tool changing point smoothly.
Construction parameter adjustment after B, shield machine contact compacted soil:
Shield machine otch slowly reduces support pressure according to detection case after entering compacted soil, and support pressure is not less than 1.5bar; Shield machine shield structure fltting speed is controlled in 1cm/min; Cutter head of shield machine rotating speed is controlled at 1 rev/min; Shield machine shield tail grease is controlled at 29-31kg/ ring.
C, pressure injection swell soil:
Shield structure soil injects swell soil in storehouse, utilizes the radial hole of shield machine fuselage to carry out bentonitic pressure injection to the gap between fuselage and compacted soil.
D, tool changing with pressure:
Determine atmospheric pressure value, determine tool changing atmospheric pressure value in native storehouse according to the Water And Earth Pressures value calculating.
Bring down stocks to build pressure, export the dregs in native storehouse to native storehouse topmost peep hole, after being unearthed, survey situation in native storehouse; Soil is in storehouse in all right situation, continues to be unearthed to 4-6cm place below people's lock, now adopts respirator system to pressurize, and the person of sending someone enters people's lock and observes native storehouse environment; Again be unearthed to shield machine middle part, personnel enter tool changing, and after tool changing, shield machine recovers headwork state.
Wherein, in described steps A, tool changing place soil stabilization adopts φ 600 high-pressure rotary jet grouting piles to reinforce, stake stake overlap joint 200mm, and cement mixing content is 35%, cement 28d compressive strength is not less than 2.0Mpa; Reinforcement depth is below ground 25.45m, and earth's surface 3.45m does not reinforce, and effective reinforcement depth is 22m, and strengthening length is 37.2m, and reinforcing width is 7.6m, guarantees railway security and tool changing safety.
In described steps A, before shield machine arrival tool changing place, adjust driving attitude and the direction of shield machine, guarantee that shield machine arrives tool changing point smoothly, shield machine arrives tool changing place front 30 and encircles driving attitude and the direction of checking a shield machine, encircle the normal range (NR) of adjust to ± 50mm of the attitude of shield structure and tunneling direction by front 15, now cutter head of shield machine stretches out 5cm, prevents that shield structure stabilization zone driving is stuck.
Preferably, in described step B, shield machine shield tail grease is 30kg/ ring.
The swell soil using in described step C adopts thin mould degree sodium bentonite, and bentonite slurry fit quality is than for swell soil: water=250kg:1000kg, and swell soil proportion is 1.2g/
, swell soil viscosity is 35s, guarantees that swell soil injects the good gas retaining after the soil body.
Further, swell soil adopts external pipe directly to carry out pressure injection, and pressure injection mode has two kinds,
1) 5 encircle radial hole pressure injection in shields in advance, set up shield body periphery mud film, swell soil pressure injection, according to pressure control, when pressure is greater than after 5bar, stops pressure injection; Or
2) pressure injection swell soil in native storehouse, sets up face mud film; Set up mud and constantly carry out dregs displacement in native storehouse by conveying worm when unconcerned, the slag going out when conveying worm soil outlet stops displacement while being swell soil; Per tour utilizes fresh bentonite slurry to carry out the maintenance work of face mud desert, and maintenance adopts fresh swell soil to fill Tu Cang.
In described step D, determine that according to the Water And Earth Pressures value calculating native storehouse internal gas pressure value is specially: according to formula P=
calculate Water And Earth Pressures value, in native storehouse, tool changing atmospheric pressure value is than the high 0.1~0.2bar of Water And Earth Pressures value, and wherein P is Water And Earth Pressures value,
for native side direction static balance pressure coefficient,
for the weighted average severe of the soil body, h is center, tunnel buried depth.
compared with prior art, beneficial effect of the present invention:
The inventive method is by reinforcing the tool changing place soil body, adjust attitude of shield machine, tunneling direction and construction parameter, pressure injection swell soil guarantees that it injects the good gas retaining after the soil body, tool changing atmospheric pressure value in the unearthed storehouse of accurate Calculation, and by on-the-spot unmanned warehouse entry test, determine that tool changing atmospheric pressure value carries out tool changing with pressure, safe and reliable, especially under railway station track, in rich pigment soil sandy silt soil stratum constructing tunnel, carry out tool changing with pressure, overcome the risk that the easy quicksand of rich water weak soil caves in, guaranteed the operation security of top railway.
