Methods and Practices for the Investigation and Risk Assessment of Geo-hazards in Mountainous Towns

Mountainous urbanization, new rural construction, rural revitalization and poverty alleviation are facing the threat of geo-hazards. It has a great strategic significance to carry out large-scale geo-hazards investigation and risk assessment to control geo-hazards risks from their source. Based on the pilot survey and assessment, this paper puts forward a set of ideas and technical methods for the investigation and risk assessment of geo-hazards in mountainous towns. Investigation and risk assessment of geo-hazards in mountain towns can be divided into 3 levels according to the purpose and scale accuracy. ① Investigation and risk assessment of regional remote geo-hazards, assessing the possibility of remote geo-hazards in mountainous towns, at scale of 1:50,000. ② Investigation and risk assessment of urban geo-hazards to investigate and assess the possibility and consequence of deformation and instability of surveying each slope and valley in the surrounding areas of mountain towns, with a scale of 1:10,000. ③ Investigation and risk assessment of important site geo-hazards to assess the possibility and consequence of deformation and damage of slopes and valleys around important sites, such as major construction projects and tourist attractions and evaluating the possibility of instability and the degree of damage. with scale range from 1:5,000 to 1:2,000. Each level has been explained in this paper from the aspects of contents, methods and processes of geo-hazards investigation and risk assessment. Taking the typical mountainous towns the Qinba Mountain Area in Southern Shaanxi and Loess Plateau Area in Northern Shaanxi, as the study areas the demonstrative application demonstration of geo-hazards investigation and risk assessment in mountainous towns was established.