CN103061320A - Method for determining soil permeability coefficient on basis of piezocone sounding - Google Patents

Abstract

The invention provides a method for determining a soil permeability coefficient on the basis of piezocone sounding. The method includes steps of firstly, determining the depth of a piezocone sounding hole, the radius of a conical head and the underground water level of a field according to a piezocone sounding report and determining division of soil layers by a Robertson soil layer classification map; secondly, acquiring soil samples from the different soil layers, testing densities of the soil samples and determining unit weights of the soil layers; thirdly, determining piezocone sounding standard parameters which include pore water pressure ratios and standard tip resistance according to parameters obtained in the first step and the second step; fourthly, determining a permeability coefficient index according to the piezocone sounding standard parameters acquired in the third step; fifthly, determining coefficients of the soil layers in initial radial distribution of excessive pore pressure according to the division of the soil layers; and sixthly, determining the soil permeability coefficient according to results obtained from the first step, the second step, the third step, the fourth step and the fifth step. The method has the advantages that the soil permeability coefficient can be accurately determined, and the method brings great convenience for survey and design for soil permeability.

Description

Press static sounding to determine the method for soil body osmotic coefficient based on the hole

Technical field

What the present invention relates to is a kind of method of construction engineering technical field, specifically a kind of method of determining soil body osmotic coefficient based on hole pressure static sounding.

Background technology

The transmission coefficient of the soil body is an important parameter of the geotechnical engineerings such as the stability analysis design of foundation pit dewatering design, foundation settlement estimation, side slope, and the transmission coefficient of the Obtaining Accurate soil body has important practical meaning in engineering.The method of determining soil body osmotic coefficient in the engineering mainly contains laboratory test and field trial.There is more shortcoming in laboratory test: 1) the soil sample disturbance is larger; 2) simulated field conditions exactly; 3) workload is large, test period is long, expense is high.The transmission coefficient that laboratory test is measured and the actual value of the on-the-spot soil body have larger difference, and especially when more thin sand or weak intercalated layer were arranged in the ground, error was larger.Present field trial testing complex, work plane and workload are larger, and the time is long, and cost compare is high.

Along with the development of in-situ testing technique, the hole presses the static sounding technology as a kind of novel in-situ testing technique, is widely applied in engineering investigation, as dividing soil layer, differentiate great soil group, determining soil parameters etc.Static sounding is pressed in the hole, it is the pore water pressure static sounding, it is the sensing element that permeable device and measurement pore water pressure have been installed at the probe of standard static sounding, static point resistance, side friction power and pore water pressure by continuous measurement conehead place carry out in-situ test, have that expense is low, good reliability, exploration cycle is short, equipment is light, simple operation and other advantages.Press static sounding to determine that the soil body osmotic coefficient method is mainly empirical method and the test of dissipating with the hole at present.The former region is stronger, and uncertain factor is higher, and deviation is larger; The latter need to test for different soil layers, and workload is large, length consuming time, and cost is high.Therefore, in the urgent need to a kind of method that need not dissipate test and press static sounding directly just can accurately test soil body osmotic coefficient with the hole, thereby bring huge facility to engineering investigation.

Through existing technical literature retrieval is found, Elsworth in 2005 etc. are at " Journal of Geotechnical and Geoenvironmental Engineering " (2005, Vol.131, " Permeability determination from on-the-fly piezocone sounding(presses static sounding to determine fast permeability based on the hole) " of delivering No.5pp.643-653) provided one and half theoretical semiempirical definite methods, but the method only is only applicable to preferably sand of the soil of partial drainage condition and water permeability.Research based on Elsworth, Chai equals 2011 at " G é otechnique " (2011, Vol.61, " Estimating hydraulic conductivity from piezocone sounding(presses the static sounding calculation permeability coefficient based on the hole) " of delivering No.00pp.1-10) also provided the method for a definite transmission coefficient, initially to press distribution function be that specific stickiness stratum is suitable in super hole but the method relies on empirical assumption, the test result of gained and the stratum of China are widely different, are difficult to direct application.

