Cause Analysis and Treatment Measures of Instability of Side Filling Subgrade in a Station Yard
After the completion of the filling of the bottom layer and surface layer of the subgrade of a station yard,there are many through cracks in the back pressure berm at the slope toe and the top surface of the subgrade,which seriously affects the safe operation of the adjacent existing line above the side filling subgrade.Through the supplementary investigation and field investigation,combined with the slope stability calculation,the disaster mechanism of side filling subgrade is clarified,and the emergency reinforcement measures and treatment scheme are put forward according to the field situation.The results show that the excavation of the foundation pit of the new adjacent parallel subgrade with large slope without support causes the unloading of the slope toe of the side filling subgrade,which leads to the traction deformation of the side filling subgrade slope along the weak structural plane;the excavation of the foundation pit of the adjacent line without support causes the slope stability coefficient to decrease from 1.28 to 0.93,which does not meet the stability requirements of the subgrade slope;setting steel sheet piles between the existing line and the side filling subgrade and removing earthwork and reducing load of the side filling subgrade can be used as a temporary emergency reinforcement measures.Steel pipe piles combined with grouting can reinforce the existing line slope,remove earthwork of the side filling subgrade,and excavate and backfill synchronously with the new adjacent line which can be used as permanent engineering treatment measures.It has been proved to be an effective treatment measure by field verification,and has good economic and social benefits.
side filling subgradefoundation pit excavationtraction deformationslope instabilityemergency reinforcementrectification measures
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