CN104295304A - Subway tunnel subsider production method capable of achieving different sedimentation distribution guarantee rates - Google Patents

Abstract

The invention belongs to the technical field of civil engineering, and discloses a subway subsider production method used for generating and predicting ground surface subsider curves caused by subway underground excavation or shield tunnels. The subway subsider production method mainly includes the steps of subsider curve generation, subsider envelop curve generation and sedimentation prediction parameter calculation, and specifically includes the steps of obtaining the distances between all monitoring points and the central line of a tunnel, obtaining the sedimentation values of the monitoring points, calculating a regression subsider curve, setting the envelop ratios of the monitoring points, conducting adjustment with the regression subsider curve as the foundation to obtain the maximum envelop curve and the minimum envelop curve, setting the diameter and the burial depth of the tunnel, and calculating the maximum subsider coefficient, the minimum subsider coefficient, the regression subsider coefficient, the maximum area loss rate, the minimum area loss rate and the regression area loss rate of each of the three curves. According to the method, the distribution rule and the distribution range of the ground surface sedimentation caused by underground excavation or shield tunnels are formed by taking actual monitoring data as the foundation and considering the probability distribution of settlement, the prediction parameter of the distribution range is formed, and the method is high in practicability, convenient to use and wide in application prospect.

Description

A kind of subway tunnel subsider generation method realizing different sedimentation distribution fraction

Technical field

Patent of the present invention belongs to technical field of civil engineering, generates for causing the subsider of ground settlement in constructing metro tunnel.

Background technology

Along with the development of urban rail transit construction, the ground settlement that its tunneling or shield-tunneling construction cause is always by engineering circles is paid close attention to, and engineer is based upon on the basis of practical experience mostly to the prediction of ground settlement at present, and lacks systematicness and hand down.By theoretical or numerical simulation (no matter being finite element, finite difference or discrete element), only can reflect sedimentation distribution and the regularity of distribution, be difficult to prediction to quantitative, parameter adjustment dispersion is comparatively large, finally still ascribes micro-judgment to.Due to the complexity (impact of soil body skewness, urban road surfaces structure, the uncertainty of underground water, ambient conditions is complicated, construction method is different, construction team is uneven) of geotechnical engineering, larger by theory analysis, accurately predicting ground settlement value difficulty.Therefore, by the regression analysis to a large amount of measured data, matching predictor formula and curve distribution, just become the practical approach of prediction Metro or Surface Settlement Resulted by Shield Tunneling.But the concrete implementation step of the method is comparatively loaded down with trivial details at present, and practicality is not high, cannot promote to engineers and technicians, and the curve obtained is only one, truly cannot reflect on-site actual situations.

Summary of the invention

The object of patent of the present invention is to provide a kind of easy to use, is easy to operate and passes through revise and consider that the subway tunnel subsider curve generation method of sedimentation distribution fraction solves above-mentioned shortcoming.Concrete technical scheme is as follows:

One, subsider curve generates

(1) set monitoring point, and obtain the distance x of each monitoring point far from tunnel center line, and the sedimentation value y of monitoring point.

(2) carry out regression analysis to measured data (x, y), regression formula is obtain constant term and obtain curve equation $y=S_{\max }\exp (-\frac{x^2}{{2i}^2}),$ Wherein maximum settlement value $S_{\max }=\exp \left(\stackrel{\‾}{a}\right),$ Subsider width $i=1/{\left(\stackrel{\‾}{b}\right)}^{0.5};$

Subsider curve to realize principle as follows: Peck thinks under und rained condition, the volume of the ground settlement groove that tunnel excavation is formed should equal the volume of Stratum Loss, and suppose that stratum is lost on whole length of tunnel and be uniformly distributed, the ground settlement cross direction profiles that constructing tunnel produces is approximately normal distribution, and use for reference the evaluation method being caused surface settlement displacement in mining by exploitation of mineral resources, propose following predictor formula:

$y=S_{\max }\exp (-\frac{x^2}{{2i}^2})$

In formula: both sides, y-tunnel are transversely apart from the surface settlement of center, tunnel x distance; Both sides, x-tunnel are transversely apart from the distance at center, tunnel; S _max-earth's surface maximum settlement; I-curve inflection point is apart from tunnel centre distance.Curve synoptic diagram is shown in Fig. 1.

In order to effectively measured data can be utilized, and ensure the validity of Fitting Analysis, based on Peck formula, linear regression is carried out to it, because Peck formula is nonlinear function, first to its linear transfor.Taken the logarithm in formula (1) both sides, obtain formula (2):

$y=S_{\max }\exp (-\frac{x^2}{{2i}^2})---\left(1\right)$ $\ln y=\ln S_{\max }-\frac{x^2}{{2i}^2}---\left(2\right)$

Now, with ln y and for regression variable is analyzed, wherein ln S _maxfor regression constant item, with for the linear coefficient returned.

