Background technology
(in the tunneling construction process of shield structure diameter 6~6.5m), synchronous grouting is building gap between the filling soil body and section of jurisdiction annulus and the main means that reduce the later stage distortion, also is one important procedure in the shield structure propelling construction to adopt shield method to carry out subway tunnel.Require in the shield structure propelling construction slip casting should be in time, evenly, the pressure injection of capacity, guarantee that its structure void obtains in time and the filling of capacity, and make surface deformable and section of jurisdiction side-play amount be reduced to minimum thus.
For satisfying above requirement, in the shield construction of present subway tunnel, generally adopt three kinds of different synchronization slip casting construction technologies: the single liquid slurry of inertia, hardening capacity cement list liquid slurry and cement paste-water glass biliquid slurry.The construction of the single liquid slurry of inertia adopts that consistometric value is higher, workability preferably slurries carry out pressure injection, therefore better to the filling effect of structure void, the instant sedimentation in ground in the time of simultaneously under the situation that guarantees grouting pressure, also controlling the shield structure preferably and deviate from the shield tail, but inert slurry is not because slurries self have solid body intensity, the slip casting rate is bigger, tunnel later stage distortion after building up is bigger with sedimentation, for example, adopt its long-term settlement value maximum of tunnel of inert slurry construction can reach 13cm according to monitoring and statistics to the Shanghai Underground Line 1 after building up.Though hardening capacity cement list liquid slurry can make the slurries around the section of jurisdiction form higher fine and close solid body, but it is short to exist the slurries up time in the practice of construction process, the slurries plugging of easily emanating, it is not convenient to construct, shortcomings such as the thin slip casting rate of slurries is bigger are mainly used wider in the good ground consisting of hard rock of independence.The two fluid grouting method that adopts cement paste to mix with water glass, have short, the solid body intensity of slurries height slurries time of setting, certain antiseepage, impervious effect are arranged, the initial stage sedimentation and the stability in tunnel can have been controlled preferably, but domesticly have a following deficiency when using the dual-fluid synchronous slip casting construction: 1. easily stop up, operation control requires high; 2. grouting amount is 180~250% of theoretical value approximately, and grouting cost is higher; 3. inject the slurries ground settlement that easily causes not in place, will adopt secondary after-teeming slurry usually.
Chinese patent application CN200610147635.X discloses a kind of super big diameter mud water balance simultaneous grouting slurry for tunnel shield construction, these slurries have than great, sand factor is high, shearing resistance yield strength height, the little advantage of solid body shrinkage factor of later stage, in the construction in super-large diameter tunnel, improvement in conjunction with shield-tunneling construction equipment and technology, play good construction effect, can control the distortion of surrounding soil and stablizing of tunnel effectively.But in the Metro Tunnel construction, be subjected to site condition and shield-tunneling construction spatial constraints, problems have appearred in this simultaneous grouting slurry in application process, the corresponding synchronous grouting construction process can't be realized, ground slurry equipment scarce capacity for example, reinforced inaccuracy in the slurry preparation process, labour intensity height, slurries quality control difficulty, workability is poor, and efficient is low in the course of conveying, easily stops up, plugging is frequent in the shield grouting process, slip casting efficient deficiency etc.
Summary of the invention
The present invention is directed to and the similar single slurries of the disclosed super big diameter mud water balance simultaneous grouting slurry for tunnel shield construction of Chinese patent application CN200610147635.X, provide a kind of should the synchronization slip casting construction technology of list slurry applications in constructing metro tunnel, advance the shield tail structure void that produces to fill up the shield structure, thereby reach control because the space produces the surrounding soil cause is out of shape, controlling ground settlement purpose such as in code requirement.
Shield synchronization slip casting construction technology of the present invention, it in turn includes the following steps:
A) injecting paste material is mixed made single slurries by stirring feeding system at agitator;
B) the single slurries that finish by transportation system's system of will mixing are delivered in the shield structure slurry storage tank;
C) the shield grouting system carries out synchronous grouting to shield tail structure void;
Wherein, steps A) the initial slump of single slurries is 9-14cm in, and sand factor is 50-60%, proportion 〉=1.9kg/L, bleeding rate≤5%, anti-shearing yield strength 8h 〉=800pa, solid body shrinkage factor of later stage≤1%; Step C) grouting pressure P=P in
1+ P
2, P wherein
1Be this slip casting point outside water and soil force value, P
2Be the Grouting Pipe pressure loss, its steps A) in single slurries comprise: the hydrated lime of the sand of 50-60%, the flyash of 15-20%, 4-5%, the water of the swell soil of 2.5-3%, the additive of 0.15-0.25% and 15-25% preferred 20%.According to equipment situation in the shield structure, the pumping test by slurries before starting draws, and general grouting pressure is 0.3-1MPa, and grouting amount is 150% of a theoretical value, can adopt 4 slip castings simultaneously of shield tail, grouting amount top and the bottom ratio 6: 4.
