锅盖效应的水汽循环规律研究

Research on the law of water vapor circulation of the pot cover effect

在已有的锅盖效应研究的基础上,针对实际工程中由上至下具有覆盖层(相当于"锅盖")、碎石层、黏土层结构的路面和跑道等,研究锅盖效应导致的增水规律。通过开展室内试验,模拟实际工程中的道基结构,在开放和封闭两种条件下,分别分析土层增水规律。试验结果表明:两种试验条件下存在锅盖效应水汽循环现象,两者的水头循环峰值不同。对水头进行计算,解释了两种试验条件下产生水汽循环的内在机制。对封闭系统的循环水量进行计算,验证了两组试验在半个循环内产生的循环水量大致相等。锅盖效应导致的增水规律与碎石层下部是否平坦有关。若碎石层下部不平坦,碎石层里的水会不断累积;若碎石层下部平坦,当碎石层里的水增加到一定量后,水量不会再增加,定量的水在碎石层里进行水汽循环。工程中应该设计有利的道基结构防止道面下大量增水。

On the basis of the existing research on the pot cover effect, the law of the water accumulation caused by the pot cover effect is studied for the road surface and runway, which have a structure of cover layer(equivalent to "pot cover"), gravel layer, and clay layer from top to bottom in actual engineering. Through carrying out indoor tests to simulate the road foundation structure of the actual project, the law of the water accumulation in soil, under the two conditions of open and closed, was analyzed respectively. The test results show that there is a phenomenon of water vapor circulation of the pot cover effect under the two test conditions, and the peak values of the water head circulation of the two tests are different. The internal mechanism of water vapor circulation was explained by the calculation of the water heads value. Calculating the circulating water volume of the closed system verified that the circulating water volume generated by the two tests in half of the cycle is approximately equal. It is found that the law of the water accumulation caused by the pot cover effect is related to whether the bottom of the gravel layer is flat. If the bottom of the gravel layer is not flat, the water in the gravel layer will keep accumulating. If the bottom of the gravel layer is flat, the water in the gravel layer just increases to a certain amount, the water volume will no longer increase, and a certain amount of water circulates in the form of water vapor in the gravel layer. Favorable road foundation structure should be designed in the project to prevent massive water accumulation under the road surface.