Research On Rock Block Development Law Of Highway Slope In Beijing Area

With the integration of Beijing-Tianjin-Hebei,coordinated development of Beijing-Tianjin-Hebei will inevitably lead to transportation.When constructing highways,a large amount of manual excavation is usually required for road sections passing through mountain areas.At this time,the discontinuities and excavation circles in the rock,many large-scale rock blocks have been formed due to the closure,losing the original static equilibrium state of the rock and destroying the integrity of the rock.These blocks may even collapse on a large scale,resulting in a series of geological disasters and seriously affecting the highway Construction and endanger the personal safety and daily life of residents.Based on Beijing,this paper qualitatively and quantitatively describes the distribution of fractures in field,conducts block identification and block research on rock blocks of highway slopes in Beijing,and masters the block development rules of different rocks in different locations in Beijing.To predict the characteristics of rock masses on highway slopes and provide technical support for the design of highway slopes in Beijing.The research results provide effective services for the expansion of Beijing's urban scale,economic construction and sustainable development.In the four districts of Fangshan District,Changping District,Huairou District,and Miyun District in Beijing,the paper selected 16 roadside rock mass outcrops for field exploration,and obtained basic data for the study of fractured rock mass.It is concluded that the selected rock masses are mainly developed with high-angle cracks,and most of the developed cracks belong to very low ductility fractures,and the dominant orientation of the crack development of each group of rock masses is obtained.The development orientation of the fissures differs greatly,indicating that the development characteristics of the fractures are controlled by stratigraphic lithology and tectonic movement.Fracture Grouping software is used to group the rock fractures according to the direction of the fractures,and the distribution parameters of the fracture occurrence are fitted by the Fisher distribution function.The inverse modeling method(Joint-OKY software)was used to obtain the average diameter,standard deviation and three-dimensional density of each group of fractures,and a three-dimensional discrete fracture network model of rock mass was established and the accuracy of the model was verified.The rock fracture network model established by the paper successfully reflects the actual distribution of rock fractures on highway slopes and can be used for the research of rock block research.Based on the general block method as the theoretical basis,Through the General Block software,the rock on the slope of Beijing Highway was researched into blocks.Under natural conditions,the percentage of sandstone blocks in Fangshan District was 0.00587%,the percentage of dolomite blocks in Changping District was 0.0000272%,and that of granite blocks in Huairou District was 0.00279%,the percentage of gneiss blocks in Miyun area is 0.00178%,the blockiness of rock both are very low and can be classified as non-massive rock mass.It is extremely low and belongs to non-bulky rock mass.It can indicate that the rock mass in Beijing area is relatively stable under natural conditions.