Description:DESCRIPTION:
Field of the invention:
[0001] The present disclosure pertains to the technical field of correlating shear strength parameters for coarse and fine-grained soils, in specific, relates to a method for correlating the shear strength parameters, including the angle of shearing resistance (F) and cohesion (C) values, of inorganic silt with low compressibility (ML soils) using corrected Standard Penetration Test (SPT) (N1)60 data.
Background of the invention:
[0002] Standard penetration test (SPT) is an in-situ dynamic penetration test designed to determine the density and compressibility of granular soils. It is also commonly used to determine the consistency of stiff or stony, cohesive soils. The standard penetration test is conducted by means of the standard split spoon, and providing data about the resistance of the soils to penetration, which can be used to evaluate standard strength data, such as N values (number of blows per 30 cm of penetration using the standard split spoon) of the soil. The advantages of test is being carried out in routine exploration boreholes of varied diameters and its ability to give other geotechnical properties that may be related to crude but straight forward empirical design rules.

[0003] The strength characteristics of natural soils are strongly influenced by the geologic processes of soil formation. Hence, it is possible to identify strength characteristics that are common to soils within broadly defined groups. Groups with well-defined characteristics include saturated cohesion less soils, softly saturated cohesive soils, severely over consolidated clays, etc.

[0004] For example, the value of Phi (F) of the saturated cohesion less soils ranges from about 27 to 45° or more and depends on several factors. For a given soil, the value of F increases as the relative density increases. Particle size distribution and particle size affect the value of F in soils with similar relative density. The value of F for a well graded soil may be several degrees greater than that for a uniform soil of the same average particle size and shape. The same is true when a soil composed of angular grains is compared with one made up of rounded grains. The effect of moisture on phi is small and amounts to no more than 1 or 2 degrees for coarse grained soils.

[0005] Every civil engineer builds stable structures such as buildings, bridges, highways, tunnels, dams, and towers. Therefore, the proper foundation soil is necessary to build the structure. In order to successfully access the suitability of that soil to construct a safe foundation and as construction materials, information about its properties is typically necessary. Therefore, understanding soils detailed geotechnical, physical, and engineering properties is very essential.

[0006] Bridges and railways constructed are planned for a 100-year span. So, the structures constructed should be designed with this in mind. Nowadays, climate change has brought many challenges, especially for hydro and geotechnical soil formations, as well as abrupt changes in soil strata caused by flash floods, drought, sudden lowering of the water table, etc. Hence, the geotechnical design should be done considering these points, and hence the basic shear parameters ‘C’ and Phi (F) should be very carefully chosen in case, they are not obtained from laboratory tests.

[0007] In existing technology, a correlation method for determining the shear strength parameters of coarse and fine grained soils is known. A comparative analysis of angle of shearing resistance of soil obtained from existing correlation using relative density and Phi value (F) obtained from laboratory tests and angle cohesion value “C” of fine grained soil obtained from correlation using plasticity index and SPT (N1)60 value and C (cohesion) value obtained from laboratory tests. In the design of reinforced concrete (RC) bridges, the error in considering the shear parameters of the soil may lead to insufficient reliability levels. Therefore, it is necessary to estimate more reliable values of shear parameters and the variability of soil properties, which can significantly affect the bridge behavior. However, this comparative method investigates the error in the prediction of the angle of shearing resistance (F) based on the relative density and ‘C’ value of for ML soils. Moreover, the method might not provide reliable information on the shear strength of soil.

[0008] Therefore, there is a need for a reliable method for correlating shear strength parameters of inorganic silt include angle of shearing resistance (F) and cohesion (C) values of ML soils based on Standard Penetration Test (SPT) (N1)60 data. There is also a need for a method that treats the inorganic silt with a clay percentage for precise determination of the shear strength, and cohesion. There is also a need for a method that provides more reliable estimates of the soil actual shear strength, making it safer and more cost-effective. Further, there is also a need for a method that estimated errors for both parameters are expected to be within a range, offering a significant improvement over existing methods that often lead to overestimations.
Objectives of the invention:
[0009] The primary objective of the present invention is to provide a method for correlating shear strength parameters of inorganic silt with low compressibility (ML) include angle of shearing resistance (F) and cohesion (C) values of ML soils based on corrected Standard Penetration Test SPT (N1)60 data.

[0010] The other objective of the present invention is to provide a method that provides more reliable estimates of the soil actual shear strength, making it safer and more cost-effective.

