CN103558360A - Method for measuring rainfall capacity of critical unstable starting of rainfall type landslide - Google Patents

Abstract

The invention relates to a determination method for determining critical destabilization starting rainfall capacity of rainfall type landslide by using a monitoring mode, in particular to a determination method for comprehensively analyzing and determining critical destabilization starting rainfall capacity of rainfall type landslide based on real-time monitoring data of rainfall capacity and displacement. The method of the invention takes the change of the rainfall amount of the landslide as the loading and unloading power parameter of the landslide, takes the displacement or displacement rate change of the landslide as the response parameter of the slide body to the external power change, and determines the rainfall loading and unloading displacement response ratio coupling prediction parameter and the model of the landslide based on the loading and unloading power parameter and the displacement response parameter of the landslide; and determining the corresponding critical rainfall when the side slope is in an unstable state by taking the rainfall plus unloading displacement response ratio coupling power parameter of the landslide as a criterion. The monitoring early-warning rainfall capacity of the landslide is the critical unstable starting rainfall capacity of the landslide, and the determination of the critical landslide starting rainfall capacity can provide effective monitoring early-warning and prevention basis for the monitoring early-warning and prevention of the landslide induced by rainfall.

Description

A kind of Rainfall landslide Instability starts the assay method of rainfall amount

Technical field

The present invention relates to a kind of monitoring mode that uses and determine that Rainfall landslide Instability starts the assay method of rainfall amount, be specifically related to based on rainfall amount and the analysis of real-time displacement monitoring aggregation of data and determine that rainfall induced landslide Instability starts a kind of assay method of rainfall amount.

Background technology

Landslide is destroyed and one of dangerous geologic hazard as tool, and to it, evaluating timely and effectively with preventing and treating is the key of its disaster reduction and prevention.Wherein, select and determine practical and effectively to prevent and treat plans and measures be again the top priority facing in landslide control process.In landslide disaster, rainfall induced landslide occupies larger ratio, and has very strong sudden and huge destructiveness, therefore, how such landslide is is scientificlly and effectively prevented and treated and has very important disaster reduction and prevention meaning and value.A large amount of engineering practices prove, it is the most key early warning and index for control and the parameter of such landslide monitoring early warning and control that the Instability of rainfall induced landslide starts rainfall amount.

The critical startup rainfall amount of determining at present Rainfall landslide generally adopts limit equilibrium method and heuristic methods.Limiting equilibrium evaluation assessment mainly changes rainfall infiltration underground water place value, by the reduction effect of its formed sound water pressure and intensive parameter, be converted into the variation of sliding force and the skid resistance of slope body, and then use the ultimate principle of limit equilibrium method to determine the stability factor coming down.According to the corresponding relation of stability factor and underground water, determine the corresponding critical startup underground water table of safety coefficient Fs coming down in < < Technique Code for Building Slope Engineering > >, finally according to the relation of grade of side slope and Condition of Rainfall Infiltration and rainfall amount and underground water table, release its critical startup rainfall amount.But these class methods have the following disadvantages and limit to: first the method need to sample slope, landslide body, obtains the physical and mechanical parameter of slope body, and needs to measure its underground water table, sets up geologic model and calculates.Because the relation of Landslide Groundwater position and rainfall amount is very complicated and changeable, accurately determine very difficulty of said two devices quantitative relationship.In addition, landslide sampling is a very complex process, especially landslide induced is carried out to underwater sampling more difficult, easily forms collapse hole, and the landslide induced material that native stone mixes is difficult to carry out indoor test, very easily produces test error.Therefore, use said method to determine that the landslide critical startup rainfall amount of unstability exists very large uncertainty.

Heuristic methods is the critical rainfall amount that uses other similar rainfall induced landslides to measure, and on this basis and field experience analogy method determine the critical startup rainfall amount of unstability on to be evaluated and control landslide, as (2012) such as Capparelli G. deliver " Modelling the rainfall-induced mobilization of a large slope movement in northern Calabria " achievement in research at < < Nat Hazards > >.This achievement is basis with the pass between slope displacement and rainfall in early stage, and has set up landslide rainfall forecast model by calibration empirical model, with this, obtains the rainfall amount critical value of induced landslide.But because these class methods determine that foundation is to pass through analogies of experience, often need could estimate by the analysis of the different condition of raining Statistical Comparison of a plurality of landslide engineerings the critical rainfall value of unstability that is applicable to landslide to be evaluated, and the critical rainfall value of this unstability is subject to impact and the control of different landslides geologic condition, therefore there is larger blindness, randomness and uncertainty in these class methods.

