Deformation characteristics and treatment measures of dangerous rock collapse in an expressway in Chongqing

In this paper, five dangerous rockfall collapses at K1515 of the Shanghai-Chengdu expressway are taken as the research object. Through investigation, statistics, and analysis, the engineering geological conditions and developmental deformation characteristics of the dangerous rockfall collapse area are clarified. The research results show that: (1) the failure modes of dangerous rock masses W1 and W2 are misbreaking and cracking, the destruction mode of W3-1 dangerous rock mass is dumping, the destruction mode of W3-2 dangerous rock mass is sliding, and the destruction mode of W4 and W5 is bulging; (2) the stability coefficient of W1 and W2 is 1.12 and 1.61 respectively, which are in basically stable ~ stable state; the stability coefficient of dumping failure of W3-1 is 0.41 and in unstable state; the stability coefficient of sliding failure of W3-2 in W 3-2 is greater than 1.35 and in stable state; under rainstorm condition; the stability coefficient of bulging deformation of W4 and W5 is 1.25 and 1.15 respectively, which are in basically stable state; (3) The authors summarize the governance strategy of “reduce risk, minimize disturbance, ensure safe stability and feasible technology”, and adopt comprehensive remidiation measures of “embedding concrete retaining wall at the toe of slope + local active SNS network protection + prestressed anchor protection”, and the treatment effect was good. It can provide reliable reference basis for the treatment measures of dangerous rock collapse.