For tackling a series of technical challenges of safety guarantee caused by the kinetic load of the urban underground project, including hazard monitoring, prevention, accident controlling, and rescue, the related technologies and theories are being undertaken for lifting the safe-guarantee capability of urban underground space:

(1) Multi-parameter & full-field detection and analysis of dynamic load damage of wall rock in underground space

 Set up comprehensive hazards assessment, analysis, and prediction system, and directional quantify the blasting damage to wall rock, establishing multi-parameter & full-field precise detection system serving from micro to macro.

 Realize high-precision sampling for in-place displacement (μm~m), stress, and temperature (-20°C ~ 2500°C).

 Undertake the multichannel vocalization test, drilling exploration, ultrasonic detection, and CT of large-scale rock establish an integration system of dynamic damage assessment & analysis module and online damage warning module.

(2) The safety assessment theory and technique of novel digital detonation used in the underground project

 Develop the failure detection technology of intelligent digital detonators, enhancing the safety and reliability of the initiation system.

 To assess the impact of slingshots and bulge on equipment failure, and to ameliorate that, study the theory about failure coupling effects among shock wave overpressure, blasting parameters, and digital detonation on different types of the fracture surface.

(3) The blasting vibration controlling technique for sophisticated urban underground condition

Set up the low vibration speed with precise controlling blasting technical system for the urban area, based on:

 Reconstruct the borehole vibration waveform in the vicinity of the blasting area according to the distance of the blasting center.

 Propose the vibration synthesis method of near-zone borehole delay blasting to solve the challenge of safe blasting in large-section and small-spacing tunnels.

 Develop the technologies of interference decreasing vibration and open face decreasing vibration for the structures far from blasting.

(4) The directional fracture controlled blasting theory and technique for urban underground project

 Reveal the evolutional laws of cumulative blasting vibration field in terms of time and space perspectives by analyzing the spreading of blasting shock waves and explosion gases.

 Based on the engineering and service features of the underground project.

 Study the fine-structure characteristics of shaped charge detonation wave front propagating in the airflow field.

 Generate the accurately controlled blasting theory and technical system for urban underground space.

 Explore the annular pressure field variation laws formed by cumulative blasting by testing the overpressure across air shock waves.

 Reveal the controlling principles of blasting energy release and expansion of burst cracks.

 Explore and take advantage of the controlling effects of dynamite structure on releasing blasting energy.

(5) Efficient driving blasting technology for urban underground project

 For lifting the driving efficiency of the underground rock project:

 Develop quasi-wedge compound blasting technique with ultra-deep borehole.

 Develop two-step cut blasting and shaft sectional cut blasting techniques.

 Reveal the formation mechanism of the second free face on the critical cutting area.

 Explore the relationship between the explosion resistance of rock and the rock-breaking ability of dynamite.

 Propose the optimal ultra-deep cutting coefficients and the representation approach for the mechanical characteristics of wall rock.

 Study the effect of micro-difference time and subsection ratio on energy distribution and full-field strain of subsection blasting in the shaft.

 Study the interactive relationship between explosive stress waves and explosion cracks.