著者

中村 康夫

出版者

一般社団法人日本応用地質学会

雑誌

応用地質 (ISSN:02867737)

巻号頁・発行日

vol.20, no.4, pp.140-149, 1979-12-30

被引用文献数

3 3

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The prevision or estimation of rock durability is a very important and complex problem in engineering geology and civil engineering. Especially the durability of rocks for use as riprap of fill dams has a close relationship to their safety. the author has been studying on the durability of various rock s for use as riprap of fill dams by means of laboratory freezing and thawing test. As the first step, obtained results are as follows. (1) The deterioration characteristics of rocks are classified into following three types. A: No deterioration occurs in matrix itself. Sudden break to two or more pieces occurs along cracks after repeating certain freezing and thawing cycles. B: Progressive deterioration occurs in matrix itself. Exfoliation from the surface of test pieces occurs at any freezing and thawing cycles. C: Intermediate type between A and B. Type A rocks seem to be durable and no problem will occur for using as riprap of fill dams unless break will occur within the setting cycles. Durability of type and C rock can be estimated by the value of weight loss at the setting cycles. (2) Under freezing and thawing test, changes of saturation moisture content, effective porosity, dry density, coefficient of dynamic elasticity and shore hardness have a close relationship to the deterioration characteristics of rocks and can be classified into several patterns. (3) Freezing and thawing should be repeated at least 100 cycles to estimate rock durability. if it continues extra 100 cycle (i.e. 200 cycles), more precise estimation can be done on many deterioration characteristics of rocks, for example, the rate of deterioration. The rocks that weight loss occur less than 10% at 200 cycles are very durable and seem to cause no problem using for riprap of fill dams. (4) The durability of rocks can be estimated to some degree from initial values of the physico-mechanical properties. bu such method is very rough and sometimes even unreliable. In order to estimate the durability of rocks more precisely, it is necessary to make direct accelerated deterioration experiments such as freezing and thawing test and measure various changes of physical properties.