CN117030977A - Clay effective stress friction angle measuring method based on flat shovel side swelling instrument DMT - Google Patents

Clay effective stress friction angle measuring method based on flat shovel side swelling instrument DMT Download PDF

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Publication number
CN117030977A
CN117030977A CN202311299035.5A CN202311299035A CN117030977A CN 117030977 A CN117030977 A CN 117030977A CN 202311299035 A CN202311299035 A CN 202311299035A CN 117030977 A CN117030977 A CN 117030977A
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test
effective stress
clay
friction angle
flat
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欧阳仲坤
刘语诺
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Shenzhen International Graduate School of Tsinghua University
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Shenzhen International Graduate School of Tsinghua University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/24—Earth materials
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D1/00—Investigation of foundation soil in situ

Abstract

The application discloses a clay effective stress friction angle measuring method based on a flat shovel side swelling instrument DMT, which comprises the following steps: carrying out a flat shovel side swelling instrument test on the clay to be tested to obtain actual measurement parameters of the clay; establishing parameter association of a hydrostatic cone penetration test and a flat shovel side dilatometer test based on a spherical cavity expansion theory, and obtaining a solving mode of the flat shovel side dilatometer test parameters equivalent to the hydrostatic cone penetration test parameters; according to the measured parameters, the effective stress friction angle of the clay is obtained by solving the test parameters of the flat shovel side swelling instrument, which are equivalent to the test parameters of the hydrostatic cone penetration test. The method of the application can generate mass data while rapidly measuring in real time on site, and solves the technical problem of rapidly evaluating the effective stress intensity of clay outdoors. Compared with the prior art, the method has the advantages that the method is firstly used for sampling back into the room and then testing, the cost is low, and the cost can be effectively saved.

Description

Clay effective stress friction angle measuring method based on flat shovel side swelling instrument DMT
Technical Field
The application relates to the field of marine geotechnical engineering geological investigation, in particular to a clay effective stress friction angle measuring method based on a flat shovel side swelling instrument DMT.
Background
The spade side dilatometer test (The Flate Dilatometer Test, DMT) and the piezocone penetration test (StaticCone Penetration, CPTU) are relatively quick in-situ tests, which can effectively, economically and conveniently infer soil formations and interpret geologic parameters. Side expansion instrument test of flat shovelThe test (DMT) basic test method is to push a flat blade into the ground and spread a 60 mm flexible steel membrane laterally with nitrogen to obtain two pressure readings at vertical depth intervals of 0.2 meters; a cone of pore pressure penetration test (CPTU) uses force and pressure sensors to obtain three readings at a depth interval of about 0.02 meters. CPTU provides parameters of depth and cone tip resistance respectively) Side friction resistance (+)>) And pore water pressure (+)>) Whereas DMT provides two readings in the field process, namely contact pressure (+)>) And expansion pressure (+)>). Both tests can evaluate various geotechnical parameters, and the interpretation program of the test of each parameter is independently formulated. The effective stress friction angle is an important index parameter for evaluating the effective stress intensity of the soil body. Effective stress friction angle (++) for interpreting soil mass>) The theory of effective stress limit plasticity was verified to be universally effective, and for CPTU, effective stress limit plastic solutions have been well documented for assessing effective stress friction angles (, from sandy soil, silty soil to clay) of various soil bodies under non-draining conditions>). DMT is advantageous in measuring soil deformation characteristics compared to CPTU, however, current interpretation procedures for DMT do not include methods to evaluate clay effective stress intensity.
Disclosure of Invention
The application aims to solve the technical problem that the effective stress intensity of clay cannot be rapidly estimated outdoors in real time in the prior art, and provides a clay effective stress friction angle measuring method based on a flat shovel side swelling instrument DMT.
In order to solve the technical problems, the application provides a clay effective stress friction angle measuring method based on a flat shovel side swelling instrument DMT, which comprises the following steps:
s1, performing a flat shovel side swelling instrument test on clay to be measured to obtain actual measurement parameters of the clay;
s2, establishing parameter association of a pore-pressure static cone penetration test and a flat shovel side dilatometer test based on a spherical cavity expansion theory, and obtaining a solving mode of flat shovel side dilatometer test parameters equivalent to the pore-pressure static cone penetration test parameters;
and S3, according to the actually measured parameters, obtaining the effective stress friction angle of the clay by a solving mode of the test parameters of the flat shovel side swelling instrument equivalent to the test parameters of the piezocone penetration test.
