CN102561295A - Method for observing and calculating depth of newly-generated swelling shrinking deformation of excavation expansive soil slope surface - Google Patents

Abstract

The invention discloses a method for observing and calculating depth of newly-generated swelling shrinking deformation of an excavation expansive soil slope surface. The method comprises the following steps of: carrying tracking observation by embedding a displacement meter in a shallow shaft, carrying out time effect statistic analysis on an observation result based on assumption of linear attenuation of the swelling shrinking deformation along the depth of the slope surface, and calculating the depth of the swelling shrinking deformation of a slop surface soil body under the action of weather by utilizing a linear equation on the premise of reasonable linear assumption verified by observation data. The method for observing and calculating the depth of the newly-generated swelling shrinking deformation of the excavation expansive soil slope surface, disclosed by the invention, overcomes difficulty that a fixed point is hard to exactly arrange by a surface mark measurement method, also has the advantages of high precision of the observation data and small influence by personal factors compared with the surface mark measurement method, and is reasonable in calculating method and simple and convenient to calculation; and analysis parameters of a protection design matching conditions of local weather can be provided for a protective barrier of the excavation expansive soil slop surface through the results obtained by the observation and the calculation according to the method disclosed by the invention.

Description

The observation and the computational methods of the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope

Technical field

The present invention relates to a kind of means of defence of highway expansive soil slope, particularly relate to a kind of observation and computational methods of excavating the domatic newborn swell-shrinking deformation degree of depth of expansive soil slope.

Background technology

Expansive soil is a kind ofly to contain montmorillonite mineral and have the special soil that bad engineering properties is shunk in imbibition, dehydration.The excavation effect with the domatic soil body of expansive soil slope by excavation before the soil body in residing comparatively deep become the top layer soil body; Under the weather alternation of wetting and drying effect of near surface; Soil body water content changes; Thereby cause that the domatic swell-shrinking deformation of excavation expansive soil slope is movable, form the domatic newborn swell-shrinking deformation active belt of excavation and bring out the domatic craze and transfiguration of expansive soil excavation slope, the domatic destruction such as collapse of slipping.For this reason, need accurately to measure the domatic newborn swell-shrinking deformation degree of depth of excavation, so that select suitable preventive works measure that the domatic expansive soil soil body of this depth bounds is protected.Existing method generally adopts high accuracy transit and level gauge to carry out long-term face of land tracking measurement and confirm the domatic newborn swell-shrinking deformation degree of depth of excavation through fixed point, domatic observation point and deep layer observation point are set.Because also there is the swell-shrinking deformation active belt in top layer, the face of land, the swelled ground area non-excavation place nature soil body, the fixed point that observation is set is very difficult, so this method is difficult to accurately observe the domatic newborn swell-shrinking deformation of excavation.For want of excavate at present the accurate observation and the computational methods of the domatic newborn swell-shrinking deformation active belt degree of depth, usually still (like skeleton+grass planting protection, general defense-in-depth is at 0.5m～1.0m) by conventional defense-in-depth design in the preventive works design of excavation expansive soil slope.In fact, excavate the domatic newborn swell-shrinking deformation degree of depth between 1.11m～2.47m, this explanation defense-in-depth is shallow excessively to be to cause adopting conventional slope protection engineering to carry out the main cause that the protection of expansive soil excavation slope was generally lost efficacy.

Summary of the invention

Technical problem to be solved by this invention provides a kind of observation and the computational methods that can accurately observe the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope of the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope.

In order to solve the problems of the technologies described above, the observation and the computational methods of the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope provided by the invention, concrete observation and analytical procedure are following:

(1), selects displacement meter;

(2), make displacement meter and bury installation accessories underground: bury installation accessories underground and must be able to guarantee that displacement meter does not receive the influence of soil pressure, can guarantee to observe the small deflection of the soil body of scale range again;

(3), excavation observation shallow well: respectively dig an observation shallow well at domatic each layer soil body of excavation;