In addition, determine that critical startup rainfall amount also has method for numerical simulation.The method is to use finite element or the definite rainfall of finite difference method simulation to bring out safety coefficient and the corresponding critical rainfall amount thereof on type landslide.These class methods determine that critical startup rainfall amount is to be based upon to determine rational constitutive relation and accurately under the explicitly known condition of soil layer physical and mechanical parameter, but because the restriction of sampling and test condition is difficult to obtain Rock And Soil physical and mechanical parameter accurately, be difficult to slope, true reflection landslide body actual conditions, its result is easily subject to above-mentioned factor and finite element software " black box " and human factor impact and produces larger error, and has the limitation problems such as computation process is loaded down with trivial details, calculated amount is large and grow computing time.Therefore, seek a kind of new method that breaks through existing conventional art, seek a kind of new method of critical startup rainfall amount of coming down that there is clear and definite criterion and only use to Landslide Deformation and rainfall amount monitoring just can detect and determine, will in the optimal design of the monitoring and warning at such landslide disaster and mitigation prevention and cure project, there is important using value.

Summary of the invention

The present invention seeks to determine in order to overcome above-mentioned existing classic method deficiency and the defect of the critical startup rainfall amount of rainfall induced landslide, a kind of convenient rapid assay methods of utilizing rainfall amount and displacement monitoring to determine the critical startup rainfall amount of rainfall induced landslide is provided.Concrete invention thinking is the unloading kinetic parameter of adding the variation of landslide rainfall amount as landslide, landslide displacement or rate of displacement are changed to the response parameter changing for outer power as gliding mass, take landslide to add unloading kinetic parameter and displacement response parameter be foundation, determine that the rainfall on landslide adds unloading displacement response ratio coupling Prediction Parameters and model; It is criterion that the rainfall on landslide of take adds unloading displacement response ratio coupling power parameter, determines critical rainfall amount corresponding when non-steady state appears in side slope.

To achieve these goals, the technical solution used in the present invention is: a kind of Rainfall landslide Instability starts the assay method of rainfall amount, mainly comprises the following steps:

The first step: landslide displacement monitoring point is chosen with reference point

To landslide to be determined, the main skating area of analysis of landslide and trailing edge tension fracture, cut the key positions such as mouth, determine the features such as sliding mass size and distribution range, choose monitoring point for displacement and the reference point on landslide;

Second step: the layout of monitoring equipment and installation

Monitoring equipment comprises rainfall amount monitoring equipment and displacement monitoring equipment, and wherein rainfall amount monitoring equipment is laid at slope monitoring point place; Displacement monitoring equipment is at slope body layout of the monitoring points;

The 3rd step: the Real-Time Monitoring of rainfall amount and displacement and Monitoring Data are processed

According to the rainfall on landslide and the Changing Pattern of displacement, determine its monitoring time interval and monitoring mode, with certain hour interval, synchronously with the cycle, the rainfall amount of landslide area and rate of displacement are monitored, and Monitoring Data is transferred to remote monitoring chamber to the Monitoring Data pre-service of classifying by side slope place data-signal gatherer, and typing Excel form in detail;

The 4th step: unit statistical study cycle and average rainfall amount (Q ₀) and mean shift speed (V ₀) determine: according to landslide rainfall change and monitoring time interval, determine unit statistical study and evaluation cycle; According to unit monitoring time interval, can determine that m unit monitoring time (or day or hour etc.) is as the statistical study of Yi Ge unit and evaluation cycle, and with this can determine year or month unit statistical study and evaluation cycle number.In unit statistical study and evaluation cycle, rainfall amount sequence is Q _i(i=1,2 ... n), rate of displacement sequence is V _i(i=1,2 ... n), the average rainfall amount (Q of two sequences ₀) and mean shift speed (V ₀) be:

${\mathrm{<figure-callout\; id="0"\; label="Q"\; filenames="HDA0000411712550000032.png"\; state="\{\{state\}\}">Q</figure-callout>}}_0=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{Q}_i$ (i=1,2 ..., n) formula 1

${\mathrm{<figure-callout\; id="0"\; label="V"\; filenames="HDA0000411712550000032.png"\; state="\{\{state\}\}">V</figure-callout>}}_0=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{V}_i$ (i=1,2 ..., n) formula 2

The 5th step: rainfall amount adds uninstall parms and adds determining of discharging quantity

The rainfall amount sequence Q of unit of account statistical study and evaluation cycle _iwith average rainfall amount Q ₀add unloading sequence of differences,

Δ Q _i=Q _i-Q ₀(i=1,2 ..., n) formula 3

If sequence of differences Δ Q _i> 0, is judged to be the loading Q to landslide ₊; On the contrary, sequence of differences Δ Q _i< 0, is judged to be the unloading Q to landslide _-;

The 6th step: the determining of rate of displacement response parameter and displacement response amount

