The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

Statistics and Data Analysis in Geology

Discrete particle simulation of particulate systems: A review of major applications and findings


 The spectral ratio between horizontal and vertical components (H/V ratio) of microtremors measured at the ground surface has been used to estimate fundamental periods and amplification factors of a site, although this technique lacks theoretical background. The aim of this article is to formulate the H/V technique in terms of the characteristics of Rayleigh and Love waves, and to contribute to improve the technique. The improvement includes use of not only peaks but also troughs in the H/V ratio for reliable estimation of the period and use of a newly proposed smoothing function for better estimation of the amplification factor. The formulation leads to a simple formula for the amplification factor expressed with the H/V ratio. With microtremor data measured at 546 junior high schools in 23 wards of Tokyo, the improved technique is applied to mapping site periods and amplification factors in the area.

Ground Motion Characteristics Estimated from Spectral Ratio between Horizontal and Verticcl Components of Mietremors.

A review of the recent advances on the treatment of industrial wastewaters by Sulfate Radical-based Advanced Oxidation Processes (SR-AOPs)

In this paper, reduced level of rock at Bangalore, India is arrived from the 652 boreholes data in the area covering 220 sq.km. In the context of prediction of reduced level of rock in the subsurface of Bangalore and to study the spatial variability of the rock depth, ordinary kriging and Support Vector Machine (SVM) models have been developed. In ordinary kriging, the knowledge of the semivariogram of the reduced level of rock from 652 points in Bangalore is used to predict the reduced level of rock at any point in the subsurface of Bangalore, where field measurements are not available. A cross validation (Q1 and Q2) analysis is also done for the developed ordinary kriging model. The SVM is a novel type of learning machine based on statistical learning theory, uses regression technique by introducing e-insensitive loss function has been used to predict the reduced level of rock from a large set of data. A comparison between ordinary kriging and SVM model demonstrates that the SVM is superior to ordinary kriging in predicting rock depth.

A comparative study of ordinary kriging and support vector machine models for the spatial variability of rock depth in Bangalore

Collapse of pile-supported structures is still observed in liquefiable soils after most major earthquakes and remains a continuing concern to the geotechnical engineering community. Current methods for pile design in liquefiable soils concentrate on a bending mechanism arising from lateral loads due to inertia and/or soil movement (kinematic loads). Recent investigations demonstrated that a pile or pile group can become laterally unstable (buckling instability/ bifurcation) under the axial load (due to the dead load) alone if the soil surrounding the pile liquefies in an earthquake. This is due to the liquefaction-induced elimination of the soil bracings and the governing mechanism is similar to Eulerâ€™s buckling of unsupported struts. Analysed are 26 cases of pile foundation performance in liquefiable soils giving emphasis to the buckling instability using Support Vector Machine (SVM) method. SVM has recently emerged as an elegant pattern recognition tool. This tool has been used to classify pile performance against buckling failure. Each of the case studies reported is represented by four parameters: Effective buckling length of pile (Leff), the allowable load on the pile (P), Eulerâ€™s elastic critical load of the pile (Pcr) and minimum radius of gyration of the pile (rmin). The performance of the developed SVM is 100%.

Support Vector Classifiers for Prediction of Pile Foundation Performance in Liquefied Ground During Earthquakes

In view of the major advancement made in understanding the seismicity and seismotectonics of this region in recent times, an updated probabilistic seismic hazard map of India covering 6°–38° N and 68°–98° E was prepared and presented in this paper. In present analysis, three types of seismic sources, viz. linear, areal and zoneless models were considered and different attenuation relations were used for different tectonic provinces. The study area was divided into small grids of size 0.1° x 0.1° and the PHA and Sa values were evaluated at the centre of each grid point. A MATLAB code has been developed to estimate the hazard using linear sources and zoneless approach whereas CRISIS software was used to model areal sources. Comparison of different methodologies is presented in the paper. The linear source model predicts higher hazard compared to other two source models and Zoneless approach gives the lower value of hazard at a particular grid point. For most of the cities, gridded seismicity model is giving higher values compared to aerial sources except for Ahmedabad, Chennai, and Kanpur.

Probabilistic Evaluation of Seismic Hazard in India: Comparison of Different Methodologies

/pdf/dem-modelling-of-granular-materials-during-cyclic-loading-4qfdena3i5.pdf

Dem Modelling of Granular Materials During Cyclic Loading

Problem statement: The conventional liquefaction evaluation is based on a deterministic approach. However in this method the uncertainty in the earthquake loading is not properly taken into account. However recent research in this field indi cates that this uncertainty in the earthquake loadi ng has to be considered in the liquefaction potential evaluation. Moreover the evaluation of liquefaction return period is not possible in the conventional d eterministic methods. This study explained the methods for evaluating the probability of liquefact ion and the return period of liquefaction based on probabilistic approach. Approach: In this study the geotechnical data was collected from 450 bore holes in Bangalore, India, covering an area of 220 km 2 . The seismic hazard analysis for the study area is carried out using Probabilistic Seismic Hazard A nalysis (PSHA) and the peak acceleration at ground surface was evaluated for site class-D after considering local site effects. For assessment of site class, shear wave velocity profiles in the cit y had been obtained using Multichannel Analysis of Surface Waves (MASW) survey. Based on this data the probabilistic liquefaction analysis was done to evaluate the probability of liquefaction in the study area. Based on the performance based approach the liquefaction return period for the study area w as also evaluated. Results: The results showed the variation of liquefaction susceptibility for the st udy area. The corrected standard penetration values required to prevent the liquefaction for return per iods of 475 and 2500 years were also presented here . Conclusion/Recommendations: The spatial variation of probability of liquefacti on and the factor of safety against liquefaction evaluated using the two methods match well for the study area.

T. G. Sitharam

Papers

A comparative study of ordinary kriging and support vector machine models for the spatial variability of rock depth in Bangalore

Support Vector Classifiers for Prediction of Pile Foundation Performance in Liquefied Ground During Earthquakes

Probabilistic Evaluation of Seismic Hazard in India: Comparison of Different Methodologies

Dem Modelling of Granular Materials During Cyclic Loading

Evaluation of Liquefaction Return Period for Bangalore Based on Standard Penetration Test Data: Performance Based Approach