Study On The Application Of Cone Penetration Test In Quality Inspection Of Sluicing-Siltation Earth Dam

Building dams with sluicing methods were widely applied and spread in recent years. But there were no systematic and scientific methods to test the sluicing-siltation earth dam. The objective of this study was to test the quality of Qianguaigou silt dam in Zhidan county of Yan’an city in Shaanxi province with cone penetration test through analyzing the cone penetration test data of side ridge compacted layers, dam top compacted layers and sluicing-siltation filling layers. With the advantage of SURFER software, a contour map of specific penetration resistance would be drawn quickly. It was easy to process and analyze the large amount of cone penetration test data and present the strength in different positions of the dam exactly.With those, the quality of sluicing-siltation earth dam could be analyzed. The relationship between soil water content of sluicing-siltation earth dam built by silt loam and specific penetration resistance for cone penetration was founded determine the position of flow condition. It could be easy for the method of using cone penetration test to determine the position of flow condition in sluicing-siltation earth dam to apply and expand. It was wished to form completed, systematicand scientific sluicing-siltation earth dam quality inspection way by combining the new method with traditional methods.Some conclusions were conducted as follows:(1)The grading analysis test and liquid and plastic limits test for earth material showed that: According to the rules of《specification of soil test》(SL237-1999), the earth material was belonged to low liquid-limit clay. According to the rules of《technical specification for sluicing-siltation earth dam》(SL302-2004), the earth material was belonged to silt loam.(2)By analyzing the changing laws for specific penetration resistance of side ridge compacted layers, trimming slope and rolling method during the construction were found affecting the quality of side ridge compacted layers. The outside of side ridge compacted layers were less strength. There were crack and sinking in bad weather. Through analyzing the changing laws for specific penetration resistance of dam top compacted layers, the thickness of filling earth and compacted quality for each time could be confirmed. Analyzing the changing laws for specific penetration resistance of sluicing-siltation filling layers was to evaluate the uniformity of sluicing-siltation filling. Variation coefficient(CV) was used as index of quantitative description to evaluate the quality of sluicing-siltation filling.(3)The relationship between soil water content and specific penetration resistance was expressed as power function and it was significant different, the fitted equation was: y=0.018x-2.72(y, specific penetration resistance; x, soil water content).When using the cone penetration text to determine the position of flow condition in sluicing-siltation earth dam, the data in《code for in-situ measurement of railway engineering geology》could be used directly to study the whole sluicing-siltation filling. The relationship between soil water content and specific penetration resistance should be founded based on the data in 《code for in-situ measurement of railway engineering geology》. With these, critical specific penetration resistance corresponding to different plastic state of earth material could be figured out.(4)A contour map of penetration resistance could be drawn quickly with the advantages of SURFER software. Workload was less. The contour map of specific penetration resistance could help us to process and analyze a large amount of cone penetration test data and present the strength in different positions of the dam more exactly. It would be convenient for further study. Adjusting the grade of contour lines in the contour map of specific penetration resistance and filling suitable color could pertinently analyze the dam compacted layers and sluicing-siltation filling layers. To the dam compacted layers, the colorful contour map of specific penetration resistance could present clearly the strength of compacted layers in different positions of dam. In addition, to analyze the quality of compacted layers in different positions of dam. During construction, to speculate the area where bulging, deformation and piping erosion often appeared. After construction, to support scientific basis for strengthening the dam. The partition map of dam plastic state related to sluicing-siltation filling layers could present clearly the specific scope of five plastic state zones. In that, flow condition should be paid high attention. The partition map of dam plastic state for different time could be used to analyze the formation and development for the dissipation of flow condition. And then to judge the safety and stabilization of the dam.