The landslide displacement speed sequence V of unit of account statistical study and evaluation cycle _iwith mean shift speed (V ₀) add unloading difference in response value sequence,

Δ V _i=V _i-V ₀(i=1,2 ..., n) formula 4

As difference in response value sequence Δ V _i> 0, is judged to be the load deflection response parameter V on landslide ₊; On the contrary, as difference in response value sequence Δ V _i< 0, is judged to be the unloading displacement response parameter V on landslide _-;

The 7th step: landslide displacement speed and rainfall add determining of unloading response ratio parameter and numerical value

In unit statistical study and evaluation cycle respectively to Δ Q _isequence adds unloading positive and negative Data-Statistics get its average, and what can obtain respectively rainfall adds unloading statistic average

with

respectively landslide displacement rate response sequence of differences added the unloading positive and negative Data-Statistics of response and gets average, can obtain respectively rate of displacement response statistic average

with

Take that to add unloading statistic and add unloading response statistic be foundation, can determine that adding of side slope rainfall and rate of displacement unload response ratio parameter:

$\mathrm{LURR}=\frac{X_{+}}{X_{-}}=\left(\frac{{\mathrm{\&Delta;R}}_{+}}{{\mathrm{\&Delta;P}}_{+}}\right)/\left(\frac{{\mathrm{\&Delta;R}}_{-}}{{\mathrm{\&Delta;P}}_{-}}\right)=\left(\frac{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{V+}}}{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{Q+}}}\right)/\left(\frac{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{V-}}}{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{Q-}}}\right)$ Formula 5

Wherein, with

for loading rainfall amount average and unloading rainfall amount average;

with

be respectively load deflection speed average and unloading rate of displacement average;

According to what calculate that gained adds that unloading response ratio, time series draw landslide rainfall and displacement, add unloading response ratio-time curve;

The 8th step: the determining of the critical startup rainfall amount criterion of landslide unstability

According to plasto-elasticity ultimate principle, determine and add the critical startup rainfall amount of unloading response ratio time series criterion:

1) for adding of analysis and detection monitoring point unloads, whether response ratio occurs suddenling change in monitoring time or occurrence tendency increases variation, first adds up and determines that a certain monitoring point adds mean value and the sequence mean square deviation that unloads response ratio:

$\stackrel{\&OverBar;}{\mathrm{LURR}}=\frac{1}{k}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}{\mathrm{LURR}}_i$ Formula 6

$\mathrm{\&sigma;}=\sqrt{\frac{1}{k-1}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}{({\mathrm{LURR}}_i-\stackrel{\&OverBar;}{\mathrm{LURR}})}^2}$ Formula 7

2) slope stability evolutionary process is divided into following four-stage: as judge that side slope is in the stabilization sub stage;

judge that side slope is in the unstable stage, wherein, as

evaluate side slope in the unstable initial stage in stage; If evaluate side slope in the integral slipping stage;

Therefore, landslide can be added to unloading response ratio Time Series Mean and one times of mean square deviation sum criterion as the critical startup rainfall amount that comes down,

$\left[\mathrm{LURR}\right]=\stackrel{\&OverBar;}{\mathrm{LURR}}+\mathrm{\&sigma;}$ Formula 8

Wherein [LURR] is the criterion of the critical startup rainfall amount of landslide unstability,

σ is respectively and adds mean value and the sequence mean square deviation that unloads response ratio;

The 9th step: the determining of the critical startup rainfall amount of landslide unstability

According to landslide rainfall and real-time displacement monitoring add unloading response ratio and mean square deviation Anomaly criterion thereof, determine the critical startup rainfall amount that comes down:

1) if adding of landslide rainfall and real-time displacement monitoring unloads response ratio and is less than or equal to its serial mean and one times of mean square deviation sum, show that now side slope rainfall amount is for normally to stablize rainfall amount, at this rainfall slope in steady state (SS);

2) if the unloading response ratio that adds of landslide rainfall and real-time displacement monitoring is greater than its serial mean and one times of mean square deviation sum, show that now side slope rainfall amount is over normally stablizing rainfall amount, side slope plays pendulum; Show

corresponding rainfall amount causes the critical startup rainfall amount of sliding unstability for side slope.

Described in the first step monitoring point for displacement be selected in side slope main sliding surface slope body, tensile crack or cut port part, and set several monitoring point for displacements.

Described in the first step, displacement monitoring reference point is selected in monitoring stable basement rock or without the region of distortion, formation control net, guarantees that oneself checks and control slope monitoring point comprehensive monitoring beyond sliding mass.

The monitoring and warning rainfall amount on landslide is its Instability and starts rainfall amount, and this critical startup rainfall amount that comes down definite can be rainfall induced landslide monitoring and warning and control provides effective monitoring and warning and evidence for prevention and cure.

