Static Cone Penetration Test Research Articles

Elasto-plastic solution for undrained cylindrical cavity expansion in refuse soil

To address geotechnical engineering issues such as pile driving, lateral pressure tests, and static cone penetration tests on increasing number of infrastructure projects being constructed on landfills, an elasto-plastic theoretical solution for the undrained cylindrical cavity expansion in refuse soil is proposed in this paper based on an elasto-plastic constitutive model for refuse soil considering the reinforcement effect of fibers, along with a large deformation theory. The correctness of the results is validated through comparison with existing solutions based on the modified Cam-clay model. The results indicate that the response of columnar pore expansion in refuse soil is significantly different from that in ordinary soil. Near the pore, refuse soil does not enter a critical state, only the slurry-like components do. Subsequently, the reinforcement effect of the fiber material begins to manifest. Refuse soils with different fiber contents undergo both elastic and plastic stages before reaching the critical state line of the slurry-like components in the soil. They then move a certain distance along this line to reach a maximum. Given the rarity of engineering construction on similar sites in the past, the unique response of refuse soil during cylindrical cavity expansion should be given special attention.

GEOTECHNICAL INVESTIGATIONS FOR SCHOOL CONSTRUCTION

A series of earthquakes that commenced on December 28, 2020, resulted in extensive material damage within a 50-60 km radius from the epicenter, located near the City of Petrinja. Due to the significant structural damage sustained by the building of Petrinja Primary School I, a decision was made to construct a new school building. The construction of the new school began in 2022 and was completed in 2023. This study presents the findings of geotechnical investigations conducted at the site of the new school, which included five static cone penetration tests (CPTu), two dynamic probing heavy tests (DPH), one Marchetti dilatometer test (DMT), and two profiles of multi-channel analysis of surface waves (MASW). The geotechnical investigations resulted in the development of a soil profile consisting of eight distinct zones. Recommendations for the foundation design of the new building have been provided, alongside an assessment of the risk of soil liquefaction. The potential for liquefaction has been identified within zone 4, which comprises clayey sands at depths ranging from 4 to 6 meters.

Influence of Correlation Distance of Soil Parameters on Pile Foundation Failure Probability

Spatial variability of soil parameter distribution is crucial to calculating the pile foundation failure probability. Traditional reliability design methods describe the dispersion degree of soil parameters with their point variance without considering the influence of correlation distance. In this paper, static cone penetration test data of a project site are used, and random field theory is introduced to describe the average spatial characteristics of soil parameters. Then, the method of spatial average is used to calculate the correlation distance of soil parameters in each foundation soil layer. Given the influence of the correlation distance, a variance reduction function is determined to convert point variance to spatial mean-variance and further calculate the failure probability of pile foundation with the Monte Carlo method to study the influence of correlation distance on pile foundation failure probability. Results show that the spatial variability of parameters can be better reflected, and project cost can be reduced by considering the influence of correlation distance during the pile foundation design process. These results lay a foundation for further research on the pile foundation reliability design method.

Heavy vibratory plate compaction of silty sand: A field study

Heavy vibratory plate compaction is an efficient technique for improvement of granular soils. However, its practical application is limited by insufficient knowledge about the compaction process and the optimum procedure of execution. In this study, compaction tests were conducted in the field with a 40.5-ton heavy vibratory plate compactor. The site consisted of partially saturated, overconsolidated medium-dense silty sand and sandy silt. Such conditions can generally be characterized as difficult for vibratory compaction. The objective of the tests was to study the compaction depth and the influence of treatment layout, duration of compaction, and vibration frequency. In-situ measurements conducted before, during and after treatment included static cone penetration tests, flat dilatometer, and heavy dynamic probing. The in-situ tests showed a statistically significant compaction after treatment. The main conclusions highlight the importance of a sufficient centrifugal force of the vibratory hammer to cause disconnection between the plate and the soil. Other important parameters are the vibration frequency and the duration of treatment, which can be optimized by field monitoring. Full coverage of the ground surface is required for compaction of the entire soil volume. It was also found that the compaction depth corresponds to the side length of the plate, in line with previous studies.