In some embodiments, in step S1, the measured parameters include contact pressure and inflation pressure.
In some embodiments, step S3 specifically includes:
s31, according to the actual measurement parameters, obtaining effective stress limit plastic solution by a solution mode of the flat shovel side swelling instrument test parameters equivalent to the pore-pressure static cone penetration test parameters;
s32, obtaining the effective stress friction angle based on the relation between the effective stress limit plastic solution and the effective stress friction angle.
In some embodiments, the method further comprises the steps of:
s0, obtaining the relation between the effective stress limit plastic solution and the effective stress friction angle through a pore-pressure static cone penetration test.
In some embodiments, in step S0, the effective stress limit plastic solution is a cone tip drag coefficient that satisfies the following relationship with the effective stress friction angle:
wherein,is the resistance coefficient of the cone tip->For effective stress friction angle, +.>Is the pore water pressure bearing coefficient->Is a cone tip bearing coefficient->For normalizing the pore water pressure parameter,/o>Is natural constant (18)>Is the plasticizing angle.
In some embodiments, the pore-pressure cone penetration test parameters and the spade side dilatometer test parameters each include a cone tip drag coefficient and a normalized pore water pressure parameter.
In some embodiments, the cone tip drag coefficient for the spade side dilatometer test is calculated as:
wherein,taper point resistance coefficient for flat shovel side dilatometer test,/->Net cone tip resistance for flat spade side dilatometer test,/->Stress on flat shovel side dilatometer test, < ->For the expansion pressure +.>For the contact pressure +.>Is the static pore water pressure;
the calculation formula of the normalized pore water pressure parameter of the flat shovel side dilatometer test is as follows:
wherein,normalized pore water pressure parameter for flat shovel side dilatometer test,/->The super pore water pressure generated by the penetration of the flat shovel side dilatometer test is measured.
In some embodiments, the pore water pressure generated by penetration of the hydrostatic penetration testSuper pore water pressure generated by penetration of flat shovel side dilatometer test>The following relationship is satisfied:
wherein,for the pore water pressure measured by the probe shoulder +.>Shear strength for no drainage->Is justAnd (5) a degree index.
In some embodiments, the net cone tip resistance for the spade side dilatometer test is calculated as:
。
the application also provides a medium, wherein the computer readable storage medium stores a computer program, and the computer program realizes the steps of the clay effective stress friction angle measuring method based on the flat shovel side swelling instrument DMT when being executed.
Compared with the prior art, the application has the beneficial effects that:
according to the clay effective stress friction angle measuring method based on the flat shovel side swelling instrument DMT, the measured clay is subjected to the flat shovel side swelling instrument test to obtain the actual measurement parameters of the clay, the pore-pressure static cone penetration test is established based on the sphere cavity swelling theory and is associated with the parameters of the flat shovel side swelling instrument test, the actual measurement parameters are subjected to parameter association to obtain the clay effective stress friction angle, the clay effective stress intensity is further evaluated in real time, the pressure generated in the soil stress deformation process can be measured by using the flat shovel side swelling instrument, the clay effective stress friction angle is further obtained, mass data are generated while the on-site real-time rapid measurement is achieved, and the technical problem of rapidly evaluating the clay effective stress intensity outdoors is solved. Compared with the prior art, the method has the advantages that the method is firstly used for sampling back into the room and then testing, the cost is low, and the cost can be effectively saved.
Other advantages of embodiments of the present application are further described below.
Drawings
FIG. 1 is a flow chart of a clay effective stress friction angle measurement method in an embodiment of the application;
FIG. 2 is a graph showing correlation between CPTU test and DMT test parameters according to an embodiment of the present application;
FIG. 3a is a graph showing the correlation of contact pressure parameters of CPTU test and DMT test in experimental examples of the present application;
FIG. 3b is a graph showing the relationship between the expansion pressure parameters of CPTU test and DMT test in the experimental example of the present application;
FIG. 4a is a diagram of the limiting plastic solution data derived from DMT equivalent effective theory in the experimental example of the present application;
FIG. 4b is a graph of normalized pore water pressure parameter data derived from DMT equivalent effectiveness theory in experimental examples of the present application;
FIG. 4c is a graph comparing the effective stress friction angle results (dots) obtained by the effective stress friction angle measurement method in the experimental example of the present application with the high-grade geotechnical test measurement values (dotted lines);
fig. 5 is a flow chart of a solution method for associating the CPTU test with the DMT test parameters in an embodiment of the present application.
