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选取中国高放射核废物地下处置库重要预选场区——甘肃北山地区的花岗岩,加工组合成规则裂隙岩体,将垂直裂隙用粒径为0.5～0.63 mm的砂土填充,进行了裂隙水渗流传热试验;对模型试验进行了数值模拟,进而计算分析了热源温度、裂隙水流速和裂隙开度变化对裂隙岩体模型稳态温度场的影响。模型试验表明,当热源温度维持在120℃时,裂隙水仍无相变,裂隙岩体模型稳态温度场分布规律与热源温度为95℃时一致;热源温度越高,热源的水平影响距离越大,模型达到稳态需要的时间越长;裂隙填砂加强了裂隙两侧岩石之间的热传导,热源的水平影响距离和模型到达稳态需要的时间均明显大于无填充裂隙岩体模型的情况。模型试验得到的岩体模型温度场与数值计算得到的岩体模型温度场规律一致。试验过程中裂隙岩体模型在边界上存在一些热量散失,无法与数值计算中的绝热边界条件等同,致使试验数据低于数值计算值,并且热源温度越高,两者之间的差异越大。模型试验和数值计算均表明,邻近热源侧的裂隙水渗流对模型的温度场分布起控制作用,而远离热源侧的裂隙水渗流则主要影响该侧的边界温度和模型达到稳态所需要的时间。数值参数敏感性分析表明,裂隙水流速与裂隙开度越大,裂隙水对水平传热的阻滞作用越明显。
The granitic rocks in Beishan area, Gansu, an important preselected field in the underground repository of high-level radioactive nuclear waste in China, were selected and processed into regular fractured rock mass. The vertical fractures were filled with sand with particle size of 0.5-0.63 mm and fractured water seepage Heat transfer test was carried out. The model test was carried out by numerical simulation. Then the effect of heat source temperature, fissure water flow rate and crack opening on the steady-state temperature field of fractured rock mass model was calculated and analyzed. The model tests show that when the heat source temperature is maintained at 120 ℃, there is still no phase change in the fissure water, and the steady-state temperature distribution of the fractured rock mass model is consistent with that when the heat source temperature is 95 ℃. The higher the heat source temperature, The longer the time required for the model to reach steady state, the fissure sand filling enhances the heat conduction between the rocks on both sides of the fissure, and the time required for the horizontal distance and the time required for the heat source to reach the steady state are significantly larger than those for the unfilled fractured rock mass model . The temperature field of the rock mass model obtained from the model experiment is consistent with the temperature field of the rock mass model obtained by numerical calculation. During the experiment, the fractured rock mass model has some heat loss at the boundary and can not be equal to the adiabatic boundary conditions in the numerical calculation. As a result, the experimental data is lower than the numerical calculation value, and the higher the heat source temperature, the greater the difference between the two. Both model tests and numerical calculations show that the fractured seepage flow near the heat source plays a controlling role in the temperature field distribution of the model while the fissure water seepage away from the heat source side mainly affects the boundary temperature and the time required for the model to reach steady state . The numerical parameter sensitivity analysis shows that the larger the fissure water flow rate and fracture opening, the more obvious the effect of fissure water on horizontal heat transfer.