Spatially Distribution of Soil Ultimate Bearing Capacity at Singkil-Aceh Based on a Static Cone Penetration Test

The Singkil Sub-district of Aceh Singkil District comprises alluvium deposits with a relatively low ultimate bearing capacity. The ultimate bearing capacity of the soil is closely related to the safety of a building. The important thing related to estimating the ultimate bearing capacity of the soil is in-situ soil investigation. This study aims to estimate the spatial distribution of soil ultimate bearing capacity using field test data in the Singkil Sub-district. Estimating ultimate bearing capacity is useful to provide an initial picture for various planning and infrastructure development activities in the study area. Twenty CPT in-situ tests have been obtained from various field works in Aceh Singkil Regency. Field data analysis, based on empirical methods, was carried out to obtain the value of the ultimate bearing capacity of the soil at the test location. Then, the estimated distribution of the maximum bearing capacity obtained was carried out. The zoning map of the distribution of soil ultimate bearing capacity in the study was developed from this research. This map can be used as a form or effort of disaster mitigation by various stakeholders involved in planning and building various infrastructure facilities in the Singkil Sub-district

Energy balance analyses during Standard Penetration Tests in a virtual calibration chamber

The Standard Penetration Test (SPT) is the most popular example of dynamic probing, a large category of soil testing techniques. Understanding and interpretation of these tests is hampered by the difficulties of reproducing them under controlled laboratory conditions. The virtual calibration chamber technique, based on the Discrete Element Method (DEM), may supplement or substitute this complex experimentation. In this paper SPT in sand are analyzed considering the energy transfer involved. Energy balances are written for the penetrating rod and for the material in the chamber. All the terms are computed for a number of cases in which the main variables controlling test response in the field -initial density and stress level- are systematically varied. The analysis confirms previous field observations indicating that, when an energy-based interpretation is used, SPT provides a value of equivalent penetration resistance that is the same that would be obtained with a static cone penetration test. The analyses also provide an unequivocal explanation for this observation: although the impacting rod shows complicated dynamics the response of the sand is quasi-static.

Estimating bearing capacity using static cone penetration test at Banda Aceh area (northern tip of Sumatra)

The static cone penetration test (s-CPT), or better known in Indonesia as the sondir, has been used as a soil investigation procedure since nearly half a century ago in Europe, especially in the Netherlands and Belgium. This s-CPT is one of the standard practices in soil investigation campaigns and can provide many soil engineering parameters, including soil bearing capacity. This study focuses on the soil bearing capacity analysis in the city of Banda Aceh on the data taken from the 35 points of s-CPT. The analysis of the soil bearing capacity at a depth of 1.4 meters and 2.4 meters below the existing ground level (mbgl) was carried out. Dominantly, at a depth of 1.4 mbgl at the research location, it has a low bearing capacity (<2.5 tons/m2) with a percentage of 91.43%. There are 2.86% for bearing capacity from 2.5 to 5 tons/m2, from 5 to 7.5 tons/m2, and from 7.5 to 10 tons/m2. No soil layer had a bearing capacity above 10 tons/m2. At a depth of 2.4 mbgl, the research location has a low bearing capacity (<2.5 tons/m2) with a percentage of 48.57%, for bearing capacity ranging from 2.5 to 5 tons/m2 is 17.14%, for bearing capacity of 5 to 7.5 tons/m2 is 2.86%, for bearing capacity of 7.5 to 10 tons/m2 of 5.71% and bearing capacity above 10 tons/m2 is 25.71%.

Mapping of the depth of hard/dense layer at Banda Aceh-Indonesia and the surrounding areas

The 26 December 2004 disaster caused enormous casualties and damages in affected regions. Indonesia suffered a loss of 42.7 trillion Rupiah. On the other hand, this disaster has raised awareness among some people to carry out construction following engineering principles, so that the newly constructed buildings have an adequate level of safety. A hard/dense soil layer has a close relationship with the safety level of a building. This paper proposes a map of the depth of hard/dense (stable) layer at one of the worst affected cities, i.e., Banda Aceh (Indonesia) of the boxing day 2004 disaster. A static cone penetration test (CPT) was employed to determine the depth of stable soil. The data from the 35 cone penetration tests were used to develop the zoning map of the depth of the stable soil in the study location. The dominant hard/dense soil depth in the study location is > 10 meters below the existing ground level. In certain places, such as the areas around Lambung, Neusu Aceh, Lambaro Skep, Jeulingke, Doi, Kopelma Darussalam, and Lamjame, the depth of stable soil is from 5 to 10 meters.

