CN105804761B - Construction method suitable for liquefied sand stratum shield near-distance passing through building - Google Patents

Construction method suitable for liquefied sand stratum shield near-distance passing through building Download PDF

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Publication number
CN105804761B
CN105804761B CN201610141899.8A CN201610141899A CN105804761B CN 105804761 B CN105804761 B CN 105804761B CN 201610141899 A CN201610141899 A CN 201610141899A CN 105804761 B CN105804761 B CN 105804761B
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shield
construction
pressure
soil
grouting
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CN105804761A (en
Inventor
任磊
刘永辉
何伟
毕景佩
姚亮亮
李春剑
朱韶彬
朱颖
钱晓华
潘涛
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Zhengzhou Rail Transportation Co Ltd
Shanghai Tunnel Engineering Co Ltd
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Zhengzhou Rail Transportation Co Ltd
Shanghai Tunnel Engineering Co Ltd
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    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/06Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • E21D9/0607Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining the shield being provided with devices for lining the tunnel, e.g. shuttering
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K17/00Soil-conditioning materials or soil-stabilising materials
    • C09K17/02Soil-conditioning materials or soil-stabilising materials containing inorganic compounds only
    • C09K17/10Cements, e.g. Portland cement
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D11/00Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
    • E21D11/04Lining with building materials
    • E21D11/10Lining 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
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/04Driving tunnels or galleries through loose materials; Apparatus therefor not otherwise provided for
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/06Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • E21D9/0621Shield advancing devices
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21DSHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D9/00Tunnels or galleries, with or without linings; Methods or apparatus for making thereof; Layout of tunnels or galleries
    • E21D9/06Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining
    • E21D9/08Making by using a driving shield, i.e. advanced by pushing means bearing against the already placed lining with additional boring or cutting means other than the conventional cutting edge of the shield
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K2103/00Civil engineering use

Abstract

The present invention relates to a kind of construction methods suitable for liquefied sand stratum shield near-distance passing through building, including:Before construction, the geology and environment of boundary of works area are surveyed, data is surveyed in acquisition;According to the technology measure surveyed in Data Design work progress;Monitoring frequency is improved in shield crossing building, the construction parameter in the technology measure is dynamically adjusted according to the monitoring data monitored;In the propelling construction of shield, micro-destabilization slip-casting is carried out for the tube coupling away from 8 ring of shield tail to 10 rings after shield tail is detached from, control grouting pressure is less than or equal to 0.3MPa;And it after the completion of construction, predicts the disturbance operating mode of construction tunnel and formulates corresponding control measure.Shield near-distance passing through building is constructed in liquefied sand stratum, using micro-disturbance Construction Control, can be prevented liquefied sand from being disturbed during shield driving and be liquefied, effective control settlement protects the safety of building.

Description

Construction method suitable for liquefied sand stratum shield near-distance passing through building
Technical field
The present invention relates to shield-tunneling construction fields, refer in particular to a kind of suitable for liquefied sand stratum shield near-distance passing through building Construction method.
Background technology
In Construction of Urban Rail Traffic, a large amount of subway sectional tunnel uses shield construction, and has had accumulated quite Abundant experience.In general, it can preferably predict and control shield driving to the influence caused by ambient enviroment.But In some areas there are liquefying soil stratum, soil liquefaction occurs mainly in based on sandy soil and the higher area of level of ground water Domain, such as:Alluvial plain or girt distributed area that coastal area, river water are passed through etc..These regions are often distributed some and are full of Underground water and the loose sand being saturated, since the structure of themselves is weaker, it is easy to soil texture occur because of external force Change.The Area distributions such as Zhengzhou, Beijing, Wuhan, Shijiazhuang liquefied sand at home, and great risk is brought to shield-tunneling construction, Once causing to disturb to liquefied sand due to construction wrong during shield driving, sand liquefaction is made to become quicksand shape, will made At construction disaster and it is unable to control.
When the liquefaction arenaceous stratum that shield crossing stream plasticity is poor, water content is high, infiltration coefficient is big, there are ground settlement hardly possiblies With control, the soil body by technical barriers such as disturbed liquefaction, quicksands, shield need to pass through existing building and structures in addition, and domestic Correlation experience is insufficient, and great risk is brought to construction.
Character after sand liquefaction and liquefaction is a very complicated problem, although current research obtains certain progress, But still the project for having number of values that must study, such as rationally accurate liquefied method of discrimination, it is particularly suitable for some special knots The liquefaction Judgment Method of structure (such as subterranean tunnel).These are all up for further studying.
Currently, conventional crossing technology measure has the following problems:
Liquefied sand water content is abundant, and water penetration is very strong.Shield generates disturbance when passing through, to the soil body and quicksand easily occurs Or hardened phenomenon;
Water burst caused by sand liquefaction gushes sand phenomenon shield tunneling face is made to lose stable equilibrium, generates excavation face unstability, into And the safety in tunnel itself and periphery construction of structures is had an impact;
Door gushing water after shield tail and screw conveyor gushes sand.The vibrated dynamic pore water pressure of layer of sand increases during shield driving Greatly, it causes to gush.