(4), displacement meter is installed: select to solve the vertical observation problem of line swell-shrinking deformation amount relatively of slope table 0mm-500mm analysis layer with two displacement meters; Promptly lay first displacement meter by parallel line of slope in 0mm～200mm degree of depth; The line swell-shrinking deformation rate of supposing 0mm～200mm soil layer has isotropism; The line swell-shrinking deformation discharge observation result of parallel line of slope is converted to the observed result of vertical direction through converting; Second displacement meter then is arranged in 200mm～500mm depth layer by vertical direction; Both observed result additions have just been obtained the vertical line swell-shrinking deformation amount relatively same period of 0mm～500mm analysis layer, and the 3rd displacement meter is by be embedded in 500mm～1000mm analysis layer by vertical direction; To observe location-plate be contained on the installing and locating bar earlier during the burying underground of concrete displacement meter; And fix with installing and locating bar steady pin; To observe location-plate squeeze in the soil of observed length scope again; Take out the installing and locating bar then, the sensor spacer bar is enclosed within middle part above the steel device for carrying a tripot formula displacement meter, and be fixed on the observation location-plate.

(5), confirming of observation frequency, basic statistics period and climatic effect statistics phase: through analyzing main weather effect key element amount of precipitation, the evaporation capacity basic statistics period that Feature Selection is suitable over time and climatic effect statistics phase, observation frequency is more than 2～3 times in the basic statistics period; During concrete the statistics, the observation of climatic effect being added up the first basic statistics period in dry season phase or rainy season is a null value;

(6), relative line breathing of basic statistics period amount is calculated: by formula (1); Calculate the relative line breathing amount λ ti of each observation; By formula (2), calculate the mean of dekan relative line breathing amount

again

$\mathrm{\λti}=\frac{(\mathrm{\λt}-\mathrm{\λ}{i}_0)}{{\mathrm{\λ}}_0}\×L---\left(1\right)$

In the formula: λ i ₀-displacement meter initial reading; l _t--the t time displacement meter reading; λ ₀--actual observation length;

L-represents observation and analysis thickness, and vertical direction is respectively 200mm, 300mm, 500mm.

${\mathrm{\λ}}_{10j}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{\λti}---\left(2\right)$

In the formula: i=1,2,3 ... N-is the observation frequency of this basic statistics period interior lines breathing amount;

(7), the vertical line breathing amount relatively of 0mm～500mm degree of depth soil layer calculates: represent the deflection of sloping top layer 0mm～200mm degree of depth soil layer vertical direction with the deflection of 0mm～parallel line of slope of 200mm degree of depth soil layer, through observing the addition of arrangement value can obtain the deflection of vertical 0mm～500mm degree of depth soil layer vertical direction the domatic top layer 0mm～200mm of the excavation slope same period and two depth layer displacement meters of 200mm～500mm;

(8), the linear attenuation supposition check of average vertical line breathing amount relatively of basic statistics period: divide dry season and rainy season to obtain the average vertical temporal evolution linear equation of line breathing amount relatively of basic statistics period of respectively observing 0cm in the shallow well～50cm degree of depth, 50cm～two observation of 100cm degree of depth soil layer by linear attenuation supposition match, with discriminant coefficient greater than 0.8 as supposing the standard of analyzing by linear attenuation;

(9), the establishment of the climate effects of statistical average of the relative linear expansion shrinkage variation with depth of linear equations: press the formula (3) is calculated with 0.5m and 1.0m depth statistical climatic effects of shrinkage of the relative linear expansion average

and then by a two-point list of the climatic effects of statistical observation wells relative linear expansion of the average shrinkage variation with depth of linear equations (4);

$\stackrel{\‾}{{\mathrm{\λ}}_d}=\frac{1}{t}\underset{j=1}{\overset{t}{\mathrm{\Σ}}}{\mathrm{\λ}}_{10j}---\left(3\right)$

In the formula: j=1,2,3 ... Hop count when t-is the basic statistics in the phase of climatic effect statistics, d is two observation and analysis layer depth (m) .d ₁=0.5m, d ₂=1.0m.

