CN110046470A - A kind of shield driving causes ground settlement method for determination of amount after work - Google Patents

A kind of shield driving causes ground settlement method for determination of amount after work Download PDF

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CN110046470A
CN110046470A CN201910394388.0A CN201910394388A CN110046470A CN 110046470 A CN110046470 A CN 110046470A CN 201910394388 A CN201910394388 A CN 201910394388A CN 110046470 A CN110046470 A CN 110046470A
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soil
shield driving
shield
curve
layer
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陈仁朋
孟凡衍
吴怀娜
陈拴
杨微
刘源
康馨
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Hunan University
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Hunan University
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    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00Computer-aided design [CAD]
    • G06F30/20Design optimisation, verification or simulation
    • G06F30/23Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06QDATA PROCESSING SYSTEMS OR METHODS, SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL, SUPERVISORY OR FORECASTING PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL, SUPERVISORY OR FORECASTING PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q50/00Systems or methods specially adapted for specific business sectors, e.g. utilities or tourism
    • G06Q50/08Construction

Abstract

The present invention relates to underground structrue engineering technical field, discloses a kind of shield driving and cause ground settlement method for determination of amount after work, including obtain soil layer information, Soil Parameters, Tunnel Design parameter, shield machine design parameter and shield driving parameter;It takes soil and e-log p' curve is formed by indoor consolidation test, and obtain the q- γ of each soil layer by undrained triaxial compression testsCurve;The soil body shearing strain of different location after shield driving is obtained by Three-dimension Numerical Model;Determine disturbance degree SDD;Apparent weight stress, apparent yield stress, swelling index and the cake compressibility that each layer soil body after shield driving disturbance is determined based on disturbance degree SDD, the e-log p' curve after forming disturbance;E-log p' curve determines subsidence value after work after being disturbed according to shield driving.The present invention carries out control to surrounding formations deformation and building protection provides theoretical foundation and directive function compared to not considering that the Ground surface settlement of settlement after construction was more scientific, more reliable in the past.

Description

A kind of shield driving causes ground settlement method for determination of amount after work
Technical field
The present invention relates to underground structrue engineering technical field, cause ground settlement after work more particularly to a kind of shield driving Method for determination of amount.
Background technique
In recent years, to alleviate urban traffic pressure of increasingly sharpening, the construction that the whole nation mostly has started urban track traffic is high Tide.Shield method has that high degree of automation, the construction period is short, does not influence the features such as traffic above-ground, in coastal soft clay area city It gains great popularity in tunnel construction.Since shield tail gap causes ground loss, shield tunnel inevitably causes in construction period Ground settlement, while disturbance is generated to surrounding formations.Soft soil layer has the characteristics that highly sensitive, high-compressibility, after being disturbed Shearing strength reduces, and can cause long-time secondary consolidation, generates biggish settlement after construction, influence is often ignored, to underestimate Influence of the tunnel construction to surrounding enviroment.Excessive settlement after construction, it will lead to neighboring buildings composition deformation, inclination, cracking, even The serious accidents such as house collapse.Therefore at the beginning of engineering construction, consider ground disturbance caused by shield driving, Accurate Prediction Ground settlement after work caused by shield driving, and propose corresponding stratum deformation control measure and surrounding building safeguard measure The safety and service performance that guarantee surrounding building are had a very important significance.
By the retrieval discovery to existing technical literature, ground settlement research caused by current Shield Tunnel in Soft Ground is many It is more, but based on immediate settlement caused by the ground loss with work progress.As Peck in 1969 in the 7th international soil mechanics Immediate settlement monitoring data, which are based on, with " soft soil layer deep basal pit and tunnel excavation " that Foundation Engineering Conference is delivered proposes that tunnel is opened Ground settlement empirical equation caused by digging.Wei Gang in 2007 " rock-soil mechanics " deliver " ground loss draws in shield-tunneling construction Rise surface subsidence prediction " in propose the unified ground movement pattern of ground settlement caused by ground loss.Li Zhong is superfine Shield is proposed in " Strata Deformations in Shield Tunneling and the boring parameter relationship in soft clay " that " journal of Zhejiang university " is delivered within 2015 The significant relation that boring parameter influences ground settlement and ground loss ratio.Lee K.M. and Rowe R.K. " are being calculated in 1990 Machine and geo-technology periodical " " the three-dimensional formation limited deformation member caused by soft clay tunnel excavation simulation: I analysis method " delivered Stratum settlement caused by shield driving is analyzed using Finite Element Method, hereafter relevant numerical simulation is innumerable.However, The studies above only considers the immediate settlement of shield tunnel construction, can not determine caused long-term settlement after construction after construction disturbance.
In view of this, it is desirable to provide a kind of shield driving causes ground settlement method for determination of amount after work, with accurate evaluation Subsidence value after work caused by shield driving reduces the influence that Shield Construction Method Used deforms surrounding formations.
Summary of the invention
The purpose of the invention is to can more accurately assess subsidence value after work caused by shield driving, one is provided Kind shield driving causes ground settlement method for determination of amount after work.