Summary of the invention

For defective of the prior art, the definite method that the purpose of this invention is to provide a kind of soil body osmotic coefficient, press the static sounding report to determine on-the-spot soil layer division and relevant parameter by the hole, obtain simultaneously the severe of on-the-spot soil according to density test, thereby determine canonical parameter and the transmission coefficient index of hole pressure static sounding, divide definite clay distribution coefficient according to soil layer, finally determine the transmission coefficient of the soil body, thereby design brings convenience to geotechnical investigation.

The present invention is achieved by the following technical solutions, may further comprise the steps:

The first step, press the static sounding report to determine that the hole presses depth H, the conehead radius a and relative groundwater table H in static sounding hole by the hole _w, and determine that with Robertson soil layer classification chart soil layer divides.

Described hole presses static sounding to refer to: be that 60 °, floor space are 1000mm with the conehead angle ², sidewall friction cylinder surface area is 15000mm ²The hole of standard press the static sounding penetrometer to be pressed in the soil body with the penetrating speed of 0.02m/s, thereby test static point resistance q _c, side friction power f _sWith pore water pressure u _a

Described hole presses the degree of depth in static sounding hole to refer to: the distance at the bottom of from pressure static sounding aperture, hole to the hole.

Described relative groundwater table refers to: press the static sounding aperture to the distance of groundwater table from the hole, when groundwater table was positioned under the pressure static sounding aperture, hole, groundwater table was negative value relatively; Groundwater table is positioned at the hole when pressing on the static sounding aperture, relatively groundwater table be on the occasion of.

Described Robertson soil layer classification chart refers to: with frictional ratio R _f(%) be abscissa, static point resistance q _cBe the vertical soil layer classification chart that plots of sitting, according to test data, this figure can be divided into foundation soil different soil layers.

Described frictional ratio R _fRefer to: side friction power f _sWith static point resistance q _cRatio, get percentage.

Described soil layer is divided and referred to: foundation soil is stratification, and different soil layers has different character.By the soil layer sum n in the depth bounds in pressure static sounding hole, the definite hole of soil layer division and the degree of depth of each soil layer.

Second step, obtain soil sample from different soil layers, carry out density test, determine soil layer severe.

The described soil sample of obtaining refers to: use thin-wall sampler, fetch earth in the MTD scope at the scene, be used for doing indoor density test, the amount of fetching earth is determined according to the test specimen amount, is no less than three test specimens with every layer of soil and is advisable.

Described density test refers to: record the wet density of each soil layer by core cutter method isodensity test method, and calculate corresponding severe.

The severe of described soil satisfies formula:

γ＝ρg

Wherein, γ is the severe of soil, and ρ is wet density, and g is acceleration of gravity, the approximate 10m/s that gets ²

The 3rd step, the hole that obtains according to the first step press the degree of depth, conehead radius and the relative groundwater table in static sounding hole and soil layer severe parameter that second step obtains to determine that the hole presses the canonical parameter of static sounding, and namely pore water pressure compares and the standard static point resistance.

Described pore water pressure ratio satisfies formula:

$B_q=\frac{u_a-u_s}{q_c+u_a(1-\mathrm{\β})-{\mathrm{\σ}}_{v0}}$

Wherein, B _qThe pore water pressure ratio, u _aPore water pressure, u _sInitial static pore water pressure, q _cBe static point resistance, β is the correction area ratio, gets 0.84, σ _V0It is initial vertical total stress.

Described initial static pore water pressure satisfies formula:

u _s=γ _wh

Wherein, γ _wThe severe of water, the approximate 10kN/m that gets ³H is the degree of depth of the following soil body of groundwater table.

The degree of depth of the following soil body of described groundwater table satisfies formula:

h=H+H _w

Wherein, H is the degree of depth that the static sounding hole is pressed in the hole, is obtained H by the first step _wBe relative groundwater table, obtained by the first step.

Described initial vertical total stress satisfies formula:

${\mathrm{\σ}}_{v0}=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\γ}}_i{h}_i$

Wherein, n is the interior soil layer sum of depth bounds that the static sounding hole is pressed in the hole, is obtained γ by the first step _iBe the severe of i layer soil, obtained by second step, h _iBe the degree of depth of i layer soil, obtained by the first step.

