Study on the Seepage Field and Underground Erosion of a Loess Pipeline Foundation

Abstract

Because loess underground erosion is one of the major engineering geological problems in loess areas of China, foundation loess of the Zichang-Yongping section of West-East Gas Pipelines is taken as the research object. The soil-water characteristic curve (SWCC) and hydraulic conductivity function (HCF) of samples have been obtained by laboratory tests, and on this basis, seepage field numerical simulations of loess foundation with and without the pipelines have been processed by the finite-element method. Critical groundwater seepage velocity of underground erosion and the relationship between groundwater seepage velocity and underground erosion velocity have been tested by self-made instruments. Results of tests and numerical simulation indicate that the pipelines not only change the original seepage field of a loess foundation, but also accelerate the underground erosion of a loess foundation. Loess on the top and upstream groundwater side of pipelines will be eroded first, finally causing the failure of foundation and the exposure of pipelines. The combination of soil solidified material and revegetation is suggested as an effective and durable solution to deal with the underground erosion problem of loess pipeline foundations.