Detailed Description
The application will be further described with reference to the following drawings in conjunction with the preferred embodiments. It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other.
It should be noted that, in this embodiment, the terms of left, right, upper, lower, top, bottom, etc. are merely relative terms, or refer to the normal use state of the product, and should not be considered as limiting.
The embodiment of the application discloses a clay effective stress friction angle measuring method based on a flat shovel side swelling instrument DMT, which is shown in figure 1 and comprises the following steps of:
s1, performing a flat shovel side swelling instrument test on clay to be measured to obtain actual measurement parameters of the clay;
s2, establishing parameter association of a pore-pressure static cone penetration test and a flat shovel side dilatometer test based on a spherical cavity expansion theory, and obtaining a solving mode of flat shovel side dilatometer test parameters equivalent to the pore-pressure static cone penetration test parameters;
and S3, obtaining the effective stress friction angle of the clay according to the actually measured parameters in a solution mode of the flat shovel side swelling instrument test parameters equivalent to the pore-pressure static cone penetration test parameters.
In step S1, the measured parameters include a contact pressure and an expansion pressure.
The step S3 specifically comprises the following steps:
s31, according to the actual measurement parameters, obtaining effective stress limit plastic solution by a solution mode of the flat shovel side swelling instrument test parameters equivalent to the pore-pressure static cone penetration test parameters;
s32, obtaining the effective stress friction angle based on the relation between the effective stress limit plastic solution and the effective stress friction angle.
In some embodiments, the method further comprises step S0 of obtaining the relation between the effective stress limit plastic solution and the effective stress friction angle through a pore-pressure static cone penetration test.
The effective stress limit plastic solution is a cone tip resistance coefficient, and the cone tip resistance coefficient and the effective stress friction angle meet the following relation:
wherein,is the resistance coefficient of the cone tip->For effective stress friction angle, +.>Is the pore water pressure bearing coefficient->Is a cone tip bearing coefficient->For normalizing the pore water pressure parameter,/o>Is natural constant (18)>Is the plasticizing angle.
The pore-pressure static cone penetration test parameters and the flat shovel side dilatometer test parameters respectively comprise cone tip resistance coefficients and normalized pore water pressure parameters.
The calculation formula of the cone tip resistance coefficient of the flat shovel side dilatometer test is:
wherein,taper point resistance coefficient for flat shovel side dilatometer test,/->Net cone tip resistance for flat spade side dilatometer test,/->Stress on flat shovel side dilatometer test, < ->For the expansion pressure +.>For the contact pressure +.>Is the static pore water pressure;
the calculation formula of normalized pore water pressure parameters of the flat shovel side dilatometer test is as follows:
wherein,normalized pore water pressure parameter for flat shovel side dilatometer test,/->The super pore water pressure generated by the penetration of the flat shovel side dilatometer test is measured.
Super pore water pressure generated by penetration of pore pressure static cone penetration testSide dilatometer test of flat spadePenetrating the generated super pore water pressure +.>The following relationship is satisfied:
wherein,for the pore water pressure measured by the probe shoulder +.>Shear strength for no drainage->Is a rigidity index.
The calculation formula of the net cone tip resistance of the flat shovel side dilatometer test is as follows:
。
the embodiment of the application also shows a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program executes the steps of the clay effective stress friction angle measuring method based on the flat shovel side swelling instrument DMT.
Examples
The solution method of the correlation of the CPTU test and the DMT test parameters is shown in FIG. 5. In CPTU penetration test, excessive pore water pressure of the silt and clay can appear>0) By using effective stress-limiting plastic solutions, i.e. cone tip drag coefficient (+)>) To evaluate the effective stress friction angle (++) at the non-drainage penetration>) The specific solving mode is as follows:
（1-1）
in the method, in the process of the application,to normalize pore water pressure parameters:
（1-2）
for net cone tip resistance->，/>For the tip drag corrected for the hole pressure,q t =q c +(1-a)u 2 ；q c a is the cone tip cross-sectional area ratio of the probe (the shape parameter of the probe) for actually measured cone tip resistance; />In order to attach the force of the force to the support,is the excess pore water pressure->For the pore water pressure measured by the probe shoulder +.>Is the static pore water pressure.