In the liquefied sand of stability difference, domestic shield crossing construction experience is insufficient, frequently occurs dangerous situation.
Invention content
It is an object of the invention to overcome the deficiencies of existing technologies, provide a kind of suitable for liquefied sand stratum shield low coverage Construction method from passing through building solves to generate to disturb to the soil body present in conventional crossing technology that quicksand or hardened occurs Layer of sand when Sand phenomenon caused by phenomenon, sand liquefaction generates security implication and shield driving to tunnel and building The problems such as gushing caused by vibrated.
Realizing the technical solution of above-mentioned purpose is:
A kind of construction method suitable for liquefied sand stratum shield near-distance passing through building of the invention, including:
Before construction, the geology and environment of boundary of works area are surveyed, data is surveyed in acquisition;
According to the technology measure surveyed in Data Design work progress;
Monitoring frequency is improved in shield crossing building, described apply is adjusted come dynamic according to the monitoring data monitored Construction parameter in work technical measures;
In the propelling construction of shield, micro-destabilization slip-casting is carried out for the tube coupling away from 8 ring of shield tail to 10 rings after shield tail is detached from, Slurries in the micro-destabilization slip-casting are mixed using cement, flyash and water, the slurries in the micro-destabilization slip-casting Slump control is less than or equal to 0.3MPa in 9cm to 11cm, control grouting pressure;And
After the completion of construction, predicts the disturbance operating mode of construction tunnel and formulate corresponding control measure.
The present invention establishes the micro-disturbance Construction Control system of shield tunnel, by surveying prediction and picking out before constructing Select, construct in monitoring measurement and the prediction after technology measure and construction constituted with control, it is preferable to control shield tunnel The disturbance that road is constructed to liquefied sand around shield, prevents the soil body from liquefying, it is ensured that the building along constructing is in good Service state.By implementing micro-destabilization slip-casting at shield machine rear, reduces building settlement, further fill shield-tunneling construction Caused by Stratum Loss.Shield near-distance passing through building is constructed in liquefied sand stratum, using micro-disturbance Construction control skill Art can prevent liquefied sand from being disturbed during shield driving and liquefy, and effective control settlement protects building Safety.
The present invention is suitable for being further improved for the construction method of liquefied sand stratum shield near-distance passing through building According to the technology measure surveyed in Data Design work progress including carrying out shield model selection, to adapt it to described apply The geology and environment of work range;
The parameter of selected shield machine includes:
The aperture opening ratio of shield machine upper tool pan is 40% to 50%;
The rotating speed of shield machine upper slitter dish driving is 0.95rpm to 2.0rpm, and nominal torque is more than or equal to 5500kNm, takes off Tired torque is more than or equal to 6600kNm;
The maximum gross thrust of propulsion system is more than or equal to 40000kN on shield machine;
The grouting pipeline quantity of synchronous grouting is more than or equal to 4 on shield machine;
The injection hole number that system is improved on shield machine is that 5 are arranged on cutterhead;
Shield machine upper tool pan driving power is more than or equal to 900kw, and general power is more than or equal to 1500kw.
The present invention is suitable for being further improved for the construction method of liquefied sand stratum shield near-distance passing through building In, according to the technology measure surveyed in Data Design work progress include soil pressure force value setting:
Active earth pressure value and passive earth pressure value are calculated using formula, the calculation formula of the active earth pressure value isThe calculation formula of the passive earth pressure value isWherein:σaFor active earth pressure value, σpFor passive earth pressure value, γ is the weight of soil Degree, z are earth's surface to tunnel central depths,For the internal friction angle of soil, c is the cohesive strength of soil;
The soil pressure σ of driving face is selected between the active earth pressure value and the passive earth pressure valueHorizontal lateral force
Ground water pressure force value is calculated using formula, in shield tunneling process, chooses the stratum hydraulic pressure in front of shield cutter Force value is current ground water pressure force value;In shield stopping process, the hydraulic pressure force value for choosing shield tail rear portion is current underground Hydraulic pressure force value;
The calculation formula of water flooding pressure value in front of the shield cutter is σBefore w cutterheads=q γWaterhWater, wherein q is according to soil The empirical value that layer osmosis system determines, q is 0.5 to 1.0 in sand, and q is 0.1 to 0.5, γ in cohesive soilWaterFor the capacity of water, hWaterFor the height of distance from groundwater cutter head center;
The calculation formula of the hydraulic pressure force value at the shield tail rear portion is σAfter w shield tails=qMortarγWaterH, wherein qMortarFor according to mortar The empirical value that infiltration coefficient and the turgor of slip casting determine, qMortarIt is 0.5 to 1.0, γWaterFor the capacity of water, h ' is at slip casting With the height difference of cutter head center;
According to the soil pressure σ for the driving face being calculatedHorizontal lateral force, ground water pressure force value and construction soil pressure adjusted value The sum of set soil pressure force value, the difference for controlling practical soil pressure force value in shield tunneling process and setting between soil pressure force value exists Within ± 5%.