$\mathrm{\&lambda;}=\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}1}}}{d_2-d_1}d+{\mathrm{\&lambda;}}_{d1}-\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}1}}}{d_2-d_1}{d}_1---\left(4\right)$

In the formula: λ is the newborn vertical line breathing amount relatively of excavation expansive soil slope, and d is apart from the excavation domatic degree of depth (m)

Order $k=\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}1}}}{d_2-{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}}_1},$ $b={\mathrm{\&lambda;}}_{d1}-\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}1}}}{d_2-d_1}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}}_1$ Substitution (4):

λ＝kd+b (5)

(10), ask the domatic newborn swell-shrinking deformation degree of depth of expansive soil excavation: according to linear equation (5); The newborn vertical line breathing amount relatively of order excavation expansive soil slope is zero; Be λ=0, try to achieve that corresponding degree of depth formula (6) is the newborn swell-shrinking deformation degree of depth of being asked when being zero with newborn swell-shrinking deformation

$d=-\frac{b}{k}---\left(6\right).$

Selection displacement meter described in the above-mentioned steps (1): getting 500mm is the bed thickness that change in depth is analyzed, and the measurement category of displacement meter is 400mm ± 40mm, and precision is 0.01mm.

Steel device for carrying a tripot formula displacement meter is counted in displacement described in the above-mentioned steps (1).

Displacement meter described in the above-mentioned steps (2) bury underground installation accessories by observation location-plate (1), installing and locating bar (2), installing and locating bar steady pin (3) and sensor spacer bar (4) totally 4 parts form; To observe location-plate (11) be contained on the installing and locating bar (12) during installation earlier; And it is fixing with installing and locating bar steady pin (13); Squeeze in the soil of observed length scope (Fig. 2); Take out installing and locating bar (12) then, sensor spacer bar (14) is enclosed within middle part above the steel device for carrying a tripot formula displacement meter, and be fixed in observation location-plate (11) upward (Fig. 3).

Excavation observation shallow well described in the above-mentioned steps (3): respectively dig an observation shallow well that is of a size of 1m * 1m * 1m at domatic each layer soil body of excavation.

Adopt the observation and the computational methods of the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope of technique scheme; Carry out tracking observation through bury displacement meter underground at shallow well; And with the supposition of the domatic degree of depth linear attenuation observed result is carried out the time effect statistical analysis based on swell-shrinking deformation; Under the rational prerequisite of observation data checking linearity assumption; Ask for the side slope surface soil body swell-shrinking deformation degree of depth under the weather effect with linear equation; Observation procedure provided by the invention has overcome the difficulty that face of land punctuate measuring method is difficult to accurately be provided with fixed point, also has the advantage that observation data precision than face of land punctuate measuring method is high, influenced by human factor to lack, and the computational methods that provided are reasonable; Calculate easyly, the result who observes and calculate by the present invention can provide the protection analysis of design that meets local climate condition parameter for excavation expansive soil slope slope protection.

In sum, the present invention is a kind of observation and the computational methods that can accurately observe the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope of the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope.

Description of drawings

Fig. 1 is that displacement meter is buried the accessory-mount structure sketch map underground.

Fig. 2 is that displacement meter is buried installation accessories underground and buried sketch map underground.

Fig. 3 is that displacement meter is buried underground to install and buried sketch map underground

Fig. 4 is that Ningming excavation expansive soil slope observation shallow well is arranged sketch map.

Fig. 5 is a displacement meter installation site sketch map in the observation shallow well.

Fig. 6 is that the Ningming is the amount of precipitation and the evaporation capacity variation diagram of base unit with the ten days.

Fig. 7 is a Ningming expansive soil linear attenuation supposition suitability discriminant analysis instance graph.

The specific embodiment

Below in conjunction with the accompanying drawing and the specific embodiment the present invention is described further.

For a concrete expansive soil slope soil body observation point, it is constant basically that soil body mineralogical composition and soil body microstructure etc. influences the internal factor of expansive soil swell-shrinking deformation, and the swell-shrinking deformation of expansive soil is main relevant with the amplitude of variation of soil body water content; Suppose both relations in direct ratio; And that the amplitude of variation of slope table layer soil body water content and weather are done wet amplitude of variation is proportional, again since weather do wet amplitude of variation to the effect of slope soil with the depth attenuation, suppose both relations also in direct ratio; Therefore can infer; Same domatic position, the vertical line swell-shrinking deformation amount relatively of the different depth soil body that the cycle observation of different weather drying and watering cycles obtains also should be directly proportional with the degree of depth, in view of the above; Just can carry out the time effect analysis with the supposition of the linear decay of the degree of depth through vertical line swell-shrinking deformation amount relatively; And press the objectivity that the Application of Statistic Methods observation data is differentiated the linear attenuation supposition, for the observation data with linear attenuation rule, available two point form is listed linear equation; Obtain the degree of depth corresponding when vertically line swell-shrinking deformation amount is zero relatively at last, this degree of depth is expansive soil and excavates the domatic newborn swell-shrinking deformation degree of depth.Now, will specifically observe being presented below with analytical procedure in conjunction with the observation instance:

