宝坻新井不同深度水温变化特征及异常机制分析

Water Temperature Variation and Anomaly Mechanisms at Different Depths in Baodi New Well

基于宝坻新井21个层位的水温实验资料,综合分析各个层位水温的固体潮形态、梯度变化、观测资料的灵敏性和稳定性,认为该井水温变化特征在深度上分为三段,其中以中间段资料的综合质量较好,且这三段与井孔的第四系覆盖层、基岩顶界到出水段深度和出水段的深度相当。通过对不同深度水温变化特征及其原因的分析认为,井孔中水温是围岩温度、垂向热传导、水热交换等影响因素共同作用的结果,而在不同深度起主导作用的因素也不同,因而使得井水温度在不同深度表现出不同的变化特征。同时结合该井曾经观测到的震前异常变化来对水温异常机制进行分析,认为井水温度的升高并不是由涌入井孔内的水量变化引起,而应该是吸收了更多的热量。最后在综合以上几点认识的基础上,指出宝坻新井水温观测的优势层位。

In this paper, experimental water temperature data from 21 different depth layers in the Baodi new well are analyzed. Results show that the water temperature gradient can be divided into three sections and that the data from the middle section are the most sensitive and stable. Through comparative analysis of the water temperature variation characteristics and causes, we found that the temperature variation. in the well is affected by the interaction of different factors , i. e. temperature of the surrounding rock, vertical heat conduction, and hydraulic and the- modynamic exchange. At different depths different factors play a leading role, so the temperature displays different characteristics. At the same time, by integrating the anomalous variations in water temperature before earthquakes, we perform a simple analysis on the mechanism of well- water temperature anomalies. Based on the above conclusions, we also point out the optimum layers for water temperature observation in this well.