|
In recent years, the rapid development of the national economy, large-scale construction of high-speed railways, highways, urban rail transit project, is also increasing the number of long tunnel, the progress of the tunnel construction, tunnel construction safety often become a bottleneck to control the progress of the whole project. In order to ensure efficient tunnel construction, security incidents to avoid the blind construction sudden water, sudden mud, landslides, and reduce the economic losses, Front of Face adverse geological conditions become urgent need to address the problem of how to accurately understand. To this end, a variety of tunnel geological prediction method came into being. TSP seismic reflection wave method based on seismic reflection wave theory of seismic waves generated by excitation with a small amount of explosives in the tunnel sidewall, spread to the rock body, local shock waves encounter formation interface, Relay face, especially fault fracture zone column, silt with poor geological interface and the fall of the karst, underground river, karst part reflected back by the sensor receiver, the other the partially transmissive into the front of the media continue to spread, combined with survey and design data, geological data and geophysical data, a comprehensive analysis of the reflected wave signal characteristics and rock parameter attributes, you can find out the location, size and occurrence of adverse geological interface Front of Face. The detection accuracy of the method, the detection distance, capable of detecting adverse geological conditions in front of the tunnel face about 100m ~ 200m range. The current TSP seismic reflection wave method in tunnel construction geological prediction there exist some problems, the main problem is the the adverse geological interpretation of the lack of clear interpretation signs, more dependent on experience; surrounding rock engineering category unreliability. Therefore, the current technology in the theoretical analysis, data acquisition technology, forecast accuracy, reliability needed to further improve. This article focuses on the basic principle of the law of the TSP seismic reflection wave TSP-site work, TSP data processing flow, and to explore the feasibility of improving data quality approach, Finally, a typical engineering example, on the basis of the results of previous studies, initially established a TSP tunnel prediction determine karst and fault fracture zone two typical adverse geological image of the reflected wave characteristics. Achieved understanding is as follows: (1) a comprehensive analysis of evaluated various tunnel prediction method, TSP method to seismic waves reflected wave method for the basic theory With effective information and numerical analysis of the reflected wave rock properties parameter values, fast accurate positioning of the Front of Face adverse geological body position, size and occurrence. A large number of engineering practice shows that the applicability and effectiveness of the TSP system in the detection of adverse geological karst and fault fracture zone. (2) through hundreds of times TSP experience in the field data acquisition, and the TSP data processing in each step of the analysis, feasibility approach found to improve the quality of the data, and In the TSP data processing, the principle of each method to study and Applications so that the final generated two-dimensional results map more precisely. (3) The TSP system is applied to the Swiss railway, Jade Mongolian Railway, Mu new highway and Wenchuan highway, through comparative analysis on the 2D achievement chart as well as the parameters change, on the basis of the results of previous studies, preliminary summed up a TSP tunnel prediction of karst and fault fracture zone judgment interpretation signs.
|