Test CPT Research Articles

Fast Lagrangian analysis of the short-term bearing capacity of shallow foundations in clays on the basis of the cone penetration test

Based on a numerical modelling of the cone penetration test CPT as well as the vertical response of shallow foundation in saturated clays, derivation of the cone factor Nk led to propose a CPT-based method of computation of the bearing capacity. This study was carried out by launching a detailed parametric study using the software FLAC-2D (Fast Lagrangian Analyses of Continua) based on the finite difference method. The soil material was modeled as a homogeneous elastic-perfectly plastic medium obeying the Mohr-Coulomb criterion, and the effects of the soil rigidity index Ir, the cone-soil interface, and the initial depth of the penetration on the cone factor Nk were investigated leading to an analytical formulation of Nk. After a comparative study with those proposed in the literature, the cone factor Nk was used to derive the bearing capacity factor Kc of a shallow foundation. Compared to current CPT-based methods proposed in the literature, this method reasonably predicts the short-term bearing capacity of shallow foundations in saturated clayey soil.

Evaluating Differences in Foundation Depth Planning and Implementation for Building Structure Safety

Kediri has been named the Most Sustainable City. To support this, Kadiri University also contributed by building lecture buildings. In its implementation, there is a difference in the depth of the foundation from the initial plan. This causes the need for evaluation to ensure the safety of the building structure. This research aims to identify (Cone Penetration Test) CPT distances, depth differences, negative skin friction, settlement, and empirical bearing capacity calculations on the safety of building structures on sandy soil. The direct observation method was used to obtain data. The analysis includes a comparison of depth, negative skin friction values, settlement, and bearing capacity. The research results show that the average CPT distance is 18.22 m, which can result in inaccurate CPT data because differences in soil structure can occur. A depth difference of 22% from the plan can be considered safe for the structure. This is validated by a field settlement of 2 mm lower than the maximum settlement limit and a Negative skin friction value of 0, indicating no additional settlement. These parameters indicate that the structure is safe. The modified Meyerhoff and Trofimankove methods are suitable for planning foundations with sandy soil because they can meet the load received. This research can add empirical evidence in evaluating structural safety for different depths of foundation planning and implementation in sandy soil-based projects, as well as reducing the potential risk of structural failure in the long term.

Predicting the bearing capacity of pile installed into cohesive soil concerning the spatial variability of SPT data (A case study)

Nowadays, in situ tests have played a viable role in geotechnical engineering and construction technology. Besides lab tests conducted on undisturbed soil samples, many different kinds of in-situ tests were used and proved to be more efficient in foundation design such as pressuremeter PMT, cone penetration test CPT, standard SPT, etc. Among them, a standard penetration test (SPT for short) is easy to carry out at the site. For decades, it has proved reliable to sandy soil, but many viewpoints and opinions argued that the test was not appropriately applicable to cohesive soil because of scattered and dispersed data of SPT blow counts through different layers. This paper firstly studies how reliable the SPT data can predict the physical and mechanical properties; secondly, the soil strength is determined in terms of corrected N-SPT values, and finally the bearing capacity of a pile penetrating cohesion soil. By analyzing data from 40 boreholes located in 18 projects in Ho Chi Minh City, South VietNam, coefficients of determination between SPT numbers and physical and mechanical properties of different soil kinds are not the same: R2 = 0.623 for sand, =0.363 for sandy clay and =0.189 for clay. The spatial variability of soil properties is taken into account by calculating the scale of fluctuation θ=4.65m beside the statistically-based data in horizontal directions. Finally, the results from two theoretical approaches of predicting pile bearing capacity were compared to those of finite element program Plaxis 3D and static load test at site. Correlation between the capacity computed by using corrected N-values instead of soil strength and results of static load test has proved to be well suitable in evaluating the bearing capacity of driven and jack-in piles, particularly installing in the cohesive soil using the SPT blows.

