Tham khảo tài liệu 'earth sciences part 2', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 30 Earth Sciences Quantitative Weathering Index Ia can be formulated following formula Ceryan et al 2008b la 100 - 100 - Iad Id 20 Advantageous of the numerical weathering index proposed by Ceryan et al 2008b were given as follows - During the P-wave velocity tests the samples are not disturbed and hence the test can produce many results using one sample. - Descriptions of mineralogical and physical changes seperately allow to make a comparison between two. By using this comparison it is possible to assess the weathering process. - It is possible to construct some correlations between the numerical weathering index and the engineering properties of rocks. By using these correlations the engineering properties of the weathered rock material can be predicted easily and reliably. - It is possible to classify the weathering degrees of igneous rocks by using the numerical weathering index and the weathering classes provide important informations about engineering behaviour of igneous rocks. - When determining the weathering degress of pyroclastic rocks such as tuff by using the numerical weathering index the homogeneity of the rock to be employed should be checked because the P-wave velocity shows a high variety depending on heterogeneity. - It is evident that if the pre-existing voids and or the voids created by weathering are oriented Vp and mechanical properties also change depending on measurement orientation. To cope with this difficulty the minimum Vp value can be used as stated by Weiss et al. 2002 . - The numerical weathering index should not be applied on the rocks showing the soluble type weathering. 4. A case study Weathering and weatherability of Harsit granitic rock Weathering of Harsit granitic rock In the study area the basement rocks are basalts andesites and pyroclastic units Figure 5 . The Harsit granitoid was intruded in the Upper Cretaceous Eocene period Towards the periphery of the pluton it consists of lucocratic quartz diorite quartz .