Detailed description of the invention
Below in conjunction with test example and detailed description of the invention, the present invention is described in further detail.But this should be interpreted as to the scope of the above-mentioned theme of the present invention only limits to following embodiment, all technology realizing based on content of the present invention all belong to scope of the present invention.
Under railway of the present invention station track, the construction method of rich pigment soil sandy silt soil stratum shield structure tool changing with pressure is mainly used in rich pigment soil sandy silt soil stratum, comprises the steps:
Preparation before A, tool changing:
Adopt high-pressure rotary jet grouting pile to reinforce the tool changing place soil body, understand in detail railway main track settlement Control standard, uplift capacity≤2mm as per hour in rail track to railway interests; Settling amount≤4mm per hour; Often add up round the clock uplift capacity≤4mm; Often add up round the clock settling amount≤10mm; The two top-of-rail level discrepancy in elevation≤2mm; Accumulative total uplift capacity≤the 10mm of final circuit in half a year; Accumulative total sedimentation≤40mm.In Qian Dui stabilization zone, arrival tool changing region, whether earth's surface there is hole inspection, prevents in process with pressure, and gas is overflowed and cannot be pressurizeed from hole, if exist hole to utilize cement mortar to carry out shutoff to hole; Feed back to shield structure measuring system by concrete measurement earth's surface tool changing mileage and determine shield machine tool changing place, guarantee that shield structure shutdown tool change position is accurate.Before shield machine arrives tool changing place, adjust driving attitude and the direction of shield machine, the attitude of shield structure and tunneling direction are adjusted to normal range (NR), guarantee that shield machine arrives tool changing point smoothly.
Construction parameter adjustment after B, shield machine contact compacted soil:
Shield machine otch slowly reduces support pressure according to detection case after entering compacted soil, and support pressure is not less than 1.5bar; Shield machine shield structure fltting speed is controlled in 1cm/min; Cutter head of shield machine rotating speed is controlled at 1 rev/min; Shield machine shield tail grease is controlled at 29-31kg/ ring.Preferably, shield tail grease is 30kg/ ring.
C, pressure injection swell soil:
Shield structure soil injects swell soil in storehouse, utilizes the radial hole of shield machine fuselage to carry out bentonitic pressure injection to the gap between fuselage and compacted soil.
D, tool changing with pressure:
First determine atmospheric pressure value, determine tool changing atmospheric pressure value in native storehouse according to the Water And Earth Pressures value calculating, concrete, according to formula P=
calculate Water And Earth Pressures value, in native storehouse, tool changing atmospheric pressure value is than the high 0.1~0.2bar of Water And Earth Pressures value, and wherein P is Water And Earth Pressures value,
for native side direction static balance pressure coefficient,
for the weighted average severe of the soil body, h is center, tunnel buried depth.
P=in the specific embodiment of the invention
=0.32*1.85*17.85*1000=1.05bar, atmospheric pressure value is initially set 1.2bar, afterwards according to changing and carry out actual adjustment in ground settlement and native storehouse.In rich pigment soil silty strata, warehouse entry with pressure is to resist underground water soil pressure by air pressure, stops underground water to flow to Tu Cang, to guarantee the certainly steady of sandy soil, prevents from caving in.Determining of atmospheric pressure value played very important effect to the safety in tool changing construction with pressure.
Then, bring down stocks to build pressure, export the dregs in native storehouse to native storehouse topmost peep hole, after being unearthed, survey situation in native storehouse; Soil in all right situation, continues to be unearthed to 4-6cm place, people's lock below, 5cm place below preferred people's lock in storehouse.Now adopt respirator system to pressurize, the person of sending someone enters people's lock and observes native storehouse environment; Again be unearthed to shield machine middle part, personnel enter tool changing, and after tool changing, shield machine recovers headwork state.Tool changing requires to tear one open, fills one.The principle of cutter changing is easy first and difficult later, and disassembling bolts and fastening employing pneumatic impact wrench, guarantee Cutting tool installation manner quality.Adding Decompression Controlling must have professional to operate, and in strict accordance with " 0.6~3.0kgf/
tunnel hyperbar operation decompression table " carry out operation.