Comparison of Interpretation Between CPT and Res-2d Methods for Geostratigraphic Profiling Determination of Kota Depok

In its simplest application, the cone penetrometer offers a quick, expedient, and economical way to profiling a subsurface soil layering at a particular site. No drilling, soil samples, or spoils are generated, therefore, cone penetration test CPT is less disruptive from an environmental standpoint. The continuous nature of CPT reading permits clear delineations of various soil strata, their depths, thicknesses, and extent, perhaps better than conventional rotary drilling operations that use a standard drive sampler at 5-ft vertical intervals. The cone penetrometer is instrumented with load cells to measure point stress and friction during a constant rate of advancement. The results can be interpreted within different theoretical frameworks or by using empirical methods, or both. RES-2D (resistivity – two dimension) completed by Geoscanner devices is applicable to interpret the soil profiling from soil exploration works. Generally, the geoscanner is used to assess the geological subsurface condition for mining works. This paper is addressed to compare the results for soil classification in Kota Depok, West Java using a cone penetration test and RES-2D. From both methods, the result of soil strata shows the soft soil in study area can be classified as clay layers from ground surface to the depth of 15.0 m. However, the CPT is less applicable to measure exactly the elevation of ground water table than RES-2D. In addition, RES-2D is also less applicable to predict the soil properties of the soil type than CPT. In general application, both devices can be applied to soil investigation for geotechnical works.

Análisis experimental de la anestesia/analgesia hipnótica (A/AH): una propuesta interconductista.

According to a interbehavioral perspective, in a previous work it was presented a model to analize Hipnotic Anesthesia/Analgesia (HA /A) as a phenomenon of Paradoxical Stable Affectation (PSA), possibly belonging to a case of Referential Sustitutive Function. In order to analyze empirically how the referents “hypnosis” and “relaxation” involved in the same form of procedure (or “hypnotic induction”) can facilitate or interfere with the articulation of the HA/A, a methodology is used to identificate Verbal Indicators (VI) and Nonverbal Indicators (NVI) related to pain. For the present study Test Pressure Cold or CPT was used. The results showed that the use of reference “hypnosis” can facilitate the disappearance of the NVI and a decrease of VI, while in the case of reference “relaxation” NVI and VI reduce but none disappear.

Collaborative progress test (cPT) in three medical schools in Indonesia: The validity, reliability and its use as a curriculum evaluation tool

Background: Three medical schools in Indonesia have been collaborating in evaluating the learning process in the current curriculum by administering a collaborative progress test (cPT). The 120 multiple choice questions for cPT was developed by the three schools. This study aimed to assess the validity and reliability of the cPT as a part of curriculum evaluation.Method: The cPT was administered to year 1–5 students. A stratified random sampling based on the student Grade Point Average (GPA) was performed. The construct validity was established by assessing the accordant increase of mean score of cPT to the student year level. Finally, the reliability of the cPT was calculated using Cronbach Alpha coefficient.Result and discussion: A total of 223, 219 and 161 year 1 to 5 students completed the cPT in FM UI, FM UNAND, and FM UNS, respectively. The content and construct validity of the cPT were evident. There was an increase of the mean score from year 1 to 5, either in the pooled data (one way ANOVA F 174.7(4), p < 0.001) and in each school (one way ANOVA FMUI F 102.5 (4) p < 0.001, FM UNAND F 83.0 (4) p < 0.001, FM UNS 28.28(4) p < 0.001). The internal consistency of the cPT was very good in the three institutions.Conclusion: The cPT was proven to be a valid and reliable test to measure the increase of knowledge of medical students and was also useful to provide feedback for curriculum evaluation in the three medical schools. Further improvement is required in assuring the test blueprint and the content of the test items.