In order to solve the above technical problem, the present invention provides the determination sides that a kind of shield driving causes subsidence value after work Method includes the following steps:
S1, soil layer information, Soil Parameters, Tunnel Design parameter, shield machine within the scope of shield-tunneling construction influence depth are determined Design parameter and shield driving parameter;
S2, live boring extracting soil, and including following sub-step in no particular order: shield S21, is obtained by indoor consolidation test The consolidation test e-log p' curve of each soil layer undisturbed soil and manipulated soil in structure construction infection depth bounds determines undisturbed soil oneself Weight stress σz0, precosolidation pressure σpc, swelling index Cs, cake compressibility CcWith the cake compressibility C of manipulated soilcr;S22, pass through not Draining triaxial compression test obtains the q- γ of each soil layersCurve determines the destruction shearing strain γ of each soil layerf
S3, Three-dimension Numerical Model simulation tunnel support, excavation and slip casting process are established, to obtain different positions after shield driving The soil body shearing strain γ sets
S4, according to calculation formula SDD=(γsf) × 100% determines disturbing for the soil body of different location after shield driving Dynamic degree SDD;
S5, the weight stress σ based on undisturbed soil before the disturbance degree SDD combination shield drivingz0, precosolidation pressure σpc、 Swelling index CsWith cake compressibility CcWith the cake compressibility C of manipulated soilcr, determine each layer soil body after shield driving disturbance it is apparent from Weight stress σzd, apparent yield stress σpd, swelling index CsdWith cake compressibility Ccd, form the e-log p' curve after disturbing;
S6, disturbed according to shield driving after e-log p' curve determine subsidence value S after workpt
Preferably, in the step S1, the soil layer information is the soil obtained in the depth bounds by boring extracting soil Sample carries out screen analysis test, determines each grain group grogs content of soil sample, and wherein boring extracting soil amount is determined according to test specimen amount, the examination Part amount includes at least three.
It is highly preferred that the shield machine design parameter includes the length of shield machine, diameter, shield shell bullet in the step S1 Property modulus and Poisson's ratio;The shield driving parameter includes shield support power and slip casting rate.
It is further preferred that in the sub-step S21, the scene boring extracting soil refers to along tunnel axis compartment of terrain with taking Earthenware obtains live soil sample, and the soil sample quantity includes at least three.
Specifically, in the sub-step S21, the weight stress σ of the undisturbed soilz0It is determined by following formula:
In formula, γiFor i-th layer of native natural density, buoyant weight degree is taken to level of ground water soil layer below;hiIt is native for i-th layer Thickness.
More specifically, in the sub-step 21, the precosolidation pressure σpcIt determines by the following method:
Find out the smallest point A of radius of curvature from the consolidation test e-logp' curve, cross A point be horizontal line A1 and Tangent line A2;Make to press from both sides bisector of angle A3, bisector A3 and the consolidation test e- between the horizontal line A1 and tangent line A2 The extended line of straightway in logp' curve intersects at B point;The B point is corresponding on the consolidation test e-logp' curve Effective stress value is precosolidation pressure σpc
Further specifically, in the sub-step 21, the swelling index CsIt determines by the following method:
According to the initial weight stress p of the sample of the live boring extracting soil1With initial void ratio e0In the consolidation test B is determined in the coordinate system of e-logp' curve1Point;Cross b1It is being averaged for indoor rebound curve and recompression curve that point, which makees slope, The straight line of slope, wherein the interior rebound curve and recompression curve are the composition portion of the consolidation test e-logp' curve Point;The straight line with b point, the b met at by the vertical line of the B point1B line is the original recompression curve of sample, this is original to press again Contracting slope of a curve is swelling index Cs
The cake compressibility CcIt determines by the following method:
0.42e is equal to by void ratio on interior compression curve0Determine c point;It connects b point and c point forms bc straight line, the bc is straight Line is the virgin compression curve of sample, and slope is cake compressibility Cc
As the preferred embodiment of the present invention, in the step S5, the precosolidation pressure of undisturbed soil before shield driving σpcIt is determined by following formula:
σpc=1.30 σz0
As another preferred implementing form of the invention, in the step S5, each layer soil after the shield driving disturbance The apparent weight stress σ of bodyzdIt is determined by following formula:
σzd=(1-SDD) × σz0
The apparent yield stress σ of the soil body after the shield driving disturbancepdIt is determined by following formula:
σpd=(1-SDD) × σpc
The swelling index C of the soil body after the shield driving disturbancesdIt is determined by following formula:
Csd=(1-SDD) × (Cs-Ccr)+Ccr
The cake compressibility C of the soil body after the shield driving disturbancecdIt is determined by following formula:
Ccd=(1-SDD) × (Cc-Ccr)+Ccr
As another preferred implementing form of the invention, in the step S6, subsidence value S after the workptPass through Layerwise summation method is determined according to following formula:
Work as σz0i+Δpi≤σpdiWhen,
Work as σz0i+ΔpipdiWhen,
In formula, SptiFor stratigraphic compression amount after i-th layer of geotechnique;hiFor i-th layer of native thickness;e0iFor i-th layer of native initial apertures Gap ratio;CsdiFor i-th layer of native swelling index after shield driving;σz0i+ΔpiNative vertically there is effect for i-th layer after shield driving Power;σzdiFor i-th layer of native apparent weight stress after shield driving disturbance;CcdiFor i-th layer of native compression after shield driving disturbance Index;σpdiFor i-th layer after shield driving native apparent yield stress.
