Research On Road Collapse Risk Assessment Based On GIS And Multi-attribute Decision Method

In recent years,urban road collapse accidents occur frequently,which causes huge economic loss and human injury.At the same time,the current measurements of prevention and management of ground collapse is far from perfect.Therefore,effective risk assessment,reasonable and comprehensive field radar detection and systematic information management are of great significance to the prevention and control of ground collapse disaster and the safe operation of the city.The basic characteristics and formation mechanism of ground collapse are summarized in the thesis.Then,three categories of factors resulting in ground collapse,i.e.,engineering factors,underground pipe network and environment geological factors are discussed.Subsequently,the disaster vulnerability factors,post-disaster impacts factors and the emergency vulnerability factors are selected and adopted for risk assessment.Finally,as a case study in Bao’an District,the surface collapse risk assessment index system is established.The currently used methods for the risk assessment of urban road collapse are relatively lean and insufficient consideration of their fuzziness,randomness and complexity.To deal with this issue,an AHP-EWM-Cloud model is proposed in this thesis.First,the AHP is used to construct the decision hierarchy and give the initial weights of various variables,then the EWM(Entropy Weight Method)is adopted to reconstruct weights,which are more objective.Subsequently,the cloud model is used to construct the risk standard,and its digital characteristics and cloud map are adopted to describe the uncertainty and randomness of ground collapse risk.Finally,the model is applied to the collapse risk assessment of six roads in Bao’an District from small-scale units to the whole road.The assessment results are compared with the measured results of ground penetrating radar(GPR),which validates the applicability and feasibility of the model.To identify the potential hazards of the road surface collapse caused by drainage pipe leakage,the ground penetrating radar detection and underground pipe radar detection are combined to comprehensively investigate the hidden danger of collapse around the drainage pipe.In order to realize the information management of ground collapse,taking Bao’an District as an example,the risk assessment system of ground collapse is designed and realized.The system can manage the hidden danger data of ground collapse and historical accident data,visualize the risk assessment results based on GIS,and conduct auxiliary excavation analysis and impact analysis of ground collapse.The model,detection and system constitute a complete chain of study of the risk of urban road ground collapse.It provides a new idea for the risk assessment of ground collapse and scientific guidance and targeted detection scheme for field GPR detection,and helps for information construction of ground collapse as well.Therefore,it is of significance to the comprehensive prevention and control of urban road surface collapse disaster,and the safe operation of the city.