Simulation and Springback Prediction of Integral Panel with High Ribs in Age Forming

Age forming is the best forming method of integral panel parts of aircrafts, which have large amount of springback and the springback’s accuracy, is hard to control, so a method which can make an accurate prediction of the springback after forming is needed. This article which is based on creep test data and CPT, fits the creep constitutive equation and obtained the material parameter. The numerical simulation is adopted to process age forming simulation on springback of T-specimen of aluminum 2124, and the simulation result is compared with the test result to do revision of the material parameter; the revised material parameter is applied into the numerical simulation of age forming of the integral panel which is of high strength. Through tests which can confirm the error ranges from -1mm to +1mm, this method’s accuracy is proved.

Testing CPT invariance with antiprotonic atoms

The structure of matter is related to symmetries on every level of study. The CPT symmetry is one of the most important laws of the field theory: it states the invariance of physical properties when one simultaneously changes the signs of the charge and of the spatial and time coordinates of particles. Although in general opinion CPT symmetry is not violated in Nature, there are theoretical attempts to develop CPT-violating models. The antiproton decelerator at CERN has been built to test CPT invariance. Its three experiments compare the properties of particles and antiparticles by studying antihydrogen, the positron–antiproton bound system and the antiprotonic helium atom.

Accounting for Soil Aging When Assessing Liquefaction Potential

It has been recognized that liquefaction resistance of sand increases with age due to processes such as cementation at particle contacts and increasing frictional resistance resulting from particle rearrangement and interlocking. As such, the currently available empirical correlations derived from liquefaction of young Holocene sand deposits, and used to determine liquefaction resistance of sand deposits from in situ soil indices standard penetration test SPT, cone penetration test CPT, shear wave velocity test Vs, are not applicable for old sand deposits. To overcome this limitation, a methodology was developed to account for the effect of aging on the liquefaction resistance of old sand deposits. The methodology is based upon the currently existing empirical boundary curves for Holocene age soils and utilizes correction factors presented in the literature that comprise the effect of aging on the in situ soil indices as well as on the field cyclic strength CRR. This paper describes how to combine currently recorded SPT, CPT, and Vs values with corresponding CRR values derived for aged soil deposits to generate new empirical boundary curves for aged soils. The method is illustrated using existing geotechnical data from four sites in the South Carolina Coastal Plain SCCP where sand boils associated with prehistoric earthquakes have been found. These sites involve sand deposits that are 200,000 to 450,000 years in age. This work shows that accounting for aging of soils in the SCCP yields less conservative results regarding the current liquefaction potential than when age is not considered. The modified boundary curves indicate that old sand deposits are more resistant to liquefaction than indicated by the existing empirical curves and can be used to evaluate the liquefaction potential at a specific site directly from the current in situ properties of the soil.

How accurately can one test CPT conservation with reactor and solar neutrino experiments?

We show that the combined data from solar neutrino experiments and from the KamLAND reactor neutrino experiment can establish an upper limit on, or detect, potential CPT violation in the neutrino sector of order 10−20 to 10−21 GeV.

Guanfacine Treatment of Cognitive Impairment in Schizophrenia

Norepinephrine plays a significant role in the working memory functions of the prefrontal cortex by its actions at alpha-2a noradrenergic receptors. Guanfacine has demonstrated efficacy in reversing working memory deficits in non-human primate. In the present study the effect of guanfacine adjunctive treatment to neuroleptics on the cognitive performance of schizophrenic patients was investigated in a four week, placebo-controlled, double-blind, parallel design trial. The primary analyses revealed no significant differences between guanfacine and placebo treatment; however, exploratory non-parametric statistics revealed some significant and some trend differences between guanfacine and placebo on spatial working memory test performance and CPT reaction time in those subjects treated with atypical neuroleptics.

CP and CPT physics with the KLOE experiment at DAΦNE

The KLOE experiment at the DAΦNE φ-factory of the Frascati Laboratories aims to measure the R( ε′ ε ) parameter of CP violation in K L decay to an absolute precision of ∼ 10 −4. By measuring the interference in K 0 K 0 decay times the experiment may also determine other relevant quantities as Δφ = φ +− − φ 00, Δm, τ L , τ S and test CPT conservation. The KLOE apparatus and its expected performances are described.