[0011] The other objective of the present invention is to provide a method that enhances the accuracy of shear strength estimations by considering the clay content within the inorganic silt, leading to more reliable predictions.

[0012] The other objective of the present invention is to provide a method that correlates Phi (F) and C values based on SPT (N1)60 values and the clay percentage within the ML soil, comparing laboratory test results with existing correlations.

[0013] Yet another objective of the present invention is to provide a method that provide a more reliable method for assessing the shear strength of inorganic silt in the allocated region, contributing to a safer and more economical foundation for infrastructure projects.

[0014] Further objective of the present invention is to provide a method that estimated errors for both parameters are expected to be within a range of 10%, offering a significant improvement over existing methods that often lead to overestimations.
Summary of the invention:
[0015] The present disclosure proposes a method for correlating shear strength parameters of inorganic silt with low compressibility. The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

[0016] In order to overcome the above deficiencies of the prior art, the present disclosure is to solve the technical problem to provide a method for correlating shear strength parameters of inorganic silt include angle of shearing resistance (F) and cohesion (C) values of ML soils based on Standard Penetration Test (SPT) (N1)60 data.

[0017] According to one aspect, the invention provides a method for correlating shear strength parameters of inorganic silt with low compressibility (ML) soil. At one step, the corrected standard penetration test (SPT) data (N) attains on an allocated region for soil sample. At another step, the representative soil samples are collects from the allocated region corresponding to the SPT data. At another step, laboratory tests are performs on the collected soil samples to determine shear parameters (F) and cohesion (C), and plasticity characteristics and calculate SPT (N1)60.

[0018] At another step, the F and C values obtained from the laboratory tests and compared with the values estimated using existing correlations based on the SPT (N1)60 data. At another step, developed a new correlation equation based on the identified relationship to estimate the Phi value (F) of an ML soil sample based on its SPT (N1)60 data. Further, at another step, the newly developed correlations are validates with correlation equations using data from additional boreholes within the allocated region.

[0019] In one embodiment, the step of developing guidelines for determining the cohesion (C) value of the ML soil sample based on the clay content. In one embodiment, the guidelines for determining the C value include a relation between clay content and a pre-defined range of ‘C’ values.

[0020] In one embodiment, the existing correlations used for comparison include Stroud's correlation for cohesion (C) and Meyerhof's correlation for the angle of shearing resistance (F). In one embodiment, the new correlation equations are configured to estimate the F and C values with an error margin of around 10 percent compared to the laboratory determined values.

[0021] In one embodiment, the method is assessing the soil resistance properties of correction of overburden pressure at a deeper depth and correction of saturated fine sand and silts. In one embodiment, the laboratory test conducted on the collected soil samples to determine natural moisture content, dry unit weight, specific gravity, and grain size analysis.

[0022] Further, objects and advantages of the present invention will be apparent from a study of the following portion of the specification, the claims, and the attached drawings.
Detailed description of drawings:
[0023] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, explain the principles of the invention.

[0024] FIG. 1 illustrates a flowchart of a method for correlating shear strength parameters of inorganic silt, in accordance to an exemplary embodiment of the invention.

[0025] FIG. 2 illustrates a block diagram of the correlating shear strength parameters of inorganic silt, in accordance to an exemplary embodiment of the invention.

[0026] FIG. 3 illustrates a graphical representation of shear strength, plasticity index and SPT N value from Stroud, in accordance to an exemplary embodiment of the invention.

[0027] FIG. 4A illustrates a graphical representation of shear parameters (F) ML soil with standard penetration test (SPT) (N1)60 1-100 of laboratory and existing correlation, in accordance to an exemplary embodiment of the invention.

[0028] FIG. 4B illustrates a graphical representation of comparative analysis of (F) ML soil with SPT (N1)60 1-100 of laboratory and existing correlation and new correlation, in accordance to an exemplary embodiment of the invention.

[0029] FIG. 5 illustrates a graphical representation of correlation for F of ML soil with SPT (N1)60 and 1 to 100, in accordance to an exemplary embodiment of the invention.
Detailed invention disclosure:
[0030] Various embodiments of the present invention will be described in reference to the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps.

[0031] The present disclosure has been made with a view towards solving the problem with the prior art described above, and it is an object of the present invention to provide a method for correlating shear strength parameters of inorganic silt include angle of shearing resistance (F) and cohesion (C) values of ML soils based on corrected Standard Penetration Test (SPT) (N1)60 data.