Described standard static point resistance satisfies formula:

$Q_t=\frac{q_c+u_a(1-\mathrm{\β})-{\mathrm{\σ}}_{v0}}{{\mathrm{\σ}}_{v0}^{\′}}$

Wherein, Q _tThe standard static point resistance, σ ' _V0It is initial vertical effective stress.

Described initial vertical effective stress refers to: the vertical intergranular stress that soil particle transmits in the soil body, satisfy formula:

${\mathrm{\σ}}_{v0}^{\′}={\mathrm{\σ}}_{v0}-u_s=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\γ}}_i{h}_i-{\mathrm{\γ}}_{w}h$

The 4th step, press the canonical parameter of static sounding to determine the transmission coefficient index according to the 3rd hole that obtain of step.

Described transmission coefficient index satisfies formula:

Work as B _qQ _t＜0.45 o'clock, $K_D=\frac{1}{B_q{Q}_t};$

Work as B _qQ _t〉=0.45 o'clock, $K_D=\frac{0.044}{{\left(B_q{Q}_t\right)}^{4.91}}$

Wherein, K _DThe transmission coefficient index, dimensionless, B _qThe pore water pressure ratio, Q _tThe standard static point resistance, B _qAnd Q _tBy the 3rd the step obtain.

The 5th goes on foot, divides according to soil layer the soil layer factor alpha of determining in the pressure radial distribution of initial super hole.

Described initial super hole presses radial distribution to refer to: during the conehead injection soil body, near the radial distribution of the pore water pressure conehead before excess pore water pressure not yet dissipates, satisfy formula:

$u-u_s=(u_a-u_s)e^{-\mathrm{\α}(\frac{r}{a}-1)}$

Wherein, u is the pore water pressure that any point on the distribution curve is pressed in this super hole, u _sInitial static pore water pressure, u _aBe pore water pressure, r is that any point is apart from the distance of conehead on this super hole pressure distribution curve, and a is the conehead radius.

Described α refers to the soil layer coefficient, divides according to soil layer and determines, be specifically as follows: clay gets 0.5; Silty clay gets 0.3; Silt gets 0.1; Sandy silt gets 0.05; Sand gets 0.01.

The 6th step, according to the above-mentioned first step to the result in five steps, determine the transmission coefficient of soil.

The transmission coefficient of described soil refers to: the factor of proportionality of the water permeability of reflection soil, satisfy formula:

$k=\frac{a{\mathrm{\&gamma;}}_w\mathrm{<figure-callout\; id="2"\; label="U\; K\; D"\; filenames="HDA00002711003900011.png,HDA00002711003900012.png"\; state="\{\{state\}\}">U</figure-callout>}{K}_D{}_{}}{2\mathrm{\&alpha;}{\mathrm{\&sigma;}}_{v0}^{\&prime;}}$

Wherein, k is the transmission coefficient of soil, and U is penetrating speed, and U is obtained by the first step.

Compared with prior art, the present invention has following beneficial effect:

The present invention relies on dislocatioln theory, continuity theory and Darcy's law, when having considered hole pressure static sounding, the impact that initial excess pore water pressure characteristic distributions is calculated conehead surface hydraulic gradient, avoid forefathers to rely on pure experience to determine initial excess pore water pressure characteristic distributions, cause the unreliability that soil body osmotic coefficient is determined.The present invention mainly is that method is simple to traditional method advantage in actual applications, and consuming time shorter, expense is low, and is less to soil disturbance, and can access layer depth continually varying transmission coefficient everywhere.Especially when more thin sand or weak intercalated layer were arranged in the ground, conventional method was because on-the-spot restriction of fetching earth causes the difficulty of indoor soil sample making, and the present invention can test the transmission coefficient of thin layer or weak intercalated layer continuously.The present invention is applicable to the hole and presses static sounding to determine the problem of soil body osmotic coefficient.

Description of drawings

By reading the detailed description of non-limiting example being done with reference to the following drawings, it is more obvious that other features, objects and advantages of the present invention will become:

Fig. 1 is embodiment soil layer classification chart.

Fig. 2 is that the embodiment hole presses the soil layer in the static sounding report to divide and test result.

Fig. 3 is the definite soil body osmotic coefficient of embodiment this method and the comparison diagram of test value and normal value.