The present invention is according to plasto-elasticity ultimate principle, landslide rainfall is added to unloading dynamic action and landslide displacement dynamic response and carried out organic coupling and evaluation, with this, set up the critical startup rainfall amount criterion of landslide unstability, and determined on this basis the critical startup rainfall amount of Rainfall landslide unstability, open up a kind of rainfall and real-time displacement monitoring of using and measured the come down new method of critical startup rainfall amount of unstability of Rainfall.

The ultimate principle of the assay method of Rainfall of the present invention landslide Instability startup rainfall amount is as follows with foundation:

According to plasto-elasticity ultimate principle, the stress and strain of elastic-plastic material is followed following rule: the elastic deformation stage---at straight line OA ₁in the elastic deformation stage of section, after its loading and unloading, deformation energy recovers completely, is out of shape reversiblely, and stress-strain has relation one to one; Plastic period---after unloading, deformation energy partly recovers, and part left behind, i.e. curve A ₁c ₁d ₁for plastic period, feature is that distortion can not recover completely, and strain-stress relation is non-linear and corresponding no longer one by one, relevant with loading history.By elastic-plastic material stress---strain curve is known, at OA ₁elastic stage, loading response amount is identical with unloading response amount with the variation of stress; Enter A ₁c ₁d ₁after plastic period, at A ₁c ₁section, during loading, stress increases σ ₂-σ ₁, strain variation amount is ε ₃-ε ₁; During unloading, stress reduces σ ₂-σ ₁, dependent variable is changed to ε ₃-ε ₂, obviously strain-responsive amount corresponding to load phase is large.The stress and strain rule of above-mentioned material shows, along with the increase of material plasticity instability distortion, the difference of its corresponding strain-responsive amount of loading and unloading stage is also increasing.

From Fig. 2 elastic-plastic material stress-strain curve, at OA ₁elastic stage, loads and unloading phase is followed identical deformation rule, and material enters after mecystasis A1 point, in loading and unloading phase, will follow different deformation rules.In the elastic deformation stage, material is observed linear elasticity Hooke's law, and its deformation modulus is identical with initial modulus; At plastic period,, the plastic yield of material production nonlinear elasticity, no longer observes linear elasticity Hooke's law, and its deformation modulus reduces the increase along with the distortion of material plasticity instability, but the difference of the corresponding strain-responsive amount of loading and unloading is increasing.

According to the basic deformation rule of above-mentioned material, can, by system before nonlinear system unstability to loading responsiveness and the ratio that unloads responsiveness, add unloading response ratio LURR, as the quantitative parameter of nonlinear system estimation of stability, $\mathrm{LURR}=\frac{X_{+}}{X_{-}}=\left(\frac{{\mathrm{\&Delta;R}}_{+}}{{\mathrm{\&Delta;P}}_{+}}\right)/\left(\frac{{\mathrm{\&Delta;R}}_{-}}{{\mathrm{\&Delta;P}}_{-}}\right)=\left(\frac{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{V+}}}{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{Q+}}}\right)/\left(\frac{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{V-}}}{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{Q-}}}\right),$ Wherein, Δ R ₊with Δ R _-be respectively and load response increment and unloading response increment; Δ P ₊with Δ P _-be respectively and load increment and unloading increment;

for responsiveness.Make X ₊with X _-represent respectively the responsiveness of loading and unloading, when load is very little, system, in steady state (SS), is at this moment linearity or linear approximate relationship between P and R, in this stage, and responsiveness X during loading ₊responsiveness X during with unloading _-substantially equal; If load constantly increases, move closer to critical value P _crbe system while being tending towards unstable, its responsiveness increases and constantly increases with load; When system unstability, X ₊→ ∞.This explanation, when approaching unstability, even extremely small loading all can cause the huge response of system.Therefore, a nonlinear system is loaded, even if load increment remains unchanged, because the stability status of system is different, its responsiveness is also different, and displacement response is larger, and system is more unstable, therefore, for elastic system, X ₊=X _-=C, so LURR=1; But for nonlinear system, LURR value is relevant with system stability state.When system is during in steady state (SS), LURR=1; When system departs from stable state, LURR>1; When system unstability, LURR → ∞.Therefore, the nonlinear system at quarter that LURR value can be quantitative departs from the degree of stable state (or approaching unstability), also can be used as the criterion of nonlinear system unstability forecast.