、u 2 A is measured by a vernier caliper to obtainq t ，/>For attaching stress, the dead weight of soil body is obtained from the buried depth of soil layer, and the water pressure obtained from the water depth is added to obtain +.>Thereby obtaining->、/>；
In the method, in the process of the application,is a cone tip bearing coefficient->The pore water pressure bearing coefficient is as follows:
（1-3）
（1-4）
wherein,is plasticizing angle (-40 °</><+30°) in clay, which has a value of zero, defines the size of the damage zone around the cone tip, +.>Is a natural constant; />The passive lateral stress coefficient:
（1-5）
substituting the formulas (1-2), (1-3), (1-4) into the formula (1-1), namely:
in the above-mentioned method, the step of,is a normalized value from 0 to 1, as shown in FIG. 2, the abscissa represents the cone tip drag coefficient, and the ordinate represents the effective stress friction angle, listing the corresponding +.>Is the case of the specific numerical values of>Determining the value of the above formula of +.>Is->Is a variable, thus a curve as shown in FIG. 2 is plotted, and +.>About->And->Is a relationship between the various values of (a).
For CPTU test, the shear strength of non-drainage is [ ]) The net cone tip resistance is usually evaluated (+.>) The calculation formula is as follows:
（1-6）
wherein,is an influencing factor of the net tip resistance, with an empirical value of 9 to 17. For non-drainage shearing, the sphere cavity expansion theory is based on a flat shovel side dilatometer test (DMT) principle, and the influence factor formula is as follows:
（1-7）
in the middle ofAs an index of the stiffness of the steel sheet,Gis the shear modulus. Thus, the net cone tip resistance in the CPTU test can be expressed as:
（1-8）
also, non-draining shear strength can be used in the penetration processTo express:
（1-9）
wherein the method comprises the steps ofIs an influencing factor of the excess pore water pressure. The expression provided by the sphere cavity expansion theory of the flat shovel side expansion instrument test (DMT) principle is as follows:
（1-10）
the excess pore water pressure resulting from CPTU penetration can be expressed as
（1-11）
Contact pressure measured by DMT for soft to hard whole clay [ ]) Pore water pressure measured by CPTU is equal in magnitude (/ v)>) Very similar:
（1-12）
thus, the excess pore water pressure created by CPTU penetration can be expressed as:
（1-13）
wherein,the excess pore water pressure created for DMT penetration.
The ball cavity expansion theory shows that the horizontal stress variation amplitude is:
（1-14）
the increase in radial stress can be considered to be a [ ] with DMT expansion pressure) In particular the net expansion pressure (>) Expressed as:
（1-15）
thus, the non-drainage shear strength can be expressed as:
（1-16）
the stiffness index expression for DMT is:
（1-17）
substituting formulas (1-16) and (1-17) into formulas (1-8) to obtain equivalent net cone tip resistance of DMT:
（1-18）
the above equation gives a new approach to expressing the net resistance of the CPTU test readings as the equivalent of DMT pressure.
CPTU provides the total penetration depthAnd->Reading, which is the effective stress limit plasticity method to find +.>As required. DMT reading +.>And->Can be used to obtain the necessary parameters +.>And->To be input into the effective stress limit plastic solution. Based on the above-mentioned derivation of the present application,equivalent DMT expression can be established to give cone tip drag coefficient +.>And normalized pore water pressure parameter->Equivalent of (c) a).
