﻿ 电法勘探在黄土区洞穴探测中的应用 Application of Electrical Prospecting in Cave Detection in Loess Area

Vol.07 No.06(2017), Article ID:23079,10 pages
10.12677/AG.2017.76080

Application of Electrical Prospecting in Cave Detection in Loess Area

Zhengke Wang, Lin Lu, Jianrong Liu, Shaohu Hu

The Second Comprehensive Geophysical Exploration Brigade, Bureau of Geology and Mineral Resources Exploration and Development of Shaanxi, Xi’an Shaanxi

Received: Nov. 29th, 2017; accepted: Dec. 13th, 2017; published: Dec. 20th, 2017

ABSTRACT

The main cave detection way is electrical prospecting by the electricity differences. An example of cave detection can be used to explain the results which can serve the construction projects. The example is given that the shallow cave was detected under the condition of restricted working area. There are many detection methods for the cave being deeply buried (i.e. gob), such as gravity exploration, magnetic method and seismic prospecting. Each method has its own specialty and common characteristics. According to the characteristics of the cave or goaf, the reasonable detection method can obtain the ideal result by analyzing the physical condition of the cave or goaf.

Keywords:Cave Detection, High-Density Electrical Method, Electrical Device, Methods Study

1. 引言

2. 探测方法选择

2.1. 联合剖面法

${\rho }_{S}=K\frac{\Delta V}{I}$ (1)

$K=2\text{π}\frac{AM\cdot AN}{MN}$ (2)

2.2. 中间梯度法

$K=\frac{2\text{π}}{\frac{1}{AM}-\frac{1}{AN}-\frac{1}{BM}+\frac{1}{BN}}$ (3)

Figure 1. Diagram of resistivity profiling

Figure 2. Diagram of central gradient array method

2.3. 高密度电法

3. 实例应用

3.1. 电性特征

3.2. 试验工作

1) 以常规电法联合剖面法电阻率曲线的“反交点”来判断沿测线高阻体的水平位置，并由中间梯度法电阻率曲线进行验证；

2) 由高密度电法单极–偶极装置(其它装置数据量限制，显示的地电断面较为模糊或范围有限)地电断面图解释高祖体沿测线的水平位置和埋藏深度(垂向位置)；

3) 对于高密度电法地电断面图中的低电阻率(低阻)区域，由于其范围一般较大，边界不易判断，此勘探区的判断标准是将电阻率小于1 Ω∙m的区域圈定为渗井或窨井。

3.3. 探测结果

2#(图5图6)测线中联合剖面法显示的两个“反交点”与中间梯度测试结果的高阻异常对应，受浅部低阻异常(图5)S2影响使得低阻异常两侧呈现为两个局部高阻D5和D6。高密度反演结果显示D5深度 > 5 m，视电阻率大于1500 Ω∙m，呈似圆形且具有向东延伸趋势；D6异常深度 > 6 m，视电阻率大于1500 Ω∙m

Figure 3. The detection results of conventional electrical method on the 1# line

Table 1. The table of electric characteristics

Figure 4. The detection and explanation results of electrical method on the 1# line

Figure 5. The detection results of conventional electrical method on the 2# line

(由于场地限制，深部异常不完整)；D7异常深度5 m左右，视电阻率略大于背景值(80 Ω∙m)。S2异常呈近似等轴状，深度4 m，视电阻率 < 1 Ω∙m，判断为窨井渗水区。

Figure 6. The detection and explanation results of electrical method on the 2# line

Figure 7. The detection and explanation results of electrical method on the 3# line

Figure 8. The detection results of electrical method on the 5# line

3#测线所展布位置多窨井口。高密度电法异常有三处高阻(D8、D9、D10)和二处低阻(S3、S4)，结合实地调查及反演结果分析：D8为化粪池顶部的空旷区，D9为局部小空洞，D10为坍塌的空旷区；S3、S4地电断面不完整，从测线所处位置看，判断低阻异常区域与排水管和雨水导流管充水、渗水有关。

Figure 9. The detection and explanation results of electrical method on the 5# line

Figure 10. The detection results of electrical method on the 6# line

Figure 11. The detection and explanation results of electrical method on the 6# line

5#测线展布区域地下管道较多(窨井盖4处)。

6#测线与5#测线平行排列，联合剖面视电阻率曲线(图10)在0~50 m区间也为大于20 Ω∙m的高阻区，两条( ${\rho }_{s}^{A}$${\rho }_{s}^{B}$ )电阻率曲线(图9)近似平行排列。

4. 结论

Figure 12. The map of detecting explore

Table 2. The feature of the electric methods in the process of detecting caves

Application of Electrical Prospecting in Cave Detection in Loess Area[J]. 地球科学前沿, 2017, 07(06): 786-795. http://dx.doi.org/10.12677/AG.2017.76080

1. 1. 彭建兵. 黄土洞穴灾害[M]. 北京: 科学出版社, 2009.

2. 2. 赵伟, 张青山, 杨锋. 浅层地震与静力触探方法在黄土洞穴探测中的应用[J]. 河南交通科技, 2000(4): 10-12.

3. 3. 傅良魁, 主编. 电法勘探教程[M]. 北京: 地质出版社, 1983.

4. 4. 中华人民共和国地质矿产行业标准. 电阻率剖面法技术规程DZ/T 0073-93[S]. 北京: 地质出版社, 1994.

5. 5. 李金铭, 罗延钟, 主编. 电法勘探新进展[M]. 北京: 地质出版社, 1996.

6. 6. 王妙月, 等. 勘探地球物理学[M]. 北京: 地震出版社, 2003.

7. 7. 王怀坤, 罗有春, 等. 高密度电法对横向目标体勘探效果比较[J]. 华南地质与矿产, 2008(2): 62-66.

8. 8. 刘春华, 等. 高密度电法勘探在高速公路勘察中的应用[J]. 山西能源与节能, 2010(5): 29-31.

9. 9. 刘金涛, 胡晓明. 高密度电法勘探在岩溶查找中的应用[J]. 地质科技情报, 2003(2): 100-102.

10. 10. 李清林, 秦建增, 谢汝一, 等. 地电成像及其在地学领域中的应用研究[M]. 北京: 地震出版社, 2010.

11. 11. 李喜安, 彭建兵, 王军. 湿陷性黄土区黄土洞穴对公路的危害研究[J]. 陕西建筑, 2005(2): 19-23.

12. 12. 彭建兵, 李喜安, 范文, 等. 黄土高原地区黄土洞穴的分类即发育规律[J]. 滴血前缘, 2007(6): 234-244.