Study on the estimation method of the mechanical characteristics and internal stresses of existing dam concrete

第二次世界大战后，为了满足日益增长的电力能源需求，日本建造了许多用于水力发电的混凝土水坝。这些大坝建成至今已有40多年。为了对大坝进行适当的维护，有必要建立一种基于大坝现状的安全评价方法。也就是说，为了验证既有大坝的长期安全性，必须准确地评估构成大坝的混凝土的力学性能，并对大坝混凝土内应力的预测方法进行升级。在此基础上，提出了基于复合理论的由水泥浆体和骨料的杨氏模量估算大坝混凝土杨氏模量的方法。此外，通过对重力型大坝的模拟，阐明了考虑自收缩时，表面混凝土开裂的概率增大。

Many concrete dams were constructed for hydroelectric power generation in Japan to meet the growing electric power energy demand after World War II. More than 40 years have passed already since the construction of these dams. For their appropriate maintenance, it is necessary to establish a safety evaluation method for dams based on their present conditions. That is, to verify the long-term safety of an existing dam, the mechanical properties of concrete that composes the dam must be accurately evaluated and the upgrade of the prediction methd of an internal stress of the dam concrete is also necessary. As a result, it was proposed the method to estimate a Young's modulus of dam concrete from the Yonug's modulus of the cement paste and the aggregate based on the composite theory. In addition, as a result of simulation of the gravity-type dam it was clarified that the probability of cracking of surface concrete increased when self-shrinkage was considered.