| Earth-rock dams are widely used at home and abroad due to their advantages such as low cost of local materials,strong adaptability to terrain and geological conditions,good seismic performance,simple construction technology,and rich experience in dam construction.With the continuous increase of earth-rock dam buildings,corresponding complex engineering problems have also emerged.The anti-seepage reinforcement treatment and seepage analysis of earth-rock dam foundations among them have been the research topics,which have attracted much attention in the construction of earthrock dam water conservancy projects.Alpine regions usually refer to high altitude(or high latitude)and perennial low temperature regions,such as the Qinghai-Tibet Plateau,Gansu,and Inner Mongolia in China.In recent years,with the rapid development of China’s central and western regions,the development and utilization of hydropower resources has also shifted to high altitude and alpine regions such as Tibet.Alpine regions such as Tibet have the characteristics of large day and night temperature differences,large annual temperature changes,and cold winters,and there are relatively few existing water conservancy projects.The information available for construction of earth and rock dam projects in this region is limited,so analysis Exploring the antiseepage reinforcement treatment and seepage analysis of earth and rockfill dam foundations in high and cold regions is of great significance to support the development and utilization of hydropower resources in western China.(1)Vibration crushed stone pile is an effective method in the current foundation treatment.This article first discussed the principle of vibratory crushed stone pile reinforcement for different foundations(sandy soil,cohesive soil).Secondly,the article introduced the design method of vibro-rock crushed stone pile from the aspects of design principles of vibro-rock crushed stone pile and calculation of bearing capacity of composite foundation,and briefly described the main construction technology and quality control of the foundation treatment method,which lays the foundation for the application of the method in earth and rock dam foundation treatment in the alpine region.(2)The basic principles of seepage were explained,and the derivation and solution of the basic equations of seepage were discussed in this article.The main steps of seepage analysis using Geo-Studio software Seep / w module were also introduced.Subsequently,the main measures of seepage control were analyzed,and the concrete seepage control wall and curtain grouting were analyzed in detail from three aspects: principle,design,and construction.(3)In this article,the foundation treatment of the Tibet Juba Reservoir dam in the alpine region was taken as a research example,and the principle and method of vibrating and crushing stone piles,seepage control and analysis were proposed,and a treatment method for the foundation’s anti-seepage reinforcement was proposed.In terms of strengthening the vibratory crushed stone pile foundation,the diameter of the vibratory crushed stone pile was designed to be 1.0m,the depth was determined according to the foundation conditions,and it was 1.0m lower than the elevation of the foundation on which the sand layer is located.The pile distance was 1.5m,2.0m,2.5m,3.0m according to the actual situation,and the plum piles were arranged.According to the test pile results,the strength of the composite foundation formed by the treatment of the designed vibro-rock crushed stone pile meet the design requirements.In terms of anti-seepage treatment of the dam foundation,the dam foundation covering layer was designed with a concrete impervious wall,and the bedrock under the covering layer was adopted with a curtain grouting anti-seepage technology.According to the results of the seepage analysis,under the designed anti-seepage treatment,the seepage flow and the drop of the seepage ratio all meet the project’s requirements for seepage stability. |
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