碾压混凝土拱坝的封拱温度与真实温度荷载研究

本文在对RCC混凝土拱坝封拱温度与温度荷载特点分析的基础上，用四座不同坝高的RCC拱坝分别以坝体多年平均温度和由仿真分析计算得到的蓄水时的实际温度作为温度荷载的计算起点，用有限元等效应力法计算不同坝高的坝体应力，根据计算结果讨论不同坝高时RCC大坝的封拱温度与温度荷载。本文主要得出以下结论：1）以多年平均温度作为封拱温度计算温度荷载与仿真方法计算的温度荷载的差距随着坝高的增大而增大。对于100米以上的拱坝应该用仿真分析的方法研究温度荷载，以确定真实的封拱温度。2）不进行二期水冷和封拱灌浆时，对于100m以上的高拱坝，要进行充分论证，一般坝踵可能会出现较大拉应力而引起坝踵开裂。3）对于RCC高拱坝应采用冷却水管和分缝相结合的方式，在蓄水前通过二期水冷使坝体温度下降到设计封拱温度后进行封拱灌浆，以减小运行期的温度荷载。

Grouting Temperature and Thermal Load of RCC Arch Dam

Based on the analysis of arch sealing temperature and temperature load of RCC arch dam, taken perennial average temperature of the dam and the practical temperature during impounding which is calculated from simulating analysis as the starting point of calculation for four RCC arch dams with different heights, dam stresses in different heights are calculated by finite element equivalent stress method. The arch sealing temperature and temperature load of the RCC dam in different heights are discussed according to the calculating results. The following conclusions are obtained: 1) The difference between temperature load calculated by taken perennial average temperature as the arch sealing temperature and temperature load calculated by simulating method will increase with the increase of dam height. For arch dams which are more than 100m high, simulating analysis method should be used to study the temperature load to determine the real arch sealing temperature. 2) If second phase water cooling and arch sealing and grouting are not carried out, adequate argumentation should be conducted. Generally, large tensile stress will appear on the dam heel, which will induce cracking of the dam heel. 3) Water cooling pipe and jointing mode should be adopted to RCC high arch dam. To reduce the temperature load in operation, use second phase water cooling to lower the dam temperature to designed arch sealing temperature before impounding, and then conduct arch sealing and grouting.