地热勘察中地温测试关键技术分析

Analysis of the Key Technology for Ground Temperature Test in Geothermal Investigation

研究目的:拉日铁路在雅鲁藏布江峡谷区色麦至仁布段,近垂直地通过那曲—羊八井—尼木水热活动带,在铁路隧道的地热勘察中,采用钻孔内地温测试的方法对地温场进行评价,并对其地温测试关键技术进行总结和研究。研究结论:(1)拉日铁路地温测试的关键技术主要包括:地温测试元件选择、钻孔及孔内结构、测试时间以及数据处理;(2)地温元件选择热敏电阻,其精度高,操作简单,反复利用性强;(3)钻孔施工要注意孔斜控制,孔内要安装测温管以便地温测绳反复利用,地温测试时间在终孔后30 d为宜;(4)地温测试数据的处理主要包括:确定恒温带深度、大地热流值、隧道洞身温度推算等;(5)本文的研究成果可以为同类地区地热地温测试工作提供依据和借鉴,对地热勘察工作及地热研究有一定的参考意义。

In the Yarlung Zangbo Canyon, the Semai - Renbu section of Lhasa - Rikaze railway goes near vertically across the hydrothermal active belt of Naqu - Yangbajing - Nimu. In the engineering geologic investigation for railway tunnel of geothermal region, we use the ground - temperature test method in drilling - hole to evaluate the geothermal conditions. This paper summarizes and studies on its geothermal test＇ s key technology. Research conclusions： （ 1 ） In the geologic investigation of Lhasa - Rikaze railway, the key technology of ground temperature test mainly includes ： sensor for ground - temperature measuring, drilling - hole, the hole structure, test time and data processing. （2） It is suitable that the thermostat was choose as the sensor for ground - temperature test, with high precision, simple operation, well repeated use. （3）Pay attention to the hole deviation control in the process of drilling. Put the temperature tube in the drilling - hole, so that the temperature measuring cable can be repeated used. The temperature test time should be 30 days after the drilling. （4）The data processing about ground temperature mainly includes： determining depth of constant temperature layer, calculating the ground heat flux, forecasting the tunnel temperature, etc. （5）The results of this study can provide the basis and reference for geothermal ground temperature measuring of similar region, have certain reference significance to the geothermal investigation and geothermal research.