Refined exploration and modeling of complex karst in a residential area of Zunyi City

Abstract

[Objective] With the implementation of the strategy of large-scale development of the western region, the problem of reducing the mechanical properties of the foundation caused by karst geology has gradually emerged, which has had a non-negligible impact on the construction of the project and the safety of the people. At the same time, complex karst caves are often difficult to be accurately detected due to their concealment, which further increases the risk of engineering construction. Therefore, a combination of qualitative and quantitative analysis was established to accurately detect and characterize karst caves. [Methods] Taking the karst cave detection in a residential building construction project in Zunyi City as an example, firstly, the high-density electric method is used to detect the field area, and the data of the direction and development range of the karst cave are obtained. Secondly, 3D laser scanning technology was used to obtain detailed data of karst cave morphology and three-dimensional spatial distribution. Finally, the high-density electrical detection result and the 3D laser scanning result were compared and analyzed. [Results] The result show that the cave strikes NNW-SSE from the high-density electrical inversion result, and the 3D laser modeling shows that the buried depth of the cave gradually increases from north to south, and the total volume of the cave is 2 795.48 m³, the height is between 0.5~8.57 m, and the width is between 1.97~23.34 m. The combination analysis of the two method shows that the plane position deviation of the karst cave is between 0~18 m, the deviation rate is 0%~112.5%, and the depth deviation is between 2~8 m, and the deviation rate is 8%~33.3%. [Conclusion] The result show that the high-density electrical method combined with 3D laser scanning can be used to detect karst caves, from qualitative analysis to quantitative description, the information of the buried depth, height change and development scale of karst caves, as well as the deviation rate obtained by comparative analysis, which can identify karst caves that cannot be entered by humans, and realize the fine detection of complex karst caves. It can be seen that the combination of high-density electrical method and 3D laser scanning method is an effective combination of technical method for fine detection of karst caves.

Keywords

complex karst cave / high density electrical method / three-dimensional laser scanning / fine detection / 3D laser modeling / grouhdwater / flow