Stratum strength and settlement simplified calculation and analysis method, device and system

Abstract

The invention discloses a simplified calculation and analysis method, device and system for stratum strength and settlement, and the method comprises the steps: S1, taking unsaturated soil as a test object, taking natural density as a test index, and obtaining the total stress strength of the introduced natural density by constructing the relationship between the natural density and an internal friction angle and the cohesive force; s2, by taking unsaturated soil as a test object and the natural density as a test index, obtaining a stress-strain constitutive model based on the natural density; and S3, by taking the unsaturated soil as a test object and the natural density as a test index, calculating the compression deformation of the unsaturated soil introduced with the natural density according to the relationship between the natural density and the deformation modulus and based on a load test s-p curve. By the adoption of the technical scheme, foundation strength and deformation analysis is simplified.

Description

Technical Field

[0001] The present invention belongs to the field of geotechnical engineering technology, and in particular relates to a simplified calculation and analysis method, device and system for stratum strength and settlement. Background Art

[0002] In geotechnical engineering, foundation strength and deformation characteristics are important design indicators that affect the safety of building structures such as buildings, bridges, and tunnels. Existing geotechnical physical and mechanical property analysis methods rely on the natural physical properties of the stratum (water content, density, soil particle density, and degree of saturation) to analyze the critical moisture content and particle composition. Furthermore, through indoor testing, soil compression (consolidation) test indicators, bed coefficient, static lateral pressure coefficient, shear strength index, and permeability coefficient are determined. Finally, foundation strength and deformation characteristics are evaluated, and subsequent reinforcement or construction measures are implemented.

[0003] The above research process shows that traditional foundation property analysis methods are relatively complex, especially when considering issues such as slope stability, which require consideration of unsaturated soil mechanical parameters such as matrix suction. Laboratory experimental research is difficult, and the large degree of dispersion of the soil in the field hinders analytical work. Furthermore, the mechanical properties of unsaturated soil are more complex than the three-phase system of saturated soil. The presence of pores in unsaturated soil results in a force system that includes total stress and matrix suction. However, due to the complex nature of matrix suction, its measurement technology is complex both indoors and in the field. Consequently, research results on matrix suction have not been widely applied in engineering practice. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a simplified calculation and analysis method, device and system for stratum strength and settlement. By establishing a physical model, the influence of different natural densities on the stress-strain relationship, shear strength and deformation characteristics of the soil is proposed to simplify the foundation design steps and slope stability research.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A simplified calculation and analysis method for stratum strength and settlement, comprising:

[0007] Step S1: Using unsaturated soil as the test object and natural density as the test index, the total stress intensity introduced by natural density is obtained by establishing the relationship between natural density, internal friction angle, and cohesion;

[0008] Step S2: using unsaturated soil as a test object and natural density as a test index to obtain a stress-strain constitutive model based on natural density;

[0009] Step S3: Using unsaturated soil as the test object and natural density as the test index, the compression deformation of the unsaturated soil with natural density introduced is calculated based on the relationship between natural density and deformation modulus and the sp curve based on the load test.

[0010] Preferably, in step S1, the total stress intensity introduced into the natural density is:

[0011] τ f =c(ρ)+σ·tg(φ(ρ)).

[0012] Preferably, in step S2, the stress-strain constitutive model based on the natural density is:

[0013]

[0014] Preferably, in step S3, the one-dimensional compression deformation of the formation based on the natural density characteristics is:

[0015]

[0016] The present invention also provides a simplified calculation and analysis device for formation strength and settlement, comprising:

[0017] The first calculation module is used to take unsaturated soil as the test object and natural density as the test indicator. By establishing the relationship between natural density, internal friction angle, and cohesion, the total stress intensity introduced by the natural density is obtained.

[0018] The second calculation module is used to obtain a stress-strain constitutive model based on the natural density by taking the unsaturated soil as the test object and the natural density as the test index;

[0019] The third calculation module is used to calculate the compression deformation of unsaturated soil with natural density introduced by taking unsaturated soil as the test object and natural density as the test index through the relationship between natural density and deformation modulus and the sp curve based on the load test.