The present invention is suitable for being further improved for the construction method of liquefied sand stratum shield near-distance passing through building In including that fltting speed and cutterhead rotating speed control according to the technology measure surveyed in Data Design work progress;
The fltting speed of shield is controlled in 20mm/min to 30mm/min, with stable propulsion in shield tunneling process Speed equilibrium at the uniform velocity promotes;
Cutterhead rotating speed is controlled in 0.9r/min to 1.0r/min.
The present invention is suitable for being further improved for the construction method of liquefied sand stratum shield near-distance passing through building In including synchronous grouting control measure, the synchronous grouting according to the technology measure surveyed in Data Design work progress Grouting serous fluid in control measure includes sand, flyash, bentonite, Yi Jishui, with 240: 260: 40: 140 proportioning stirring At.
The present invention is suitable for being further improved for the construction method of liquefied sand stratum shield near-distance passing through building In the synchronous grouting control measure include control synchronous grouting amount, and synchronous grouting is calculated by grouting amount calculation formula Amount, slip casting is synchronized with 180% to 200% slip casting rate;
The grouting amount calculation formula is Q=V λ, V=π (D2-d2) L/4, wherein:V is fill volume, i.e. shield-tunneling construction Caused gap, λ are slip casting rate, and D is that shield cuts outer diameter, and d is prefabricated pipe section outer diameter, and L is section of jurisdiction ring width.
The present invention is suitable for being further improved for the construction method of liquefied sand stratum shield near-distance passing through building In, the synchronous grouting control measure include control synchronous grouting pressure,
Critical value on grouting pressure is calculated using formula,
Grouting pressure lower critical value is calculated using formula,Wherein:PupFor slip casting Critical value in pressure, PmaFor grouting pressure lower critical value, γ is soil body unit weight, and h is injected hole buried depth, and c is soil body cohesive strength;
The grouting pressure of setting is calculated according to critical value on the grouting pressure and the grouting pressure lower critical value, The grouting pressure that practical grouting pressure tends to setting is controlled in construction;
The grouting pressure of setting is calculated by following formula,Wherein:N is Safety coefficient, P are the grouting pressure of setting.
The present invention is suitable for being further improved for the construction method of liquefied sand stratum shield near-distance passing through building In, carry out micro-destabilization slip-casting when, using single slurry micro-destabilization slip-casting mode, the tube coupling of slip casting is carried out by 1 to 2 injected hole Slip casting, and between the tube coupling of slip casting between be divided into 4 endless tube sections.
The present invention is suitable for being further improved for the construction method of liquefied sand stratum shield near-distance passing through building In in shield driving, into the front of shield and native storehouse, injection bentonite slurry carries out soil improvement, the bentonite slurry Soil ratio be 14:1;Foam is added simultaneously and carries out soil improvement, the foam is molten by the foam of 100% compressed air and 10% Liquid mixes, and the foam solution includes 5% additive foam and 95% water.
Description of the drawings
Fig. 1 is the flow chart for the construction method that the present invention is suitable for liquefied sand stratum shield near-distance passing through building.
Specific implementation mode
The invention will be further described in the following with reference to the drawings and specific embodiments.
The present invention provides a kind of construction methods suitable for liquefied sand stratum shield near-distance passing through building, especially For the liquefaction arenaceous stratum that stream plasticity is poor, water content is high, infiltration coefficient is big, the present invention is directed to study liquefaction arenaceous stratum shield Near-distance passing through building and structures micro-disturbance control construction technology, reduce shield in the construction process and are disturbed to liquefied sand It is dynamic, it is ensured that sand does not generate liquefaction.The present invention proposes the micro-disturbance technology measure in crossing construction, and control is closely worn Building and structure sedimentation caused by more constructing ensure the safety of building and structures, improve on liquefied sand stratum Middle shield driving efficiency.The present invention is applied suitable for liquefied sand stratum shield near-distance passing through building below in conjunction with the accompanying drawings Work method illustrates.
Refering to fig. 1, it is shown that the present invention is suitable for the construction method of liquefied sand stratum shield near-distance passing through building Flow chart.With reference to Fig. 1, it is suitable for the present invention construction method of liquefied sand stratum shield near-distance passing through building It illustrates.
As shown in Figure 1, construction method disturbance of the shield tunnel construction to liquefied sand around shield in order to control of the present invention, Prevent the soil body from liquefying, it is ensured that building and structures along constructing are in good service state, establish shield tunnel The micro-disturbance Construction Control system in road, the micro-disturbance Construction Control system by before constructing survey prediction with choice, Long-term forecast after monitoring measurement in work progress is controlled and constructed with technology measure is constituted with control three parts. The present invention the construction method suitable for liquefied sand stratum shield near-distance passing through building include:
Step S11 is executed, before construction, the geology and environment of boundary of works area are surveyed, data is surveyed in acquisition.Before construction To in prescribed limit engineering geology and environment survey, including the physico-mechanical properties on stratum, hydrogeological characteristic, periphery The state etc. of construction of structures.In addition, must also in construction of structures service stage basis and periphery construction disturbance investigate, And reinforce prospecting density and intensity to passing through part, survey the accurate of data with the method guarantee that a variety of modes of surveying are combined Property.
Step S12 is executed, according to the technology measure surveyed in Data Design work progress, technology measure includes There are shield model selection, soil pressure setting, synchronous grouting control and soil improvement.
