Proceedings of the 14th international conference of international association for computer methods and recent advances in geomechanics, Kyoto, Japan, 22–25 september 2014

Over the last half a century, constitutive models for geomaterials and numerical analysis methods have been well developed. Nowadays, numerical methods play a very important role in Geotechnical Engineering. The first pioneering conference was held at Waterways Experiment Station, Vicksburg, Mississippi, USA in 1972 under the leadership of Prof. C.S. Desai. Then, subsequent conferences were held in Blacksburg (USA) – 1976, Aachen (Germany) – 1979, Edmonton (Canada) – 1982, Nagoya (Japan) – 1985, Innsbruck (Austria) – 1988, Cairns (Australia) – 1991, Morgantown (USA) – 1994, Wuhan (China) – 1997, Tucson (USA) – 2001, Torino (Italy) – 2005, and Goa (India) – 2008. Now the conference is organized by IACMAG every three years. The last one, the 13th International Conference on Computer Methods and Advances in Geomechanics, was held in Melbourne, Australia in 2011. The 14th conference, here in Kyoto, was accepted at the Melbourne conference in 2011. This conference series is the main activity of the International Association for Computer Methods and Advances in Geomechanics founded in 70’s by Prof. C.S. Desai of the University of Arizona; the present president of IACMAG is Prof. J. Carter of the University of Newcastle. <...>

Conventionally, geochemical exploration for gold is based on the assumptions that (1) gold is chemically inert in surficial environments; (2) gold occurs mainly in discrete grains; and (3) gold is transferred by mechanical means to form clastic dispersion halos and dispersion trains. Consequently, the commonly adopted methodology has been (1) to determine gold in heavy mineral concentrates; (2) to use large samples in order to improve the reproducibility of gold analyses; (3) to use high detection limits and thresholds; and (4) to determine total gold contents and pathfinder elements in the samples. However, these methods are not always successful in locating gold deposits, and they have limited application in the search for buried or blind deposits.

In China, studies of the distribution and migration of particulate and ultrafine gold indicated that (1) gold is active and mobile in surficial environments; (2) gold occurs not only as discrete grains, but also as ultrafine particles and other complex forms; and (3) regional low-concentration gold anomalies as well as local anomalies over buried gold deposits originate from ultrafine gold and other complex forms of gold. The methodology developed in China for regional and local geochemical gold exploration is based on this experience. Results of investigations around two gold deposits in China are presented.

Petrography (from the Greek petra meaning rock and graphus meaning writing or a record) originated over 150 years ago as a technique employed primarily by geologists, who used microscopes to examine rock samples to identify their mineralogical and chemical characteristics. Petrographic techniques have since been applied to a wide range of materials used in construction including building stone, aggregate, soil, cement, concrete, mortar, brick, and bituminous mixtures. The polarising microscope has been used for the examination of cementitious materials since 1887. Almost one hundred years ago a series of six articles'1' in Concrete and Concrete Construction, the forerunner of today's CONCRETE, described the possibilities of using a microscope for examining concrete. In the last 40 years, petrography has become widely used for both research and commercial investigation of concrete structures. Petrographic examination is a laboratory procedure that is unique in that it relies highly on visual inspection of the samples. It requires specialist sample preparation and microscopical equipment and operators with appropriate qualifications and experience. Using the microscope the petrographer can determine the composition of concrete, assess its quality, and investigate the causes and extent of any deterioration. Photographs taken through the microscope (photomicrographs) record petrographic features of concrete samples. <...>

Detailed spatial models generated by conditional simulation provide a powerful tool for case-specific optimization of sampling designs. The entire process of sampling, estimation, and decision can be simulated on such a model by a Monte-Carlo approach. Optimization can be based on economic functions or on decision quality constraints rather than simple minimization of estimation variance.