Basic characteristics and stability evaluation of dangerous rockmasses in Yanqi Town, Beijing

In this paper, taking Yanqi Town, Huairou District, Beijing as the research object, through the field investigation and rock block test and detection, the basic characteristics of the collapse are found out. By using the method of stereographic projection analysis, the overall stability of the collapse dangerous rock zone is qualitatively analyzed; by using the method of limit equilibrium, the single dangerous rock collapse is quantitatively evaluated according to different working conditions. On this basis, the targeted governance measures are put forward. The results show that: (1) the dangerous rock zone on the slope where the hidden danger point of collapse disaster is located is basically in an unstable state; (2) under the condition of self weight + fracture water pressure (natural state), the stability coefficient of single dangerous rock W1, W2 and W3 is 1.02～1.17, which are all in an unstable state; under the condition of self weight+ fracture water pressure (rainstorm), the stability coefficient is 0.82～0.98, both in an unstable state; under the condition of self weight + fissure water pressure (natural state) + seismic force, the stability coefficient is 0.72～0.83, both in an unstable state. (3) The comprehensive engineering control measures of “active + passive protection network” are feasible in Beijing area. The research results can be used as a reference for engineering control of collapse disaster in Beijing.