Step S13 is executed, monitoring frequency is improved in shield crossing building, construction is adjusted come dynamic according to monitoring data Parameter.It is monitored in the construction process, due to the Unpredictability and for 24 hours continuous that shield-tunneling construction is on building, structures influence Construction, therefore improve monitoring frequency in crossing construction.The measuring point laying of monitoring project need to consider that the construction of each subdivisional work is suitable The factors such as sequence, the relative position relation of the requirement of protected object and shield tunnel, ambient enviroment protection.By to monitoring data Analysis dynamically adjust construction parameter.
Technology measure is controlled, shield-tunneling construction shows as extruding and pine of the shield to the soil body to the disturbance of the soil body Dynamic, loading and unloading, pore water pressure rise and fall cause variation, surface uplift and sinking of soil nature etc..Shield construction draws The immanent cause for playing surrounding formation deformation is that the initial stress state of the soil body is changed so that undisturbed soil experienced extruding, The complicated stress paths such as shearing, distortion.Coverage and degree to liquefied sand disturbance depend on several factors, including: Shield model selection, construction parameter (soil pressure, cutter head torque, propulsive force, grouting amount and grouting pressure etc.), soil mass property, on tunnel The influence etc. of portion's load.The present invention mainly with regard to shield model selection, soil pressure setting, synchronous grouting control, soil improvement etc. into Row research and innovation provides a kind of construction method in the shield crossing construction of structures of liquefied sand stratum.
Include carrying out shield model selection according to the technology measure surveyed in Data Design work progress, to adapt it to State the geology and environment of boundary of works area.Shield machine should be directed to geology characteristic (liquefied sand stratum) and engineering specifications (under wear it is existing Construction of structures) reasonable selection is carried out, it is allowed to adapt to engineering construction requirement.According to this running tunnel feature, have to shield machine as follows It is required that:(1) meet the grittiness geological conditions that liquefies, the construction requirement of parameters for tunnel;(2) engineering-environment is adapted to, it is ensured that engineering safety; (3) its configuration meets construction period;(4) meet the requirement of environmental protection.Shield machine main configuration parameters are shown in Table 1:
Table 1:Shield machine mainly configures, feature and menu
Include the setting of soil pressure force value according to the technology measure surveyed in Data Design work progress, according to earth pressure balance The principle of shield, the pressure in native storehouse must be balanced with the front Water And Earth Pressures of excavation face, to maintain the stabilization of the excavation face soil body, Reduce the disturbance to soil layer.The soil pressure force value of the shield driving in liquefied sand is calculated according to Rankine Earth Pressure principle.
Active earth pressure and passive earth pressure calculate, if the rate of shield machine screw conveyor casting in tunneling process More than cutterhead into native rate, it will cause sealed compartment casting unbalance, cause the reduction of sealed compartment soil pressure, make the soil of driving face Pressure is changed into active earth pressure state by earth pressure at rest state, and the soil body has the trend of slide downward at the top of shield machine, Cause ground settlement.The calculation formula of active earth pressure value isIf shield machine The rate of screw conveyor casting is less than cutterhead into native rate in tunneling process, also sealed compartment casting will be caused unbalance, drawn It plays sealed compartment soil pressure to increase, the soil pressure of driving face is made to be changed into passive earth pressure state by earth pressure at rest state, And the soil body has the trend of upward sliding at the top of shield machine, causes surface uplift.The calculation formula of passive earth pressure value isWherein:σaFor active earth pressure value, σpFor passive earth pressure value, γ is the weight of soil Degree, z are earth's surface to tunnel central depths,For the internal friction angle of soil, c is the cohesive strength of soil;
The soil pressure σ of driving face is selected between active earth pressure value and passive earth pressure valueHorizontal lateral force;From control ground Table settles and from the point of view of preventing sand liquefaction, and rational driving face soil pressure between active earth pressure and should be broken ground Between pressure:σa≤σHorizontal lateral force≤σp
Ground water pressure force value is calculated using formula, in tunneling process, as cutterhead is constantly pushed ahead, the pressure in native storehouse Near primitive soil pressure value, resistance of water when being flowed in soil is considered, water pressure when driving in stratum can be with base area The infiltration coefficient of layer takes the circumstances into consideration to consider.Due to the presence of pressure head difference in stratum, underground water will necessarily constantly be flowed into native storehouse, Until pressure head difference in stratum is eliminated.In shield tunneling process, the stratum water pressure in front of shield cutter is chosen Value is current ground water pressure force value;In shield stopping process, the hydraulic pressure force value for choosing shield tail rear portion is current underground water Pressure value;The calculation formula of water flooding pressure value in front of shield cutter is σBefore w cutterheads=q γWaterhWater, wherein q is to be oozed according to soil layer The empirical value that permeable system determines, q is 0.5 to 1.0 in sand, and q is 0.1 to 0.5, γ in cohesive soilWaterFor the capacity of water, hWaterFor The height of distance from groundwater cutter head center;The calculation formula of the hydraulic pressure force value at shield tail rear portion is σAfter w shield tails=qMortarγWaterH ', wherein qMortar For the empirical value determined according to the turgor of the infiltration coefficient of mortar and slip casting, qMortarIt is 0.5 to 1.0, γWaterFor the appearance of water Amount, h ' are at slip casting and the height difference of cutter head center;
According to the soil pressure σ for the driving face being calculatedHorizontal lateral force, ground water pressure force value and construction soil pressure adjusted value The sum of set soil pressure force value, the difference for controlling practical soil pressure force value in shield tunneling process and setting between soil pressure force value exists Within ± 5%.σInitial settingHorizontal lateral forceHorizontal water pressureAdjustment, in formula:σInitial settingFor the shield soil storehouse soil pressure primarily determined, σHorizontal lateral forceFor horizontal lateral force, σHorizontal water pressureFor stratum water pressure, σAdjustmentTo correct soil pressure of constructing, soil is passed through according to formula calculating The theoretical value of pressure, practical soil pressure setting value are finely adjusted according to settling data analysis, obtain rational construction soil pressure force value, To ensure that the difference between practical soil pressure and setting value controls in ± 5% in progradation simultaneously.
