Methods and contents of geological safety evaluation for urban underground space development and utilization

Geological safety evaluation of urban underground space is the basis for the development and utilization of underground space resources. However, the content, principle and method of the evaluation have not been systematically studied. Aiming at serving controlling detailed planning and construction detailed planning, this paper puts forward three aspects of the evaluation of geological safety for the development and utilization of urban underground space. One is the evaluation of self-stability of underground space and the calculation method of surrounding rock stability by subsurface and deep buried caverns is used. Based on the modified Fenner formula, the surrounding rock stability calculation method is proposed, in which the surrounding caverns shear plastic limit surface just reaches the critical condition of the surrounding rock stability. At the same time, geological models are built to simulate the caverns stability under different working conditions, a large sample database is obtained and the neural network method is used. Therefore, a new rapid underground space self-stability evaluation system is established. Second, the evaluation of stability of adjacent engineering caused by the development of urban underground space is sorted out from two aspects, including the influence of underground space development on surface engineering, and the influence between underground engineering. The third is the evaluation of the impact of the post-construction surface engineering on the stability of underground engineering by the methods of in-situ monitoring, numerical analysis and engineering analogy.