Research On The Detection Technology Of Cave On The Bottom Of The Cast-in-place Pile

Road building leads development to the grand west, construction of roads and bridges plays a significant role in the grand west China development, complication during which lies vast differences in landscape, with hazardous of continuing caves beneath. With answers about how to detect, measure and fill up empty caves since become a issue that concerns regulators before build up in this enormous construction. To lower the danger, the project of bored pile requires adequate detection in advance although no evaluation are consider as a solution at the moment.Technical team has been exploring and researching with technology like radar, high density electrical and TEM instrument on site, contribution to which effectiveness still need to be improved. To sum up,research in depth still need to be called in place.Firstly, on the basis of knowledge and understanding of a variety of geophysical methods, combined with environment and characteristics of cast-in-place pile in prophase, metaphase and anaphase, analyzed the applicability of the various geophysical methods in these three stages. This paper focuses on the cave detection methods which is on the bottom of the bored piles, through the comparative and analysis,selected seismic CT method as the detection means to detect the cave.Secondly, based on the understanding of the principle of the seismic CT method, Expounded the principle of the well-ground (crosswell) seismic CT method’s setting of observing systems, data processing and Interpretation of seismic data; and then introduced the forward and the inversion theory of seismic and their algorithm.By contrast the advantages and disadvantages of each method,selected the ray tracing method based on linear interpolation to forward simulation,useing the BPT algorithm results as the initial value,then useing SIRT algorithm to inverse computation.Finally, using the Tesseral2-D seismic simulation software, simulated the cast-in-place pile bottom cave detection, Through the simulation results obtained,and inversion imaging proved practicality, feasibility and reliability of well-ground joint crosswell seismic CT method in theory, which used in detecting the cave on the bottom of cast-in-place pile.