Study On Method Of Temperature And Moisture Controlling For Crack Preventing Of Hydraulic Concrete

In this dissertation, several topics including the simulative model and the theoretics of temperature field and stress field in concrete, the macro-mesco theory and numerical method of moisture field and drying shrinkage stress, the calculation method of cooling pipe, and feedback analysis of thermal characteristic parameters, which all have correlation with practical engineering, are studied. The main contents of this dissertation are as follows:(1) The development and present research state of the concrete temperature controlling and simulative calculation, moisture field and drying shrinkage stress, and the mescopical damage mechanics have been reviewed and expatiated. Some problems still remained and needed to be solved in these fields were pointed out, and some advanced practical way and research thought for solved the aforementioned problem are suggested.(2) The un-stability calculation theory of concrete temperature field and stress field in which the influence of temperature itself and the time have been considered was introduced, the characteristic of temperature varied with the time and itself temperature was added to the hydration model of cement, and the influence of materials damage also has been taken into account in simulation of temperature and structure calculation of massive concrete.(3) The calculation of cooling pipe was realized when the inner boundary of pipe was considered as the first-kind and the third-kind separately, the "equivalent surface coefficient" of pipe in Zhougongzai arch dam when the boundary of cooling pipe was considered as the third-kind. The relation between the "equivalent surface coefficient" and the water of flux in pipe was understand. The different cooling effect between PE pipe and iron pipe are compared, and some useful conclusion and suggestion could be used in practical engineering were obtain.(4) The simulative calculation of the 3-D non-linearity un-stability moisture field and the drying shrinkage stress field in the macro and micro level was carried out. It think that autogenous shrinkage should not omitted from the simulation of moisture for HPC. In the mescopical level, a random mescopical multilaminate composite model of concrete was build, the difference of diffusion mechanism between the macroscopical and mescopical moisture field was discussed and the mescopical law of the drying distortion and its stress was studied when the materials characteristic of different phases were considered. Moreover, the calculation of drying shrinkage distortion and its stress built on moisture diffusion theory should consider the influence of the damage. In the last, coupling calculation of the moisture, drying shrinkage distortion and its stress has been realized in the mescopical level.(5) The Improved accelerating genetic algorithm was used to solved the feedback problem of multi-parameter. One new model "multi-exponential+hyperbola" was put forward to draw up the hydration progress of concrete, results from several tests in laboratory and in-situ have showed that the calculation value made a good agree with the measurement value. It is successful to carry out the simulative calculation and result predicting of the going project by using the parameter get from the project have already been ended.(6) With the help of an improved strict numerical algorithm of 3D-non-linearity un-stability temperature and stress field including pipe cooling, simulative analysis of the effect of cooling pipe in two typical (7# and 12#)in Zhougongzai arch dam ,has been put on, "varied temperature scheme" was suggested to meet the need for temperature controlling and crack protecting in different seasons, a suit of effective scheme for the two typical segment in arch dam was...