Shield driving of the invention causes after ground settlement method for determination of amount accurately can assess shield driving after work Work after the settling amount of earth's surface become to the Practical Project soil body so as to the influence that accurate evaluation shield-tunneling construction deforms earth's surface Shape prediction provides more reasonable foundation.
Other features and advantages of the present invention will the following detailed description will be given in the detailed implementation section.
Detailed description of the invention
Fig. 1 is the flow diagram that method is determined in the embodiment of the present invention;
Fig. 2 is the e-log p' curve synoptic diagram of undisturbed soil in the embodiment of the present invention;
Fig. 3 is the q- γ of undisturbed soil in the embodiment of the present inventionsCurve synoptic diagram;
Fig. 4 is shield driving model schematic diagram in the embodiment of the present invention;
Fig. 5 is shield driving model schematic diagram in the embodiment of the present invention;
Fig. 6 is the e-log p' curve synoptic diagram of the soil body after disturbing in the embodiment of the present invention.
Description of symbols
1 shield machine, 2 shield lining
3 surrounding soil, 4 undisturbed soil
5 disturbed soil, 6 manipulated soil
Specific embodiment
Below in conjunction with attached drawing, detailed description of the preferred embodiments.It should be understood that this place is retouched The specific embodiment stated is merely to illustrate and explain the present invention, and is not intended to restrict the invention.
Such as Fig. 1, the present invention provides a kind of shield driving and causes ground settlement method for determination of amount after work, including walks as follows It is rapid:
S1, soil layer information, Soil Parameters, Tunnel Design parameter, shield machine within the scope of shield-tunneling construction influence depth are determined Design parameter and shield driving parameter;
S2, live boring extracting soil, and including following sub-step in no particular order: shield S21, is obtained by indoor consolidation test The consolidation test e-log p' curve of each soil layer undisturbed soil 4 and manipulated soil 6, determines undisturbed soil 4 in structure construction infection depth bounds Weight stress σz0, precosolidation pressure σpc, swelling index Cs, cake compressibility CcWith the cake compressibility C of manipulated soil 6cr;S22, lead to Cross the q- γ that undrained triaxial compression test obtains each soil layersCurve determines the destruction shearing strain γ of each soil layerf
S3, Three-dimension Numerical Model simulation tunnel support, excavation and slip casting process are established, to obtain different positions after shield driving The soil body shearing strain γ sets
S4, according to calculation formula SDD=(γsf) × 100% determines disturbing for the soil body of different location after shield driving Dynamic degree SDD;
S5, the weight stress σ based on undisturbed soil 4 before the disturbance degree SDD combination shield drivingz0, precosolidation pressure σpc, swelling index CsWith cake compressibility CcWith the cake compressibility C of manipulated soil 6cr, determine the table of each layer soil body after shield driving disturbance See weight stress σzd, apparent yield stress σpd, swelling index CsdWith cake compressibility Ccd, form the e-log p' curve after disturbing;
S6, disturbed according to shield driving after e-log p' curve determine subsidence value S after workpt
It should be noted that shield-tunneling construction influence depth range refers to 2 times of buried depth of tunnel models of earth's surface to earth's surface or less It encloses, wherein buried depth of tunnel takes ground to tunnel center line distance.Soil layer information is to obtain the depth by boring extracting soil Soil sample in range carries out screen analysis test, each grain group grogs content of soil sample is determined, with reference to China " native classification standard " (GBJ145-90) differentiate great soil group, divide soil layer, wherein boring extracting soil amount is determined according to test specimen amount, and the test specimen amount includes at least Three.Soil Parameters refer to that reference " Standard for test methods of earthworks " (GB/T 50123-1999) determines soil by soil test Severe γ, initial void ratio e0, cohesive strength c, internal friction angleSecant modulusMain load tangent modulusUnloading/ Reload modulusThe parameters such as elastic modulus E ' and Poisson's ratio ν.Tunnel Design parameter refers to that buried depth of tunnel, section of jurisdiction are thick Degree, section of jurisdiction ring width, tunnel outer diameter, prefabricated pipe section modulus of elasticity of concrete, wherein prefabricated pipe section modulus of elasticity of concrete is with reference to " mixed Xtah Crude Clay structure design specification " (GB 50010-20102015 editions).Shield machine design parameter refers to the length of shield machine, diameter, shield Shell elasticity modulus and Poisson's ratio.Shield driving parameter refers to shield support power and slip casting rate.Indoor consolidation test is by a scale The soil body sample of very little round pie be placed in lateral deformation is completely limited, upper and lower ends can by consolidation apparatus that permeable stone drains, Then ascending on it to apply vertical stress p step by stepi, during the test, under certain stage pressure after stabilization by consolidation step by step It is decompressed to required pressure, then multistage loadings again, mark is stablized in the compressive deformation for reaching requirement to the soil body under every first class pressure After standard, the deflection Δ S of sample is measured and recordediAfterwards, then apply next stage pressure, until completing the afterbody of test requirements document Until pressure, e-log p' curve is then drawn according to test data, concrete operations require to refer to " Standard for test methods of earthworks " (GB/T 50123-1999).Undrained triaxial compression test refers to holds referring to ASTM standard's (ASTM standard) Row, takes three groups of confining pressures to be tested.Undisturbed soil refers to the soil sample for keeping natural structure and state, referring to " architectural engineering geology Exploration and sampling technique regulation " (JGJ/T87-2012) acquisition.Manipulated soil refers to undisturbed soil drying, pulverizes, according still further to original state The density and moisture content of soil are again manufactured to be tested with soil.E-logp' curve refers to: compressed by indoor consolidation test, Single logarithmic coordinates relationship of void ratio and vertical pressure during rebound, recompression.Three-dimension Numerical Model, which refers to, utilizes finite element The three-dimensional resinous model that software is established, model length can use the length of entire running tunnel, and width takes buried depth of tunnel 15~20 times, model depth is taken as 2 times of buried depth of tunnel.It selects suitable cell type to carry out grid dividing, and inputs Corresponding Soil Parameters and parameters for tunnel, setting model boundary condition.Wherein, it is free boundary that model boundary condition, which is surface, Bottom surface is fixed boundary, and surrounding then only allows that the displacement along gravity direction occurs, and is contacted between tunnel and soil using conode, Assume interface without relative movement.
