Reddish weathered gravels are well found within Quaternary fluvial deposits in Japan. Such gravels are also generally softened. To understand the formation process of such gravels included within Quaternary fan deposits, both degree of color and softness of gravels, and their spatial distribution have been measured using some color and physical indices. As a result, the reddish grade which is one index of chemical weathering decreases as the penetrative strength of gravels degreases with the depth from the fan surface. Decrease of specific gravity and increase of porosity were also recognized in the same extents.
This means that change process in color may be closely related to physical/kinetic changes within gravels. However, compared with spatial distribution of reddish color in some places, the reddish distribution may also be strongly controlled by water table within the deposits.

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Complicated geometrical patterns of microcracks are caused by the change in stress field and the heterogeneity in rocks and so on. The geometrical patterns of microcracks are characterized by fractal dimensions, which are related to the physical constants, such as diffusion coefficient and permeability coefficient. The process for characterizing microcracks consists of extraction of microcracks, digitizing the extracted the patterns of microcracks and analysis of digitized data.
In this study, the geometrical patterns of microcracks in granitic rocks are characterized 8 bits (256 levels) gray scale data by using replica method and multifractal analysis which is an expansion of the fractal geometry. The result is summarized as follows:
1) The geometrical patterns of microcracks could be differentiated by width of microcrack.
2) The microcracks of granitic rocks are the multifractal set and have to be characterized by the generalized dimension D (q) which means spectra of the plural fractal dimensions.
3) The generalized dimension D (q) may be an index of a degree of the heterogeneity of the geometrical patterns of microcracks in granitic rocks.
The generalized dimension D (q), which is characterized by the distribution of patterns of microcracks in granitic rocks, could differentiate from its origin such as regional stress, sheeting and weathering.

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Permeability of an intact specimen and specimens subjected to slow, uniform temperature increase until 100 and 200°C in Inada granite was measured at the effective confining pressures up to 26MPa by transient pulse technique. In addition, permeability was predicted with various equivalent channel models by using the pore volume and pore volumetric distribution measured by the mercury intrusion porosimetry, and compared with the practically measured permeability. Main results are as follows.
Permeability of Inada granite increases with increase of heated peak temperature, and the permeability of specimen heated until 200°C is about 3.2 times as large as that of intact specimen. The reason for this is that microcracks were induced and extended by temperature increase. On the relationship between permeability and effective confining pressure, permeability decreases notably with the pressure increase until 16MPa, moreover, microcracks thermally induced closed almost at the range above 16MPa, and effects of high temperature an permeability disappeared almost.
Permeability predicted by the hydraulic radius model using porosity and pore volumetric distribution of specimens was in agreement with the practically measured permeability. Permeabilities predicted by capillary model, Marshall probabilistic model and Juang-Holtz probabilistic model diverged notably from the measured one, but the relationship between permeability and heated peak temperature was similar to that of measured permeability.

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The replica film method introduced by Suzuki and Takahashi (1994) is one of methods for observing microstructures in rocks, such as pores and cracks. In order to obtain the adequate image to extract microcracks on the replica film by image processing, we firstly propose a improved method for observing microcracks. The transmitted light is used in the ordinary method, while the reflected and refracted light is used in this proposed one.
Then the procedure and accuracy of image analysis is discussed to quantitatively evaluate the frequency distributions of crack orientation and length. The results show that the adaptive binarizarion method is suitable for extracting microcracks from these images. Further we point out that the action of line detection operators depend on the direction of cracks. Therefore these operators should be performed to the images from various directions. Based on these investigations, we make a procedure of image analysis for extracting microcracks. The frequency distributions of crack orientation, crack length and total crack length obtained from this procedure have similar tendency for that to be made by hand.

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