(1), displacement meter is selected: getting 500mm is the bed thickness that change in depth is analyzed, and the measurement category of displacement meter is 400mm ± 40mm, and precision is 0.01mm, is advisable with the profound formula displacement meter of steel;

(2), make displacement meter and bury installation accessories underground: bury installation accessories underground and must be able to guarantee that sensor does not receive the influence of soil pressure, can guarantee to observe the small deflection of the soil body of scale range again.Referring to Fig. 1; The displacement meter that for this reason need make bury underground installation accessories by observation location-plate 11, installing and locating bar 12, installing and locating bar steady pin 13 and sensor spacer bar 14 totally 4 parts form, referring to Fig. 2, will observe location-plate 11 be contained on the installing and locating bar 12 during installation earlier; And it is fixing with installing and locating bar steady pin 13; Squeeze in the soil of observed length scope,, take out installing and locating bar 12 then referring to Fig. 3; Sensor spacer bar 14 is enclosed within middle part above the steel device for carrying a tripot formula displacement meter, and is fixed on the observation location-plate 11.

(3), excavation observation shallow well: referring to Fig. 4; Excavation domatic 2 the A layer expansion soil body 3, the B layer expansion soil body 4, severely-weathered rock stratum 5 and weak weathered stratum 6 respectively dig one be of a size of first of 1m * 1m * 1m and observe shallow well 7, second and observe shallow well the 8, the 3rd and observe shallow well 9 and the 4th to observe shallow well 10,1 expression excavations before natural slope domatic;

(4), displacement meter installs: directly table 0mm-500mm deep vertical direction is installed displacement meter and is observed its vertical line swell-shrinking deformation amount relatively have two problems on the slope: the one, can't be near 0mm mounting plate; If moreover fixed head is installed in below the 100mm depth bounds, have the thick above topsoil of 100mm can not include observation scope in again, fail to observe also because of the swell-shrinking deformation of this part soil body and can bring excessive error.Therefore, select to solve the vertical observation problem of line swell-shrinking deformation amount relatively of slope table 0mm-500mm analysis layer with two displacement meters.Referring to Fig. 5; Promptly lay first displacement meter 15 by parallel line of slope in the 0mm-200mm degree of depth; The line swell-shrinking deformation rate of supposing the 0mm-200mm soil layer has isotropism; The line swell-shrinking deformation discharge observation result of parallel line of slope is converted to the observed result of vertical direction through converting, 17 of second displacement meters are arranged in 200mm～500mm depth layer by vertical direction, both observed result additions have just been obtained the vertical line swell-shrinking deformation amount relatively same period of 0mm～500mm analysis layer.Because the displacement meter gained observed result that table 0mm～200mm depth level direction is laid on the slope is the swell-shrinking deformation of horizontal direction in essence; With the line swell-shrinking deformation amount of vertical direction can there is some difference; But strong rapidly because of slope table soil body weather response, both errors are little.Triple motion meter 16 is by be embedded in 500mm～1000mm analysis layer by vertical direction.Field-mounted process necessarily is noted that when finishing observation wall and squeezes into when observing location-plate and try not the soil body is caused disturbance, and guarantees that displacement spacer bar 13 plays guarantee sensor (displacement meter) and is in the state that freely stretches;