Include fltting speed and the control of cutterhead rotating speed according to the technology measure surveyed in Data Design work progress;It will The fltting speed of shield is controlled in 20mm/min to 30mm/min, even with stable fltting speed equilibrium in shield tunneling process Speed promotes;Cutterhead rotating speed is controlled in 0.9r/min to 1.0r/min.Construction of structures is passed through in liquefied sand stratum to be accomplished: Fltting speed, stringent control shield direction, attitudes vibration are reduced, correction is reduced, especially prevents big value correction, ensures that shield is flat Surely pass through.Meanwhile effective cooperation of cutterhead rotating speed and fltting speed should be passed through, it is ensured that soil immediately ahead of the effective support of cutterhead front Body avoids generating sedimentation in front of branch mask deficiency notch, prevents sand from liquefying.Shield driving speed control is in 20mm/min ~30mm/min, and suitably adjusted according to monitoring data.When passing through section construction, fltting speed is kept to stablize as possible, it is ensured that shield Structure equilibrium is at the uniform velocity passed through, to reduce the disturbance to the periphery soil body, in order to avoid have an adverse effect to structure.The control of cutterhead rotating speed exists 0.9~1.0r/min.
Technology measure further includes amount control of being unearthed, and is constructed in liquefied sand, and amount of being unearthed control is the 98% of theoretical value To 100%, forbid to backbreak.Technology measure further includes TBM's position control, during passing through, because shield carries out plane or height Journey can increase the disturbance to the soil body when rectifying a deviation, therefore in crossing process, it is ensured that shield is good in front sedimentation, to the greatest extent It is likely to reduced shield correction amount and correction number, the disturbance to liquefied sand is reduced, prevents the soil body from liquefying.
Include synchronous grouting control measure according to the technology measure surveyed in Data Design work progress.For infiltration The big liquefied sand stratum of coefficient, synchronous grouting require slurries energy Fast Filling, and water-retaining property is strong, does not isolate, and decantation rate is small, injection After be not easy by underground water dilution fall etc. performances, and must ensure later strength.Therefore synchronous in liquefied sand stratum shield-tunneling construction Injecting paste material must have the gel time of matters, smaller syneresis rate, stronger water resistant dispersibility.
Grouting serous fluid in synchronous grouting control measure is anti-shearing mortar, by sand, flyash, bentonite, with water mix It at high-consistency, high shearing resistance, inertia list liquid mortar, can block water rapidly in liquefied sand, Fast Filling, early strength is high, protects Aqueous strong and be not easy to isolate, which is shown in Table 2:
Flyash Sand Bentonite Water
260 240 40 140
Table 2:Simultaneous grouting slurry matches
Synchronous grouting control measure include control synchronous grouting amount, in shield tunneling process, should use grouting amount and note The standard of slurry pressure dual control is controlled.Grouting amount and grouting pressure are adjusted according to monitoring data into Mobile state.Liquefied sand Slip casting rate generally should be 180%~200% in layer.Synchronous grouting amount is calculated by grouting amount calculation formula, with 180% to 200% slip casting rate synchronizes slip casting.Synchronous grouting amount calculation formula is as follows:
Q=V λ, V=π (D2-d2) L/4, wherein:V is fill volume, i.e. gap caused by shield-tunneling construction, and λ is slip casting Rate, D are that shield cuts outer diameter, and d is prefabricated pipe section outer diameter, and L is section of jurisdiction ring width.
The synchronous grouting control measure include control synchronous grouting pressure, and the optimum value of synchronous grouting pressure should be in synthesis Consider to determine on the basis of foundation condition, equipment performance, slurry characteristics and support pressure.Lower critical grouting pressure PmaUnder must tie up The stabilization for holding top soil block is allowed to not stay;Upper critical grouting pressure PupThe stabilization that must maintain lower part soil block is allowed to not grand It rises.
