Estimation of Durability and Deterioration Characteristics of Rocks by Laboratory Freezing and Thawing Test
Estimation of Durability and Deterioration Characteristics of Rocks by Laboratory Freezing and Thawing Test
复制标题
通过实验室冻融试验评价岩石的耐久性和劣化特征
DOI：
10.5110/jjseg.20.140
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
Yasuo Nakamura
中科院分区：
文献类型：
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作者：
Yasuo Nakamura
岩石耐久性的预测和评价是工程地质学和土木工程中一个非常重要和复杂的问题。尤其是堆石坝抛石用岩石的耐久性与其安全性密切相关。通过室内冻融试验，对各种堆石料的耐久性进行了研究。作为第一步，得到的结果如下：(1)岩石的变质特征可分为以下三种类型：A：基质本身不发生变质。在重复一定的冻结和解冻循环后，沿着裂缝突然断裂成两个或两个以上的碎片。B：基质本身发生进行性恶化。在任何冻融循环中，试件表面都会发生剥落。C：介于A和B之间的中间类型。A类岩石似乎是耐用的，用作堆石坝的抛石不会出现问题，除非在凝结周期内发生破裂。在冻融试验条件下，饱和含水率、有效孔隙率、干密度、动弹性系数和岸边硬度的变化与岩石的劣化特性密切相关，并可分为几种模式。(3)冻融试验至少要重复100次才能评价岩石的耐久性。如果再继续100个循环(即200个循环)，则可以对岩石的许多退化特征进行更精确的估计，例如退化速率。200次循环失重小于10%的岩石非常耐久，用于堆石坝抛石似乎不成问题。(4)从岩石物理力学性质的初值可以在一定程度上估计岩石的耐久性。但这种方法非常粗暴，有时甚至不可靠。为了更准确地估计岩石的耐久性，有必要进行冻融试验等直接加速劣化试验，并测量各种物理性质的变化。
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 rocks 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 B and C rocks 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 cycles (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 value of the physico-mechanical properties. But 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.