（1-19）
（1-20）
Acquisition from DMT dataAnd->By further passing through FIG. 2, the effective stress friction angle of the test clay was obtained (+.>）。
And->All are DMT actual measurement, are->Is static pore water pressure>In order to effectively attach stress, the water pressure can be subtracted from the attaching stress, namely, the water pressure is equal to the self weight of the soil body. Furthermore, the data measured by DMT and the parameters obtained in actual condition can be used to calculate +.>Andfurther from fig. 2, the effective stress friction angle (++>）。
Experimental example 1:
the specific experimental steps are as follows: in the same position, CPTU and DMT are penetrated, parameters obtained by carrying sensors are obtained, parameters measured by different devices are equivalent by the formula in the embodiment of the application, and the result shows that the data of 49 positions can be equivalent to each other, namely, the equivalent relationship provided in the embodiment of the application is verified based on a large amount of data, and the effect is good. Because it is based on、/>The effective stress limit plasticity theory is based on CPTU, if the parameter measured by DMT can be equivalent to CPTU, when the DMT is utilized to obtain in-situ soil parameters, and mechanical judgment is needed, the effective stress friction angle key parameter can be obtained according to the method of the embodiment of the application. Wherein the 49 locations include the point names of 49 in situ test regions, respectively Ai Masi (Amherst, massachusetts City, U.S.), ariake, japan, ballina, columbia, botgomery (Bogata), busan (Busan, korea) Korea, kelbrook Road (Colebrook Road), two racehorse fields of Brix class (Eagle Farm, australian east City), fuis (Foynes, ireland), sea defense (Hai-Phong, vietnam), haeplery (High Prairie, canada), a dense area of LillaMellosa (Lillama Melland) of Swedermand L ä n), louis Vietre (LosKelvin City, U.S. Mo Silan), langerstrongback (Monday, U.S. No. Mondin), and Momordica (Mondin)The characteristics of the materials include, but are not limited to, rfolk, county in eastern, england, northwest university (NWU, northwestern University), babusha new-inner-law (PNG, in western southwest, australia), toliter (portto Tolle, italian), salatuca (Sarapu, santalow, brazil), saro Rd 7/600 (a highway project in sweden), sco-edb (Sk å -edby, one of the city of the year, and the year, south Portland, U.S. name), strongland, bearded (the year, and the like), and the characteristics of the materials are selected from the group consisting of one of the following Charleston (N Charleston, first, west Virginia, USA), north snowing (Norkoping), onsoy (Ons Usta), propox harbor (Port of Ploce), recife (North City, northeast, brazil), saro Rd 6/900 (a highway project in Sweden), singapore (Singapore),
south glossary (uk name), saint Paul (St. Paul), sundholmen (one place in Sweden), torp (one place in Sweden), valen (one place in Sweden).
FIG. 3a is a graph showing the relationship between the contact pressure and the contact pressure parameters of CPTU test and DMT test, wherein the abscissa represents the equivalent contact pressure of CPTU in kilopascals and the ordinate represents the measured contact pressure of DMTThe touch force is expressed in kilopascals, and 1:1 Line refers to one-to-one Line. Fig. 3b is a graph showing the relationship between expansion pressure parameters of a CPTU test and a DMT test, wherein the abscissa represents the equivalent expansion pressure of the CPTU, the unit is kilopascals, the ordinate represents the expansion pressure measured by DMT, and the unit is kilopascals, and 1:1 Line means one-to-one Line. Formula in the figureIs a variation of formulas (1-18). Wherein,，/>for stress relief, add>Is static pore water pressure>To effectively exert stress, the stress can be increased by +>Minus hydrostatic pore pressure->And carrying out calculation. The variant formula shows the expansion pressure measured directly by DMTParameter and CPTU directly measured pore Water pressure +.>And (5) association of parameters. y=kx (k is a constant), which is a functional expression of this dotted line (fitted line), ++>Is an index used in statistics to measure the fitness of the regression model, indicating how much of the variance of the dependent variable is interpreted by the independent variable,/A->The closer to 1, the more interpretation of the interpreted variable by the independent variable is indicated. In the figure, the measured parameter points fall on a positive correlation line with the coefficient of about 1, namely, the parameter correlation effect of DMT and CPTU is proved to be better.
Experimental example 2:
the procedure of this experimental example is the same as that of experimental example 1, i.e. DMT is injected, measured data is measured, calculated and obtainedFurthermore, the effective stress friction angle value obtained by the method according to the embodiment of the application is compared with the value of an advanced geotechnical test (triaxial shear test and triaxial test are the same), because the geotechnical test can be regarded as a unit test, is a recognized parameter acquisition mode, and is used as a reference to be compared with the value obtained by the embodiment of the application, and the better effect is illustrated if the coincidence is better.