Preferably, in the sub-step S21, the scene boring extracting soil, which refers to, to be obtained along tunnel axis compartment of terrain with soil sampler Enchashment field soil sample, the soil sample quantity include at least three.
It is highly preferred that in the sub-step S21, the weight stress σ of the undisturbed soil 4z0It is determined by following formula:
In formula, weight stress σz0Refer to the soil body by self gravitation effect existing stress.γiFor i-th layer of native day Right severe takes buoyant weight degree to level of ground water soil layer below;hiFor i-th layer of native thickness.
It is further preferred that in the sub-step 21, the precosolidation pressure σpcIt determines by the following method: from described The smallest point A of radius of curvature is found out on consolidation test e-logp' curve, is crossed A point and is horizontal line A1 and tangent line A2;Make the water Bisector of angle A3, the straight line in bisector A3 and the consolidation test e-logp' curve are pressed from both sides between horizontal line A1 and tangent line A2 The extended line of section intersects at B point, and B point effective stress value corresponding on the consolidation test e-logp' curve is earlier Consolidation pressure σpc.In formula, precosolidation pressure σpcRefer to the soil body suffered maximum vertical effective stress in consolidation process.
Further, in the sub-step 21, the swelling index CsIt determines by the following method:
According to the initial weight stress p of the sample of the live boring extracting soil1With initial void ratio e0In the consolidation test B is determined in the coordinate system of e-logp' curve1Point;Cross b1It is being averaged for indoor rebound curve and recompression curve that point, which makees slope, The straight line of slope, wherein the interior rebound curve and recompression curve are the composition portion of the consolidation test e-logp' curve Point;The straight line with b point, the b met at by the vertical line of the B point1B line is the original recompression curve of sample, this is original to press again Contracting slope of a curve is swelling index Cs
The cake compressibility CcIt determines by the following method:
0.42e is equal to by void ratio on interior compression curve0Determine c point;It connects b point and c point forms bc straight line, the bc is straight Line is the virgin compression curve of sample, and slope is cake compressibility Cc
In approach described above, undisturbed soil swelling index CsRefer to the slope of original recompression curve.Undisturbed soil compression refers to Number CcRefer to the slope of undisturbed soil virgin compression curve straightway.
As a preferred embodiment of the present invention, in the step S5, the precosolidation of undisturbed soil before shield driving Pressure σpcIt is determined by following formula:
σpc=1.30 σz0
As another preferred implementing form of the invention, in the step S5, each layer soil after the shield driving disturbance The apparent weight stress σ of bodyzdIt is determined by following formula:
σzd=(1-SDD) × σz0
The apparent yield stress σ of the soil body after the shield driving disturbancepdIt is determined by following formula:
σpd=(1-SDD) × σpc
The swelling index C of the soil body after the shield driving disturbancesdIt is determined by following formula:
Csd=(1-SDD) × (Cs-Ccr)+Ccr
The cake compressibility C of the soil body after the shield driving disturbancecdIt is determined by following formula:
Ccd=(1-SDD) × (Cc-Ccr)+Ccr
It is further preferred that in the step S6, subsidence value S after the workptBy layerwise summation method according to following Formula determines:
Work as σz0i+Δpi≤σpdiWhen,
Work as σz0i+ΔpipdiWhen,
In formula, SptiFor stratigraphic compression amount after i-th layer of geotechnique;hiFor i-th layer of native thickness;e0iFor i-th layer of native initial apertures Gap ratio;CsdiFor i-th layer of native swelling index after shield driving;σz0i+ΔpiNative vertically there is effect for i-th layer after shield driving Power;σzdiFor i-th layer of native apparent weight stress after shield driving disturbance;CcdiFor i-th layer of native compression after shield driving disturbance Index;σpdiFor i-th layer after shield driving native apparent yield stress.
Shield driving of the invention causes after ground settlement method for determination of amount accurately can assess shield driving after work Work after the settling amount of earth's surface become to the Practical Project soil body so as to the influence that accurate evaluation shield-tunneling construction deforms earth's surface Shape prediction provides more reasonable foundation.