(5), confirming of observation frequency, basic statistics period and climatic effect statistics phase: through analyzing main weather effect key element amount of precipitation, the evaporation capacity basic statistics period that Feature Selection is suitable over time and climatic effect statistics phase, observation frequency should be more than 2～3 times in the basic statistics period.Short-term Changes in weather like the basin, Ningming can be known; In most cases one-time continuous rainy weather process is all below a week; Rainfall then can be eliminated at 2～3 days the significant impact of the sloping topsoil humidity short-term of side slope; Therefore, can be used as the basic statistics period of describing the main climatic change characteristics in Ningming ten days, observation frequency once was as the criterion with 3～5 days; Its annual change characteristic according to the main climatic elements in basin, Ningming (amount of precipitation, evaporation capacity and temperature) has rainy season entirely different Changing Pattern of (April～August) and dry season (September～March next year) again; Concerning the statistics that turns to observation with annual variation, can analyze by 2 different climatic effect statistics phases of rainy season and dry season, referring to Fig. 6.During concrete the statistics; The observation of the first basic statistics period in (dry season or rainy season) is a null value climatic effect can be added up the phase; Like observation to the basin, Ningming; Because observation starts from April, 2004 at the beginning of rainy season; The relative line breathing of the mean of dekan amount in rainy season (in April, 2004～2004 year August) is calculated, and can to observe initial reading be null value, and dry season (in September, 2004～2005 year January), then the average line breathing amount relatively with last observation ten days (on August 26th, 2004) in rainy season was that null value is carried out;

(6), relative line breathing of basic statistics period amount is calculated: by formula (1); Calculate the relative line breathing amount λ ti of each observation; By formula (2), calculate the mean of dekan relative line breathing amount

again

$\mathrm{\&lambda;ti}=\frac{(\mathrm{\&lambda;t}-\mathrm{\&lambda;}{i}_0)}{{\mathrm{\&lambda;}}_0}\&times;L---\left(1\right)$

In the formula: λ i ₀-displacement meter initial reading; 1 _t--the t time displacement meter reading; λ ₀--actual observation length;

L-represents observation and analysis thickness, and vertical direction is respectively 200mm, 300mm, 500mm;

${\mathrm{\&lambda;}}_{10j}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{\&lambda;ti}---\left(2\right)$

In the formula: i=1,2,3 ... N-is the observation frequency of this basic statistics period interior lines breathing amount;

(7), the vertical line breathing amount relatively of 0mm～500mm degree of depth soil layer calculates: represent the deflection of sloping top layer 0mm～200mm degree of depth soil layer vertical direction with the deflection of 0mm～parallel line of slope of 200mm degree of depth soil layer, through observing the addition of arrangement value can obtain the deflection of vertical 0mm～500mm degree of depth soil layer vertical direction the domatic top layer 0mm～200mm of the excavation slope same period and two depth layer displacement meters of 200mm～500mm;

(8), the linear attenuation supposition check of average vertical line breathing amount relatively of basic statistics period: divide dry season and rainy season to obtain the average vertical temporal evolution linear equation of line breathing amount relatively of basic statistics period of respectively observing 0cm in the shallow well～50cm degree of depth, 50cm～two observation of 100cm degree of depth soil layer by linear attenuation supposition match, with discriminant coefficient greater than 0.8 as supposing the standard of analyzing by linear attenuation.Fig. 7 has listed the Ningming expansive soil and excavated the concrete instance of differentiating of domatic swell-shrinking deformation observation linear attenuation supposition suitability: rainy season second observes the 0m～0.5m of shallow well 8 and the linear relationship of the relative line breathing of 0.5m～1.0m two depth analysis layer mean of dekan amount is y=0.51x-0.3242; Therefore its discriminant coefficient can be analyzed the data of observing shallow well 8 rainy season second by the linear attenuation supposition greater than 0.8678; More differentiation example reference table 1.

Table 1 is suitable for the observation well differentiation instance (Fig. 4 is seen in the observation well position) that the linear fit equation is analyzed

(9), set up the linear equation of the relative line breathing amount mean value of climatic effect statistics phase with change in depth: earlier by formula (3) calculate add up relative line breathing of phase amount with the climatic effect of 0.5m and the 1.0m degree of depth mean value

again by listing the mean value of relative line breathing amount that each inspection well climatic effect adds up the phase by two point form with the linear equation (4) of change in depth

$\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_d}=\frac{1}{t}\underset{j=1}{\overset{t}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_{10j}---\left(3\right)$

In the formula: j=1,2,3 ... Hop count when t-is the basic statistics in the phase of climatic effect statistics, d is two observation and analysis layer depth (m), d ₁=0.5m, d ₂=1.0m,

