| With the rapid development of China’s urbanization, a lot of deep foundationpits appear with a surge of high-rise and super high-rise buildings. In the process ofexcavation, it tends to appear varying degrees of foundation pits surroundings andcontinuous wall leakage problem, which directly affects the safety of constructionworkers and the progress of project, and has significant impact on the futureconstruction molding.This paper analyzes the problems involved in the leakage of concrete diaphragmwall and its detecting in the field of project construction, and discusses the feasibilityof the geophysical methods on detecting the leakage. Adopt the technologies whichare shallow seismic exploration methods including common reflected wave methodsand seismic exploration between wells or CT methods between wells combined withelectromagnetic exploration methods to detect surrounding leakage. On seismic aspect,this paper mainly finish the study of forward simulation for the theoretical models.Firstly deduce and build the basic formulas of wave equation finite difference, thenset up boundary conditions of surrounding leakage. Building several representativeconcrete diaphragm wall theoretical models based on actual possibilities, design thecorresponding observing systems and do the research on the numerical simulations ofseismic wave field. Based on the results of simulations, analyze the transmissionfeature and spread characteristics of seismic waves. The results analysis shows thatseismic exploration methods can detect foundation pit surrounding leakage and canindependently or combined with other geophysical exploration methods detectfoundation pit surrounding leakage.To detect leakage more reliably, we discuss the potential monitoring method.The basis of applying potential monitoring method into leakage detection of deepfoundation pit continuous wall is that water content of the soil affects soil electricalparameters, such as soil resistivity. We detect the surrounding leakage in actualproject applying parallel electrical method, laying receiving and acquiring device, and electrifying and acquiring data through main control station. Finally, we analyze theelectric field obtained by respective electrodes, and determine the leakage ofcontinuous wall and approximate location of leakage. Comparison of the results withknown actual situation indicates that potential monitoring method is feasible to detectsurrounding leakage, and can be combined with seismic wave method. |