The present invention is described in detail combined with specific embodiments below, and following embodiment will be helpful to the technology of this field Personnel further understand this hair, but the invention is not limited in any way, it is noted that the ordinary skill people of this field For member, in the case where not departing from design of the invention, various modifications and improvements can be made.These belong to protection of the invention Range.
Ningbo soft soil layer subway tunnel uses shield construction, and shield-tunneling construction process causes surrounding formation generation to be disturbed It is dynamic.Using the method for the invention, subsidence value after work caused by shield driving is determined.The specific implementation steps are as follows:
S1, determine that soil layer information, Soil Parameters, Tunnel Design parameter and shield within the scope of shield-tunneling construction influence depth are dug Into parameter.
It drills to survey by scene and determines site soil layers and physical and mechanical parameter are as follows: 1.1It bankets, 0~2.6m of buried depth, severe γ=18.5kN/m3, initial void ratio e0=0.95, cohesive strength c=5.0kPa, internal friction angleSecant modulusMain load tangent modulusUnloading/reloading modulusPoisson's ratio ν=0.20;②1Sandy silt, 2.6~8.9m of buried depth, severe γ=18.9kN/m3, initial void ratio e0=0.895, cohesive strength C=3.0kPa, internal friction angleSecant modulusMain load tangent modulus Unloading/reloading modulus Poisson's ratio ν=0.34;②3Muddy Bottoms silty clay, 8.9~15.0m of buried depth, Severe γ=18.1kN/m3, initial void ratio e0=1.06, cohesive strength c=18.0kPa, internal friction angleSecant mould AmountMain load tangent modulusUnloading/reloading modulus Poisson Than ν=0.34;②4Muddy Bottoms clay, 15.0~18.0m of buried depth, severe γ=17.3kN/m3, initial void ratio e0=1.61, Cohesive strength c=19.0kPa, internal friction angleSecant modulusMain load tangent modulusUnloading/reloading modulus Poisson's ratio ν=0.32;③2Silty clay, buried depth 18.0 ~20.5m, severe γ=18.7kN/m3, initial void ratio e0=0.924, cohesive strength c=16kPa, internal friction angle Secant modulus Main load tangent modulusUnloading/reloading modulusPool Pine ratio ν=0.32;④1Muddy Bottoms silty clay, 20.5~22.7m of buried depth, severe γ=17.9kN/m3, initial void ratio e0= 1.1, cohesive strength c=6.0kPa, internal friction angleSecant modulusMain load tangent modulusUnloading/reloading modulusPoisson's ratio ν=0.32;④2Clay, buried depth 22.7~ 27.4m, severe γ=17.5kN/m3, initial void ratio e0=1.263, cohesive strength c=8.0kPa, internal friction angleIt cuts Linear modulusUnloading/reloading modulusPoisson's ratio ν= 0.32;⑤2Silty clay, 27.4~30.8m of buried depth, severe γ=19.3kN/m3, initial void ratio e0=0.81, cohesive strength c =15.3kPa, internal friction angleSecant modulusMain load tangent modulusIt unloads Load/reloading modulus Poisson's ratio ν=0.3;⑥2Silty clay, 27.4~30.8m of buried depth, severe γ= 18.6kN/m3, initial void ratio e0=0.977, cohesive strength c=18.3kPa, internal friction angleSecant modulus Main load tangent modulusUnloading/reloading modulusPoisson's ratio ν= 0.32。
It is investigated and determines that tunnel axis buried depth is 13.5m, outer diameter 6.2m;Shield lining 2 is with a thickness of 0.35m, ring width 1.2m, elasticity modulus 34.5MPa;Shield machine is in the shape of a hoof, and overall length 8.4m, point diameter 6.39m, tail end diameter is 6.2m, shield shell elasticity modulus are 2.3e8kN/m2, Poisson's ratio 0.15.Shield support power is Ps=1.0P0, wherein P0For tunnel Soil pressure at axis buried depth;Slip casting rate is 100%.
S2, live boring extracting soil, and including following sub-step in no particular order: shield S21, is obtained by indoor consolidation test The consolidation test e-log p' curve of each soil layer undisturbed soil and manipulated soil in structure construction infection depth bounds determines undisturbed soil oneself Weight stress σz0, precosolidation pressure σpc, swelling index Cs, cake compressibility CcWith the cake compressibility C of manipulated soilcr;S22, pass through not Draining triaxial compression test obtains the q- γ of each soil layersCurve determines the destruction shearing strain γ of each soil layerf
In sub-step S21, the weight stress of undisturbed soilWherein σz0For depth any below ground Vertical effective weight stress at z, unit kPa;N is the soil layer sum in depth z range;γiFor i-th layer of native natural weight Degree, takes buoyant weight degree, unit kN/m to level of ground water soil layer below3;hiFor i-th layer of native thickness, unit m.