$\mathrm{\&lambda;}=\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}1}}}{d_2-d_1}d+{\mathrm{\&lambda;}}_{d1}-\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}1}}}{d_2-d_1}{d}_1---\left(4\right)$

In the formula: λ is the newborn vertical line breathing amount relatively of excavation expansive soil slope,

D is apart from the excavation domatic degree of depth (m)

Order $k=\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}1}}}{d_2-{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}}_1},$ $b={\mathrm{\&lambda;}}_{d1}-\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}1}}}{d_2-d_1}{\mathrm{<figure-callout\; id="1"\; label="d"\; filenames="HDA0000129446120000021.png,HDA0000129446120000031.png"\; state="\{\{state\}\}">d</figure-callout>}}_1$ Substitution (4):

λ＝kd+b (5)

(10), ask the domatic newborn swell-shrinking deformation degree of depth of expansive soil excavation: according to linear equation (5); The newborn vertical line breathing amount relatively of order excavation expansive soil slope is zero; Be λ=0, try to achieve that the corresponding degree of depth (formula (6)) is the newborn swell-shrinking deformation degree of depth of being asked when being zero with newborn swell-shrinking deformation.

$d=-\frac{b}{k}---\left(6\right)$

Concrete calculated examples is seen and has been reflected climatic effect statistics phase of setting up according to the domatic observed result of Ningming expansive soil excavation slope situation with the linear attenuation equation of the degree of depth and the domatic newborn swell-shrinking deformation degree of depth of excavation obtained in table 2. table 2.

The domatic newborn swell-shrinking deformation depth calculation instance of table 2 Ningming expansive soil excavation slope

Claims (5)

1. observation and computational methods of excavating the domatic newborn swell-shrinking deformation degree of depth of expansive soil slope is characterized in that: observation and analytical procedure are following:

(1), selects displacement meter;

(2), make displacement meter and bury installation accessories underground: bury installation accessories underground and must be able to guarantee that displacement meter does not receive the influence of soil pressure, can guarantee to observe the small deflection of the soil body of scale range again;

(3), excavation observation shallow well: respectively dig an observation shallow well at domatic each layer soil body of excavation;

(4), displacement meter is installed: select to solve the vertical observation problem of line swell-shrinking deformation amount relatively of slope table 0mm-500mm analysis layer with two displacement meters; Promptly lay first displacement meter by parallel line of slope in 0mm～200mm degree of depth; The line swell-shrinking deformation rate of supposing 0mm～200mm soil layer has isotropism; The line swell-shrinking deformation discharge observation result of parallel line of slope is converted to the observed result of vertical direction through converting; Second displacement meter then is arranged in 200mm～500mm depth layer by vertical direction; Both observed result additions have just been obtained the vertical line swell-shrinking deformation amount relatively same period of 0mm～500mm analysis layer, and the 3rd displacement meter is by be embedded in 500mm～1000mm analysis layer by vertical direction;

(5), confirming of observation frequency, basic statistics period and climatic effect statistics phase: through analyzing main weather effect key element amount of precipitation, the evaporation capacity basic statistics period that Feature Selection is suitable over time and climatic effect statistics phase, observation frequency is more than 2～3 times in the basic statistics period; During concrete the statistics, the observation of climatic effect being added up the first basic statistics period in dry season phase or rainy season is a null value;

(6), relative line breathing of basic statistics period amount is calculated: by formula (1); Calculate the relative line breathing amount λ ti of each observation; By formula (2), calculate the mean of dekan relative line breathing amount

again

$\mathrm{\&lambda;ti}=\frac{(\mathrm{\&lambda;t}-\mathrm{\&lambda;}{i}_0)}{{\mathrm{\&lambda;}}_0}\&times;L---\left(1\right)$

In the formula: λ i ₀-displacement meter initial reading; l _t--the t time displacement meter reading; λ ₀--actual observation length;

L-represents observation and analysis thickness, and vertical direction is respectively 200mm, 300mm, 500mm.

