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a b s t r a c tSoil liquefaction is a major cause of seismic damage in cohessionless soil during earthquakes. From past numerical and experimental research it has been observed that more excess pore water pressure (EPWP) is generated during earthquakes in a heterogeneous soil deposit than in the corresponding homogeneous soil with relative density equal to the average relative density of the heterogeneous soil. This interesting phenomenon is investigated here, by numerically simulating centrifuge experiments of seismically induced soil liquefaction using the finite element code DYNAFLOW. Two centrifuge tests are numerically simulated here: one in homogeneous soil and another in heterogeneous soil. Recorded experimental results such as accelerations, EPWP and settlements are compared with the simulated numerical results. Numerically simulated and recorded results support the conclusions of previous research that more EPWP is generated in a heterogeneous soil deposits than in the corresponding homogeneous soil.

One of the three basic needs for mankind's survival is shelter which is not adequate in India as per the estimation reported by the Ministry of Housing and Urban Poverty Alleviation, Government of India. With an annual population growth rate of 1.64 % as compared to world population growth rate of 1.23 % during the last decade there is a great vulnerability to housing needs in the coming decades. This would result in an enormous over dependence on traditional building materials like steel, cement and wood. To reduce this over dependence there is a need to review alternate building materials and formulate guidelines for their application in construction industry. This paper focuses on the recent advancements in energy efficient, eco-friendly low cost building materials like fly ash, earthen materials and natural fibers (bamboo) along with the different problems associated with them. Numerous technologies are available nowadays to build two storey bamboo house, pre-engineered bamboo portal frame buildings, composite bamboo beams and columns, fly ash concrete, fly ash bricks, fly ash blocks, non-erodible mud plaster, terra cotta skin in mud walls, tumbler tiles, and fibrous boards. The recent developments in this area in India by various organizations like Building Materials and Technology Promotion Council (BMTPC), Central Building Research Institute (CBRI), Indian Institute of Technology (Delhi, Roorkee, Madras, Kharagpur) and Indian Plywood Industries Research and Training Institute (IPIRTI) have been discussed along with their potential applications, cost aspects. Numerous problems such as lack of codal guidelines, technology transfer and manufacturing facilities associated with these materials have been discussed. Need of the hour is for their widespread usage and awareness among peoples but the lack of specific guidelines unlike other countries hinder their application.

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