Study On Settlement Characteristics And Differential Settlement Control Of High Fill In Loess Gully Region

In recent years,with the construction of infrastructure such as roads,railways,and civil aviation,more and more high-filling projects have emerged.High filling has problems such as large settlement and large differential settlement,which has an adverse impact on the construction of the project.This paper takes the high fill project of Luliang Airport in Shanxi Province as an example to analyze the settlement and horizontal displacement and slope stability of the high fill in the loess gully area.The effects of three different filling methods on the settlement and horizontal displacement of the filling body were studied.The slope ratio,the platform width of the trapezoidal slope and the influence of four different rainfall conditions on the slope stability were analyzed.The main research results as follows:Firstly,the settlement characteristics and horizontal displacement of the filling body under the common layered backfilling method are analyzed.The gap method,the near-slope backfilling method and the geogrid reinforcement method are compared to explore a suitable method to reduce the soil displacement.The settlement of soil is U-shaped,and the maximum settlement position is on the side of the free side of the slope.On the same horizontal plane,the horizontal displacement of soil gradually increases along the x-axis direction and reaches the maximum at the shoulder of the slope.As a whole,the horizontal displacement of the slope is the largest at or near the foot of the slope.The settlement of soil gradually decreases from top to bottom.The gap method and the near-slope backfill method have significant effects in suppressing the horizontal displacement of the soil,but the effect on reducing the settlement of the soil is small,however the gap method is better than another.The minimum settlement of backfill with geogrids is 29% different from that of the ordinary layered backfill method,and the maximum difference ratio is about 46%.Meanwhile,the horizontal displacement difference is about 9.2%.Geogrid reinforcement method can effectively reduce the differential settlement and horizontal displacement of soil.Secondly,the slope ratio of the slope and the platform width of the trapezoidal slope are analyzed to influence the displacement and stability of the slope.When the upper working surface is fixed,the larger the slope ratio is,the higher the safety factor of the slope is,and the more stable the slope is.When the slope ratio is the same,the trapezoidal slope is used for backfilling.It can be found that the wider the platform,the more stable the slope can be.It can effectively prevent the decline of the soil.The larger the slope ratio,the smaller the settlement of the soil at the slope,the smaller the horizontal displacement.And the wider the width of the platform,the smaller the horizontal displacement and settlement of the slope.Finally,four types of rainfall(storm,heavy rain,moderate rain,and light rain)were applied to the slope to study the displacement and stability of the slope.The rainstorm with large rainfall per unit time but short rainfall time has little effect on the soil without considering the rainwater flushing on the slope.The other three types of rainfall have different effects on the slope at different locations;Under the four rainfall conditions,there are obvious through-surfaces on the slope,and the slope needs to be strengthened.