Live boring extracting soil is simultaneously pressed by the e-logp ' that indoor consolidation test obtains each calculating soil layer undisturbed soil and manipulated soil Contracting curve.The precosolidation pressure σ of undisturbed soil is determined using A.Cassagrandepc, swelling index Cs, cake compressibility CcAgain Mould the cake compressibility C of soilcr.With 2.4It is Muddy Bottoms clay undisturbed soil and manipulated soil shown in Fig. 2 for Muddy Bottoms clay layer E-logp' curve.The smallest point A of radius of curvature is found out from e-logp' curve, is crossed A point and is horizontal line A1 and tangent line A2;Make The bisector A3 of horizontal line A1 and tangent line A2, bisector A3 prolong with the straightway in the consolidation test e-logp' curve Long line intersects at B point;Effective stress corresponding to the B point is exactly precosolidation pressure σpc.The initial void ratio e of soil0=1.61, Precosolidation pressure σpc=1.30 σz0, swelling index Cs=0.253, cake compressibility Cc=0.541, the cake compressibility C of manipulated soilcr =0.296.
In sub-step S22, each soil layer undisturbed soil sample is taken, in three groups of difference confining pressure (pco=45kPa, 90kPa, 150kPa) Under the conditions of carry out undrained triaxial test (ASTM standard), the limit of each soil layer under the conditions of different confining pressures is drawn based on test data Deviation stress q and shearing strain γsRelation curve, determine the destruction shearing strain γ of soil layerf.With 2.3For Muddy Bottoms clay layer, Fig. 3 is q- γ of Muddy Bottoms clay undisturbed soil under the conditions of different confining pressuressCurve, it can be obtained from the figure that, the destruction of Muddy Bottoms clay is cut Strain γf=5.28%.
S3, Three-dimension Numerical Model simulation tunnel support, excavation and slip casting process are established, to obtain different positions after shield driving The soil body shearing strain γ sets
Three-dimension Numerical Model, simulation tunnel support, excavation and slip casting are established according to engineering is practical using finite element software Journey is as shown in Figure 4 and Figure 5.The symmetry for considering load and geometric dimension, is modeled using axial symmetry, i.e., model scope takes long (L) × wide (B) × depth (D)=150m × 80m × 45m, shield shell use 6 gusset plate unit simulations, and shield lining 2 and soil layer use 10 The interaction of the simulation of node sphenoid, tunnel and surrounding soil 3 uses 12 node contact unit simulations.Wherein shield lining 2 Linear elastic model is used with shield shell, surrounding soil 3 inputs corresponding model parameter using hardening (HS) model, and determines model Boundary condition are as follows: bottom is fixed boundary, and surface is free boundary, and surrounding allows the displacement along gravity direction.
Tunnel support is simulated by activation tunnel-liner unit and excavation face supporting power, then removes tunnel inside circumference soil 3 unit simulation tunnel excavation of body simulates slip casting process finally by adjustment tunnel-liner face shrinking percentage.Tunnel is controlled in the present embodiment Road face shrinking percentage Cg=2%, then slip casting rate Gr=(1-Cg× 100) × 100%=100%, excavation face supporting power Ps=1.0P0, P in formula0For the earth pressure at rest at tunnel axis buried depth, P0=K0∑γihi=167.8kPa, K in formula0For Muddy Bottoms clay layer Coefficient of static earth pressure, K is measured by Flat Dilatometer Test0=0.67.
Initial field stress balance uses K in finite element analysis step setting0Consolidation, and set displacement in latter calculating step Zero, then basis makes a reservation for construction operating condition setting Construction Analysis step, is provided with and checks errorless rear submission calculating task, can obtain It must make a reservation for the soil body shearing strain γ under construction operating condition after shield drivings.It is poor that the shearing strain distribution of surrounding soil 3 spatially exists The opposite sex, its shearing strain of the different location of same soil layer be not also identical.Therefore equal with the length immediately below tunnel bottom on the direction x, y For 1m, buried depth is zoning thickness 0.6m for the Muddy Bottoms clay of 16.6m~17.2m, according to numerical simulation result, pick The mean effective stress σ of the region soil body after into disturbancez0+ Δ p=92.55kPa, average shearing strain γs=1.88%.
S4, according to calculation formula SDD=(γsf) × 100% determines disturbing for the soil body of different location after shield driving Dynamic degree SDD.
According to the shearing strain γ of the soil body after shield drivingsWith the destruction shearing strain γ of the soil bodyfIt can determine the disturbance degree of the soil body SDD=(γsf) × 100%.Then disturbance degree SDD=(1.88/5.28) × 100%=35.61% of the zoning
S5, the weight stress σ based on undisturbed soil before the disturbance degree SDD combination shield drivingz0, precosolidation pressure σpc、 Swelling index CsWith cake compressibility CcWith the cake compressibility C of manipulated soilcr, determine each layer soil body after shield driving disturbance it is apparent from Weight stress σzd, apparent yield stress σpd, swelling index CsdWith cake compressibility Ccd, form the e-log p' curve after disturbing.
