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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)

This paper presents the seismic site characterization carried out for Karnataka (state level) as well as for India (country level) using topographic slope map derived from Digital Elevation Model (DEM) data. Two DEM data, SRTM, and ASTER were used to derive the slope maps. For Karnataka (state level), the slope map was generated from ASTER DEM considering a grid size of 5 × 5 km and for India (country level), the slope map was generated from SRTM DEM considering the grid size of 10 × 10 km. Based on the slope value, every grid point was characterized into various NEHRP site classes, and spatial variation of average shear wave velocity for top 30 m (Vs30) value throughout the study areas is presented in this paper. Peak horizontal acceleration (PHA) at bedrock level was evaluated for the same grid points using deterministic as well as probabilistic methodologies. The amplification factor for every grid point was obtained from the site coefficients corresponding to NEHRP site class. The surface level peak horizontal acceleration (PHA) was then evaluated for every grid point by multiplying bedrock level PHA with the corresponding amplification factor. Spatial variation of seismic hazard at the surface for the state of Karnataka as well as for entire India is presented in this paper.

Site Characterization Using Satellite Data and Estimation of Seismic Hazard at Ground Surface

This chapter presents the results of the laboratory model tests and the numerical studies conducted on small diameter PVC pipes, buried in geocell reinforced sand beds. The aim of the study was to evaluate the suitability of the geocell reinforcement in protecting the underground utilities and buried pipelines. In addition to geocells, the efficacy of only geogrid and geocell with additional basal geogrid cases was also studied. A PVC (Poly Vinyl Chloride) pipe with external diameter 75 mm and thickness 1.4 mm was used in the experiments. The vehicle tire contact pressure was simulated by applying the pressure on the top of the bed with the help of a steel plate. Results suggest that the use of geocells with additional basal geogrid considerably reduces the deformation of the pipe as compared to other types of reinforcements. Further, the depth of placement of pipe was also varied between 1B and 2B (B is the width of loading plate) below the plate in the presence of geocell with additional basal geogrid. More than 50% reduction in the pressure and more than 40% reduction in the strain values were observed in the presence of reinforcements at different depths as compared to the unreinforced beds. Conversely, the performance of the subgrade soil was also found to be marginally influenced by the position of the pipe, even in the presence of the relatively stiff reinforcement system. Further, experimental results were validated with three-dimensional numerical studies using FLAC3D (Fast Lagrangian Analysis of Continua in 3D). A good agreement in the measured pipe stain values was observed between the experimental and numerical studies. Numerical studies revealed that the geocells distribute the stresses in the lateral direction and thus reduce the pressure on the pipe. In addition, the results of the 1-g model tests were scaled up to the prototype case of the shallow buried pipeline below the pavement using the appropriate scaling laws.

Protection of Buried Pipelines and Underground Utilities Using Geocells

The uniqueness of this paper is large amount of field test data and in addition laboratory test results on undisturbed soil samples, has been analyzed to capture the effect of local site condition and material properties of overlying soil on seismic ground motion characteristics This study involves the seismic site characterization and ground response analysis of an offshore site in Western Yemen From the results of field and laboratory tests, dynamic properties such as shear modulus and damping ratio for a very low to high strain levels was determined and site characterization was also carried out Using seismic cone penetration test (SCPT) data a new correlation has been developed to predict the shear wave velocity Synthetic ground motion was generated using Boore's stochastic modeling technique for ground response analysis and peak ground acceleration (PGA) was evaluated and presented in the paper This paper also presents a site specific design response spectrum based on Eurocode, corresponding to 475 and 2500 year return period

Dynamic Characterization and Site Response Studies for an Offshore Site Based on Detailed Geotechnical Tests

Wedge Failure Analysis of Slopes in Highly Jointed Rock Masses in the Zones of High Seismicity

Liquefaction is a devastating effect of earthquakes resulting in sudden decrease in shear strength due to excess pore water pressure generation, resulting in differential settlement of structure, inducing severe damages. Assessment of liquefaction hazard for a given site is important for planning out mitigation works. In this paper the liquefaction susceptibility using deterministic and probabilistic methodologies was assessed and results are presented in terms of liquefaction potential index (LPI) for a nuclear power plant site. The results of this study are explored further in the article.

T. G. Sitharam

Papers

Site Characterization Using Satellite Data and Estimation of Seismic Hazard at Ground Surface

Protection of Buried Pipelines and Underground Utilities Using Geocells

Dynamic Characterization and Site Response Studies for an Offshore Site Based on Detailed Geotechnical Tests

Wedge Failure Analysis of Slopes in Highly Jointed Rock Masses in the Zones of High Seismicity

Assessment of Liquefaction Potential Index Using Deterministic and Probabilistic Approaches