Rockslide And Rockfall Risk Assessment For Cut Slope Along Road

Mountainous road in the Mentougou Region frequently exposed to the rock fall and rockslide that affect the safty of traveling public. It is a problem faced by the department oftransportation that how to prioritize remedial work of the hazard in order to maximizereducation of the risk to traveling public, minimize the costs and traffic disruptation.Qualitative or quantative risk assessment of rockfall and rock slide hazards can give an aid tothe the department of transportation for the management of hazards and decisions toeffectively impove the maintenance benefit-cost.The thesis designs the rock fall and rock slide risk rating system based on the existingsystem, geological condition in the Mentougou region and the historical rockfall and rockslidehazards of cut slopes along the mountainous roads, and then applies it to assess the rockfalland rockslide risk along the typical road, G109National Road. The result helps thedepartment of transportation to allocate the correct proportion of resources to the treatment ofeach group of hazards so as to maxinmize the reduction of risks. The main conclusions are asfollows:1. Reviews the exiting rockfall hazard rating systems and unstable slope managementsystems at home and abroad, points out their pros and cons.2. Analyses the geological and environmental information corresponding the conditionproning to rock fall and rock slide.3. Analyses the historical hazard inventory, and studies spatial-temporal distribution ofthe hazard and the affected fators of rockfall and rock slide.At the same time, illustrates thetransportaion impact of historical rockfall and rockslide hazards.4. In order to effectively manage unstable rock slope with problem of rock fall and rockslide,the thesis groups the rockmass of unstable rock mass into two categories, respectivelylocated unstable rockmass and random unstable rockmass.The located unstablerockmass,,divided by persistent and impersistent discontinuities, more than10m~3,is fromedby III and larger than the III discontinuities,whose failure model mainly are planefailure,wedge failure, topple failure and circular failure.Random unstable rockmass isconstituted by the less than10m~3rock blocks,which is formed by IV and the smaller than IVdiscontinuities or are deluvial block on the slope surface.Random unstable rockmass’ failuremode include single block failure and many blocks failure,but it is not certain that which one or group ot them fail.5. Provides quantified estimates method of GSI(Geological strength index) value，anddesigns the calculational program.6. Constructs the rock fall and rock slide risk rating system.Rockfall and rockslidehazards are assessed by comprehensive methods which include merit of slope stability anlysismethods and slope mass rating system.Consequence assessment of slope failure based onfuzzy comprehensive evaluation includes the impact factor related to the volume of potentialunstable rockmass,the height of the unstable rockmass and daily traffic volume. Riskassessment is finished by the risk matrix.7. Assesses the typical road in the Mentougou Regjion,the G109National road,andfound this methods is reliable,and satisfies the need of the administration to prioritize thehazards.and to effectively allocate the resources.The research result technically helps the department of transportation in the MentougouRegion to make the decision about allocating correct proportion of the resorce to thetreatment of each group of hzards. Meanwhile, the risk assessment methods gives a helpfulreference about the risk management of rockfall and rockslide hazard in the mountain terrain.