Stability Analysis And Protection Of Typical Rock Slope Of Karakorum Highway Phase Ⅱ Project

With the advancement of Karakoram Highway phase II project(hereinafter referred to as KKH phase II project),the hidden danger of rock slope of road cutting to highway construction and maintenance has become a key technical problem with challenges.KKH phase II project is located in the north of Pakistan,with complex geological environment and poor regional stability.The excavation construction in the cutting rock slope will have a great impact on the stability of the cutting high and steep rock slope,especially the metamorphic rock slope.Based on KKH phase II project,this paper evaluates the geological environment conditions of the project site in terms of structure,stratum and hydrogeological conditions.Theoretic analysis of the possible failure modes of rock slopes was carried out,and FLAC3 D was used to simulate the rock slope development.After the excavation,the relevant supporting measures were discussed.The main research work and results are as follows:(1)The regional,structural and stratigraphic distribution of the project site were studied,the action scope of the structural fault zone was divided,the specific location of the stratum exposure was defined,and the geological environment conditions of the project site were evaluated.(2)The rock slope along the project was investigated,the distribution and characteristics of typical dangerous rock slope were discussed,and the failure mode of typical rock slope was analyzed based on the investigation results.(3)Taking the typical rock slope-gneiss slope on the left side of k152 as an example,the stability of the typical rock slope was discussed from the three angles of qualitative evaluation,limit equilibrium calculation and numerical simulation.It was concluded that the gneiss slope on the left side of K152 needs support.(4)According to the characteristics of the sudden sliding of the rock slope of the road cutting,the support methods for emergency support and emergency rescue in the later period were proposed,including self-drilling anchors,grouting steel flower tube,and the support simulation of the gneiss slope on the left side of K152 shows that the support method was reasonable and reliable.