Critical value on grouting pressure is calculated using formula,
Grouting pressure lower critical value is calculated using formula,Wherein:PupFor slip casting Critical value in pressure, PmaFor grouting pressure lower critical value, γ is soil body unit weight, and h is injected hole buried depth, and c is soil body cohesive strength;
The grouting pressure of setting is calculated according to critical value on the grouting pressure and the grouting pressure lower critical value, The grouting pressure that practical grouting pressure tends to setting is controlled in construction;
The grouting pressure of setting is calculated by following formula,Wherein:N is Safety coefficient, P are the grouting pressure of setting.In fact, grouting pressure is not much different with theoretical formula method value in construction, slip casting For pressure about in 0.3MPa to 0.4MPa, slip casting is to fill rather than cleave to soil layer around under the conditions of this, can prevent soil Body fluid makes slip casting reach ideal effect.
Technology measure further include shield machine tail sealing control, in liquefied sand stratum shield crossing construction build Import Condar spy's seal grease is used in object work progress, and tail sealing effect is controlled by the intrusion and pressure of seal grease Fruit, and whether there is or not spillage phenomenons for observation shield tail in real time, once occur blocking spillage region increase grease intrusion;In addition shield Foam strip is equipped in structure machine as shield tail spillage emergency materials.
Step S14 is executed, in shield driving construction, micro-destabilization slip-casting is carried out for the tube coupling after shield tail, for disengaging shield The tube coupling away from 8 ring of shield tail to 10 rings carries out micro-destabilization slip-casting after tail, and control grouting pressure is less than or equal to 0.3MPa.Carry out micro-disturbance When slip casting, using single slurry micro-destabilization slip-casting mode, slip casting carried out by 1 to 2 injected hole to the tube coupling of slip casting, and slip casting 4 endless tube sections are divided between tube coupling.It is settled to reduce construction of structures, Stratum Loss caused by further filling shield-tunneling construction, The micro-destabilization slip-casting after wall is implemented at shield machine rear.According to monitoring materials, micro-disturbance is carried out after 8~10 ring of shield tail is deviate from section of jurisdiction Slip casting.Using single slurry micro-destabilization slip-casting mode, meet multiple spot, a small amount of, multiple, uniform principle, tunnel longitudinal direction grouting sequence Spacer ring is taken to jump the mode beaten, once 1~2 hole of construction, each two construction 4 ring of central spacer, grouting pressure cross senior general to area per ring The domain soil body is generated compared with large disturbances, therefore is played pipe slip casting and should be reinforced control to grouting pressure in the process, and grouting pressure should be not more than 0.3MPa.Slurries inject stratum by the injected hole of section of jurisdiction, and the mode of propulsion and slip casting linkage is taken in construction, and slip casting is not Reach requirement, shield pause promotes, to prevent the soil body from continuing to deform.Micro-destabilization slip-casting slurries select cement mortar, match (weight Than) it is shown in Table 3:
Cement Flyash Water Slump (cm)
1 3 In right amount 9 to 10
Table 3:Cement mortar proportion
Technology measure further includes soil improvement control, and sediment improvement is tunneled in liquefied sand and needs to solve following ask Topic:
(1) the impermeabilisation ability for improving dregs in native storehouse, avoids the cutterhead front soil body from being caused because of discharging consolidation larger Ground settlement or cave-in accident occur.
(2) internal friction angle of dregs and the cutterhead front soil body in native storehouse is reduced, abrasion of the dregs to knife disc tool is reduced, Reduce cutter head torque.
(3) plasticity for improving dregs in native storehouse, prevents dregs to be adhered on cutterhead and forms mud cake.
(4) since layer of sand dense water is poor, after driving is shut down, sand is easily isolated, is precipitated, is closely knit in native storehouse, makes cutterhead again Torque is big when startup, difficulty in starting, big to shield machine equipment damage.
(5) spewing phenomenon can be generated because dregs dense water is poor when being tunneled using earth pressure balance pattern.
(6) dregs workability is poor, and screw machine is slagged tap unsmooth, causes driving speed slow, and boring parameter is not easy to control.
Present invention employs sodium bentonite slurries and foaming agent as sediment improvement agent, and sediment improvement effect is preferable.It pushes away Into in the process toward Tu Cang and front soil body injection bentonite slurry improvement dregs.Since bentonitic injection is effectively guaranteed soil The pressure in storehouse increases the compactness of layer of sand, reduces liquefaction while allowing layer of sand excess pore water pressure to discharge the occurrence of;Note Enter after bentonite be entirely around shield body it is modified after dregs, reduce grouting at the tail of the shield machine pressure, backfill can be efficiently reduced Stratum Loss reduces ground settlement.
It is tunneled in liquefied sand, if only using bentonite does sediment improvement agent, cutter head torque can be very big, promotes difficult; Foaming agent sediment improvement is only used, soil ratio in native storehouse can be made to become larger, increases risk of gushing, improved effect is also unsatisfactory, and Influence of fluctuations can be caused to the soil pressure in native storehouse, increase the possibility of liquefaction of soil mass.Therefore it tunnels, needs in liquefied sand stratum With the use of bentonite slurry and foaming agent, with bentonite slurry improve based on, the orderly combination supplemented by foaming agent improvement, prevent The liquefaction of sand.
