Abstract: With the continuous improvement and development of geological exploration technology, China's exploration work has made great progress. However, for areas with complex topography and geomorphology, how to select exploration methods and improve exploration levels is a problem that needs to be considered and urgently solved. Ground penetrating radar (GPR), as an advanced and effective exploration method, has been widely used in recent years, and its application range is constantly expanding. This article will discuss the feasibility of GPR in current geological disasters, focusing on the role and application of GPR in geological disaster exploration, hoping to provide readers with some inspiration.

Keywords: Geological disasters; Ground penetrating radar; Exploration; Technological application

With the continuous warming of the climate in recent years, the number of geological disasters has been increasing. Geological disasters are disasters that threaten or cause damage to human life and property due to geological action or human factors. Common geological disasters include landslides, collapses, debris flows, etc., which are potential threats to humans. We must strengthen the integrated research of science and technology, improve the exploration methods and levels of geological disasters, and reduce unnecessary economic and property losses caused by inaccurate geological disaster exploration and inadequate prediction. The occurrence of any geological disaster will cause changes in the geographical morphology and geophysical field of the corresponding region. Based on this principle, geophysical methods can effectively carry out geological disaster exploration. Therefore, the current research on the technological application of ground penetrating radar in geological disaster exploration is of great significance.

I. Feasibility of using ground penetrating radar for geological hazard investigation

There are many types of geological disasters, and the classification is also very different depending on the different classification standards. Simply put, geological disasters are mainly divided into natural geological disasters and man-made geological disasters. The inducing factors of natural geological disasters are mainly rainfall, snowmelt, earthquakes, etc., while man-made geological disasters are closely related to human production activities. The common geological disasters we often talk about refer to geological disaster movements that are closely related to six geological actions such as collapse, landslide, debris flow, ground subsidence, ground fissures, and ground subsidence, and that affect people's normal life and property. Common geological disasters include landslides, collapses, debris flows, soil erosion, etc. If each natural disaster cannot be predicted in time and effective protective measures are formulated, unpredictable negative consequences will occur. The occurrence of each geological disaster will leave corresponding reflections or traces on the geological environment of the corresponding area or the connected medium layer, which is the dielectric interface we often mention, the most common being fissures or sinkholes left after geological movement, etc. The physical properties of these medium layers are generally very different. Therefore, for this reason, if the geological layer is surveyed using certain methods, this dielectric interface can be found, and the accurate location and approximate shape of this interface can be interpreted, and the information people want to know can be obtained through relevant analysis. Practice has proved that ground penetrating radar can achieve this expected exploration effect, so it is feasible to use ground penetrating radar for geological hazard investigation. In addition, the high frequency, wide bandwidth, and short pulse characteristics of ground penetrating radar itself also make it have certain advantages in geological hazard exploration.

II. Application of ground penetrating radar in geological hazard investigation

1. Application of ground penetrating radar in ground fissure investigation

Ground fissures are a unique and relatively common type of geological disaster. Since the Tangshan earthquake in 1976, the activity intensity of ground fissures has increased significantly. In recent decades, excessive pumping of confined water and fractures have also directly led to the deepening of ground subsidence, which has also aggravated the occurrence of ground fissures to a certain extent. Due to the increasing frequency of ground fissures appearing on the surface, and the scale and width are becoming more and more subtle, some ground fissures can only be calculated in millimeters. Therefore, in order to investigate these small fissures that are not easy to notice, effective exploration and measurement methods must be adopted. When the stratum is affected by shear or tensile stress, the stratum will produce certain cracks and positional offsets. At this time, if radar is used for imaging exploration, the same-phase axis will appear to be broken in the radar image display. The greater the degree of breakage, the greater the width of the crack. In addition, if the radar detects ground fissures, the local waveform of the radar will also be distorted, and the frequency will also change. Therefore, the current application of ground penetrating radar has solved the problem of these relatively small fractures that are difficult to measure with ultrasound, and has played an important role in ground fissure investigation.

2. Application of ground penetrating radar in karst collapse investigation

Ground penetrating radar is a geophysical method based on the basic theory of electromagnetic waves, which uses antennas to transmit high-frequency, wide-bandwidth, short-pulse electromagnetic waves to the surroundings. It can detect some relatively hidden distributed media or predetermined measurement targets. When using radar to investigate karst collapse areas, if the bedrock surface is relatively complete, the continuity of the reflection wave's same-phase axis will be relatively normal, the wave group motion state will be good, and the signal will be relatively strong. For partial collapse areas or karstic development areas, when ground penetrating radar is used for investigation, the radar wave group display will show anomalies, the degree will increase, and the original continuous phase-rich hyperbolic motion will become irregular, which is also the main basis for judging whether karst has collapsed. For areas with highly soluble rocks such as limestone and dolomite, the probability of karst collapse is extremely high. On the one hand, it is due to water erosion, and on the other hand, it is caused by other factors that cause the expansion of caves. This type of karst collapse geological disaster generally occurs in relatively hidden areas, and the safety hazards are also very large. Therefore, based on ground penetrating radar technology, continuous strengthening of technical research in this area is necessary.

3. Application of ground penetrating radar in landslide investigation

Long-term river erosion, rainwater soaking, or intense groundwater activity can cause slopes to landslide, also known as "walking mountains" or "collapsing mountains". In areas with obvious or well-developed slope landforms, landslides are a relatively common geological disaster. This type of disaster is highly sudden and can also be said to be a secondary disaster of seismic activity, debris flows, etc. To analyze the causes and investigate landslide disasters well, it is necessary to first investigate and understand the landslide surface in areas where slope landforms are developed. In landslide hazard investigation, electrical methods and seismic exploration methods are also common exploration methods, but due to their high cost, their applicability is limited. The use of ground penetrating radar for landslide exploration is fast, efficient, and economical, so it has been well promoted and applied in recent years.

4. Application of ground penetrating radar in active fault investigation

Due to the unique nature of urban natural environments, coupled with increasing human activity and other influencing factors, conducting active fault investigation in this complex urban setting has become a critical issue requiring urgent attention. Active faults, as a significant and potentially devastating geological hazard, can easily trigger other geological movements and disasters, posing a serious threat that demands our utmost vigilance. If we can accurately locate and investigate active faults before they cause disasters, we can implement timely preventive and protective measures to minimize economic losses resulting from such geological hazards. In active fault investigation, we generally employ rapid, accurate, and highly effective methods. Traditional methods such as drilling and deformation monitoring are increasingly being replaced by ground-penetrating radar techniques.

Conclusion: Geological disasters have posed a serious threat to human life and property since the dawn of civilization. Despite rapid technological advancements, we cannot entirely prevent these disasters. Our best course of action is to effectively monitor geological movements and implement preventive and protective measures before disasters strike. Ground-penetrating radar, as a rapid, efficient, and economical detection method, has found widespread application in engineering construction and disaster prevention, playing an irreplaceable role in geological hazard investigation.