[0020] Preferably, the total stress intensity introduced into the natural density is:

[0021] τ f =c(ρ)+σ·tg(φ(ρ)).

[0022] Preferably, the stress-strain constitutive model based on natural density is:

[0023]

[0024] Preferably, the one-dimensional compression deformation of the formation based on the natural density characteristics is:

[0025]

[0026] The present invention also provides a simplified calculation and analysis system for formation strength and settlement, comprising: a memory and a processor, wherein the memory stores a computer program run by the processor, and the computer program executes a simplified calculation and analysis method for formation strength and settlement when run by the processor.

[0027] In order to simplify the foundation strength and deformation analysis, the present invention takes unsaturated soil as the research object and natural density as the core test indicator, and respectively constructs the relationship between natural density and internal friction angle and cohesion to simplify the foundation strength analysis; constructs the relationship between natural density and deformation modulus, and completes the simplification of foundation settlement analysis based on the load test sp curve (s is settlement and p is load). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0029] Figure 1 This is a flow chart of a simplified calculation and analysis method for formation strength and settlement according to an embodiment of the present invention;

[0030] Figure 2 is the stress-strain curve of natural density; (a) natural density is 1.97 g / cm 3 , (b) natural density is 1.92g / cm 3 , (c) natural density is 1.87 g / cm 3 , (d) natural density is 1.82g / cm 3 ;

[0031] Figure 3 is the fitting curve of cohesion;

[0032] Figure 4 is the fitting curve of the internal friction angle;

[0033] Figure 5 is the hyperbolic relationship of soil stress-strain; where (a) is the relationship between (σ1-σ2) and ε1, and (b) is the relationship between ε1 / (σ1-σ2) and ε1;

[0034] Figure 6 The stress-strain curve conversion considering the difference in natural density; (a) the natural density is 1.97 g / cm 3 , (b) natural density is 1.92g / cm 3 , (c) natural density is 1.87 g / cm 3(d) The natural density is 1.82 g / cm 3 . DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Example 1:

[0038] like Figure 1 As shown, an embodiment of the present invention provides a simplified calculation and analysis method for formation strength and settlement, including:

[0039] Step S1: Using unsaturated soil as the test object and natural density as the test index, the total stress intensity introduced by natural density is obtained by establishing the relationship between natural density, internal friction angle, and cohesion;

[0040] Step S2: using unsaturated soil as a test object and natural density as a test index to obtain a stress-strain constitutive model based on natural density;

[0041] Step S3: Using unsaturated soil as the test object and natural density as the test index, the compression deformation of the unsaturated soil with natural density introduced is calculated based on the relationship between natural density and deformation modulus and the sp curve based on the load test.

[0042] As an implementation method of the present invention, in step S1, the natural density of the parameter analysis test is based on the physical and mechanical properties of the in-situ sampling, and the sampling confining pressure is uniformly controlled at 100kPa. Based on the conventional triaxial compression test, 16 groups of unsaturated soil strength and deformation tests with different natural densities were conducted. The natural density of each group of samples (g / cm 3) were 1.97, 1.96, 1.95, 1.94, 1.93, 1.92, 1.91, 1.90, 1.89, 1.88, 1.87, 1.86, 1.85, 1.84, 1.83, and 1.82, respectively, corresponding to moisture contents of 10.32%, 11.84%, 12.53%, 14.84%, 15.58%, 16.59%, 17.09%, 17.65%, 19.65%, 19.82%, 20.21%, 23.05%, 23.82%, 24.94%, 27.13%, and 28.18%. Each group of specimens was left at a confining pressure of 100 kPa for about 12 hours to return to the initial stress state. Then, 100 kPa, 150 kPa, 200 kPa and 250 kPa were applied to the four samples in each group respectively, and sheared until they were broken. Figure 2 shown.