By the practical application in a large number of experiments and construction production, some basic natures of different soil ratio slurries have been summed up Energy:
(1) bentonite slurry that soil ratio is 9: 1 becomes paste, does not have pumping;
(2) bentonite slurry that soil ratio is 12: 1 is more sticky, viscosity 130s, and pumping is poor;
(3) bentonite slurry that soil ratio is 14: 1 is diluter, viscosity 35s, and pumping is preferable.
The ratio for implementing foaming agent in the examination propulsion phase selects work, at the same by experiment determine foaming agent Foam Expansion rate, Consistency of foam and foam injection rate, the composition of foam solution used:Additive foam 5%, water 95%.Foam forms:100% Compressed air and 10% foam solution mix.
Sediment improvement is based on bentonite slurry, supplemented by foaming agent.Using driving speed and consistency is slagged tap as Main Basiss, is fitted When adjust bentonite incorporation and bentonite slurry injection rate;Situation is slagged tap as foundation using cutter head torque and screw machine, is adjusted in due course Whole foaming agent volume and injection rate.
Step S15 is executed, after the completion of construction, the disturbance operating mode of construction tunnel is predicted and formulates corresponding control measure.
Laboratory test results show that the pore water pressure of the soil body is the important indicator of measurement construction disturbance degree, and hole The dissipation and time correlation of water pressure.Under normal circumstances, the ratio that tunnel long-term settlement accounts in total settlement is 30.0% Change between~90.0%.Therefore, it is necessary to be predicted the development of deformation after work and formulate corresponding technical measures for controlling The influence of TERM DEFORMATION processed, to ensure the safety of construction of structures.
Long-term settlement control should take appropriate measures for producing cause, and be built when necessary to the construction of protection Object is reinforced.It carries out the construction disturbance long-term forecast after work and formulates corresponding control measure to be prolonging for micro-disturbance construction technology It stretches, is the means for verifying construction effect.
The present invention is suitable for having the beneficial effect that for the construction method of liquefied sand stratum shield near-distance passing through building:
Construction of structures is closely passed through in liquefied sand stratum has specific aim and validity;
It can prevent liquefied sand from being disturbed during shield driving and liquefy;
It being capable of effective control settlement, guarantee crossing construction and construction of structures peace with micro-disturbance Construction control construction technology Entirely.
The present invention has been described in detail with reference to the accompanying drawings, those skilled in the art can be according to upper It states and bright many variations example is made to the present invention.Thus, certain details in embodiment should not constitute limitation of the invention, this Invention will be using the range that the appended claims define as protection scope of the present invention.

Claims (7)

1. a kind of construction method suitable for liquefied sand stratum shield near-distance passing through building, which is characterized in that including:
Before construction, the geology and environment of boundary of works area are surveyed, data is surveyed in acquisition;
Include the setting of soil pressure force value according to the technology measure surveyed in Data Design work progress:
Active earth pressure value and passive earth pressure value are calculated using formula, the calculation formula of the active earth pressure value isThe calculation formula of the passive earth pressure value isWherein:σaFor active earth pressure value, σpFor passive earth pressure value, γ is native Severe, z are earth's surface to tunnel central depths,For the internal friction angle of soil, c is the cohesive strength of soil;
The soil pressure σ of driving face is selected between the active earth pressure value and the passive earth pressure valueHorizontal lateral force
Ground water pressure force value is calculated using formula, in shield tunneling process, chooses the water flooding pressure value in front of shield cutter For current ground water pressure force value;In shield stopping process, the hydraulic pressure force value for choosing shield tail rear portion is current ground water pressure Force value;
The calculation formula of water flooding pressure value in front of the shield cutter is σBefore w cutterheads=q γWaterhWater, wherein q is to be oozed according to soil layer The empirical value that permeable system determines, q is 0.5 to 1.0 in sand, and q is 0.1 to 0.5, γ in cohesive soilWaterFor the capacity of water, hWaterFor The height of distance from groundwater cutter head center;
The calculation formula of the hydraulic pressure force value at the shield tail rear portion is σAfter w shield tails=qMortarγWaterH ', wherein qMortarFor according to the infiltration of mortar The empirical value that coefficient and the turgor of slip casting determine, qMortarIt is 0.5 to 1.0, γWaterFor the capacity of water, h ' is at slip casting and knife The height difference of disk center;
According to the soil pressure σ for the driving face being calculatedHorizontal lateral force, ground water pressure force value and construction the sum of soil pressure adjusted value Set soil pressure force value, practical soil pressure force value is controlled in shield tunneling process and set difference between soil pressure force value ± Within 5%;
Monitoring frequency is improved in shield crossing building, the construction skill is dynamically adjusted according to the monitoring data monitored Construction parameter in art measure;
In the propelling construction of shield, micro-destabilization slip-casting is carried out for the tube coupling away from 8 ring of shield tail to 10 rings after shield tail is detached from, it is described Slurries in micro-destabilization slip-casting are mixed using cement, flyash and water, the slump of the slurries in the micro-destabilization slip-casting Degree control is less than or equal to 0.3MPa in 9cm to 11cm, control grouting pressure;When carrying out micro-destabilization slip-casting, using single slurry perturbation Dynamic grouting mode, tunnel longitudinal direction grouting sequence take spacer ring to jump the mode beaten, to the tube coupling of slip casting by 1 to 2 injected hole into Row slip casting, and between the tube coupling of slip casting between be divided into 4 endless tube sections, slip casting not up to require when, shield pause promote;And
After the completion of construction, predicts the disturbance operating mode of construction tunnel and formulate corresponding control measure.