The specific embodiment

The present invention is described in detail below in conjunction with specific embodiment.Following examples will help those skilled in the art further to understand the present invention, but not limit in any form the present invention.Should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, can also make some distortion and improvement.These all belong to protection scope of the present invention.

Embodiment:

The present embodiment presses the static sounding test result that definite method of hole pressure static sounding test soil body osmotic coefficient is described with the hole, does not have the operation of special instruction in the present embodiment, carries out with reference to the method that has provided in the summary of the invention, is not giving unnecessary details at this.

The present embodiment is specific as follows described:

Certain hole presses the static sounding test site to be positioned at Shanghai, presses the static sounding test report according to the hole, and this hole presses the static sounding hole to be positioned at the bottom of Huangpu River, groundwater table is than the high 5.85m in aperture, hole depth is 35.7m, and it is 0.02185m that the used conehead radius of static penetrometer is pressed in the hole, and penetrating speed is 0.02m/s.

The first step, press the static sounding report to determine relevant parameter by the hole, and determine the soil layer division with Robertson soil layer classification chart.

At first, press the static sounding report according to the hole, the degree of depth that obtains this pressure static sounding hole, hole is 35.7m, and the conehead radius is 0.02185m, and penetrating speed is 0.02m/s, groundwater table is 5.85m relatively.

Secondly, press the static sounding report according to the hole, can obtain static point resistance q _cWith frictional ratio R _f(%) with the curve of change in depth, see Fig. 2, with the frictional ratio R of any depth _f(%) be abscissa, static point resistance q _cFor the point-rendering of ordinate in Robertson soil layer classification chart, see Fig. 1, zone according to point residing different soil in Robertson soil layer classification chart then can be divided into five layers from top to bottom by the degree of depth with the on-the-spot soil body: the 1st layer (0.0～5.51m) is the silt clay layer; The 2nd layer (5.51～15.03m) is the Muddy Bottoms farinose argillic horizon; The 3rd layer (15.03～29.54m) is the grey farinose argillic horizon; The 4th layer (29.54～32.32m) is the dark green silty clay layer; The 5th layer (32.32～35.71m) sandy silt layers are seen Fig. 2.

Second step, obtain soil sample from different soil layers, carry out density test, determine soil layer severe.

Use thin-wall sampler, fetch earth in each soil depth scope at the scene, got by core cutter method density test method, the density of the 1st layer of soil is 1.73g/cm ³, then this layer severe is

γ=ρg=1.73×10=17.3kN/m ³

The rest may be inferred, and the density of the 2nd layer of soil is 1.78g/cm ³, severe is 17.8kN/m ³The density of the 3rd layer of soil is 1.78g/cm ³, severe is 17.8kN/m ³The density of the 4th layer of soil is 2.02g/cm ³, severe is 20.2kN/m ³The density of the 5th layer of soil is 1.96g/cm ³, severe is 19.6kN/m ³

The 3rd goes on foot, determines the canonical parameter of hole pressure static sounding.

Take the 10m depth as example, the computational process of arbitrary depth is described:

Got by the first step, second step that two soil layer: 0.0～5.51m are arranged in the 10m depth bounds is the silt clay layer, severe is 17.3KN/m ³5.51～10m is the Muddy Bottoms farinose argillic horizon, severe is 17.8kN/m ³, the pore water pressure u at 10m place _aBe 0.37831MPa, static point resistance q _cBe 0.60177MPa, the following soil body degree of depth of groundwater table h is 15.85m, then the 10m depth

Initial static pore water pressure u _sFor

u _s=γ _wh=10×15.85=0.1585MPa

Initial vertical total stress σ _V0For

${\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="HDA00002711003900011.png,HDA00002711003900012.png"\; state="\{\{state\}\}">v</figure-callout>}0}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&gamma;}}_i{h}_i=10\&times;5.85+17.3\&times;5.51+17.8\&times;(10-5.51)=0.23375\mathrm{MPa}$

Initial vertical effective stress σ ' _V0For

${\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="HDA00002711003900011.png,HDA00002711003900012.png"\; state="\{\{state\}\}">v</figure-callout>}0}^{\&prime;}={\mathrm{\&sigma;}}_{v0}-u_s=0.23375-0.1585=0.07525\mathrm{MPa}$