Evaluation of Ultimate Bearing Capacity of Pre-Stressed High-Strength Concrete Pipe Pile Embedded in Saturated Sandy Soil Based on In-Situ Test

Estimation of ultimate bearing capacity (UBC) of pre-stressed high-strength concrete (PHC) pipe pile is critical for optimizing pile design and construction. In this study, a standard penetration test (SPT), static cone penetration test (CPT) and static load test (SLT) were carried out to assess, determine and compare the UBC of the PHC pipe pile embedded in saturated sandy layers at different depths. The UBC was calculated with three methods including the JGJ94-2008 method, Meyerhof method and Schmertmann method based on in-situ blow count (N) of SPT (SPT-N) which was higher than the values recommended in survey report regardless of pile length. The average UBC values calculated with cone-tip resistance and sleeve friction from CPTs was also higher than the value recommended in the survey report. Moreover, the actual UBC values directly obtained by load-displacement curves from SLTs were in line with the calculated values based on in-situ SPTs and CPTs, but approximately twice as high as the values recommended in the survey report regardless of pile length. For the SPT method, the application of bentonite mud in saturated sand layers is critical for the assessment of pile capacity in the survey phase, CPTs can provide reliable results regardless of soil characteristics and groundwater if the soil layer can be penetrated, and SLTs are necessary to accurately determine the UBC in complex stratum.

Deformational Assessment of Shallow Footings Founded on Carbonate Sand

Carbonate (calcareous) sandy soils are well known to be prone to crushability and to have higher compressibility compared to siliceous sands. This study assess the deformational behavior of carbonate (calcareous) sand under shallow footings by carrying out back analyses load tests of twelve full-scale footings founded on improved carbonate (calcareous) sand fill and uniformly loaded up to the allowable bearing pressure. The footings are reinforced concrete isolated pads ranging from 1.5×1.5 m up to 3×3 m in size. These full-scale loading tests are combined with extensive in-situ static cone penetration tests carried out under the location of each footing to test the foundation soil. The recoded measurements of these full-scale load tests are utilized to measure the immediate settlements of the sand fill under variable stresses and to extrapolate long-term (creep) settlement as wells. Based on the analyzed results, comprehensive back analyses were carried out to validate several commonly-used settlement prediction formulae, including Schmertmann’s method (Schmertmann et al., 1978) and Meyerhof (1965 and 1974) for utilization validation with carbonate (calcareous) coarse-grained materials.

Shear Wave Velocity in the East Nile Delta Clay: Correlations with Static CPT Measurements

The East Port Said region, one of the most vibrant areas in the East Nile Delta, is a strategic economic zone that is receiving growing local and global investments. The near surface formations, however, typically comprise very soft clays deposited during the Holocene epoch. Collecting undisturbed samples and conducting laboratory evaluation of these sensitive soils could be cumbersome, inaccurate, and uneconomical. Therefore, the use of in-situ cone penetration test (CPT) provides a viable and convenient characterization alternative. This study attempts to establish site-specific correlations between the measurements of the static CPT and shear wave velocities (Vs) furnished by seismic piezocone soundings. The mathematical regressions were developed utilizing a number of measurements and factors, namely, tip resistance, sleeve friction, effective stress, depth, voids ratio, and soil behavior type index. The proposed correlations demonstrate different levels of predictability, with a few warranting confidence in employing static CPT for estimation of Vs profile in this region. Two correlations, one utilizing void ratio and tip resistance and the other employing sleeve friction solely, have shown to provide the most reliable Vs predictions for the soft clay in the East Nile Delta.

