压水试验在岩溶路基注浆效果评价中的应用研究

文章介绍了已有的岩溶路基注浆效果检测方法，在此基础上分析压水试验定量评价岩溶路基注浆效果的可行性，并以黔张常铁路岩溶路基注浆代表性压水试验段为例，采用4种合格标准对路基注浆效果进行分析，以弥补目前使用的合格标准存在的不足。在多次优化试验的基础上，制定了新的压水试验定量评价注浆效果判定标准，总结出压水试验工艺参数，采用单点法压水试验，注浆前后压水试验数量分别不小于5%和4%，试验压力在0.05~0.25 MPa，试验长度为3~6 m，压水时间为5~10 min?次-1。经多次、多段其他检测试验验证其工艺参数和评价标准的结果表明，该方法是一种适合的、可靠的定量评价岩溶路基注浆效果的方法。

Application of pressure water tests to evaluation of grouting effects on the karst roadbed

Karst is common in the area where the Guizhou-Zhangzhou-Changzhou railway passes through, of which landforms are characterized by depressions, sinkholes, caves and cracks. The roadbeds in this area are mostly susceptible to collapse as shown by regional geological evaluation. The consistency of evaluation of grouting effects is a difficult issue. At present, there are many methods to evaluate the effect of karst treatment, which, however, are mainly qualitative. This work aims to explore a quantitative method by pressure water tests to evaluate the grouting effect in karst areas. Firstly, various evaluation methods are presented. Then feasibility of quantitative evaluation of grouting by pressure water tests is analyzed. A representative section of grouting tests at the karst roadbed of the Qianjiang-Changde railway is selected as an example and the different cases with four kinds of qualified criteria are examined, indicating that the current qualification criteria have some advantages and disadvantages. Combined with theoretical analysis and practical application, a new criterion for quantitative evaluation of the grouting effect is established on the basis of many tests and optimization schemes. And the technological parameters of the pressure water test are summarized. The pressure water test method used in this work is a single-point method, in which the number of the pressure water tests before and after grouting is no less than 5% and 4%, respectively; the test pressure is 0.05-0.25 MPa, the test length is 3-6 m, and the pressure water time is 5-10 minutes per time. The results show that the new evaluation criterion verified by 44 sections of water pressure tests is more reasonable and accurate than the other single criteria. Meanwhile, the fuzzy evaluation of drilling, and geophysical prospecting is used to verify the criterion again, which suggests that the criterion is basically consistent with other evaluation results, showing good applicability and rationality. In all, this criterion is a suitable and reliable method for quantitative evaluation the grouting effect on the karst roadbed.