Pore water pressure compares B _qFor

$B_q=\frac{u_a-u_s}{q_c+u_a(1-\mathrm{\&beta;})-{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="HDA00002711003900011.png,HDA00002711003900012.png"\; state="\{\{state\}\}">v</figure-callout>}0}}=\frac{0.37831-0.1585}{0.60177+0.37831\&times;(1-0.84)-0.23375}=0.512916$

Standard static point resistance Q _tFor

$Q_t=\frac{q_c+u_a(1-\mathrm{\&beta;})-{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="HDA00002711003900011.png,HDA00002711003900012.png"\; state="\{\{state\}\}">v</figure-callout>}0}}{{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="HDA00002711003900011.png,HDA00002711003900012.png"\; state="\{\{state\}\}">v</figure-callout>}0}^{\&prime;}}=\frac{0.60177+0.37831\&times;(1-0.84)-0.23375}{0.07525}=5.695011$

The 4th goes on foot, determines the transmission coefficient index.

Go on foot by the 3rd

B _qQ _t=0.512916×5.695011=2.921062>0.45

Transmission coefficient index K then _DFor

$K_D=\frac{0.044}{{\left(B_q{Q}_t\right)}^{4.91}}=\frac{0.044}{{\left(2.921062\right)}^{4.91}}=2.28\&times;{10}^{-4}$

The 5th goes on foot, divides according to soil layer the soil layer factor alpha of determining in the pressure radial distribution of initial super hole.

Take the 10m depth as example, the computational process of arbitrary depth is described:

Getting the 10m place by the first step is the Muddy Bottoms silty clay, and then initial super hole, 10m place presses the soil layer factor alpha in the radial distribution to get 0.3.

The transmission coefficient of the 6th step, definite soil.

Take the 10m depth as example, the transmission coefficient deterministic process of arbitrary depth is described:

Getting the conehead radius by the first step is 0.02185m, and penetrating speed is 0.02m/s, and then the transmission coefficient of the soil body 10m depth soil body is

$k=\frac{a{\mathrm{\&gamma;}}_{\mathrm{<figure-callout\; id="2"\; label="w\; UK\; D"\; filenames="HDA00002711003900011.png,HDA00002711003900012.png"\; state="\{\{state\}\}">w</figure-callout>}}{\mathrm{UK}}_D{}_{}}{2\mathrm{\&alpha;}{\mathrm{\&sigma;}}_{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="HDA00002711003900011.png,HDA00002711003900012.png"\; state="\{\{state\}\}">v</figure-callout>}0}^{\&prime;}}=\frac{0.02185\&times;10\&times;0.02\&times;2.28\&times;{10}^{-4}}{2\&times;0.3\&times;0.07525}=2.2068\&times;{10}^{-8}m/s$

As shown in Figure 3, the soil body osmotic coefficient that the embodiment of the invention is determined and the comparison diagram of test value and normal value can be found out, the present embodiment can be determined the transmission coefficient of the soil body more accurately, compare former method, more accurate, brought very large convenience for the prospective design of soil body penetration.

Above specific embodiments of the invention are described.It will be appreciated that, the present invention is not limited to above-mentioned specific implementations, and those skilled in the art can make various distortion or modification within the scope of the claims, and this does not affect flesh and blood of the present invention.

Claims (8)

1. press static sounding to determine the method for soil body osmotic coefficient based on the hole for one kind, it is characterized in that may further comprise the steps:

The first step, press the static sounding report to determine that the hole presses depth H, the conehead radius a and relative groundwater table H in static sounding hole by the hole _w, and determine that with Robertson soil layer classification chart soil layer divides;

Second step, obtain soil sample from different soil layers, carry out density test, determine soil layer severe;

The 3rd step, the hole that obtains according to the first step press the degree of depth, conehead radius and the relative groundwater table in static sounding hole and soil layer severe parameter that second step obtains to determine the canonical parameter of hole pressure static sounding, and namely pore water pressure compares B _qWith standard static point resistance Q _t

The 4th step, press the canonical parameter of static sounding to determine the transmission coefficient index according to the 3rd hole that obtain of step;

Described transmission coefficient index satisfies formula:

