Study On Stability And Pre Reinforcement Measures For High Slope Of Rock Excavation

With the rapid growth of the national economy,China’s highway construction has been unprecedented development,steep mountain topography and complex geological structure inevitably bring a series of difficult problems to highway construction,highway rock steep high slope stability and pre-reinforcement issues have attracted much attention.Although some achievements have been made in the study of high rock slope at present,there are still many problems in the process of manual excavation.Therefore,it is of great engineering significance to study the stability and pre-reinforcement measures of high rock slope.Taking Mian-Guang Expressway K226+240 slope as an example,this paper studies the high slope of the project,analyzes the structural characteristics,deformation phenomena and stability of the slope,and puts forward the pre reinforcement measures of the slope,which has a good guiding significance for similar projects.The main contents and results are as follows:(1)According to the engineering geological conditions of the slope,the structural characteristics and deformation phenomena of the slope are analyzed,and the influence of the structural face on the stability of the slope is studied.At the same time,the corresponding engineering geological model is established.(2)By qualitative analysis,the main engineering geological problems faced by the slope are judged,the factors influencing the stability of the excavated slope are studied,and the stability of the excavated slope before pre-reinforcement is analyzed.According to the engineering characteristics and geological conditions of the whole slope,the reinforcement measures of the pre-stressed anchor cable anti-slide pile with better reinforcement effect than the anti-slide pile and the pre-stressed anchor cable are selected.(3)The stress,strain,plastic zone and displacement of natural slope and slope after four excavations are simulated by FLAC 3D.The stress and displacement of natural slope and slope after excavation are compared,and the influence of excavation on slope stability is studied.After excavation,the stress,plastic zone and displacement of the slope increase obviously,which indicates that the plastic zone of the slope increases gradually until it penetrates,which has a serious impact on the stress,strain and displacement of the slope.Then two simulation schemes of pre-reinforcement measures are formulated.The stress,strain,plastic zone,displacement change and stability of excavated slope before and after pre-reinforcement are compared and analyzed.The influence of pre-reinforcement measures on excavated slope and the influence of different construction techniques and construction sequence on pre-reinforcement measures are studied.(4)The reinforcement effect of pre-stressed anchor pile is analyzed,and the displacement change characteristics of slope before and after pre-reinforcement measures and the stress of anti-slide pile and anchor cable are studied with monitoring data.It is proved that pre-reinforcement measures have good reinforcement effect on excavated slope,can effectively prevent the formation of plastic zone and reduce progressive damage of excavation,and improve the stability of slope.