[0032] According to one exemplary embodiment of the invention, FIG. 1 refers to a flowchart 100 of a method for correlating shear strength parameters of inorganic silt. At step 102, the SPT data (N) test is attains on an allocated region for soil sample. At step 104, collects representative soil samples from the allocated region corresponding to the SPT data. At step 106, performs laboratory tests on the collected soil samples to determine shear parameters (F) and cohesion (C), and plasticity characteristics and calculate SPT (N1)60.

[0033] At step 108, compares the F and C values obtained from the laboratory tests with the values estimated using existing correlations based on the SPT (N1)60 data. At step 110, new correlation equation is developed based on the identified relationship to estimate the F value of an ML soil sample based on its SPT (N1)60 data. At step 112, the newly developed correlation equations is validates using data from additional boreholes within the allocated region.

[0034] According to another exemplary embodiment of the invention, FIG. 2 refers to a flowchart 200 of correlating shear strength parameters of inorganic silt. At step 202, the Standard Penetration Tests (SPT) are conducted at the allocated region to collect data on soil strength in the field. At step 204, soil samples are tested in the laboratory to determine their properties (index and strength characteristics) that influence their behavior. At step 206, the SPT (N1)60 data is calculated from the ML soil. The soil samples are categorized based on a standard system.

[0035] At step 208, measures the shear parameters from the laboratory. At step 210, shear parameters from correlations using SPT (N1)60 is obtained from the step 206. At step 212, the shear parameters from the laboratory tests and compared to the values obtained from correlations for soils under study. The laboratory tests are configured to detect the parameters of the phi value (F) and cohesion (C). At step 214, the phi value (F) is derived from the soil sample using the new correlations and limiting phi values. At step 220, the laboratory test is configured to predict the C values based on the SPT (N1)60.

[0036] At step 216, final graph with SPT (N1)60 and corresponding phi values for ML soils. In one example embodiment herein, the method (Meyerhof's correlation) is used to estimate the Phi value based on the corrected SPT data (N1)60, but only for soil types having fine sand with silt and not in specific for ML soil (used for ML with fines > 5%). At step 218, the validation of developed empirical correlations and guidelines for estimating C and Phi values without relying solely on laboratory data. This new method will likely consider factors like SPT data, soil type based on fines, gravels, clay contents, and aim for better accuracy than existing correlations.

[0037] In one embodiment, the soil samples are tested in the lab to determine their properties (index and strength characteristics) that influence their behavior. The soil samples are categorized based on a standard system (IS 1498) to understand their type. The raw SPT data (N-value) is adjusted to account for various factors that might affect the test results (e.g., soil behavior, testing procedures, and depth). This corrected value is called SPT (N1)60. The actual shear strength parameters (C and Phi) are measured through laboratory tests on the soil samples.

[0038] In one embodiment described herein, the method (Meyerhof's correlation) is utilized to estimate the Phi value based on the corrected SPT data (N1)60. This method is applied exclusively to soil types comprising fine sand with silt and is not specifically intended for ML soil (but also applied for ML with fines > 5%). The existing method (Stroud's correlation) is used to estimate the C value based on SPT (N1)60, but only for certain clay-rich soil types (CL, CI, CH). The estimated C and Phi values from the existing correlations are compared to the actual values obtained from laboratory testing. The soil samples are further grouped based on the percentage of fine particles, gravel, and clay content. The method development is more reliable for estimating C and Phi values without relying solely on laboratory data. This new method will likely consider factors like SPT data, soil type based on fines, gravels, clay contents, and aim for better accuracy than existing correlations.

[0039] In one embodiment herein, the properties of the ML (inorganic silt with low plasticity) soil at the allocated region. The allocated regions include ML (inorganic silt with low plasticity) soil at different depths in boreholes. The allocated region is characterized by alternate layers of coarse and fine grained soils. The properties of soils from the Borehole data collected from the allocated region. Laboratory and field tests are conducted to establish the properties of soil. The properties of ML soil obtained from laboratory tests. Although the ML soil is termed as fine-grained soil, the Phi value (F) is more predominant than the C value, similar to coarse-grained soils.

[0040] In one embodiment herein, the total 13 samples are collected from the allocated regions that are ML soil type samples. The SPT (N1)60 values ranges from 1-100. The field density of soil varies from 14.58 to 19.2 kN/m3. The particle size distribution of samples from laboratory data, ranged as 0 to 5 weight percentage of gravels, 38 to 49 weight percentage of sand, and 51 to 58 weight percentage of silt.