Work as B _qQ _t＜0.45 o'clock,

Work as B _qQ _t〉=0.45 o'clock,

Wherein, K _DThe transmission coefficient index, dimensionless, B _qThe pore water pressure ratio, Q _tThe standard static point resistance, B _qAnd Q _tBy the 3rd the step obtain;

The 5th goes on foot, divides according to soil layer the soil layer factor alpha of determining in the pressure radial distribution of initial super hole;

Described initial super hole presses radial distribution to refer to: during the conehead injection soil body, near the radial distribution of the pore water pressure conehead before excess pore water pressure not yet dissipates, satisfy formula:

Wherein, u is the pore water pressure that any point on the distribution curve is pressed in this super hole, u _sInitial static pore water pressure, u _aBe pore water pressure, r is that any point is apart from the distance of conehead on this super hole pressure distribution curve, and a is the conehead radius; Described α refers to the soil layer coefficient, divides according to soil layer and determines:

The 6th step, according to the above-mentioned first step to the result in five steps, determine the transmission coefficient of soil;

The transmission coefficient of described soil refers to: the factor of proportionality of the water permeability of reflection soil, satisfy formula:

Wherein, k is the transmission coefficient of soil, and a is the conehead radius, γ _wBe the severe of water, U is that first step hole presses the static sounding mesopore to press the penetrating speed of static sounding penetrometer, K _DBe the transmission coefficient index, α is the soil layer coefficient, σ ' _V0It is initial vertical effective stress.

2. according to claim 1ly press static sounding to determine the method for soil body osmotic coefficient based on the hole, it is characterized in that, in the first step, described hole presses static sounding to refer to: be that 60 °, floor space are 1000mm with the conehead angle ², sidewall friction cylinder surface area is 15000mm ²The hole of standard press the static sounding penetrometer to be pressed in the soil body with the penetrating speed of 0.02m/s, thereby test static point resistance q _c, side friction power f _sWith pore water pressure u _a

3. the method for determining soil body osmotic coefficient based on hole pressure static sounding according to claim 1 is characterized in that, in the first step, described Robertson soil layer classification chart refers to: with frictional ratio R _f(%) be abscissa, static point resistance q _cBe the vertical soil layer classification chart that plots of sitting, according to test data, this figure is divided into different soil layers with foundation soil.

4. according to claim 1ly press static sounding to determine the method for soil body osmotic coefficient based on the hole, it is characterized in that, in the second step, the described soil sample of obtaining refers to: use thin-wall sampler, fetch earth in the MTD scope at the scene, be used for doing indoor density test, the amount of fetching earth is definite according to the test specimen amount, and every layer of soil is no less than three test specimens.

5. each described method of determining soil body osmotic coefficient based on hole pressure static sounding is characterized in that according to claim 1-4, and in the 3rd step, described pore water pressure ratio satisfies formula:

Wherein, B _qThe pore water pressure ratio, u _aPore water pressure, u _sInitial static pore water pressure, q _cBe static point resistance, β is the correction area ratio, gets 0.84, σ _V0It is initial vertical total stress;

Described initial static pore water pressure satisfies formula:

u _s=γ _wh

Wherein, γ _wBe the severe of water, h is the degree of depth of the following soil body of groundwater table;

Described initial vertical total stress satisfies formula:

Wherein, n is the soil layer sum in the depth of penetration scope, is obtained by the first step; γ _iBe the severe of i layer soil, obtained by second step; h _iBe the degree of depth of i layer soil, obtained by the first step.

6. the method for determining soil body osmotic coefficient based on hole pressure static sounding according to claim 5 is characterized in that, described standard static point resistance satisfies formula:

Wherein, Q _tThe standard static point resistance, σ ' _V0It is initial vertical effective stress.

7. the method for determining soil body osmotic coefficient based on hole pressure static sounding according to claim 6 is characterized in that, described initial vertical effective stress refers to: the vertical intergranular stress that soil particle transmits in the soil body, satisfy formula:

8. each described method of determining soil body osmotic coefficient based on hole pressure static sounding is characterized in that, in the 5th step according to claim 1-4, described α refers to the soil layer coefficient, is specially: clay gets 0.5, and silty clay gets 0.3, silt gets 0.1, and sandy silt gets 0.05, and sand gets 0.01.

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