[0043] Based on cohesion (such as Figure 3 ) and the internal friction angle (as shown Figure 4 The relationship between the parameters c(ρ) and the natural density is constructed. And written as follows:

[0044]

[0045] φ=φ 50 +k φ ·(ρ-ρ 50 ) (2)

[0046] The total stress intensity formula that introduces the natural density can be constructed:

[0047] τ f =c(ρ)+σ·tg(φ(ρ)) (3)

[0048] There are 7 parameters c 50 、c 60 、c 80 、 k c1 、k c2 、 The parameters have clear meanings. Among them, c 50 The cohesion when the saturation is exactly equal to 50%. When the saturation is 50%, the natural density is equal to 1.94g / cm 3 , c 50 =93.31kPa;c 60 The natural density is 1.94g / cm 3 (S r =60%), c 60 =140.56kPa; c 80The cohesion when the saturation is exactly equal to 80%. When the saturation is 80%, the natural density is equal to 1.85g / cm 3 , c 80 =75.58kPa; k c1 yes Figure 3 The slope of the left straight line, k c1 =13.95;k c2 yes Figure 3 The slope of the right line, k c2 =-9.83; is the internal friction angle when the saturation is exactly equal to 50%, for Figure 4 The slope of the middle straight line, Public k c2 、 It is a negative value, reflecting that the strength of unsaturated soil decreases with the increase of natural density.

[0049] As an implementation method of the embodiment of the present invention, in step S2, the classic Duncan-Zhang hyperbolic model is as follows Figure 5 As shown in Figure 2, it is used to study the relationship between deviatoric stress and axial strain. The expression is:

[0050]

[0051] Where: a, b are test constants. For conventional triaxial compression tests, ε a =ε1.

[0052] In conventional triaxial compression tests, equation (4) can be written as:

[0053]

[0054] The effect of natural density on deviatoric stress and axial strain is as follows Figure 6 shown.

[0055] After considering the effect of natural density, the following equation is adopted:

[0056] y a =r1+s1x (6)

[0057]

[0058] Where: y a ,y b are functions of the parameters a and b in the hyperbolic model, respectively, obtained by fitting the natural density; x is the natural density, dimensionless (x = ρ / ρ0, where ρ0 = 1 g / cm 3); r1, s1, r2, s2, t2 are all undetermined fitting parameters. The test data were fitted with parameters, and the results are shown in Table 1. Substituting equations (6) and (7) into equation (5), the stress-strain constitutive model based on natural density can be obtained:

[0059]

[0060] Table 1

[0061]

[0062] As an implementation method of the embodiment of the present invention, in step S3, based on the on-site load test, such as Figure 6 The sp relationship also has hyperbolic characteristics, according to the Duncan-Zhang hyperbolic model:

[0063]

[0064] Where: E t is the deformation modulus; E0 is the initial tangent modulus; p u is the ultimate bearing capacity.

[0065] Formula (7) is the one-dimensional compression deformation formula of the formation:

[0066]

[0067] Where: v is Poisson's ratio; p is the average additional stress acting within the thickness range of the formation; H is the formation thickness.

[0068] Substituting formula (7) into formula (6) yields the one-dimensional compression deformation formula for formations based on natural density characteristics:

[0069]

[0070] Traditional foundation strength and deformation design analysis requires the measurement of numerous soil physical and mechanical parameters. This is particularly true for unsaturated soil foundations and slope stability analysis, where matric suction is difficult to measure. Therefore, the present invention establishes a simplified calculation model for formation strength and settlement based on natural density indicators. This invention has the following technical benefits:

[0071] 1. The conversion relationship between the unsaturated soil shear strength index and the natural density is proposed to simplify the strength measurement process and avoid the soil matrix suction measurement.

[0072] 2. A hyperbolic constitutive relationship of stress and strain of unsaturated soil affected by natural density is proposed.

[0073] 3. A one-dimensional compression deformation formula affected by natural density is proposed. It is particularly suitable for directly predicting foundation compression deformation from the in-situ soil natural density calculation results when it is difficult to measure the matrix suction in unsaturated strata.