[0041] Table. 1
SL. No Description ML (Inorganic silt)
1 Total No of samples 13
2 SPT (N1) 60 range 3 - 98
3 Density range KN/Cum 14.5 - 19.2
4 Gravel % 0-5
5 Sand % 38 - 49
6 Fines (silt & Clay) % 51 - 58
7 PI index NP-6.7
8 Range of Phi value (F) from lab tests 8 - 34.5
9 Range of Phi value (F) from correlations 28 - 40
10 Range of C value in kPa 0 - 16

(N1)60 : (N1) = Nmeans*CN*CE*CH*CB*CS*CR (1)
(N1)60 = Penetration resistance corrected for both rod energy and for overburden pressure, ?????????? = Measured SPT-‘N’ value at site ???? = Overburden pressure correction factor, ??????????*???? = SPT value corrected for over burden pressure, ???? = Correction factor for effect of energy (e.g. ???? = 0.75 for 45 percent of efficiency of donut hammer), CH = Correction for nonstandard hammer weight or height of fall = ?????? 63.4 ?? 762, H = height of fall of hammer in mm, W = hammer weight in kg, ???? = Correction factor for borehole diameter (???? = 1.05 for 150 mm borehole diameter), ???? = Correction factor for sampling method (???? = 1 for standard sampler) ???? = Correction factor for rod length (???? varies depending on the road length, 0.75 for 3-4m, 0.85 for 4-6m, 0.95 for 6-10m & 1 for 10-30m), a distance of 1.5m is considered between ground level and anvil.

[0042] In one embodiment herein, the comprehensive analysis comparing existing correlations for estimating soil shear strength parameters (C and Phi) with actual laboratory data. The analysis includes tables and graphs for visualization. Additionally, new correlations and guidelines specifically designed for ML soils are introduced. Finally, the developed correlations and guidelines are validated through comparison with data from additional soil samples. The emphasizing the comparison of existing methods, presentation of new methods, and validation of the developed approach.

[0043] According to another exemplary embodiment of the invention, FIG. 3 refers to a graphical representation 302 of the shear strength, plasticity index and SPT N value from Stroud. In one embodiment herein, the accuracy of existing correlations for estimating soil shear strength parameters cohesion (C) and angle of shearing resistance (F) in the allocated region. The correlations utilize SPT (N1)60 values, and their estimated values are compared with those obtained from laboratory tests.

[0044] The analysis is conducted to assess the reliability of these correlations within the specific context of the allocated region. Additionally, new correlations tailored to this region are developed based on the laboratory test results. Phi value (F) is calculated specific to this location are developed based on the results of the laboratory tests.
F = 25 + 0.15 Dr (%) for granular soil with more than 5 percent of fine sand and silt (2)
F = 30 + 0.15 Dr (%) for granular soil with less than 5 percent of fine sand and silt (3)
where Dr is relative density,
Dr (%) = 100 X (SQRT(N1)60/60) (4)
The correlations for fine grained soils Stroud (1975) has established empirical correlations between SPT N value and un-drained shear strength.
Cu (kPa) = f1 N60 (5)
where,
f1 = factor depending on plasticity index,
N60 = SPT N value corresponding to 60 percent of hammer efficiency.

[0045] In one embodiment herein, the existing Meyerhof's (1956) correlation (Equation 2) is used to estimate the Phi value (F) for soil samples. While Stroud's (1974) correlation (Equation 5) is generally used for estimating the cohesion (C) value, it's not as reliable for ML soils where Phi (F) is more dominant. Therefore, this study developed specific guidelines for estimating C values in ML soils based on SPT (N1)60 data and the clay percentage of the samples. The analysis of soil data, including tables and graphs for each soil type, investigated the influence of grain size distribution, density, and plasticity index on the shear parameters of ML soils. The results presented below include comparisons between laboratory data, existing correlations, and regression analysis through plots and graphs.

[0046] According to another exemplary embodiment of the invention, FIG. 4A refers to a graphical representation 402 of the shear parameters (F) ML soil with standard penetration test (SPT) (N1)60 1-100 of laboratory and existing correlation. In one embodiment herein, the x-axis of the shear parameter Phi (F) represent the angle of shearing resistance of the soil. The key parameter for assimilating soil ability to resist shear stress before failure. The higher phi value (F) resistance to shearing. In one embodiment herein, the x-axis of SPT (N1)60 values is configured to corrected standard penetration test results, which account for factors like overburden pressure and equipment efficiency. Higher SPT (N1)60 values indicate a denser or stiffer soil.