According to above-mentioned plasto-elasticity ultimate principle, when coming down in elastic deformation steady state (SS), its load deflection response amount equates with unloading displacement response amount; When landslide enters plastic yield during the unstable stage, its load deflection response amount will be greater than unloading displacement response amount, and load deflection response amount increases along with the reduction of slope stability gradually with the difference of unloading displacement response amount; When coming down in whole unstable failure, its displacement load deflection response will be tending towards infinitely great, and unloading displacement response is constant,, when LURR=1, shows that side slope is in steady state (SS); When LURR > 1, show that slope system departs from stable state, play pendulum; When LURR occurs suddenling change and is tending towards infinitely great, show that landslide is about to whole unstability.Therefore, according to above-mentioned ultimate principle, can be using rainfall amount and rainfall increment as landslide being added to the means of unloading; According to the moon rainfall amount discrimination standard that adds unloading with difference or month positive and negative conduct of rainfall increment of average annual rainfall amount, and divide rainfall adding between unload zone for landslide effect with this; And add the slope displacement speed in when unloading or displacement acceleration be elected to be slope body to outside loads change add unloading response, with this, determine that Rainfall landslide rainfall amount and adding of displacement unload response ratio and unstability starts critical rainfall amount.

Accompanying drawing explanation

The steps flow chart schematic diagram of Fig. 1 the inventive method;

Fig. 2 elastic-plastic material stress-strain curves;

Fig. 3 landslide monitoring point is arranged schematic diagram, and wherein 01 is sliding mass, and 02 is rate of displacement monitoring point, and 03 is sliding mass shearing tensile crack; P is displacement monitoring reference point;

Fig. 4 is certain landslide and monitoring point schematic diagram thereof in embodiment, and wherein 04 is glide plane, the 05 slope body that is main sliding surface, and 06 is basement rock, and 07 is rainfall, and 08 is tensile crack position, and 09 for cutting port part;

Fig. 5 is that in embodiment, certain landslide E3 point adds unloading response ratio curve, the intersection point that adds unloading response ratio curve and catastrophic criterion line that wherein A, B point is E3 place, monitoring point;

Fig. 6 is that in embodiment, certain landslide E4 point adds unloading response ratio curve, the intersection point that adds unloading response ratio curve and catastrophic criterion line that wherein C point is E4 place, monitoring point;

Fig. 7 be in embodiment certain E3 point place, landslide before in Dec, 84,85 years 6 month add unloading response ratio curve and Anomaly criterion line, B point is monitoring point E3 point place adds the intersection point that unloads response ratio curve and Anomaly criterion line;

Fig. 8 be in embodiment certain E4 point place, landslide before in Dec, 84,85 years 6 month add unloading response ratio curve and Anomaly criterion line, C point is monitoring point E4 point place adds the intersection point that unloads response ratio curve and Anomaly criterion line.

Embodiment

In order to set forth better the present invention, below in conjunction with accompanying drawing, take certain rainfall induced landslide to be elaborated as the assay method that example starts rainfall amount to Rainfall of the present invention landslide Instability.This landslide is landslide induced along the Yangtze River, and this comes down unstable failure occurred in June, 1985.The monitoring time on the present embodiment landslide is year June in January, 1978 to 1985.Take this landslide as example, and as shown in Figure 1, concrete implementation step is as follows for method step flow process of the present invention:

The first step: landslide displacement monitoring point is chosen with reference point

The corresponding domatic layout monitoring point, main skating area of choosing monitor landslide, arranges two monitoring point E3, E4 according to the main sliding surface of landslide main skating area west side leading edge and toe, in the unexpected region without distortion of detection sliding mass, arranges displacement monitoring reference point P, sees Fig. 3, Fig. 4.

Second step: the layout of monitoring equipment and installation

At E3,2 of E4, arrange that respectively commercially available NOMAD Portable weather station and wireless system for monitoring displacement monitor respectively rainfall amount and slope displacement speed.Combine closely in the monitoring equipment that assurance is buried underground and sliding mass top layer, separate between equipment, non-interference, and each monitoring point displacement changing value is effectively monitored.

The 3rd step: the Real-Time Monitoring of rainfall amount and displacement and Monitoring Data are processed

Take the moon as the time interval synchronously collects rate of displacement and the rainfall amount Monitoring Data on landslide by landslide place data-signal gatherer with the cycle, and be transferred to remote monitoring chamber, in monitoring chamber, every January, with Excel process software, carry out the pre-service of Monitoring Data, obtain rainfall amount (in Table 1) and landslide displacement rate value (in Table 2～3).

Table 1 landslide area moon rainfall data (unit is mm)

Certain landslide E3 point month rate of displacement (unit is mm) of table 2

Certain landslide E4 point month rate of displacement (unit is mm) of table 3

The 4th step: unit statistical study cycle and average rainfall amount (Q ₀) and mean shift speed (V ₀) determine:

According to unit monitoring time interval, determine one month as the statistical study of Yi Ge unit and evaluation cycle, annual average rainfall amount (Q in the corresponding monitoring time section of side slope rainfall sequence and rate of displacement sequence ₀) and rate of displacement average (V ₀) can be in Table 4～6.

