| Through field investigation and analysis of engineering geological data collection and relevant mechanical tests,the distribution and failure mode of unstable rocks in Xinjiubin,Zhangza Town,Jiuzhaigou County were analyzed and studied in the thesis.Based on the analysis and study of the distribution and development characteristics of the unstable rocks,the stability of the rock mass and the influence range and degree of rockfall on the rock mass are analyzed by stereographic projection and Rocfall numerical analysis software.We have put forward corresponding prevention management suggestions and the following conclusions:(1)The unstable rock body is located next to Provincial Highway 301 of Zhangza Town,Jiuzhaigou County.Excavating the foot of the side slope for the construction party causes the slope to become steeper,which artificially changes the original state of the slope,causes the unloading deformation of the foot of the side slope,causes the change of the side's air and mechanical state,and causes the slope to collapse.The slope was built with retaining walls at the foot of the slope.It was about 95 meters long and 2 meters high.The wall was a mortar block stone.(2)Most of the unstable rock mass is distributed at an elevation of 2,200 meters or more,and is located at the top of the collapse area.The area is directly exposed to the bedrock and is also the main source area of collapse disasters.The bedrock exposed by the slope is limestone,the surface rock mass weathering is strong,the fracture is developed,and the rock mass is broken.According to its spatial distribution,the collapse hazard area is divided into two unstable rock zones,namely WYD1 and WYD2.WYD1 is located on the West side of the slide and has an elevation of about 2210 to 2230 meters;WYD2 is located at the top of the slide range and has an elevation of 2220 to 2280 meters.(3)According to the field investigation and the analysis of the structure characteristics of the slope rock mass,the mechanism of formation of the slope rock is mainly divided into two types: toppling rock mass and falling rock mass.(4)Considering the development characteristics of dominant structural plane,the slope rock mass is analyzed by the method of stereographic projection,we come to a conclusion that the slope is in the basic stable state under the natural state,so it is necessary to clean the rock and pay attention to the prevention and treatment of weathering and rainfall.By using Rocfall numerical analysis software,it can be found that less rockfall falls onto or across the road,and the rock that passes over the road still has greater kinetic energy,which poses a threat to pedestrians and vehicles.In view of the characteristics of the dangerous rock mass,the paper puts forward some suggestions of cleaning the broken rock and gravel on the upper side of the slope,hanging protective net and spraying grouting on the unbroken dangerous rock mass,setting up stone blocking net on the lower side of the slope and other engineering measures. |
PDF Full Text Request