Study On The Effect Of Phyllite Filler Gradation For Subgrade Stability

The eastern Ankang section of the highway from Shiyan to Tianshui pass through theregion where distribute a large number of strong weathered phyllite, and the filling origin ofbuilding the embankment is limit.Phyllite as embankment filling is different from soil fillingand hard rock filling. Its grain size will change with the process of rolling compaction, thelength of bareness time and the condition of moisture content. So the gradation has bigdifference between field and indoor test, which lead to the result of indoor test can’t be whollyused in field. The article takes the strong weathering phyllite as the research object, analyzingthe change of gradation to determine reasonable graded scope through indoor test and fieldtest. At the same time, it based on the characteristic of phyllite has low strength, analyzinghow gradation influence mechanical properties of phyllite after improved. On thebasis,relying on the test road,it put forward phyllite subgrade filling scheme and theconstruction technology, making a series of research results:1） Analysis the nature feature of roadbed filling along the “Shiyan toTianshui”highway.and through the indoor diffraction test and uniaxial compressive strengthtest, analyze physical and mechanical properties of phyllite. The result shows that strength isbelow30MPa, which belong to soft rock and is ease to break.2）In order to analyze phyllite filler after packing construction “sledging” characteristics,with different amounts of rock of phyllite filler, simulation field construction process,proceed the compaction test and screening test indoors, analyze its level moisture content andbest matched maximum dry density, the effects of on this basis, recommend phyllite fillerreasonable original distribution in the range.3）Based on cement modified phyllite mechanism, to improve the different stone contentof phyllite filler， through the compaction test, CBR test and lateral restraint without thecompressive strength test, analyze the gradation of improved particle size change phylliterock subgrade with influence on the performance of the road.4） Rely on“Shiyan to Tianshui”highway shanxi ankang eastern25mark ZK22+790-ZK22+860section;From the point of improving road mechanic performance andmaking sure road water stability, Puts forward the improved phyllite cement packing rock subgrade scheme and rock subgrade drainage design project; Puts forward the improvedphyllite cement rock embankment and cement packing of improved not screening gravel roadbed part of the construction technology, construction process and the matters needingattention; And testing after the subgrade filling, the results show that the effect of stabilitycement improved rock subgrade is good.