FIG. 4a is a graph showing the extreme plasticity solution derived from the DMT equivalent effective theory in the experimental example of the present application, wherein the abscissa represents the coefficient of cone tip resistance of DMT equivalent [ ]) The ordinate indicates the depth. FIG. 4b is a graph of normalized pore water pressure parameter derived from DMT equivalent effectiveness theory in experimental examples of the present application, wherein the abscissa represents the normalized pore water pressure parameter (+%) of DMT equivalent>) The ordinate indicates the depth. Taper point resistance coefficient (++) obtained by DMT>) And normalized pore water pressure parameter%) The calculation method of the embodiment of the application is utilized to obtain the section of the change of the effective stress friction angle of clay along with the penetration depth, which is interpreted by the DMT test, and the numerical value of the section is compared with the indoor standard consolidation non-drainage triaxial shear testAnd comparing, as shown in fig. 4c, wherein the abscissa represents the effective stress friction angle value, the ordinate represents the depth, and the display consistency is good, namely the calculation method of the embodiment of the application is reliable. Meanwhile, the penetration depth of the in-situ test is deeper, namely the soil state changes more along with the penetration depth, and the indoor unit test needs to take a plurality of groups of measurement. The above comparison highlights the advantages of the method of the embodiments of the application.
The combination of CPTU and DMT field tests can be used as a beneficial supplement for determining the rock-soil parameters of the underground environment, namely, the combination of a new DMT friction angle measuring method is used for perfecting the integrated analysis of soil body strength and deformation characteristics. The DMT tool, combined with the interpretation method (solving mode) of the embodiment of the application, can immediately obtain the effective stress intensity parameter of the effective stress friction angle in an in-situ test, and does not sample back to a laboratory for unit test. The DMT can generate mass data while rapidly measuring in real time on site, and has low cost compared with an indoor test. The method of the embodiment of the application is used for mapping the stratum of about 20 meters, and continuous data of 20 meters can be directly obtained by DMT penetration; if the sample test is performed according to the conventional laboratory, a plurality of samples are required to be taken within 20 meters and brought back to the laboratory test. The pressure reading reaction of clay in the flat shovel side swelling instrument test is systematically researched, and the effective stress intensity of the clay is calculated by analyzing and summarizing test reading data and combining the sphere cavity swelling theory.
The scheme of the embodiment of the application adopts mature flat shovel side swelling instrument equipment, has short calculation time, effectively saves cost, fills the blank of the flat shovel side swelling instrument in the aspect of calculating the effective stress intensity of clay, and is a potential soil intensity calculation method.
Compared with the prior art, the method provided by the embodiment of the application has the following innovation points:
1. the embodiment method of the application relates to the field of marine geotechnical engineering geological investigation, and aims at the situation that the physical properties and engineering mechanical properties of marine soft clay require a great deal of expertise and parameters are complex, and the effective stress friction angle of soft soil is measured based on DMT equipment data of a flat shovel side swelling instrument.
2. The method is based on the DMT field actual measurement data of the flat shovel side swelling instrument, and the effective stress friction angle of the soft soil is calculated effectively by measuring the pressure generated in the soil body stress deformation process through the DMT, so that the method can be used for further designing geotechnical structures such as foundations and evaluating the stability of slopes.
The method solves the following technical problems: the time for calculating the effective stress friction angle of soft soil by an indoor test is too long; the indoor test is expensive, the soil sample is greatly disturbed, and the real stress response of the soil body under the minimum disturbance is directly calculated on site by the method provided by the embodiment of the application, so that the method is rapid and economic.
The foregoing is a further detailed description of the application in connection with the preferred embodiments, and it is not intended that the application be limited to the specific embodiments described. It will be apparent to those skilled in the art that several equivalent substitutions and obvious modifications can be made without departing from the spirit of the application, and the same should be considered to be within the scope of the application.