Formula after recurrence is

By returning the parameter obtained reverse S _maxand i, namely

$S_{\max }=\exp \left(\stackrel{\‾}{a}\right),i=1/{\left(\stackrel{\‾}{b}\right)}^{0.5}$

Thus (1) formula that turns back to can obtain the Peck curve after returning.

Two, the generation of subsider envelope curve

Because subsider regression curve is only a curve, only can react the regularity of distribution that tunneling or shield tunnel construction cause ground settlement in actual applications, the actual conditions of ground settlement cannot be reacted from amount.And in practice of construction process, technician is more it is of concern that bored tunnel excavation causes the numerical value of ground settlement.Due to the complexity of soil layer condition, accurately provide settlement prediction amount more difficult, but can by based on actual monitoring result, at the enterprising Row sum-equal matrix in basis of the sedimentation regularity of distribution (subsider regression curve), by envelope ratio, namely consider the probability distribution of sedimentation, the scope that ground settlement occurs can be doped.

(3) initial maximum envelope curve is calculated with initial minimum envelop curve $y_2={\mathrm{\α}}_{\min }{S}_{\max }\exp (-\frac{x^2}{{2i}^2}),$ Wherein ${\mathrm{\α}}_{\max }=\frac{y_{\max }}{S_{\max }},{\mathrm{\α}}_{\min }=\frac{y_{\min }}{S_{\max }},$ Y _maxand y _minbe respectively above tunnel center line, i.e. the maximum measured value of the monitoring point sedimentation value at x=0 place and minimum measured value.

(4) largest enveloping curve is calculated with minimum envelop curve wherein β _min, β _maxcomputational methods as follows: β _min, β _maxinitial value be 1, monitoring point is traveled through, each monitoring point is brought into initial maximum envelope curve and initial minimum envelop curve respectively far from the distance measure of tunnel center line, obtain two sedimentation value y ', y respectively "; if the sedimentation value that monitoring point records is at y ', y " between, then this monitoring point is recorded as envelope point, and β _maxbe worth constant; Otherwise, if the sedimentation value that monitoring point records is not at y ', y " between, then by largest enveloping line subsider width beta _maxincrease by 0.01, simultaneously minimum envelop line subsider width beta _minreduce 0.01; After monitoring point traversal terminates, calculate the ratio that all envelopes point accounts for monitoring point quantity, if be greater than or equal to given envelope ratio, then stop iteration, obtain current iteration β _min, β _maxoutput valve; Otherwise iteration again.β when next iteration starts _min, β _maxbe last iteration β _min, β _maxoutput valve.Final forming curves figure as shown in Figure 2.

The calculating of three, settlement prediction parameter

(5) the edpth of tunnel H of bored tunnel is set, the envelope ratio of tunnel diameter D and Tested settlement data;

(6) calculated curve recurrence subsider coefficient k and return area loss late V, design formulas is: and i=kH, wherein D is the tunnel diameter that step (5) sets, and H is the edpth of tunnel that step (5) sets; Calculate largest enveloping curve maximum settlement groove coefficient k ₁with maximum area loss late V ₁, design formulas is: β _maxi=k ₁h; Calculate minimum envelop curve minimum subsider coefficient k ₂, minimum area loss late V ₂, design formulas is: β _mini=k ₂h;

(7) by returning subsider coefficient k, returning area loss late V, maximum settlement groove coefficient k ₁, minimum subsider coefficient k ₂, maximum area loss late V ₁, minimum area loss late V ₂preliminary Forecast and evaluation can be made to the ground settlement that metro built by mining method produces.

Beneficial effect:

Patent of the present invention forms the regularity of distribution and the distribution that bored tunnel causes ground settlement based on the monitored data of reality, forms the Prediction Parameters of distribution, has practical, feature easy to use, is expected to obtain application.

Accompanying drawing illustrates:

Fig. 1 Peck curve synoptic diagram

Largest enveloping line and minimum envelop line chart after Fig. 2 regression curve, correction

Fig. 3 flow chart of the present invention

Fig. 4 monitoring point numerical value extracts figure

Specific embodiment

Concrete grammar comprises the following steps, and flow chart is shown in Fig. 3:

(1) extract monitoring point, and obtain the distance x of each monitoring point far from tunnel center line, and the sedimentation value y of monitoring point, as shown in Figure 4;

(2) the edpth of tunnel H of bored tunnel is set, the envelope ratio of tunnel diameter D and Tested settlement data;

(3) carry out regression analysis to measured data (x, y), regression formula is obtain constant term and obtain curve equation $y=S_{\max }\exp (-\frac{x^2}{{2i}^2}),$ Wherein maximum settlement value $S_{\max }=\exp \left(\stackrel{\‾}{a}\right),$ Subsider width $i=1/{\left(\stackrel{\‾}{b}\right)}^{0.5};$

(4) initial maximum envelope curve is calculated with initial minimum envelop curve $y_2={\mathrm{\α}}_{\min }{S}_{\max }\exp (-\frac{x^2}{{2i}^2}),$ Wherein ${\mathrm{\α}}_{\max }=\frac{y_{\max }}{S_{\max }},{\mathrm{\α}}_{\min }=\frac{y_{\min }}{S_{\max }},$ Y _maxand y _minbe respectively above tunnel center line, i.e. the maximum measured value of the monitoring point sedimentation value at x=0 place and minimum measured value;

