Experimental study on overlying karst collapse under the action of underground corrosion

Abstract

[Objective] It is of great significance for the study of karst collapse mechanism to clarify the role of water creep in overlying karst collapse. In order to determine the collapse mode of covered karst collapse under the action of underground corrosion, [Methods] A physical model device was designed and built, and the physical model test was carried out on the basis of field investigation, combined with the engineering geological conditions and drilling data in the study area, taking the collapse of Xinsheng Street and Minzhu North Road in the abandoned Yellow River area of Xuzhou as the research object. [Results] The result show that the collapse shape of Minzhu North Road is nearly circular, with an average collapse range of 35 cm and an average collapse depth of 26 cm. The collapse shape of Xinsheng Street is nearly circular, with an average collapse range of 23 cm and an average collapse depth of 17.75 cm. [Conclusion] The results show that the soil layer of Minzhu North Road has evolved from the initial “cave-type” collapse to the “hourglass-type” collapse, while the soil layer of Xinsheng Street has been an “hourglass” collapse from beginning to end. The size of the collapse pit of the “hourglass” collapse is related to the thickness of the soil layer; the thicker the soil layer, the larger the collapse range. The displacement curve of the surface layer of the soil at Minzhu North Road showed a fluctuating upward trend, while the displacement curve of the surface layer of the soil at Xinsheng Street showed a stepped upward trend. The faster the latent erosion rate, the faster the soil particle loss rate, the larger the soil settlement, and the more likely a ground collapse will occur. The larger the particle gradation of the original soil layer, the larger the particle gradation of the soil that passes through the pipeline after latent erosion, and vice versa. The experimental study of the evolution process and characteristics of karst collapse under latent erosion has practical significance and reference value for the prevention and control of karst collapse.

Keywords

underground corrosion / covered karst / collapse characteristics / physical test / influencing factors / deformation / groundwater