[0074] Example 2:

[0075] The embodiment of the present invention further provides a simplified calculation and analysis device for formation strength and settlement, comprising:

[0076] The first calculation module is used to take unsaturated soil as the test object and natural density as the test indicator. By establishing the relationship between natural density, internal friction angle, and cohesion, the total stress intensity introduced by the natural density is obtained.

[0077] The second calculation module is used to obtain a stress-strain constitutive model based on the natural density by taking the unsaturated soil as the test object and the natural density as the test index;

[0078] The third calculation module is used to calculate the compression deformation of unsaturated soil with natural density introduced by taking unsaturated soil as the test object and natural density as the test index through the relationship between natural density and deformation modulus and the sp curve based on the load test.

[0079] As an implementation method of an embodiment of the present invention, the total stress intensity introduced into the natural density is:

[0080] τ f =c(ρ)+σ·tg(φ(ρ)).

[0081] As an implementation method of an embodiment of the present invention, the stress-strain constitutive model based on natural density is:

[0082]

[0083] As an implementation method of an embodiment of the present invention, the one-dimensional compression deformation of the formation based on the natural density characteristics is:

[0084]

[0085] Example 3:

[0086] An embodiment of the present invention also provides a simplified calculation and analysis system for formation strength and settlement, comprising: a memory and a processor, wherein the memory stores a computer program run by the processor, and the computer program executes a simplified calculation and analysis method for formation strength and settlement when run by the processor.

[0087] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A simplified calculation and analysis method for stratum strength and settlement, characterized in that: include: Step S1: Using unsaturated soil as the test object and natural density as the test index, the total stress intensity introduced by natural density is obtained by establishing the relationship between natural density, internal friction angle, and cohesion; Step S2: using unsaturated soil as a test object and natural density as a test index to obtain a stress-strain constitutive model based on natural density; Step S3: Using unsaturated soil as the test object and natural density as the test index, the compression deformation of the unsaturated soil with natural density introduced is calculated based on the relationship between natural density and deformation modulus and the sp curve based on the load test.

2. The simplified calculation and analysis method for stratum strength and settlement according to claim 1, characterized in that: In step S1, the total stress intensity introduced into the natural density is: t f = c(ρ)+σ·tg(φ(ρ)).

3. The simplified calculation and analysis method for stratum strength and settlement according to claim 2, characterized in that: In step S2, the stress-strain constitutive model based on the natural density is:

4. The simplified calculation and analysis method for stratum strength and settlement according to claim 3, characterized in that: In step S3, the one-dimensional compression deformation of the formation based on the natural density characteristics is:

5. A simplified calculation and analysis device for stratum strength and settlement, characterized in that: include: The first calculation module is used to take unsaturated soil as the test object and natural density as the test indicator. By establishing the relationship between natural density, internal friction angle, and cohesion, the total stress intensity introduced by the natural density is obtained. The second calculation module is used to obtain a stress-strain constitutive model based on the natural density by taking the unsaturated soil as the test object and the natural density as the test index; The third calculation module is used to calculate the compression deformation of unsaturated soil with natural density introduced by taking unsaturated soil as the test object and natural density as the test index through the relationship between natural density and deformation modulus and the sp curve based on the load test.

6. The simplified calculation and analysis device for stratum strength and settlement according to claim 5, characterized in that: The total stress intensity introduced into the natural density is: t f = c(ρ)+σ·tg(φ(ρ)).

7. The simplified calculation and analysis device for stratum strength and settlement according to claim 6, characterized in that: The stress-strain constitutive model based on natural density is:

8. The simplified calculation and analysis device for stratum strength and settlement according to claim 7, characterized in that: The one-dimensional compression deformation of the stratum based on the natural density characteristics is:

9. A simplified calculation and analysis system for stratum strength and settlement, characterized in that: include: A memory and a processor, wherein the memory stores a computer program executed by the processor, and when the computer program is executed by the processor, the simplified calculation and analysis method for formation strength and settlement as described in any one of claims 1 to 4 is executed.

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