Experimental Study On Compacted Loess And Settlement Prediction Of Landfill Foundation

The filling project is an indispensable part of engineering construction,and in loess area,the high fill-in project also occupies an important position in the filling project.The quality of fill-in project and post-construction settlement are common problems in engineering construction.In this paper,through the soil mechanics test of loess filling under different compaction conditions,the main characteristics of compacted loess and the relationship between compressive strain and time were discussed,and the settlement of fill foundation was estimated.The main work and conclusions are:(1)The compaction tests of loess under different compaction conditions were carried out,discussing the change of dry density under different compaction energy and moisture content.(2)The direct shear test was carried out on compacted loess,analysing the influence of the compaction energy and moisture content on the shear strength index,and showed that: At the same compaction energy,the cohesion force c maintained at a relatively small value range under a higher moisture content(w?21%),showing a decreasing trend with the increase of compaction energy.And for the loess sample in this test,the cohesion increased with the increase of moisture content when the moisture content was less than 12%.(3)The high pressure consolidation test of the compacted loess was carried out,discussing the influence of compaction energy,moisture content and humidification on compressibility,and showed that: Under the same compaction energy condition,the higher the water content on the dry side(w < wop),the lower the compressibility of thecompacted loess,and the higher the water content on the wet side(w > wop),the higher the compressibility.The compression amount and the change rate of samples under various pressure after humidification were obviously greater than those without humidification,and the increment of sedimentation amount was larger if the compaction energy was smaller and the initial moisture content was lower.(4)Using the results of high-pressure consolidation experiments,the relationship between compressive strain of compacted loess and moisture content,compaction energy,and time was analyzed,indicating that at a lower moisture content(9% and15%),compressive strain and time ?-lgt could be fitted by a straight line relationship,but at a higher moisture contents(18% and 21%),strain and time were more suitable to use quadratic polynomial fitting.(5)Using the ?-lgt linear relationship obtained by compaction loess high pressure consolidation test,the forecast method of the relation between settlement and time of high fill loess foundation was put forward.Settlement amount and settlement rate calculation formula based on the relation of line fitting was obtained.The stable settlement and time prediction of the filling foundation under different compaction conditions were estimated,and the results showed that the compaction energy and water content had significant influence on the settlement amount and the time required for the settlement stability of high fill foundation.