2. it is suitable for the construction method of liquefied sand stratum shield near-distance passing through building as described in claim 1, it is special Sign is, includes carrying out shield model selection according to the technology measure surveyed in Data Design work progress, to adapt it to State the geology and environment of boundary of works area;
The parameter of selected shield machine includes:
The aperture opening ratio of shield machine upper tool pan is 40% to 50%;
The rotating speed of shield machine upper slitter dish driving is 0.95rpm to 2.0rpm, and nominal torque is more than or equal to 5500kNm, torsion of getting rid of poverty Square is more than or equal to 6600kNm;
The maximum gross thrust of propulsion system is more than or equal to 40000kN on shield machine;
The grouting pipeline quantity of synchronous grouting is more than or equal to 4 on shield machine;
The injection hole number that system is improved on shield machine is that 5 are arranged on cutterhead;
Shield machine upper tool pan driving power is more than or equal to 900kw, and general power is more than or equal to 1500kw.
3. it is suitable for the construction method of liquefied sand stratum shield near-distance passing through building as described in claim 1, it is special Sign is, includes that fltting speed and cutterhead rotating speed control according to the technology measure surveyed in Data Design work progress;
The fltting speed of shield is controlled in 20mm/min to 30mm/min, with stable fltting speed in shield tunneling process Equilibrium at the uniform velocity promotes;
Cutterhead rotating speed is controlled in 0.9r/min to 1.0r/min.
4. it is suitable for the construction method of liquefied sand stratum shield near-distance passing through building as described in claim 1, it is special Sign is, includes synchronous grouting control measure, the synchronization according to the technology measure surveyed in Data Design work progress Grouting serous fluid in grout injection control measure includes sand, flyash, bentonite, Yi Jishui, is stirred with 240: 260: 40: 140 proportioning It mixes.
5. it is suitable for the construction method of liquefied sand stratum shield near-distance passing through building as claimed in claim 4, it is special Sign is that the synchronous grouting control measure include control synchronous grouting amount, and synchronization is calculated by grouting amount calculation formula Grouting amount synchronizes slip casting with 180% to 200% slip casting rate;
The grouting amount calculation formula is Q=V λ, V=π (D2-d2) L/4, wherein:V is fill volume, i.e. shield-tunneling construction causes Gap, λ be slip casting rate, D be shield cut outer diameter, d be prefabricated pipe section outer diameter, L be section of jurisdiction ring width.
6. it is suitable for the construction method of liquefied sand stratum shield near-distance passing through building as claimed in claim 4, it is special Sign is that the synchronous grouting control measure include control synchronous grouting pressure,
Critical value on grouting pressure is calculated using formula,
Grouting pressure lower critical value is calculated using formula,Wherein:PupFor grouting pressure Upper critical value, PmaFor grouting pressure lower critical value, γ is soil body unit weight, and h is injected hole buried depth, and c is soil body cohesive strength;
The grouting pressure of setting is calculated according to critical value on the grouting pressure and the grouting pressure lower critical value, is applying The grouting pressure that practical grouting pressure tends to setting is controlled in work;
The grouting pressure of setting is calculated by following formula,Wherein:N is safety Coefficient, P are the grouting pressure of setting.
7. it is suitable for the construction method of liquefied sand stratum shield near-distance passing through building as described in claim 1, it is special Sign is, in shield driving, into the front of shield and native storehouse, injection bentonite slurry carries out soil improvement, the bentonite The soil ratio of slurries is 14: 1;Foam is added simultaneously and carries out soil improvement, the foam is by 100% compressed air and 10% bubble Foam solution mixes, and the foam solution includes 5% additive foam and 95% water.
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CN106285710B (en) * 2016-08-23 2018-07-24 中南大学 A kind of earth pressure balanced shield, EPBS boring parameter control method based on earth's surface deformation
CN106547986B (en) * 2016-11-08 2020-01-14 苏州大学 Shield tunnel soil pressure load calculation method
CN108049878B (en) * 2017-11-13 2019-06-25 浙江大学城市学院 A kind of powder land floor shield cuts the construction method that stake is crossed the river
CN108590669B (en) * 2018-04-27 2020-01-31 中铁十二局集团有限公司 Small-section abrupt slope hydraulic tunnel tunneling construction method
CN108643937B (en) * 2018-04-27 2020-01-31 中铁十二局集团有限公司 Prevention and recovery method for hydraulic tunnel lower-crossing residential area
CN108678758A (en) * 2018-04-28 2018-10-19 青岛新华友建工集团股份有限公司 Major diameter slurry shield passes through shanty town settlement Control construction over long distances under the conditions of non-reinforced
CN110595598B (en) * 2019-08-09 2021-07-30 华北水利水电大学 Side slope boulder stability monitoring and early warning method based on Doppler remote laser vibration measurement technology
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