[0047] In one embodiment herein, FIG. 4A, the data points include laboratory data (scattered circles), correlated data (triangle markers), one possible correlation (blue triangle markers). The laboratory data is configured to represent the Phi (F) values measured directly through laboratory tests on the ML soil samples. The correlated data is configured to represent the Phi (F) values estimated using existing correlations based on the SPT (N1)60 values. From the limited data shown, two correlation lines seem to be plotted.

[0048] The one possible correlation is appears to show a generally increasing trend with SPT (N1)60 values. The possible correlation might exhibit a different relationship, but it's difficult to discern the exact trend from the limited data shown. In one embodiment herein, the regression analysis (red line with equation) is configured to fit through the laboratory data points, potentially representing a statistical trend for Phi value (F) based on the actual measurements. The equation for this line is provided next to the graph (y = 1.24286e0.1175x) and might be a linear regression equation.

[0049] In one embodiment herein, the key observation of the graph. The data points for laboratory measurements (circles) show some scatter, suggesting some variability in the Phi values even for a specific SPT (N1)60 value. There appears to be general upward trend for phi (F) value with increasing the SPT (N1)60 value, indicating that denser ML soils tend to have higher angles of shearing resistance. The graph suggest that while existing correlations might provide an estimate of Phi value (F) for ML soils based on SPT (N1)60 value, they may not perfectly match the actual values obtained through laboratory testing. The research described in the patent aims to develop improved methods for estimating Phi values (F) specifically for ML soils in a particular region.

[0050] According to another exemplary embodiment of the invention, FIG. 4B refers to a graphical representation 404 of the comparative analysis of Phi value (F) ML soil with SPT (N1)60 1-100 of laboratory and existing correlation and new correlation. In one embodiment herein, the existing correlation (series 1) data points represent the phi values estimated using an existing correlation, likely Meyerhof’s correlation (equation 2) mentioned. The new correlation (series 2) data points represent the phi values estimated using a new correlation developed in this research, specifically for ML soils in the study area. The laboratory test (series 3) data points represent the Phi value (F) values directly measured through laboratory tests on the ML soil samples.

[0051] In one embodiment, the three series of data points are plotted against the SPT (N1)60 values ranging from 1 to 100 on the x-axis. The higher SPT (N1)60 value indicate denser or stiffer soil. The y-axis represent the shear parameter Phi value (F), which signifies the angle of shearing resistance of the soil. The higher F value indicates a higher resistance to shearing stress.

[0052] In one embodiment, the observation from the graph include general trend, and comparison of methods. The general trend appears to be general upward trend for Phi value (F) value with increasing the SPT (N1)60 values for all three data series, which indicates that denser ML soils tend to have higher angles of shearing resistance, regardless of the method used to estimate the Phi value (F).

[0053] In one example embodiment, the visually comparing the data points, the new correlation (red points) seems to follow the trend of the laboratory data more closely than the existing correlation across the range of the SPT (N1)60 values. The newly developed correlation might provide a more accurate estimate of the Phi value (F) for ML soils in this specific region compared to the existing correlation.

[0054] According to another exemplary embodiment of the invention, FIG. 5 refers to a graphical representation 502 of the correlation for Phi value (F) of ML soil with SPT (N1)60 from 1 to 100. In one embodiment herein, the x-axis represent the SPT (N1)60 values that are configured to standard penetration test results, which account for factors like overburden pressure and equipment efficiency. The higher SPT (N1)60 values indicate a denser or stiffer soil. The y-axis (shear parameter - Phi value (F)) that is configured to angle of shearing resistance of the soil. The key parameter for understanding a soil’s ability to resist shear stress before failure. The higher phi value (F) indicates a higher resistance to shearing.

[0055] In one embodiment herein, the data series (red line) represents the phi value estimated using the new correlation developed in the research for ML soils. The equations for the new correlation is displayed on the graph (y = -0.0033x² + 0.4854x + 17.267). This is a quadratic equation, where x represents the SPT (N1)60 value and y represents the estimated Phi value (F).

