隧道含水构造地面—地下瞬变电磁探测方法与响应规律研究

发布时间：2018-01-27 02:02

本文关键词： 瞬变电磁地井装置多分辨网格时域有限差分模型试验　出处：《山东大学》2017年硕士论文　论文类型：学位论文

【摘要】：我国的隧道建设目前面临严重的突水突泥威胁隐患,常用的方法是超前地质钻孔结合地球物理方法对隧道前方的地质情况进行判断。但是,目前的超前地质预报方法仅仅能够获取掌子面前方一定范围内不良地质体的情况,无法识别隧道掌子面前方大规模的不良地质构造,对隧道顶板和底板不良地质体的探测手段有限;受到隧道内台车、钢拱架等低阻异常的干扰,电磁类方法信噪比较低;在隧道选线勘察时,缺乏有效探查大规模不良地质体的地球物理手段。因此,类比地空瞬变电磁装置型式,地面-地下瞬变电磁装置型式将发射源布设于地面,在地下和地面接收响应信号。发射源布设于地面,距离隧道内金属异常体较远,相比隧道内布设发射源能够提高信噪比;该装置能够探查几十米甚至数百米的不良地质构造,并且能够探查已开挖隧道顶板和底板的地质构造情况;隧道选线时可以应用该装置探查大规模不良含水地质体,测深能够达到千米以上。地面-地下瞬变电磁法扩大了瞬变电磁在隧道超前地质预报的探测范围,有望成为隧道超前地质预报的新手段。本文的主要思想是将地面-地下瞬变电磁探测方法引入隧道超前地质预报与前期勘察中,全面阐述了该装置型式的特点,系统介绍了如何地面-地下接收数据。为了研究地面-地下瞬变电磁法对不良地质含水体的响应特征规律,首先对多分辨网格算法进行了开发,对多尺度网格内部的迭代公式进行了重新定义,利用多尺度网格的边界条件对运算关系进行制约,实现了时间域与空间域运算关系的统一;然后通过改变接收深度、电阻率和收发距探究均匀半空间模型地面发射-地下接收瞬变电磁的基本规律,对垂直方向、轴向方向等五个方向的进行测线优选;最后探究了纯隧道腔体、直立充水断层、倾斜充水断层、充水溶洞、断层破碎带和大规模地下暗河的响应规律。在数值计算的基础上,利用物理模型试验模拟了地面发射-地下接收瞬变电磁的响应规律,首先利用不同收发距、接收高度、发射线圈位置的物理模型试验得到基本响应规律;然后利用顶底板及直立断面低阻异常断面分别得出顶部低阻异常、底部低阻异常、直立低阻异常的响应规律特征;最后利用掌子面前方不同含水体模型试验得出直立含水体、倾斜含水体、立方含水体的响应规律,对不同水量的响应特征进行分析归纳。在数值计算和物理模型试验的基础上进行了现场试验,首先,对已知水仓进行地面和地下数据采集,利用已知模型验证地面-地下瞬变电磁的可行性;其次,对未知区域进行地面发射-地下接收数据采集,利用巷道内小回线瞬变电磁法进行结果验证;第三,对未知采区进行地面发射-地面接收瞬变电磁试验,利可控源方法进行结果验证。通过数值模拟、物理模型试验和现场试验得出,地面-地下瞬变电磁装置型式对含水地质体响应特征明显。本文通过多分辨网格算法开发、数值模拟、物理模型试验和现场试验研究了地面-地下瞬变电磁法,得到该装置型式下不同异常含水体的响应特征,为后期的瞬变电磁三维反演奠定了基础。
[Abstract]:The tunnel construction in our country is currently facing a serious threat of water mud inrush hazard, the commonly used method is the geological conditions of geological drilling with geophysical methods in front of the tunnel to judge. However, geological prediction methods at present can only get in front of the tunnel face a range of adverse geological conditions, unable to identify the tunnel face our big bad geological structure, detection means of the tunnel roof and floor of the adverse geological Co.; by tunnel trolley, steel arch etc. low resistivity abnormal interference, electromagnetic method of low SNR; line selection investigation in the tunnel, the lack of effective exploration of large-scale adverse geological geophysical methods. Therefore, analogy air ground transient electromagnetic device type, ground and underground transient electromagnetic device type will be arranged on emission source ground, underground and ground receiving response signals. The emission source in the layout Ground distance tunnel metal anomaly is far, compared to the tunnel layout emission source can improve the SNR; the device can bad geological structure exploration of tens of meters or even hundreds of meters, the geological structure and to probe the top and the bottom of the existing tunnel; tunnel line selection can be applied to the device exploration of massive bad aquifer plastid, sounding can reach kilometers above the ground. The underground transient electromagnetic method to expand the detection range of the transient electromagnetic geological prediction in tunnel, is expected to become the new tunnel geological prediction. This is the main idea to the ground and underground transient electromagnetic detection method into the tunnel geological prediction and pre survey. A comprehensive exposition of the characteristics of the device type, the system introduces how to ground and underground receiving data. In order to study the ground and underground water of bad geological transient electromagnetic method. Should the features, firstly, multi-resolution grid algorithm was developed, the iterative formula of internal multi-scale grid redefines the relationship of operational constraints using multi-scale grid boundary conditions, the realization of the unity of time domain and space domain calculation; then the receiving depth by changing the resistivity and receiving distance on basic the law of uniform half space model of ground and underground transient electromagnetic emission receiver, the vertical direction and the axial direction five line selection; finally explores the pure water filled tunnel cavity, vertical inclined water filling fault, fault, karst cave, underground river and large-scale response law of fault fracture. In the numerical simulation, the ground response law of underground transient electromagnetic receiver using the physical model test, using different offsets, receiving height, transmitting coil position The physical model test basic response law; and then use the top and bottom plates and vertical sections of low resistivity section were obtained at the top of the low resistivity, the low resistivity, low resistivity response characteristics of vertical characteristics; finally in front of the tunnel face with different water model experiments of water containing water containing upright, inclined, response of the water cube the response characteristics of different water content are analyzed in this paper. The field test, based on numerical calculation and model test on the first, ground and underground data acquisition of the known water sump, using the known model to verify the feasibility of ground and underground transient electromagnetic; secondly, the unknown area of the ground and underground receive data collection, using the roadway within the small loop transient electromagnetic method to verify the results; third, the ground launch ground receiving transient electric magnetic test of the unknown area, can Source control method to verify the results. Through numerical simulation, the physical model test and field test, the ground and underground transient electromagnetic device type of water containing plastid response characteristics is obvious. This paper developed multiresolution mesh algorithm, numerical simulation, experimental study on the ground and underground transient electromagnetic method to test physical model test and field response. The characteristics of device types under different abnormal water, laid the foundation for the latter part of the transient electromagnetic inversion.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U452.11;P631.325

【相似文献】