岩溶路基注浆效果透水率检测标准试验研究

Experimental Research on Permeability Critical Standard for Grouting Quality of Karst Subgrade

研究目的:透水率检测标准制约着岩溶路基注浆效果的有效评价。通过模型试验和理论分析,研究影响透水率检测标准应用的两个关键性基础问题:一是是否存在一个不产生潜蚀塌陷的界限裂隙;二是如果存在这个界限裂隙,那么界限裂隙的透水率特征值是多少。研究结论:临界裂隙开度是覆盖型潜蚀塌陷的关键控制因素,受覆盖层土质、密实度、临界水力梯度等因素的影响,覆盖型岩溶路基塌陷的临界裂隙开度约为2～4 mm;对溶蚀裂隙发育的可溶岩地基,当裂隙宽度小于等于3 mm(或地基透水率小于等于47 Lu)时,在自然水降条件下,不具备岩溶潜蚀塌陷条件,因此,建议以47 Lu作为潜蚀塌陷临界透水率值,以此为岩溶地面塌陷防治注浆效果检测定量标准。

Research purposes： The permeability critical standard is important for the assessment of grouting quality of karst subgrade. The two key problems were studied thought doing the model test and making theoretical analyses. One was whether there was a critical fissure that could not bring about the underground erosion collapse or not. The other one was if there was such a critical fissure, what was the characteristic value of the permeability of the critical fissure. Research conclusions： The study results showed that the width of the critical fissure was the key factor for the collapse of covered karst due to the subgrade erosion, the soil property, the compactness and critical hydraulic gradient of the cover, and the collapse width of the critical fissure of the covered karst subgrade was about 2 ~ 4 ram. For the dissoluble rocks subgrade with development of erosion fissure, while the fissure width was less than or eoual to 3 mm. or the permeability of karst subgrade was less than or equal to 47Lu, the covered karst subgrade would not collapse under the natural condition. Therefore, it is recommended that the 47Lu should be regarded as the permeability critical standard for grouting quality of karst subgrade.