虚拟热源法研究坝基裂隙岩体渗漏通道

DETECTION OF LEAKAGE PASSAGE IN FISSURE ROCK WITH ASSUMPTIVE HEAT SOURCE METHOD

利用虚拟热源法研究坝基裂隙岩体中存在的集中渗漏通道。水库底部通常为低温水,而基岩温度随着深度的增加而升高,坝后温度异常区域可能存在库水渗漏。渗漏水与周围地层将进行热量的交换。低温的渗漏水从地层中吸收热量,而地层则释放出热量,根据能量守恒原理,这两个热量是相等的。将集中渗漏通道看作是一个虚拟线热源,通道以外地层温度的分布仅与渗漏带最外层的温度有关,与渗漏通道内部的温度分布无关,渗漏通道内部的温度是由水流带来的,其外部的温度是靠热传导进行。根据热传导及能量守恒理论,可以推导出温度在地层中的分布趋势,通过温度分布曲线可以确定渗漏范围,建立堤坝渗漏量的虚拟热源法模型;同时,对具体工程实例进行了定量计算。

The concentrated leakage passage in fissured rock is studied with dummy heat source method. The temperature of reservoir water at the bottom is commonly low, whereas the temperature of bedrock increases with depth, so there will be reservoir water leakage around the temperature abnormal area at the dam site. There will be thermal exchange between the leakage and around strata. The leakage water with low temperature will absorb heat from strata; and on the other hand, the strata will discharge heat. According to the theory of energy conservation, these qualities of heat mentioned above are equal. The concentrated leakage passage can be regarded as a dummy heat source; moreover, the temperature distribution in stratum out of the passage is only influenced by the surface layer of passage and not relative to the inner temperature distribution of the passage, namely, the inner temperature distribution of passage is caused by water and the outside temperature distribution is shaped by heat conduction. Then, based on the theory of heat conduction and energy conservation, the temperature distribution in strata can be determined, which can be used to locate the leakage area. A dummy heat source model is proposed to calculate the quantity of leakage water. As an example, a reservoir leakage is analyzed quantitatively.