STUDY ON STABILITY OF SPOIL GROUND IN LOESS GULLY REGION

With the continuous advancement of infrastructure construction,unreasonable stacking of excavated soil(spoil) has become one of the important problems in engineering construction. As the spoil ground increases in volume and height,the risk of instability within the deposit increases,which may result in water and soil erosion,ecological environment damage and other disasters. This paper takes the spoil ground in the loess gully region of a high-speed railway tunnel in Gansu Province as a research object and uses laboratory test,field test and numerical simulation research plan to explore and examine the mechanical properties,compaction degree and slope cutting type setting of deposit under different parameters. The results show that cohesion and internal friction angle of spoil soil have a positive correlation with dry density and a negative correlation with water content,but the internal friction angle is not affected by moisture content. The compaction during the layering process of spoil soil can significantly increase the surface compaction degree. The compaction degree of the middle and bottom layers increases significantly with increasing in the number of compaction. The average compaction degree increases rapidly in the early compaction process,but its change range decreases significantly with the increase of the number. The average moisture content shows a trend of decreasing at first,and then increasing in the compaction process. During the parameter setting of the slope steps,the magnitudes of stress and displacement deformation increase with increasing in height step and slope rate,and decrease with increasing in platform width. The stability coefficient of slope decreases with increasing in height step and slope rate,and increases with increasing in width platform. Through comprehensive analysis of curve,the slope stability shows that the sensitivity of step parameter setting in stress,displacement and stability coefficient from high to low is step slope,platform width,and step height in turn.