| Grouting reinforcement is one of the main methods of the roadbed karst remediation.due to the complexity and hidden nature of the grouting, grouting quality testing evaluation is very important. Sounding method and the transient surface wave method are commonly used geophysical methods in karst grouting quality evaluation, but it is lack of system research and the theoretical guidance for electrical sounding measurement to detect the grouting quality of karst subgrade. This thesis is based on the Guilin test section of Xiang-Gui railway expansion renovation project, combined with the indoor electrical sounding test of experience. which will provide the theory basis for the engineering practice.Firstly, the establishment of electrical sounding model test research on the roadbed karst grouting quality, the model has the caverns and fissures, covering layer of clay and gravel soil. Apparent resistivity detection of groundwater and water table to the bedrock surface, before and after grouting, analysis the variation of the resistivity of the model before and after grouting, and evaluation of filling the cave fissure grouting. The test results show that a sequence grouting cave filling rate of approximately65%. When the overburden is gravel soil, the resistance change rate of cave fissure area is about33%before and after grouting, and the grouting effect is obvious. When the overburden is clay and with no groundwater, the resistance change rate of cave fissure area is about12%before and after grouting,and the grouting effect is less obvious, water level to the bedrock surface, the apparent resistivity is almost unchanged before and after grouting. The field test using geological drilling, the electrical sounding method and the transient surface wave three means to evaluation the grouting quality of Xiang-Gui railway expansion and reconstruction project in Guilin test section. Drilling to expose the cave area, the contour map of the electrical sounding method shows a low resistivity anomaly, and transient surface wave dispersion curves show the wave velocity of shear wave plummeted. After grouting, electrical sounding contour map shows low resistance abnormal area is greatly reduced, the wave velocity of shear wave is also a substantial increase in, Drilling to expose the filling is also good, indicating that the grouting good. |