[0056] Table. 2
(N1)60 (1) Density (kN/m3) Gravel (%) Sand (%) Silt Clay Lab Phi value (2) Correlation Phi value (3) Error (%) Modified/New correlation Phi value (4) % Error after correction Lab C value C value obtained from analysis
98 19.2 5 38 57 34 40 17.65 34 0.00 0 0
90 18 0 45 55 33.5 40 19.40 34 1.49 0 0
97 18.6 0 49 51 34.5 40 15.94 34 -1.45 0 0
11 17.3 3 41 49 7 17 31 82.35 22 27.65 9 10
26 16.84 2 47 51 23 34 47.83 27 18.26 10 10
30 18.01 2 40 51 7 31 35 12.90 30 -4.03 6 10
47 18.01 2 45 43 10 33 38 15.15 32 -2.12 0 0
64 18.01 4 41 55 0 33 40 21.21 34 3.03 0 0
64 18.01 0 43 51 6 33 40 21.21 34 3.03 0 0
15 17.21 2 40 53 5 29 32 10.34 26 -11.72 0 5
29 17.7 1 42 57 0 27 35 29.63 28 3.70 8 5
Avg error (%) 26.6 Avg error (%) after error 3.44

[0057] In one embodiment, the new correlation shows a curved relationship between SPT (N1)60 value and phi value (F). The Phi value (F) is configured to increase at a slightly decreasing rate as SPT (N1)60 value increase. The additional information (R2 = 0.9623) that value represent the coefficient of determination and indicates a proper fit between the data used to develop the new correlations and the corresponding equation. However, the value necessarily reflect to the new correlation predicts Phi value (F) for unseen data.

[0058] The graph of correlation for Phi value (F) of ML soil with SPT (N1)60 value and 1 to 100 suggests the new correlation is application for SPT (N1)60 value ranging from 1 to 100. The graph depicts the new correlation between SPT (N1)60 value and F value for ML soils. While the high R-squared value suggests a good fit for the data used to develop the correlation, further validation with real-world data is necessary to assess its accuracy in predicting Phi value (F) for ML soils at the allocated region.

[0059] Numerous advantages of the present disclosure may be apparent from the discussion above. In accordance with the present disclosure, a method for correlating shear strength parameters of inorganic silt with low compressibility is disclosed. The proposed method treats the inorganic silt with a clay percentage for precise determination of the shear strength, and cohesion. The method provides more reliable estimates of the soil actual shear strength, making it safer and more cost-effective.

[0060] The proposed method enhances the accuracy of shear strength estimations by considering the clay content within the inorganic silt, leading to more reliable predictions. The proposed method enhances the safety and cost-effectiveness of foundation design in an allocated region by providing engineers with more accurate data on soil capacity. The proposed method correlates F and C values based on the clay percentage within the ML soil, comparing laboratory test results with existing correlations.

[0061] The proposed method estimates the correlation by aiming for around a 10 percent error margin for C and F values compared to the new correlation. The proposed method provides a more reliable method for assessing the shear strength of inorganic silt in the allocated region, contributing to a safer and more economical foundation for infrastructure projects. The proposed method that estimated errors for both parameters are expected to be within a range, offering a significant improvement over existing methods that often lead to overestimations.

[0062] It will readily be apparent that numerous modifications and alterations can be made to the processes described in the foregoing examples without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this application.
, C , Claims:CLAIMS:
I/We Claim:
1. A method for correlating shear strength parameters of inorganic silt with low compressibility (ML) Soil, comprising:
attaining corrected standard penetration test (SPT) data (N) on an allocated region for soil sample;
collecting representative soil samples from the allocated region corresponding to the SPT data;
performing laboratory tests on the collected soil samples to determine shear parameters (F) and cohesion (C), and plasticity characteristics and calculate SPT (N1)60;
comparing the Phi value (F) and ‘C’ values obtained from the laboratory tests with the values estimated using existing correlations based on the SPT (N1)60 data;
developing a new correlation equation based on the identified relationship to estimate the Phi value (F) of an ML soil sample based on its SPT (N1)60 data; and
validating the newly developed correlation equations using data from additional boreholes within the allocated region.
2. The method as claimed in claim 1, wherein the step of developing guidelines for determining the cohesion (C) value of the ML soil sample based on the clay content.
3. The method as claimed in claim 2, wherein the guidelines for determining the ‘C’ value include a relation between clay content and a pre-defined range of C values.
4. The method as claimed in claim 1, wherein the existing correlations used for comparison include Stroud's correlation for cohesion (C) and Meyerhof's correlation for the angle of shearing resistance (F).
5. The method as claimed in claim 1, wherein the new correlation equations are configured to estimate the Phi value (F) and ‘C’ values with an error margin of around 10 percent compared to the laboratory determined values.
6. The method as claimed in claim 1, wherein the method is assessing the soil resistance properties using corrected SPT N values by correction of overburden pressure at a deeper depth and correction of saturated fine sand and silts.
7. The method as claimed in claim 1, wherein the laboratory test conducted on the collected soil samples to determine natural moisture content, dry unit weight, specific gravity, and grain size analysis.