Annual average rainfall amount Q in table 4 monitoring time section ₀

Annual mean shift speed V in certain landslide E3 point monitoring time section of table 5 ₀

Annual mean shift speed V in certain landslide E4 point monitoring time section of table 6 ₀

The 5th step: rainfall amount adds uninstall parms and adds determining of discharging quantity

Utilize formula Δ Q _i=Q _i-Q ₀calculate and to add unloading sequence of differences in the annual monitoring time section of rainfall, in Table 7.

The 6th step: the determining of rate of displacement response parameter and displacement response amount

Utilize formula Δ V _i=V _i-V ₀calculate the displacement difference in response value sequence in annual each monitoring time section, in Table 8～9.

In the annual monitoring time section of table 7 rainfall, add unloading sequence of differences

Note: sequence of differences Δ Q _i> 0, is defined as side slope is loaded to Q ₊; On the contrary, sequence of differences Δ Q _i< 0, is defined as side slope unloading Q _-;

Adding in the annual monitoring time section of table 8E3 point, unloads displacement difference in response value sequence Δ V _i

Adding in the annual monitoring time section of table 9E4 point, unloads displacement difference in response value sequence Δ V _i

Note: difference in response value sequence Δ V _i> 0, is defined as side slope and loads response V ₊; On the contrary, difference in response value sequence Δ V _i< 0, is defined as side slope unloading response V _-.

The 7th step: landslide displacement speed and rainfall add determining of unloading response ratio parameter and numerical value

That utilizes that form 7～9 in five～six steps can obtain respectively rainfall amount adds unloading statistic average

with

with rate of displacement response statistic average

with in Table 10.

Adding of table 10 rainfall and rate of displacement response unloads statistic average statistical form

Note: add uninstall parms unit: mm; Displacement response parameter unit: mm/.

By the E4 that comes down in table 10, E3 point

sequence is substitution formula respectively:

$\mathrm{LURR}=\frac{X_{+}}{X_{-}}=\left(\frac{{\mathrm{\&Delta;R}}_{+}}{{\mathrm{\&Delta;P}}_{+}}\right)/\left(\frac{{\mathrm{\&Delta;R}}_{-}}{{\mathrm{\&Delta;P}}_{-}}\right)=\left(\frac{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{V+}}}{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{Q+}}}\right)/\left(\frac{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{V-}}}{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{Q-}}}\right)$ (formula 5)

Obtaining coming down, E3, E4 order adds unloading response ratio time series, in Table 11～12.

Certain landslide E3 point of table 11 adds unloading response ratio-time series

What certain landslide E4 of table 12 was ordered adds unloading response ratio---time series

According to what calculate that gained adds that unloading response ratio-time series draws landslide rainfall and displacement, add unloading response ratio-time curve, see Fig. 5, Fig. 6.

The 8th step: the determining of the critical startup rainfall amount criterion of landslide unstability

According to plasto-elasticity ultimate principle, when coming down in elastic deformation steady state (SS), its load deflection response amount equates with unloading displacement response amount; When landslide enters plastic yield during the unstable stage, its load deflection response amount will be greater than unloading displacement response amount, and load deflection response amount increases along with the reduction of slope stability gradually with the difference of unloading displacement response amount; When coming down in whole unstable failure, its displacement load deflection response will be tending towards infinitely great, and unloading displacement response is constant.Therefore,, according to above-mentioned ultimate principle, when LURR=1, show that side slope is in steady state (SS); When LURR > 1, show that slope system departs from stable state, play pendulum; When LURR occurs suddenling change and is tending towards infinitely great, show that landslide is about to whole unstability.Therefore, can, according to above-mentioned slope stability criterion, determine that the unstability of rainfall induced landslide starts critical rainfall amount.Its determining step that adds the critical startup rainfall amount of unloading response ratio time series criterion is as follows:

1) for adding of analysis and detection monitoring point unloads, whether response ratio occurs suddenling change in monitoring time or occurrence tendency increases variation, first adds up and determines that a certain monitoring point adds mean value and the sequence mean square deviation that unloads response ratio:

$\stackrel{\&OverBar;}{\mathrm{LURR}}=\frac{1}{k}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}{\mathrm{LURR}}_i$ (formula 6)

$\mathrm{\&sigma;}=\sqrt{\frac{1}{k-1}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}{({\mathrm{LURR}}_i-\stackrel{\&OverBar;}{\mathrm{LURR}})}^2}$ (formula 7)

2), according to statistical principle, landslide is added to unloading response ratio Time Series Mean and 2 times of mean square deviation sums criterion as the critical startup rainfall amount of unstability that comes down,

$\left[\mathrm{LURR}\right]=\stackrel{\&OverBar;}{\mathrm{LURR}}+\mathrm{\&sigma;}$ (formula 8)

Result of calculation is in Table 13.Draw Anomaly criterion curve, see Fig. 7, Fig. 8.

