Flexible Supporting Technology Treating Landslide Of Baise Expansive Soil Cutting Slope And Its Effectivesess Analysis

When it's in the construction process of Bailong expressway in Guagxi, large-scale collapse had happened in K154+760, which spans the distribution area of Baise expansive soil. The collapse's is 33 m wide,100 m long and 19 m high, and up to 30,000 m3 of earth. Although the technology of flexible supporting structure has been successfully treated many expansive soil slopes of expressways in Guagxi, most of them are for small collapse. It needs practice and analysis to test whether this technology can be used in such a large collapse. This dissertation is combined the issue, doing research about applying and availability of flexible supporting structure in Bailong expressway.It's by taking basic soil properties and soil strength tests, to get the shear strength and the relationship between the expansive force and moisture content as well as the adsorption strength. And the necessary parameters of the design for the treatment and stability analysis of slope before and after the treatment are provided, then get the reasons of collapse.For the specific geological conditions and damage conditions, the program of flexible supporting structure is designed with pertinence. It attaches importance to clearance of earthwork and basal processing and slope surface drainage, width of slope reinforcement and layered backfill compaction. The design point is ensured to be carried fully by the construction process monitoring. And the technology of flexible supporting structure has treated the large-scale expansive soil collapse rapidly and economically.Assume the slope directly backfill expansive soil without geogrid Bishop, then the stability is analyzed in three states:at constant moisture content (in short-term stability), at dry crack existence (adsorption strength), at infiltration of rain (expansive force), by taking Bishop Formula amended with adsorption strength and swelling pressure, to judge whether use flexible supporting structure or not.It's the numerical simulation of treated slope to verify the effect of treatment of the collapse, according to the similarity of the temperature field and humidity field, the function of FLAC thermal-mechanical is used to imitate expansion force and geogrid is imitated by cable structure element, the results show that the slope is stability after treatment, thus proving the effectiveness of flexible supporting structure to treat expansive soil collapse.This article provides a case of treatment to the large-scale collapse by technology of flexible supporting structure, and takes analysis and proof of its necessity and availability, what can promote the popularization and application of this technology.