Steps A) injecting paste material is mixed being made single slurries by stirring feeding system at agitator, is to concentrate to stir to produce, and concrete technology is as follows:
Mixing the slurry feeding system is by storage bin, water source, weighing device, pay-off and 3m
3Forced action type mortar mixer 5 parts are formed, after obtaining the instruction of command and control system, weigh respectively by charging sequence, be delivered to mixer then and mix system, mixing time is 2~3 minutes, and charging sequence is to add swell soil, flyash, hydrated lime, 2/3 water, sand, additive, 1/3 water under the stirring successively, after the system of mixing is finished, single slurries are put into the olive car, carry out the system of mixing of next injecting paste material then.
The performance requirement of the sand in the injecting paste material, flyash, lime, swell soil and additive is as shown in table 1.
The performance requirement of table 1 injecting paste material
Size performance control index is as shown in table 2.
Table 2 size performance control index
Preferably, the initial slump of single slurries is at 9~12cm, bleeding rate≤3%, anti-shearing yield strength 8h 〉=1000Pa.
Step B) the single slurries that finish by transportation system's system of will mixing are delivered in the shield structure slurry storage tank, and transportation system comprises olive car, on-the-spot slurries receiving system, interim slurry storage tank, down-hole fortune slurry car, and concrete technology is as follows:
Single slurries are sent in the olive car, put into interim slurry storage tank after the vibrations of ground slurries receiving system, filtration, and the grouting amount situation that the volume of interim slurry storage tank is looked the every ring of shield driving should be at least greater than 6m
3, and keep evenly stirring continuously; In a construction period, (advance a ring), travel to assigned address in the down-hole by fortune slurry car, after simultaneously the slurry storage tank administrative staff being sent instruction, single slurries that the slurry storage tank administrative staff will store are opened under stirring and are sent slurry valve to be delivered in the fortune slurry car of down-hole, when fortune slurry car is transported in the tunnel shield structure slurry storage tank position with slurries, open the agitating function of fortune slurry car, to slurries uniformity, workability up to standard after, screw pump by fortune slurry car bottom is delivered in the shield structure slurry storage tank again, carries out the pumping construction operation of slurries.The slurries transport courses is as follows:
Step C) the shield grouting system carries out synchronous grouting to shield tail structure void, carries out when advancing, and concrete technology is as follows:
Filling system is by high-performance grouting pump (Chinese patent application CN200910045387.1 shield tunneling synchronous mud injecting pump, or ksp12-2D grouting pump (business men: German Shi Weiying)) (grouting pump maximum pressure 6MPa, maximum stream flow 2 * 100L/min), hydraulic power station and flow, pressure sensor device is formed, after obtaining the control system of grouting instruction, single slurries that induction system is sent here by setting pressure (on, lower limit), flow is pressed in the injected hole of specifying the orientation, and determine actual grouting amount by metering device, parameter adjustment grouting pressure by the electrical system feedback, flow, until finishing slip casting, finish the pumping of 4 slip casting points simultaneously by a pump, treat that a construction period finishes back (advancing a ring), carries out the work of next construction period.
Shield synchronization slip casting construction technology of the present invention also can comprise step D) the effect detection system monitors and effect detection slip casting, technology is specific as follows: form by monitor and detect two parts in the thing afterwards, wherein, monitoring comprises contents such as slurry consistency, the slump, proportion, bleeding rate and/or anti-shearing yield strengths in the thing, and monitoring is to carry out in the slip casting process in the thing; Detect afterwards and comprise contents such as slurries later strength, solid body shrinkage factor of slurries later stage and/or ground settlement monitoring, detect is to finish in slip casting to carry out after finishing with construction period afterwards.