Table 13E3,2 of E4 add unloading response ratio time series mean value and response ratio mean square deviation

The 9th step: the determining of the critical startup rainfall amount of landslide unstability

According to landslide rainfall and real-time displacement monitoring add unloading response ratio and mean square deviation Anomaly criterion thereof, determine the critical startup rainfall amount that comes down:

1) if adding of landslide rainfall and real-time displacement monitoring unloads response ratio and is less than or equal to its serial mean and one times of mean square deviation sum, show that now side slope rainfall amount is for normally to stablize rainfall amount, at this rainfall slope in steady state (SS);

2) if the unloading response ratio that adds of landslide rainfall and real-time displacement monitoring is greater than its serial mean and one times of mean square deviation sum, show that now side slope rainfall amount is over normally stablizing rainfall amount, side slope plays pendulum; Show that now rainfall amount is the critical startup rainfall amount that side slope causes sliding unstability.

The monitor value of rainfall amount is from Fig. 7,8, and what A, B point was E3 place, monitoring point adds unloading response ratio curve and add the intersection point that unloads response ratio Anomaly criterion line; What C point was E4 place, monitoring point adds unloading response ratio curve and adds the intersection point that unloads response ratio Anomaly criterion line.Except A, B, the LURR of C point the corresponding time, all take and 1 fluctuate up and down as reference point, side slope is in the stabilization sub stage; The LURR of A, B, C corresponding time of point all meets

slope instability, because A point is steady state (SS) to side slope between C point, can judge that the corresponding time of B, C point, side slope was in the unstability stage afterwards, this and actual slope instability time match, therefore, the corresponding average rainfall of available B, C point is as the unsettled startup rainfall amount in landslide.According to adding unloading response ratio mean square deviation Anomaly criterion, can determine 85 years 3, the average rainfall in April, the critical startup rainfall amount that the mean value 47.85mm of 16.6mm and 79.1mm is this landslide.

Claims (3)

1. Rainfall landslide Instability starts an assay method for rainfall amount, comprises the following steps: the first step: landslide displacement monitoring point is chosen with reference point

To landslide to be determined, the main skating area of analysis of landslide and trailing edge tension fracture, cut the key positions such as mouth, determine the features such as sliding mass size and distribution range, choose monitoring point for displacement and the reference point on landslide;

Second step: the layout of monitoring equipment and installation

Monitoring equipment comprises rainfall amount monitoring equipment and displacement monitoring equipment, and wherein rainfall amount monitoring equipment is laid at slope monitoring point place; Displacement monitoring equipment is at slope body layout of the monitoring points;

The 3rd step: the Real-Time Monitoring of rainfall amount and displacement and Monitoring Data are processed

According to the rainfall on landslide and the Changing Pattern of displacement, determine its monitoring time interval and monitoring mode, with certain hour interval, synchronously with the cycle, the rainfall amount of landslide area and rate of displacement are monitored, and Monitoring Data is transferred to remote monitoring chamber to the Monitoring Data pre-service of classifying by side slope place data-signal gatherer, and typing Excel form in detail;

The 4th step: unit statistical study cycle and average rainfall amount (Q ₀) and mean shift speed (V ₀) determine: according to landslide rainfall change and monitoring time interval, determine unit statistical study and evaluation cycle; According to unit monitoring time interval, can determine that m unit monitoring time is as the statistical study of Yi Ge unit and evaluation cycle, and can determine unit statistical study and the evaluation cycle number of year or the moon with this.In unit statistical study and evaluation cycle, rainfall amount sequence is Q _i(i=1,2 ... n), rate of displacement sequence is V _i(i=1,2 ... n), the average rainfall amount (Q of two sequences ₀) and mean shift speed (V ₀) be:

$Q_0=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{Q}_i$ (i=1,2 ..., n) formula 1

$V_0=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{V}_i$ (i=1,2 ..., n) formula 2

The 5th step: rainfall amount adds uninstall parms and adds determining of discharging quantity

The rainfall amount sequence Q of unit of account statistical study and evaluation cycle _iwith average rainfall amount Q ₀add unloading sequence of differences,

Δ Q _i=Q _i-Q ₀(i=1,2 ..., n) formula 3

If sequence of differences Δ Q _i> 0, is judged to be the loading Q to landslide ₊; On the contrary, sequence of differences Δ Q _i< 0, is judged to be the unloading Q to landslide _-;

The 6th step: the determining of rate of displacement response parameter and displacement response amount

The landslide displacement speed sequence V of unit of account statistical study and evaluation cycle _iwith mean shift speed (V ₀) add unloading difference in response value sequence,