Tool changing place is positioned at intensive below, railway station track, for ensureing railway and tool changing safety, in advance tool changing place is reinforced, in described steps A, tool changing place soil stabilization adopts φ 600 high-pressure rotary jet grouting piles to reinforce, stake stake overlap joint 200mm, cement mixing content is 35%, and cement 28d compressive strength is not less than 2.0Mpa; Reinforcement depth is below ground 25.45m, and earth's surface 3.45m does not reinforce, and effective reinforcement depth is 22m, and strengthening length is 37.2m, and reinforcing width is 7.6m, guarantees railway security and tool changing safety.
Preferably, in described steps A, before shield machine arrival tool changing place, adjust driving attitude and the direction of shield machine, shield machine arrives tool changing place front 30 and encircles driving attitude and the direction of checking a shield machine, by the normal range (NR) of adjust to ± 50mm of the attitude of shield structure and tunneling direction, guarantee that shield machine arrives tool changing point smoothly by front 15 rings.Now cutter head of shield machine stretches out 5cm, prevents that shield structure stabilization zone driving is stuck.
Under railway station track, the tool changing construction with pressure of rich pigment soil sandy silt soil stratum shield structure is excessive risk operation, before construction, need to personnel check UP, machinery overhauls and all goods and materials need be reached the spot and enough, especially, the swell soil using in described step C adopts thin mould degree sodium bentonite, and bentonite slurry fit quality is than being swell soil: water=250kg:1000kg, and swell soil proportion is 1.2g/
, swell soil viscosity is 35s, and needs within 24 hours, to carry out mixing fermentation in advance, guarantees that it injects good gas retaining, sealing after the soil body, thereby prevents in process with pressure, gas is overflowed and cannot be pressurizeed.
Further, swell soil adopts external pipe directly to carry out pressure injection, and pressure injection mode has two kinds,
1) 5 encircle radial hole pressure injection in shields in advance, set up shield body periphery mud film, swell soil pressure injection, according to pressure control, when pressure is greater than after 5bar, stops pressure injection; Or
2) pressure injection swell soil in native storehouse, sets up face mud film; Set up mud and constantly carry out dregs displacement in native storehouse by conveying worm when unconcerned, the slag going out when conveying worm soil outlet stops displacement while being swell soil; Per tour utilizes fresh bentonite slurry to carry out the maintenance work of face mud desert, and maintenance adopts fresh swell soil to fill Tu Cang.
Briefly explain as an example of Hangzhou Subway Line 1 example below, as depicted in figs. 1 and 2, interval tool changing place, Hangzhou Subway Line 1 Qiu Tao way station to station, station, city is positioned at the 11st station track, railway terminal, station, city, the 12nd station track (parking line, ballast aggregate railway roadbed) between, distance is pasted Shahe 2 riverbank 25m, center, tunnel buried depth 17.7m, the other about 25m scope in tool changing stabilization zone 1 is pastes Shahe 2, Project Areas superficial part underground water belongs to porosity diving type, main tax is stored in that upper layer is banketed and large layer silt, in flour sand, Source Of Supply is mainly Atmospheric precipitation and surface water, and be recharge connection each other with river embankment, groundwater table is with seasonal variety.It is 0.50m left and right under earth's surface that water level is superlatively descended in place annual mean, and the reinforcing tool changing district water yield is very abundant.This region Tunnel Passing soil layer is sandy silt; Tunnel upper formation is miscellaneous fill, sandy silt, sandy silt folder flour sand; Understratum, tunnel is silty clay, easily liquefaction of flour sand vibration, easily Collapse Deformation, under groundwater effect, easily produce quicksand, carry out tool changing with pressure in this region and have very big risk, adopted the construction method of rich pigment soil sandy silt soil stratum shield structure tool changing with pressure under railway of the present invention station track, the safety that shield machine has been constructed in this region along having guaranteed of determining, overcome the risk that the easy quicksand of rich water weak soil caves in, guaranteed the operation security of top railway.And because tool changing with pressure under rich pigment soil sandy silt soil stratum railway station track is that the whole nation is the first, between this Project Areas, left and right tape is pressed the successful implementation of tool changing, has ensured railway and follow-up safety of passing through useless stake, has also filled up the blank of Hangzhou Subway construction simultaneously.
By reference to the accompanying drawings embodiments of the present invention are described in detail above; but the present invention is not limited to above-mentioned embodiment; in the ken possessing those of ordinary skill in the art, can also make various variations, within these variations all belong to protection scope of the present invention.