Orthogonal numerical simulation on stability of urban underground cavities

The effects of cavity shape factors and mechanical parameters on the stability of underground cavity are studied by orthogona l numerical simulation test. According to the characteristics of underground cavities in the city, the orthogonal numerical values of six factors and five levels are carried out by selecting the factors such as cavity span, cavity height, overlying soil thickness, pavement load, cohesive force and interna l friction angle. The comprehensive evaluation model of multi-index orthogonal simulation test based on index satisfaction is set up, and four indexes of roof settlement, minimum principal stress, maximum principal stress and plastic zone volume are selected to study the multi-index comprehensive evaluation and sensitivity analysis. The results show that the pavement load and void span is the most sensitive to the stability of underground cavity. The cohesion and thic kness of overlying soil are the second sensitive cause, and the influence of cavitation height and internal friction angle are the least.