It is 1m with the length immediately below tunnel bottom on the direction x, y, buried depth is the Muddy Bottoms clay of 16.6m~17.2m For, it is to calculate point with zoning center, z=16.9m, groundwater level depth 1.0m are then calculated before shield driving at this time The weight stress σ of layerz0:
σz0=1 × 18.5+1.6 × 8.5+6.3 × 8.9+6.1 × 8.1+1.9 × 7.3=151.45kPa
σpc=1.30 σz0=1.30 × 151.45=196.89kPa
The apparent weight stress σ of the soil body after shield driving disturbancezdIt is determined by following formula:
σzd=(1-SDD) × σz0=(1-0.3561) × 151.45=97.52kPa
The apparent yield stress σ of the soil body after shield driving disturbancepdIt is determined by following formula:
σpd=(1-SDD) × σpc=(1-0.3561) × 196.89=126.77kPa
The swelling index C of the soil body after shield driving disturbancesdIt is determined by following formula:
Csd=(1-SDD) × (Cs-Ccr)+Ccr=(1-0.3561) × (0.253-0.296)+0.296=0.268
The cake compressibility C of the soil body after shield driving disturbancecdIt is determined by following formula:
Ccd=(1-SDD) × (Cc-Ccr)+Ccr=(1-0.3561) × (0.541-0.296)+0.296=0.454
It to sum up can be calculated the e-logp' curve of Muddy Bottoms clay after shield driving disturbs, as shown in Figure 6.
S6, disturbed according to shield driving after e-log p' curve determine subsidence value S after workpt
The apparent weight stress σ of the soil body after being disturbed according to shield drivingzd, apparent yield stress σpd, swelling index CsdAnd pressure Contracting index Ccd, ground settlement S after the work after shield driving is determined using layerwise summation methodpt, foundation width b takes tunnel outer diameter, i.e., B=6.2m, 4 <b≤8m, lift height Δ z=0.8m (Code for design of building GB50007-2011), wherein stratification The level and underground water level of soil are naturally to be layered face, and ground settlement is the sum of decrement after each work for calculating soil layer after work, Due to thicker soil, the number of plies is more, soil body shearing strain in spatial distribution there is also otherness, but different soil different location Calculation method and process are substantially similar, therefore consider that length reason does not calculate one by one, only choose the direction x, y immediately below tunnel bottom On length be 1m, the Muddy Bottoms clay layer that buried depth is 16.6m~17.2m is used as with reference to being calculated, it is assumed that the layer is tunnel I-th computation layer of earth's surface settlement after construction right above road bottom.
Due to σz0i+Δpi=92.55kPa≤σpdi=126.77kPa, therefore pressed after determining i-th layer of geotechnique using following formula Contracting amount Spti:
Settlement after construction is that negative sign (-) indicates soil body rebound, and above formula is only in σz0i+Δpi≤σpdiShi Chengli works as σz0i+Δpi> σpdiWhen, decrement S after i-th layer of geotechniqueptiIt is determined using following formula:
Wherein, SptiFor decrement after i-th layer of native work, unit m;hiFor i-th layer of native thickness, unit m;e0iFor I-th layer of native initial void ratio;CsdiFor i-th layer of native swelling index after shield driving;σz0i+ΔpiIt is after shield driving i-th The vertical effective stress of layer soil, unit kPa;σzdiFor i-th layer of native apparent weight stress after shield driving disturbance, CcdiFor shield I-th layer of native cake compressibility after structure driving disturbance;σpdiFor i-th layer after shield driving native apparent yield stress, unit kPa.
Similarly, the apparent weight stress σ of layer soil body is respectively calculated after disturbing according to shield drivingzdi, apparent yield stress σpdi, swelling index Csdi, cake compressibility Ccdi, vertical effective stress σz0i+Δpi, computation layer thickness hiAnd initial void ratio e0i Decrement after each layer work can be calculated.
Ground settlement S after work after shield drivingptFor the sum of decrement after each computation layer work, it may be assumed that
It is described the prefered embodiments of the present invention in detail above in conjunction with attached drawing, still, the present invention is not limited to above-mentioned realities The detail in mode is applied, within the scope of the technical concept of the present invention, a variety of letters can be carried out to technical solution of the present invention Monotropic type, these simple variants all belong to the scope of protection of the present invention.
It is further to note that specific technical features described in the above specific embodiments, in not lance In the case where shield, can be combined in any appropriate way, in order to avoid unnecessary repetition, the present invention to it is various can No further explanation will be given for the combination of energy.
In addition, various embodiments of the present invention can be combined randomly, as long as it is without prejudice to originally The thought of invention, it should also be regarded as the disclosure of the present invention.

