| With the gradual implementation of the western development strategy, the economic growth rate of the Midwest and the Northeast region has exceeded the eastern region for over 5 years. This marks that the long-standing trend of regional development disparities has been initially contained and the new regional development strategy layout is taking shape. In this environment, the airport construction in the southwest of China is coming into a promptly developing period. Due to the topographic conditions, airport construction in regions of undulating terrain such as mountains, hills have to make a lot of cut and fill, And as the large area, high fill embankment height, so selection of reasonable filling scheme, especially the suitability of the filler, has important significance to embankment stability and economic benefit of the project.The thesis focuses on the high fill area of a reservoir of some red layer airport in Chongqing, the mixed padding of sandstone and mudstone is used to fill the reservoir. First of all, the engineering geological condition of the study area is found out by engineering geological mapping, field drilling and laboratory tests. Based on this, the samples of sandstone and mudstone located at excavation sections along the reservoir are taken, then the laboratory tests are conducted, The most reasonable mixing ratio and the optimum moisture content are obtained by the compaction tests with different mixing ratio of sandstone and mudstone and different moisture content. the shearing strength and the osmotic coefficient of the padding are measured under the natural and saturated conditions. Through analyzing the test data we mainly obtain these following conclusions:(1) According to the compaction test, the optimal mixed proportion of sand and mudstone mixture in the study area is 4:6, the optimal moisture content is 11%, the maximum dry density in the complete compaction was 2.13g/cm3.(2) mudstone were determined in the optimal water content and the mixed proportion, In natural conditions, с is 130 KPa and φ is 32°; In the saturated conditions, с is 119 KPa and φ is 17.5°; The permeability coefficient of the sample by the change of the hydraulic head was 0.44 × 10-6~0.48 × 10-6cm/s.(3) Analysis of fill slope using limit equilibrium method in natural condition of fill slope in basically stable condition; In the course of the high rainfall and reservoir water level rise, the stability coefficient of the slope meets the requirements of design codes. but with the falling of the reservoir water level and fill slope began to instability, and reservoir water level decline rate is faster, calculated the slope stability coefficient is small, fill slope more easily instability.(4) The result about the stability of the high fill slope by the finite element method is the high fill slope is basically stable under the natural condition in the study area, but under the condition of heavy rainfall and the rise and fall of water level of the reservoir, In extension area from the original slope to the top of the filling body Clear plastic zone through surface,It is The potential sliding failure surface,almost the same on form with The shear strain increment.The potential failure surface is filling body, Filling slope easily through the plastic zone along the slip surface to produce a whole.(5) Through from economy, settlement deformation and slope stability of mixed sand shale filler were suitable for evaluation; the packing is not suitable as filler of the airport in the study area under the influence of heavy rainfall and reservoir water level fluctuation and.(6) The study area is a stable condition with improvement scheme of the filling programme using weathered mudstone filling of reservoir filling area in a lifting range of seepage line class after replacement of the sand and mud mixed packing, after filling in natural conditions and storm conditions. |
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