| The tensile stress caused by temperature change may exceed the concrete tensile strength during construction and operation of concrete dams, so cracks often appeare, the integrality and durability performances of the dams can be adversely affected. It is important to prevent harmful cracks for mass volume concrete dams.Rock-filled concrete (RFC) technology makes use of the high flow ability of self-compacting concrete (SCC), which can fill in the blanks of the rockfill body, forming concrete with performances of complete, continuous and high strength. Compared with normal concrete, RFC shares the advantages of lower adiabatic temperature rise, rapid construction and environmental protection. So far, RFC has been applied in many small hydraulic projects, however, many problems need to be studied, such as temperature control measures taken for RFC dams, which have not yet been published.According to literatures, RFC can be seen as homogeneous isotropic material. In this paper, using finite element analysis software SAPTIS(structure analysis program for temperature and induced stress) and taking a RFC dam to be built as an example, the temperature field and stress field are analyzed in the construction and operation by simulating material performance and construction process of the dam. And the temperature control measures and transverse joint arrangement are summarized for RFC dams.The results show:(1) compared with normal concrete in the same strength grade, the adiabatic temperature rise of RFC is smaller but the tensile strength is approximately equal, and the simplified temperature control measures can be taken. (2) pipe cooling and aggregate precooling measures cannot be taken for RFC dams, the maximum temperature locates in the internal dam body, and mainly relates to the concrete placing temperature, the environment temperature and the adiabatic temperature rise. (3) in cold season the concrete placing temperature is low and the maximum tensile stressis small, so that only conventional temperature control measures are taken such as surface cooling by flowing water and surface thermal insulation, and there is no need to part the dam body. (4) in high-temperature seasons the concrete placing temperature is high, simple temperature control measures such as surface cooling by flowing water and surface thermal insulation can make the maximum temperature and tensile stress drop to a certain extent, but if the range of temperature variation at the dam location is big, the dam with simple temperature control measures is still under high risk of cracks. (5) for concret placing in high-temperature seasons, dam body parting measures should be taken in order to prevent hamful craks, the joint arrangemeng is verified by simulating analysis of the dam. (6) in practical projects, according to the simulating analysys of the RFC dam, concrete can be placed quickly to the limit in cold seasons, and in high-temperature seasons, in addition to simple temperature control measures, concrete can be placed with wide-spacing joint arrangement in the dam. |