Geoelectric versus MASW for geotechnical studies

We explore the role of non-invasive multi-electrode electrical resistivity imaging (ERT) and induced polarisation imaging (IPI) as an alternative to multichannel analysis of surface waves (MASW) for geotechnical site characterisation in view of their higher near-surface spatial resolution. By using regression equations, we assess the relative performance of ERT, IPI and MASW in predicting geotechnical test results (standard penetration test (SPT), dynamic cone penetration test (DCPT) and static cone penetration test (SCPT)) in a site investigation on our IIT Roorkee Campus, India. The results indicate that the average root mean square (RMS) errors in predicting SPT based on ERT, IPI and MASW are 16.95%, 21.9% and 28.03%, respectively. Likewise, the average RMS errors in predicting DCPT based on ERT, IPI and MASW are 15.4%, 15.3% and 56.99%, respectively, and the average RMS errors in predicting SCPT based on ERT, IPI and MASW are 20.15%, 18.65% and 36.49%, respectively. In view of higher resolution for near-surface investigations, ERT/IPI seems to score over MASW in geotechnical site investigation studies. So, a leading role for non-invasive and cost-effective ERT/IPI in geotechnical site investigations is envisaged.

Influence of coarse particles on the physical properties and quick undrained shear strength of fine-grained soils

Soils are generally classified as fine-grained or coarse-grained depending on the percentage content of the primary constituents. In reality, soils are actually made up of mixed and composite constituents. Soils primarily classified as fine-grained, still consists of a range of coarse particles as secondary constituents in between 0% to 50%. A laboratory scale model test was conducted to investigate the influence of coarse particles on the physical (e.g., density, water content, and void ratio) and mechanical (e.g., quick undrained shear strength) properties of primarily classified fine-grained cohesive soils. Pure kaolinite clay and sand-mixed kaolinite soil (e.g., sand content: 10%, 20%, and 30%) having various water contents (60%, 65%, and 70%) were preconsolidated at different stress levels (0, 13, 17.5, 22 kPa). The quick undrained shear strength properties were determined using the conventional Static Cone Penetration Test (SCPT) method and the new Fall Cone Test (FCT) method. The corresponding void ratios and densities with respect to the quick undrained shear strength were also observed. Correlations of the physical properties and quick undrained shear strengths derived from the SCPT and FCT were also established. Comparison of results showed a significant relationship between the two methods. From the results of FCT and SCPT, there is a decreasing trend of quick undrained shear strength, strength increase ratio (Su/Po), and void ratio (e) as the sand content is increased. The quick undrained shear strength generally decreases with increased water content. For the same water content, increasing the sand content resulted to a decrease in quick undrained shear strength due to reduced adhesion, and also, resulted to an increase in density. Similarly, it is observed that the change in density is distinctively noticeable at sand content greater than 20%. However, for sand content lower than 10%, there is minimal change in density with respect to water content. In general, the results showed a decrease in quick undrained shear strength for soils with higher amounts of sand content. Therefore, as the soil adhesion is reduced, the cone penetration resistances of the FCT and SCPT reflects internal friction and density of sand in the total shear strength.

Geo-engineering properties of Eemian peats from Radzymin (central Poland) in the light of static cone penetration and dilatometer tests

The paper presents the results of field studies testing the reaction of Eemian peats on the mechanical effect of standard measurement tools (CPT/CPTU, Marchetti dilatometer). Based on the collected undisturbed samples, macroscopic observations were made and SEM observations were conducted to identify the microstructural features. A fibrous structure and advanced diagenetic changes have been noted in the studied peats despite their relatively young age. These may have resulted from an exceedingly strong structural reinforcement, which causes that the studied sediments cannot be treated as low-bearing soils. Diagenetic processes caused farfetched changes of the mechanical properties, which is reflected e.g. in classification normograms. Standardized diagrams may lead to false conclusions. The presented studies of organic soils are an example of strong influence of structural features and diagenetic phenomena on the results obtained for native soils. At the same time, they imply particular caution in the interpretation of the substratum properties based only on the commonly used in situ tests. The values and variability of the collected parameters have been presented as frequency distributions. Additionally, the apparent character of the properties of preconsolidation parameters (OCR) has been shown.

