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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)

Desaturation of in-situ saturated sandy soils is emerging as a new cost effective and environment friendly liquefaction mitigation technique. In the present study, stress controlled undrained cyclic triaxial tests have been conducted on air injected-desaturated sandy soil and various important issues such as number of cycles required for initial liquefaction, cyclic strength of desaturated sand, modes of failure, evolution of pore pressure, have been explored in detail. Number of cycles required for initial liquefaction increased exponentially with decrease in degree of saturation. Cyclic strength of desaturated sand with degree of saturation of 80% is found to be twice that of saturated sand, for relative density of 40%. Assessment of performance of desaturated sand under various earthquake records revealed that desaturated sand with degree of saturation of 70% can prevent liquefaction during moderate to strong earthquakes having peak ground acceleration as high as 0.30 g. Further, sample with high degree of saturation underwent cyclic mobility failure. In samples with low degree of saturation, two types of cyclic softening failures demarcated by two distinct phase transformation trends were observed. A pore pressure model proposed by Konstadinoun and Georgiannou (2014) has been modified to predict the pore pressure evolution in desaturated sand.

Liquefaction Resistance and Cyclic Response of Air Injected-Desaturated Sandy Soil

Probabilistic seismic hazard macrozonation of India

Evidences from past earthquakes clearly show that the damages due to an earthquake and its severity at a site are controlled mainly by three factors, i.e., earthquake source and path characteristics, local geological and geotechnical characteristics, and structural design and quality of the construction. Seismic ground response at a site is strongly influenced by local geological and geotechnical conditions. The exact information of the geological, geomorphological, and geotechnical data along with seismotectonic details at a particular site are necessary to evaluate the ground response. The geometry of the subsoil structure, the soil type, the lateral discontinuities, and the surface topography will also influence the site response at a particular location. Since the seismic effects on the structure depend fully on the site conditions, research in the area of soil dynamics becomes more useful. The first input required in evaluation of geotechnical aspect of seismic hazard is the rock-level peak horizontal acceleration (PHA) values. The surface-level acceleration values need to be calculated based on the site conditions and site amplification values. This chapter discusses the recent advances in soil dynamics, especially in the area of geotechnical earthquake engineering. The topics covered in this chapter include various methods for evaluating the local site effects, dynamic soil properties, different field and laboratory tests required, various site classification schemes, and different methods to evaluate the surface-level ground motion. In addition to this, the aspects which need to be considered in liquefaction potential evaluation are also discussed.

Recent Advances in Soil Dynamics Relevant to Geotechnical Earthquake Engineering

This paper presents, unit weight, shear wave velocity, strain-dependent normalized shear modulus reduction and material damping ratio relationships for Mavallipura landfill are developed based on field testing, laboratory measurements and also validated using semi-empirical methods. In addition, one-dimensional seismic response analysis by an equivalent linear method for Mavallipura landfill, Bangalore using the software like SHAKE2000 and DEEPSOIL. Results indicated that the MSW landfill has less shear stiffness and more amplification due to the loose filling and damping, which need to be accounted for seismically safe MSW landfill design in India.

T. G. Sitharam

Papers

Liquefaction Resistance and Cyclic Response of Air Injected-Desaturated Sandy Soil

Probabilistic seismic hazard macrozonation of India

Recent Advances in Soil Dynamics Relevant to Geotechnical Earthquake Engineering

Seismic Analysis of Municipal Solid Waste Landfill in India

Evaluation of dynamic properties of municipal solid waste sites by geophysical tests