Claims (10)

1. a kind of shield driving causes ground settlement method for determination of amount after work, which comprises the steps of:
S1, soil layer information within the scope of shield-tunneling construction influence depth, Soil Parameters, Tunnel Design parameter, shield machine design are determined Parameter and shield driving parameter;
S2, live boring extracting soil, and including following sub-step in no particular order: S21, applied by indoor consolidation test acquisition shield The consolidation test e-log p' curve of each soil layer undisturbed soil (4) and manipulated soil (6), determines undisturbed soil within the scope of work influence depth (4) weight stress σz0, precosolidation pressure σpc, swelling index Cs, cake compressibility CcWith the cake compressibility C of manipulated soil (6)cr; S22, the q- γ that each soil layer is obtained by undrained triaxial compression testsCurve determines the destruction shearing strain γ of each soil layerf
S3, Three-dimension Numerical Model simulation tunnel support, excavation and slip casting process are established, to obtain different location after shield driving Soil body shearing strain γs
S4, according to calculation formula SDD=(γsf) × 100% determines the disturbance degree of the soil body of different location after shield driving SDD;
S5, the weight stress σ based on undisturbed soil (4) before the disturbance degree SDD combination shield drivingz0, precosolidation pressure σpc, return A brief period of time number CsWith cake compressibility CcWith the cake compressibility C of manipulated soil (6)cr, determine shield driving disturbance after each layer soil body it is apparent Weight stress σzd, apparent yield stress σpd, swelling index CsdWith cake compressibility Ccd, form the e-log p' curve after disturbing;
S6, disturbed according to shield driving after e-log p' curve determine subsidence value S after workpt
2. shield driving according to claim 1 causes ground settlement method for determination of amount after work, which is characterized in that described In step S1, the soil layer information is to obtain the soil sample in the depth bounds by boring extracting soil to carry out screen analysis test, Determine each grain group grogs content of soil sample, wherein boring extracting soil amount is determined according to test specimen amount, and the test specimen amount includes at least three.
3. shield driving according to claim 1 causes ground settlement method for determination of amount after work, which is characterized in that described In step S1, the shield machine design parameter includes length, diameter, shield shell elasticity modulus and the Poisson's ratio of shield machine (1);Institute The shield driving parameter stated includes shield support power and slip casting rate.
4. shield driving according to claim 1 causes ground settlement method for determination of amount after work, which is characterized in that described In sub-step S21, the scene boring extracting soil, which refers to, obtains live soil sample, the soil sample along tunnel axis compartment of terrain soil sampler Quantity includes at least three.
5. shield driving according to claim 1 causes ground settlement method for determination of amount after work, which is characterized in that described In sub-step S21, the weight stress σ of the undisturbed soil (4)z0It is determined by following formula:
In formula, γiFor i-th layer of native natural density, buoyant weight degree is taken to level of ground water soil layer below;hiFor i-th layer of native thickness Degree.
6. shield driving according to claim 1 causes ground settlement method for determination of amount after work, which is characterized in that described In sub-step 21, the precosolidation pressure σpcIt determines by the following method:
The smallest point A of radius of curvature is found out from the consolidation test e-logp' curve, is crossed A point and is done horizontal line A1 and tangent line A2;Make to press from both sides bisector of angle A3 between the horizontal line A1 and tangent line A2, bisector A3 and the consolidation test e-logp' are bent The extended line of straightway in line intersects at B point;The B point is corresponding on the consolidation test e-logp' curve effect Force value is precosolidation pressure σpc
7. shield driving according to claim 6 causes ground settlement method for determination of amount after work, which is characterized in that described In sub-step 21, the swelling index CsIt determines by the following method:
According to the initial weight stress p of the sample of the live boring extracting soil1With initial void ratio e0In the consolidation test e- B is determined in the coordinate system of logp' curve1Point;Cross b1It is the average oblique of indoor rebound curve and recompression curve that point, which makees slope, The straight line of rate, wherein the interior rebound curve and recompression curve are the component part of the consolidation test e-logp' curve; The straight line with b point, the b met at by the vertical line of the B point1B line is the original recompression curve of sample, and the original recompression is bent The slope of line is swelling index Cs
The cake compressibility CcIt determines by the following method:
0.42e is equal to by void ratio on interior compression curve0Determine c point;It connects b point and c point forms bc straight line, which is The virgin compression curve of sample, slope are cake compressibility Cc
8. shield driving according to claim 1 causes ground settlement method for determination of amount after work, which is characterized in that described In step S5, the precosolidation pressure σ of undisturbed soil before shield drivingpcIt is determined by following formula:
σpc=1.30 σz0
9. shield driving according to claim 1 causes ground settlement method for determination of amount after work, which is characterized in that described In step S5, the apparent weight stress σ of each layer soil body after the shield driving disturbancezdIt is determined by following formula:
σzd=(1-SDD) × σz0
The apparent yield stress σ of the soil body after the shield driving disturbancepdIt is determined by following formula:
σpd=(1-SDD) × σpc
The swelling index C of the soil body after the shield driving disturbancesdIt is determined by following formula:
Csd=(1-SDD) × (Cs-Ccr)+Ccr
The cake compressibility C of the soil body after the shield driving disturbancecdIt is determined by following formula:
Ccd=(1-SDD) × (Cc-Ccr)+Ccr
10. shield driving according to claim 1 causes ground settlement method for determination of amount after work, which is characterized in that institute It states in step S6, subsidence value S after the workptIt is determined by layerwise summation method according to following formula:
Work as σz0i+Δpi≤σpdiWhen,
Work as σz0i+ΔpipdiWhen,
In formula, σz0i+ΔpiFor i-th layer after shield driving native vertical effective stress;σpdiFor i-th layer of native table after shield driving See yield stress;SptiFor stratigraphic compression amount after i-th layer of geotechnique;hiFor i-th layer of native thickness;e0iFor i-th layer of native initial hole Than;CsdiFor i-th layer of native swelling index after shield driving;σzdiFor i-th layer of native apparent weight stress after shield driving disturbance; CcdiFor i-th layer of native cake compressibility after shield driving disturbance.
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