(5) largest enveloping curve is calculated with minimum envelop curve wherein β _min, β _maxcomputational methods as follows: β _min, β _maxinitial value be 1, monitoring point is traveled through, each monitoring point is brought into initial maximum envelope curve and initial minimum envelop curve respectively far from the distance measure of tunnel center line, obtain two sedimentation value y ', y respectively "; if the sedimentation value that monitoring point records is at y ', y " between, then this monitoring point is recorded as envelope point, and β _maxbe worth constant; Otherwise, if the sedimentation value that monitoring point records is not at y ', y " between, then largest enveloping line subsider width is increased by 0.01, minimum envelop line subsider width reduces 0.01 simultaneously; After monitoring point traversal terminates, calculate the ratio that all envelopes point accounts for monitoring point quantity, if be greater than or equal to given envelope ratio, then stop iteration, obtain β _min, β _max, otherwise iteration again;

(6) calculated curve recurrence subsider coefficient k and return area loss late V, design formulas is: and i=kH, wherein D is the tunnel diameter that step (2) sets, and H is the edpth of tunnel that step (2) sets; Calculate largest enveloping curve maximum settlement groove coefficient k ₁with maximum area loss late V ₁, design formulas is: β _maxi=k ₁h; Calculate minimum envelop curve minimum subsider coefficient k ₂, minimum area loss late V ₂, design formulas is: β _mini=k ₂h;

(7) by returning subsider coefficient k, returning area loss late V, maximum settlement groove coefficient k ₁, minimum subsider coefficient k ₂, maximum area loss late V ₁, minimum area loss late V ₂preliminary Forecast and evaluation can be made to the ground settlement that metro built by mining method produces.

Claims (1)

1. one kind realizes the subway tunnel subsider generation method of different sedimentation distribution fraction, it is characterized in that comprising the following steps:

(1) set monitoring point, and obtain the distance x of each monitoring point far from tunnel center line, and the sedimentation value y of monitoring point;

(2) the edpth of tunnel H of bored tunnel is set, the envelope ratio of tunnel diameter D and Tested settlement data;

(3) carry out regression analysis to measured data (x, y), regression formula is obtain constant term and obtain curve equation $y=S_{\max }\exp (-\frac{x^2}{{2i}^2}),$ Wherein maximum settlement value $S_{\max }=\exp \left(\stackrel{\‾}{a}\right),$ Subsider width $i=1/{\left(\stackrel{\‾}{b}\right)}^{0.5};$

(4) initial maximum envelope curve is calculated with initial minimum envelop curve $y_2={\mathrm{\α}}_{\min }{S}_{\max }\exp (-\frac{x^2}{{2i}^2}),$ Wherein ${\mathrm{\α}}_{\max }=\frac{y_{\max }}{S_{\max }},{\mathrm{\α}}_{\min }=\frac{y_{\min }}{S_{\max }},$ Y _maxand y _minbe respectively above tunnel center line, i.e. the maximum measured value of the monitoring point sedimentation value at x=0 place and minimum measured value;

(5) largest enveloping curve is calculated with minimum envelop curve wherein minimum envelop line subsider width beta _min, largest enveloping line subsider width beta _maxcomputational methods as follows: β _min, β _maxinitial value be 1, monitoring point is traveled through, each monitoring point is brought into initial maximum envelope curve and initial minimum envelop curve respectively far from the distance measure of tunnel center line, obtain two sedimentation values y', y respectively "; if the sedimentation value that monitoring point records is at y ', y " between, then this monitoring point is recorded as envelope point, and β _min, β _maxbe worth constant; Otherwise, if the sedimentation value that monitoring point records is not at y', y " between, then upgrade β _min, β _max, by largest enveloping line subsider width beta _maxincrease by 0.01, simultaneously minimum envelop line subsider width beta _minreduce 0.01; After monitoring point traversal terminates, calculate the ratio that all envelopes point accounts for monitoring point quantity, if be greater than or equal to given envelope ratio, then stop iteration, obtain β _min, β _max, otherwise iteration again;

(6) calculated curve recurrence subsider coefficient k and return area loss late V, design formulas is: and i=kH, wherein D is the tunnel diameter that step (2) sets, and H is the edpth of tunnel that step (2) sets; Calculate largest enveloping curve maximum settlement groove coefficient k ₁with maximum area loss late V ₁, design formulas is: β _maxi=k ₁h; Calculate minimum envelop curve minimum subsider coefficient k ₂, minimum area loss late V ₂, design formulas is: β _mini=k ₂h;

(7) by returning subsider coefficient k, returning area loss late V, maximum settlement groove coefficient k ₁, minimum subsider coefficient k ₂, maximum area loss late V ₁, minimum area loss late V ₂preliminary Forecast and evaluation can be made to the ground settlement that metro built by mining method produces.