Research On Grouting Effect Detection And Assessment Method Of Experiment For Beijing-Shanghai High-speed Railway Shallow Section Karst

GPR technology, as a matured developed means of detection, has a wide range of application. With its low-cost advantages and high efficiency, there are many applications in the quality detection of karst roadbed grouting.The project of detection on karst roadbed grouting is characterized as large region of detection, special circumstances, particular assessment methods, and so on. There is no definite answer whether it's feasible to detect grouting with GPR technology as the comprehensive quality assessment method. If the answer is yes, then what are the evaluation methods and assessment criteria? These two issues are the key points to this paper. So the paper makes a lot of research and analysis on the site experiments of Beijing-Shanghai High Speed Railway—Shandong Zaozhuang karst roadbed project, and the research ideas and results are as follows.First of all, the paper finishes the following tasks: first, the paper sums up the typical characteristics of radar images of karst roadbed geological body and unusual objects based on the exploration data and a large amount of test data. Second, the paper makes some theory analysis on the grout distribution and characteristics of radar response. Through site observation and testing of experimental data, the paper gets out the distribution regularity of grout in the rock and soil mass and its radar images' characteristics. Third, analysis focuses on how to assess grouting effect by the before and after soil and rock grouting, surface and deep embankment' radar images. The paper makes a radar testing experiment on an observed karst cave filling with cements, and has a better understanding of the laws of serous cave filling and characteristics of its radar images. Fourth, the paper makes an analysis on post-grouting radar detection data for a large region, and demonstrates that it's feasible and effective to assess large region's grouting quality by GPR technology. Fifth, the paper makes a classification of typical grouting defects of karst roadbed.Based on the above work and understanding, this paper comes up with the evaluation methods and assessment criteria on the effect of grouting of Kars roadbed. The paper proposes that to assess the quality of grouting, it can be carried out from different directions, different geological media layer, different diseased geologic body, range of examination. And the paper classifies the grouting effect as good and bad qualitatively. Also the paper provides detection cases of both two types. According to this classification and comprehensively based on the above research results, the paper tries to establish Assessment Criteria Table of Grouting effect. In the last, the paper introduces the optimized proposal for detection which is summarized from the site experiment and experience to reduce the radar interference.