聚焦电流法隧道地质前探仿真研究

发布时间：2018-01-05 00:11

本文关键词：聚焦电流法隧道地质前探仿真研究　出处：《华中科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：直流电阻率隧道超前探测法具有较高的勘探效率、野外操作施工简单方便等特点,在侧向测井、隧道超前预报、矿井勘探、城市地下交通工程中得到了较广泛的应用;但是,直流电阻率法在进行隧道超前预报时易受坑道、旁侧干扰的影响,而随着BEAM系统的出现,聚焦电流法吸引了越来越多科研工作者的目光。本文沿用聚焦电流法,应用ANSYS软件对聚焦电流法的探测原理、电场分布、电极连接方式、模拟实验中土箱形状及位置进行仿真研究,并进行了供电测量系统的设计以及现场试验。首先对传统三极法隧道前探效果进行了仿真分析,发现测量电位在与异常体距离掌子面相同半径处并没有明显的电阻率异常,说明直流电阻率法对异常体位置及电性的判断存在一定的误差。接着介绍了聚焦电流法的理论基础与探测原理,提出一种综合模式和扫描模式测量系统,并对聚焦电流法的探测原理进行了仿真分析。其次提出一种供电测量电极与屏蔽电极的连接方式,将护盾与滚刀测量电极之间以一个小电阻r相连接,采用经护盾向滚刀供电测量电极供电的方式,这样既能保证屏蔽电极与测量电极电位的相等,又避免了屏蔽电极电压的反馈控制,并通过仿真模拟的方法验证了该测量方式对异常体定性判断的可行性。然后对聚焦电流法土槽模拟实验中土槽的形状及位置进行仿真研究,一共选取球形、圆柱形、圆锥台形三种不同形状并且不同位置的模拟土槽与无限远地质条件下的模型进行比较,最后得出圆锥台形土箱并且中心位置按一定条件偏移的土箱形状可以较大限度的接近无限远地电条件电场分布,并且易于加工。最后,设计了一个完整的测量系统,该系统由变频信号产生模块、恒流驱动模块、微机系统、数据采集模块构成,并在实验室环境、武汉机场、西安引汉济渭等项目中进行了测试。
[Abstract]:DC resistivity tunnel advance detection method has the characteristics of high exploration efficiency, simple and convenient field operation, and so on. It can be used in lateral logging, tunnel advance prediction and mine exploration. Urban underground traffic engineering has been widely used; However, the DC resistivity method is easy to be affected by tunnel and side interference in tunnel advance prediction, and along with the emergence of BEAM system. Focusing current method has attracted more and more researchers' attention. In this paper, the detection principle, electric field distribution and electrode connection mode of focusing current method are studied by ANSYS software. In the simulation experiment, the shape and position of the earth box were simulated, and the design of the power supply measurement system and the field test were carried out. Firstly, the simulation analysis of the traditional three-pole method tunnel before detection effect was carried out. It is found that there is no obvious resistivity anomaly at the same radius between the measured potential and the anomalous body from the palm surface. It shows that the DC resistivity method has some errors in judging the position and electrical property of abnormal body. Then the theoretical basis and detection principle of the focusing current method are introduced and a comprehensive mode and scanning mode measurement system is proposed. The detection principle of focusing current method is simulated and analyzed. Secondly, a kind of connection mode between the power supply measuring electrode and the shield electrode is proposed. The shield is connected with the hob measuring electrode with a small resistance r. The shield is used to supply the measuring electrode to the hob, which can not only guarantee the equivalence between the shield electrode and the measured electrode potential, but also avoid the feedback control of the shield electrode voltage. The feasibility of the method is verified by simulation. Then, the shape and position of the earth trough are simulated in the focused current method, and the spherical shape is selected. Three kinds of simulated soil grooves with different shapes and different positions are compared with the models under infinite geological conditions. Finally, it is concluded that the shape of the earth box with conical platform shape and center position shifting according to certain conditions can be close to infinite electric field distribution, and is easy to process. A complete measurement system is designed. The system is composed of frequency conversion signal generation module, constant current driving module, microcomputer system, data acquisition module, and in the laboratory environment, Wuhan Airport. Xi'an introduced Han to Wei and other projects were tested.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.3;U452.1

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