Another object of the present invention is to provide a kind of single slurries that are adapted to the metro shield synchronous grouting, it comprises: 50~60% sand, 15~20% flyash, 4~5% hydrated lime, 2.5 the water of~3% swell soil, 0.15~0.25% additive and 15~25%, preferred 20%.Wherein, described additive is a LC-H type polycarboxylate efficient mortar water reducing agent, and water-reducing rate reaches 20%.
In the shield synchronization slip casting construction technology of the present invention, slurries have higher anti-shearing yield strength, and the up time is long, and workability is good, are difficult for advantages such as segregation plugging; Slurries by the optimization of equipment, technology, have guaranteed the workability and the quality of slurries in the system of mixing, transportation; In the slip casting process, slurries have reached good compliance and mortar depositing construction effect; The effect detection system detects and estimates the construction of slurries, thereby instructs next step synchronous grouting construction, and technology is continued to optimize.The slurries cost of production is low in the technology of the present invention, and the slip casting rate is little, and grouting amount is low, does not need secondary supplement slip casting, and surface deformable and sedimentation after the construction are easy to control.
The specific embodiment
With subway tunnel shield-tunneling construction synchronous grouting technology is example, and this tunnel adopts 2 earth pressure balanced shield, EPBSs to carry out tunneling construction, shield structure diameter 6340mm, and prefabricated reinforced concrete section of jurisdiction, lining cutting external diameter 6200mm, internal diameter 5500mm are adopted in lining cutting.More than the edpth of tunnel 14m, the excavation soil layer is mainly based on saturated cohesive soil.
Single slurries of present embodiment comprise 55% sand, 18% flyash, 4.5% hydrated lime, 2.8% sodium bentonite, 0.2% polycarboxylate efficient mortar water reducing agent and 19.5% water, and the performance requirement of each injecting paste material is as shown in table 1.
Steps A) after the instruction of mixing the controlled system of slurry feeding system in the agitator, take by weighing swell soil, flyash, hydrated lime, 2/3 water, sand, additive, 1/3 water successively according to aforementioned proportion, in the forced action type mortar mixer, mix system, mixing time is 2~3 minutes, after the system of mixing is finished, single slurries are put into the olive car.
Step B) after the olive car is reached the spot, single slurries are through the vibrations of receiving system, the interim slurry storage tank of active well intermediate interlayer is put in filtration, treat that down-hole fortune slurry car travels to assigned address in the down-hole, after simultaneously slurry storage tank pipeline personnel being sent instruction, the slurry storage tank administrative staff put into down-hole fortune slurry car by valve with the slurries in the interim slurry storage tank under stirring, when fortune slurry car is transported in the tunnel shield structure slurry storage tank position with slurries, open the agitating function of fortune slurry car, be delivered to again in the shield structure slurry storage tank by fortune slurry car bottom screw pump, carry out the pumping construction operation of slurries.Down-hole fortune slurry car carries agitating function, the tunnel delivery track can't use or the tunnel in can't stir at well head under the situation of normal construction, prevent the segregation precipitation of slurries, guarantee the workability of slurries.Induction system advances circuit to carry out the supply of slurries by threeway to difference, satisfies the slurries supply requirement of two or many tunnel propelling circuits simultaneously.
Step C) after the controlled system command of shield grouting system, single slurries that induction system is sent here are under the setting grouting pressure of 0.3~1MPa, according to shield driving speed, be pressed in the injected hole of specifying the orientation according to flow 40~100L/min, adopt 4 slip castings simultaneously of shield tail, grouting amount top and the bottom ratio 6: 4, injection rate 130%~160%, and determine actual grouting amount by metering device, parameter adjustment flow by the electrical system feedback, grouting pressure is controlled in the 1Mpa, until finishing slip casting, a mortar depositing construction cycle once finishes, and carries out the work of next construction period.
Step D) effect detection: in the slip casting process, carry out in the thing contents such as denseness, the slump, proportion, bleeding rate, anti-shearing yield strength of monitoring slurries; Finish ground settlement monitoring after finishing laggard behaviour with construction period in slip casting.
Various detection effect datas are as shown in table 3.
Table 3 detects effect data
Conclusion: after using shield synchronization slip casting construction technology of the present invention and slurries, various effect datas all adhere to specification and technical standard, and technology and slurries tool were greatly improved more in the past.