${\mathrm{\&lambda;}}_{10j}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{\&lambda;ti}---\left(2\right)$

In the formula: i=1,2,3 ... N-is the observation frequency of this basic statistics period interior lines breathing amount;

(7), the vertical line breathing amount relatively of 0mm～500mm degree of depth soil layer calculates: represent the deflection of sloping top layer 0mm～200mm degree of depth soil layer vertical direction with the deflection of 0mm～parallel line of slope of 200mm degree of depth soil layer, through observing the addition of arrangement value can obtain the deflection of vertical 0mm～500mm degree of depth soil layer vertical direction the domatic top layer 0mm～200mm of the excavation slope same period and two depth layer displacement meters of 200mm～500mm;

(8), the linear attenuation supposition check of average vertical line breathing amount relatively of basic statistics period: divide dry season and rainy season to obtain the average vertical temporal evolution linear equation of line breathing amount relatively of basic statistics period of respectively observing 0cm in the shallow well～50cm degree of depth, 50cm～two observation of 100cm degree of depth soil layer by linear attenuation supposition match, with discriminant coefficient greater than 0.8 as supposing the standard of analyzing by linear attenuation;

(9), the establishment of the climate effects of statistical average of the relative linear expansion shrinkage variation with depth of linear equations: press the formula (3) is calculated with 0.5m and 1.0m depth statistical climatic effects of shrinkage of the relative linear expansion average and then by a two-point list of the climatic effects of statistical observation wells relative linear expansion of the average shrinkage variation with depth of linear equations (4);

$\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_d}=\frac{1}{t}\underset{j=1}{\overset{t}{\mathrm{\&Sigma;}}}{\mathrm{\&lambda;}}_{10j}---\left(3\right)$

In the formula: j=1,2,3 ... Hop count when t-is the basic statistics in the phase of climatic effect statistics, d is two observation and analysis layer depth (m) .d ₁=0.5m, d ₂=1.0m.

$\mathrm{\&lambda;}=\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{d2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{d1}}}{d_2-d_1}d+{\mathrm{\&lambda;}}_{d1}-\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{d2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{d1}}}{d_2-d_1}{d}_1---\left(4\right)$

In the formula: λ is the newborn vertical line breathing amount relatively of excavation expansive soil slope, and d is apart from the excavation domatic degree of depth (m)

Order $k=\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{d2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{d1}}}{d_2-d_1},$ $b={\mathrm{\&lambda;}}_{d1}-\frac{\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{d2}}-\stackrel{\&OverBar;}{{\mathrm{\&lambda;}}_{d1}}}{d_2-d_1}{d}_1$ Substitution (4):

λ＝kd+b (5)

(10), ask the domatic newborn swell-shrinking deformation degree of depth of expansive soil excavation: according to linear equation (5); The newborn vertical line breathing amount relatively of order excavation expansive soil slope is zero; Be λ=0, try to achieve that corresponding degree of depth formula (6) is the newborn swell-shrinking deformation degree of depth of being asked when being zero with newborn swell-shrinking deformation

$d=-\frac{b}{k}---\left(6\right).$

2. the observation and the computational methods of the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope according to claim 1; It is characterized in that: the selection displacement meter described in the above-mentioned steps (1): getting 500mm is the bed thickness that change in depth is analyzed; The measurement category of displacement meter is 400mm ± 40mm, and precision is 0.01mm.

3. the observation and the computational methods of the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope according to claim 1 and 2 is characterized in that: steel device for carrying a tripot formula displacement meter is counted in the displacement described in the above-mentioned steps (1).

4. the observation and the computational methods of the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope according to claim 1 and 2; It is characterized in that: the displacement meter described in the above-mentioned steps (2) bury underground installation accessories by observation location-plate (11), installing and locating bar (12), installing and locating bar steady pin (13) and sensor spacer bar (14) totally 4 parts form; To observe location-plate (11) be contained on the installing and locating bar (12) during installation earlier; And it is fixing with installing and locating bar steady pin (13); To observe location-plate (11) squeeze in the soil of observed length scope again; Take out installing and locating bar (12) then, sensor spacer bar (14) is enclosed within middle part above the steel device for carrying a tripot formula displacement meter, and is fixed on the observation location-plate (11).

5. the observation and the computational methods of the domatic newborn swell-shrinking deformation degree of depth of excavation expansive soil slope according to claim 1 and 2 is characterized in that: the excavation observation shallow well described in the above-mentioned steps (3): respectively dig an observation shallow well that is of a size of 1m * 1m * 1m at domatic each layer soil body of excavation.

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