ABSTRACT
Mianhuatan RCC dam of 111.0 m height, 84.50 m bed width and 308.50 m crest length is located in Fujian province of China. Its 5# monolith has a width of 64.0 m, in which a bottom outlet is placed, and is constructed on a complicated foundation. The construction of this monolith began on Feb, 1999 and completed at the end of 2000. During the placing of concrete, some cracks occurred near foundation. To prevent new cracks in newly placed concrete, two induced joints were set. In order to have the knowledge of the status of temperature and stress, this paper numerically simulates the variation and distribution of temperature and stress under real construction condition. The result shows that: 1) The temperature rise caused by hydration was about 12–16°C for RCC and 20–25°C for normal concrete, and peak value appeared between 1–2 months after the placement. 2) The maximum tensile stress near the dam surface reached 3–5 MPa in winter, while at middle part of the dam it was up to 2–2.5 MPa after the whole dam was cooled. The tensile stress of high value occurred in concrete placed at high temperature season. 3) Large tensile stress appeared at the up and downstream surface of the dam in cool season, leading to possible cracks there. 4) Because of the larger tensile stress inside the dam, cracks on the surface may propagate into or finally through the dam. 5) The tensile stress is not large enough to make the induced crack propagate above the elevation of 148.0 m. 6) Appropriate width for RCC gravity dam is around 20–30 m.