Δ V _i=V _i-V ₀(i=1,2 ..., n) formula 4

As difference in response value sequence Δ V _i> 0, is judged to be the load deflection response parameter V on landslide ₊; On the contrary, as difference in response value sequence Δ V _i< 0, is judged to be the unloading displacement response parameter V on landslide _-;

The 7th step: landslide displacement speed and rainfall add determining of unloading response ratio parameter and numerical value

In unit statistical study and evaluation cycle respectively to Δ Q _isequence adds unloading positive and negative Data-Statistics get its average, and what can obtain respectively rainfall adds unloading statistic average

with

respectively landslide displacement rate response sequence of differences added the unloading positive and negative Data-Statistics of response and gets average, can obtain respectively rate of displacement response statistic average with

Take that to add unloading statistic and add unloading response statistic be foundation, can determine that adding of side slope rainfall and rate of displacement unload response ratio parameter:

$\mathrm{LURR}=\frac{X_{+}}{X_{-}}=\left(\frac{{\mathrm{\&Delta;R}}_{+}}{{\mathrm{\&Delta;P}}_{+}}\right)/\left(\frac{{\mathrm{\&Delta;R}}_{-}}{{\mathrm{\&Delta;P}}_{-}}\right)=\left(\frac{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{V+}}}{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{Q+}}}\right)/\left(\frac{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{V-}}}{\stackrel{\&OverBar;}{{\mathrm{\&sigma;}}_{Q-}}}\right)$ Formula 5

Wherein,

with

for loading rainfall amount average and unloading rainfall amount average;

with

be respectively load deflection speed average and unloading rate of displacement average;

According to what calculate that gained adds that unloading response ratio, time series draw landslide rainfall and displacement, add unloading response ratio-time curve;

The 8th step: the determining of the critical startup rainfall amount criterion of landslide unstability

According to plasto-elasticity ultimate principle, determine and add the critical startup rainfall amount of unloading response ratio time series criterion:

1) for adding of analysis and detection monitoring point unloads, whether response ratio occurs suddenling change in monitoring time or occurrence tendency increases variation, first adds up and determines that a certain monitoring point adds mean value and the sequence mean square deviation that unloads response ratio:

$\stackrel{\&OverBar;}{\mathrm{LURR}}=\frac{1}{k}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}{\mathrm{LURR}}_i$ Formula 6

$\mathrm{\&sigma;}=\sqrt{\frac{1}{k-1}\underset{i=1}{\overset{k}{\mathrm{\&Sigma;}}}{({\mathrm{LURR}}_i-\stackrel{\&OverBar;}{\mathrm{LURR}})}^2}$ Formula 7

2) slope stability evolutionary process is divided into following four-stage: as

judge that side slope is in the stabilization sub stage; judge that side slope is in the unstable stage, wherein, as

evaluate side slope in the unstable initial stage in stage; If evaluate side slope in the integral slipping stage;

Therefore, landslide can be added to unloading response ratio Time Series Mean and one times of mean square deviation sum criterion as the critical startup rainfall amount that comes down,

$\left[\mathrm{LURR}\right]=\stackrel{\&OverBar;}{\mathrm{LURR}}+\mathrm{\&sigma;}$ Formula 8

Wherein [LURR] is the criterion of the critical startup rainfall amount of landslide unstability,

σ is respectively and adds mean value and the sequence mean square deviation that unloads response ratio;

The 9th step: the determining of the critical startup rainfall amount of landslide unstability

According to landslide rainfall and real-time displacement monitoring add unloading response ratio and mean square deviation Anomaly criterion thereof, determine the critical startup rainfall amount that comes down:

1) if adding of landslide rainfall and real-time displacement monitoring unloads response ratio and is less than or equal to its serial mean and one times of mean square deviation sum, show that now side slope rainfall amount is for normally to stablize rainfall amount, at this rainfall slope in steady state (SS);

2) if the unloading response ratio that adds of landslide rainfall and real-time displacement monitoring is greater than its serial mean and one times of mean square deviation sum, show that now side slope rainfall amount is over normally stablizing rainfall amount, side slope plays pendulum; Show

corresponding rainfall amount causes the critical startup rainfall amount of sliding unstability for side slope.

2. Rainfall according to claim 1 landslide Instability starts the assay method of rainfall amount, it is characterized in that: described in the first step monitoring point for displacement be selected in side slope main sliding surface slope body, tensile crack or cut port part, and set several monitoring point for displacements.

3. Rainfall according to claim 1 landslide Instability starts the assay method of rainfall amount, it is characterized in that: described in the first step, displacement monitoring reference point is selected in monitoring stable basement rock or without the region of distortion beyond sliding mass, formation control net, guarantees that oneself checks and control slope monitoring point comprehensive monitoring.

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