The continuous development and improvement of underground pipeline system has brought great convenience to daily life,but at the same time,leakage and seepage of underground pipeline have also brought great hidden dangers to normal life and public safety.Of underground concealed water problem increasingly prominent,many scholars of underground concealed water detection,monitoring and done a lot of research,creating many hidden underground water monitoring methods,such as electrical method,transient electromagnetic method and geological ground penetrating radar method,sonar seepage technology,etc.,but most of the above methods for large scale underground concealed water problems,in view of the small scale urban underground pipeline leak problem,at present mainly adopts the traditional way to listen to leak detection,loading forms area mainly has the sound and the pool water level measurement,etc.,but the traditional method efficiency is slower,and vulnerable to outside interference conditions,Therefore,the potential method is introduced to explore the monitoring problem of small scale concealed water gushing in urban underground space.Under natural conditions,the water in the soil seepage process,because of the positive and negative charges in geotechnical engineering,selective adsorption flow upstream and downstream will generate an electrical potential difference,so this article use the law,through the laboratory experiment combined with theoretical analysis,the method of using building underground concealed chung hydropower signal acquisition experiment simulation system,the research analyzes the potential of underground water pipeline leakage flow of timely response characteristics and spatial distribution,and analyses the influence of water soil and potential response mechanism,explores the gushing water process changes and positioning the influence of water on the soil,judge the trend of seepage direction and scope of seepage flow diffusion.The influence of different conditions on the response characteristics of potential signals was studied by establishing leakage seepage experimental models of underground pipelines under various conditions.Potential inversion tomography is used to accurately identify and detect the location,influence range and development trend of water gushing.The field test system was established to verify the leakage potential response of underground water supply pipeline.Specific research results are as follows:(1)There is a good correlation between the surface potential signal and the variation of water seepage range and the flow velocity state of seepage.By analyzing the time series change of the surface potential signal,the change of the whole seepage process range can be accurately judged,and the expansion trend of the seepage range can be predicted by the change rate of the surface potential signal.(2)The range and state of seepage have obvious influence on the distribution and migration of surface potential nephogram.By observing the potential intensity contour chart on potential size,potential changes in different area,according to the time sequence of each location potential changes reflect the whole process of the spread of the seepage scope,and according to the density of each location potential contour reflects the different positions of seepage velocity and trend,the monitoring and early warning system for the seepage.(3)The potential signal-time curves generated by water leakage and seepage in soil under different conditions all follow the basic law of "rising first and then falling".The characteristics of curves under different conditions are mainly reflected in the stability,rate of change,fluctuation and amplitude of change of curves.Pipeline material has a significant impact on the seepage potential.Due to the electrical conductivity of metal pipelines,potential signal curves of each channel show similar change characteristics,which makes it inaccurate to judge the change of seepage range through the analysis of curve change characteristics.(4)Under different conditions,the change of seepage range has a significant effect on the migration and distribution of surface potential intensity isoline cloud map.The shape characteristics of potential intensity contour cloud map have obvious correspondence with the actual seepage range no matter the different flow rates,the different buried depth of water pipes,the different pipeline materials and the different pipeline laying methods.According to the characteristics of potential intensity and isoline density in each region of the cloud map under different conditions,the migration and variation of seepage range and the development trend can be judged and predicted.(5)Through the method of potential inversion imaging on the seepage range,the water gushing position,influence range and development trend were carefully identified and detected.The inversion imaging results showed that the potential abnormal areas were basically consistent with the variation of the seepage range.(6)The field test system was established to test the leakage potential response of the underground water supply pipeline,and the leakage location of the pipeline was judged by the potential intensity contour cloud map.There are 43 pictures,1 table and 71 references in this paper. |