Construction Technology For Blasting Excavation Of Ultra-small Spacing Pass Under The High-speed Rail Tunnel

The rapid development of the national economy, and also contributed to the construction of transport facilities, but due to line construction land and geological conditions, tunnel overlap springing continue to emerge. Small Spacing Tunnels overlap force complex, difficult construction, how to effectively solve this problem has become a hot spot of concern to engineering.In this paper, the Shanghai-Kunming high-speed railway section in Guizhou small alpine tunnel passing under the ultra-small drain spacing small alpine tunnel excavation engineering background, theoretical calculation, numerical simulation and actual measurement signal meticulous analysis method,systematic study of the ultra-small wear under construction Neighborhood tunnel drilling and blasting vibration reduction technology, the establishment of a tunnel below the ultra-small spacing damping blasting technology system,security under the existing tunnel structure through the process of security,providing for construction of similar projects a valuable reference value. The main research work and results are as follows:1. According to the engineering and damping blasting theory design four blasting scheme, and its rock damage may be caused to do a theoretical calculation, while developing a sound blasting monitoring programs.2. By means of finite element software ANSYS/DYNA three-dimensional numerical model to study the mechanism of shock absorption and cushioning layer of shock-absorbing layer to optimize the design, and completed the simulation test at the new drain hole drilling and blasting through the process.3. To achieve the construction beneath the full monitoring, get a lot of valuable blasting vibration and acoustic test data.4. Wavelet packet+sound analysis fine method, analysis of the vibration signal from the vibration velocity amplitude and energy aspects.5. On the basis of the theory of partitions established on BP waveletnetwork model for predicting vibration near the tunnel area.6. Analyzes the changing circumstances surrounding rock scene acoustic velocity to obtain cumulative damage and blast rock loose circle range.7. Established of a ultra-small spacing tunnel below the damping technique system, it can be well applied in the tunnel construction under the guidance of ultra-small clearance, and effective security structure of the existing tunnels.