Field experimental study on prestressed concrete tube-pile bearing stratum softening in strong weathered rock formation of Shunde area

In the Foshan Shunde District, for the bearing stratum of the prestressed concrete tube-pile in strong weathering granite gneiss and strong weathering silty mudstone, it is common for abnormal setting of static load test and ultra pile driving in re-pressed process. There is no unified explanation and exact conclusion on whether this problem is caused by softening of pile-end soils. In order to solve this problem, experiments for piles with different pile tip were conducted for evaluate the changing of strength, horizontal stress and bearing capacity of pile-end soils, using various situ techniques such as static cone penetration test, pressure meter test, high strain testing and static load test combined with laboratory test results. It implies that strong weathering granite gneiss and silty mudstone in Shunde area has softening potential, however, the softening of pile-end soils may not occur immediately after piling. In addition, the effect of type of pile tip on the bearing capacity of the bearing stratum was not obvious. According to this study, it was suggested that engineering investigation should be given attention to. This study will have important implications for determining the bearing capacity of pile and guaranteeing the project quality.

Comparison of geotechnical uncertainties linked to different soil characterization methods

ABSTRACTOne of the essential inputs in settlement prediction models is the soil modulus, which may be obtained from laboratory tests or estimated from in situ measurements. The total uncertainty in predicting the confined modulus of a sandy soil is quantified with data from side-by-side in situ testing using the standard penetration test, the static cone penetration test, the light dynamic probing and the laboratory oedometer test. To estimate transformation errors, correlations are proposed between in situ and laboratory data. The results indicate that similar magnitudes of total uncertainties are associated with the in situ methods, which are approximately twice as high as those from the direct oedometer method. The quantified uncertainties are an important input for reliability-based designs of foundations under similar soil conditions.

Large Deformation Finite Element Analysis of Static Cone Penetration Test

Present work includes simulation of field static cone penetration test (SCPT) using three dimensional elastoplastic finite element analysis. The coupled Eulerian–Lagrangian (CEL) technique available in finite element software Abaqus/Explicit is used to simulate the experimental SCPT. The soil stress–strain response has been simulated using the Mohr–Coulomb constitutive model. The cone is modeled as a rigid body in the simulations. The results of CEL simulations have been compared with the laboratory results, field test results and numerical results in an attempt to understand the capability of CEL technique in simulating SCPT and in characterizing soil behavior numerically through large deformation finite element procedure. It is observed that CEL can successfully simulate cone penetration tests which in turn, facilitates in characterizing soil stress–strain response.

Study on relationship between static cone penetration strength and shear strength of soil

On basis of the analysis on results of laboratory test, the field vane shear test and the static cone penetration test of different types of soil in Tianjin, it is proposed that there is significant positive linear correlation between the static cone penetration tip resistance and the vane shear strength. Moreover, for clay a more distinct linear correlation exists than that for mucky soil and silty clay. Therefore the results of static cone penetration test can be applied to the stability calculation.

Design parameters of nondisplacement pile in sand

The paper deals with an experimental investigation of design parameters for nondisplacement pile in sand. The study was envisaged to find out the influence of stress level on the parameters like Nq, δ, Kstan δ, etc. by performing laboratory tests on a steel pile buried in sand bed. In one set, the sand bed was subjected to controlled vertical stress, and in another set, controlled horizontal stress was applied. Density of sand was varied, and different stresses were applied to evaluate point bearing, shaft friction, and total capacities. The parameters required to predict the axial capacity of pile have been found to vary with stress applied on the sand bed. However, at higher stress range, the values have shown tendency to attain constant magnitude. The parameters at higher stress range have been found to tally more or less with those used in general engineering practice. A factor, friction ratio, which is generally used in interpreting static cone penetration test data, has been found to be about 2%.

The Test Analysis of the Bearing Capacity of Foundation

The test method of shallow plate load was used in the bearing capacity of foundation of Yushu City , doing two groups of loading test in different depths and doing survey and comparative test between test point nearby and sites in the same horizon.It gets the law of foundation soil bearing capacity value got by different test methods and provides the basis for Jilin Province to establish the local standards through the comparison of load test and geotechnical test , static cone penetration test and standard penetration test.