# Recognition of Tunnel Fracture Zones in Seismic Waves and Ground-Penetrating Radar Data
## 1 Introduction
[15] processed geological radar images by filtering, binarization, and refinement to make radar image recognition more accurate and mitigate the effect of noise on the image. The neural network pattern recognition technique was used to achieve the automatic detection of curved targets in B-scan images. In 2020, [PERSON] [16] used improved ground-penetrating radar to detect unknown geological features in front of a tunnel and identify more fractured rock masses. Their findings indicated that ground-penetrating radar is an effective tool for solving the problem of deep gold mining. In 2020, [PERSON] et al. [17] evaluated the detection capability of GPR for cracks. Their results indicated that GPR imaging can effectively detect open sub-horizontal fractures with submillimeter apertures. In 2023, [PERSON] et al. [18] used attenuation and reflection coefficients to determine the location of rebar's feature points with A-SCAN technology and superimposed them to display the selected rebar feature points on B-SCAN images. These authors thus realized the automatic identification and location of reinforcement in tunnel linings. In 2023, [PERSON] et al. [19] combined the reflection coefficient and attenuation coefficient characteristics of voids and constructed geometric features to identify voids. For the overcasting of tunnels, a variety of geophysical techniques are widely used for the prediction of fracture zones. In 2013, [PERSON] et al. [20] used the Dadu Mountain Tunnel as their research object and employed advanced geological prediction using TRT to obtain a three-dimensional seismic wave map. By combining this with the GPR geological prediction method, fault fracture zones and developments of karst fissures during the construction of the tunnel were comprehensively assessed. In 2015, [PERSON] et al. [21] integrated the application of GPR and geological drilling (Geo-D) techniques for tunnel overcasting. Their results indicated that through the joint analysis of two geophysical methods, the geometric characteristics of karst caves and their spatial relationship with tunnels could be identified and predicted. In 2019, [PERSON] et al. [22] conducted an advanced geological analysis of tunnels using geophysical methods, such as TSP, TEM [23], and GPR. The TSP method was first used for long-range detection to identify poor geology with geohazard risks. Then, the transient electromagnetic method combined with GPR was used to distinguish the bad geology. The results showed that the joint use of multiple physical exploration methods improves the accuracy of the prediction results. In 2021, [PERSON] et al. [24] utilized the advantages of TSP and GPR in distinguishing different geological bodies to conduct advanced forecasting and cross-validated the forecasting results. Their results showedthat utilizing the complementarity of long-range prediction and short-range prediction improves the accuracy of detecting the spatial locations of undesirable geological bodies. In 2023, [PERSON] et al. (2024) used a combination of the TST method and GPR to identify broken rock bodies and fissures in the rock surrounding a tunnel. Moreover, their results were verified with the tunnel excavation results and were found to effectively predict the existence of broken rock bodies and ensure the safety of construction. In this paper, the identification of fracture zones has been achieved by combining seismic wave and ground-penetrating radar detection data. The anomalous reflection points in the stack velocity spectrum with the characteristics of fracture zones are identified according to the seismic reflection signal, and a three-dimensional tunnel model is constructed to judge the area of the fractured rock mass in front of the tunnel face. The algorithm for the identification of fracture zones is realized based on the increased amplitude, increased center frequency, and phase change in the radar reflection waveforms that occur when electromagnetic waves contact a broken rock body.