Claims (10)

1. The clay effective stress friction angle measuring method based on the flat shovel side swelling instrument DMT is characterized by comprising the following steps of:
s1, performing a flat shovel side swelling instrument test on clay to be measured to obtain actual measurement parameters of the clay;
s2, establishing parameter association of a pore-pressure static cone penetration test and a flat shovel side dilatometer test based on a spherical cavity expansion theory, and obtaining a solving mode of flat shovel side dilatometer test parameters equivalent to the pore-pressure static cone penetration test parameters;
and S3, according to the actually measured parameters, obtaining the effective stress friction angle of the clay by a solving mode of the test parameters of the flat shovel side swelling instrument equivalent to the test parameters of the piezocone penetration test.
2. The clay effective stress friction angle measurement method based on flat spade side expander DMT according to claim 1, wherein in step S1, said measured parameters include contact pressure and expansion pressure.
3. The clay effective stress friction angle measurement method based on flat spade side swelling instrument DMT according to claim 1, wherein step S3 specifically comprises:
s31, according to the actual measurement parameters, obtaining effective stress limit plastic solution by a solution mode of the flat shovel side swelling instrument test parameters equivalent to the pore-pressure static cone penetration test parameters;
s32, obtaining the effective stress friction angle based on the relation between the effective stress limit plastic solution and the effective stress friction angle.
4. A clay effective stress friction angle measurement method based on a spade side expander DMT according to claim 3, further comprising the steps of:
s0, obtaining the relation between the effective stress limit plastic solution and the effective stress friction angle through a pore-pressure static cone penetration test.
5. The method for measuring the effective stress friction angle of clay based on a spade side expander DMT according to claim 3 or 4, wherein the effective stress limit plastic solution is a cone tip drag coefficient, and the cone tip drag coefficient and the effective stress friction angle satisfy the following relationship:
wherein,is the resistance coefficient of the cone tip->For effective stress friction angle, +.>Is the pore water pressure bearing coefficient->Is a cone tip bearing coefficient->For normalizing the pore water pressure parameter,/o>Is natural constant (18)>Is the plasticizing angle.
6. The method for measuring clay effective stress friction angle based on flat spade side expander DMT according to claim 1, wherein the pore-pressure static cone penetration test parameter and flat spade side expander test parameter respectively comprise cone tip resistance coefficient and normalized pore water pressure parameter.
7. The clay effective stress friction angle measuring method based on flat spade side dilatometer DMT according to claim 6, wherein the calculation formula of the cone tip resistance coefficient of the flat spade side dilatometer test is:
wherein,taper point resistance coefficient for flat shovel side dilatometer test,/->Net cone tip resistance for flat spade side dilatometer test,/->Stress on flat shovel side dilatometer test, < ->For the expansion pressure +.>For the contact pressure +.>Is the static pore water pressure;
the calculation formula of the normalized pore water pressure parameter of the flat shovel side dilatometer test is as follows:
wherein,normalized pore water pressure parameter for flat shovel side dilatometer test is +.>And the flat shovel side dilatometer tests the pressure of the excess pore water generated by penetration.
8. The clay effective stress friction angle measuring method based on flat spade side swelling instrument DMT according to claim 7, wherein the pore pressure is super pore water pressure generated by penetration of pore pressure static cone penetration testSuper pore water pressure generated by penetration of flat shovel side dilatometer test>The following relationship is satisfied: />
Wherein,for the pore water pressure measured by the probe shoulder +.>Shear strength for no drainage->Is a rigidity index.
9. The clay effective stress friction angle measurement method based on flat spade side dilatometer DMT of claim 7, wherein the calculation formula of the net cone tip resistance of the flat spade side dilatometer test is:
。
10. a computer readable storage medium storing a computer program, characterized in that the computer program when executed implements the steps of the clay effective stress angle measurement method based on a spade side expander DMT according to any one of claims 1 to 9.
CN202311299035.5A 2023-10-09 2023-10-09 Clay effective stress friction angle measuring method based on flat shovel side swelling instrument DMT Withdrawn CN117030977A (en)

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US20200109533A1 (en) * 2018-10-09 2020-04-09 North Carolina State University Portable mini dynamic penetration and torque (mdpt) device
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CN106759220A (en) * 2017-02-20 2017-05-31 中铁第四勘察设计院集团有限公司 The method that coefficient of static earth pressure is quickly determined using static cone penetration resistance
US20200109533A1 (en) * 2018-10-09 2020-04-09 North Carolina State University Portable mini dynamic penetration and torque (mdpt) device
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