Abstract:After geo-engineering investigation and geophysical exploration in a shanty town reconstruction project in Zaozhuang city of Shandong province, it is showed that there are some mined out areas and mining roadways under the foundation of some buildings and garages. According to the results and recommendations of the previous work, a already found tunnel has been grouted. After the treatment, by using high density resistivity method, it is found that the apparent resistivity increased, the original low resistivity anomaly area significantly reduced or disappeared, the goaf grouting and non grouting in goaf has obvious electric differences. Non-grouting area has an obviously low resistivity. It has provided comparison and references for grouting effect. But when the detection of grouting is carried out by using the resistivity method, the cement slurry consolidation should be ensured, otherwise, the data gained from the interpretation of the results will be affected. The apparent resistivity can not effectively be distinguished whether is is caused by the original water filling goaf or by unconsolidated cement. This method can provide some references for construction of the project.